Mayumi Takeuchi

Pathogenesis and MRI findings in two cases of seromucinous borderline tumors coexisting with carcinoma in endometriotic cysts: Case reports and literature review

Abstract Seromucinous borderline tumors (SMBTs) generally have a favorable prognosis, and fertility‐preserving surgery may be indicated. However, SMBT may occasionally coexist with carcinoma, necessitating careful management. This report presents two cases of SMBT coexisting with carcinoma within endometriotic cysts and reviews pathogenesis mechanisms with MRI‐pathological correlations. In both cases, SMBT components appeared as papillary or nodular projections with prominent high signal intensity on T2WI, no diffusion restriction on DWI, and gradual, weak enhancement on dynamic contrast‐enhanced (DCE) MRI. In contrast, coexisting carcinoma components showed intermediate signal intensity on T2WI, diffusion restriction on DWI, and rapid, intense enhancement on DCE‐MRI. As it affects prognosis and treatment strategy, assessing the coexistence of carcinoma with SMBT is essential. This is the first report to demonstrate the usefulness of multiparametric MRI, including DWI and DCE‐MRI, in evaluating SMBT and coexisting carcinoma in endometriotic cysts.

Improved diagnosis of adnexal lesions by integrating intra-tumoral hemorrhage detection with non-contrast MRI scoring (NCMS) using susceptibility-weighted sequences

Background Dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) protocol was included into the Ovarian-Adnexal Reporting & Data System (O-RADS) MRI scoring system. To avoid the administration of contrast medium, the non-contrast MRI scoring (NCMS) system was proposed. Purpose To evaluate the contribution of detecting intra-tumoral hemorrhage in the solid tissue of adnexal masses to improve tumor characterization and enhance the risk stratification of adnexal lesions using the NCMS system. Material and Methods MRI findings including susceptibility-weighted sequences (T2*-weighted MR angiography [SWAN]) were retrospectively analyzed in 126 surgically confirmed adnexal tumors with solid tissue components (20 benign, 106 malignant). Solid tissue was classified as malignant based on the NCMS criteria, defined by intermediate intensity on T2-weighted (T2W) imaging, and corresponding diffusion restriction. Hemorrhage was assessed based on high intensity on T1-weighted (T1W) imaging and susceptibility-related signal voids on SWAN. Results The NCMS solid tissue criteria identified malignancy with a sensitivity of 94.3%, specificity of 60%, and accuracy of 88.9%. High intensity on T1W imaging and signal voids on SWAN were observed in 23.6% and 72.6% of malignant lesions, compared to 0% and 5% in benign lesions, respectively. Hemorrhage was frequently observed in high-grade malignant tumors, or hemorrhagic subtypes. The combination of NCMS criteria and/or presence of intra-tumoral hemorrhage was associated with malignancy, yielding a sensitivity of 98.1%, specificity of 60%, and accuracy of 92.1%. Conclusion The inclusion of intra-tumoral hemorrhage enhances the diagnostic accuracy of the NCMS for characterizing adnexal lesions. SWAN may also aid in estimating tumor grade and identifying hemorrhagic subtypes.

Dynamic contrast-enhanced MR imaging of uterine endometrial carcinoma with/without squamous differentiation

Endometrial carcinoma with strong enhancement on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is suggestive of high-grade type II endometrial carcinoma. However, low-grade type I endometrial carcinoma may also sometimes show strong enhancement. We hypothesized that squamous differentiation would contribute to the strong enhancement at the early phase on DCE-MRI-like uterine cervical squamous cell carcinoma and compared the DCE-MRI findings of endometrial carcinoma with and without squamous differentiation. DCE-MRI of endometrial carcinoma including 41 low-grade type I endometrial carcinomas without squamous differentiation (LG), 39 low-grade type I endometrial carcinomas with squamous differentiation (LGSD), and 20 high-grade type II endometrial carcinomas (HG) was retrospectively evaluated. Significant difference in the time-intensity curves was found between LG and HG and LG and LGSD, whereas no significant difference was seen between HG and LGSD. Curve type 3 (initial signal rise which is steeper than that of the myometrium) was more frequent in HG (60%) and LGSD (77%) than in LG (34%). It should be recognized as a pitfall that high-grade type II endometrial carcinoma and low-grade type I endometrial carcinoma with squamous differentiation may show similar early strong enhancement on DCE-MRI.

Susceptibility-weighted MR sequence for the evaluation of ovarian masses with torsion

Objective: Adnexal torsion is a rare gynecologic emergency caused by twisting of an adnexal mass. Twisted vascular pedicle is the most specific imaging finding for adnexal torsion, however, identification of twisted vascular pedicle can be challenging. The purpose of this study is to evaluate the feasibility of susceptibility-weighted MR sequence (SWS) for the diagnosis of adnexal torsion. Methods: MR imaging including SWS (SWAN: susceptibility-weighted angiography) of surgically proven four benign ovarian masses with torsion (one acute and three subacute to chronic torsions) were retrospectively evaluated. Three cystic masses and one solid mass were included in this study. Results: High signal intensity venous thrombus within the twisted vascular pedicle on T  1-weighted imaging (T  1WI) was detected in three lesions with subacute to chronic torsion (75%) but not in one lesion with acute torsion, whereas susceptibility-induced signal voids within the twisted vascular pedicle on SWAN were detected in all four lesions (100%). Conclusion: The demonstration of venous thrombus in the twisted vascular pedicle by SWS may be diagnostic for adnexal torsion. Advances in knowledge: SWS can detect blood products sensitively and can reveal venous thrombus in the twisted vascular pedicle, which may be helpful for the diagnosis of adnexal torsion.

Reduced field-of-view diffusion-weighted MR imaging for assessing the local extent of uterine cervical cancer

Background Recently, the evaluation of the tumor size and local extension of early-stage uterine cervical cancer on magnetic resonance imaging is important for the accurate clinical staging and to determine the indication of less extensive surgery such as fertility sparing radical trachelectomy. Purpose To compare the diagnostic ability of reduced field-of-view diffusion-weighted imaging with those of three-dimensional (3D) contrast-enhanced T1-weighted imaging and T2-weighted imaging for assessing the tumor margin delineation and local extent of uterine cervical cancer. Material and Methods 3T magnetic resonance images, including T2-weighted imaging, reduced field-of-view diffusion-weighted imaging, and 3D contrast-enhanced T1-weighted imaging, in 27 women with surgically proven cervical cancer (19 FIGO stage IB1, 3 IB2, and 5 IIA1) were retrospectively evaluated. Tumor margins and local tumor extent, including the presence of invasion to parametrium and vagina were evaluated on both sagittal and oblique axial (short axis) images; the results were compared with histologically confirmed tumor extension. Results Reduced field-of-view diffusion-weighted imaging diagnosed the tumor margins, which was more accurate than T2-weighted imaging ( P<0.001) and slightly better than 3D contrast-enhanced T1-weighted imaging. Reduced field-of-view diffusion-weighted imaging could define the tumor margins well even in small lesions (≤ 20 mm). Histological examination revealed parametrial invasion in two cases (clinically under-staged) and vaginal invasion in four cases. Reduced field-of-view diffusion-weighted imaging could demonstrate local extension of all lesions, which was more accurate than clinical examination and T2-weighted imaging. Conclusion Addition of reduced field-of-view diffusion-weighted imaging may improve the staging accuracy of magnetic resonance imaging for cervical cancer in assessing the local tumor extent.

The feasibility of reduced field-of-view diffusion-weighted imaging in evaluating bladder invasion of uterine cervical cancer

Objectives: Uterine cervical cancer with bladder mucosal invasion is classified as FIGO stage IVA with poor prognosis. MRI can rule out the bladder invasion and skipping cystoscopy may be possible; however, high false-positive rate may be problematic. The purpose of this study is to evaluate the diagnostic performance of reduced field-of-view (FOV) diffusion-weighted imaging (DWI) in evaluating bladder mucosal invasion of cervical cancer. Methods: 3T MRI including T2WI and reduced FOV DWI in 15 women with histologically proven cervical cancer (two stage IIIB, six stage IVA, seven stage IVB) were retrospectively evaluated compared with cystoscopic findings. Results: Cystoscopy revealed mucosal invasion in 13 of 15 cases. The border between the tumor and the bladder wall was unclear on T2WI and clear on reduced FOV DWI in all 15 cases. The diagnosis of mucosal invasion on reduced FOV DWI had a sensitivity of 100%, specificity of 50%, accuracy of 93%, PPV of 93%, and NPV of 100%. Conclusions: Addition of reduced FOV DWI may improve the staging accuracy of MRI for cervical cancer in assessing the bladder mucosal invasion. Advances in knowledge: Reduced FOV DWI may improve the staging accuracy of cervical cancer in assessing bladder mucosal invasion with high NPV and PPV, which may be helpful for avoiding unnecessary cystoscopy.