The use of the myometrial-cervical ratio in the ultrasound diagnosis of adenomyosis - A validation study

BACKGROUND: Adenomyosis is a benign disorder defined by ectopic endometrial glands within the uterine myometrium. A study by Mooney et al reported the myometrial-cervical ratio (MCR), a novel ultrasound measurement that was found to improve the preoperative diagnosis of adenomyosis. AIMS: To validate the association between sonographic MCR and adenomyosis confirmed on histopathology in an independent patient group. MATERIALS AND METHODS: Single-centre retrospective cohort study including women who underwent hysterectomy between 1 January 2016 and 31 December 2018 for a benign, non-obstetric indication with an ultrasound at the study centre prior to surgery. Clinical details and histopathology were extracted. Ultrasound images were reviewed by a gynaecology ultrasound subspecialist blinded to histological findings. RESULTS: Eight hundred eighty-seven patients underwent hysterectomy in the study period for eligible indications; 317 had an ultrasound at the study centre and were included. There was no statistically significant association between the MCR and adenomyosis on histology when all patients were included; however, increased MCR was associated with adenomyosis when those with fibroids on ultrasound were excluded. The area under the receiver operating characteristic for this model was 0.614 (95% CI: 0.53 to 0.69). The optimal MCR cut-point in this subgroup was 1.79, which achieved 55.6% sensitivity and 62.8% specificity, with 58.5% correctly classified. There was no significant difference in MCR compared to traditional ultrasound markers of adenomyosis. CONCLUSIONS: In a population undergoing hysterectomy for benign and non-obstetric indications, the MCR applied to preoperative ultrasound was only weakly associated with a histological diagnosis of adenomyosis.