Corpus Luteum Morphology and Vascularization Assessed by Transvaginal Two-dimensional and Three-dimensional Ultrasound

Abstract

Abstract Background Our aim was to describe the corpus luteum morphology by two-dimensional ultrasound correlated by its vascularization and volume by 3D ultrasound and study the possible relationship between serum progesterone levels and the corpus luteum morphology. Methods Thirty-eight women were included in an intrauterine insemination program (IUI) in Santa Cristina University's Hospital. All the patients were evaluated in mesoluteal phase, the day +7 after hCG administration, by two-dimensional and three-dimensional ultrasound. The volume and vascular indices of the corpus luteum were calculated off-line using virtual organ computer-aided analysis (VOCALTM) software. Results Four different morphologies were described in the corpus luteum: echo-positive, echo-negative or sonoluscent, mixed echogenicity or nonvisible. Corpus luteum with mixed echogenicity was the most frequent one with 37.5% (12 cases). The corpus luteum vascular indices change in each morphology type, but there was statistically significant association just in vascularization index between echo-negative and mixed echogenicity corpus luteum morphologies, with p = 0.034. The rest of vascular indices do not change in each morphology corpus luteum types. There was statistically significant difference in mean gray value between echo-negative and mixed echogenicity morphologies, with p = 0.007. There were no statistically significant correlations between the corpus luteum morphology and the corpus luteum volume of any of the different types. There either was no statistically significant correlation between the corpus luteum morphology and progesterone serum levels on day +7 postovulation. Conclusions The mixed echogenicity corpus luteum morphology has more vessels and more cell mass than echo-negative ones. Progesterone serum levels in mid-luteal phase has no influence in corpus luteum morphology and vascularization.