HIGH-RESOLUTION CT IN THE EVALUATION OF CLINICALLY SUSPECTED PNEUMOCYSTIS-CARINII PNEUMONIA IN AIDS PATIENTS WITH NORMAL, EQUIVOCAL, OR NONSPECIFIC RADIOGRAPHIC FINDINGS

OBJECTIVE. We prospectively studied AIDS patients with a high clinical pretest probability of Pneumocystis carinii pneumonia (PCP) in whom c hest radiographic findings were normal, equivocal, or nonspecific with high-resolution CT (HRCT) to determine the incidence of PCP in these patients, to assess the diagnostic accuracy of HRCT for the presence o r absence of PCP, to evaluate the role of HRCT in patient management, and to determine the clinical outcome of all patients 1 month after ev aluation. SUBJECTS AND METHODS. AU patients were referred to the Divis ion of Pulmonary and Critical Care Medicine for diagnosis of clinicall y suspected PCP. Thirty-three patients were prospectively evaluated wi th HRCT within 24 hr of diagnostic bronchoalveolar lavage; Is other pa tients who underwent HRCT were managed according to the HRCT interpret ation and followed up clinically. All HRCT scans were independently re viewed by three chest radiologists; patchy or nodular ground-glass att enuation was considered to indicate ''possible PCP.'' RESULTS. The inc idence of PCP was 12% (6/51). The sensitivity of HRCT was 100%; specif icity, 89%; and accuracy, 90% (p < .005). We had five false-positive a nd no false-negative interpretations. Some form of ''airways disease'' (n = 23) was the single most common HRCT interpretation. CONCLUSION. HRCT may allow exclusion of PCP in patients with findings that are nor mal, equivocal, or nonspecific on chest radiographs. Empiric therapy o r immediate bronchoscopy can be avoided in many patients on the basis of the HRCT findings.