Chapter 111: Vascular Imaging

Normal color and spectral Doppler imaging of the hepatic artery show a normal low-resistance waveform with a resistive index (RI) of 5.6 with continuous flow though diastole. The normal RI is 0.5 to 0.8. However, it should be noted that an increased RI is often a normal finding in the postoperative period up to 72 hours.

Axial (A), coronal (B), and sagittal (C) maximum intensity projection (MIP) images illustrate the typical normal appearance of the native inferior vena cava (IVC) (yellow arrows) and adjacent donor IVC (red arrows) with metallic clips/staples.

(A) Absent arterial signal suggestive of hepatic artery thrombosis. Contrast-enhanced computed tomography (CT) (B) and 3D reconstruction from a CT angiography (CTA) (C) show abrupt cutoff of the hepatic artery (arrows). Although Doppler ultrasound is an effective modality to diagnose hepatic artery thrombosis by showing absent arterial flow, both CT and magnetic resonance imaging (MRI) are sensitive and specific noninvasive imaging tools to confirm the diagnosis.

The source image (A) shows hepatic artery cutoff distal to the gastroduodenal artery origin (arrow). Axial (B), coronal MIP (C), and 3D (D) reconstructions nicely illustrate the typical abrupt cutoff diagnostic of hepatic artery thrombosis (arrows).

Color and spectral Doppler imaging (A) show no Doppler arterial signal. T1-weighted postcontrast (B–C), magnetic resonance cholangiopancreatography (MRCP) (D), and endoscopic retrograde cholangiopancreatography (ERCP) (E) images show progressive amputation of the thinned hepatic artery (yellow arrow), liver infarction (red arrow), and saccular biliary dilatation due to necrosis (blue arrows). Delayed hepatic artery thrombosis may develop a year after transplantation and in the acute form result in biliary ischemia and infarction resulting in strictures and leaks. Intrahepatic collateral circulation may produce similar Doppler findings to those with hepatic artery stenosis, such as a tardus parvus waveform.

Color and spectral Doppler ultrasound (A) fail to show arterial flow 1 day posttransplantation, raising concern for hepatic artery thrombosis (HAT). Digital subtraction angiography (DSA) (B–C) shows slow flow due to arterial spasm. Repeated Doppler exam 15 days later (D) reveals normal arterial signal and waveform. False-positive causes of HAT due to diminished arterial flow ...