Apparent Diffusion Coefficient Map-Based Texture Analysis for the Differentiation of Chromophobe Renal Cell Carcinoma from Renal Oncocytoma.

Preoperative imaging differentiation between ChRCC and RO is difficult with conventional subjective evaluation, and the development of quantitative analysis is a clinical challenge. Forty-nine patients underwent partial or radical nephrectomy preceded by MRI and followed by pathological diagnosis with ChRCC or RO (ChRCC: n = 41, RO: n = 8). The whole-lesion volume of interest was set on apparent diffusion coefficient (ADC) maps of 1.5T-MRI. The importance of selected texture features (TFs) was evaluated, and diagnostic models were created using random forest (RF) analysis. The Mean Decrease Gini as calculated through RF analysis was the highest for mean_ADC_value. ChRCC had a significantly lower mean_ADC_value than RO (1.26 vs. 1.79 × 10−3 mm2/s, p < 0.0001). Feature selection by the Boruta method identified the first-quartile ADC value and GLZLM_HGZE as important features. ROC curve analysis showed that there was no significant difference in the classification performances between the mean_ADC_value-only model and the Boruta model (AUC: 0.954 vs. 0.969, p = 0.236). The mean ADC value had good predictive ability for the distinction between ChRCC and RO, comparable to that of the combination of TFs optimized for the evaluated cohort. The mean ADC value may be useful in distinguishing between ChRCC and RO.

Utility of radiomics features of diffusion-weighted magnetic resonance imaging for differentiation of fat-poor angiomyolipoma from clear cell renal cell carcinoma: model development and external validation.

PURPOSE: To investigate the utility of radiomics features of diffusion-weighted magnetic resonance imaging (DW-MRI) to differentiate fat-poor angiomyolipoma (fpAML) from clear cell renal cell carcinoma (ccRCC). MATERIALS AND METHODS: This multi-institutional study included two cohorts with pathologically confirmed renal tumors: 65 patients with ccRCC and 18 with fpAML in the model development cohort, and 17 with ccRCC and 13 with fpAML in the external validation cohort. All patients underwent magnetic resonance imaging (MRI) including DW-MRI. Radiomics analysis was used to extract 39 imaging features from the apparent diffusion coefficient (ADC) map. The radiomics features were analyzed with unsupervised hierarchical cluster analysis. A random forest (RF) model was used to identify radiomics features important for differentiating fpAML from ccRCC in the development cohort. The diagnostic performance of the RF model was evaluated in the development and validation cohorts. RESULTS: The cases in the developmental cohort were classified into three groups with different frequencies of fpAML by cluster analysis of radiomics features. RF analysis of the development cohort showed that the mean ADC value was important for differentiating fpAML from ccRCC, as well as higher-texture features including gray-level run length matrix (GLRLM)_long-run low gray-level enhancement (LRLGE), and GLRLM_low gray-level run emphasis (LGRE). The area under the curve values of the development [0.90, 95% confidence interval (CI) 0.80-1.00] and validation cohorts (0.87, 95% CI 0.74-1.00) were similar (P = 0.91). CONCLUSION: The radiomics features of ADC maps are useful for differentiating fpAML from ccRCC.

Usefulness of texture features of apparent diffusion coefficient maps in predicting chemoradiotherapy response in muscle-invasive bladder cancer.

OBJECTIVES: To examine the usefulness of the texture analysis (TA) of apparent diffusion coefficient (ADC) maps in predicting the chemoradiotherapy (CRT) response of muscle-invasive bladder cancer (MIBC). METHODS: We reviewed 45 MIBC patients who underwent cystectomy after CRT. CRT response was assessed through histologic evaluation of cystectomy specimens. Two radiologists determined the volume of interest for the index lesions on ADC maps of pretherapeutic 1.5-T MRI and performed TA using the LIFEx software. Forty-six texture features (TFs) were selected based on their contribution to the prediction of CRT sensitivity. To evaluate diagnostic performance, diagnostic models from the selected TFs were created using random forest (RF) and support vector machine (SVM), respectively. RESULTS: Twenty-three patients achieved pathologic complete response (pCR) to CRT. The feature selection identified first quartile ADC (Q1 ADC), gray-level co-occurrence matrix (GLCM) correlation, and GLCM homogeneity as important in predicting CRT response. Patients who achieved pCR showed significantly lower Q1 ADC and GLCM correlation values (0.66 × 10-3 mm2/s and 0.53, respectively) than those who did not (0.81 × 10-3 mm2/s and 0.70, respectively; p < 0.05 for both). The AUCs of the RF and SVM models incorporating the selected TFs were 0.82 (95% confidence interval [CI]: 0.67-0.97) and 0.96 (95% CI: 0.91-1.00), respectively, and the AUC of the SVM model was better than that of the mean ADC value (0.76, 95% CI: 0.61-0.90; p = 0.0037). CONCLUSION: TFs can serve as imaging biomarkers in MIBC patients for predicting CRT sensitivity. TAs of ADC maps can potentially optimize patient selection for CRT. KEY POINTS: • Texture analysis of ADC maps and feature selection identified important texture features for classifying pathologic tumor response in patients with muscle-invasive bladder cancer. • The machine learning model incorporating the texture features set, which included first quartile ADC, GLCM correlation, and GLCM homogeneity, showed high performance in predicting chemoradiotherapy response. • Texture features could serve as imaging biomarkers that optimize eligible patient selection for chemoradiotherapy in muscle-invasive bladder cancer.

Genuine- and induced-oligometastatic castration-resistant prostate cancer: clinical features and clinical outcomes after progressive site-directed therapy.

PURPOSE: To evaluate the clinical characteristics of genuine- and induced-oligometastatic castration-resistant prostate cancer (OM-CRPC) and assess the therapeutic effect of progressive-site directed therapy (PSDT). METHODS: We performed a retrospective analysis of 45 patients with OM-CRPC. Whole-body diffusion-weighted MRI (WB-DWI) was used to diagnose oligo-progressive disease. Based on the clinical and radiological findings, the OM-CRPCs were classified as genuine or induced. PSDT was performed with the intent to ablate all the progressive sites detected on WB-DWI with radiotherapy. Systemic therapy remained unchanged during and after PSDT. RESULTS: A total of 31 (69%) and 14 (31%) patients were diagnosed with genuine- and induced-OM-CRPC, respectively. The genuine-OM-CRPC group had significantly fewer patients treated with taxane-based chemotherapy and new hormonal drugs than the induced-OM-CRPC group. Of these, 26 OM-CRPC patients were treated with PSDT, and a 50% PSA decline was observed in 14 (93%) of 15 patients with genuine-OM-CRPC and 4 (36%) of 11 patients with induced-OM-CRPC (P = 0.033). Further, the duration of PSA-progression-free survival was significantly longer in the genuine-OM-CRPC group than in the induced-OM-CRPC group (8.7 vs. 5.8 months, P = 0.040). CONCLUSIONS: PSDT can be a promising treatment option for genuine-OM-CRPC. The procedure might also be considered effective for induced-OM-CRPC, although there was less therapeutic benefit of PSDT in patients with induced-OM-CRPC than in patients with genuine-OM-CRPC.

Uterine Cervical Carcinoma: Evaluation Using Non-Gaussian Diffusion Kurtosis Imaging and Its Correlation With Histopathological Findings.

OBJECTIVE: The aim of the study was to assess non-Gaussian diffusion kurtosis imaging (DKI)'s usefulness as a noninvasive method to evaluate tumor invasion depth, histological grade, and lymph node metastasis in cervical carcinoma (CC) patients. METHODS: Twenty-two consecutive patients with histologically confirmed CC were examined by 1.5-T MRI and non-Gaussian DKI with 4 b values of 0, 500, 1000, and 2000 s/mm2. Kurtosis (K), diffusivity (D), and apparent diffusion coefficient (ADC) maps were compared with histopathological findings. RESULTS: Kurtosis maps revealed the fibrous stroma as a distinct high K zone (1.442 ± 0.373) that was significantly different from values of the cervical mucosa, outer stroma, and parametrium (0.648 ± 0.083, 0.715 ± 0.113, and 0.504 ± 0.060, respectively, P < 0.0001). Kurtosis (1.189 ± 0.228) and D (0.961 ± 0.198 × 10-3 mm2/s) values of all CCs were significantly different from those of all uterine cervical wall layers. Kurtosis and D values were significantly correlated with histological grades of CCs (r = 0.934, P < 0.0001, and r = -0.925, P < 0.0001, respectively), whereas no significant differences were found in ADC values between grades 2 and 3 CCs (P = 0.787). Metastatic and nonmetastatic lymph nodes showed significantly different K (P < 0.0001) and D (P < 0.0001) values; however, their ADC values did not show significant differences (P = 0.437). For differentiating grade 3 CCs from grade 1 or 2 CCs, the areas under the curve for K (0.991, P = 0.0375) and D (0.982, P = 0.0337) values were significantly higher than those for ADC values (0.759). For differentiating metastatic and nonmetastatic lymph nodes, the areas under the curve for K (0.974, P = 0.0028) and D (0.968, P = 0.0018) values were significantly higher than those for ADC (0.596). CONCLUSIONS: Non-Gaussian DKI may be clinically useful for noninvasive evaluation of tumor invasion depth, histological grade, and lymph node metastasis in CC patients.

Diffusion tensor imaging of oral carcinoma: Clinical evaluation and comparison with histopathological findings.

PURPOSE: This study aims to assess the usefulness of diffusion tensor imaging (DTI) as a noninvasive method for the evaluation of histological grade and lymph node metastasis in patients with oral carcinoma (OC). MATERIALS AND METHODS: Thirty-six consecutive patients with histologically confirmed OC underwent examination by 3-T MRI. DTI was performed using a single-shot echo-planar imaging sequence with b values of 0 and 1000 s/mm2 and motion-probing gradients in 12 noncollinear directions. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) maps were compared with histopathological findings. The DTI parameters were correlated with the histological grade of the OCs based on the World Health Organization grading criteria and the presence or absence of lymph node metastasis. RESULTS: The FA values (0.275 ± 0.058) of OC were significantly lower than those of normal tongue, muscle, and parotid glands (P < 0.001 for all), and the MD, AD, and RD values (1.220 ± 0.149, 1.434 ± 0.172, and 1.019 ± 0.165 × 10-3 mm2/s, respectively) were significantly higher than their respective normal values (P < 0.001 for all). Significant inverse correlations with histological grades were shown for FA, MD, AD, and RD values in OC patients (r = -0.862, r = -0.797, r = -0.747, and r = -0.844, respectively; P < 0.001 for all). In addition, there was a significant difference in the FA values of metastatic and nonmetastatic lymph nodes (0.186 vs. 0.276), MD (0.923 vs. 1.242 × 10-3 mm2/s), AD (1.246 vs. 1.621 × 10-3 mm2/s), and RD (0.792 vs. 1.100 × 10-3 mm2/s; P < 0.001 for all). CONCLUSIONS: DTI may be clinically useful for the noninvasive evaluation of histological grade and lymph node metastasis in OC patients.

Diffusion tensor imaging of rectal carcinoma: Clinical evaluation and its correlation with histopathological findings.

OBJECTIVE: This study sought to assess the feasibility of diffusion tensor imaging (DTI) to noninvasively evaluate histological grade and lymph node metastasis in patients with rectal carcinoma (RC). METHODS: Thirty-seven consecutive patients with histologically confirmed RC were examined by 1.5-T MRI. DTI was performed using a single-shot echo-planar imaging sequence with b values of 0 and 1000 s/mm2 and motion-probing gradients in nine noncollinear directions. Fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) maps were compared with histopathological findings. RESULTS: The FA values (0.357 ±â€¯0.047) of the RCs were significantly lower than those of the normal rectal wall, muscle, prostate, and uterus (P < 0.001 for all), while the AD, MD, and RD values (1.221 ±â€¯0.131, 0.804 ±â€¯0.075, and 0.667 ±â€¯0.057 × 10-3 mm2/s, respectively) were also significantly lower than their respective normal values (P < 0.001 for all). The FA, AD, MD, and RD values for RC additionally showed significant inverse correlations with histological grades (r = -0.781, r = -0.750, r = -0.718, and r = -0.682, respectively; P < 0.001 for all). Further, the FA (0.430 vs. 0.611), AD (1.246 vs. 1.608 × 10-3 mm2/s), MD (0.776 vs. 1.036 × 10-3 mm2/s), and RD (0.651 vs. 0.824 × 10-3 mm2/s) (P < 0.001 for all) of the metastatic and nonmetastatic lymph nodes were significantly different. CONCLUSIONS: DTI may be clinically useful for the noninvasive evaluation of histological grade and lymph node metastasis in patients with RC.

Diffusion-Tensor Imaging of Uterine Cervical Carcinoma: Correlation With Histopathologic Findings.

The authors investigated the usefulness of diffusion-tensor imaging (DTI) for evaluating tumor invasion depth, histologic grade, and lymph node metastasis in patients with cervical carcinoma (CC). Fifteen consecutive patients with histologically confirmed CC underwent 1.5-T magnetic resonance imaging and DTI. The CCs were clearly depicted as hypointense areas on all DTI maps. Fractional anisotropy, mean diffusivity, and axial diffusivity showed significantly inverse correlations with CC histologic grades and were significantly different between metastatic and nonmetastatic lymph nodes.

Texture Analysis of Apparent Diffusion Coefficient Maps in Cervical Carcinoma: Correlation with Histopathologic Findings and Prognosis.

Purpose: To determine the feasibility of texture analysis of apparent diffusion coefficient (ADC) maps and to assess the performance of texture analysis and ADC to predict histologic grade, parametrial invasion, lymph node metastasis, International Federation of Gynecology and Obstetrics (FIGO) stage, recurrence, and recurrence-free survival (RFS) in patients with cervical carcinoma. Materials and Methods: This retrospective study included 58 patients with cervical carcinoma who were examined with a 1.5-T MRI system and diffusion-weighted imaging with b values of 0 and 1000 sec/mm2. Software with volumes of interest on ADC maps was used to extract 45 texture features, including higher-order texture features. Receiver operating characteristic (ROC) analysis was performed to compare the diagnostic performance of ADC map random forest models and of ADC values. Dunnett test, Spearman rank correlation coefficient, Kaplan-Meier analyses, log-rank test, and Cox proportional hazards regression analyses were also used for statistical analyses. Results: The ADC map random forest models showed a significantly larger area under the ROC curve (AUC) than the AUC of ADC values for predicting high-grade cervical carcinoma (P = .0036), but not for parametrial invasion, lymph node metastasis, stages III-IV, and recurrence (P = .0602, .3176, .0924, and .5633, respectively). The random forest models predicted that the mean RFS rates were significantly shorter for high-grade cervical carcinomas, parametrial invasion, lymph node metastasis, stages III-IV, and recurrence (P = .0405, < .0001, .0344, .0001, and .0015, respectively); the random forest models for parametrial invasion and stages III-IV were more useful than ADC values (P = .0018) for predicting RFS. Conclusion: The ADC map random forest models were more useful for noninvasively evaluating histologic grade, parametrial invasion, lymph node metastasis, FIGO stage, and recurrence and for predicting RFS in patients with cervical carcinoma than were ADC values.Keywords: Comparative Studies, Genital/Reproductive, MR-Diffusion Weighted Imaging, MR-Imaging, Neoplasms-Primary, Pathology, Pelvis, Tissue Characterization, UterusSupplemental material is available for this article.© RSNA, 2020See also the commentary by Reinhold and Nougaret in this issue.

Diffusion kurtosis imaging of endometrial carcinoma: Correlation with histopathological findings.

PURPOSE: In this study, we aimed to determine the usefulness of diffusion kurtosis imaging (DKI) as a noninvasive method for the evaluation of tumor invasion depth, histological grade, and lymph node metastasis in patients with endometrial carcinoma (EMC). MATERIALS AND METHODS: Our institutional review board approved this retrospective study and waived informed consent. In total, 24 patients suspected of having EMC were examined by a 1.5-T magnetic resonance imaging. DKI data were obtained using a single-shot echo-planar imaging sequence with four b values (0, 500, 1000, and 2000 s/mm2). Kurtosis (K), diffusivity (D), and apparent diffusion coefficient (ADC) maps were generated and compared with histopathological findings. RESULTS: K maps from all patients identified the junctional zone as a distinct high-K zone (1.443 ±â€¯0.362). This zone was significantly different from the zone of endometrium and outer myometrium (0.678 ±â€¯0.179 and 0.694 ±â€¯0.113, respectively; P < 0.001). K and D values of all EMCs were significantly different from those of all normal uterine wall layers. K and D values were significantly correlated with histological grades of endometrioid adenocarcinomas (r = 0.799, P < 0.001 and r = -0.799, P < 0.001, respectively), while ADC values were not (r = -0.243, P = 0.382). Metastatic and nonmetastatic lymph nodes showed significantly different K (P = 0.001) and D (P = 0.001) values, but not ADC values (P = 0.827). CONCLUSIONS: DKI may be clinically useful for the noninvasive evaluation of depth of tumor invasion, histological grade, and lymph node metastasis in patients with EMC.

Endometrial Carcinoma: Texture Analysis of Apparent Diffusion Coefficient Maps and Its Correlation with Histopathologic Findings and Prognosis.

Purpose: To determine the feasibility of texture analysis (TA) of apparent diffusion coefficient (ADC) maps for predicting histologic grade (HG) and recurrence-free survival (RFS) in patients with endometrial carcinoma (EMC). Materials and Methods: One hundred twenty-one patients with EMC were examined by using a 1.5-T MRI system and diffusion-weighted imaging (DWI) with b values of 0 and 1000 sec/mm2. Software with volumes of interest on ADC maps was used to extract 45 texture features including higher-order texture features. Receiver operating characteristic analysis was performed to compare the diagnostic performance of the random forest (RF) model and ADC values for HG and recurrence. Results: Area under the curve (AUC) for predicting high-grade EMCs was significantly larger for RF model than for ADC values (0.967 vs 0.898; P = .0336). AUC for predicting recurrence was larger for the RF model than for ADC values (0.890 vs 0.875; P = .7248), although the difference was not significant. Mean RFS was significantly shorter for high-grade EMCs than for low-grade EMCs (P = .0002; hazard ratio, 4.9) and for ADC values less than or equal to 0.802 × 10-3 mm2/sec than for ADC values greater than 0.802 × 10-3 mm2/sec (P < .0001; hazard ratio, 32.9). RF model showed that the mean RFS was significantly shorter for the presence of recurrence than for its absence (P < .0001; hazard ratio, 94.7). Conclusion: TA of ADC maps had significantly higher diagnostic performance than did ADC values for predicting HG and was a more useful indicator than HG and ADC values for predicting RFS in patients with EMC.Keywords: Comparative Studies, Genital/Reproductive, MR-Diffusion Weighted Imaging, MR-Imaging, Neoplasms-Primary, Pathology, Pelvis, Tissue Characterization, Uterus© RSNA, 2019.

Endometrial carcinoma: Evaluation using diffusion-tensor imaging and its correlation with histopathologic findings.

BACKGROUND: Although the prognosis of endometrial carcinoma (EMC) patients strictly depends on tumor invasion depth and its histologic grade, accurate preoperative assessment of these prognostic factors is often difficult. PURPOSE: To determine the usefulness of diffusion-tensor imaging (DTI) as a noninvasive method for evaluating tumor invasion depth and its histologic grade in patients with EMC. STUDY TYPE: Prospective. POPULATION: Twenty-five consecutive patients with histologically confirmed EMC who were surgically treated at our institution. FIELD STRENGTH/SEQUENCE: DTI was performed with a 1.5T MRI system using a single-shot echo-planar imaging sequence with b values of 0 and 1000 s/mm2 and motion-probing gradients in nine noncollinear directions. ASSESSMENT: Fractional anisotropy (FA), mean diffusivity (MD), and axial diffusivity (AD) maps were analyzed by three observers and compared with histopathologic findings. STATISTICAL TESTS: Dunnett's test, Spearman's rank correlation coefficient, and receiver operating characteristic (ROC) curve analyses. RESULTS: FA maps from all patients distinctly identified the junctional zone as a high-FA zone (0.864 ± 0.037) that was significantly different from the endometrium and outer myometrium (0.251 ± 0.030 and 0.471 ± 0.091, respectively; P < 0.001). All EMCs were clearly depicted as hypointense areas on all DTI maps. AD maps provided the best tumor-to-uterus contrast, and EMCs (0.977 ± 0.120 × 10-3 mm2 /s) had significantly lower AD values than all other layers of the normal uterine wall (2.166 ± 0.408, 2.010 ± 0.289, and 2.655 ± 0.203 × 10-3 mm2 /s, respectively; P < 0.001). EMCs were clearly demarcated from the normal uterine wall, and DTI maps and histopathologic data yielded identical findings regarding tumor invasion depth. FA values showed a significant inverse correlation (r = -0.818; P < 0.001) with histologic grades 1, 2, and 3 of endometrioid adenocarcinomas. DATA CONCLUSION: In patients with EMC, DTI may be useful for evaluating tumor invasion depth and its histologic grade. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:250-260.

Community response to a step change in the aircraft noise exposure around Hanoi Noi Bai International Airport.

In December 2014, a new terminal building was opened at the Hanoi Noi Bai International Airport (HNBIA) with two runways, causing a 20%-30% increase in the number of flights. Three socio-acoustic surveys were conducted in August-September 2014, February-March 2015, and August-September 2015, to contribute not only to the environmental impact assessments and aircraft noise policies in Vietnam but also to more global intervention studies. Because of the change of runway use, in addition to the increased number of flights, noise exposure at each site changed considerably among the surveys. Changes in the noise exposure from the first to the second or third survey (ΔLden and ΔLnight) were used as a measure of exposure change. Multiple logistic regression analysis showed that ΔLden has a significant positive effect on annoyance regardless of ΔLden ranges, but the effect of ΔLnight on insomnia was significant only for ΔLnight > 0. Annoyance increase in the overall ΔLden range may be caused by the respondents' recognition of increase in emission in addition to practical increase in exposure. More severe attitudes to airplanes around HNBIA might increase annoyance even if noise exposure decreases. Thus, the change effect clearly occurs in annoyance but partially in insomnia.

Oral carcinoma: Clinical evaluation using diffusion kurtosis imaging and its correlation with histopathologic findings.

PURPOSE: In this study, we aimed to determine the usefulness of diffusion kurtosis imaging (DKI) as a noninvasive method for evaluation of the histologic grade and lymph node metastasis in patients with oral carcinoma. MATERIALS AND METHODS: Twenty-seven patients with oral carcinoma were examined with a 3-T MR system and 16-channel coil. DKI data were obtained by a single-shot echo-planar imaging sequence with repetition time, 10,000 ms; echo time, 94 ms; field of view, 250 × 204.25 ms; matrix, 120 × 98; section thickness, 4 mm; four b values of 0, 500, 1000, and 2000 s/mm2; and motion-probing gradients in three orthogonal directions. Diffusivity (D) and kurtosis (K) were calculated using the equation: S = S0 ∙ exp(-b ∙ D + b2 ∙ D2 ∙ K/6). Conventional apparent diffusion coefficient (ADC) was also calculated. The MR images were compared with the histopathologic findings. RESULTS: Relative to the histologic grades (Grades 1, 2, and 3) of the 27 oral carcinomas, D values showed a significant inverse correlation (r = -0.885; P < 0.001) and K values showed a significant positive correlation (r = 0.869; P < 0.001), whereas ADC values showed no significant correlation (r = -0.311; P = 0.115). When comparing between metastatic and non-metastatic lymph nodes, significant differences in the D values (P < 0.001) and K values (P < 0.001), but not the ADC values (P = 0.110) became apparent. CONCLUSIONS: In patients with oral carcinoma, DKI seems to be clinically useful for the evaluation of histologic grades and lymph node metastasis.

Colorectal carcinoma: Ex vivo evaluation using q-space imaging; Correlation with histopathologic findings.

BACKGROUND: Although the prognosis of colorectal carcinoma (CRC) patients depends on the histologic grade (HG) and lymph node metastasis (LNM), accurate preoperative assessment of these prognostic factors is often difficult. PURPOSE: To assess the HG and extent of LNM by q-space imaging (QSI) for preoperative diagnosis of CRC. STUDY TYPE: Prospective. SPECIMEN: A total of 20 colorectal tissue samples containing adenocarcinomas and resected lymph nodes (LNs). FIELD STRENGTH/SEQUENCE: QSI was performed with a 3T MRI system using a diffusion-weighted echo-planar imaging sequence: repetition time, 10,000 msec; echo time, 216 or 210 msec; field of view, 113 × 73.45 mm; matrix, 120 × 78; section thickness, 4 mm; and 11 b values ranging from 0 to 9000 s/mm2 . ASSESSMENT: The mean displacement (MDP; µm), zero-displacement probability (ZDP; arbitrary unit [a.u.]), kurtosis (K; a.u.), and apparent diffusion coefficient (ADC) were analyzed by two observers and compared with histopathologic findings. STATISTICAL TESTS: Spearman's rank correlation coefficient, Mann-Whitney U-test, and ROC curve analyses. RESULTS: For all 20 carcinomas, the MDP, ZDP, K, and ADC were 8.87 ± 0.37 µm, 82.0 ± 6.2 a.u., 74.3 ± 3.0 a.u., and 0.219 ± 0.040 × 10-3 mm2 /s, respectively. The MDP (r = -0.768; P < 0.001), ZDP (r = 0.768; P < 0.001), and K (r = 0.785; P < 0.001) were significantly correlated with the HG of CRC, but not the ADC (r = 0.088; P = 0.712). There were also significant differences in the MDP, ZDP, and K between metastatic and nonmetastatic LNs (all, P < 0.001), but not the ADC (P = 0.082). In the HG of CRC and LNM, the area under the curve was significantly greater for MDP, ZDP, and K than for ADC. DATA CONCLUSION: QSI provides useful diagnostic information to assess the HG and extent of LNM in CRC. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1059-1068.

Pitfalls in the diagnosis of pupil-sparing oculomotor nerve palsy without limb ataxia: A case report of a variant of Claude's syndrome and neuroanatomical analysis using diffusion-tensor imaging.

Midbrain infarction causing oculomotor nerve palsy with contralateral ataxia is named Claude's syndrome. Herein we report the case of a variant of Claude's syndrome, which shows pupil-sparing oculomotor nerve palsy without the accompanying neurological deficits other than subtle truncal ataxia. MRI and Diffusion Tensor Imaging revealed that midbrain infarction was located rostrally above the decussation of the superior cerebellar peduncle (SCP) and might have partially destructed the tectospinal tract, which resulted in the absence of limb ataxia and presence of subtle truncal ataxia. In this variant of Claude's syndrome, we should carefully assess truncal ataxia to avoid misdiagnosing it as isolated pupil-sparing oculomotor nerve palsy because the patient showed apparently normal gait and truncal ataxia was only revealed by unstable tandem gait.

Colorectal carcinoma: Ex vivo evaluation using 3-T high-spatial-resolution quantitative T2 mapping and its correlation with histopathologic findings.

PURPOSE: In this study, we aimed to evaluate the feasibility of determining the mural invasion depths of colorectal carcinomas using high-spatial-resolution (HSR) quantitative T2 mapping on a 3-T magnetic resonance (MR) scanner. MATERIALS AND METHODS: Twenty colorectal specimens containing adenocarcinomas were imaged on a 3-T MR system equipped with a 4-channel phased-array surface coil. HSR quantitative T2 maps were acquired using a spin-echo sequence with a repetition time/echo time of 7650/22.6-361.6ms (16 echoes), 87×43.5-mm field of view, 2-mm section thickness, 448×224 matrix, and average of 1. HSR fast-spin-echo T2-weighted images were also acquired. Differences between the T2 values (ms) of the tumor tissue, colorectal wall layers, and fibrosis were measured, and the MR images and histopathologic findings were compared. RESULTS: In all specimens (20/20, 100%), the HSR quantitative T2 maps clearly depicted an 8-layer normal colorectal wall in which the T2 values of each layer differed from those of the adjacent layer(s) (P<0.001). Using this technique, fibrosis (73.6±9.4ms) and tumor tissue (104.2±6.4ms) could also be clearly differentiated (P<0.001). In 19 samples (95%), the HSR quantitative T2 maps and histopathologic data yielded the same findings regarding the tumor invasion depth. CONCLUSIONS: Our results indicate that 3-T HSR quantitative T2 mapping is useful for distinguishing colorectal wall layers and differentiating tumor and fibrotic tissues. Accordingly, this technique could be used to determine mural invasion by colorectal carcinomas with a high level of accuracy.

Gastric carcinoma: Evaluation with diffusion-tensor MR imaging and tractography ex vivo.

PURPOSE: To determine the feasibility of diffusion-tensor imaging (DTI) and tractography as means of evaluating the depth of mural invasion by gastric carcinomas. MATERIALS AND METHODS: This study was approved by our institutional review board, and written informed consent was obtained from each patient. Twenty gastric specimens containing a carcinoma were studied with a 7.0-T MR imaging system equipped with a four-channel phased-array surface coil. DTI was performed by using a field of view of 50-60 mm × 25-30 mm, matrix of 256 × 128, section thickness of 1mm, b value of 1000 s/mm2, and motion-probing gradients in seven noncollinear directions. The MR images were compared with the histopathologic findings as the reference standard. RESULTS: In all 20 carcinomas (100%) the diffusion-weighted images, apparent diffusion coefficient (ADC) maps, fractional anisotropy (FA) maps, λ1 maps, and direction-encoded color FA maps made it possible to identify the same depth of tumor invasion of the gastric wall as observed during histopathologic examination. The λ1 maps provided the best contrast between the carcinomas and the layers of the gastric wall. The carcinomas also had lower ADC values and lower FA values than the normal gastric wall; thus, the carcinomas were clearly demarcated from the normal gastric wall. Tractography images were also useful for determining the depth of tumor invasion of the gastric wall. CONCLUSIONS: DTI and tractography are feasible means of evaluating gastric specimens and provide excellent diagnostic accuracy for evaluating mural invasion by gastric carcinomas.

q-space MR imaging of gastric carcinoma ex vivo: Correlation with histopathologic findings.

PURPOSE: The purpose of this study was to establish the feasibility of q-space imaging (QSI) as a method of assessing the depth of mural invasion, histologic grade, and the presence of lymph node metastasis in gastric carcinomas. METHODS: A 7.0 Tesla MR imaging system was used to investigate 20 gastric specimens containing a carcinoma. QSI was performed by using the following parameters: 50-60 mm × 25-30 mm field of view, 2-mm section thickness, 256 × 128 matrix, 10 b values in the 0-7163 s/mm(2) range, which corresponded to q values of 0-1026/cm, and motion-probing gradients perpendicular to the gastric wall. The MR images and the histopathologic findings were then compared. RESULTS: The depth of tumor invasion of the gastric wall in all 20 carcinomas (100%) was established by using mean displacement, zero-displacement probability, and kurtosis maps. The QSI parameters were significantly correlated with the histologic grades of the gastric carcinomas (all P < 0.001). The QSI parameters made it possible to differentiate between metastatic and nonmetastatic lymph nodes (all P = 0.001). CONCLUSION: Ex vivo QSI facilitates excellent diagnostics for evaluating gastric carcinomas in terms of mural invasion, histologic grade, and the presence of lymph node metastasis. Magn Reson Med 76:602-612, 2016. © 2015 Wiley Periodicals, Inc.