124 Delayed-enhancement MRI as a predictor of functional recovery after revascularization: results from an International Multicenter Viability Trial
KeywordsWall Motion Abnormality Chronic Coronary Artery Disease Dysfunctional Segment Standardize Imaging Protocol Segmental Wall Motion Abnormality
Several single center studies have shown that Delayed-enhancement (MRI DE-MRI) can predict functional recovery after revascularization [1, 2]. The purpose of this study was to determine the prognostic value of DE-MRI for predicting recovery of regional wall motion abnormality after revascularization in patients with chronic coronary artery disease (CAD) in a prospective, international, multi-center trial.
183 patients (167 men, age: 59.1 ± 9.7 years) with angiographically confirmed CAD and resting wall motion abnormality (WMA) scheduled for coronary bypass (n = 101) or angioplasty (n = 82) were enrolled from 9 institutions (US, Europe, and Asia) using a standardized imaging protocol. Functional and DE-MRI were performed within 30 days prior to and 5.6 ± 2.4 months after intervention.
All images were acquired on a Philips 1.5 T imager with VCG gating, and a five-element synergy cardiac coil was used for signal reception. A steady-state free precession (SSFP) sequence was used for cardiac cine imaging: TR/TE/flip: 2.7 msec/1.3 msec/65°; FOV: 320 mm, matrix: 160 × 160, slice thickness: 10 mm; slice gap: 0 mm; acquired voxel size: 2.0 × 2.0 × 10.0 mm and reconstructed voxel size: 1.3 × 1.3 × 10.0 mm; temporal resolution: 25–40 msec depending on heart rate. Cine SSFP images were acquired in the two long – axis orientations (vertical long axis and 4 chambers) and short axis orientations (10 to 12 contiguous short-axis cine SSFP images from mitral valve plane through the apex). DE-MRI images were acquired 15 minutes after administering 0.2 mmol/kg of gadolinium-chelate (OptiMARK™) in the same orientation as the cine images. The DE-MRI sequence was an inversion-recovery prepared, segmented gradient echo acquisition with the following acquisition parameters: field-of-view: 384 × 384 mm; matrix size: 256 × 256; acquired voxel size: 1.5 × 1.5 × 10 mm; 32 phase encoding steps per RR interval; TR/TE/flip: 4.6/1.9/15°; NSA: 2; acquisition time per slice: 16 RR intervals. The inversion delay time (TI) between the inversion pulse and the beginning of the data acquisition necessary to null the signal from normal myocardium was determined by the Look-Locker sequence. The data acquisition was timed to occur in diastole to minimize cardiac motion.
Cine and delayed – enhanced images were analyzed based on the model proposed by Kim R et al  in which the left ventricle was divided into 12 equiangular segments on 8 – 10 short – axis views, depending on the length of ventricle. Progressively worsening segmental WMA and increasing extent of DE were scored on a scale of 0 – 4 .
The results from the first, global, multi-center trial determined that DE-MRI is a robust predictor of functional recovery after revascularization.
This article is published under license to BioMed Central Ltd.