Dynamic magnetic resonance imaging in assessing lung volumes, chest wall, and diaphragm motions in adolescent idiopathic scoliosis Versus normal controls

Study Design. Dynamic breath-hold (BH)- magnetic resonance (MR) imaging was used to evaluate lung function in adolescent idiopathic scoliosis (AIS). Objectives. Changes in lung volume, chest wall, and diaphragmatic motions were evaluated in AIS patients and compared with normal controls. Summary of Background Data. Little is known about whether pulmonary function impairment in AIS is related to restriction of lung volume, poor chest wall expansibility, or impaired diaphragmatic motion. This is a study on the underlying pathophysiology of the abnormal pulmonary function in AIS using the ultrafast BH-MR imaging technique. Methods. Forty-two patients with moderate to severe right thoracic scoliosis (Cobb angle, 40 degrees-98 degrees), 22 patients with mild right thoracic scoliosis (Cobb angle 10 degrees-30 degrees), and 12 healthy subjects (age ranged, 11 - 18 years; all girls) were recruited for the following assessments: 1) inspiratory, expiratory, and change in lung volume; 2) change in anteroposterior (AP) and transverse (TS) diameter of the chest wall at two levels: carina and apical vertebra level; and 3) change in diaphragmatic heights. Results. Inspiratory, expiratory lung volume and diaphragmatic heights were significantly reduced in the severe scoliosis group (P < 0.05), but the change in lung volume was not affected. There was no significant difference in the change of AP or TS diameter of the chest wall as well as diaphragmatic motions among groups. Conclusion. Impairment in lung function in AIS patients is predominantly due to restriction of lung volume.