MAGNETIC-RESONANCE-IMAGING FINDINGS IN PULMONARY KAPOSIS-SARCOMA - A SERIES OF 10 CASES

Since chest X-ray and CT scan features of Kaposi's sarcoma (KS) are no nspecific, we wanted to test the hypothesis that the histological comp onents of this tumour and/or the associated haemorrhagic component, ma y result in a characteristic signal pattern on magnetic resonance imag ing (MRI). Thoracic MRI was performed in a prospective manner in ten p atients with acquired immune deficiency syndome (AIDS) and pulmonary K S. MRI examinations (1.5 Tesla) included Spin-echo Tl (SE-Tl), before and after gadolinium injection, as well as T2-weighted sequences (SE-T 2). For each sequence the signal intensity of lesions was measured and compared with each other as well as with the signal intensity of musc le. Results were compared to the hemosiderin content of macrophages in the bronchoalveolar lavage (BAL) in all patients and with histologica l findings in three. The results were compared to values obtained in a control group of seven patients with pneumocystis carinii pneumonia. SE-Tl showed focally increased signal intensity in the pulmonary paren chyma (n=5). Signal enhancement in parenchymal lesions (n-10) and alon g peribronchovascular trees (n=5) was observed after gadolinium inject ion. The second echo of SE-T2 showed a markedly reduced signal intensi ty in pathologic areas (n-10). This last finding was not observed in t he control group. In conclusion, we have identified a pattern of MRI s ignal abnormalities suggestive of Kaposi's sarcoma. The MRI signal int ensity of KS lesions may be related to the angiomatous and fibrous com ponents of the tumour. A correlation between hemosiderin deposits and signal intensity was not demonstrated in this study, perhaps because o f a poor correlation between BAL results and the actual occurrence of an haemorragic component in parenchymal lesions.