An Analysis of Chest Wall and Diaphragm Motions in Patients With Idiopathic Scoliosis Using Dynamic Breathing MRI

Purpose: The characterization of respiratory insufficiency in scoliosis remains unclear. Although diminished respiratory motions have been recognized clinically, it is difficult to measure and to describe the motions. We studied motions of the chest wall and the diaphragm during deep breathing in patients with idiopathic scoliosis using dynamic breathing magnetic resonance imaging (BMRI).

Materials and Methods: Fast SPGR sequences were used for 18 patients with idiopathic scoliosis for 9 healthy individuals. The chest wall and diaphragm motions were evaluated dynamically using a cine-loop view and a fusion display of maximal inspiratory and expiratory images. The data was analyzed quantitatively by measuring displacements.

Results: Compared with the healthy subjects, the patients showed reduced chest wall motions, though there were no significant differences in the movements of the diaphragm. The lower chest wall movements in the X direction were 9.7±5.0 mm on the right side and 8.2±3.5 mm on the left side in scoliotic patients, and 18.0±6.1mm and 18.3±6.6mm in healthy subjects, respectively. The differences were statistically significant (P< 0.05). The upper chest wall movements in the X direction were also significantly restricted in the patient (P< 0.05).

Conclusions: Although the diaphragm motions were not reduced, the chest wall movements were restricted significantly in the patients. The main distinguishing factor in respiratory dysfunction was the limited chest wall motion in scoliotic patients. The present technique is useful for assessing respiratory mechanisms dynamically and noninvasively.