Unveiling the unreal: Comprehensive imaging review of hepatic pseudolesions

Abstract

Hepatic pseudolesions are defined as non-neoplastic focal abnormalities of the liver which can mimic or conceal true liver lesions. It is particularly common in liver due to its unique dual blood supply and the existence of multilevel anastomosis between them. Because of the recent advances in CT and MRI technology, they are being increasingly encountered in daily practice. Broadly they can be categorised in to (1) Focal parenchymal abnormalities like focal fatty change, focal fat sparing, focal confluent fibrosis, segmental hypertrophy and regenerative nodules, (2) Perfusion abnormalities which include transient hepatic parenchymal enhancement in portal vein obstruction, third inflow, intrahepatic shunts, hepatic arterial occlusion and hepatic venous obstruction, (3) Imaging pitfalls like parenchymal compression, unenhanced vessels and pseudolipoma. It is essential for the radiologists to be familiar with the typical and atypical imaging features of pseudolesions to avoid mistaking them for sinister pathologies and also to avoid overlooking underlying hidden pathologies.

Lesion or Pseudolesion? A Comprehensive Description of Perfusion-Based Liver Alterations on Contrast-Enhanced Computed Tomography and Literature Review

“…Diffusely decreased parenchymal attenuation is a nonspecific finding in acute hepatitis, 24 and a heterogeneous pattern can be seen in Budd-Chiari syndrome and passive hepatic congestion 13 . In addition, hepatic steatosis could rarely appear because multiple lesions spread throughout the liver parenchyma mimicking liver tumors and liver metastases 1,48 …”

“…Anatomically, the third inflow system can be divided into different supplies: (1) gallbladder venous drainage, (2) parabiliary venous system, 25–29 and (3) epigastric-periumbilical venous system 30,31 . Moreover, some authors have identified an aberrant drainage from the lower surface of the right diaphragmatic dome 1 …”

“…30,31 Moreover, some authors have identified an aberrant drainage from the lower surface of the right diaphragmatic dome. 1 The gallbladder has complex venous drainage; generally, the fundus and the body of the gallbladder drain directly into the liver (segment IV b and V) via short veins that connect with peripheral intrahepatic portal branches (Fig. 2).…”

“…13 In addition, hepatic steatosis could rarely appear because multiple lesions spread throughout the liver parenchyma mimicking liver tumors and liver metastases. 1,48…”

“…Psuedolesions represent an important issue for radiologists because they could be misdiagnosed as real space-occupying lesions on contrast-enhanced computed tomography (CECT). According to literature, these abnormalities of liver attenuation on CECT are the result of a perfusion imbalance within distinct blood supplies of the liver caused by vascular anatomical anomalies or injuries 1 …”