Investigating the diagnostic value of quantitative parameters based on T2-weighted and contrast-enhanced MRI with psoas muscle and outer myometrium as internal references for differentiating uterine sarcomas from leiomyomas at 3T MRI

Abstract

Background Post-hysterectomy histopathological examination is currently the main diagnostic tool for differentiating uterine sarcomas from leiomyomas. This study aimed to investigate the diagnostic accuracy of preoperative quantitative metrics based on T2-weighted sequences and contrast-enhanced MRI (CE-MRI) for distinguishing uterine sarcomas from leiomyomas. Materials and methods The institutional review board approved the study. Sixty-five women confirmed to have a total of 105 lesions participated. Routine pelvic MRI sequences, T2 map and CE-MRI images were performed preoperatively using a 3 T MR scanner. Six quantitative metrics—T2 mapping parameter, T2 scaled ratio, tumor myometrium contrast ratio on T2, tumor psoas contrast ratio on T2, tumor myometrium contrast-enhanced ratio, and tumor psoas contrast-enhanced ratio—were extracted from the acquired image sets. Chi-square test was used to compare the percentage of malignant lesions with the central necrosis to the corresponding percentage for the benign masses. Using the area under receiver operating characteristic (AUC) curve, the performance of different metrics for distinguishing uterine sarcomas from leiomyomas was measured. Moreover, for each metric, we extracted the optimal cut-off value. The values of sensitivity, specificity, negative predictive value, and positive predictive value were calculted for the classifiers based on different metrics. Results The average age, average lesion size, and proportion of premenopausal women in benign and malignant groups were comparable in our dataset. The signal intensity of uterine sarcomas at T2-weighted sequences was significantly higher than that of leiomyomas ( p < 0.001), while intensity at T1-weighted sequences exhibited no significant difference between the two masses ( p = 0.201). Our data also suggested that a central necrosis was ten times more common among malignant lesions compared to benign ones ( p < 0.001). Among different metrics, T2 mapping parameter achieved the highest AUC value and accuracy in differentiating two groups. Three measures—T2 scaled ratio, tumor myometrium contrast ratio on T2, and tumor myometrium contrast-enhanced ratio—achieved a sensitivity of 100%, therefore none of the malignant lesions would have been missed if these metrics had been adopted in patient management. Conclusions The findings suggested that the evaluated metrics could be useful in the preoperative assessment of myometrial masses to differentiate uterine sarcomas from leiomyomas. The proposed framework has major implications for improving current practice in the management of myometrial masses.

Differentiating cellular leiomyoma from uterine sarcoma and atypical leiomyoma using multi-parametric MRI

“…Uterine LMs are histologically composed of smooth muscle cells with little or no mitotic activity; on the other hand, CLs were defined as an atypical subset of uterine leiomyomas with higher cellularity than the adjacent myometrium. In clinic, diagnosis of typical LMs is not difficult when lesions in uterine have imaging characteristics, such as isointense T1 signal with regular morphology and well-defined margins ( 15 ). However, when LMs present atypical imaging manifestations, particularly with degeneration, the accurate differentiation will be very challenging ( 16 , 17 ).…”

Advances in the Preoperative Identification of Uterine Sarcoma

“…LMS can exhibit a high T1 signal [ 45 ], but a high T1 signal can also occur when uterine fibroids are associated with hemorrhage. Therefore, a study [ 46 ] did not find a significant difference in T1 presentation between uterine sarcomas and uterine fibroids. A high T1 signal within LMS exhibits more heterogeneity, poorly defined boundaries, greater occupancy, and lower signal intensity (SI) than a high T1 signal within uterine fibroids [ 47 ].…”

“…However, some uterine leiomyomas with different degenerations (cystic, mucinous, and effusion) or cellular histological subtypes can also exhibit a high SI on T2-weighted imaging (T2WI) [ 52 ], which makes it difficult to determine the benignity or malignancy of uterine tumors. When combining the three measurements of T2 ratio, tumor-myometrial contrast on T2, and tumor-myometrial contrast enhancement ratio, sensitivity can reach 100% without missing any malignant lesions [ 46 ]. Namimoto et al [ 53 ] quantified the SI of tumors on T2WI as the tumor-myometrial contrast ratio (TCR) by using the formula.…”

World Federation for Ultrasound in Medicine Review Paper: Incidental Findings during Obstetrical Ultrasound

“…MRI contributes to the overall imaging approach to incidentalomas during pregnancy, First, its can be invaluable in the differential diagnosis between benign and malignant ovarian masses (Malek et al 2019). Indeed, MRI may be a completely reliable therapeutic modality with which to differentiate benign and malignant ovarian masses.…”