QUANTITATIVE ECHOTEXTURE ANALYSIS OF BOVINE CORPORA-LUTEA

A study was designed to evaluate the attributes of ultrasound images o f bovine ovarian CL throughout the estrous cycle. The ovaries of 8 hei fers were examined daily by transrectal ultrasonography for 2 interovu latory intervals (ovulation = Day 0). Ultrasonographic examinations of the ovaries were videotaped daily, and recorded images of the CL were digitized for computer analysis of echotexture (mean pixel value and heterogeneity). Blood samples were taken daily and to determine plasma progesterone concentrations. Corpora lutea were of 2 morphological ty pes, those with a central fluid-filled cavity (n = 6) and those withou t (n = 9). No differences were detected between CL with or without a f luid-filled cavity; therefore, data were combined. Mean pixel values o f ultrasound images of the CL changed (P = 0.0001) during the interovu latory interval; values decreased (P < 0.05) from Day 0 to Day 3 durin g early growth of the CL, reached a plateau when increases in luteal d iameter ceased, and decreased (P < 0.05) to minimal levels at the onse t of regression of the CL. The mean pixel value subsequently increased (P < 0.05) after Day 17 to values similar to those at the beginning o f the interovulatory interval. A time-dependent effect was not observe d for heterogeneity of images of the CL (P > 0.5). The results support ed the hypothesis that quantitative changes in luteal echotexture are reflective of changes in the physiologic status of the CL. (C) 1998 by Elsevier Science Inc.