Abdominal Doppler Mastering the next level of vascular anatomy in the belly. Cindy A. Owen, RDMS, RVT

Transcription

1 Abdominal Doppler Mastering the next level of vascular anatomy in the belly Cindy A. Owen, RDMS, RVT

2 Introduction Abdominal Doppler is a tough exam Success is dependent on: Patient body habitus Patient ability to cooperate Experience Technique Up-to-date equipment

3 Patient Preparation Overnight fasting is optimal Perform study in early am to minimize bowel gas Allow small amount of water and meds

4 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

5 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

6 Mesenteric- Celiac Classic Celiac Anatomy (65-75%) 3 branches- Common Hepatic, Splenic, Left Gastric 1 st major branch of Aorta

7 Mesenteric - Celiac

8 Mesenteric- Celiac Low resistance flow pattern No significant increase in flow velocity after meal

9 Mesenteric- GDA GDA arises from CHA Courses anterior to pancreatic head Flow direction toward feet

10 Mesenteric GDA, Pancreaticoduodenal Arcades

11 Mesenteric- SMA

12 Mesenteric- SMA High resistance flow pattern in fasting state Increase in systolic and diastolic flow following meal Fasting Postprandial

13 Mesenteric- IMA

14 Mesenteric- IMA High resistance flow pattern in fasting state Increase in systolic and diastolic flow following meal

15 Mesenteric- Vascular Anomalies Replaced Hepatic Artery HA arises from SMA instead of celiac Incidence up to 40%

16 Mesenteric- Vascular Anomalies Replaced Hepatic Artery Presence of Replaced HA alters flow dynamics SMA shows increased diastolic flow proximal to the replaced HA

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

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

19 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

20 Velocity Criteria Secondary signs of Celiac stenosis found in hepatic, splenic arteries Turbulence Tardus parvus waveform

21 Velocity Criteria Secondary signs of high grade Celiac stenosis/occlusion in GDA Flow Direction

22 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 patients may be symptomatic Diaphragmatic Crura

23 Mesenteric- Celiac Compression More common- young patients (20-40 yrs) Female Thin Characteristic indentation or hooked appearance Appearance helps differentiate from atherosclerotic narrowing

24 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)

25 Mesenteric- Celiac Compression SMA rarely involved Evaluate in inspiration and expiration Evaluate with patient supine and erect Look for characteristic hooked appearance

26 Mesenteric- Celiac Compression Inspiration Expiration

27 Renal Vascular Anatomy Renal arteries arise from aorta immediately distal to SMA

28 Renal Vascular Anatomy RRA passes underneath the IVC and posterior to RRV

29 Renal Vascular Anatomy LRA courses posterior to the splenic and left renal vein

30 Renal Vascular Anatomy LRV courses between the SMA and Aorta SMA Left Renal Vein Aorta

31 Renal Vascular Anatomy Main renal artery Segmental Interlobar Interlobular Arcuate Interlobar Segmental Arcuate Interlobular

32 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

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

34 Renal- Vascular Anomalies

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

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

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

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

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

40 Patient with Multiple Vascular Anomalies

41 Patient with Multiple Vascular Anomalies

42 Doppler Technique- Achieving the Angle Anterior approach

43 Doppler Technique- Achieving the Angle Anterior approach

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

45 Doppler Technique- Achieving the Angle Flank approach for large patients

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

47 Doppler Technique- Achieving the Angle Right Decubitus approach for left renal artery

48 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

49 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

50 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)

51 Spectral Doppler Technique Make Doppler adjustments (angle correct, invert, baseline, sweep speed, PRF) before the patient suspends respiration or after freezing image.

52 Renal Artery Waveform Analysis Normal renal arteries demonstrate low resistance waveforms RI < 0.7

53 Renal Artery Waveform Analysis Normal intrarenal arteries low resistance RI is < 0.7 ESP present Rapid acceleration to peak systole (<.07s) ESP

54 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

55 Criteria for Renal Artery Stenosis Direct RAR > 3.5 PSV > cm/sec Post-stenotic turbulence

56 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:

57 Intrarenal Waveforms Normal Abnormal

58 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

59 Liver Vascular Anatomy- Hepatic Veins 3 Main hepatic veins Right Middle Left Hepatic veins are intersegmental Divide the liver into lobes and segments

60 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

61 Doppler Signatures- Hepatic Vein Hepatic veins exhibit a triphasic waveform A continuous waveform may indicate stenosis, compression

62 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

63 Doppler Signatures- Hepatic Artery Low Resistance Waveform Hepatopetal flow direction

64 Color Doppler Technique Sensitize system for low flow states Doppler Angle (access window) PRF (scale) Filter Doppler Frequency

65 Color Doppler Technique Sensitize system for low flow states Doppler Angle (access window) PRF (scale) Filter Doppler Frequency Avoid Color/Doppler invert

66 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

67 Indicators of Portal Hypertension Esophageal varices Hemorrhoids Caput Medusae (enlarged veins on anterior abdominal wall) Ascites

68 U/S Findings of Portal Hypertension Suggestive Splenomegaly (>13cm) Ascites Nodular liver surface Abnormal liver texture

69 U/S Findings of Portal Hypertension Diagnostic Enlarged PV (>13mm) Varices

70 U/S Findings of Portal Hypertension Diagnostic Enlarged PV (>13mm) Varices Portosystemic collaterals

71 U/S Findings of Portal Hypertension Diagnostic Enlarged PV (>13mm) Varices Portosystemic collaterals Hepatofugal PV flow

72 U/S Findings of Portal Hypertension Other Findings- Decreased PV flow velocity Complete or partial thrombus Cavernous transformation

73 Portosystemic Collaterals and Varices Most common portosystemic collaterals Paraumbilical Left Gastric (coronary v) Splenorenal Splenogastrorenal

74 Portosystemic Collaterals and Varices Paraumbilical Vein

75 Portosystemic Collaterals and Varices Left Gastric (Coronary) Vein

76 Portosystemic Collaterals and Varices Normal Flow Direction Abnormal Flow Direction

77 Portosystemic Collaterals and Varices Splenogastrorenal

78 Portosystemic Collaterals and Varices Gallbladder Wall Varices

79 Portosystemic Collaterals and Varices Splenic Varices

80 PV Thrombosis Etiologies Portal hypertension Hypercoagulable states Biliary atresia/cirrhosis Inflammatory process Tumor infiltration (presence of neovascularity can aid in differentiation)

81 PV Thrombosis Use Color Doppler to aid identification of PV

82 Cavernous Transformation Development of perioportal collaterals Multiple small vessels are seen in and around the occluded portal vein

83 Cavernous Transformation

84 Let s Go Scan!