High-resolution CT can differentiate between alloimmune and nonalloimmune lung disease early after hematopoietic cell transplantation.

Objective: The purpose of this study was to develop a simple semiquantitative high-resolution CT (HRCT) scoring system to differentiate alloimmune-mediated lung syndromes (allo-LS) from other lung diseases early after hematopoietic cell transplantation. Allo-LS should be differentiated from other abnormalities, such as infections and toxicity, because they are life threatening and require prompt and specific treatment.

Materials And Methods: In 52 pediatric hematopoietic cell transplant recipients with early symptoms of pulmonary disease, a clinical diagnosis was made by an expert physician. HRCT studies were scored by two independent radiologists for various airway and parenchyma abnormalities. HRCT scores were compared with the final clinical diagnoses.

Results: Patients with allo-LS had significantly higher HRCT severity scores for ground-glass pattern and airtrapping compared with patients with nonalloimmune disease. A combined score was constructed (the "allo-score") that appeared to have good predictive capacity for clinical allo-LS (AUC = 0.82). HRCT scoring was reproducible for all items except airway wall thickening and septal thickening.

Conclusion: A simple HRCT severity score can be helpful to differentiate allo-LS from other pulmonary complications early after hematopoietic cell transplantation.