Comparisons of Scintigraphy with In-111 Leukocytes and Ga-67 in the Diagnosis of Occult Sepsis

In a prospective study involving 32 patients with clinical suspicion of focal infection, the sensitivity and specificity of In-111-labeled leukocyte (In-WBC) scintigraphy were compared with those of Ga-67 scintigraphy performed 24-48 hr later. Of a total of 192 body sites studied, 26 foci of infection were diagnosed by aspiration, cultures, or chest radiographs. Indium-WBC indicated 19 (73%) true-positive (TP) and four (2.5%) false-positive (FP) foci of abnormal accretion; Ga-67 had 21 (81%) TP and 15 (9%) FP. The 7/26 (27%) false-negative (FN) In-WBC scintigrams involved infection foci of more than 2-wk duration; the 5/26 (19%) FN Ga-67 studies were in patients with infections manifested for less than 1 wk. The results of this study are useful in considering the indications of the two tracers.