Jennifer A. Dickerson

Cardiac Magnetic Resonance With Edema Imaging Identifies Myocardium at Risk and Predicts Worse Outcome in Patients With Non-ST-Segment Elevation Acute Coronary Syndrome

OBJECTIVES The aim of this study was to define the prevalence and significance of myocardial edema in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS). BACKGROUND Most patients with NSTE-ACS undergo angiography, yet not all have obstructive coronary artery disease (CAD) requiring revascularization. Identifying patients with myocardium at risk could enhance the effectiveness of an early invasive strategy. Cardiac magnetic resonance (CMR) can demonstrate edematous myocardium subjected to ischemia but has not been used to evaluate NSTE-ACS patients. METHODS One hundred consecutive patients with NSTE-ACS were prospectively enrolled to undergo 30-min CMR, including T2-weighted edema imaging and late gadolinium enhancement before coronary angiography. Clinical management including revascularization decision-making was performed without CMR results. RESULTS Of 88 adequate CMR studies, 57 (64.8%) showed myocardial edema. Obstructive CAD requiring revascularization was present in 87.7% of edema-positive patients versus 25.8% of edema-negative patients (p < 0.001). By multiple logistic regression analysis after adjusting for late gadolinium enhancement, perfusion, and wall motion scores, TIMI risk score was not predictive of obstructive CAD. Conversely, an increase in T2 score by 1 U increased the odds of subsequent coronary revascularization by 5.70 times (95% confidence interval: 2.38 to 13.62, p < 0.001). Adjusting for peak troponin-I, patients with edema showed a higher hazard of a cardiovascular event or death within 6 months after NSTE-ACS compared with those without edema (hazard ratio: 4.47, 95% confidence interval: 1.00 to 20.03; p = 0.050). CONCLUSIONS In NSTE-ACS patients, rapid CMR identifies reversibly injured myocardium due to obstructive CAD and predicts worse outcomes. Identifying myocardium at risk may help direct appropriate patients toward early invasive management.

Real-time cine and myocardial perfusion with treadmill exercise stress cardiovascular magnetic resonance in patients referred for stress SPECT

BackgroundTo date, stress cardiovascular magnetic resonance (CMR) has relied on pharmacologic agents, and therefore lacked the physiologic information available only with exercise stress.Methods43 patients age 25 to 81 years underwent a treadmill stress test incorporating both Tc99m SPECT and CMR. After rest Tc99m SPECT imaging, patients underwent resting cine CMR. Patients then underwent in-room exercise stress using a partially modified treadmill. 12-lead ECG monitoring was performed throughout. At peak stress, Tc99m was injected and patients rapidly returned to their prior position in the magnet for post-exercise cine and perfusion imaging. The patient table was pulled out of the magnet for recovery monitoring. The patient was sent back into the magnet for recovery cine and resting perfusion followed by delayed post-gadolinium imaging. Post-CMR, patients went to the adjacent SPECT lab to complete stress nuclear imaging. Each modalitys images were reviewed blinded to the others results.ResultsPatients completed on average 9.3 ± 2.4 min of the Bruce protocol. Stress cine CMR was completed in 68 ± 14 sec following termination of exercise, and stress perfusion CMR was completed in 88 ± 8 sec. Agreement between SPECT and CMR was moderate (κ = 0.58). Accuracy in eight patients who underwent coronary angiography was 7/8 for CMR and 5/8 for SPECT (p = 0.625). Follow-up at 6 months indicated freedom from cardiovascular events in 29/29 CMR-negative and 33/34 SPECT-negative patients.ConclusionsExercise stress CMR including wall motion and perfusion is feasible in patients with suspected ischemic heart disease. Larger clinical trials are warranted based on the promising results of this pilot study to allow comparative effectiveness studies of this stress imaging system vs. other stress imaging modalities.

Gender-Related Differences in Coronary Artery Dimensions: A Volumetric Analysis

Women consistently have poorer revascularization outcomes and more coronary vascular complications compared to men. This has been attributed to smaller coronary arteries, though limited data exist to support this assumption.

MR-compatible treadmill for exercise stress cardiac magnetic resonance imaging.

This article describes an MR‐safe treadmill that enables cardiovascular exercise stress testing adjacent to the MRI system, facilitating cardiac MR imaging immediately following exercise stress. The treadmill was constructed of nonferromagnetic components utilizing a hydraulic power system. Computer control ensured precise execution of the standard Bruce treadmill protocol commonly used for cardiovascular exercise stress testing. The treadmill demonstrated no evidence of ferromagnetic attraction and did not affect image quality. Treadmill performance met design specifications both inside and outside the MRI environment. Ten healthy volunteers performed the Bruce protocol with the treadmill positioned adjacent to the MRI table. Upon reaching peak stress (98 ± 8% of age‐predicted maximum heart rate), the subjects lay down directly on the MRI table, a cardiac array coil was placed, an intravenous line connected, and stress cine and perfusion imaging performed. Cine imaging commenced on average within 24 ± 4 s and was completed within 40 ± 7 s of the end of exercise. Subject heart rates were 86 ± 9% of age‐predicted maximum heart rate at the start of imaging and 81 ± 9% of age‐predicted maximum heart rate upon completion of cine imaging. The MRI‐compatible treadmill was shown to operate safely and effectively in the MRI environment. Magn Reson Med, 2012.

Diagnostic Performance of Treadmill Exercise Cardiac Magnetic Resonance: The Prospective, Multicenter Exercise CMR's Accuracy for Cardiovascular Stress Testing (EXACT) Trial

Background Stress cardiac magnetic resonance (CMR) has typically involved pharmacologic agents. Treadmill CMR has shown utility in single‐center studies but has not undergone multicenter evaluation. Methods and Results Patients referred for treadmill stress nuclear imaging (SPECT) were prospectively enrolled across 4 centers. After rest 99mTc SPECT, patients underwent resting cine CMR. In‐room stress was then performed using an MR‐compatible treadmill with continuous 12‐lead electrocardiogram monitoring. At peak stress, 99mTc was injected, and patients rapidly returned to the MR scanner isocenter for real‐time, free‐breathing stress cine and perfusion imaging. After recovery, cine and rest perfusion followed by late gadolinium enhancement acquisitions concluded CMR imaging. Stress SPECT was then acquired in adjacent nuclear laboratories. A subset of patients not referred for invasive coronary angiography within 2 weeks of stress underwent coronary computed tomography angiography. Angiographic data available in 94 patients showed sensitivity of 79%, specificity of 99% for exercise CMR with positive predictive value of 92% and negative predictive value of 96%. Agreement between treadmill stress CMR and angiography was strong (κ=0.82), and moderate between SPECT and angiography (κ=0.46) and CMR versus SPECT (κ=0.48). Conclusions The multicenter EXACT trial indicates excellent diagnostic value of treadmill stress CMR in typical patients referred for exercise SPECT.

Comparison of treadmill exercise stress cardiac MRI to stress echocardiography in healthy volunteers for adequacy of left ventricular endocardial wall visualization: A pilot study.

To compare exercise stress cardiac magnetic resonance (cardiac MR) to echocardiography in healthy volunteers with respect to adequacy of endocardial visualization and confidence of stress study interpretation.

Collaborating with cardiac sonographers to develop work-related musculoskeletal disorder interventions

Abstract For more than two decades, surveys of imaging technologists, including cardiac sonographers, diagnostic medical sonographers and vascular technologists, have consistently reported high prevalence of work-related musculoskeletal discomfort (WRMSD). Yet, intervention research involving sonographers is limited. In this study, we used a participatory approach to identifying needs and opportunities for developing interventions to reduce sonographers’ exposures to WRMSD risk factors. In this paper, we present some of those needs. We include descriptions of two interventions, targeted for cardiac sonographers, that were developed, through an iterative process, into functional prototypes that were evaluated in pilot tests by practicing sonographers. One of these interventions is now in daily use. We would like other engineers and ergonomists to recognise this area of opportunity to apply their knowledge of biomechanics and design in order to begin to address the high prevalence of WRMSDs in sonographers, by working with sonographers to develop useful and usable interventions. Practitioner Summary: This paper discusses needs, opportunities and methods for working with sonographers in order to develop interventions to reduce their exposure to risk factors for work-related musculoskeletal discomfort. Results from field tests of two novel interventions targeting cardiac sonographers are also presented.

Relationship of Cardiac Magnetic Resonance Imaging and Myocardial Biopsy in the Evaluation of Nonischemic Cardiomyopathy

This study was performed to determine the relative role of cardiac magnetic resonance (CMR) imaging and endomyocardial biopsy (EMB) in the evaluation of cardiomyopathy. Sixty-six patients with a clinical diagnosis of nonischemic dilated cardiomyopathy or restrictive cardiomyopathy underwent both EMB and CMR imaging as part of their diagnostic evaluation. The authors retrospectively reviewed the results of these two methods to determine their diagnostic impact and congruency. CMR imaging provided data on cardiac anatomy, left ventricular volumes, mass, and function in 85% of the patients, uncovered fibrosis in 31%, myocardial ischemia in 7%, and fibrofatty infiltration in two patients. EMB provided the histologic findings of cardiomyocyte hypertrophy in 77% of patients and substantial interstitial fibrosis in 59%. Six patients had EMB-proven amyloid heart disease, which was detected by CMR imaging in two. CMR imaging showed patterns of late gadolinium enhancement supportive of infiltrative disease or inflammation in 6 patients with EMB-proven definite (n=3) or borderline (n=3) myocarditis, but failed to do so in two other patients with borderline and two with resolving myocarditis. At the present time, CMR imaging and EMB remain complementary procedures in the evaluation of cardiomyopathic conditions.

Myocardial ischemia in the absence of epicardial coronary artery disease in Friedreich's ataxia

We present the first in vivo detection of microvascular abnormality in a patient with Friedreichs ataxia (FA) without epicardial coronary artery disease using cardiac magnetic resonance (CMR). The patient had exertional chest pain and dyspnea prompting referral for cardiac evaluation. These symptoms were reproduced during intravenous adenosine infusion, and simultaneous first-pass perfusion imaging showed a significant subendocardial defect; both symptoms and perfusion deficit were absent at rest. Epicardial coronaries were free of disease by invasive angiography; together, these findings support the notion of impaired myocardial perfusion reserve in FA.

Isolated cardiac metastasis from plasmacytoid urothelial carcinoma of the bladder

A 57-year-old male with a history of hypertension presented with shortness of breath, intermittent substernal chest pain, subjective fevers, and a 30-pound weight loss. He was found to have a bladder mass four months prior to presentation, for which he underwent cystoscopy and surgical removal. Pathology demonstrated high-grade superficial plasmacytoid urothelial carcinoma extending into the submucosa but not the muscularis propria. Given the superficial nature of his bladder cancer, a cystectomy was deferred. He was subsequently lost to follow-up care. On arrival, physical exam was notable for tachycardia, tachypnea, and distant heart sounds. An ECG showed an incomplete right bundle branch block and sinus tachycardia. Computed tomography pulmonary angiography revealed a three-cm pericardial effusion. Transthoracic echocardiography confirmed this finding and revealed a mass in the right ventricle (RV) extending into the outflow tract and infiltrating the free wall. The RV was dilated with an estimated RV systolic pressure of 37 mmHg. Pericardiocentesis yielded nearly one liter of serosanguinous fluid with non-diagnostic cytology. Partial median sternotomy with biopsy showed pathologic findings consistent with metastatic urothelial carcinoma, plasmacytoid variant. A PET scan showed increased uptake exclusively in the heart. The oncology team discussed options with the patient including chemotherapy and palliative care. The patient decided to withhold further therapy and went home with hospice care. He died two months later.DiscussionBladder cancer is the fourth most common cancer in men in the United States. Most patients (69%) with metastatic bladder cancer have multiple organs involved; conversely, our patient had a PET scan indicating his disease was localized to the heart. Plasmacytoid urothelial carcinoma is a rare subtype of bladder cancer, and is estimated to make up less than three percent of all invasive bladder carcinomas. At the time of this publication we are aware of only three other reported instances of isolated cardiac metastasis with urothelial bladder origin; none of which were the plasmacytoid variant.ConclusionThis case highlights a previously unreported presentation of plasmacytoid urothelial carcinoma. Clinicians must remember that even superficial cancers can have significant metastatic potential.