Vessel morphology depicted by three-dimensional power Doppler ultrasound as a second stage test in difficult adnexal tumors: a prospective diagnostic accuracy study

Sladkevicius, P;Jokubkiene, L;Timmerman, D;Fischerova, D;Van Holsbeke, C;Franchi, D;Savelli, L;Epstein, E;Fruscio, R;Kaijser, J;Czekierdowski, A;Guerriero, S;Angela Pascual, M;Testa, A;Ameye, L;Valentin, L

2021-01-01

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Abstract

Objectives: The aim was to assess whether vessel morphology depicted by three-dimensional (3D) power Doppler ultrasound improves discrimination between benignity and malignancy if used as a second stage test in difficult adnexal masses. Methods: This is a prospective observational international multicenter diagnostic accuracy study. 2403 consecutive patients with an adnexal mass underwent standardized transvaginal 2D gray scale and color or power Doppler ultrasound and 3D power Doppler ultrasound by an experienced examiner. We defined a difficult tumor as one in which the logistic regression model IOTA LR1 yielded an ambiguous result (risk of malignancy 8.3% to 25.5%), or as one in which the ultrasound examiner was uncertain whether the tumor was benign or malignant when using subjective assessment. Even when the ultrasound examiner was uncertain he/she was obliged to classify the tumor as most likely benign or most likely malignant. For each difficult tumor, one researcher created a 360° rotating 3D image of the vessel tree in the whole tumor and another of the vessels tree in a 5 cm3 spherical volume selected from the most vascularized part of the tumor. Two other researchers, blinded to patient history, 2D ultrasound findings and histological diagnosis, independently described the vessel tree using predetermined vessel features. Their agreed classification was used. The reference standard was the histological diagnosis of the mass. We plotted the sensitivity of each test against 1 - specificity in a receiver operating characteristic diagram. The test with its symbol farthest from the reference line was considered to have the best discriminative ability. Results: There were 376/2403 (15.6%) difficult masses. Ultrasound volumes were available for 138 of these. In 79/138 masses the ultrasound examiner was uncertain about the diagnosis, in 87/138 IOTA LR1 yielded an ambiguous result, in 28/138 both methods gave an uncertain result. 38/138 (27%) masses were malignant. Among tumors difficult to classify by subjective assessment, the vessel feature 'densely packed vessels' had the best discriminative ability [sensitivity 67% (18/27), specificity 83% (43/52)] and was slightly superior to subjective assessment [sensitivity 74% (20/27), specificity 60% (31/52)]. In tumors in which IOTA LR1 yielded an ambiguous result, subjective assessment [sensitivity 82% (14/17), specificity 79% (55/70)] was superior to the best vascular feature, i.e. caliber changes of vessels in the whole tumor volume [sensitivity 71% (9/17), specificity 69% (48/70)]. Conclusion: Vessel morphology depicted by 3D power Doppler ultrasound may slightly improve discrimination between benign and malignant tumors difficult to classify by subjective assessment. For tumors in which the IOTA model LR1 yields an ambiguous result, subjective assessment is superior to vessel morphology as a second stage test.