Accuracy of Transvaginal Ultrasonographic Diagnosis of Retroflexed Uterus in Endometriosis, with Magnetic Resonance Imaging as Reference

BACKGROUND

Accurate diagnosis of retroflexed uterus in daily practice is essential because this condition is related to pelvic pain and deep endometriosis. Uterine flexion can be measured by transvaginal ultrasonography (TVUS), a cost-effective primary test, but the accuracy required for diagnosing retroflexed uterus is unclear. This study assessed the accuracy of TVUS for diagnosis of retroflexed uterus in patients with endometriosis and compared it with that of magnetic resonance imaging (MRI) -the gold standard for measuring the uterine axis.

METHODS

The study included 123 patients who underwent endometriosis surgery in our department between 2012 and 2017. Uterine flexion angles were measured by retrospectively examining TVUS and MRI images, and the correlation was analyzed. Analysis of anteverted and retroverted uterine subgroups identified aspects of diagnosing uterine flexion with TVUS.

RESULTS

Uterine flexion angles on TVUS were strongly positively correlated (r = 0.86) with MRI results. Additionally, TVUS yielded no false-positive diagnoses and 28 false-negative diagnoses of retroflexion. All false-negative diagnoses occurred in patients with anteverted retroflexed uteruses.

CONCLUSIONS

TVUS was generally accurate for measuring uterine flexion angle, as indicated by its strong correlation with MRI. Misdiagnosis of anteverted retroflexed uterus was a limitation of using TVUS for retroflexion diagnosis.

Acute pelvic pain: A pictorial review with magnetic resonance imaging

Acute uterine emergencies constitute both obstetric and gynecologic conditions. The superior image resolution, superior soft-tissue characterization, and lack of ionizing radiation make magnetic resonance imaging (MRI) preferable over ultrasonography (USG) and computed tomography (CT) in investigating uterine emergencies. Although USG is the first-line imaging modality and is easily accessible, it has limitations. USG is an operator dependent and limited by patient factors such as obesity and muscle atrophy. CT is limited by its risk of teratogenicity in pregnant females, poor tissue differentiation, and radiation effect. The non-specific findings on CT may lead to misinterpretation of the pathology. MRI overcomes all these limitations and is emerging as the most crucial imaging modality in the emergency room (ER). The evolving 3D MR sequences further reduce the acquisition times, expanding its ER role. Although MRI is not the first-line imaging modality, it is a problem-solving tool when the ultrasound and CT are inconclusive. This pictorial review discusses the various MRI techniques used in uterine imaging and the appearances of distinct etiologies of uterine emergencies across different MRI sequences.