CT of acquired abnormalities of the portal venous system.
Computed tomography (CT), including biphasic contrast material-enhanced helical dynamic scanning and three-dimensional CT angiography, is useful in evaluating acquired abnormalities of the portal venous system. At contrast-enhanced CT, portal venous thrombus usually manifests as low-attenuation intraluminal lesions combined with enlargement of the affected portal vein. Cavernous transformation, a masslike network of intertwined veins that provides an alternative pathway for a stenosed or occluded portal vein, is depicted as multiple, periportal vascular structures. At helical dynamic CT, arterioportal shunts manifest as early enhancement of the affected portal vein, transient hyperperfusion abnormalities with lobar or segmental distribution, or transient wedge-shaped enhancement peripheral to the tumor. In patients with portosplenic venous invasion by malignant neoplasms, peripancreatic or perigastric veins may dilate if they function as hepatopetal collateral veins. In patients with portal hypertension, a variety of hepatofugal collateral pathways can develop, including esophageal, paraesophageal, coronary gastric, inferior phrenic, paraumbilical, abdominal wall, splenorenal, gastrorenal, retrocaval, and mesocaval collateral pathways. An understanding of the varied CT appearances of acquired abnormalities of the portal venous system will allow more definitive diagnosis and help avoid false diagnosis of disease.
Ito
K
K
Department of Radiology, Yamaguchi University School of Medicine, Japan.
Higuchi
M
M
Kada
T
T
Mitchell
D G
DG
Nomura
S
S
Honjo
K
K
Fujita
T
T
Awaya
H
H
Matsumoto
T
T
Matsunaga
N
N
D003097:Collateral Circulation; D006801:Humans; D006975:Hypertension, Portal / Q000000981:diagnostic imaging / Q000209:etiology; D008642:Mesenteric Veins / Q000000981:diagnostic imaging; D009360:Neoplastic Cells, Circulating; D011168:Portal System / Q000000981:diagnostic imaging; D011169:Portal Vein / Q000000981:diagnostic imaging*; D013927:Thrombosis / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D014652:Vascular Diseases / Q000000981:diagnostic imaging