Correlation of high-resolution CT, symptoms, and pulmonary function in patients during recovery from severe acute respiratory syndrome

Study objectives: Little is known of the nature of the recovery period after severe acute respiratory syndrome (SARS) infection. We hypothesized that structural changes of the lung might correlate with symptoms and pulmonary function. To answer this question, we correlate findings of high-resolution CT (HRCT) with dyspnea scores and results of pulmonary function tests in patients during recovery from SARS. Design: Retrospective follow-up cohort study. Setting: University hospital. Patients: Nineteen patients who recovered from SARS-related hospitalization. Measurements: The study included HRCT scores (0 to 100), dyspnea scores (1 to 4), static and dynamic lung volumes, and diffusing capacity of the lung for carbon monoxide (DLCO). Results: The interval between hospital discharge and HRCT study or functional assessment was 31.2 ± 4.8 days (range, 25 to 38 days) [mean ± SD]. All patients had HRCT abnormalities and were assigned to two groups: ground-glass opacity (GGO) only (n = 7, 36.8%) and GGO with fibrosis (GGO+F) [n = 12, 63.2%]. Most patients (16 of 19, 84.2%) had no zonal predominance. HRCT scores correlated well with dyspnea scores (r = 0.78, p < 0.01) and with a variety of pulmonary functional variables, with DLCO being the most significant (r = - 0.923, p < 0.001). Compared with the GGO group, the GGO+F group showed significantly lower FEV₁, FVC, total lung capacity, residual volume, and DLCO. Conclusions: HRCT findings correlate well with functional studies and clinical symptoms during recovery from SARS. Longer-term follow-up studies in a larger cohort of patients should be performed to investigate the clinical outcome of recovered SARS patients.