The specific diagnosis of hepatocellular carcinoma by scintigraphy. Multiple radiotracer approach

Angiosarcoma of the liver: imaging of a rare salient entity

Hepatic angiosarcomas are rare mesenchymal tumors with few case series and reports describing their imaging findings in the last two decades. The computed tomography and magnetic resonance imaging findings are variable and may appear like hemangioma at one end of the spectrum and hepatoma at the other end. The use of hepatocyte specific contrast on magnetic resonance imaging may also be insufficient in making a reliable imaging diagnosis. These tumors can easily mimic hypervascular liver cancer, atypical hemangioma or metastases. This case report highlights the imaging features of this entity and also underlines that, this tumor should always be considered as a differential diagnosis for hypervascular tumors in cirrhotic patients. The current imaging paradigms for its diagnosis are also discussed.

Correlative imaging of the liver and hepatobiliary system

Many imaging techniques can be used to assess the liver and hepatobiliary system. Each modality has individual strengths and limitations, which usually vary depending on the specific clinical situation. This review discusses several specific common clinical situations where imaging of the liver and biliary system is necessary and describes the various imaging options. Space-occupying liver lesions are discussed, and particular attention is paid to the assessment of liver metastasis, hepatoma, and incidentally discovered liver lesions such as hemangioma, adenoma, and focal nodular hyperplasia. The value of ultrasound, computed tomography, magnetic resonance imaging, and scintigraphic techniques in this patient population is described. Isolated sulfur colloid hepatic scintigraphy is not of great value in the evaluation of these patients. Therefore, this review describes in some detail the value of physiological liver scintigraphy, including gallium and iminodiacetic acid (IDA) scanning as well as dynamic flow imaging of the liver such as hepatic artery perfusion scintigraphy and tagged red cell scintigraphy. Imaging of the biliary tree also is described. The roles of ultrasound and scintigraphy are compared and contrasted as related to the diagnosis of acute cholecystitis, common duct obstruction, and postoperative complications.

Hepatocellular carcinoma imaging

Radionuclide scintigraphy can give a specific diagnosis when a hypervascular "cold" defect on colloid scans "fills in" with gallium scanning. The majority of hepatocellular carcinomas will also accumulate hepatobiliary agents especially in delayed images. Magnetic resonance imaging is superior to other modalities in providing anatomic detail, such as location and relation to vessels, needed by the surgeon in operative planning.

Dual-tracer scintigraphy and subtraction studies in the diagnosis of hepatocellular carcinoma

Dual tracer scintigraphy (DTS) (technetium 99m [99mTc] sulfur colloid and gallium 67 citrate [67 gallium citrate]) of the liver and computer subtraction studies (SS) were performed in 26 patients subsequently proven to have hepatocellular carcinoma (HCC) and 32 patients with cirrhosis and focal defects on the colloid scan, with no evidence for HCC after a complete evaluation and a 2-year follow-up period. Both DTS and SS had a sensitivity of 96% and a specificity of 90.6% for HCC. There were three false positive cases (9.4%), two of which were occult abscesses. The predictive value of a positive test was 89% and that of a negative test was 97%. The smallest tumor detected measured 2 cm in diameter and was only visualized with the SS. In the clinical setting, when HCC is suspected (a situation in which tumors are usually larger than 2 cm and the pretest probability of disease is between 20% and 60%) the DTS and SS is an excellent test for the diagnosis or exclusion of HCC. It does not appear to have a role in screening programs.