Docstoc

Download Course Handbook - Grimsby Basic Transvaginal Ultrasound

Document Sample
Download Course Handbook - Grimsby Basic Transvaginal Ultrasound Powered By Docstoc
					DIANA, PRINCESS OF WALES HOSPITAL, GRIMSBY




BASIC TRANSVAGINAL ULTRASOUND WORKSHOP



                  COURSE HANDBOOK



    This guide is for personal use only and its contents remain the property of the author.
                  It may not be reproduced in any form without permission.

                                  Mr I I Bolaji 2003
                  Basic Grimsby Transvaginal Ultrasound Workshop




           Grimsby Basic Transvaginal Ultrasound Workshop
                                  INTRODUCTION

I am pleased to welcome you to the 11th Grimsby Basic Transvaginal Ultrasound
Workshop at Diana, Princess of Wales Hospital, Grimsby. The first workshop was
enthusiastically received in July 1997 and the faculty has thoroughly enjoyed the
participation and enthusiasm of delegates. The Royal College of Obstetricians and
Gynaecologists has granted seventeen CME points with equivalent accreditation from
the Royal College of Radiologists.
Transvaginal sonography is one of the few very important and useful developments in
Obstetrics and Gynaecology in the past decade. The first invention was attributed to an
Austrian called Kratochwill in 1969. However, from the early eighties, its use began to
spread very rapidly.
The reason for the improved diagnostic power and added therapeutic possibilities of the
Transvaginal probe arise from the proximity of the probe to the pelvic target organs, and
the relatively thin vagina, which enable the use of higher sound frequencies. Vagino-
sonography is less angle-dependent than abdominal and because there is minimal fat in
the vaginal, the vaginal scan does not discriminate between the very thin and the
morbidly obese patients.
The Clinical Directorates of both Radiology and Obstetrics recommend that ultrasound
training should be a component for the MRCOG. This training at all stages must include
the technique of transvaginal ultrasound for the examinations of the first trimester
pregnancies.
The topics covered in this Course include theoretical and practical basis of transvaginal
ultrasound sonography and broad clinical application. The primary objective is to teach
every delegate a simple, safe, step-by-step technique of transvaginal scanning, as applied
to obstetrics and gynaecology, and safe interpretation of the various findings.
New        topics     have      been      introduced      this     time      to    include
Teleradiology/ Telemedicine/TeleObstetrics and Screening for malignancy using DNA
Analysis.
I hope, at the end of the Course, all participants will have gained sufficient knowledge
and experience in this new, exciting imaging technique and confidence in the
interpretation of findings. I sincerely hope that you will find your stay in Grimsby for
this workshop a worthwhile venture.
May I take this opportunity to thank all those who have assisted me in the organisation
of this course. This includes the secretarial and administrative support of Ms Lynn
Young, PGMC Co-ordinator, Brenda Hartill, Lesley Tilbury (my secretary) and most
importantly the dedicated women who kindly agreed to participate in the Hands-on-
Session of the workshop.

                                                             MR IBRAHIM I BOLAJI
                                                               [MBBS FRCPI MD FRCOG]
                                                                   COURSE DIRECTOR
                                                                                 2003




                                                                                        2

                  Grimsby Basic Transvaginal Ultrasound Workshop
TRANSVAGINAL SCANNING TECHNIQUE

      STEP- BY- STEP APPROACH




                                                  3
 Grimsby Basic Transvaginal Ultrasound Workshop
                                 EQUIPMENT

1   FAMILIARITY WITH YOUR EQUIPMENT

    Scan machines do vary considerably in their technical details and it is important
    to familiarise yourself with the control panel (remember cock-pit drill). It is of
    paramount importance to be able to perform focusing and contrast controls at
    different depths, controlling of image depth of field, cursor movement and
    measurement of different dimensions and determination of the position of the
    orientation mark on the screen.

2   PREPARATION OF THE PATIENT

    i)     Patient Information

           Patient information is important regardless of the gynaecologic or
           obstetric procedure plan. Informing the patient about transvaginal
           sonography is especially important. A brochure should be available in all
           units in several languages to explain what this involves when
           appointments are sent to patients.

           At the beginning, patients should be reassured and offered a simple but
           thorough explanation about the procedure again and should be shown the
           approximate distance the probe will be introduced into the vagina.

    ii)    Approach And Respect For Privacy

           Bimanual examination is embarrassing and transvaginal scanning (TVS)
           is very embarrassing to the patients. Every effort should be made to
           respect patients' privacy whilst undressing or at the end of the scanning
           procedure.
           The patient should be covered appropriately throughout the procedure
           and permission should be obtained if there are observers in the room.

3   THE EXAMINATION TABLE

    There are 3 possible positions that can be adopted in transvaginal scanning:

    1      Special gynaecological Table

           Special gynaecological examination tables, equipped with
           thigh/leg rest which allow the patient to assume the lithotomy
           position for convenient transvaginal scanning. They are similar
           to couches used for Colposcopy.




              Grimsby Basic Transvaginal Ultrasound Workshop                   4
2   Buttocks - on - Pillow

    Flat, cushioned examination tables with a pillow under the buttocks to elevate to
                   pelvis

3   Buttocks -on -Edge, Feet –on- Stool

    Flat, cushioned examination tables but with the patients' buttocks brought to the
    edge of the table while the feet are resting on a high stool.

4   PROBE INTRODUCTION

    Non-sterile condoms that do not have a reservoir tip are ideal as probe covers
    and keep the transducer free from cross contamination among patients. Three to
    5 mls of transducer gel is placed inside the sheath. Gel is also placed on the
    outside tip of the condom-covered probe to facilitate ease of vaginal insertion.
    The probe having been gelled and covered with the appropriate sheath, condom
    or glove and then introduced very gently through the introitus with care taken not
    to cause undue pain.

5   CONCLUSION OF THE EXAMINATION

    At the end of the procedure the probe should be withdrawn very gently and the
    patient be allowed to dress in privacy. The probe should be wiped with
    appropriate medium, usually a virucidal and bactericidal towlette or spray
    disinfectant must be used to clean probe head and shaft between examinations
    for hygiene and safely stored in its socket. These probes are very expensive and
    should be treated with "TLC".




              Grimsby Basic Transvaginal Ultrasound Workshop                    5
                              SCANNING TECHNIQUE

BASIC PRINCIPLES

1      Regardless of the route selected to perform the scan, a methodical and systematic
       scanning routine should be followed at all times.

2      At the end of the procedure clean the probe with a damp soft cloth or rinse in
       water and wipe it clean with Chlorhexidene wipes or spray. Very often the
       manufacturer will provide you with special instructions to ensure continued
       cleanliness of the probe.

ALWAYS RETURN THE PROBE TO ITS CASE AS BREAKAGES ARE COSTLY.

ORIENTATION

Orientation of the image depends on the characteristics of the ultrasound probe in use.
The plane of insonation may be originating from an end transducer, side transducer or a
combination of both. These differences will determine the appearance of the images on
the screen.

It is important that you always remember the following anatomic landmarks in the pelvis
which will help you during the scanning procedure.

1      The bladder is probably the most important as it is easily identified and is present
       in all patients, unless it has been removed or bypassed by previous surgery. A
       full bladder may affect the ability to demonstrate the ovaries and may distort the
       image, however, a small amount of urine in the bladder is useful as it helps its
       identification.

2      The uterus is the second most important landmark and, unless removed by
       previous hysterectomy, should enable you to establish your orientation in the
       sagittal or coronal planes.

3      The internal iliac vessels. These are located on the side walls of the pelvis and
       their identification outlines the boundaries of the lateral pelvic wall. The ovaries
       are normally anterior and medial to the structures.




                 Grimsby Basic Transvaginal Ultrasound Workshop                       6
 Figure 1. Relationship of the pelvic vasculature and ureter to the adnexa, uterus, and vagina.The iliac
                            vessels are positioned adjacent to the ovary .




Figure 2.         An AP -view of the uterus showing a late follicular endometrium. The endometrial
                 thickness = 15mm. The basalis-myometrium interface is seen (short solid arrow) and
                 some shadowing caused by a small intramural fibroid also is shown (open arrow)


SCANNING PLANES

The two scanning planes that one should concentrate on are the sagittal (also known as
vertical, longitudinal or antero-posterior) and coronal (also known as horizontal, cross-
sectional or trans-pelvic) planes. It is important that, while scanning in the coronal
plane, you should keep the right and left orientations correct at all times.




                                                                                                      7
                    Grimsby Basic Transvaginal Ultrasound Workshop
STEP-BY-STEP APPROACH TO VAGINAL SCANNING

I-   The Uterus

     1     Introduce the ultrasound probe with the insonation plane in the sagittal
           position and the tip of the probe pointing downward and posteriorly.
           This is to follow the natural curve of the vaginal cavity.




                      Figure 3. Introduction of transvaginal probe


     2     Observe the monitor screen during the introduction so as to determine the
           presence or absence of any pathology in the vaginal wall or rectovaginal
           septum and to see the cervix as you approach the anterior fornix. The
           urethra and the bladder base should be to one side of the screen.

     3     Align the ultrasound probe with the longitudinal axis of the uterus so that
           the whole uterus, from the fundal region to the cervix, is visible. The
           entire uterine contour should be examined from the right side to the left
           and from the anterior surface to the posterior.




             Figure 4. Alignment of the probe with the longitudinal axis of the uterus




             Grimsby Basic Transvaginal Ultrasound Workshop                              8
4      Observe the appearance of the cervical canal and endocervical region, the
       regularity of the uterus and the thickness of the endometrium in the
       sagittal plane. If the uterine contour is irregular determine whether there
       are fibroids or not.

5      By altering the direction of the tip of the probe anteriorly more of the
       bladder will be seen, whilst tilting it posteriorly more of the Pouch of
       Douglas will be seen




         Figure 5. Anterior tilting of the probe to see more of the bladder.




    Figure 6. Posterior tilting of the probe to see more of the Pouch of Douglas.



6      After examination of the uterus in the longitudinal plane, rotate the probe
       90 degrees around its axis and make sure that the orientation is correct to
       give you the correct anatomical positions on the screen. Again examine
       the cervical and uterine contours, the outline of the uterine cavity, the
       appearance of the uterine wall and endometrial thickness.




          Grimsby Basic Transvaginal Ultrasound Workshop                            9
            Figure 7.         Coronal or cross section view of the uterus and adnexa.

II -    The Adnexa

        1    From the sagittal view of the uterus, rotate the probe 90 degrees into the
             coronal plane. It is often easier to identify the ovaries in the coronal or
             oblique sagittal than the sagittal plane.




Figure 8.    Illustration of the area being examined in the central "semi-coronal" plane.




                                                                                            10
                Grimsby Basic Transvaginal Ultrasound Workshop
Figure 9 . A cross section view of the area examined above (fig 8) as it appears on the monitor.




   2        When viewing either the right or left ovary it is important to maintain
            their anatomical relation with the internal iliac vessels.

            In this workshop you will be taught to rotate the probe 90 degrees
            clockwise to align the marker spot on the probe handle with the direction
            of the arrow. Point the tip to the right adnexa to identify and examine the
            right tubes and ovaries. The ovary will appear medial and anterior to the
            internal iliac vessels. Its position in the pelvis, however, may be variable
            from being high and near the pelvic brim, or very low and behind the
            uterus depending on whether there are any adhesions, history of previous
            surgery or adnexal pathology. Then point the tip of the probe to the left,
            without rotating the probe , to examine the left tube and ovary. This
            will maintain the anatomical relationship of the ovary with the internal
            iliac vessels.




                                        R      L



                       Figure 10. Examination of right and left adnexae



   3        The ovaries are identified with ease in young and premenopausal women
            and appear as ellipsoid, uniformly hypoechoic structures with a regular
            outline.



               Grimsby Basic Transvaginal Ultrasound Workshop                                      11
            If examined in the early follicular phase, the ovary contains a number of
            small follicles. In the normal luteal phase, the corpus luteum is the
            hallmark of this phase. A small amount of fluid is seen in approximately
            a quarter of women after ovulation. The surrounding bowel is usually
            more echogenic and peristaltic movement is easily seen.

    4       The peri- or postmenopausal ovaries are more difficult to identify as they
            become smaller with age and do not show the follicular structures of the
            reproductive years.



USEFUL MANOEUVRES

1   Tilting/Angling the shaft

    The plane of insonation is tilted or angled to any direction in the pelvis. This is
    achieved by tilting the ultrasound transducer by its handle so as to point the tip of
    the probe in the desired direction.




                        Figure 11. Tilting of the tip of the probe




2   Pushing and pulling the probe

    This manoeuvre brings the tip of the probe closer to the region of interest,
    thereby bringing the structure in question into the focal length of the probe (focal
    zone).




              Grimsby Basic Transvaginal Ultrasound Workshop                       12
                         Figure 12. Pushing /pulling manoeuvre

3   Rotating the probe

    The handle is slowly rotated along the longitudinal axis of the probe to change
    the plane of insonation. This manoeuvre helps to build a three dimensional
    image in the sonographer's mind to assist the diagnosis. It is also used when
    measurement of follicular diameter in two different planes is required.




                            Figure 13. Rotational movement



4   Pressure on right or left iliac fossa

    Applying pressure on the right or left iliac fossa, usually by the patient, will bring
    ovaries which are high in the pelvis down and closer to the probe thus facilitating
    their visualisation.


5   Steering

    If the facility is available in the machine, electronic steering of the beam in either
    direction allows visualisation of the areas outside the field of view without the
    need to move the probe. This is useful if the ovaries or adnexal masses are
    displaced laterally or if the patient is in pain and minimal movement of the probe
    is desired.




               Grimsby Basic Transvaginal Ultrasound Workshop                         13
                              Figure 14. Electronic steering

6.    Testing for pain

      The probe can reach and touch any pelvic organ seen on the monitor and test for
      pain by watching the organ on the screen and localizing it.


REPORTING OF FINDINGS
Schematic Reporting System

1     The uterus and cervix.
             Anteverted/retroverted uterus.
             Endometrial thickness.
             Decidual reaction, gestation sac (true or pseudosac).
             Uterine cavity abnormality, fibroids, polyps, etc.
             Cervical state (closed, dilated).

2     The adnexa (tubes and ovaries).
             Hydrosalpinx
             Ovarian cysts (solid/cystic i.e. complex).
             Polycystic ovary (PCO).
             Macrocystic ovary (MCO).

3     Pouch of Douglas (cul-de-sac).
             Free fluid/clots.
             Solid masses.

4     Other pathology (bladder, pelvic kidney, etc.).




                                                                                 14
                Grimsby Basic Transvaginal Ultrasound Workshop
INTERPRETATION OF THE IMAGES

1   The Cervix

    The cervix undergoes changes during the menstrual cycle and sometimes
    echogenic shadows are seen along the cervical canal. Endocervical glands may
    also form cystic structures along the cervical canal either because of an
    inflammatory process or as a result of squamous metaplasia. These cystic
    structures may vary in size during the menstrual cycle and are simple cysts.


2   The Uterus

    The uterus is usually anteverted and, in the sagittal plane, the appearance would
    be of the bladder and the anterior wall of the uterus next to each other with
    minimal separation. If the uterus is retroverted then its anterior wall will be far
    away from the bladder and usually loops of bowel fill the space between then.
    This is an important point in the differentiation between an anteverted and
    retroverted uterus.


3   The Endometrium

    Endometrial appearance and thickness vary with the stage of the menstrual cycle.
    In the early menstrual phase an anechoic collection of blood may be seen within
    the endometrial cavity and the endometrial interphase appears as a very thin,
    echogenic line.




    Figure 15. A T-pelvic view of the pelvis showing the bladder (white arrow) and the uterus. The
    endometrial stripe (small black arrow) and the edge of the uterus (arrowhead) are clearly seen.
    The ureter is asterisked.




                                                                                             15
               Grimsby Basic Transvaginal Ultrasound Workshop
    Figure 16. An AP view of the uterus showing a late follicular endometium. The basalis layers
            (arrow) and an the endometrial stripe clearly visible. The endometrium is hypoechoic,
            which is characteritic of the follicular phase.


    Phases of Endometrium

    As the follicular phase progresses the endometrium thickens and, in the
    immediate preovulatory phase, it is between eight and ten millimetres thick.
    Three separate lines should be seen with the middle representing the endometrial
    cavity. An anechoic halo 1-2mm. thick separates the endometrium from the
    myometrium. The outline of the endometrial cavity should be regular, however,
    on occasions there are endometrial polyps or submucous fibroids that distort the
    outline. In the luteal phase the endometrium appears more echogenic and less
    thick.

    In women with amenorrhoea or infrequent periods (oligomenorrhoea) the
    endometrium may be extremely thickened to over 1.5cm. and vary in
    echogenicity. This is due to prolonged unopposed oestrogen effect. Similarly
    thickened endometrium with small cystic lesions may be seen in women who are
    postmenopausal and an Tamoxifen therapy for previous breast surgery.

    The postmenopausal endometrium is atrophic and appears as a thin, echogenic
    line measuring no more than 5mm. The surrounding subendometrial halo should
    be symmetrical and intact.

4   Early Pregnancy

    Choriodecidual thickening is seen at about 4 weeks and a gestational sac may be
    seen as early as 4½-5 weeks from the last menstrual period. The double ring
    "decidual" sign is an important feature of normal intrauterine pregnancy. The
    inner ring sign represents the chorionic sac and the outer ring is the decidualised
    endometrium. By the end of the fifth week the gestational sac and possibly fetal
    heart beats may be demonstrable without difficulty. Fetal movement is noted at
    seven weeks or later.




               Grimsby Basic Transvaginal Ultrasound Workshop                            16
    Figure 17. An AP view of a singleton gestation in a woman presenting with vaginal bleeding. An
    area of subchorionic haemorrhage is seen (black arrowhead). The fetal pole (black arrow) and
    amnion (white arrowhead) are also seen.




    Figure 18. A T-Pelvic view showing an ectopic pregnancy coexistent with an intrauterine
    pregnancy.



    Decidual thickening in the absence of the double ring sign, and if associated with
    fluid accumulation within the uterine lumen, is generally termed "pseudosac"
    and should raise the suspicion of an ectopic pregnancy. Full details of normal
    and abnormal pregnancy appearances are discussed in the lecture session.

5   Ovarian and Adnexal Appearance

    Different ovarian pathologies present with varied appearances.            Simple
    functional cysts are solitary and measure 4-7cm. in diameter. Dermoid cysts
    usually have smooth external surfaces and thin walls. The contents vary from
    low to high level echogenicity creating acoustic shadows in some areas.
    Endometriomas appear as motley echogenic and spherical lesions. More
    echogenic areas may appear in the centre of the cyst. In all ovarian lesions
    attention should be paid to the presence of septa, the number of loculi, presence
    of intracystic lesions, presence of solid areas and the appearance of




               Grimsby Basic Transvaginal Ultrasound Workshop                                 17
fluid collection in the Pouch of Douglas. Persistence of any ovarian lesion for
over 6-12 weeks requires further investigation.




  Figure 18. The left adnexal showing a 48mm x 41mm hypoechoic left ovarian cyst.




Figure 19. The right ovary showing a complex, hypoechoic mass (black arrowhead). Note the
internal septations. Cul de sac fluid (white arrowhead) is also seen. Endometrioma was revealed at
surgery.

Measurement of the ovary and estimating its volume

Measure the largest diameter (in centimetres) in the parasagittal plane (D1) and
the antero-posterior diameter (D2). In the transverse plane measure the largest
diameter in the transverse section (D3). There is no need to measure an antero-
posterior diameter in this plane. The volume is calculated from the formula of an
ellipsoid (D1 X D2 X D3 X 0.5231). Measurement of the mean follicular
diameter during superovulation is determined by calculating the average of three
or four diameters in two planes (two perpendicular measurements in the sagittal
plane and either the largest or two diameters in the coronal plane).




            Grimsby Basic Transvaginal Ultrasound Workshop                                 18
Adnexae
Abnormal and distended Fallopian tubes appear as irregular, tortuous cystic
structures with thickened walls and incomplete septa. Often they are very close
to the respective ovary. They should be differentiated from free fluid collections
in pelvic pockets of adhesions.




Figure 21. The left adnexal showing a 48mm x 41mm hypoechoic left ovarian cyst. No internal
echoes are seen and the mass represents a benign corpus liteum cyst. Note the iliac vein (arrow)
lying adjacent to the ovary. Normal compressed ovarian tissue cannot be found easily.Follow up
TV scan after menses was normal.




Figure 22. The left adnexal showing the classic “string of pearls” of a polycystic ovary. The edge
of the ovary (arrow) and multiple small ovarian follicles in the cortex are seen easily.




            Grimsby Basic Transvaginal Ultrasound Workshop                                   19
Figure 23. A T-pelvic view showing an enlarged , multicystic ovary secondary to
hyperstimulation. The entire ovary measured 11.2 X 7.2cm , and there are multiple cysts present
within the ovary.




            Grimsby Basic Transvaginal Ultrasound Workshop                               20
Grimsby Basic Transvaginal Ultrasound Workshop
CLINICAL APPLICATION

EARLY PREGNANCY SCANNING

Technique

1      Patient Preparation    -       Full bladder for transabdominal scan. Empty for
                                      transvaginal.
2      Equipment              -       Static scan more difficult to use but resolution
                                      and access to pelvic organs good.
                              -       Real-time easy to use and orientate. Sector more
                                      versatile but image often inferior to good linear
                                      array.
3      Controls               -       Gain and depth of focus (if present).
                              -       Set to give least reverberation without loss of
                                      image clarity.
4      Scan Sequence          -       Obtain uterine axis with midline scan.
                              -       Rotate 90° to obtain transverse uterine scan.
5      Landmarks              -       Bladder.
                                      Vagina.
                                      Cervix.
                                      Endometrial cavity.
                                      Ovaries.
6      Difficulties           -       Empty bladder.
       Encountered                    Scars.
                                      Malposition of uterus.

Changes in Early Pregnancy

Endometrium shows CYCLICAL CHANGES during ovarian cycle.
First signs of pregnancy are thickening and fluffiness of endometrium:
                                RING SIGN at 5/40.
                                GESTATION SAC grows rapidly.
FETAL ECHO             Appears between 6 and 7/40.
YOLK SAC                        Also seen.
FETAL HEART                     Seen to move 7-8/40.
FETAL MOVEMENTSeen 9-10/40.

BY 12 WEEKS GESTATION THE FOLLOWING SHOULD BE EVIDENT:
                     Position and shape of uterus.
                     No. of gestation sacs.
                     No. of fetuses.
                     Size of sacs and fetuses.
                     Presence of fetal heart movement (FHM) and fetal
                     movement (FM).
                     Presence of fetal poles.
                     Placentation site.
                     Hidden extras.



                  Grimsby Basic Transvaginal Ultrasound Workshop                21
DEVELOPMENTAL MILESTONE                      increase in the gain, the circular nature
                                             of the structure becomes apparent.
GESTATIONAL SAC                              Visualization of the yolk sac precedes
YOLK SAC                                     that of the embryo and its heartbeat by
EMBRYONIC HEARTBEAT                          3-7 days. The yolk sac allows more
CROWN-RUMP LENGTH                            certain diagnosis of the chorionic sac to
AMNIOTIC SAC                                 inexperienced sonographers and rules
                                             out a pseudosac, thus effectively ruling
GESTATIONAL SAC                              out ectopic pregnancy.
The chorionic sac is usually referred to
in the imaging literature as the             EMBRYONIC HEARTBEAT
gestational sac, which is not an             After the appearance of the yolk sac, the
anatomic term. The sac is the first          next reliable sign for most observers is
reliable indicator of an intrauterine        the pulsation of EHR. The embryo is
gestation (IUG), by the time of first        generally obscured by the yolk sac and
missed period (15 days post fertilization,   invisible as a distinct structure until
4 weeks LMP). It is fluid filled             around day 30 (61/2 weeks LMP).
containing the embryonic disc, amnion,       However, between days 25 and 28
yolk sac and extraembryonic coelom.          [(51/2)-6 weeks LMP)] the pulsation of
The early sac visualize before yolk sac      EHR are visible to the careful observer,
becomes evident will measure 3-5mm           using magnification and perhaps M
(inner wall/inner wall) and will grow by     mode. The HR is initially in the range of
1-2mm/day until yolk sac, embryonic          80-100 bpm below day 30 (61/2 weeks
heart beat and fetal pole become             LMP), probably represent impulse
apparent. Visualization of the chorionic     generation in the sinus venosus. HR
sac rules out ectopic pregnancy, except      increases rapidly to 160-190 bpm by
in patients who conceive after ovulation     day 47-50 (9 weeks), reflecting the
induction or assisted reproductive           growing competency of the sinoatrial
technology. The normal incidence of          node. This HR continues in this range
heterotopic     pregnancy      (1:30,000     into the second trimester, slowing then
pregnancies) may be 5-10 fold increased      to the 120-160 bpm range considered
in such patients. A normal chorionic sac     normal in obstetrics.This slowing is
carries with it a miscarriage rate of        thought       to     represent      early
11.5%.                                       parasympathetic innervation of the
                                             sinoatrial node.
YOLK SAC
The next structure visible after the         CROWN-RUMP LENGTH
gestational sac and the first reliable       This is also known as the embryonic
indication of a healthy pregnancy is the     pole, early embryonic size, and (most
yolk sac. This is generally imaged at        correctly) as the greatest embryonic
day 20-24 (5-51/2 weeks LMP) as a pair       length, the crown-rump length (CRL), is
of parenthesis located on the decidual       first noted as a small echogenic focus
basalis aspect of the chorionic sac,         between the yolk sac and decidual
perpendicular to the beam of the             basalis aspect of the chorionic sac, 3-7
transducer. With time , magnification or     days after the yolk sac is noted.




                  Grimsby Basic Transvaginal Ultrasound Workshop            22
TYPES OF ABORTION (MISCARRIAGE)

Threatened.
Inevitable:
        Complete.
        Incomplete.
        Missed.

Threatened Abortion (Miscarriage)

Incidence      - at least 1:5 pregnancies.
Timing         - 4, 8, 12, 16/weeks.
75% of threats with live fetus do well.
65% of abortions are due to chromosomal abnormalities.
Scanning these has altered management because it introduces precision into the
diagnosis by confirming or excluding the presence of a viable pregnancy in utero, thus
reducing hospitalisation time and waiting "to see what happens".

LOOK FOR: Presence of gestation sac.
          No. of sacs.
          Presence of fetus.
          No. of fetuses.
          Size of fetus.
          Movement of fetus.
          Fetal heart movement (FHM).
          Evidence of clots.
BEWARE    Apparently empty gestation sac need not exclude viable pregnancy.
          Often useful to repeat scan in one or two weeks.
          Fetus in utero does not exclude ectopic pregnancy.

               CLINICAL PICTURE OVERRIDES ULTRASOUND FINDINGS.


Blighted Ovum

Fertilization occurs but only placental tissue develops. No fetus present.
Ultrasound Findings: UTERUS             Enlarged.
                        SAC             Empty - NO FETUS.
                                        Irregular in shape, often collapsed fluid levels if
                                                 bleeding.
                                        Fails to grow on repeat scans.




                  Grimsby Basic Transvaginal Ultrasound Workshop              23
Missed Abortion (Early Fetal Demise)

Fetus dead in utero. Ultrasound findings depend on gestation of pregnancy.
EARLY          Called missed abortion.
               SFD.
               Collapsed irregular sac.
               Crumpled fetus - Apple bobbing sign.
               No FHM.
LATE           Called INTRAUTERINE DEATH.
               SFD.
               Reduced liquor.
               Disorganised fetal echo.
               No FHM.
               Spaldings sign.

Ectopic
Potentially FATAL.
Incidence:     0.3-1% of all pregnancies.
Classically 8-10/40 with PAIN but varies, especially with COILS and previous ectopic.
Ultrasound CANNOT CONFIRM ectopic unless fetus seen alive outside uterus (rare)
but can usually EXCLUDE ectopic if fetus seen inside uterus (exceptions exist).
Ultrasound Findings:          Uterus bulky.
                              No gestation sac in uterus.
                              Thick decidua ? Pseudo sac.
                              Fluid in POD.
                              Fetus alive elsewhere (rare).
                              Amorphous unilateral pelvic mass.
BEWARE         Other pelvic pathology can present as CLASSICAL ectopic, e.g.:
               Dermoid cyst.
               Bleeding corpus luteum.
               Twisted ovary.
               Do not be put off by STERILIZATION. (Even hysterectomised patients
               have had ectopics.)

CLINICAL PICTURE OVERRIDES ULTRASOUND FINDINGS.

Mole
No fetus.
PLACENTA degenerates.
HYPERPREGNANCY STATE due to excessive HCG production.
LFD BOGGY uterus.
Ultrasound Findings: SNOWSTORM/Uterine contents FULL OF HOLES.
                         Easily confused with DEGENERATING FIBROID.

Twins
Twin gestation sacs COMMONLY result in ABSORPTION of one with delivery of
SINGLETON FETUS.
MUST:See twins in 2 PLANES - some equipment can fool you.



                                                                             24
                 Grimsby Basic Transvaginal Ultrasound Workshop
GUIDANCE ON ULTRASOUND PROCEDURES IN
          EARLY PREGNANCY

     (Report by Joint Royal Colleges of Radiologists RCR
          Obstetricians and Gynaecologists RCOG)




     Grimsby Basic Transvaginal Ultrasound Workshop
                                                           25
       GUIDANCE ON ULTRASOUND
    PROCEDURES IN EARLY PREGNANCY
1    POLICY

     1.1   There should be a written policy as to the procedure to be adopted when
           early intrauterine death is suspected to minimize the chances of
           evacuating the uterus in error. Such a policy must be brought to the
           attention of all staff joining the unit.

     1.2   The written policy should state that if there is any doubt about pregnancy
           viability then delay in arranging evacuation of the uterus is essential.

     1.3   At the ultrasound examination the following should be recorded:

           1.3.1   The number of sacs and mean gestation sac diameter.
           1.3.2   The regularity of the outline of the sac.
           1.3.3   The presence of any haematoma.
           1.3.4   The presence of a yolk sac.
           1.3.5   The presence of a fetal pole.
           1.3.6   The crown rump length measurement.
           1.3.7   The presence or absence of fetal heart movements.

     1.4   Extrauterine observations should include the appearance of the ovaries,
           the presence of any ovarian cyst or any findings suggestive of an ectopic
           pregnancy, such as tubal mass or fluid in the Pouch of Douglas.

     1.5   This information should be presented in the form of a standardized report
           clearly signed and dated by the examiner. This is preferable to the
           common policy of writing emergency scan reports in the clinical records
           alone.

     1.6   When it is considered that a pregnancy is not viable the decision to
           perform an evacuation of the uterus should be made by an Obstetrician
           with appropriate experience and training.




                                                                             26
              Grimsby Basic Transvaginal Ultrasound Workshop
2   GUIDANCE

    2.1   An ultrasound scan should be transvaginal if any doubt exists. The
          following features should be noted:

          2.1.1   If the gestation sac has a mean diameter greater than 20mm., with
                  no evidence of an embryo or yolk sac, this is highly suggestive of
                  a blighted ovum.
          2.1.2   If the embryo has a crown rump length greater than 6mm., with
                  no evidence of heart pulsations, this is highly suggestive of a
                  missed abortion.

    2.2   When the mean gestation sac is less than 20mm., or the crown rump
          length is less than 6mm., a repeat examination should be performed at
          least one week later both to assess growth of the gestation sac and
          embryo and to establish whether heart activity exists.

    2.3   If the gestation sac is smaller than expected for gestational age the
          possibility of incorrect dates should always be considered, especially in
          the absence of clinical features suggestive of a threatened abortion.
          Under these circumstances a repeat scan should be arranged after a
          period of at least 7 days and be performed by experienced personnel.




            Grimsby Basic Transvaginal Ultrasound Workshop                   27
3   TRAINING

    3.1   The Clinical Directorates of both Radiology and Obstetrics should
          maintain, on a continuous basis, a register of those personnel considered
          to be adequately trained and experienced in obstetric ultrasound. We
          suggest the following personnel would be appropriate:

          3.1.1   Radiographers/midwives with the Diploma in Medical
                  Ultrasound (DMU) or equivalent training/experience.
          3.1.2   Radiologists with ultrasound training and experience as
                  recommended by The Royal College of Radiologists.
          3.1.3   Obstetricians and Radiologists who have completed the joint
                  obstetric ultrasound training scheme of The Royal College of
                  Obstetricians and Gynaecologist and The Royal College of
                  Radiologists, or alternatively who have appropriate experience
                  and training in obstetric ultrasound.

    3.2   While it is presently stipulated that Radiologists taking their Final
          Fellowship (FRCR) examination should spend at least 75 hours
          undergoing practical training in obstetric ultrasound, no such
          recommendation exists of obstetric trainees, although The Royal College
          of Obstetricians and Gynaecologists now requires that ultrasound training
          appears as a component of the training for the MRCOG.

    3.3   Training at all stages must include the technique of transvaginal
          ultrasound for the examination of first trimester pregnancies and
          emergency obstetric and gynaecological referrals.

    3.4   Personnel gaining experience in obstetric ultrasound must do so within a
          structured training scheme and under appropriate supervision.

    3.5   Only trained personnel should report on ultrasound scans.

    3.6   Tutorial instruction in radiology should include theoretical aspects of
          early pregnancy scanning, including normal physiological changes and
          appearances.

    3.7   Where the service is provided by the Department of Clinical Radiology,
          obstetric registrars should be encouraged to attend scanning sessions to
          observe the practice and learn scanning techniques. Their progress
          should be carefully monitored and their level of attainment formally
          assessed. Their attendance must be planned and their training integrated
          with other personnel in the department.

    3.8   Joint obstetric ultrasound meetings and case conferences should be held
          regularly and involve appropriate personnel for clinical educational and
          audit purposes.




            Grimsby Basic Transvaginal Ultrasound Workshop                 28
3.9    Early intrauterine death should be regarded as of equal significance to
       fetal death occurring at a later stage. Training in obstetric ultrasound
       should include consideration of the emotional aspects of early pregnancy
       loss.

       Instruction should be given as to how to deal with such a situation in the
       scanning room in a supportive and sympathetic way and to recognise
       when more detailed counselling would be appropriate.

3.10   It is important that a robust mechanism exists to deal with women who
       have suffered early pregnancy loss, and the development of good
       relationships between all professional groups likely to be involved is
       essential.




                                                                         29
         Grimsby Basic Transvaginal Ultrasound Workshop
4   EQUIPMENT

    4.1   The hospital should institute a rolling capital equipment replacement
          programme to ensure that state-of-the-art ultrasound equipment is
          provided for obstetric examinations in all appropriate locations.

    4.2   The advisability of using equipment more than five years old, unless
          upgraded, should be carefully considered.

    4.3   All equipment used for early pregnancy scanning should be provided
          with a transvaginal transducer.




            Grimsby Basic Transvaginal Ultrasound Workshop                 30
5   ORGANISATION

    5.1   Effective communication between the obstetric and radiology
          departments must be established so that appointments are properly
          arranged and clinical information reliably transmitted. Patients should
          not be used as a means of communicating information between
          departments.

    5.2   A special clinic, usually operating for five days a week, should be
          established for early pregnancy and gynaecological emergencies.
          General Practitioners should be able to refer patients to such a clinic
          directly on a daily basis. The clinic should be staffed appropriately.
          Facilities for "same day" Beta-human chorionic gonadotrophin (  bhCG)
          testing should be available in the clinic. Immediate admission for
          surgery should be possible for patients with unequivocal diagnosis of
          fetal loss or with acute conditions such as ectopic pregnancy.

    5.3   Protocols should be defined for dealing with emergency cases of
          complications of early pregnancy which present outside the normal
          working day, and it is essential that those personnel who provide the "on
          call" service in obstetric ultrasound are appropriately trained.

    5.4   All personnel must be aware of the serious emotional impact on the
          patient following the communication that intrauterine death has occurred.
          Such information should be imparted only when a definite diagnosis has
          been made by an appropriately trained person.

    5.5   Each obstetric ultrasound facility should have the services of a trained
          counsellor available for patients with early pregnancy loss. Counselling
          should take place in a quiet room away from the bustle of the diagnostic
          department. If possible the partner should be present, as it has been
          shown that this helps the patient to interpret the information from the
          doctor and avoid misunderstanding.




            Grimsby Basic Transvaginal Ultrasound Workshop                   31
NOTES ON THE QUESTION OF MEASUREMENTS WITH ULTRASOUND

TYPES OF MEASUREMENT

Measurements can be made of lengths (straight line or curvilinear), areas and volumes or
of times. These measurements can be interpreted in various ways, for example, the age
of the pregnancy or the weight of the fetus might be inferred from the measurements.
Each step in the process involves some measure of inaccuracy; consideration of the steps
involved leads to a better understanding of the limitations in the process.

STEPS INVOLVED

Consider the example of crown rump length measurement:

1      The probe is positioned to image the CORRECT section of the fetus.

2      Caliper markers are positioned at EACH END of the fetus.

3      The distance between these is READ from the display, and WRITTEN down.

4      Some INTERPRETATION is made: e.g. the CRL is compared with those of a
       normal population in order to estimate the age of the fetus, assuming that it is a
       normal fetus.

POSSIBLE SOURCES OF ERROR

1      The correct section might not be obtained through insufficient training,
               because the fetus is very mobile or because the structures are indistinct
       because         of machine maladjustment.
2      The calipers might be positioned against the wrong part of the image -again
       operator training.
       The calipers might not be correctly calibrated (different sound velocity perhaps
               - or pure misalignment).
3      The measurement is normally taken from a digital display having limited
       resolution (often to the nearest mm.)
       The reading of the measurement should provide no problem but a "flashing
       digit" can occasionally cause problems.
       Errors in writing down the measurement can occur, especially if the result is not
       retained on the screen between scans, or is not written down immediately.
4      The measurement now having been made to the best possible accuracy, is now
       used in some way. The size of the fetus is subject to Natural Biological
       Variability. This can be physiological or pathological - often the distinction
       cannot be made on a single measurement but other criteria need to be taken into
       account or a second measurement made at a subsequent time.




                 Grimsby Basic Transvaginal Ultrasound Workshop                32
RELATIVE IMPORTANCE OF THESE FACTORS

The relative importance of these factors will depend upon the parameter being measured,
but usually INTERPRETATION will prove the largest source of error.
However, the operator is unable to assess the accuracy of calibration of the machine,
unless gross errors exist - routine calibration is most important to avoid this source of
error.
Robinson and Fleming carried out a critical evaluation of CRL measurement and found,
after making three independent readings, that the average standard deviation was 1.2mm.
with a mean CRL of approximately 50mm. - a measure of the reproducibility of the
technique. They had to take into account factors such as "beam width", photographic
scale factors, velocity calibration in determining the mean values but, of course, these
did not affect the reproducibility of the technique.

STATISTICS

It is important to understand the difference between the concepts of Standard Deviation
and the Centile. The former is a statistical measure of the spread of values in a
"theoretical" population and may not be an appropriate measure for all data. The centile
notation represents a division of the actual results obtained. Thus 5% of babies DO have
weights below the 5th centile in the sample population.


PLACENTAL IMAGING

Ultrasound placentography is:
                                Easy
                                Safe
                                Accurate
                                Repeatable

It not only allows LOCALISATION but also CHARACTERISATION and VOLUME
assessment in connection with intrauterine FETAL WELFARE.

Indications include
                                Bleeding in advanced pregnancy
                                Pain
                                Malpresentation
                                Amniocentesis
                                Fetoscopy
                                IUT
                                Assessment of suspected IUGR




                                                                                  33
                 Grimsby Basic Transvaginal Ultrasound Workshop
Placental Grading

                               1st Trimester. Surrounds Gestation Sac
                               Final location depends on implantation site
Technique

                               GAIN setting important
                               ENSURE BASAL LAYER is highlighted, otherwise
                               ERRORS created when grade II will look like grade I.


BEAM Perpendicular to

 GRADE 0                                                          L/S Ratio Mature in
 GRADE I               31/40                                      65%
 GRADE II              36/40                                      87%
 GRADE III             38/40                                      90-100%
                       TERM                  5-10% III
                                              50% II
                                              40% I

       PLACENTA never uniformly aged.
       PREMATURE aging -                      Suspect INSUFFICIENCY
       INSUFFICIENT aging-                    Suspect DATES

PLACENTAL THICKENING

Thickness Decreases with Advancing Gestation:         Grade I                3.8cm
                                                      Grade II               3.6cm
                                                      Grade III              3.4cm

Significance doubtful except where diabetes, non             immune     hydrops,    rhesus
isoimmunisation and fetal abnormality suspected.

Unusually THIN placenta        ? IUGR or severe juvenile DM.

PLACENTAL AREA

Linearly throughout pregnancy in 15%.
Growth plateous after 34/40 in 85%.
Expect small placenta with IUGR.

After 150 days of pregnancy expect placental area to be:     187cm2 .




                 Grimsby Basic Transvaginal Ultrasound Workshop                    34
PLACENTAL LOCALISATION

Technique

       Bladder full but not too full.
       Gain settings.
       Sequence of scan planes.
       Note: A/P/LAT.                   Position of Leading Edge.
       Upper/Lower.                     Distance from Int. OS.
       Relation to Pres. Part.          ? Succenturate Lobes.

Difficulties
       Posterior position.
       Obesity.
       Advanced pregnancy.


PLACENTA PRAEVIA

Grades                 I       To lower segment.
               II      Into lower segment but not down to internal OS.
               III     Down to internal OS but not covering it.
               IV      Covering internal OS totally even at full dilatation.

PLACENTAL MIGRATION makes grading of placenta praevia irrelevant before 32/40
when lower segment of uterus forms.

20% of placentas are praevia 16-20/40 only 0.5% of placentas are praevia at term.




                                                                                    35
                  Grimsby Basic Transvaginal Ultrasound Workshop
                           GYNAECOLOGICAL ULTRASOUND

Gynaecological ultrasound is perhaps most easily divided into two areas:
      Problems associated with pregnancy (e.g. infertility, ectopic pregnancy, abortion
      in its various categories, and those involving masses in the female pelvis.

The description of a mass can best be outlined as in the diagram below. It is particularly
difficult to put a name to a mass unless other clinical criteria are taken into account.


                                                        adnexal
                                           unilateral   uterine
 I Location and Size                       or
                                           bilateral    pelvoabdominal*
                                                        indeterminate


                                                        homogeneous
                                                        septated
                                           cystic       solid foci
                                                        multiple cysts
                                                        multicystic


                                                        predominately cystic
 II Internal Consistency                   complex
                                                        predominately solid


                                                        mildly echogenic
                                           solid        moderately echogenic
                                                        markedly echogenic


                                                        well defined
 III Borders                                            moderately well defined
                                                        poorly defined
                                                        absent
 IV Ascites and Other Metastatic Lesions                present
                                                        suggestive



*Can be uterine or extrauterine.




                       Grimsby Basic Transvaginal Ultrasound Workshop             36
                  Criteria for Sonographic categorization of pelvic masses.

         Sonographic Differential Diagnosis of Cystic Gynaecological Pelvic Masses

 I Location                 adnexal                     pelvo-abdominal               adnexal or pelvo-
                                                                                      abdominal
II Internal Consistency     homogenous                  septated                      solid foci

III Definition of Borders   well defined                well to moderately well       well to moderately
                                                        defined                       well defined

Common                      Physiologic ovarian cyst    Mucinous cystadenoma          Dermoid cyst
                                                        (carcinoma)*
                            Serous cystadenoma*                                       Ectopic pregnancy
                            Hydrosalpinx
                            Endometrioma (s)|
Uncommon                    Dermoid cyst                Serous cystadenoma            Tubo-ovarian
                                                        (carcinoma)*                  abscess*
                            Para-ovarian cyst           Loculated lymphocele
                                                        Loculated pelvic abscess
Rare                        Lymphocele
                            Appendiceal abscess|
                            Mesenteric cyst
                            Peritoneal inclusion cyst
                            Ureterocele|



       Sonographic Differential Diagnosis of Complex Gynaecological Pelvic Masses

 I Location                 uterine               uterine             extrauterine       extrauterine
II Internal Consistency     predominantly         predominantly       predominantly      predominantly
                            cystic                solid               cystic             solid
III Definition of Borders   variable              well to             moderately         well to
                                                  moderately well     well defined       moderately
                                                  defined                                well defined

Common                      Intrauterine          Uterine             Tubo-ovarian       Degenerated or
                            pregnancy             leiomyoma*          abscess*           partially
                                                                      Ectopic            cystic solid
                                                                      pregnancy          ovarian
                                                                      Ovarian            tumour*
                                                                      cystadenoma
                                                                      (carcinoma)*
Uncommon                    Pyometrium            Uterine             Fluid-filled
                                                  leiomyosarcoma      loops of
                                                                      bowel
                            Adenomyosis           Endometrial
                                                  carcinoma*
Rare                        Invasive                                  Polycystic
                            trophoblastic                             ovaries|
                            tumour




                     Grimsby Basic Transvaginal Ultrasound Workshop                                  37
       Sonographic Differential Diagnosis of Solid Gynaecological Pelvic Masses

 I Location                 uterine                 extrauterine              indeterminate
II Internal Consistency     moderately echogenic    mildly to moderately      variable
                                                    echogenic
III Definition of Borders   well defined            moderately well defined   variable

Common                      Uterine leiomyoma*      Solid ovarian tumour*     Bowel tumours
                                                    (fibroma, teratoma,
                                                    adenocarcinoma)

Uncommon                    Endometrial carcinoma   Pedunculated leiomyoma    Lymphadenopathy|
                            or sarcoma
                            Uterine                 Lymphoma*                 Intraperitoneal fat
                            leiomyosarcoma
Rare                                                                          Retroperitoneal
                                                                              tumour
                                                                              Ectopic pelvic
                                                                              kidney




                     Grimsby Basic Transvaginal Ultrasound Workshop                       38
ULTRASOUND AND INFERTILITY                    window through which the pelvic
                                              structure may be visualised.
Transvaginal ultrasound (TVS) has             The ovaries may be small and mobile
become helpful if not essential for           and each patient may require a
monitoring natural and induced cycles.        different sized bladder to visualise
One can assess the size and number of         them satisfactorily. In 2-5% of women
developing follicles. This knowledge is       one or the other ovary is difficult to
essential for managing a cycle in the         visualise, particularly the left as it is
safest manner to maximise pregnancy           covered by sigmoid colon.
outcome and minimise complications            Using the uterus as a landmark,
such as hyperstimulation and multiple         longitudinal are performed moving the
pregnancy. It is also helpful in              transducer to the left or right until the
endometrial evaluation. The thickness         ovaries are visualised. The presence or
and the characteristics of the                absence of a follicle is then confirmed
endometrial lining will aid in                by a longitudinal scan.
determining the adequacy of treatment         Follicles may be visualised from a
and accurate timing for hCG injection.        diameter of 3-5mm. and appear as
The possibility of visualising details of     echo-free areas amidst the more
ovarian structures by ultrasound was          echogenic ovarian tissue. The follicles
first put forward by Kratochwil and his       are usually spherical but may appear
colleagues in 1972.          Since then       oblong due to the pressure from a full
Hackelóer et al have used this technique      bladder.
to monitor ovulation induction and have       Hackelóer found that from then on the
reported a good correlation between the       follicular growth was linear and the
follicular diameter and oestradiol            mean follicle diameter was 20mm.
concentrations.                               (range 18-24). Similar findings have
The ideal ultrasound machine for              been reported by several other authors.
evaluating infertility should have a TV       The cumulus oophorus can be
probe with a scan angle of at least 90-       visualised. Following ovulation one or
150 degrees that is steerable. Additional     more of the following may be
features to aid in the case of the            visualised:
examination would include a static
zoom and scan from a live and frozen          1      Disappearance of the follicle.
image. This allows for easier and more        2      Appearance of internal echoes.
accurate counting and measurement of          3      Collapse of the follicle with
follicles.                                           crenation of the edges.
Ultrasound scanning of ovarian follicles      4      Appearance of fluid in the
is now an established technique for                  Pouch of Douglas.
monitoring ovarian activity in a
magnitude of clinical conditions.             The changes in endometrium may be
                                              easily followed by ultrasound.

TECHNIQUE
Initially B scanners were used but high
resolution real-time scanning is more
commonly used. Sector scanners are
superior to linear array as the small port
of entry allows better visualisation of
the lateral pelvic walls. A full bladder is
essential as it acts as an acoustic
                                                                               39
                  Grimsby Basic Transvaginal Ultrasound Workshop
APPLICATIONS

1        Follicular tracking in patients with infertility.
2        Diagnosis of luteinised unruptured follicle syndrome.
3        Timing of artificial insemination.
4        Monitoring gonadotrophin treatment.
5        Monitoring Clomiphene citrate treatment.
6        Timing of post-coital tests, etc.
7        Diagnosis of polycystic and multicystic ovary syndrome.
8        Luteal phase defects.
9        Diagnosis of early pregnancy.
10       In-vitro fertilization.




                                                                   |27}
                                                                    40
Grimsby Basic Transvaginal Ultrasound

				
DOCUMENT INFO