Doppler Patterns in Abdominal Vessels PT 2 SLIDES 28-...

Doppler Patterns in Abdominal Vessels

• Doppler ultrasound is used to assess blood flow in abdominal vessels.
• Variations in flow patterns indicate potential issues such as stenosis, occlusion, or aneurysms.

Celiac Axis

• Scan transversely for a "seagull" pattern.
• Characterized by high systolic flow and some diastolic flow.
• May exhibit spectral broadening.
• Flow remains consistent after meals.

Hepatic Artery

• Scan transversely, potentially through porta hepatis or ribs.
• Low resistance flow with significant diastolic component.
• Spectral broadening is frequently present.
• Approximately 11% of hepatic arteries arise from the superior mesenteric artery (SMA).
• Crucial to check for occlusion, a life-threatening complication, especially in heart transplant patients.

Splenic Artery

• The splenic artery is a highly turbulent and tortuous branch of the celiac trunk.
• Prone to aneurysms, particularly in patients with chronic pancreatitis.
• Doppler examination of pancreatic pseudocysts is recommended to rule out aneurysms.

Superior Mesenteric Artery (SMA)

• Scan from a sagittal plane.
• Typically high resistance in a fasting state.
• After a meal, becomes non-resistive with enhanced diastolic flow.
• Doppler analysis of SMA is used for diagnosis of stenosis or occlusion of mesenteric vessels.

Renal Artery

• Exhibits a low-resistance pattern.
• Continuous flow maintains constant perfusion to renal tissues.
• Spectral broadening is present.
• Flow attenuates as it progresses toward the periphery of the kidney.
• Difficult to diagnose native renal artery stenosis due to incomplete visualization.
• Patients with renal artery occlusion frequently develop collateral vessels. Collateral vessels may obscure the occlusion.
• Multiple renal arteries are present in a significant percentage of patients (at least 30%). Renal pelvis separation is not necessarily hydronephrosis, but may indicate prominent renal vessels.

Renal Transplants

• Normal renal arteries have turbulence at the anastomosis (connection site).
• Renal artery stenosis, occurring in about 12% of transplant patients, is characterized by distal turbulence.
• Diagnosis of renal artery occlusion is easier because only one artery supplies a transplanted kidney.

Renal Transplant Rejection

• Normal transplants display low resistance flow.
• Rejection increases resistance, leading to diminished diastolic flow.
• Pulsatility index (PI) or resistive index (RI) is used to assess and quantify the degree of resistance.
• PI<.7 signifies good perfusion, while .7 to .9 indicates potential rejection, and values greater than .9 suggest probable rejection.

Renal Veins

• Flow patterns are variable, similar to the inferior vena cava (IVC).
• May be affected by tumors or clots.
• Doppler examination is a crucial component of follow-up for transplant patients.

Inferior Vena Cava (IVC)

• IVC displays a variable waveform.
• Tumor or clots should be further evaluated.

Hepatic Veins

• Hepatic veins show variable flow patterns similar to the IVC unless impacted by Budd-Chiari syndrome.
• Budd-Chiari syndrome is thrombosis of the hepatic veins, often associated with hematologic disorders, oral contraceptives, collagen diseases, or pregnancy.
• Sonographically, hepatic veins appear small and filled with echogenic material in Budd-Chiari syndrome.

Portal Vein

• Flows toward the liver (hepatopetal) with relatively continuous, low-velocity flow.
• Its flow pattern varies with respiration.
• Thrombosis results in thrombus formation, dilated splenic and superior mesenteric veins, and usually decreased respiratory variation observed on Doppler evaluation.
• Monophasic flow directed toward the liver is observed in normal portal veins.

Cavernous Transformation of Portal Vein

• Patients with chronic portal vein obstruction have collateral vessels around the portal vein.
• Diagnostic criteria include:
  • Inability to visualize the extrahepatic portal vein.
  • Echogenic change at porta hepatis secondary to fibrosis.

Portal Hypertension

• Commonly results from intrinsic liver disease (cirrhosis or cancer), or thrombosis of the portal vein.
• Portal flow is hepatofugal (away from the liver).
• Doppler findings are: low velocity in the portal vein, patent umbilical vein, variability in flow between patients, and absence of respiratory variation.
• 2D ultrasound findings include dilated portal, splenic, and superior mesenteric veins, possible patent umbilical vein, varices (collaterals), splenomegaly with dilated vessels, reduced respiratory response, and dilated hepatic and splenic arteries. Flow reversal in the main portal vein may also be present.

This quiz explores Doppler ultrasound techniques for assessing blood flow in the abdominal vessels, focusing on the celiac axis, hepatic artery, and splenic artery. Understand the unique flow patterns and potential abnormalities like stenosis and aneurysms. Test your knowledge of Doppler ultrasound applications in abdominal assessments.