MRI features of ovarian teratomas with somatic-type malignancy and mature cystic teratomas.

PURPOSE: We evaluated the magnetic resonance imaging (MRI) features of ovarian teratomas with somatic-type malignancy (TSMs) and benign ovarian mature cystic teratomas (MCTs) to determine the diagnostic contribution of the MRI findings for differentiating these two teratomas. METHODS: We compared the MRI findings between ovarian TSMs (n = 10) and MCTs (n = 193), and we conducted a receiver operating characteristic (ROC) analysis to determine the MRI findings' contribution to the differentiation of TSMs from MCTs. RESULTS: The maximum diameters of whole lesion and the largest solid component in the TSMs were larger than those of the MCTs (p = 0.0001 and p < 0.0001, respectively). Fat tissue in solid components was seen in 73/116 (62.9%) MCTs but in none of the TSMs (p = 0.0001). Ring-like enhancement in solid components was seen in 60/116 (51.7%) MCTs and none of the TSMs (p = 0.0031). On dynamic contrast-enhanced MRI (DCE MRI), all of the solid components in the TSMs showed a high- or intermediate-risk time intensity curve (TIC), and those in 113 of the 116 (97.4%) MCTs showed a low-risk TIC (p < 0.0001). The area under the curve of the ROC analysis using the high-/intermediate-risk TIC on DCE MRI was the highest (0.99) for differentiating TSMs from MCTs: sensitivity 100%, specificity 97.4%, positive predictive value 75.0%, negative predictive value 100%, and accuracy, 97.6%. CONCLUSION: Compared to ovarian MCTs, ovarian TSMs are larger and have larger solid components with high- or intermediate-risk TICs on DCE MRI. Ovarian MCTs frequently show small solid components with fat tissue, ring-like enhancement, and a low-risk TIC on DCE MRI.

MRI Findings and Differential Diagnosis of Anterior Mediastinal Solid Tumors.

The anterior mediastinum is the most common location of mediastinal tumors, and thymic epithelial tumors are the most common mediastinal tumors. It is important to differentiate thymic epithelial tumors from malignant lymphomas and malignant germ cell tumors because of the different treatment strategies. Dynamic contrast-enhanced MRI and diffusion-weighted imaging can provide additional information on the differential diagnosis. Chemical shift imaging can detect tiny fat tissues in the lesion and is useful in differentiating thymic hyperplasia from other solid tumors such as thymomas. MRI findings reflect histopathological features of mediastinal tumors, and a comprehensive evaluation of MRI sequences is important for estimation of the histopathological features of the tumor. In this manuscript, we describe the MRI findings of anterior mediastinal solid tumors and the role of MRI in the differential diagnosis.

Time to enhancement of breast lesions and normal breast parenchyma in light of menopausal status and menstrual cycle for ultrafast dynamic contrast-enhanced MRI using compressed sensing.

PURPOSE: To assess the dependency of the Time to enhancement (TTE) of breast lesions and normal breast parenchyma from menopausal status and menstrual cycle using ultrafast compressed sensing (CS) -accelerated dynamic contrast-enhanced (DCE) MRI. METHODS: This institutional review board approved retrospective study included 89 breast cancers, 22 benign lesions and 131 normal breast parenchymal foci. A prototypical ultrafast DCE sequence obtained 30 phases with 2.9 s temporal resolution. Mean and median TTE of all breast cancers, benign lesions and normal breast parenchymal foci were assessed. we also assessed whether there were any differences in TTE regarding the menopausal status and menstrual cycle. RESULTS: The TTE of breast cancer was significantly shorter than that of benign lesions and normal breast parenchymal foci in both the premenopausal status (5.8 vs. 8.7 and 8.7 s, respectively) (p = 0.0028 and < 0.0001, respectively) and postmenopausal status (5.8 vs. 11.6 and 11.6 s, respectively) (p < 0.0001 in both). The TTE of parenchymal foci in the premenopausal status was significantly shorter than that in the postmenopausal status (p = 0.0025). Although the TTE interval between cancer and parenchymal foci in premenopausal status is shorter than that in postmenopausal status, the AUCs in the pre- and postmenopausal status for differentiating breast cancer and parenchymal foci were comparable with using different cutoff TTE values. There were no differences in TTE regarding the menstrual cycle. CONCLUSIONS: The TTE derived from ultrafast CS-accelerated DCE MRI was useful to differentiate breast cancer from benign lesions and normal breast parenchymal foci in both pre- and postmenopausal status.

A case of congenital capillary proliferation of the kidney (CCPK).

We report a case of congenital capillary proliferation of the kidney (CCPK) along with the multimodality imaging findings. Four-day-old boy who had managed due to his mother's gestational diabetes underwent abdominal ultrasound and a mass was detected in the right kidney. On gray scale ultrasound, the mass exhibited a hyperechoic, slight lobulated shape and a circumscribed margin. On Doppler mode, the mass showed hypervascularity in its peripheral to central zones. On MRI, the mass was hyperintense on the T2-weighted image, and no diffusion restriction was noted on DWI/ADC. On computed tomography, strong enhancement was shown at center of the mass at the post-contrast early phase; homogeneous enhancement at the entirety of the mass was observed at the delayed phase. We suspected hemangioma but did not rule out the possibility of malignancy. Surgery was performed. Pathologically, the specimen showed a proliferation of capillaries which were positive for vascular endothelial markers and negative for GLUT1 in immunohistochemistry. A small number of entrapped tubules and glomeruli were also observed. After an intensive pathological examination, the diagnosis of CCPK was finally considered. CCPK was recently described as an extremely rare childhood renal vascular lesion, and to our knowledge, only five other cases have been reported. Our patient's multimodality imaging findings well reflected the characteristics of a vascular lesion.

Relationship between MRI findings and invasive breast cancer with podoplanin-positive cancer-associated fibroblasts.

OBJECTIVE: Purpose of our study is to assess the relationship between MRI findings and invasive breast cancer (IBC) with cancer-associated fibroblasts (CAFs) that are positive for podoplanin. METHODS: We retrospectively analyzed the consecutive 109 IBCs. The IBCs were dichotomized as with (+) or without (-) podoplanin-positive CAFs. In MRI analyses, the dichotomized IBCs were compared the lesion to muscle ratio (L/M ratio) in STIR images, the ADC value, the distribution of kinetic parameters, and morphological findings. RESULTS: Of the 109 IBCs, 28 (26%) IBCs had podoplanin(+) CAFs. Compared to the podoplanin(-) group, the podoplanin(+) group tended to have a more malignant pathological status. In the STIR images, the podoplanin(+) group had significantly higher L/M ratio (7.59 vs. 6.55, p = 0.040). In a dynamic study, the podoplanin(+) group had a significantly higher percentage of the washout pattern (42.21% vs. 29.43%, p = 0.045). There were 23 mass lesions and 5 non-mass enhancement (NME) lesions in the podoplanin(+) group, and 69 mass lesions and 12 NME lesions in the podoplanin(-) group. The mass lesions of the podoplanin(-) group had a significantly higher likelihood of showing an irregular shape (n = 47 vs. 8, p = 0.035). The podoplanin(+) group's lesions had a significantly higher likelihood of showing a circumscribed margin (n = 14 vs. 6, p < 0.001) and a rim enhancement (n = 10 vs. 13, p = 0.047). In multivariate analyses, only high nuclear grade was significant predictive value of podoplanin(+) CAFs. CONCLUSION: Although not significant in multivariate analyses, MRI findings may be used to determine the podoplanin-positive CAF status of invasive breast cancer.

Anterior mediastinal lesions: CT and MRI features and differential diagnosis.

Anterior mediastinum is the most common location of mediastinal tumors, which include various solid and cystic lesions. The lesion location and CT and MRI features are important in the differential diagnosis. Recently, CT-based mediastinal compartment classification systems were proposed and suggested to be useful for accurate evaluation of mediastinal lesions. CT and MRI reflect the pathological findings of mediastinal lesions, and knowledge of the pathological features is important for the differential diagnosis. In this article, we review the CT and MRI features of anterior mediastinal lesions and describe important points in the differential diagnosis.

Maximum slope of ultrafast dynamic contrast-enhanced MRI of the breast: Comparisons with prognostic factors of breast cancer.

PURPOSE: To determine the relationship between the maximum slope (MS) of ultrafast dynamic contrast-enhanced (DCE)-MRI and prognostic factors of breast cancer. METHODS: One hundred thirteen patients with 118 breast cancers were included in this study. The ultrafast DCE sequence was acquired using a higher parallel imaging factor. Its spatial resolution was 0.9 × 0.9 × 2.5 mm and its temporal resolution was 8.3 s/phase. Each lesion was automatically segmented, and the ROI of highest enhancement in the lesion was identified. In this ROI, the MS was calculated. The MS of each lesion was compared with various prognostic factors of breast cancer. RESULTS: The MS of invasive cancer (median: 9.81%/sec) was significantly higher than that of ductal carcinoma in situ (median: 7.26%/sec) (p = 0.001). In the ROC analysis, the area under the ROC curve (AUC) was 0.7295. The MS of invasive cancer with axillary lymph node (LN) metastasis (median: 11.97%/sec) was significantly higher than that without axillary LN metastasis (median: 9.425%/sec) (p = 0.0024). In the ROC analysis, the AUC was 0.7177. In addition, the MS became significantly higher as the level of the proliferation marker ki-67 increased (correlation coefficient: 0.3317) (p = 0.0009). CONCLUSIONS: MS of ultrafast DCE-MRI is useful for predicting the prognostic factors of breast cancer. Higher maximum slope (MS) is significantly associated with an invasive breast cancer component. Higher MS is significantly associated with an axillary lymph node metastasis. MS becomes significantly higher with increasing ki-67 (a proliferation marker). Ultrafast MRI is useful for predicting the prognostic factors of breast cancer.

Tumor-stromal ratio (TSR) of invasive breast cancer: correlation with multi-parametric breast MRI findings.

OBJECTIVE: To correlate the tumor-stromal ratio (TSR) of invasive breast cancer and MRI findings. METHODS: This study was approved by our institutional review board. 126 consecutive patients with surgically proven invasive breast cancer were included. All patients underwent MRI exams including short-tau inversion-recovery (STIR) T 2 weighted imaging, diffusion-weighted imaging (DWI) and post-contrast dynamic imaging. The mean signal intensity (SI) and apparent diffusion coefficient (ADC) value of each lesion were measured. To objectively evaluate the STIR images, the ratio of the SI of the lesion to the muscle (L/M ratio) was also measured. Percentages of MRI kinetic parameters obtained from dynamic images were also measured. The TSR was defined as the percentage of the stromal component, and categorized into high-stroma (> 50%) and low-stroma (< 50%) groups. Intergroup differences in the SI, L/M ratio, ADC value and percentages of kinetic parameters were examined. RESULTS: The SI and L/M ratio of the high-stroma group were significantly lower than those of the low-stromal group (208.64 vs 331.86 for SI, 5.69 vs 9.31 for L/M ratio) (p < 0.001). The high-stroma group had significantly lower percentages of a washout pattern (25% vs 34.7 %) (p = 0.012) and significantly higher percentages of a persistent pattern (36.92% vs 28.26 %) (p = 0.044). There were no significant correlations between the TSR and ADC value. CONCLUSION: STIR and dynamic sequence of breast MRI reflects the stromal component of invasive breast cancer. ADVANCES IN KNOWLEDGE: This is the first study to correlate TSR and MRI findings. STIR and post-contrast dynamic study correlated with the stromal component of breast cancer.

CT-based mediastinal compartment classifications and differential diagnosis of mediastinal tumors.

Division of the mediastinum into compartments is used to help narrow down the differential diagnosis of mediastinal tumors, assess tumor growth, and plan biopsies and surgical procedures. There are several traditional mediastinal compartment classification systems based upon anatomical landmarks and lateral chest radiograph. Recently, the Japanese Association of Research of the Thymus (JART) and the International Thymic Malignancy Interest Group (ITMIG) proposed new mediastinal compartment classification systems based on transverse CT images. These CT-based classification systems are useful for more consistent and exact diagnosis of mediastinal tumors. In this article, we review these CT-based mediastinal compartment classifications in relation to the differential diagnosis of mediastinal tumors.

CT and MRI findings of thymic carcinoid.

OBJECTIVE: To evaluate the CT and MRI findings of thymic carcinoid and to compare these findings with previously published findings of thymoma. METHODS: 11 cases of pathologically proven thymic carcinoid were reviewed retrospectively. Three patients had typical carcinoid, and eight patients had atypical carcinoid. The characteristics of the tumours and related thoracic abnormalities were assessed in each case on CT and/or MRI by two chest radiologists. The final decisions on the findings were reached by consensus. RESULTS: Thymic carcinoids were more likely to have a large mass (ranging from 18 to 105 mm), irregular contours (n = 8), heterogeneous intensity on T2 weighted images (n = 6; eight patients underwent MRI), heterogeneous enhancement (n = 9) and local invasion (n = 7). A necrotic or cystic component was identified in seven patients (one typical carcinoid and six atypical carcinoids). Lymphadenopathy was seen in four patients. Septum, capsule, haemorrhage and calcification were seen in three patients, two patients, two patients and one patient, respectively, with atypical carcinoid. CONCLUSION: Thymic carcinoids tend to have a high prevalence of large masses, irregular contours, heterogeneous intensity on T2 weighted images, heterogeneous enhancement and local invasion on CT and/or MRI. A necrotic or cystic component is often seen in atypical carcinoid. Advances in knowledge: Radiologic features of thymic carcinoid mimic those of high-risk thymomas and/or thymic carcinomas.

Diagnostic Performance of Diffusion Tensor Imaging with Readout-segmented Echo-planar Imaging for Invasive Breast Cancer: Correlation of ADC and FA with Pathological Prognostic Markers.

PURPOSE: To assess the diagnostic performance of readout-segmented echo-planar diffusion tensor imaging (DTI based on rs-EPI) for breast cancer and to determine the correlation between the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values obtained from DTI based on rs-EPI with prognostic markers of invasive breast cancer. MATERIALS AND METHODS: This retrospective study examined 80 pathologically proven breast lesions (22 benign and 58 malignant lesions) of 80 patients who underwent both diffusion-weighted imaging based on single-shot echo-planar imaging (DWI based on ss-EPI) and DTI based on rs-EPI with b-values of 0 and 1000. We identified and compared the diagnostic performances of the DWI based on ss-EPI and the DTI based on rs-EPI using ADCs by conducting a receiver-operating-characteristics (ROC) analysis. We determined the correlations between the ADCs and the prognostic markers and those of the FA values and the same markers. RESULTS: The median ADCs of the benign and malignant lesions based on the ss-EPI were 1.57 and 1.2 × 10-3 mm2/sec, and those based on the rs-EPI were 1.53 and 1.09 × 10-3 mm2/sec, respectively. The area under the curve on the ROC analysis based on rs-EPI (0.924) was greater than that based on ss-EPI (0.897). There were no significant correlations between the ADCs and the prognostic markers, but there were significant correlations between the FA values and the estrogen receptor status, a proliferative marker, the nuclear grade and the intrinsic subtype. CONCLUSION: For breast cancer, DTI based on rs-EPI had superior diagnostic performance compared to DWI based on ss-EPI. Compared with the ADCs, the FA values were more closely correlated with prognostic markers of invasive breast cancer.

Diffusion weighted images of metastatic as compared with nonmetastatic axillary lymph nodes in patients with newly diagnosed breast cancer.

BACKGROUND: To investigate the ability of diffusion weighted images (DWI) to differentiate between metastatic and nonmetastatic axillary lymph nodes (LNs) in patients with newly diagnosed breast cancer. METHODS: From January 2010 to February 2012, DWI was performed at b values of 0 and 800 for 16 metastatic LNs from 16 patients with breast cancer, and 20 nonmetastatic LNs from 20 women without breast cancer. The metastatic LNs were proven by ultrasound (US) guided core biopsy and the same LNs were identified on MRI by comparing the US images with MR images. Nonmetastatic LNs were verified by the stability in size and shape for at least 2 years on MRI. The apparent diffusion coefficient (ADC) value of the metastatic and nonmetastatic axillary LNs was compared. Receiver-operating-characteristics (ROC) analysis was performed to evaluate the diagnostic performance of the ADC value in differentiating between metastatic and nonmetastatic axillary LNs. RESULTS: The mean ADC value was 0.746 × 10(-3) for metastatic LNs and 1.033 × 10(-3) for nonmetastatic LNs (P < 0.001). The area under the ROC curve was 0.884. The sensitivity and specificity for differentiating metastatic from nonmetastatic axillary LNs using a cutoff ADC value of 0.852 were 85% and 81%, respectively. CONCLUSION: There is a statistically significant difference between the ADC values of pathologically proven metastatic LNs and nonmetastatic LNs. DWI and ADC values are a useful tool for differentiating metastatic from nonmetastatic axillary LNs.

Magnetic resonance imaging manifestations of ovarian mullerian mixed epithelial borderline tumors: imaging and histologic features in comparison with mullerian mucinous borderline tumors.

We illustrate the magnetic resonance imaging features of 3 cases of rare ovarian Mullerian mixed epithelial borderline tumor (MEBT) and identify important diagnostic clues based on their detailed histologic, morphologic, and clinical features. Mullerian mixed epithelial borderline tumor has good prognosis, and adequate management is essential. In order to avoid unnecessary aggressive treatment, radiologists should become familiar with the imaging findings of MEBT. To the best of our knowledge, no articles have described the detailed images of MEBT.

Intratumoral heterogeneity of the distribution of kinetic parameters in breast cancer: comparison based on the molecular subtypes of invasive breast cancer.

PURPOSE: To evaluate the distribution pattern of kinetic parameters in breast cancers with various molecular subtypes. MATERIALS AND METHODS: This study was approved by institutional review board and was compliant with HIPAA. We classified 192 invasive breast cancers of 186 patients into four molecular subtypes using hormone receptor (HR) and human epidermal growth factor receptor 2 (HER2) results and evaluated the distribution pattern of kinetic parameters (percent volume of kinetic types relative to the tumor volume) in the molecular subtypes. RESULTS: In the delayed phase, all three types of kinetic parameter (persistent, plateau, and washout pattern) were observed in each molecular subtype without any dominant type of kinetic parameter. The percentages of washout pattern in the HR+ and HER2- type and triple negative (TN) cancers tended to be lower than those in the other molecular subtype cancers. CONCLUSION: Each molecular subtype of invasive breast cancer showed a heterogeneous kinetic pattern in dynamic-contrast magnetic resonance imaging (MRI). The HR+/HER2- cancers and the TN cancers had relatively lower percentages of washout pattern. When a manual assessment of the kinetic parameters is performed, close attention should be paid in order to identify the malignant washout kinetic pattern, particularly in HR+/HER2- cancer and TN cancer.

MR imaging of malignant primary breast lymphoma: including diffusion-weighted imaging, histologic features, and a literature review.

OBJECTIVE: To investigate the magnetic resonance (MR) imaging characteristics of malignant primary breast lymphoma (PBL), including features on diffusion-weighted imaging (DWI). METHODS: The MR findings of three patients were reviewed retrospectively at our institutions. The signal intensity, shape, enhancement pattern, and DWI findings were examined and correlated with the histologic features. We also reviewed the MR findings of cases of PBL reported in the literature. RESULTS: The tumors in our cases showed early enhancement with penetrating vessels on early-phase dynamic MR images and a strong high signal intensity on DWI. The tumors had a cerebroid appearance and septal enhancement on delayed contrast-enhanced MR images, and we speculate that the fibrous tissue seen in the tumors may correspond to septal enhancement. After chemotherapy, all lesions decreased in size, while the ADCs were increased. All of the cases reported in the literature showed early or avid enhancement; this finding was similar to that observed in our cases. CONCLUSIONS: Although based on a small number of cases, we suggest that strong enhancement with penetrating vessels in masses on early images of dynamic MR, strong high intensity on DWI, a cerebroid appearance, and septal enhancement are useful diagnostic clues for a diagnosis of PBL.