Accuracy of MRI for adolescent adnexal torsion in ultrasound-equivocal cases: correlation of imaging features with surgical confirmation.

AIM: Although MRI studies report sensitivity and specificity rates of 80-90 % in acute adnexal torsion, the proportion of patients without torsion undergoing emergency surgery following pelvic MRI is significantly higher. This study aims to compare MRI findings between surgically confirmed torsion-positive and torsion-negative cases.

MATERIALS AND

METHODS

Paediatric patients who underwent pelvic MRI and emergency surgery were retrospectively reviewed. Thirteen distinct MRI features were visually scored. Additionally, measurements of both ovaries, ADC values, the stromal thickness of the affected ovary, and the predisposing lesion were recorded. Two paediatric radiologists independently evaluated the images without knowledge of surgical outcomes. In cases of disagreement, a final consensus was reached with the involvement of an experienced abdominal radiologist.

RESULTS

Among 64 surgically treated patients, 31 (48.4 %) had torsion. MRI of 58 patients (29 torsion-positive) was deemed of sufficient quality. All categorical variables significantly differed between groups, with the most indicative feature being the presence of a twisted pedicle (p<0.05). Differences were observed in T2-weighted, T1-weighted, and post-contrast ovarian parenchymal findings (p<0.05), whereas free fluid (p=0.352) and predisposing cysts (p=0.467) did not show significant differences. Ovarian size, volume, and ADC measurements were significantly different (p<0.05). ROC analysis identified stromal thickness as the most discriminative, with an AUC of 0.85.

CONCLUSIONS

In cases where ultrasound is inconclusive, MRI provides high accuracy and interobserver agreement for acute adnexal torsion. While all ovarian and pedicle-related findings were significantly different between groups, the most diagnostically relevant features were the presence of a twisted pedicle, increased ovarian long-axis diameter, stromal thickening, and T2-weighted hypointense stroma.