The myometrial-cervical ratio: Can a simple sonographic measurement improve diagnosis of adenomyosis in a regional setting?

Introduction: Adenomyosis is histologically defined by the presence of endometrial glands and stroma in the myometrium. Ultrasound findings of adenomyosis are being redefined to better diagnose adenomyosis pre-operatively.

Methods: A single-centre retrospective study was performed at a regional hospital. The myometrial-cervical ratio was calculated on pre-operative ultrasounds, and histopathology reviewed for each case. Logistic regression was used to estimate the association between the myometrial-cervical ratio and adenomyosis confirmed on histopathology, and the area under the receiver operating characteristic curve was calculated. Comparisons were performed based on the presence of fibroids on ultrasound.

Results: Complete data were available for 136 benign hysterectomies between 1 January 2015 and 31 December 2020. When the myometrial-cervical ratio was treated as a continuous variable in a logistic regression of adenomyosis on histopathology, there was no statistical evidence (χ²(1) < 0.01, p = 0.98) of an association. When cases including fibroids in the myometrial-cervical ratio were excluded, there was a non-significant association between myometrial-cervical ratio and adenomyosis on histopathology (odds ratio = 3.435, 95% confidence interval = 0.964, 12.235; χ²(1) = 3.62, p = 0.057); area under the receiver operating characteristic = 0.637 (95% confidence interval = 0.504, 0.770). The optimal myometrial-cervical ratio cutpoint was 1.875 (95% confidence interval = 1.698, 2.051), which achieved 71.43% sensitivity and 60.00% specificity. There was strong statistical evidence (χ²(1) = 9.02, p = 0.003) that the myometrial-cervical ratio outperformed standard pre-operative ultrasound identification of adenomyosis.

Conclusion: While accuracy remains suboptimal, the myometrial-cervical ratio outperformed standard ultrasound diagnostic features of adenomyosis in a regional setting. The myometrial-cervical ratio may offer a simple imaging measurement for adenomyosis in inexperienced hands when fibroids are absent.