Fat- and Water-Selective MR Cine Imaging of the Human Heart

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Abstract
The purpose of this study was to develop and implement MR sequences for chemical shift–selective breath-hold cine imaging of the heart. Fibroadipose conversion of myocardium in cases suspected of right ventricular dysplasia should be revealed in fat- and water-selective MR images of high quality. Frequency-selective saturation of one chemical shift component was applied in modified k-space–segmented, electrocardiography-gated sequences, allowing high-quality cine imaging of the human heart in a single breath-hold. Phantom studies and human examinations in eight normal subjects (aged 24–62 years) and in seven patients (aged 31–47 years) with suspected right ventricular dysplasia were performed. The patients showed suspicious findings, such as a dyskinetic and dilated right ventricle combined with ventricular arrhythmia, and underwent MR imaging after exclusion of other possible reasons (eg, coronary artery disease or pulmonary hypertension). High selectivity to the desired chemical shift component was confirmed by test measurements in a phantom containing water and lipids. In the human subjects, minor problems with magnetic field inhomogeneities appeared in the thoracic walls only. Four patients with suspected right ventricular dysplasia showed clearly abnormal signal behavior of the right myocardial wall in both fat- and water-selective cine images. Bright transmural structures were exhibited in fat-selective images, but the origin of the fat (epicardium or infiltrated myocardium) was often difficult to assess. Right ventricular areas with fibrosis and fatty degeneration often show normal signal intensity in standard T1-weighted images but can be differentiated from normal tissue by the new chemical shift–selective breath-hold cine techniques.