RUQ Normal Measurements
| Structure |
Normal Value |
| Gallbladder wall |
<3 mm (fasting) |
| CBD diameter |
<6 mm; +1 mm/decade after age 70; post-cholecystectomy up to 10 mm |
| Main portal vein (MPV) |
<13 mm diameter |
| IVC |
12–17 mm |
| Hepatic artery RI |
0.55–0.70 |
Doppler Assessment — Normal vs Abnormal
| Vessel |
Normal |
Abnormal |
| Hepatic artery RI |
0.5–0.7; rapid systolic upstroke |
<0.5 = proximal stenosis or AV shunt; >0.8 = distal stenosis or rejection |
| Hepatic artery — tardus-parvus |
Absent |
Slow upstroke + low RI = proximal anastomotic stenosis |
| Portal vein |
Continuous hepatopetal flow |
Reversal = portal hypertension |
| Hepatic veins |
Triphasic phasic flow |
Loss of phasicity = outflow obstruction |
Post-Transplant Complications Timeline
| Timeframe |
Complication |
US / Doppler Findings |
| Hours–days |
Hepatic artery thrombosis (HAT) |
Absent HA Doppler signal; biliary ischemia follows; emergent re-exploration or thrombolysis; most feared early complication (~1.6–8.8%) |
| Days 0–7 |
Peritransplant hematoma |
Echogenic peritransplant fluid; expected post-op; intervention if expanding or compressive |
| Days 0–14 |
Biliary leak / biloma |
Perihepatic anechoic or complex fluid collection; ERCP or percutaneous drainage |
| Weeks 1–4 |
Portal vein thrombosis |
Absent portal flow; echogenic intraluminal thrombus; bowel edema; rare (~1–2%) |
| 1–3 months |
Hepatic artery stenosis |
Tardus-parvus pattern; RI <0.5; prolonged acceleration time (>0.08 s); responds to balloon angioplasty |
| 2 wks–6 months |
Lymphocele |
Anechoic or thinly septated peritransplant fluid; drainage if symptomatic or causing biliary obstruction |
| Months–years |
Biliary stricture |
CBD/intrahepatic ductal dilatation; anastomotic (focal, at anastomosis → ERCP) vs ischemic-type (diffuse, proximal, related to HAT → poorer prognosis) |
| Months–years |
IVC / hepatic vein stenosis |
Loss of phasic hepatic venous waveforms; IVC narrowing; Budd-Chiari pattern; venoplasty |
| Any time |
Rejection |
Elevated RI >0.8 (non-specific); biopsy required; hyperacute (hours), acute (days–weeks), chronic (months) |
Hepatic artery thrombosis (HAT) is the most feared early post-transplant complication. Absent hepatic artery Doppler signal on post-transplant surveillance = emergent call to the transplant team. Biliary ischemia follows within hours. Immediate surgical exploration or thrombolysis may be graft-saving.
Reference
McNaughton DA, Abu-Yousef MM. Doppler US of the liver made simple. RadioGraphics. 2011;31(1):161–88.
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