TECHNETIUM-99M-DTPA-GALACTOSYL HUMAN SERUM-ALBUMIN LIVER SCINTIGRAPHYEVALUATION OF REGIONAL CT MRI ATTENUATION/SIGNAL INTENSITY DIFFERENCES/

Regional attenuation/signal intensity differences seen on CT/magnetic resonance imaging can be a clue in detecting regional hepatic blood fl ow abnormality. Sometimes, however, they can be misinterpreted as a he patic neoplasm or, in the case of a true neoplasm, they can lead to an overestimation of its size because these regions often have similar a ttenuation or signal intensity to hepatic neoplasms. We evaluated Tc-9 9m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin ( Tc-99m-DTPA-GSA) liver scintigrams in patients manifesting regional at tenuation/signal intensity differences to further analyze the findings . Methods: Technetium-99m-DTPA-GSA scintigrams of 23 patients with reg ional attenuation/signal intensity differences in the liver at dynamic contrast-enhanced CT/magnetic resonance imaging were evaluated. The c auses of the differences were arterioportal (AP) shunts in seven patie nts, decreases in the portal venous flow in seven patients, occlusion of right hepatic vein in one patient, confluent hepatic fibrosis in on e patient and unknown in seven patients. The accumulation of Tc-99m-DT PA-GSA was compared with each known cause of attenuation/signal intens ity difference. Count ratios of the regions to normal hepatic parenchy ma also were calculated in all cases, Results: In AP shunts, none of s even patients showed any decreased accumulation in the region. Accumul ation of Tc-99m-DTPA-GSA decreased in six of seven patients who had de creases in portal venous flow, this incidence was significantly higher than that in patients who had AP shunts (p < 0.005), In cases of unkn own cause, two of seven patients showed a decrease in accumulation, bu t the other five showed no such decrease. The one patient with occlusi on of the right hepatic vein showed no decrease, but the confluent hep atic fibrosis showed a significant decrease. The count ratio in AP shu nts was significantly larger than that of the decrease in the portal v enous flow (p < 0.005). Conclusion: Technetium99m-DTPA-GSA accumulatio n in AP shunts has a different pattern from that found in patients wit h a decrease in portal venous flow. Therefore, differentiation between AP shunts, which showed no decrease in Tc-99m-DTPA-GSA accumulation, and hepatic neoplasms can be made more easily.