Oblique NMR imaging of the uterus in macaques: Uterine response to estrogen stimulation

We report methods for quantitative NMR imaging of the primate uterus and the application of these methods of measuring the response of the monkey (Macaca nemestrina) uterus (endometrial volume, myometrial volume, T2 values, myometrial junction zone) to estrogen stimulation. High-field (2.35 T), fat-suppressed, T2-weighted (TE50) oblique methods were used. Slice thickness, location, and angle were varied on each examination to obtain six contiguous slices between the cervix and fundus, regardless of size or orientation of the uterus. Basal endometrial and myometrial volumes were 0.05 ± 0.01 cm3 and 1.31 ± 0.23 cm3 in chronically ovariectomized animals. These increased by 15.7 ± 3.6-fold and 3.1 ± 0.4-fold, respectively, during 7 days of estrogen stimulation (estradiol benzoate, 5 μg/kg sc daily) while myometrial T2 increased from 52 ± 1 to 67 ± 4 ms. These changes reversed following menstrual bleeding.