Clinical utility of Ga-67 pulmonary scans in the diagnosis and treatment of p. carinii pneumonitis in the setting of acquired immunodeficiency

Acquired immunodeficiency syndrome (AIDS) is a severe disorder of cellular immunity of obscure etiology. Since its original recognition in 1981 the incidence of AIDS has doubled in each of the succeeding six months. The most common causes of death in AIDS are Kaposi's sarcoma and p. carinii pneumonia (PCP). The latter is treatable if diagnosed early, and AIDS patients (pts) may suffer recurrent episodes of PCP. Since the invasive technique of fiberoptic bronchoscopy with transbronchial biopsy, brushing, and bronchialveolar lavage are necessary for diagnosis and follow-up a noninvasive method of categorizing which AIDS pts require this procedure would be most welcome. Fourteen symptomatic pts with AIDS were found to have PCP by the microscopic observation of the organism obtained from washings during fiberoptic bronchoscopy. Three had normal chest roentgenograms. Ga-67 scans of the thorax activity performed in each and pulmonary was graded 1-4 by three experienced observers (1, less than or equal to adjacent soft tissues; 2, greater than adjacent soft tissues, but less than liver; 3, equal to liver; 4, greater than liver). All scans were grades 3 or 4. After appropriate treatment 10 scans reverted to grades 1 or 2, corresponding with bronchoscopic resolution of PCP. Two pts with persistent grade 4 scans had persistent PCP at repeat bronchoscopy. Two pts died. These findings suggest that serial graded Ga scans may supplant bronchoscopy in the follow-up of treated PCP in AIDS and identify those AIDS pts with PCP resistant to conventional therapy requiring alternate therapy