ROBUST CONTRAST FOR AUTO--ANALYSIS OF CARDIAC MRI

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DESCRIPTION (Adapted from Applicant's Abstract): The applicants presented preliminary experiments showing Tlrho weighting and enhancement with Gd-DTPA injection combine to improve contrast of cine images of the heart greatly and to bring results of automated analysis closer to results of manual analysis. The applicants hypothesized this improved contrast could improve diagnostic accuracy and make automated analysis of cardiac function reliable enough to replace physician-intensive, manual analysis of multislice, multiphase images. Such replacement is important because manual analyses are not usually performed. When they are, generally only ejection fractions and systolic thickening are estimated. Routine cine images also determine rates of change, which may be more sensitive to disease, but analyzing images manually is so tedious that these data are usually wasted. The applicants proposed, starting from their present, Tlrho/Gd-DTPA method, to develop high-contrast, robust protocols using navigator echoes to control the effect of normal breathing during examination and, to provide greater coverage in less time, echo planar imaging. They proposed to compare diagnoses made from conventional and improved images and to compare automated analyses of conventional and improved images using an existing software package that automatically detects edges to draw endocardial and epicardial contours and to extract functional indices. They would determine which aspects of image quality are most important to automated analysis. With the developers of the software, they would modify and improve the analysis program to exploit improved image contrast fully. The image generation and optimization effort would require simulation of pulse sequences, then testing promising ones on patients. Patients with questionable ventricular function due to coronary artery disease, cardiomyopathy, or end-stage lung disease or who are candidates for heart or lung transplant would be examined, comparing diagnoses from conventional and improved images. To test automated analyses, automatic results would be compared to manual results on the same images and to automatic results on repeated scans. For reference, manual results would be compared to repeated manual analysis of the same data and of repeat scans. Comparisons would include endocardial areas and volumes in the left and right ventricles, ejection fractions, the peak rates of ejection and filling, and the times at which end systole, end diastole, and the peak flow rates occur.