The myometrial‐cervical ratio (MCR): Assessing the diagnostic accuracy of a novel ultrasound measurement in the diagnosis of adenomyosis

Adenomyosis is histologically defined by the presence of endometrial glands and stroma in the myometrium. To date, there are no standardised ultrasound findings that reliably predict histological adenomyosis.This study aimed to determine the diagnostic accuracy of a novel sonographic measurement for adenomyosis, the myometrial-cervical ratio (MCR), when compared with histopathological diagnosis.A single-centre retrospective study was performed. The MCR was calculated from the pre-operative ultrasound, and histopathology reviewed for each case. Accuracy data were analysed in the form of 2 × 2 tables. The discriminative value of the MCR was summarised with a receiver operator characteristic (ROC) curve. Sub-analysis examined the impact of fibroids, hormonal suppression, menopausal status, parity and indication for surgery.Between 1 January 2016 and 31 December 2018, 982 patients underwent hysterectomy for benign non-obstetric indication and adequate pre-operative ultrasound was available for 260. The MCR demonstrated limited diagnostic ability for adenomyosis (area under the receiver operating characteristic curve (AUROC) 0.58, 95% CI 0.51-0.65). However, when applied to cases with no uterine fibroid included in the MCR calculation (n = 133) there was a strong association between MCR and diagnosis of adenomyosis (odds ratio: 5.79, 95% CI: 2.15, 15.62, P = 0.001) with AUROC for this model 0.68 (95% CI: 0.59, 0.77). At an MCR cut-point of 1.74, sensitivity is 67.16% and specificity is 66.15%, with 66.67% of samples correctly classified.While diagnostic accuracy was suboptimal, the MCR outperforms traditional ultrasound diagnostic features of adenomyosis. The MCR may offer a simple imaging measurement for adenomyosis.