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					Abdominal Doppler
Mastering the next level of vascular anatomy in the belly



                           Cindy A. Owen, RDMS, RVT
 Introduction
• Abdominal Doppler is
  a tough exam
• Success is dependent
  on:
  – Patient body habitus
  – Patient ability to
    cooperate
  – Experience
  – Technique
  – Up-to-date equipment
 Patient Preparation
• Overnight fasting is optimal
• Perform study in early am to minimize bowel
  gas
• Allow small amount of water and meds
 Introduction
• Mesenteric Doppler performed for
  chronic condition
• Presentation:
   –   Weight loss (food fear)
   –   Post-prandial pain (10-30”)
   –   Diarrhea
   –   Abdominal bruit
   –   Most asymptomatic due to extensive
       collateral circulation (wandering
       collateral artery of Riolan)
• Coexisting Conditions
   –   Diabetes
   –   + Tobacco
   –   Generalized Atherosclerotic disease
   –   Female
• Doppler
   – Aorta, Celiac, SMA and IMA
   – At least 2 of the 3 mesenteric vessels
     must be compromised for symptoms
     to be attributed to mesenteric
     ischemia
 Technical Aspects
• Equipment
   – In thin patients linear array tx
     may provide improved
     visualization and steering
   – Up-to-date equipment
       •   PRF adequate to limit aliasing
       •   Color sensitivity
       •   Flash suppression
       •   Imaging enhancements
• Acoustic windows
   – Use left lobe liver
   – Oblique approaches
   – Semi-upright position
 Mesenteric- Celiac
• Classic Celiac Anatomy
  (65-75%)
  – 3 branches- Common
    Hepatic, Splenic, Left
    Gastric
  – 1st major branch of
    Aorta
Mesenteric - Celiac
 Mesenteric- Celiac
• Low resistance flow pattern
• No significant increase in flow velocity after
  meal
 Mesenteric- GDA
• GDA arises from CHA
• Courses anterior to
  pancreatic head
• Flow direction toward
  feet
Mesenteric – GDA,
Pancreaticoduodenal Arcades
Mesenteric- SMA
 Mesenteric- SMA
• High resistance flow pattern in fasting
  state
• Increase in systolic and diastolic flow
  following meal




     Fasting                    Postprandial
Mesenteric- IMA
 Mesenteric- IMA
• High resistance flow pattern in fasting
  state
• Increase in systolic and diastolic flow
  following meal
 Mesenteric- Vascular Anomalies
• Replaced Hepatic Artery
  – HA arises from SMA instead of celiac
  – Incidence up to 40%
 Mesenteric- Vascular Anomalies
• Replaced Hepatic Artery
  – Presence of Replaced HA alters flow dynamics
  – SMA shows increased diastolic flow proximal to the
    replaced HA
    Mesenteric- Vascular Anomalies
•   Origin of hepatic and splenic arteries from SMA
•   Absence of Celiac trunk
•   Altered flow dynamics with some anomalies
•   Others….




                 Incidence < 1 %
    Mesenteric- Vascular Anomalies
•   Origin of hepatic and splenic arteries from SMA
•   Absence of Celiac trunk
•   Altered flow dynamics with some anomalies
•   Others….




                 Incidence < 1 %
             Velocity Criteria
           • Stenosis 70% or greater
                 – Celiac systolic velocity >
                   200 cm/sec, diastolic
                   velocity > 100 cm/sec
                 – SMA systolic velocity >
                   275 cm/sec, diastolic
                   velocity >70 cm/sec
                 – IMA no specific velocity
                   criteria
                 – All Vessels
                      • Focal increase in velocity
                        with post-stenotic
                        turbulence


* Moneta GL, Yeager RA, Dalman R, et al. Duplex
ultrasound criteria for diagnosis of splanchnic artery
stenosis or occlusion J Vasc Surg 1991:14:511-8
Velocity Criteria
 – Secondary signs of Celiac stenosis found in hepatic,
   splenic arteries
    • Turbulence
    • Tardus parvus waveform
Velocity Criteria
 – Secondary signs of high grade Celiac
   stenosis/occlusion in GDA
    • Flow Direction
 Mesenteric- Celiac Compression
• Diaphragmatic crura arise
  from vertebral bodies on
  each side
• Crura
   – pass superior/anterior to
     surround aortic opening
   – joined together by the
     median arcuate ligament
     at the aortic hiatus
• Ligament usually superior to
  origin of celiac
• 10-24% Ligament is low,
  crossing over proximal celiac
• Small subset of these           Diaphragmatic Crura
  patients may be
  symptomatic
 Mesenteric- Celiac Compression
• More common-
   – young patients
     (20- 40 yrs)
   – Female
   – Thin
• Characteristic
  indentation or
  hooked appearance
• Appearance helps
  differentiate from
  atherosclerotic
  narrowing
 Mesenteric- Celiac Compression
• Compression less apparent
  during inspiration
    – Lungs expand, celiac has a
      more caudal orientation
• Compression less with upright
  position
• Severe compression will persist
  during inspiration and must be
  correlated with symptoms
• Post-stenotic dilatation may be
  present with severe
  compression
• Collateralization can occur from
  SMA through
  pancreaticoduodenal arcade
  (look for retrograde GDA)
 Mesenteric- Celiac Compression
• SMA rarely involved
• Evaluate in
  inspiration and
  expiration
• Evaluate with patient
  supine and erect
• Look for
  characteristic
  “hooked” appearance
 Mesenteric- Celiac Compression




Inspiration         Expiration
 Renal Vascular Anatomy
• Renal arteries arise from aorta immediately
  distal to SMA
 Renal Vascular Anatomy
• RRA passes underneath the IVC and
  posterior to RRV
 Renal Vascular Anatomy
• LRA courses posterior to the splenic and left
  renal vein
 Renal Vascular Anatomy
• LRV courses between the SMA and Aorta




                               SMA
                                     Left Renal Vein
                                     Aorta
Renal Vascular Anatomy
Main renal artery

  Segmental              Interlobular
                     Arcuate
                       Interlobar
  Interlobar
                         Segmental

   Arcuate

  Interlobular
 Renal- Vascular Anomalies
• Supernumery renal arteries
  – Occurs in approximately 30% of population
  – May be unilateral or bilateral
  – Usually arise from abdominal aorta, but may
    arise from CIA, IMA, Adrenal or RHA




             Check Posterior to IVC
Renal- Vascular Anomalies




  Check aorta in both transverse and
  coronal view using color Doppler
Renal- Vascular Anomalies
Renal- Vascular Anomalies




Early Bifurcation- 15% of population- can affect
laparoscopic surgery for donor kidney
Renal- Vascular Anomalies




Precaval RRA- 0.8 – 5% of population,
Often associated with horseshoe and
malrotated kidneys and UPJ obstruction
Renal- Vascular Anomalies




Retroaortic LRV- up to 3 % of population
Renal- Vascular Anomalies




  Circumaortic LRV- up to 9% of population
Renal- Vascular Anomalies




  Circumaortic LRV- up to 9% of population
Patient with Multiple Vascular
Anomalies
Patient with Multiple Vascular
Anomalies
Doppler Technique- Achieving the
Angle




       Anterior approach
Doppler Technique- Achieving the
Angle




       Anterior approach
Doppler Technique- Achieving the
Angle




    Flank approach for renal
    artery origins and aorta
Doppler Technique- Achieving the
Angle




 Flank approach for large patients
Doppler Technique- Achieving the
Angle




       Oblique approach
       for right renal artery
Doppler Technique- Achieving the
Angle




   Right Decubitus approach for
   left renal artery
 Doppler Technique- Intrarenal Arteries
• Roll patient into decubitus position
• Scan along posterior axillary line
• Should have very little, if any, liver or spleen
  in image




     Incorrect                      Correct
 Doppler Technique- Intrarenal Arteries
• Intrarenal Doppler
  Technique
  – Sweep Speed of 2 -3
    seconds
  – PRF set for waveform
    to fill window
  – Large Sample
    Volume Size
  – Low Wall Filter
  – High Doppler
    frequency
  – Angle must be < 30
    degrees
Spectral Doppler Technique
              Beavers can hold their
              breath for an average of
              45 minutes

                       But….

              Humans can only hold
              their breath for an
              average of 1 minute---
              (the world record is 7.5
              minutes)
Spectral Doppler Technique




Make Doppler adjustments (angle
correct, invert, baseline, sweep speed,
PRF) before the patient suspends
respiration or after freezing image.
 Renal Artery Waveform Analysis
• Normal renal arteries demonstrate low
  resistance waveforms
• RI < 0.7
 Renal Artery Waveform Analysis
• Normal intrarenal arteries
   –   low resistance
   –   RI is < 0.7
   –   ESP present
   –   Rapid acceleration to peak systole (< .07s)




                      ESP
 Two Doppler Methods for Detecting
 Renal Artery Stenosis
• Direct Evaluation
  – Direct visualization
    with Doppler
    throughout the Main
    renal artery and all
    accessory renal
    arteries
• Indirect Evaluation
  – Doppler of the
    segmental/interlobar
    renal arteries at the
    upper, mid and lower
    renal poles
 Criteria for Renal Artery Stenosis
• Direct
  – RAR > 3.5
  – PSV > 180-200 cm/sec
  – Post-stenotic turbulence
 Criteria for Renal Artery Stenosis
• Indirect
  – Absence of ESP (most sensitive criterion) *
  – Tardus Parvus shape
  – Delayed acceleration time (AT > .07 sec)
  – RI difference between kidneys exceeding -5




        * Stavros, et al. Ultrasound Quarterly 1994;12: 217-263
Intrarenal Waveforms




    Normal             Abnormal
 “How To” Protocol for Renal Doppler
• Quick survey on each side
   – Check for visibility of main renal arteries,
     accessory renal arteries
   – Check for AAA
• Direct interrogation of both renal arteries
   – Obtain RAR for both renal arteries
• Indirect interrogation of upper, mid and lower
  poles of both renal arteries
   – If RI > 0.75 or AAA present, discontinue indirect
     exam
 Liver Vascular Anatomy- Hepatic
 Veins
• 3 Main hepatic veins
  – Right
  – Middle
  – Left
• Hepatic veins are
  intersegmental
  – Divide the liver into
    lobes and segments
 Liver Vascular Anatomy- Portal
 Vein
• Begins at junction of
  SV and SMV
• Courses superiorly
  and to the right toward
  porta hepatis
• Portal triad-
   – Portal vein, hepatic
     artery and bile duct
• Portal veins are
  intrasegmental
 Doppler Signatures- Hepatic Vein
• Hepatic veins exhibit a triphasic waveform




• A continuous waveform may indicate
  stenosis, compression
 Doppler Signatures- Portal Vein
• Portal veins exhibit a low velocity,
  monophasic signal with subtle phasicity
• Flow direction toward liver (hepatopetal)
• Pulsatility may indicate increased right
  heart pressure due to CHF, tricuspid
  insufficiency
Doppler Signatures- Hepatic Artery
• Low Resistance
  Waveform
• Hepatopetal flow
  direction
 Color Doppler Technique
• Sensitize system for
  low flow states
  – Doppler Angle
    (access window)
  – PRF (scale)
  – Filter
  – Doppler Frequency
 Color Doppler Technique
• Sensitize system for
  low flow states
  – Doppler Angle
    (access window)
  – PRF (scale)
  – Filter
  – Doppler Frequency
• Avoid Color/Doppler
  invert
 What is Portal Hypertension
• Increase in portal vein
  pressure due to
  anatomic or functional
  obstruction to blood flow
  in the portal venous
  system
   – Normal range 2-6
     mmHg
   – Formation of varices
     >10 mmHg
   – Variceal bleeding >12
     mmHg
• Etiologies divided into
  Prehepatic, intrahepatic
  and posthepatic with
  most common being
  intrahepatic chronic liver
  parenchymal disease
 Indicators of Portal Hypertension
• Esophageal varices
• Hemorrhoids
• Caput Medusae
  (enlarged veins on
  anterior abdominal
  wall)
• Ascites
 U/S Findings of Portal
 Hypertension
• Suggestive
  – Splenomegaly
    (>13cm)
  – Ascites
  – Nodular liver
    surface
  – Abnormal liver
    texture
 U/S Findings of Portal
 Hypertension
• Diagnostic
  – Enlarged PV (>13mm)
  – Varices
 U/S Findings of Portal
 Hypertension
• Diagnostic
  – Enlarged PV (>13mm)
  – Varices
  – Portosystemic collaterals
 U/S Findings of Portal
 Hypertension
• Diagnostic
  – Enlarged PV (>13mm)
  – Varices
  – Portosystemic collaterals
  – Hepatofugal PV flow
       U/S Findings of Portal
       Hypertension
• Other Findings-
  – Decreased PV flow velocity
  – Complete or partial thrombus
  – Cavernous transformation
 Portosystemic Collaterals and
 Varices
• Most common portosystemic collaterals
  –   Paraumbilical
  –   Left Gastric (coronary v)
  –   Splenorenal
  –   Splenogastrorenal
  Portosystemic Collaterals and
  Varices




Paraumbilical Vein
 Portosystemic Collaterals and
 Varices
Left Gastric (Coronary) Vein
  Portosystemic Collaterals and
  Varices




Normal Flow Direction   Abnormal Flow Direction
      Portosystemic Collaterals and
      Varices
Splenogastrorenal
      Portosystemic Collaterals and
      Varices
Gallbladder Wall Varices
      Portosystemic Collaterals and
      Varices
Splenic Varices
PV Thrombosis
• Etiologies
   – Portal
     hypertension
   – Hypercoagulable
     states
   – Biliary
     atresia/cirrhosis
   – Inflammatory
     process
   – Tumor infiltration
     (presence of
     neovascularity can
     aid in
     differentiation)
 PV Thrombosis
• Use Color Doppler to aid identification of
  PV
 Cavernous Transformation
• Development of
  perioportal collaterals
   – Multiple small vessels
     are seen in and
     around the occluded
     portal vein
Cavernous Transformation
Let’s Go Scan!

				
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posted:11/13/2011
language:English
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