[Usefulness of ventilation and perfusion scans in patients with collagen-vascular diseases]

We studied 32 patients with collagen-vascular diseases with Xe-133 ventilation scans (V) and Tc-99m MAA perfusion scans (Q). Five patients underwent sequential studies at intervals of more than 3 months. Mean transit time (MTT) was calculated from the Xe-133 wash-out curve. V, Q images and MTT were compared with chest X-ray films and the values of %DLco. Of 32 patients, 17 had no abnormal finding on the chest X-ray films. Of the 17 patients, however, V and/or Q abnormalities were found in 10 (59%), 14 patients (82%), respectively. Every patient with abnormal findings on the chest X-ray film showed both V and Q abnormalities. Overall, Q abnormality was more frequent and severer than V one. Of the 5 patients with the sequential studies, 3 showed prolongation of MTT in concordance with deterioration of pulmonary fibrosis. V and Q abnormalities were not necessarily relevant to %DLco. In conclusion, ventilation and perfusion studies are useful in assessing the regional pulmonary function in patients with collagen-vascular diseases.