Contrast-enhanced myocardial T1-weighted scout (Look-Locker) imaging for the detection of myocardial damages in hypertrophic cardiomyopathy.
ABSTRACT To assess the myocardial damage in hypertrophic cardiomyopathy (HCM) using contrast-enhanced myocardial T1-weighted scout (Look-Locker) magnetic resonance imaging (MRI).
Twenty-three patients with HCM and seven comparative patients without known HCM serving as controls underwent cine, contrast-enhanced myocardial T1-weighted scout and delayed-enhancement MRI using a 1.5T unit. Intervals of null points between myocardium and blood were compared among hyperenhancing and nullified myocardium of HCM and the normal myocardium. The relationship between these myocardial patterns and global cardiac functions was analyzed in HCM.
The hyperenhancing myocardium, dense myocardial fibrosis in HCM had null points significantly shorter than blood, normal myocardium, and nullified myocardium of HCM (P < 0.0001). The number of hyperenhancing myocardial segments correlated with the ejection fraction (P = 0.045). The nullified myocardium of HCM showed shorter intervals of the null points between myocardium and blood than did the normal myocardium, indicating the dispersed myocardial fibrosis (P = 0.0032). The interval of null points between the nullified myocardium and blood showed a significant correlation with the increase in myocardial mass in HCM (P = 0.034).
Contrast-enhanced myocardial T1-weighted scout imaging has the potential for showing dispersed myocardial damage leading to increased myocardial mass in HCM, while the dense myocardial fibrosis correlated with reduced ejection fraction.
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ABSTRACT: Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the heart. HCM is characterized by a wide range of clinical expression, ranging from asymptomatic mutation carriers to sudden cardiac death as the first manifestation of the disease. Over 1000 mutations have been identified, classically in genes encoding sarcomeric proteins. Noninvasive imaging is central to the diagnosis of HCM and cardiovascular magnetic resonance (CMR) is increasingly used to characterize morphologic, functional and tissue abnormalities associated with HCM. The purpose of this review is to provide an overview of the clinical, pathological and imaging features relevant to understanding the diagnosis of HCM. The early and overt phenotypic expression of disease that may be identified by CMR is reviewed. Diastolic dysfunction may be an early marker of the disease, present in mutation carriers prior to the development of left ventricular hypertrophy (LVH). Late gadolinium enhancement by CMR is present in approximately 60% of HCM patients with LVH and may provide novel information regarding risk stratification in HCM. It is likely that integrating genetic advances with enhanced phenotypic characterization of HCM with novel CMR techniques will importantly improve our understanding of this complex disease.Journal of Cardiovascular Magnetic Resonance 02/2012; 14:17. · 3.72 Impact Factor
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ABSTRACT: To evaluate the relationship between "Look-Locker" (LL) and modified Look-Locker Inversion recovery (MOLLI) approaches for T1 mapping of the myocardium. A total of 168 myocardial T1 maps using MOLLI and 165 maps using LL were obtained in human subjects at 1.5 Tesla. The T1 values of the myocardium were calculated before and at five time points after gadolinium administration. All time and heart rate normalizations were done. The T1 values obtained were compared to determine the absolute and bias agreement. The precontrast global T1 values were similar when measured by the LL and by MOLLI technique (mean, 1004.9 ms ± 120.3 versus 1034.1 ms ± 53.1, respectively, P = 0.26). Postcontrast myocardial T1 time from LL was significantly longer than MOLLI from 5 to 25 min (mean difference, LL - MOLLI was +61.8 ± 46.4 ms, P < 0.001). No significant differences in T1 values were noted between long and short axis measurements for either MOLLI or LL. Postcontrast LL and MOLLI showed very good agreement, although LL values are higher than MOLLI. Precontrast T1 values showed good agreement, however LL has greater limits of agreement. Short and long axis planes can reliably assess T1 values.Journal of Magnetic Resonance Imaging 09/2011; 34(6):1367-73. · 2.70 Impact Factor