High resolution computed tomography in HIV patients with suspected Pneumocystis carinii pneumonia and a normal chest radiograph

Aim: To correlate the appearances of high resolution computed tomography (HRCT) with the bronchoalveolar lavage (BAL) findings in HIV positive patients in whom there is a strong clinical suspicion of Pneumocystis carinii pneumonia (PCP) but a normal chest radiograph. Patients and Methods: The 13 patients available for analysis fulfilled the following criteria: HIV positive, CD4 count less than 200 cells per mm(3) non-productive cough or non-purulent sputum daily, documented fever above 37.5 degrees C for more than a week, dyspnoea or decreased exercise tolerance and normal chest X-ray. HRCT of the lungs was performed within 24 h of the chest radiograph, using 1 mm slice at 2 cm intervals, reconstructed using a high resolution algorithm. Bronchoalveolar lavage samples were taken for cytological examination, microscopy, culture and sensitivity. The HCRT findings were correlated with the results of BAL and clinical outcome. Results: Of the 13 patients studied, four had patchy ground-glass opacities and one also had interstitial thickening. All four proved to have PCP on BAL. None of the nine patients who were negative for PCP on BAL had ground-glass opacity or abnormalities attributable to PCP. Conclusion: In this study HRCT showed abnormalities consistent with PCP in all four patients who had PCP on BAL before there were chest radiograph abnormalities. The use of HRCT may help avoid unnecessary delay, allow early medical intervention and, if our results are confirmed by larger series, may reduce the need for bronchoscopy.