Free-breathing, motion-corrected late gadolinium enhancement is robust and extends risk stratification to vulnerable patients

Abstract

Background: Routine clinical use of novel free-breathing, motion-corrected, averaged late-gadolinium-enhancement (moco-LGE) cardiovascular MR may have advantages over conventional breath-held LGE (bh-LGE), especially in vulnerable patients.

Methods and results: In 390 consecutive patients, we collected bh-LGE and moco-LGE with identical image matrix parameters. In 41 patients, bh-LGE was abandoned because of image quality issues, including 10 with myocardial infarction. When both were acquired, myocardial infarction detection was similar (McNemar test, P=0.4) with high agreement (κ=0.95). With artifact-free bh-LGE images, pixelwise myocardial infarction measures correlated highly (R(2)=0.96) without bias. Moco-LGE was faster, and image quality and diagnostic confidence were higher on blinded review (P<0.001 for all). During a median of 1.2 years, 20 heart failure hospitalizations and 18 deaths occurred. For bh-LGE, but not moco-LGE, inferior image quality and bh-LGE nonacquisition were linked to patient vulnerability confirmed by adverse outcomes (log-rank P<0.001). Moco-LGE significantly stratified risk in the full cohort (log-rank P<0.001), but bh-LGE did not (log-rank P=0.056) because a significant number of vulnerable patients did not receive bh-LGE (because of arrhythmia or inability to hold breath).

Conclusions: Myocardial infarction detection and quantification are similar between moco-LGE and bh-LGE when bh-LGE can be acquired well, but bh-LGE quality deteriorates with patient vulnerability. Acquisition time, image quality, diagnostic confidence, and the number of successfully scanned patients are superior with moco-LGE, which extends LGE-based risk stratification to include patients with vulnerability confirmed by outcomes. Moco-LGE may be suitable for routine clinical use.

Keywords: MRI; myocardial delayed enhancement; myocardial infarction.

Figure 1. Ten examples of pairs of breath held late gadolinium enhancement (bh-LGE) images and corresponding free-breathing motion-corrected late gadolinium enhancement (moco-LGE) in subjects able to breath hold successfully

Panels A-H depict myocardial infarction; panels I and J show scar in hypertrophic cardiomyopathy and nonischemic cardiomyopathy, respectively (arrows).

Figure 2. In the setting or arrhythmia or inability to breath hold, free-breathing motion-corrected late gadolinium enhancement (moco-LGE) can offer improved image quality compared to breath held late gadolinium enhancement (bh-LGE) images

The patient in panel F had no structural heart disease but did exhibit respiratory motion artifact from chest wall ghosting mimicking mid wall fibrosis on the bh-LGE image that was not present on adjacent slices or moco-LGE images.

Figure 3. We present a case where bh-LGE was not acquired due to atrial fibrillation and inability to breath hold, and moco-LGE revealed opposite results compared to other noninvasive modalities on three critical parameters: ischemia, myocardial infarction (MI), and mural thrombus

A functional 90 year old person had chest discomfort and peak troponins of 4.44 ng/mL. Regadenoson single photon emitted computed tomography (SPECT) revealed no ischemia and a moderate size MI without apparent viability in the left anterior descending artery (LAD) distribution with an apical aneurysm (panel A). Echocardiography also revealed wall motion abnormality in the LAD artery distribution and a “probable” mural thrombus (panel B). Entirely free-breathing CMR also revealed akinetic/aneurysmal wall motion in the LAD distribution. Yet, in contrast to the echocardiogram no thrombus was observed. In contrast to SPECT, no MI was observed in the anterior and anteroseptal walls, rated as entirely viable (panels C and D) using moco-LGE. Given the wall motion abnormality, preserved viability, and lack of history to support stress cardiomyopathy, cardiac catheterization was recommended. We suspected proximal LAD disease with profoundly ischemic stunned or hibernating myocardium, despite the SPECT exam. Based on the moco-LGE data as well as prior data, we predicted full functional recovery if revascularization was feasible. At catheterization, a 90% LAD lesion supplying a large amount of myocardium was stented restoring luminal patency; the procedure was complicated by a small left main dissection. The patient returned for CMR 3 months later; cines exhibited full functional recovery confirming initial LAD territory viability claims by CMR (panels C and D). A tiny apical wall motion abnormality persisted (asterisk, panels E and F). One year later, this patient enjoys a high quality of life without any cardiac complaints or events. (See supplementary material for additional case data).

Figure 4

Free-breathing motion-corrected late gadolinium enhancement (moco-LGE) images are considerably faster to acquire than conventional breath held segmented late gadolinium enhancement (bh-LGE) images in routine CMR practice (n=100).

Figure 5. When bh-LGE image quality was artifact-free, scatter plots and Bland-Altman plots show high correlation and excellent agreement across the myocardial infarction size spectrum without evidence of bias (solid and dotted lines indicate mean difference and ±1.96 SD of the differences, respectively)

Infarct mass was measured blindly from stacks of short axis images.

Figure 6. Outcomes examining incident hospitalization for heart failure or death according to bh-LGE or moco-LGE findings

Panel A reveals that vulnerable patients confirmed by their heart failure/mortality outcomes had significantly decreased image quality in proportion to their vulnerability, and those with the worst event-free survival had bh-LGE imaging abandoned altogether (n=41 of 390) by the supervising CMR physician at the time of the clinical scan (thick line). Thus, bh-LGE image quality was inversely related to patient vulnerability (log rank 16.8; p<0.001). Panel B reveals no such relationship between outcomes and moco-LGE image quality (log rank 1.4; p=0.5). Panel C reveals abnormality observed on bh-LGE (n=128 of 349) was not able to achieve statistical significance given the omission of the 41 vulnerable individuals in panel A without bh-LGE image acquisition (log rank. 3.64; p=0.056). Panel D shows that abnormality observed on moco-LGE (n=156 of 390) which included all patients significantly stratified risk on the entire sample (log rank. 6.0; p=0.014).