A METHOD FOR AUTOMATIC EDGE-DETECTION AND VOLUME COMPUTATION OF THE LEFT-VENTRICLE FROM ULTRAFAST COMPUTED TOMOGRAPHIC-IMAGES

RATIONALE AND OBJECTIVES. Detection of endocardial and epicardial bord ers of the left ventricle (LV) using various imaging modalities is tim e-consuming and prone to interpretive error, An automatic border detec tion algorithm is presented that is used with ultrafast computed tomog raphic images of the heart to compute cavity volumes. METHODS. The bas al-level slice is identified, and the algorithm automatically detects the endocardial and epicardial borders of images from the basal to the apical levels, From these, the ventricular areas and chamber volumes are computed, The algorithm uses the Fuzzy Hough Transform, region-gro wing schemes, and optimal border-detection techniques. The cross-secti onal areas and the chamber volumes computed with this technique were c ompared with those from manually traced images using canine hearts in vitro (n = 8) and studies in clinical patients (n = 27), RESULTS. Thou gh the correlation was good (r = .88), the algorithm overestimated the LV epicardial area by 4.8 +/- 6.4 cm(2), though this error was not st atistically different from zero (P > .05). There was no difference in endocardial areas (r = .95, P > .05), The algorithm tended to underest imate the end-diastolic volume (r = .94) and the end-systolic volume ( r = .94), although these errors were not statistically different from zero (P > .05), The algorithm tended to underestimate the ejection fra ction (r = .80), although this error was not statistically different f rom zero (P > .05), CONCLUSIONS. Automatic detection of myocardial bor ders provides the clinician with a useful tool for calculating chamber volumes and ejection fractions. The algorithm, with the corrections s uggested, provides an accurate estimation of areas and volumes, This a lgorithm may be useful for contour border identification with ultrasou nd, positron-emission tomography, magnetic resonance imaging, and othe r imaging modalities in the heart, as well as other structures.