Young, Phillip M.

Abstract Background Heart transplant (HTx) patients can develop graft dysfunction (GD) without biopsy evidence of cell or antibody mediated rejection. Cardiac MRI (CMR) can detect inflammatory or infiltrative causes of cardiomyopathy however CMR findings in HTx recipients with GD have not been previously described. Purpose We sought to identify CMR characteristics of HTx patients with GD, and evaluate its additive value in its diagnosis and prognosis. Methods CMR has been performed routinely to evaluate GD at our institutions. There were 37 HTx recipients who presented with acute decline in left ventricular ejection fraction (LVEF) of <50% and >10% from baseline, with no biopsy evidence of rejection between 2007 and 2018. Coronary angiogram with IVUS was done to rule out allograft vasculopathy. Treatment of GD was per discretion of the treating clinician. Responders were defined as those with LVEF improvement >10% at 180 days or greater post-presentation. LV and RV indices, the presence and pattern of late gadolinium enhancement (LGE) were determined by CMR. Results There were 34% females and mean age at transplant was 49±13 years. Median time from HTx to GD was 1.2 years. Presenting symptoms were heart failure (n=25), cardiogenic shock (n=1) and 11 patients were asymptomatic. Mean LVEF at presentation was 37±12% and donor specific antibodies were detected in 38% patients. Most patients were treated with steroid bolus (n=29), and/or plasmapheresis (n=23). There were no major changes made in immunosuppression in 6 patients. Delayed enhancement MRI was performed with standard inversion-recovery (IR) gradient echo sequences, between 5 and 20 minutes after institutional-standard protocol administration of IV gadolinium contrast. Biventricular LGE was present in 18/37 (49%) patients with GD and was more prevalent in responders (57%, 13 of 23) than non-responders (35%, 5 of 14), although not statistically significant (p=0.21). There were two patterns of LGE noted: 1) Diffuse epicardial (10 patients out which 9 were responders) and 2) Patchy pattern with non-specific distribution (8 patients out of which 4 were responders). Myocardial edema by triple IR sequencing was seen in 6 patients, all having diffuse epicardial pattern of enhancement matching the delayed enhancement pattern. When comparing different treatment groups, among those treated for GD (n=31), 12 of 21 (57%) responders had LGE and 4 of 10 (40%) non-responders had LGE (p=0.37), a pattern similar to the broader population. Among those not treated for GD (n=6), 1 of 2 responders had LGE and 1 of 4 non-responders had LGE (p=0.5). Conclusion CMR identified inflammation as a potential cause of GD in approximately 50% of HTx patients. There are 2 distinct patterns of LGE observed in GD, diffuse epicardial (56%) and patchy (44%). Although the presence of LGE in itself is not associated with myocardial recovery, 90% of patients with a diffuse epicardial pattern have recovery of GD. Funding Acknowledgement Type of funding source: None

Abstract. Peripheral arterial disease (PAD) management is exceptionally challenging. Despite advances in diagnostic and therapeutic technologies, long-term vessel patency and limb salvage rates are limited. Patients with PAD frequently require extensive workup with noninvasive tests and imaging to delineate their disease and help guide appropriate management. Ultrasound and computed tomography are commonly ordered in the workup of PAD. Magnetic resonance imaging (MRI), on the other hand, is less often acknowledged as a useful tool in this disease. Nevertheless, MRI is an important test that can effectively characterize atherosclerotic plaque, assess vessel patency in highly calcified disease, and measure lower extremity perfusion.

PurposeDixon‐based fat suppression has recently gained interest for dynamic contrast‐enhanced MRI, but multi‐echo techniques require longer scan times and reduce temporal resolution compared to single‐echo alternatives without fat suppression. The purpose of this work is to demonstrate accelerated single‐echo Dixon imaging with high spatial and temporal resolution.Theory and MethodsReal‐valued water and fat images can be obtained from a single measurement if the shared initial phase and that due to are assumed known a priori. An expression for simultaneous sensitivity encoding (SENSE) unfolding and fat‐water separation is derived for the general undersampling case, and simplified under the special case of uniform Cartesian undersampling. In vivo experiments were performed in extremities and brain with SENSE acceleration factors of up to R = 8.ResultsSingle‐echo Dixon reconstruction of highly undersampled data was successfully demonstrated. Dynamic contrast‐enhanced water and fat images provided high spatial and temporal resolution dynamic images with image update times shorter than previous single‐echo Dixon work.ConclusionTime‐resolved contrast‐enhanced MRI with single‐echo Dixon fat suppression shows high image quality, improved vessel delineation, and reduced sensitivity to motion when compared to time‐subtraction methods.

PurposeTo implement a reduced field of view (rFOV) technique for cardiac MR elastography (MRE) and to demonstrate the improvement in image quality of both magnitude images and post‐processed MRE stiffness maps compared to the conventional full field of view (full‐FOV) acquisition.MethodsWith Institutional Review Board approval, 17 healthy volunteers underwent both full‐FOV and rFOV cardiac MRE scans using 140‐Hz vibrations. Two cardiac radiologists blindly compared the magnitude images and stiffness maps and graded the images based on several image quality attributes using a 5‐point ordinal scale. Fisher's combined probability test was performed to assess the overall evaluation. The octahedral shear strain‐based signal‐to‐noise ratio (OSS‐SNR) and median stiffness over the left ventricular myocardium were also compared.ResultsOne volunteer was excluded because of an inconsistent imaging resolution during the exam. In the remaining 16 volunteers (9 males, 7 females), the rFOV scans outperformed the full‐FOV scans in terms of subjective image quality and ghosting artifacts in the magnitude images and stiffness maps, as well as the overall preference. The quantitative measurements showed that rFOV had significantly higher OSS‐SNR (median: 1.4 [95% confidence interval (CI): 1.2–1.5] vs. 2.1 [95% CI: 1.8–2.4]), P < 0.05) compared to full‐FOV. Although no significant change was found in the median myocardial stiffness between the 2 scans, we observed a decrease in the stiffness variation within the myocardium from 2.1 kPa (95% CI: [1.9, 2.3]) to 1.9 kPa (95% CI: [1.7, 2.0]) for full‐FOV and rFOV, respectively (P < 0.05) in a subgroup of 7 subjects with ghosting present in the myocardium.ConclusionThis pilot volunteer study demonstrated that rFOV cardiac MRE has the capability to reduce ghosting and to improve image quality in both MRE magnitude images and stiffness maps. Magn Reson Med 80:231–238, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Background: There is limited understanding of the role of cardiac computed tomography angiography (CCTA) for assessment of patients with spontaneous coronary artery dissection (SCAD). Methods: In this report we describe the diagnostic utility of CCTA in three young women presenting with signs and symptoms of myocardial ischemia who were eventually diagnosed with SCAD. Results: None of the women had traditional atherosclerotic risk factors. SCAD was not initially identified on CCTA in any of the three women, but was visualized during retrospective analysis in two patients after invasive coronary angiography. In two patients follow-up CCTA imaging was used successfully for subsequent management. Conclusions: In patients presenting with signs or symptoms of acute coronary syndrome, SCAD may be missed or not detectable on CCTA. A negative CCTA should not exclude a diagnosis of SCAD, and invasive coronary angiography should be considered for further evaluation.

Background Atrial fibrillation (AF) is the most common sustained atrial arrhythmia. One potential target for ablation is left atrial (LA) scar (LAS) regions that may be the substrate for re-entry within the atria, thereby sustaining AF. Identification of LAS through LA delayed gadolinium enhancement (LADE) with MRI has been proposed. Objectives We sought to evaluate LADE in patients referred for catheter ablation of AF. Methods Prospective analysis was conducted of consecutive patients who underwent pulmonary vein antrum isolation (PVAI) ablation for AF at a single institution. Patients underwent LADE with MRI to determine LAS regions before ablation. MRI data were analysed independently in accordance with prespecified institutional protocol by two staff cardiac radiologists to whom patient outcomes were masked, and reports of LADE were documented. Where no initial consensus occurred regarding delayed enhancement (DE), a third staff cardiac radiologist independently reviewed the case and had the deciding vote. Results Of the 149 consecutive patients (mean (SD) age, 59 (9) years), AF was persistent in 64 (43%) and paroxysmal in 85 (57%); 45 (30%) had prior ablation. Only five patients (3%) had identifiable DE in LA walls (persistent AF, n=1; paroxysmal AF, n=4). LADE was present in two (4%) of the 45 patients with previous left PVAI. The presence of LADE was not associated with a higher recurrence rate of AF. Conclusions In contrast to previous studies, the finding of DE within LA walls was uncommon and, when present, did not correlate with AF type or risk of AF recurrence. It therefore is of unclear clinical significance.

Objectives: Sarcopenia is associated with a poor prognosis in the ICU. The purpose of this study was to describe a simple sarcopenia index using routinely available renal biomarkers and evaluate its association with muscle mass and patient outcomes. Design: A retrospective cohort study. Setting: A tertiary-care medical center. Patients: High-risk adult ICU patients from October 2008 to December 2010. Interventions: The gold standard for muscle mass was quantified with the paraspinal muscle surface area at the L4 vertebrae in the subset of individuals with an abdominal CT scan. Using Pearson’s correlation coefficient, serum creatinine-to-serum cystatin C ratio was found to be the best performer in the estimation of muscle mass. The relationship between sarcopenia index and hospital and 90-day mortality, and the length of mechanical ventilation was evaluated. Measurements and Main Results: Out of 226 enrolled patients, 123 (54%) were female, and 198 (87%) were white. Median (interquartile range) age, body mass index, and body surface area were 68 (57–77) years, 28 (24–34) kg/m2, and 1.9 (1.7–2.2) m2, respectively. The mean (± sd) Acute Physiology and Chronic Health Evaluation III was 70 (± 22). ICU, hospital, and 90-day mortality rates were 5%, 12%, and 20%, respectively. The correlation (r) between sarcopenia index and muscle mass was 0.62 and coefficient of determination (r 2) was 0.27 (p < 0.0001). After adjustment for Acute Physiology and Chronic Health Evaluation III, body surface area, and age, sarcopenia index was independently predictive of both hospital (p = 0.001) and 90-day mortality (p < 0.0001). Among the 131 patients on mechanical ventilator, the duration of mechanical ventilation was significantly lower on those with higher sarcopenia index (–1 d for each 10 unit of sarcopenia index [95% CI, –1.4 to –0.2; p = 0.006]). Conclusions: The sarcopenia index is a fair measure for muscle mass estimation among ICU patients and can modestly predict hospital and 90-day mortality among patients who do not have acute kidney injury at the time of measurement.