Purpose: To determine magnetic resonance imaging (MRI) with readoutsegmented diffusion-weighted imaging (RESOLVE-DWI) and dual-energy computed tomography (DECT) features of sinonasal extramedullary plasmacytoma (SN-EMP). Methods:The MRI and/or DECT of 10 patients with SN-EMP confirmed by pathology were retrospectively reviewed. Apparent diffusion coefficient (ADC) values of RESOLVE-DWI were analyzed in 9 patients. The quantitative parameters derived from DECT, including the iodine concentration (IC), effective atomic number, and the slope (k) of spectral attenuation curve, were measured in 3 patients.Results: On conventional MRI, typical lesions were well defined (7 of 9), and isointense to the brain on both T1WI and T2WI (9 of 9). Most lesions presented with marked enhancement on contrast-enhanced T1WI without significant necrosis (8 of 9). Notably, multiple flow-void signals were observed in all lesions (9 of 9). On RESOLVE-DWI, the average ADC value was 0.55 Â 10 −3 mm 2 /s, and the normalized ADC value was 0.66 ± 0.04. On DECT, the average values of IC, effective atomic number, and slope (k) was 2.7 mg/mL, 8.62, and 3.8, respectively.Conclusions: Some typical MRI features (well-defined mass, isointensity to the brain, marked enhancement without obvious cystic changes, multiple flow voids, and a lower ADC value) strongly suggest the diagnosis of SN-EMP. The quantitative parameters derived from RESOLVE-DWI and DECT may provide more information for the diagnosis of SN-EMP.

Background: Chondrosarcoma in the mastoid is extremely rare, and it is easily misdiagnosed as a facial nerve schwannoma. background: Chondrosarcoma in the mastoid is extremely rare and it is easily misdiagnosed as a facial nerve schwannoma. Objective: To identify and compare computed tomography (CT) and magnetic resonance imaging (MRI) features of chondrosarcoma in the mastoid involving the facial nerve, including diffusion-weighted MRI characteristics, with those of facial nerve schwannoma. Method: CT and MRI features of 11 chondrosarcomas in the mastoid involving the facial nerve and 15 facial nerve schwannomas, confirmed by histopathology, were retrospectively reviewed. The tumor location, size, morphological features, bone change, calcification, signal intensity, texture, enhancement characteristics, the extent of lesions, and apparent diffusion coefficients (ADCs) were evaluated. method: CT and MRI features of 11 chondrosarcomas in the mastoid involving the facial nerve and 15 facial nerve schwannomas, confirmed by histopathology, were retrospectively reviewed. The tumor location, size, morphological features, bone change, calcification, signal intensity, texture, enhancement characteristics, extent of lesions, and apparent diffusion coefficients (ADCs) were evaluated. Results: On CT imaging, calcification could be found in 81.8% of chondrosarcomas (9/11) and 33.3% of facial nerve schwannomas (5/15). Chondrosarcoma in the mastoid appeared significantly hyperintense on T2-weighted images (T2WI) with low signal intensity septa in eight patients (72.7%, 8/11). After contrast, all chondrosarcomas showed inhomogeneous enhancement, and septal and peripheral enhancement could be found in six cases (54.5%, 6/11). Facial nerve schwannoma demonstrated inhomogeneous hyperintensity on T2WI in 12 cases (80%, 12/15), with obvious hyperintense cystic changes in seven cases. There were significant differences in calcification (P=0.014), T2 signal intensity (P=0.006), and septal and peripheral enhancement (P=0.001) between chondrosarcomas and facial nerve schwannomas. The ADCs of chondrosarcoma were significantly higher than those of facial nerve schwannomas (P<0.001). result: On CT imaging, calcification could be found in 81.8% of chondrosarcomas (9/11) and 33.3% of facial nerve schwannomas (5/15). Chondrosarcoma in the mastoid appeared significantly hyperintense with low signal intensity septa in eight patients (72.7%, 8/11). After contrast, all chondrosarcomas showed inhomogeneous enhancement, and septal and periphe on T2-weighted images ral enhancement could be found in six cases (54.5%, 6/11). On T2-weighted images, facial nerve schwannoma demonstrated inhomogeneous hyperintensity in 12 cases (80%, 12/15), with obvious hyperintense cystic changes in seven cases. There were significant differences in calcification (P=0.014), T2 signal intensity (P=0.006), and septal and peripheral enhancement (P=0.001) between chondrosarcomas and facial nerve schwannomas. The ADCs of chondrosarcoma were significantly higher than those of facial nerve schwannomas (P&amp;lt;0.001). Conclusion: CT and MRI with ADCs had the potential to improve the diagnostic accuracy of chondrosarcoma in the mastoid involving the facial nerve. other: none

Background The assessment of histologic grade plays an important part in prognosis evaluation of squamous cell carcinoma (SCC) of the tongue and mouth floor (MF). This study was performed to ascertain if apparent diffusion coefficient (ADC)-based radiomics can predict histologic grade in SCC of the tongue and MF. Methods This study involved 95 patients (training cohort: n = 63; testing cohort: n = 32), who were categorized as low- and high-grade SCCs according to the pathologic findings. A total of 526 radiomics features were extracted from ADC maps. Radiomics signature was constructed with least absolute shrinkage and selection operator (LASSO) logistic regression. Receiver operating characteristic curve and area under the curve (AUC) were used to evaluate the performance of the radiomic signature in the training and testing cohorts. Results Six features were selected to construct the radiomics signature for predicting histologic grade. The ADC-based radiomics signature performed well in discriminating between low- and high-grade tumors, with AUCs of 0.82 and 0.78 in the training and testing cohorts, respectively. Based on the cutoff value of the training cohort, the radiomics signature achieved accuracies of 0.75 and 0.78, sensitivities of 0.71 and 0.86, and specificities of 0.83 and 0.64 in the training and testing cohorts, respectively. Conclusions The ADC-based radiomics signature could identify histologic grade in SCC of the tongue and MF.