What are the ultrasound features of an arteriovenous fistula (AVF)? An AVF can occur anywhere in the body but most commonly occurs in the groin following arterial puncture of the femoral artery for a cardiac catheterization procedure or in the kidney following renal biopsy. Direct visualization of the fistula may be difficult, and therefore diagnosis …
When and how should Ultrasound be used to evaluate a transjugular intrahepatic portosystemic shunt (TIPS)? Color spectral Doppler US is the initial study of choice for evaluating a TIPS used to treat portal hypertension. The TIPS procedure consists of placing a stent between the higher pressure portal system and the lower pressure hepatic veins. A …
What various vascular complications can be detected with color spectral Doppler imaging of the liver? Similar to renal transplants, US is commonly the first study of choice for detecting vascular complications following liver transplantation. US can detect hepatic artery stenosis as a PSV >200 to 300 cm/sec in the artery. More distally, an intrahepatic tardus parvus …
Normal hepatic spectral Doppler waveforms The normal hepatic artery has a rapid systolic upstroke and continuous diastolic flow. The normal portal veins have continuous hepatopedal (toward the liver) flow with mild phasicity due to respiratory and cardiac activity. Normal portal vein velocity is approximately 20 cm/sec. Due to proximity to the heart, the normal hepatic veins …
What is the role of vascular Ultrasound in evaluating renal transplants? US with color spectral Doppler imaging is the preferred initial study of choice for screening transplanted kidneys for vascular complications, as potentially nephrotoxic contrast agents are not required as in the case of CT or MR imaging. In addition to detecting main RAS in …
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Normal hepatic spectral Doppler waveforms The normal hepatic artery has a rapid systolic upstroke and continuous diastolic flow. The normal portal veins have continuous hepatopedal (toward the liver) flow with mild phasicity due to respiratory and cardiac activity. Normal portal vein velocity is approximately 20 cm/sec. Due to proximity to the heart, the normal hepatic veins …
What is the role of Ultrasound in diagnosing renovascular hypertension? Patients with difficult to control severe hypertension are the group most likely to have hypertension on the basis of main renal artery stenosis (RAS). RAS only accounts for up to 5% of all patients with hypertension but is a potentially curable cause of hypertension. US …
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