Modified MR scoring system for assessment of sonographically indeterminate ovarian and adnexal masses in the absence of dynamic contrast-enhanced

Abstract

Objectives: Dynamic contrast-enhanced (DCE) MRI is not available in all imaging centres to investigate adnexal masses. We proposed modified magnetic resonance (MR) scoring system based on an assessment of the enhancement of the solid tissue on early phase postcontrast series and diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) map and investigated the validity of this protocols in the current study.

Materials and methods: In this cross-sectional retrospective study, pelvic MRI of a total of 245 patients with 340 adnexal masses were studied based on the proposed modified scoring system and ADNEX MR scoring system.

Results: Modified scoring system with the sensitivity of 87.3% and specificity of 94.6% has an accuracy of 92.1%. Sensitivity, specificity, and accuracy of ADNEX MR scoring system is 96.6%, 91%, and 92.9%, respectively. The area under the receiver operating characteristic curve for the modified scoring system and ADNEX MR scoring system is 0.909 (with 0.870-0.938 95% confidence interval [CI]) and 0.938 (with 0.907-0.961 95% CI), respectively. Pairwise comparison of these area under the curves showed no significant difference (P = .053).

Conclusions: Modified scoring system is less sensitive than the ADNEX MR scoring system and more specific but the accuracy is not significantly different.

Advances in knowledge: According to our study, MR scoring system based on subjective assessment of the enhancement of the solid tissue on early phase postcontrast series and DWI with ADC map could be applicable in imaging centres that DCE is not available.

Keywords: ADNEX MR scoring system; adnexal mass; diffusion-weighted imaging; dynamic contrast-enhanced images; pelvic MRI.

Figure 1.

Flowchart of study population.

Figure 2.

Images from 43-year-old woman with left-sided solid-cystic adnexal mass indeterminate in transvaginal ultrasound. (A) Axial T1-weighted and (B) axial T2-weighted magnetic resonance (MR) images show left-sided multiloculated adnexal mass, with largest diameter of 85 mm, with intermediate signal-intensity locules and intermediate-high signal-intensity solid tissues. (C and D) Axial diffusion-weighted image showing, high signal intensity at b = 1000 s/mm² and low apparent diffusion coefficient signal intensity of solid enhancing tissues. (E and F) dynamic contrast-enhanced MRI yielded high risk time-intensity curve in comparison with adjacent external myometrium. Histology confirmed malignant granulosa cell tumour.

Figure 3.

ROC curve in the scoring systems.

Figure 4.

Images from 66-year-old woman with left-sided cystic adnexal mass indeterminate in transvaginal ultrasound. (A) Axial T1-weighted and (B) axial T2-weighted magnetic resonance (MR) images show left-sided multiloculated adnexal cystic mass, with largest diameter of 45 mm, with intermediate-high signal-intensity solid tissues. (C and D) Axial diffusion-weighted image showing, high signal intensity at b = 1000 s/mm² and high apparent diffusion coefficient signal intensity of solid enhancing tissues. (E and F) Dynamic contrast-enhanced MRI yielded type 2 time-intensity curve in comparison with adjacent external myometrium. In subjective assessment (G) enhancement of the solid parts is almost equal to external myometrium. This lesion was classified as score = 4 based on ADNEX MR scoring system and as score = 3 based on modified scoring system. Histology confirmed border line serous tumour.

Figure 5.

Images from 38-year-old woman with cystic adnexal mass on the left side. (A) Sagittal T2-weighted magnetic resonance (MR) images noted left-sided multiloculated adnexal mass, with largest diameter of 52 mm, with intermediate signal-intensity locules and intermediate-signal-intensity thickened and irregular internal septa. (B and C) Axial diffusion-weighted image showing, intermediate signal intensity at b = 1000 s/mm² and high apparent diffusion coefficient signal intensity of solid enhancing tissues. (D) In subjective assessment enhancement of the solid tissue is not more than external myometrium. Dynamic contrast-enhanced MRI (E and F) shows intermediate time-intensity curve with type-2 plateau in comparison with adjacent external myometrium. Histology proved benign infected endometrioma. ADNEX MR score was upgraded to 4 due to type-2 curve in modified scoring system the score is 3 as possibly benign.