1. An objective volumetric method for assessment of ovarian follicular and luteal vascular flow using colour Doppler ultrasonography.
- Author
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Caunce SL, Dadarwal D, Adams GP, Brar P, and Singh J
- Subjects
- Animals, Corpus Luteum cytology, Estrus Synchronization methods, Female, Gonadotropin-Releasing Hormone pharmacology, Hemodynamics, Imaging, Three-Dimensional veterinary, Luteal Cells cytology, Luteal Cells ultrastructure, Ovarian Follicle cytology, Ovary blood supply, Ovary cytology, Ovary diagnostic imaging, Ovulation physiology, Ovulation Detection methods, Ovulation Detection veterinary, Ovulation Induction methods, Ovulation Induction veterinary, Regional Blood Flow, Buffaloes, Corpus Luteum blood supply, Corpus Luteum diagnostic imaging, Ovarian Follicle blood supply, Ovarian Follicle diagnostic imaging, Ultrasonography, Doppler, Color methods, Ultrasonography, Doppler, Color veterinary
- Abstract
Our goal was to develop an objective computer-assisted volumetric method of assessing vascular flow from colour Doppler ultrasound data of ovarian structures recorded by free-hand movement. We hypothesized that a vascularity index (ratio of the region of blood flood to the region of ovarian structure) obtained from the three-dimensional volumetric analysis would be more precise (less variable) than conventional two-dimensional analysis of single images in estimating the functional status of the preovulatory follicles and corpus luteum. Doppler ultrasound cineloops of water buffaloes (Bubalus bubalis; n = 22) ovaries were recorded daily from 12 h before GnRH treatment to four days after ovulation. Cineloops were processed using Fiji and Imaris software packages for segmenting the area (two-dimensional analysis) and the volume (three-dimensional analysis) occupied by the blood-flow and associated tissue to calculate the vascularity index. For volumetric measurement, all images in a cineloop were used (i.e., no a-priori selection of images) while for two-dimensional analysis, three images from the region with apparent maximum vascularity were selected. The volumetric method was verified with theoretical ellipsoidal volume of the follicle (r = 0.96 P < 0.01) or corpus luteum (r = 0.58 P = 0.02). The variability in the follicular vascularity index among animals was lower using the volumetric method than two-dimensional analysis (0.018 ± 0.002 vs 0.030 ± 0.005, P < 0.01), while the variability for CL vascularity was similar between methods (P = 0.23). An increase in the follicular vascularity index was detected at 12 h after GnRH treatment using both methods (two-dimensional: 0.030 ± 0.008, P < 0.01; three-dimensional: 0.016 ± 0.006, P < 0.02). Buffaloes that ovulated tended to have a greater increase in 3D vascularity index than non-responding buffaloes (P = 0.06); the two-dimensional method was not able to detect these changes. Using the three-dimensional method, a moderate positive correlation (r = 0.59; P = 0.02) was evident between the follicular vascularity index at 14-16 h after GnRH treatment and follicular diameter. In conclusion, an objective volumetric method for assessing relative ovarian blood flow changes was developed using Doppler ultrasound cineloops recorded by free-hand movement. The 3-dimensional method eliminates the need for a-priori selection of images and is more precise as a result of decreased technical variability., (Copyright © 2019 Elsevier Inc. All rights reserved.)
- Published
- 2019
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