Background-The relation between infarct tissue heterogeneity on contrast-enhanced MRI and the occurrence of spontaneous ventricular arrhythmia (or sudden cardiac death) is unknown. Therefore, the study purpose was to evaluate the predictive value of infarct tissue heterogeneity assessed with contrast-enhanced MRI on the occurrence of spontaneous ventricular arrhythmia with subsequent implantable cardioverter-defibrillator (ICD) therapy (as surrogate of sudden cardiac death) in patients with previous myocardial infarction.

Objectives This study sought to determine the relationship of cardiovascular magnetic resonance (CMR) measures of tissue composition to age in the Multi-Ethnic Study of Atherosclerosis (MESA). Background Animal and human studies have demonstrated increased collagen deposition in senescent hearts. New CMR indices of tissue composition by using T1 mapping are sensitive to the presence of myocardial fibrosis. Methods A total of 1,231 study participants (51% women; age range 54 to 93 years) of the MESA cohort were evaluated with T1 mapping by using 1.5-T CMR scanners. None of the participants had focal scar on delayed enhancement CMR. Single-slice T1 mapping was performed at the midventricular level before and at 12- and 25-min delay after administration of gadolinium contrast by using a modified Look-Locker inversion recovery sequence. The partition coefficient was determined by the slope of the linear relationship of (1/T1myo vs. 1/T1blood). The extracellular volume fraction (ECV) was derived accounting for the hematocrit level. Multivariable regression analyses were performed, adjusting for traditional risk factors and left ventricular structure. Results Women had significantly greater partition coefficient, ECV, and precontrast T1 than men, as well as lower post-contrast T1 values (all p < 0.05). In general, linear regression analyses demonstrated that greater partition coefficient, pre-contrast T1 values, and ECV were associated with older age in men (multivariate regression coefficients = 0.01; 5.9 ms; and 1.04% per 10 years’ change; all p < 0.05). ECV was also significantly associated with age in women after multivariable adjustments. Conclusions CMR parameters that have been associated with myocardial fibrosis were related to older age in the MESA study. Women had higher ECV than men but less ECV change over time.

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Purpose:To determine the utility of cardiac magnetic resonance (MR) T1 mapping for quantification of diffuse myocardial fibrosis compared with the standard of endomyocardial biopsy. Materials and Methods:This HIPAA-compliant study was approved by the institutional review board. Cardiomyopathy patients were retrospectively identified who had undergone endomyocardial biopsy and cardiac MR at one institution during a 5-year period. Forty-seven patients (53% male; mean age, 46.8 years) had undergone diagnostic cardiac MR and endomyocardial biopsy. Thirteen healthy volunteers (54% male; mean age, 38.1 years) underwent cardiac MR as a reference. Myocardial T1 mapping was performed 10.7 minutes 6 2.7 (standard deviation) after bolus injection of 0.2 mmol/kg gadolinium chelate by using an inversion-recovery Look-Locker sequence on a 1.5-T MR imager. Late gadolinium enhancement was assessed by using gradientecho inversion-recovery sequences. Cardiac MR results were the consensus of two radiologists who were blinded to histopathologic findings. Endomyocardial biopsy fibrosis was quantitatively measured by using automated image analysis software with digital images of specimens stained with Masson trichrome. Histopathologic findings were reported by two pathologists blinded to cardiac MR findings. Statistical analyses included Mann-Whitney U test, analysis of variance, and linear regression. Results:Median myocardial fibrosis was 8.5% (interquartile range, 5.7-14.4). T1 times were greater in control subjects than in patients without and in patients with evident late gadolinium enhancement (466 msec 6 14, 406 msec 6 59, and 303 msec 6 53, respectively; P , .001). T1 time and histologic fibrosis were inversely correlated (r = 20.57; 95% confidence interval: 20.74, 20.34; P , .0001). The area under the curve for myocardial T1 time to detect fibrosis of greater than 5% was 0.84 at a cutoff of 383 msec. Conclusion:Cardiac MR with T1 mapping can provide noninvasive evidence of diffuse myocardial fibrosis in patients referred for evaluation of cardiomyopathy.q RSNA, 2012

Purpose: To validate magnetic resonance imaging (MRI) assessment of aortic pulse wave velocity (PWV MRI ) with PWV determined from invasive intra-aortic pressure measurements (PWV INV ) and to test the reproducibility of the measurement by MRI. Materials and Methods:PWV MRI was compared with PWV INV in 18 nonconsecutive patients scheduled for catheterization for suspected coronary artery disease. Reproducibility of PWV MRI was tested in 10 healthy volunteers who underwent repeated measurement of PWV MRI at a single occasion. Velocity-encoded MRI was performed on all participants to assess PWV MRI in the total aorta (Ao total ), the proximal aorta (Ao prox ), and the distal aorta (Ao dist ). Conclusion: MRI assessment of aortic pulse wave velocity shows good agreement with invasive pressure measurements and can be determined with high reproducibility. Results

Purpose: To evaluate reproducibility of total cerebral blood flow (CBF) measurements with phase contrast magnetic resonance imaging (pcMRI). Materials and Methods:We repeated total CBF measurements in 15 healthy volunteers with and without cardiac triggering, and with and without repositioning. In eight volunteers measurements were performed at two different occasions. In addition, measurement of flow in a phantom was performed to validate MR measurements. Results:A difference of 40.4 ml/minute was found between CBF measurements performed with and without triggering (P Ͻ 0.05). For repeated triggered measurements, the coefficient of variation (CV) was 7.1%, and for nontriggered measurements 10.3%. For repeated measurements with repositioning, the CV was 7.1% with and 11.2% without triggering. Repeated measurements at different occasions showed a CV of 8.8%. Comparing measured with real flow in the phantom, the triggered differed 4.9% and the nontriggered 8.3%. Conclusion:The findings of this study demonstrate that pcMRI is a reliable method to measure total CBF in terms of both accuracy and reproducibility. METHODS THAT CURRENTLY ARE USED to assess total cerebral blood flow (CBF) can be divided into two groups based on the underlying concepts. On the one hand, total CBF can be estimated based on information generated by flow in the capillaries; on the other hand, total CBF can be assessed by measuring flow in the supplying vessels of the brain. Methods that are based on measurements of flow in the capillaries are single positron emission computed tomography (SPECT), xenon-computed tomography (Xe-CT), and perfusion magnetic resonance imaging (MRI). Blood flow in the supplying vessels of the brain can be measured using Doppler ultrasound and phase contrast MRI (pcMRI). Advantages of both Doppler ultrasound and pcMRI are no need for using ionizing irradiation or administration of intravenous agents, and the possibility of repeated measurements on a short-term basis. However, limitations of Doppler ultrasound are its operator dependency and overestimation of total blood flow in a given vessel due to the fact that only the highest flow in the center of the vessel is assessed (1). Using pcMRI, total CBF can be assessed by simultaneously measuring flow in the internal carotid arteries and the basilar artery. As compared to Doppler ultrasound, pcMRI has the advantage of being operator independent and involving straightforward flow quantification. In addition, pcMRI can be added to morphologic MRI sequences, offering the option to correlate flow to morphology based on data generated during one examination.In vitro and in vivo studies have demonstrated that pcMRI provides reliable flow data (2-4). However, data on short-term and long-term reproducibility are scarce. Furthermore, there is an ongoing discussion whether total CBF should be measured using a cardiac-triggered or a nontriggered pcMRI technique (4 -6). Finally, using pc-MRI, considerable differences in total CBF have been found between healthy volunteers (7,8). ...

PACAP38-induced headache is associated with prolonged dilatation of the MMA but not of the MCA. Sumatriptan relieves headache in parallel with contraction of the MMA but not of the MCA.

Flow assessment using 3D 3-directional VE MR with retrospective valve-tracking during off-line analysis enables accurate quantification of net flow volumes through 4 heart valves within a single acquisition in healthy volunteers and in patients with valvular regurgitation.