Indium-111-granulocyte scintigraphy in brain abscess diagnosis: limitations and pitfalls

The scintigrams and records of 28 patients referred for indium-111-granulocyte scintigraphy (111In-GS) because of a suspected brain abscess were studied retrospectively. The final diagnosis was brain abscess in 8 patients, brain tumor in 18 patients, and infarct and hematoma in 1 patient each. Five patients not on corticosteroid treatment showed intense focal 111In accumulation in abscesses, whereas an abscess patient receiving a high steroid dose showed no uptake. Two patients studied twice showed intense uptake in abscesses when not on steroid therapy or on a low dose, whereas no uptake was seen when they received high or medium doses. Weak or moderate 111In uptake was observed in nine tumors. Microscopically assessed degree of tumor granulocyte infiltration, vessel proliferation, and hemorrhage did not correlate with the outcome of 111In GS. Our results suggest that intense focal cerebral 111In uptake favors the abscess diagnosis. Abscesses may go undetected, however, in patients on high- or medium-dose steroid therapy.