Purpose:To investigate the potential value and relationship of in vivo quantification of apparent diffusion coefficients (ADCs) and T2 relaxation times for characterizing brain tumor cellularity and tumor-related edema. Materials and Methods:A total of 26 patients with newly diagnosed gliomas, meningiomas, or metastases underwent diffusion-weighted and six-echo multisection T2-preparation imaging. Regions of interest (ROIs) were drawn on conventional MR images to include tumor (as defined by contrast agent enhancement) and immediate and peripheral edema. Areas of necrosis were excluded. Median values of ADCs and T2 in the ROIs were calculated.Results: ADCs for gliomas were similar to those for meningiomas or metastases in all regions. Tumor T2 values for gliomas (159.5 Ϯ 30.6 msec) were significantly higher than those for meningiomas or metastases (125.0 Ϯ 31.1 msec; P ϭ 0.005). Immediate-edema T2 values for meningiomas or metastases (226.0 Ϯ 44.1 msec) were significantly higher than those for gliomas (203.5 Ϯ 32.8 msec; P ϭ 0.033). Peripheral-edema T2 values for gliomas (219.5 Ϯ 41.9 msec) were similar to those for meningiomas or metastases (202.5 Ϯ 26.5 msec; P ϭ 0.377). Both immediate-and peritumoral-edema ADCs and T2 values were significantly higher than those in tumor for both tumor types. ADCs and T2 values from all regions correlated significantly for gliomas (r ϭ 0.95; P Ͻ 0.0001) and for meningiomas or metastases (r ϭ 0.81; P Ͻ 0.0001). Conclusion:The higher immediate-edema T2 values for nonglial tumors than for gliomas suggest tumor-related edema (vasogenic vs. infiltrated) can be further characterized by using T2 values. There were significant correlations between ADC and T2 values.

Background-More than 50% of >270 000 childhood cancer survivors in the United States have been treated with anthracyclines and are therefore at risk of developing cardiotoxicity. Cardiac magnetic resonance (CMR) has demonstrated utility to detect diffuse interstitial fibrosis and changes in regional myocardial function. We hypothesized that CMR would identify occult cardiotoxicity characterized by structural and functional myocardial abnormalities in a cohort of asymptomatic pediatric cancer survivors with normal global systolic function. Methods and Results-Forty-six long-term childhood cancer survivors with a cumulative anthracycline dose ≥200 mg/m 2 and normal systolic function were studied 2.5 to 26.9 years after anthracycline exposure. Subjects underwent transthoracic echocardiography, CMR with routine cine acquisition, tissue characterization, and left ventricular strain analysis using a modified 16-segment model. Extracellular volume was measured in 27 subjects, all of whom were late gadolinium enhancement negative. End-systolic fiber stress was elevated in 45 of 46 subjects. Low average circumferential strain magnitude (ε cc ) −14.9±1.4; P<0.001, longitudinal strain magnitude (ε ll ) −13.5±1.9; P<0.001, and regional peak circumferential strain were seen in multiple myocardial segments, despite normal global systolic function by transthoracic echocardiography and CMR. The mean T1 values of the myocardium were significantly lower than that of control subjects at 20 minutes (458±69 versus 487±44 milliseconds; P=0.01). Higher mean extracellular volume was observed in female subjects (0.34 versus 0.22; P=0.01). The purpose of this study was to use CMR T1 mapping techniques and measures of myocardial strain by tagged cine MRI to detect interstitial disease and changes in regional myocardial function in childhood cancer survivors. We tested the hypothesis that individuals with a history of high-dose anthracycline therapy may have occult cardiotoxicity, manifested by a decrease in circumferential ε cc and longitudinal ε ll strain magnitude and changes in myocardial T1 and ECV, despite normal standard measures of global left ventricular (LV) systolic function. Conclusions-Asymptomatic Methods Study PopulationEligible subjects with a cumulative anthracycline dose ≥200 mg/m 2 and normal LV systolic function defined as TTE-based shortening fraction ≥29% were identified and prospectively enrolled through a registry of pediatric cancer survivors treated with anthracyclines between 1985 and January 2011. Inclusion criteria for this study are shown in Figure 1. Subjects with high-dose radiation exposure to the chest (>3000 cGy) were excluded from the study to minimize the known synergistic effect of therapeutic radiation on cardiotoxicity. 5,21This study was approved by the Institutional Review Board at the Connecticut Children's Medical Center. The medical records of all enrolled subjects were reviewed to identify known risk factors associated with cardiotoxicity. Conversions to isotoxic equivalents of anthracycline a...

Cardiac arrhythmias reflect abnormal electric activity in the heart. Radiofrequency ablation (RFA) is used to treat different arrhythmias by thermally damaging tissue regions and eliminating irregular action potential propagation paths. To ensure a permanent electric block, RFA must create a continuous line of transmural lesions.1 Notwithstanding extensive efforts, the success rates of the RFA operations are still low, 2 likely because of the lack of tools to validate the lesion extent. Current ablation methods rely on suboptimal fluoroscopy and electrophysiology electroanatomic systems; fluoroscopy has poor soft tissue contrast, and even with electroanatomic systems locating and characterizing the ablation lesions are challenging. More importantly, it is difficult to predict which of the lesions that yield a conduction block in the acute setting will maintain a block in the chronic setting. Clinical Perspective on p 727MRI is a powerful tool to detect ablation lesions because of its high soft tissue contrast. Double inversion fast spin echo (DIR) sequence demonstrates intrinsic T 2 -weighted contrast and quickly detect lesions, but DIR images lack specificity and provide poor border visibility. 3,4 Late gadolinium enhancement (LGE) methods provide high contrast between healthy myocardium and the ablation lesions. 3,[5][6][7] However, acute lesion appearance on the LGE image varies with the time between the Gd-DTPA injection and image acquisition because of the wash-in/wash-out kinetics, 7 particularly in areas associated with microvascular obstruction. Shortly after Gd-DTPA injection, the lesion contains hypoenhanced regions in typical LGE acquisitions. Then Gd-DTPA starts to enter the lesion, and a bright rim becomes visible. As the bright rim expands toward the center of the lesion over the ensuing minutes, wash-out mechanisms also begin to diminish the contrast at the outer border of the lesion. The lesion severity can also affect the wash-in/wash-out kinetics. As a second consideration, a recent study reported that the scar size measured 3 months after ablation with LGE images is <50% of that measured acutely. 6 One of the possible reasons for this © 2014 American Heart Association, Inc. Original ArticleBackground-Both intrinsic contrast (T 1 and T 2 relaxation and the equilibrium magnetization) and contrast agent (gadolinium)-enhanced MRI are used to visualize and evaluate acute radiofrequency ablation lesions. However, current methods are imprecise in delineating lesion extent shortly after the ablation. Methods and Results-Fifteen lesions were created in the endocardium of 13 pigs. A multicontrast inversion recovery steady state free precession imaging method was used to delineate the acute ablation lesions, exploiting T 1 -weighted contrast. T 2 and M o * maps were also created from fast spin echo data in a subset of pigs (n=5) to help characterize the change in intrinsic contrast in the lesions. Gross pathology was used as reference for the lesion size comparison, and the lesion structures were confirm...