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Elevated urinary albumin to creatinine ratio (ACR) and white matter hyperintensity (WMH) volume seen on brain MRI are measures of microvascular disease which may have shared susceptibility to metabolic and vascular insults. We hypothesized that elevated ACR may be useful as inexpensive biomarker to predict presence of cerebral microvascular disease. We assessed the association between ACR at study entry and subsequent WMH volume. We evaluated pulse pressure, mean arterial pressure, hypertension duration, waist circumference, fasting glucose, glomerular filtration rate (GFR) and C-reactive protein (CRP) as potential mediators and diabetes as a moderator of the association between ACR and WMH. Data were collected at study entry and at follow-up approximately 7 years later in a multiethnic population sample of 1281 participants (mean age=51, SD=9.5) from Dallas County. Overall, ACR differences were only marginally (p= 0.05) associated with subsequent WMH. In mediator analysis, however, ACR differences related specifically to arterial pulsatility(=0.010, bootstrap 95% Confidence Interval (CI): 0.002 to 0.021) and waist circumference (= -0.004, bootstrap 95% CI: -0.011 to -0.001) were significantly associated with WMH. ACR differences related to serum glucose and CRP were not associated with WMH. ACR evaluated at the same time as WMH had a higher level of significance (p< 0.001) indicating greater utility in predicting current cerebrovascular insults.

Introduction:Cardiomyopathy is a common complication in muscular dystrophy (MD) patients, though the mechanism is not clear. Retrospective data from adults with Duchenne muscular dystrophy suggest they have reduced LV mass compared to adults with other forms of non-ischemic cardiomyopathy. This raises the question whether pathologic hypertrophy contributes to the development of neuromuscular-associated cardiomyopathies. In this study, we hypothesized that MD patients have lower LV mass and associated changes in cardiac function as compared to healthy individuals.Methods:Utilizing cardiac magnetic resonance imaging (cMRI) data, a retrospective study was undertaken to compare LV mass, structure, and function between adults with MD and healthy age-, sex-, weight-matched controls from the Dallas Heart Study (DHS). Types of MD included dystrophinopathies, facioscapulohumeral MD, Freidreich ataxia, limb-girdle MD, myotonic dystrophy, and other rare MD. Approximately 50% of the MD patients were able to ambulate. MD patients were stratified into normal and reduced LVEF, defined as < 62% on cMRI, for further comparison. Statistical analysis was done using a two-sample, two-tailed t-test.Results:There were 339 MD patients (221 male) of mean age 40 and 417 DHS patients (187 male) of mean age 42. MD patients had a significantly lower LV mass, LV mass index, and LVEF than DHS adults. They also had significantly higher absolute and indexed volumes. In those with normal LVEF, all variables except LVESVi were significantly different from DHS. In those with reduced LVEF, all variables were significantly different from DHS. The results are summarized in Table 1.Conclusions:Collectively, MD patients have a reduced LV mass compared to healthy adults. In addition, MD patients with normal LVEF have lower LV mass than those patients with reduced LV function. Whether this observed decrease in LV mass represents cardiac hypoplasia or atrophy warrants further investigation.

Introduction:Duchenne muscular dystrophy (DMD) is a rare X-linked neuromuscular disorder affecting 1:5,000 males that results in terminal injury to the skeletal muscle and the heart. Recent evidence suggests that DMD female carriers are also at increased risk of developing cardiomyopathy. Renin-angiotensin-aldosterone system (RAAS) antagonists reduce morbidity and mortality and inhibit adverse left ventricular remodeling in patients with heart failure with reduced ejection fraction. The benefit of RAAS inhibition in DMD carriers has not been studied to date.Hypothesis:We hypothesize that RAAS inhibition will improve left ventricular function and induce favorable left ventricular structural changes in DMD carriers over time.Methods:A retrospective, single-center cohort study was undertaken to compare cardiac magnetic resonance imaging (cMRI) parameters in DMD carriers at the time of RAAS inhibitor initiation and after treatment with RAAS inhibitors for at least 12 months. RAAS inhibitors included angiotensin converting enzyme inhibitors, angiotensin receptor blockers, or angiotensin receptor neprilysin inhibitors. Through EMR review, demographic data and cMRI parameters were collected retrospectively on 20 consecutive DMD carriers.Results:The average time elapsed between cMRIs was 39 months. Overall, left ventricular ejection fraction (LVEF) increased in DMD carriers over time, though the improvement in LVEF did not reach significance (57%+8 vs 59%+6, p=0.2). However, subgroup analysis of 16 DMD carriers with reduced LVEF (defined as LVEF <62%) demonstrated significant improvement in LVEF following RAAS inhibition (54%+6 vs 58%+7; p= 0.004). DMD carriers with reduced LVEF additionally demonstrated a significant decrease in left ventricular end systolic volume index (LVESVi) after RAAS inhibition (38+10 vs 32+10 ml/m2; p= 0.013).Conclusions:DMD carriers with reduced LVEF showed significant improvement in LVEF and LVESVi following RAAS inhibition. Collectively, the data suggest that RAAS inhibition significantly improves left ventricular systolic function and significantly reduces maladaptive left ventricular remodeling and dilation in this population.

Detection and evaluation of aortic root and other cardiovascular abnormalities in patients with Marfan's syndrome are important in determining appropriate therapy and preventing premature mortality. To evaluate the role of nuclear magnetic resonance imaging (NMR) in this syndrome, 10 patients were evaluated using a 0.35 tesla commercial nuclear magnetic resonance imaging system. Findings from these studies were compared with data from other noninvasive tests as well as surgical follow-up. Results from these examinations indicate that NMR-derived measurements of aortic root diameter agree closely with echocardiography measurements. In addition, NMR provides more complete anatomic detail than does echocardiography and can be utilized to assess and follow up virtually all patients with this syndrome.

Previous nuclear magnetic resonance (NMR) imaging studies have indicated that coronary occlusion does not produce sufficient changes in standard tissue relaxation times to allow the detection of acute ischemia. To identify acute myocardial perfusion abnormalities, the use of the paramagnetic agent manganese gluconate combined with calcium gluconate (MnGlu/CaGlu) was investigated in canine models of acute coronary artery occlusion.

A quantitative nuclear magnetic resonance (NMR) imaging method of evaluating regional left ventricular function was compared with histochemical evidence of infarction in dogs and functional measurements in patients. Short-axis images of the heart were obtained at end-diastole and at 100 ms intervals thereafter. Regional diastolic left ventricular wall thickness and maximal percent systolic wall thickening were measured at the level of the papillary muscles in each of six segments. In six normal dogs, the mean end-diastolic wall thickness was 9 ± 1.6 mm, and the mean maximal percent thickening was 61 ± 11%. In eight dogs with a 4 day old infarct, maximal percent thickening was 5 ± 8% (p < 0.001) in the infarcted segments.

To examine the accuracy of nuclear magnetic resonance imaging in measuring left ventricular mass, measurements of left ventricular mass made using this technique were compared with left ventricular weight in 10 mongrel dogs. Left ventricular myocardial volume was measured from five short-axis ehd-diastolic images that spanned the left ventricle. Left ventricular mass was calculated from left ventricular myocardial volume and compared with the left ventricular weight determined after formalin immersion-fixation.

OBJECTIVE: Transcorneal oxygenation is a promising approach to the treatment of various anterior ocular diseases, but its effect on the vitreous and retina is uncertain. The purpose of this study was to evaluate the ocular conditions necessary to permit transcorneal oxygenation of the preretinal vitreous in the rabbit eye. METHODS: Oxygen at atmospheric pressure was supplied via a goggle to the eye while preretinal oxygen tensions were measured with a minimally invasive technique: fluorine-19 (19F) nuclear magnetic resonance spectroscopy of a small preretinal droplet of perfluorotributylamine. Experiments were performed on lensectomized eyes with intact posterior lens capsules (group 1) or in eyes that had also undergone posterior capsular discission (group 2) and mechanical vitrectomy (group 3). To better understand the results of the oxygenation studies, a water-soluble, freely diffusible contrast agent was applied topically to the cornea, and its penetration into the aqueous and vitreous was studied using T1-weighted magnetic resonance imaging. RESULTS: Preretinal Po2 was significantly increased after 30 minutes of transcorneal oxygenation in group 3 eyes (P=.002). In contrast, no change was observed in the other groups despite 30 minutes (group 1) or 3 hours (group 2) of oxygen exposure. The imaging studies demonstrated that contrast penetration of the vitreous was uniform and rapid in eyes in group 3, consistent with a fluid flow-dominated process. A much slower process of anterior and midvitreous enhancement was observed in groups 1 and 2 that was consistent with contrast diffusion. CONCLUSIONS: Because of bulk fluid movement, transcorneal oxygenation of the retina is feasible in singlecompartment (vitrectomized, lensectomized) eyes within a reasonable period (30 minutes). This finding could prove useful in the treatment of retinal diseases in which hypoxia may play a role.

Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA)-enhanced nuclear magnetic resonance (NMR) imaging can be useful in the identification of reperfused myocardium. However, the effects of dose and the time of administration and the relation of the extent of the region of enhancement to the myocardial bed at risk have not been evaluated. In this study, dogs were given Gd-DTPA (0.1 mM/kg body weight [n = 21] or 0.34 mM/kg [n = 7]) or saline solution (n = 5) after various periods of occlusion and reperfusion. Twenty-five dogs were killed after 1 or 2 h of reperfusion and the excised hearts were imaged. Images were analyzed for presence, intensity and extent of a region of increased signal.