Blood flow and liver imaging.

Pyogenic hepatic abscesses: MRI findings on T1- and T2-weighted and serial gadolinium-enhanced gradient-echo images

“…Circumferential or wedge-shaped high signal intensity on T2-weighted images associated with early and persistently increased enhancement has been attributed to sinusoidal congestion as a response to adjacent inflammation (5,6). This pattern of signal intensity and enhancement change has also been observed in association with several benign and malignant focal lesions not associated with inflammation, and in these cases is usually wedge shaped as well (5,8,14,15). The main differential diagnostic considerations of hepatic abscesses are benign or malignant focal liver lesions that possess ring enhancement, including metastases, hepatocellular carcinoma, and lymphoma (8,9,16).…”

“…Early perilesional enhancement associated with isointense signal on unenhanced images may be attributed to compression or obstruction of the portal venous system, with resultant compensatorily increased hepatic arterial blood supply (13). Transiently increased enhancement related to portal vein compression is usually wedge shaped, reflecting the territory of the affected portal vein branch (13,14). Circumferential or wedge-shaped high signal intensity on T2-weighted images associated with early and persistently increased enhancement has been attributed to sinusoidal congestion as a response to adjacent inflammation (5,6).…”

Transient Hepatic Parenchymal Enhancement detected at dynamic imaging: A short instruction manual for the clinician

“…In these conditions, occlusion of the hepatic veins results in increased sinusoidal pressure and reverses the pressure gradient between the sinusoidal and portal veins. The portal vein then becomes a draining vein, causing an increase in arterial blood flow, and resulting in a functional APS [25,26]. At dynamic imaging, this appears as an enhancement of the central part of the hepatic parenchyma (centrilobular enhancement) with a mottled/marbled appearance.…”

“…When these conditions are not met, as in the case of a persistently increased arterial blood flow, the liver parenchyma undergoes metabolic changes that present as an area of hypodensity on imaging. This is likely due to the presence of oedema, fibrosis and/or depletion of hepatocytes in the underlying parenchyma [7,25,30].…”

Hepatic Infarction Complicated with Acute Pancreatitis Precisely Diagnosed with Gadoxetate Disodium-enhanced Magnetic Resonance Imaging

“…However, hepatic infarction complicated with acute pancreatitis seldom occurs because of the unique hepatic vascular configuration (6). The liver possesses a dual arterial and portal blood supply and a venous drainage system (7); moreover, a rich network of intra-and extrahepatic accessory and collateral arteries in this organ create a complex compensatory system in the event of reduced or absent blood flow (8,9).…”