Sixty per cent of the blood resides in veins. Despite the importance of the venous system, the easy accessibility to the arterial system has resulted in numerous publications about arteriographic findings with almost complete disregard of the descriptive appearance of the small and medium sized visceral veins. The fragile wall of visceral venules accounts for their early involvement in visceral tumors and in infiltrative processes. In some instances the visceral veins are involved primarily, or exclusively (i.e., phlebitis or hepatic veins or primary portal vein thrombosis). In other situations, such as in neoplasias, they are involved secondarily. Chest roentgenograms may reveal abnormalities secondary to abdominal visceral venous obstruction. An enlarged azygos vein, radiographic signs of pulmonary thromboembolism, and an enlarged terminal segment of the inferior vena cava may be observed secondary to processes which obstruct the hepatic veins or the inferior vena cava. Renal vein thrombosis may also cause pulmonary thromboembolic complications. Radiographic examination of the alimentary tract may reveal signs of abdominal visceral venous obstruction. Suggestive of obstruction of abdominal visceral veins are gastroesophageal varices, varices of the duodenum or small bowel, thickening of valvuli conniventi, ascites, changes in liver size, splenomegaly, internal hemorrhoids, 'thumbprinting', anterior displacement of the second part of the duodenum, and pseudocholesterolosis. Scintigraphic, and computed tomographic studies of the liver and spleen are noninvasive complementary techniques to conventional radiographic examinations, and may reveal abnormalities suggesting cirrhosis, tumor, or retroperitoneal masses.
|Original language||English (US)|
|Number of pages||24|
|Journal||Radiologic Clinics of North America|
|State||Published - Dec 1 1976|
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging