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Accuracy of quantitative ventriculographic analysis at reduced frame rates
1Cardiovascular Research and Training Center, University of Washington, Seattle, Washington 98195-6422, USA.
Objective:
We measured the error in left ventricular (LV) volume and wall motion measurement from recording contrast ventriculograms at 15 frames/sec instead of 30 frames/sec.
Background:
Angiograms are increasingly recorded at 15 frames/sec instead of 30 frames/sec to improve efficiency. However the resulting error in quantitative analysis has not been evaluated.
Methods:
Contrast ventriculograms recorded at 30 frames/sec of 23 patients undergoing diagnostic studies were digitized from cine film. End diastolic volume (EDV), end systolic volume (ESV), ejection fraction, anterior wall motion, and inferior wall motion were measured from a full set recorded at 30 frames/sec and from two reduced data sets at 15 frames/sec generated from the even and odd numbered frames. Intraobserver variability was compared with the error due to frame rate reduction.
Results:
The error due to frame rate reduction did not differ significantly from intraobserver variability (p > 0.1 for all), measuring 2.6 +/- 2.2 ml (r = 0.997) vs. 1.9 +/- 1.2 ml (r = 0.999), respectively for EDV, 2.4 +/- 1.8 ml (r = 0.991) vs. 2.1 +/- 1.7 ml (r = 0.994), respectively for ESV, and 0.2 +/- 0.2 percent (r = 0. 981) vs. 0.1 +/- 1.2 percent (r = 0.994), respectively for ejection fraction. The error and variability for wall motion were 0.3 +/- 0.3 SD (r = 0.928) vs. 0.2 +/- 0.1 SD (r = 0.946), respectively for the anterior wall and 0.2 +/- 0.2 SD (r = 0.963) vs. 0.2 +/- 0.1 SD (r = 0.968), respectively for the inferior wall.
Conclusion:
Imaging the LV at 15 frames/sec does not cause a significant error in measuring LV volume and function compared with imaging at 30 frames/sec. Cathet. Cardiovasc, Intervent. 48:18-21, 1999.