Objective: Our aim was to evaluate the development of changes on high-resolution CT (HRCT) associated with chronic pulmonary rejection.
Materials and Methods: Repeated HRCT examinations were performed 140 times on 13 consecutive lung transplant recipients during a mean observation period of 26 months. The postoperative time interval to the first detection of each chronic change on CT was calculated and compared with the onset of chronic rejection. Bronchiolitis obliterans syndrome (BOS) or the histologic diagnosis of obliterative bronchiolitis was assessed by the published criteria of the International Society for Heart and Lung Transplantation.
Results: BOS developed in eight patients, on an average, within 11.6 (±5.0) months. Histologic diagnosis was available from five patients. On HRCT, among the first identifiable chronic changes were volume contraction, decreased peripheral vascular and bronchial markings, and thickening of septal lines, all of which appeared between 7 (±5.0) and 11 (±6.8) months postoperatively. The mean interval for appearance of bronchodilatation was 12.5 (±8.7) months. Hyperlucency and mosaic phenomenon were identified, on an average, 16 (±6.3) and 21 (±7.3) months after transplantation.
Conclusion: On radiologic monitoring of lung recipients with HRCT, in addition to bronchodilatation, a special attention should be paid to the early chronic changes, including diminution of peripheral bronchovascular markings, thickening of septal lines, and volume reduction, which usually precede the establishment of the diagnosis of chronic rejection, whereas hyperlucency and mosaic phenomenon usually appear during more advanced BOS.