MRI IN PREOPERATIVE AND POSTOPERATIVE ASSESSMENT OF TRACHEAL STENOSISDUE TO PULMONARY-ARTERY SLING

Objective: To evaluate the potential of MRI in the assessment of trach eal stenosis due to tracheal or vascular malformations, 45 children wi th severe respiratory distress were examined prospectively during a pe riod of 1 year. Five of these children had tracheal stenosis due to a sling left pulmonary artery (SLPA). Materials and Methods: Magnetic re sonance examinations of the anesthetized children were performed with a 1.5 T Siemens MR imager using electrocardiographically gated T1-weig hted SE sequences in transverse and sagittal slice orientations. Slice thickness was 3 mm and each sequence was repeated after shifting the slice position by 1 mm. Monitoring during the examinations included EC G, oscillatory blood pressure, respiratory rate, and oxygen concentrat ion. Magnetic resonance findings were compared with esophagography, se lective pulmonary angiography, bronchoscopy, Doppler sonography, and s urgery. All examinations were repeated after surgical therapy to asses s the improvement in tracheal stenoses and the patency of the ligated and reimplanted left pulmonary arteries. Results: Magnetic resonance i maging clearly revealed the course of the SLPA and its topographic rel ationship to the trachea as well as the coexistence of cardiovascular and tracheobronchial or esophageal malformations. The degree and lengt h of tracheal stenoses, which were measured in the pre- and postoperat ive axial slices and graphically displayed, as well as the angles of t he right and left main stem bronchi, could be accurately determined. C onclusion: Magnetic resonance imaging in combination with bronchoscopy yielded the necessary and sufficient information for diagnosis and ai ded the surgeon in planning operative strategy and in postoperative fo llow-up.