Byung Ihn Choi

Contrast Enhancement in Hepatic Computed Tomography

Although it is generally agreed that intravenous administration of contrast media is necessary for imaging hepatic lesions and that bolus infusion is preferable to drip infusion, a consensus is lacking about the optimal injection protocol. Issues that remain unresolved during hepatic contrast-enhanced computed tomography (CT) include the total volume of contrast material necessary, the rate of injection of contrast material, whether the bolus should be uniphasic or biphasic, and the optimal delay between the onset of injection of contrast material and the beginning of imaging [1, 2].

Hepatic Vein Invasion by Hepatocellular Carcinoma: CT Manifestations with Anglographic Correlation

This essay illustrates the various CT findings of the hepatic venous invasion of the hepatocellular carcinoma with an angiographic correlation. The thrombosed hepatic vein is directly visualized as a dilated tubular structure or multiple nodules of the similar attenuation to that of the parenchymal tumor, connecting the parenchymal tumor and the inferior vena cava on contrast enhanced CT scans. Enhancement of the thrombosed vein on spiral CTscans obtained in early arterial phase can suggest thrombosis caused by tumor invasion rather than a simple thrombosis. When the thrombosed hepatic vein is not directly visualized and replaced bya largetumor, thetumorthrombi within the inferior vena cava or right atriu m can suggest the presence of the hepatic venous invasion.

Abdominal lymphadenopathy in tuberculosis and lymphoma:Differentiation with CT

Tuberculosis and lymphoma, these 2 diseases can present with lymphadenopathy in anywhere of the body. Therefore differentiation of tuberculosis from lymphoma is often difficul t. CT scans of 17 patients with tuberculosis and 23 patients with lymphoma were retrospectively reviewed to eva1uate the efficacy of CT scans in differentating adenopathy between tuberculosis and lymphoma. All the patients underwent abdoIIÙna1 CT scans with contrast enhancement before treatment. The size, interna1 architecture, distribution of lymph nodes , and associated findings on CT scans were ana1yzed. As compared with lymphoma, tuberculous lymphadenopathy showed 1) fema1e preponderance (65%) , 2) predilection for portocava1 1ymph nodes (47%) , 3) interna1 low attenuation in lymph nodes (82%) , 4) cold abscess formation (24%). Characteristics of lymphoma on CT scans inc1uded 1) ma1e prepondrance (78%) , 2) conglomeration of lymph nodes (39%) , 3) homogeneous interna1 1ymph node structure (83%). These results suggest that eva1uation of the characteristics of lymphadenopathy on CT scans is helpful for differentiating between tuberculosis and lymphoma.

Superselective transcather arterial embolization for hepatocellular carcinoma with a mixture of ethanol and lipiodol

To evaluate the effectiveness of superselective transcatheter arterial embolization (STAE) for hepatocelluar carcinoma (HCC) with a mixture of ethanol and Lipiodol. STAE was done in 12 male patients with HCC. Three were diagnosed clinically with angiographic findings 없ld elevated alphafetprotein levels and three were recurrent tumors after surgery. Sono-guided aspiration biopsy proved the diagnosis of hepatocellular carcinoma in another six patients. The tumor was a small single nodule (2-5cm in diameter) in 11 patients. In one patient. two nodules were found. Superselective catheterization was done using 3F Tracker catheter (Target Therapeutics USA) coaxially through 6F catheter into the feeding hepatic artery. usually the third order branch. One to four cc of 75% ethanol mixed with Lipiodol was infused under f1uoroscopy immediately after imjection of 2% Iidocaine. Immediate angiography and CT after 2 weeks were undertaken . Complete segmental or subsegmental devascularization including feeding arteries and tumor vascularities occurred in all patients. Follow-up angiography after 6 to 15 months revealed the tumor opacified by Lipiod이 . The tumor decreased in 5 cases and recurrence was found in three patients. CT taken 2 weeks after ST AE showed low density halo around the tumor in 5 cases. Subsequest segmentectomy in four patients revealed total or near total necrosis of the tumor and no evidence of damage in surrounding parenchyme. ST AE for HCC with a mixture of ethanol and Lipiodol is an effective and safe measure for small HCC.