Prognostication of Ovarian Function after Ovarian Torsion Using Intraoperative Indocyanine Green Angiography

Abstract

To quantitatively evaluate the blood flow in ovaries (ischemic ovaries) that underwent torsion using indocyanine green angiography (ICGA) and assess the use of ICGA as an indicator for functional preservation of the ovaries. In vivo animal study. The University of Yamanashi Animal Experimentation Center. Eighteen female Wistar albino rats. As an alternative to ovarian torsion, we occluded an ovary in each rat for 24 hours, after which we performed ICGA before and after releasing ischemia and extracted the following 8 parameters: Fmax (maximum F value before releasing ischemia); Tmax (time taken from the onset of an increase in F to reaching Fmax); T½max (time taken from the onset of an increase in F to reaching half of Fmax); slope (Fmax/Tmax); time ratio (T½max/Tmax); F'max (maximum F value after releasing ischemia); reperfusion rate (F'max/Fmax); and reperfusion gap (F'max - Fmax). Four weeks later, we counted the total number of primordial and primary follicles and classified the rats into functional and nonfunctional groups. On the basis of the total number of primordial and primary follicles, 13 rats had "functional" ovaries on the clamped side, and 5 rats had "nonfunctional" ovaries. The area under the curve values for each parameter were as follows: Fmax, 0.908; Tmax, 0.569; T½max, 0.546; time ratio, 0.746; slope, 0.877; F'max, 0.723; reperfusion rate, 0.938; and reperfusion gap, 0.862. ICGA can be used to quantitatively evaluate ovaries that have been subjected to ischemia, and the magnitude of fluorescence intensity can be an excellent predictor of ovarian necrosis. Quantifying the degree of reperfusion immediately after the release of ischemia can be an equally excellent predictor of necrosis.