Liver Spleen Bone Marrow Imaging

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Liver Spleen Bone Marrow Imaging Powered By Docstoc
					                         Liver, Spleen, Bone Marrow Imaging

   -   Structural/Colloid Scan
          o Size of particle - ~1-1000 mu = mill microns = 1 micron
          o Structural, not functional type of imaging

Principles and Purposes
   - Diagnose accuracy of Liver-Spleen scan alone is ~75-80%; with correlated ultra
       sound and CT, the accuracy is increased.
   - Deep-seated space occupying lesions – less than 1.5 cm in size will be missed
   - Use of primarily 99mTcSc concentration by Kupffer liver cells; also spleen and
       bone marrow
   - Liver diseases change perfusion, morphology distortion, deposition irregular/non-
       uniform uptake
   - RE cells of spleen and bone marrow show increase uptake.
   - Some diseases show hepatomegaly

Indications/about
   - Differential Diagnosis of hepatomegaly vs. abdominal tumors (pushing liver
       around)
   - Pre-op liver evaluation for mets with a known primary cancer
   - Work-up of patients with diffuse liver disease:
           o Cirrhosis – degeneration of tissue, leads to fibrosis which is decrease
               function (NOT ALWAYS ALCHOL)
           o Hepatitis – inflammation of the liver, causing fever, jaundice (abnormal
               level of bilirubin in blood), abdominal pain, and weakness
                    A – (HAV) – lives in the feces in intestinal tract. Spread when
                       infected individuals don’t wash hands after using toilet, and then
                       handle food. Also by water contaminated wit raw sewage, or
                       eating raw or partially cooked shellfish harvested from water
                       contaminated with raw sewage
                    B – (HBV) – lives in blood and other body fluids. Transmitted
                       from person to person through unprotected sex, sharing needles,
                       and babies born to an infector mother.
                    C – (HCV) – primarily spread by intravenous drug users. Also
                       through sharing toothbrushes, razors, and unprotected sex.
   - Evaluate liver size, position with abnormal radiographs
   - Study patients with Ascites of unknown origin; (local for biopsy)
           o Ascites – fluid in abdomen; an accumulation of fluid in the peritoneal
               cavity, causing abdominal swelling
   - Help differentiate patients with jaundice including neonatal types (congenital-at
       birth vs. physiologic-function)
           o jaundice - Due to increase in bilirubin circulation from the biliary tree
               obstruction
   - helps in diagnosis of patients with suspected liver abscess
   -   Follow-up of patients with liver malignancy post treatment – chemo, rad, or
       resection
   -   Follow-up of patients with abscess post antibiotic treatment and post-drainage
   -   Examine patients post trauma with suspected rupture
   -   Helps differentiate right/left lobe, spleen, bone marrow
   -   Detects focal S.O.L’s (space occupying lesion) – resolution limit ~1.5 cm
   -   Abdominal trauma, ex: to spleen
   -   Evaluate therapy effects; historically to help localize biopsy sites, (ultra sound is
       better)

Patient Prep:
   - none
Concerns and Considerations:
   - No prior Barium studies with in 48 hours unless they had laxative and or
       cleansing enemas.
           o Attenuation artifacts/cold defects are seen
           o May be misinterpreted as an abnormal positive study
           o Recent chest x-ray can prove rather Barium is cleared or not
   - Recent/prior renographic Iodine contrast agents for Intra-Venous Urogram with
       delayed clearance may also show as cold defect
   - If patient had a renal contrast study, and IF the renal contrast is retained (due to
       bad kidney) this could interfere with our study, because the right kidney would
       interfere
   - Female breast may cause attenuation of the right lobe of the liver – appear as a
       crescent shaped cold area; have pt raise arms or bind breast

Method/area of Localization
  - Phagocytosis – RES cells
  - Liver – 15% Kupffer cells
  - Spleen – macrophages
  - Colloid Particle
         o ~85% of dose goes to liver
         o ~10% of dose goes to spleen
         o ~5% of does goes to bone marrow

Target/Critical Organs
   - Liver and Spleen

Camera/Collimators
   - L.E. high resolution or L.E.A.P. or G.A.P.
   - L.E. diverging
* low energy because your using 99mTc
Nuclide/Rphx.s/Dose
  - History
         o History – 198Au-colloid: colloids remain fixed in cells. Know size - ~3-
            20mu. No spleen uptake due to much smaller size.
         o 113mIn-colloid: 393KeV, Tp – 1.7hr (daughter of 113Sn)
         o 99mTc-(Sn)-phytate (soln.); reacts with blood serum calcium to form a
            colloid
  - Current
         o 99mTc-albumin colloid (trade name –Microlite), which is a micro
            aggregated albumin (or minimicrospheres)
                 Dose- 1-8 mCi for dynamics and SPECTS
                 Dose- 1-5 for planar
            99m
         o      TcIDAs (imminodiacetic acids) – hepatobiliary agents with early
            images – function agent but u could use it as structural if u get early
            images
         o 99mTc-Sn-RBC’s for hemangiomas
         o 67Ga citrate, for abscesses
         o 99mTcSC most common liver agent; remains fixed in Kupffer cells
                 Dose -3-5 mCi for static.
                 Dose- 6-12 mCi for planar statics (also says 3-6 mCi)
                 Dose- 6-10 mCi for dynamics
                 Dose – 5-10 for SPECT studies
                 Double dose if you are trying to see bone marrow, or if you want a
                    good dynamic perfusion of blood flow to the liver and spleen
  - Making SC:
         o SC reaction vial must contain
                 Sodium thiosulfate
                 Acid from syringe or with 99mTcO4 added and boiled for 5-10
                    minutes.
                 Sulfer precipitates as a colloid in suspension as 99Tc2S7
                    (technetium heptasulfide) or possibly a reduced form – 99mTcSC2.
         o After cooling the vial, buffer is added from a syringe, or B to adjust the
            pH for IV injection.
         o Gelatin is present in the vial to stabilize the colloid size formed.
                 And increase in gelatin could decrease particle size
         o The colloid is non-biodegradable with 95% of the 99Tc integrated into the
            colloid particle, with about 5% free as 99mTcO4-
         o Most colloids particles are .1mu-1000mu (1um) in size, but size is affected
            by amount of gelatin, heating time, and chemical contamination which
            then affects the bio-routing.
         o The average heating time is 5-10 min. with optimal amount of gelatin,
            then u will get particles about 100-200mu (average)
                 A slight increase in heating time (8-12min) would decrease the
                    mean size to about 10-30mu
                 Excessive heating time increased would destroy the gelatin coating
                    and the average size increases and agglutination may occur.
   -   RE:
          o Kupffer cell distribution is about 75-85% in the liver, 10-15% in the
              spleen and 5% in the bone marrow. The dose should be likewise evenly
              distributed
                   If the mean colloid size is increased – the spleen shows increased
                      uptake
                   If the mean size is decreased – B.M. shows increased uptake
                   RE: average size goes to liver, then spleen, then bone marrow
          o If 99mTc has increased alumina (Al2O3) breakthrough, then the colloid
              size will increase. Also, what will happen to bone agents w too much
              alumina, has to do with a different biorouting
                   U can tell with a strip test – the strip will turn pink
                   A size increase well beyond 1.5um, esp. >5um, then lung uptake
                      may be seen as the microaggregate particles may start o cause
                      capillary blockage.
          o Blood clearance T ½ is ~2-3 minutes, but increased clearance with
              disease. Allow 10-15 minutes for max concentration to occur, more if
              liver fx is really bad.
          o If normal size colloids are seen in lungs, this indicates severe liver disease
              with patient poor prognosis
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   -     Cr-RBC’s (tagged and denatured) for spleen scan only.




Procedure Steps
   - Dynamics
         o Helps determine if tumor has blood supply
         o Bolus injection
         o Series of ~2-3 second time interval frames/images with a multi formatter
             (film) or ~1-2 second images with a computer:
         o Dynamics may help to differentiate vascular vs. Non-vascular lesions
   - Static
         o ID – 2000cts/cm2 minimum or ~500K-1M counts with a LFOV camera
         o Lesions show up as S.O.L’s
         o You should wait about 10-15 minutes after injection, until the colloidal
             particles get phagosized
         o If they have some kind of problem like liver disease, then wait 30 minutes
   - SPECT
         o Higher doses
         o Used after u have done routine studies, but they can be used to remove
             “defects” - SPECT images with increased contrast resolution may be
             obtained to increase sensitivity and specificity
         o
   - Bone Marrow
         o Higher doses what would u use and why for an ideal bone marrow scan?
Positioning/Landmarks
    Patient may be imaged in any comfortable position
   - Always anterior (of liver and spleen) stomach may obscure spleen
   - Always posterior (of liver and spleen)
           o Left lobe visualization problem due to distance, spinal column and other
              tissue
   - Always right and left laterals
   - Optional – Obliques (at 45 degrees)
           o Defiantly obliques in trauma situations
           o RAO 45 degrees
           o LAO 45 degrees to help separate the L. Lobe from the spleen
           o LPO 45 degrees to best view for spleen or a Post. Spleen for size
              determination
   - Extra view option : Inspiration/Expiration cycle:
           o Have them hold breath for as long as they can and image. This is because
              the liver moves, and when you get images while they are holding their
              breath, you have a chance of seeing the edges better
   - A second Anterior with a marker to help size and locate actual liver (not to help
       determine shape). 2 kinds of markers
              1. A flexible strip that has holes in it at a measured distance apart to help
                  determine size. Placement- run it from the xiphoid process and around
                  the costal margin (on the other side for spleen).
                      - Most of the liver is above the diaphragm, except for a small
                          inferior portion. You won’t see the diaphragm on a scan, so if
                          you see something in that area, the Liver is either enlarged,
                          drooping, or something is pushing it down – not good.
              2. A vinyl tube filled with radioactivity at equal distances apart (usually
                  57
                    Co)

Tech./Tips/key points/pitfalls
       - mark film and patient positions
       - lead strip markers
       - need high information density (ID) ~2000 or the artifacts can look like S.O.L’s
       - anything with density can show up as artifact
       - female breast are a problem
       - motion causes unclear images
       - distortion if someone has had a liver disease and its been cured
Results/Remarks
    Normal: Activity should be evenly distributed with normal anatomy RES uptake
          o Anterior:
                 Normal size and position
                 Anatomical landmarks and inferior aspect no lower than half inch
                    below costal margin
                 Right lobe larger then left
                 Thinness of inferior aspect may lead to misinterpretation
                 GB fossa is seen in the inferior aspect of the right lobe
                 Liver is pliable, regenerative organ with structure distorted when
                    disease is present
          o Posterior
                 Left lobe shows decreased visualization due to thinness of left lobe
                    and attenuation by the vertebral bodies and other tissues and
                    organs
                 Right lobe shows a renal fossa defect and costal rib imprint
          o Right lateral
                 Shows left lobe is superimposed on anterior aspect of right lobe.
                 Spleen shows to the posterior aspect.
                 IVC and hepatic vein defect seen in the superior aspect.
                 GB fossa seen in the inferior-anterior aspect.
                 Renal fossa defect seen in the inferior posterior aspect
          o Left lateral
          o spleen is well seen in the posterior aspect, anterior aspect of the liver lobe
            seen
    Abnormal:
          o Uneven distribution with S.O.L’s on static’s (vascular)vs. dynamics
            (nonvascular) most pathology is seen as SOL’s
          o Increased uptake is seen only in rare pathologies
          o Dynamics may help to differentiate vascular vs. Non-vascular lesions
          o Assessment is relative to the uptake as observed – colloid shift
          o Subphrenic or subdiaphragmatic lesion will show as separation as a cold
            area. The diaphragm doesn’t usually show on a scan, so if u see this, it
            could be one of these lesions
   Abnormal/diseases:
      o Chronic hepatitis – may lead to cirrhosis, early fatty infiltration seen with
         hepatomegaly. Progressive left lobe enlargement, bigger than right lobe
         with increased involvement of the caudate and quadrate
              Hep acute – uniform decreased
              Hep chronic – uniform decreased
      o Cirrhosis – necrosis of tissue with fibrosis due to chronic type hepatitis
              Cirrhosis – uniform decreased
              Liver appears as bands of fibrosis and nodular areas
              End stage shows atrophy of the right lobe, hypertrophy of the left
                 lobe and minor lobes
              Portal blood flow is interfered with  portal hypertension with
                 secondary splenomegaly with 50% pseudo-SOLs
              Increased bone marrow visualization
      o Abscess – single/multiple focal decreased (from infections due to
         bacteria)
      o Primary Cancer – single focal decreased (incidence increased with
         cirrhosis)
      o Adenoma – single focal decreased (rare, from birth control; aka nodular
         hyperplasia)
      o Hemangioma – focal decreased (benign cavernous tumor Dx/99mTc-
         RBCs)
      o Cyst – one or more focal decreased (if multiple = polycystic disease)
      o Metastasis Ca – multiple focal decreased (primary from colon, lung,
         breast, renal, etc.)
      o Hepatic trauma – focal decreased (w/injury – Hematoma, laceration,
         rupture)
      o Radiation Tx – focal decreased (due to radiation injury of tissue
      o SVC obstruction – increased uptake
      o Budd-Chiari syndrome – focal uptake (from hepatic vein thrombosis)
      o IVC obstruction – focal uptake
Spleen Scan
Most effective is with 99mTcSC (liver and spleen study)
RE – RES cells distribution; mean size shift to slightly greater with slight decrease in boil
time
Indications: Evaluate spleen damage from trauma
     Differentiate LUQ masses especially near the liver left lobe vs. accessory spleen
     Size and localize the position of spleen prior to splenectomy in hyperplenism
     Visualize infiltration by Hodgkin’s, reticulum cell sarcoma, metastic melanoma
Radiopharmaceuticals for Spleen only images:
     51Cr-RBCs or 99mTc-Sn-RBCs with RBCs heat treated and denatured for slightly
        damaged for sequestration to help differentiated spleen from liver tissue
     Na51CrO4 (sodium chromate) (51Cr = 320KeV and Tp = 28days)
           o Na51CrO4 solution is for in-vitro tag with 51Cr (VI) in hexavalent state,
               and a difference in valence state makes a difference in how its actually
               used

ACD – What is it? What r we using it for? Why using ascorbic acid for in-vitro process
for tagging of RBC’s?
     ADC – acid citrate dextrose – functions as an anticoagulant. It doesn’t interfere
        with tagging process – comes with kit
     Prevents further tagging of the RBC’s; may re-inject tagged RBC’s and scan ½ to
        1 hour later

1. Costal indentation
2. Inferior vena cava
3. falciform ligament
4. Cardiac impression
5. porta nepatis
6. Gall Bladder

				
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