Dual radiopharmaceutical imaging in congenital asplenia syndrome.

Asplenia was suspected in one patient with combined immunodeficiency syndrome and 5 with congenital cardiac anomalies who had Howell-Jolly bodies on peripheral blood smears. 99mTc-sulfur colloid scans were equivocal for absence of the spleen. When they were compared with the 99mTc-PIPIDA hepatobiliary images, a discrepancy in organ morphology between the two scans indicated that the spleen was present, whereas similarity of the two images suggested asplenia. This procedure was useful in establishing asplenia in 4 patients and confirming the presence of a rudimentary or ectopic spleen in 2 others. Unequivocal demonstration of the spleen on the sulfur colloid scans makes the hepatobiliary study unnecessary, while unequivocal demonstration of a normal-appearing liver without splenic activity may warrant a tagged red-cell study for a more complete evaluation.