Perfusional changes in liver are seen in both CT and MR. These can be related to various causes including vascular, neoplastic, infectious, inflammatory, as well as compressive effects from extrinsic processes. Aim of this educational exhibit is to review the different presentations of perfusional liver changes on imaging, to discuss some of the common and uncommon causes, and to present valuable tips and pitfalls to avoid misdiagnosis.

Liver has blood from systemic arterial (20%) and portal venous (80%) sources. Dual blood supply makes the organ well-suitedfor contrast-enhanced imaging. Different phases of liver enhancement can be depicted with high contrast and resolution on dynamic post contrast imaging. Cases presented show common and uncommon pathologies and various causes of perfusional liver changes.

Multiple common and uncommon pathologies will be discussed: CASE 1 (Figure 2): Acute Ascending Cholangitis with perfusional changes. Transient Hepatic Attenuation Differences (THADs), which appear as focal or diffuse hyperdense areas during the hepatic arterial phase on CT, have been reported in patients with acute cholangitis. CASE 2 (Figure 3): Liver Hemangioma with associated perfusional changes. With dynamic liver imaging on CT/MRI, both benign and malignant tumours can show perfusional changes due tothe presence ofportosystemic shunts. These appear as wedge-shaped enhancement on the arterial phase,...

Radiologist should be aware of the broad potential causes of perfusional hepatic changes, including neoplastic and non-neoplastic etiologies. The radiologist, based on unique imaging findings, maybe the first to raise the suspicion for a number of significant pathologies that are difficult to otherwise diagnose based on clinical findings alone. TIPS: In liver cirrhosis, functional arterioportal shunts are difficult to recognize and there could be confusion between THADS/THIDS and HCC. Hypervascular benign and malignant tumours exhibit Steal phenomenon, showing transient hyperdensity/hyperintensity on arterial phase leading to...

S. Riaz; Hamilton/CA - nothing to disclose S. Al Duwaiki; Hamilton/CA - nothing to disclose E. Haider; Hamilton/CA - nothing to disclose A. Alabousi; Hamilton/CA - nothing to disclose Affiliation: Department of Radiology, McMaster University, St. Joseph's Healthcare, Hamilton, ON, Canada

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