Volume Curve

30000 -20000 i 10000 ~

0 ~ i—i—i—i—i—i T~ | i—i—i—i—i—r r | r i ,,r,,i",,7~ i 7~ 0 8 16 24

Figure 5. Left ventricular time-activity curve. Using the best septal view, regions of interest (ROIs) encompassing the left ventricle are either drawn manually or generated using an edge-detection program. Shown are computer-derived ROIs around the LV at end-diastole (A) and end-systole (B). ROIs are generated for all frames of the image set. After correcting for the contribution of background, a left ventricular time-activity curve is produced (C). Examining the curve, one can see that in the first frame (end-diastole) there are 20,000 counts in the left ventricle. The seventh frame has the fewest counts in the left ventricle (8,000) and is the end-systolic frame. The ejection frame is therefore 60%.

volume without adequate hypertrophy as can be seen in aortic regurgitation). This is characterized by a low ejection fraction with either a regional wall motion abnormality (CAD) or generalized reduction in systolic function (myocarditis, drug induced or idiopathic cardiomyopathy, aortic regurgitation). Heart failure may also occur because of increased resistance to ventricular filling referred to as diastolic dysfunction. This may be due to impaired relaxation (e.g., myocardial ischemia) or

Amplitude Phase

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Figure 6. Phase and amplitude images. The series of ERNA images can be analyzed in such a way as to generate images depicting the degree of pixel change between end-diastole (ED) and end-systole (ES) as well as the timing of pixel change. The top row depicts a normal patient with the amplitude image showing a horseshoe area of activity (long arrow) in the left ventricle (since the peripherally located LV pixels show the greatest change between the ED and ES). Similarly, a crescentic area is seen for the RV (short arrow). The phase image shows a similar gray color for both the left and right ventricles indicating that they contract simultaneously. In the lower row there is a low amplitude area (i.e., little change between ED and ES) inferoapically which on the phase image is seen to be "out of pahse" with the remaining ventricular mass implying that it is dyskinetic (arrowhead).

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