Dynamic magnetic resonance imaging in unilateral diaphragm eventration: knowledge improvement before and after plication.

ABSTRACT

BACKGROUND: The assessment before surgical plication for unilateral hemidiaphragm (HD) eventration is not clearly defined and no precise criteria exist to really understand which patient is operated with which results depending on the technique used. The goal of this study was to evaluate the place of dynamic magnetic resonance imaging (dMRI) before and after plication by developing measurement criteria. METHODS: Between 2006 and 2017, 18 patients (group1 Gp1) were operated for eventrations, 15 left-sided (Gp1L) and 3 right-sided (Gp1R). All had preoperative and postoperative evaluations including dMRI and pulmonary function tests. Five healthy volunteer subjects (group2 Gp2) had the same imaging protocol. For each HD, we measured the respiratory excursion at three fixed points (S1, S2, S3) and the height of curvature on sagittal plane. We also searched for upward paradoxical diaphragm movements. RESULTS: Before surgery, no excursion (n=13) or extremely reduced excursion (n=5) was detected on the injured HD (IHD) in Gp1. Upward paradoxical movements were identified only in Gp1L (n=6). Compared with Gp2 subjects, the healthy HD for Gp1L patients had significantly reduced excursion values at three sites S1 (P=0.038), S2 (P=0.006), and S3 (P=0.004). After plication, the decreasing height of curvature confirmed a tightening of the IHD in all patients (median value from 100 to 39.5 mm in Gp1L and 92 to 74 mm in Gp1R, P=0.0001). All upward paradoxical movements disappeared. Healthy HD excursions in Gp1L normalised their values. All those imaging improvements were correlated with postoperative improvements of dyspnoea score (P<0.0001) and vital capacity (P=0.002). CONCLUSIONS: dMRI and the standardised grid we developed not only improve the knowledge of unilateral diaphragm eventration but also permit to evaluate the quality of its surgical repair. It also demonstrates that a dysfunction of the healthy HD contralateral to eventration is possible and reversible after plication of the IHD.