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Purpose: To analyze and compare the differences in MRI features between combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CCA) and intrahepatic cholangiocarcinoma (iCCA) with arterial phase peripheral enhancement, so as to provide valuable references for preoperative differential diagnosis., Methods: Seventy cHCC-CCA patients and 74 iCCA patients confirmed by pathology were included in this study. Their contrast-enhanced MRI showed rim arterial phase hyperenhancement (Rim APHE). The differences of clinicopathological data and MRI features between cHCC-CCA and iCCA were compared. Then, the sensitivity, specificity, and area under curve (AUC) were also analyzed and compared., Results: Seventy cHCC-CCA patients (mean age, 55.7 ± 10.6 years) and 74 iCCA patients (mean age, 61.1 ± 10.5 years) were evaluated. In this study, univariable and multivariable regression analysis showed that AFP > 20 ng/ml (OR = 5.824, p = 0.006), enhancing capsule (OR = 7.252, p = 0.001), and mosaic architecture (OR = 32.732, p < 0.001) were independent risk factors of cHCC-CCA with Rim APHE. However, only hepatic capsule retraction (OR = 0.091, p < 0.001) was an independent predictor of iCCA. In addition, combining AFP > 20 ng/ml with enhancing capsule (96.7% vs. 79.2%, p < 0.001) and/or mosaic architecture (96.4% vs. 94.7%, p < 0.001) can improve the sensitivity of differentiating cHCC-CCA (vs. iCCA) with Rim APHE., Conclusion: The combination of elevated AFP and MRI features, such as enhancing capsule and mosaic architecture, will help in preoperative differential diagnosis of cHCC-CCA and iCCA with Rim APHE., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: To explore which preoperative clinical data and conventional magnetic resonance imaging (MRI) features may indicate the presence of hepatocellular carcinoma (HCC) in HCC patients coexisting with LR-3 and LR-4 lesions., Methods: HCC Patients coexisting with LR-3 and LR-4 lesions who participated in a prospective clinical trial (XX) were included in this study. Two radiologists independently assessed the preoperative MRI features and each lesion was assigned according to the liver imaging reporting and data system (LI-RADS). The preoperative clinical data were also evaluated. The relative values of these parameters were assessed as potential predictors of HCC for coexisting LR-3 and LR-4 lesions., Results: We enrolled 102 HCC patients (58.1 ± 11.5 years; 84.3% males) coexisting with 110 LR-3 and LR-4 lesions (HCCs group [n = 66]; non-HCCs group [n = 44]). The presence of restricted diffusion (OR: 18.590, p < 0.001), delayed enhancement (OR: 0.113, p < 0.001), and mild-moderate T2 hyperintensity (OR: 3.084, p = 0.048) were found to be independent predictors of HCC diagnosis. The sensitivity and specificity of the above independent variables for the diagnosis of HCC ranged from 66.7 to 80.3% and 56.8 to 88.6%, respectively. ROC analysis showed that, in discriminating HCC, the AUCs of the above factors were 0.777, 0.686, and 0.670, respectively. Combining these three findings for the prediction of HCC resulted in a specificity greater than 97%, and the AUC further increased to 0.874., Conclusion: The presence of restricted diffusion, delayed enhancement, and mild-moderate T2 hyperintensity can be useful features for risk stratification of coexisting LR-3 and LR-4 lesions in HCC patients. Trial registration a prospective clinical trial (ChiCTR2000036201)., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Context: Dysthyroid optic neuropathy (DON) is a serious vision-threatening complication of thyroid-associated ophthalmopathy (TAO). Exploration of the underlying mechanisms of DON is critical for its timely clinical diagnosis., Objective: We hypothesized that TAO patients with DON may have altered brain functional networks. We aimed to explore the alterations of static and dynamic functional connectomes in patients with and without DON using resting-state functional magnetic resonance imaging with the graph theory method., Methods: A cross-sectional study was conducted at a grade A tertiary hospital with 66 TAO patients (28 DON and 38 non-DON) and 30 healthy controls (HCs). Main outcome measures included topological properties of functional networks., Results: For static properties, DON patients exhibited lower global efficiency (Eg), local efficiency, normalized clustering coefficient, small-worldness (σ), and higher characteristic path length (Lp) than HCs. DON and non-DON patients both exhibited varying degrees of abnormalities in nodal properties. Meanwhile, compared with non-DON, DON patients exhibited abnormalities in nodal properties in the orbitofrontal cortex and visual network (VN). For dynamic properties, the DON group exhibited higher variance in Eg and Lp than non-DON and HC groups. A strengthened subnetwork with VN as the core was identified in the DON cohort. Significant correlations were found between network properties and clinical variables. For distinguishing DON, the combination of static and dynamic network properties exhibited optimal diagnostic performance., Conclusion: Functional network alterations were observed both in DON and non-DON patients, providing novel insights into the underlying neural mechanisms of disease. Functional network properties may be potential biomarkers for reflecting the progression of TAO from non-DON to DON., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Patients with comitant exotropia (CE) would usually develop compromised binocular vision and impaired stereoscopic depth perception, which could result in a profound decrease in quality of life. Although the deviated optic axis could be corrected surgically, the impaired stereovision and sensory eye balance may sometimes remain remnant. This study was to investigate the brain functional alterations in patients with CE before and after surgery, using resting-state functional magnetic resonance imaging (fMRI) with amplitude of low-frequency fluctuation (ALFF). Thirty-five patients with CE were recruited to undergo a preoperative fMRI scan, as well as 24 healthy controls (HCs). Twenty-four of the patients were available for rescanned fMRI one month after surgery. The ALFF method was used to evaluate the group differences of spontaneous brain activity. The correlations between ALFF values and clinical variables were analyzed in the patient group. Preoperatively, compared with HCs, 35 patients with CE showed significantly decreased ALFF values in one cluster involving bilateral calcarine sulcus, lingual gyrus and cuneus. The ALFF values in the above cluster were negatively correlated with disease duration (r = -0.379, P = 0.033). One month after surgery, 24 patients with available rescanned fMRI demonstrated increased ALFF values in one cluster located in bilateral cuneus, calcarine sulcus and lingual gyrus relative to the preoperative collection, while still reduced ALFF values in the cluster involving left calcarine sulcus and lingual gyrus compared with HCs. Our study revealed the functional changes of patients with CE in visual-associated brain areas before and after surgery. The findings may provide a new perspective for understanding the underlying pathological mechanisms of CE., Competing Interests: Declaration of competing interest The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objective: To compare and correlate the findings of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging and arterial spin labeling (ASL) imaging in characterizing parotid gland tumors., Materials and Methods: We retrospectively reviewed 56 patients with parotid gland tumors evaluated by MR imaging. The true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and fraction of perfusion (f) values of IVIM imaging and tumor-to-parotid gland signal intensity ratio (SIR) on ASL imaging were calculated. Spearman rank correlation coefficient, chi-squared, Mann-Whitney U, and Kruskal-Wallis tests with the post-hoc Dunn-Bonferroni method and receiver operating characteristic curve assessments were used for statistical analysis., Results: Malignant parotid gland tumors showed significantly lower D than benign tumors ( p = 0.019). Within subgroup analyses, pleomorphic adenomas (PAs) showed significantly higher D than malignant tumors (MTs) and Warthin's tumors (WTs) ( p < 0.001). The D* of WTs was significantly higher than that of PAs ( p = 0.031). The f and SIR on ASL imaging of WTs were significantly higher than those of MTs and PAs ( p < 0.05). Significantly positive correlation was found between SIR on ASL imaging and f ( r = 0.446, p = 0.001). In comparison with f, SIR on ASL imaging showed a higher area under curve (0.853 vs. 0.891) in discriminating MTs from WTs, although the difference was not significant ( p = 0.720)., Conclusion: IVIM and ASL imaging could help differentiate parotid gland tumors. SIR on ASL imaging showed a significantly positive correlation with f. ASL imaging might hold potential to improve the ability to discriminate MTs from WTs., Competing Interests: The authors have no potential conflicts of interest to disclose., (Copyright © 2021 The Korean Society of Radiology.)

Objective: To compare the two-point Dixon T 2 weighted imaging ( T 2 WI) with conventional fat-sat T 2 WI in fat suppression (FS) quality and staging performance for patients with TAO., Methods: We enrolled 37 thyroid-associated ophthalmopathy (TAO) patients and 15 healthy controls who underwent both coronal two-point Dixon and fat-sat T 2 WI. Qualitative (overall imaging quality, FS uniformity) and quantitative [signal intensity ratio of extraocular muscle (EOM-SIR)] parameters were assessed between the two-point Dixon T 2 WI and fat-sat T 2 WI. Additionally, water fraction of intraorbital fat (IF-WF) was measured on Dixon image. Dixon-EOM-SIR, Fat-sat-EOM-SIR and Dixon-IF-WF values were compared between active and inactive TAO groups, and the diagnostic efficiency for the active phase were evaluated., Results: Two-point Dixon T 2 WI showed significantly higher overall image quality score, FS uniformity score as well as EOM-SIR value than fat-sat T 2 WI in both TAO and control groups (all p < 0.05). Active TAOs had significantly higher Dixon-EOM-SIR ( p < 0.001), Fat-sat-EOM-SIR ( p < 0.001) and Dixon-IF-WF ( p = 0.001) than inactive TAOs. ROC curves analyses indicated that Dixon-EOM-SIR ≥3.32 alone demonstrated the highest staging sensitivity (75.0%). When integrating Dixon-EOM-SIR ≥3.32 and Dixon-IF-WF ≥0.09, improved staging efficiency and specificity could be achieved (area under the curve, 0.872; specificity, 97.1%)., Conclusion: Compared with conventional fat-sat technique, two-point Dixon T 2 WI offers better image quality, as well as improved staging sensitivity and specificity for TAO. Dixon T 2 WI is suggested to be used to evaluate the patients with TAO in clinical practice., Advances in Knowledge: Two-point Dixon T 2 WI offers better image quality than fat-sat T 2 WI. Dixon-EOM-SIR alone demonstrated the highest staging sensitivity. Combining with Dixon-IF-WF showed improved staging efficiency and specificity. Dixon T 2 WI is suggested to be used to evaluate TAO patients in clinical practice.

Background: Discriminating the stage of thyroid-associated ophthalmopathy (TAO) is crucial for the treatment strategy and prognosis prediction. Utility of conventional magnetic resonance imaging in the disease staging is limited., Purpose: To investigate the performance of T2 mapping based on different region of interest (ROI) selection methods in the staging of TAO., Material and Methods: Thirty-two patients with TAO were retrospectively enrolled. Two radiologists independently measured the T2 relaxation time (T2RT) of extraocular muscles using two different ROIs (hotspot [ROI HS ]: T2RT-hot; single-slice [ROI SS ]: T2RT-mean, T2RT-max, T2RT-min). Independent-samples t test, Wilcoxon signed rank test, Spearman correlation analysis, receiver operating characteristic (ROC) curves analyses, multiple ROC comparisons, and intra-class correlation coefficient (ICC) were used for statistical analyses., Results: No significant difference was found in the measuring time between ROI HS and ROI SS methods ( P  = 0.066). T2RT-mean demonstrated the highest ICC for measurement, followed by T2RT-max and T2RT-min, and T2RT-hot showed the poorest reproducibility. Active TAOs showed significantly higher values for all the T2RTs than inactive mimics (all P  < 0.001). Significant positive correlations were found between T2RTs and CAS (all P  < 0.005). T2RT-hot and T2RT-max showed significantly higher areas under the curve than that of T2RT-mean ( P  = 0.013 and 0.024, respectively), while the difference between T2RT-hot and T2RT-max was not significant ( P  = 0.970)., Conclusion: The T2RTs derived from both ROI selection methods could be useful for the staging of TAO. The results of measuring time, reproducibility, and diagnostic performance suggest that T2RT-max would be the optimal indicator for staging.

Background: T2-mapping technique and derived T2 relaxation time allows quantitative assessment of extraocular muscles; however, the reproducibility of T2 mapping-derived parameters was seldom studied till now., Purpose: To evaluate the scan-rescan and observer-observer reproducibility of T2 relaxation time measurements of extraocular muscles in young healthy volunteers., Material and Methods: Fourteen volunteers underwent T2-mapping examinations of the extraocular muscles three times within one month on a 3.0-T MR system. Scan-rescan and observer-observer reproducibility of T2 relaxation time measurements of the extraocular muscles were assessed using intraclass correlation coefficient and coefficient of variation., Results: Both scan-rescan (short-term and long-term) and observer-observer could achieve good to excellent reproducibility, while better short-term than long-term scan-rescan reproducibility was obtained. The coefficient of variation of the T2 relaxation time of each extraocular muscles during both scan-rescan and observer-observer reproducibility assessment were <6%., Conclusion: T2 relaxation time measurement of the extraocular muscles is proven to be highly reproducible at 3.0 T. T2 mapping may be a potential imaging technique in the diagnosis and follow-up of orbital diseases involved extraocular muscles in further studies.

Purpose: MR neurography(MRN) is an advanced imaging technique to visualize peripheral nerves. Our aim was to determine the value of morphological features of lumbosacral nerve roots on MRN in diagnosing chronic inflammatory demyelinating polyradiculoneuropathy(CIDP) and analyze their correlations with electrophysiological parameters., Methods: MRN of lumbosacral plexus was performed in 21 CIDP patients and 21 healthy volunteers. The cross-sectional areas(CSAs) and signal intensities(SI) of L3 to S1 nerve roots were measured and compared between two groups. Receiver operating characteristic(ROC) curves were plotted to assess the diagnostic accuracy. All patients also underwent nerve conduction studies. Correlations between CSAs and SI of lumbosacral nerve roots and electrophysiological parameters were analyzed., Results: Compared with control group, CIDP patients showed significantly increased CSAs and SI from L3 to S1 nerve root (P < 0.001 and P < 0.05 respectively for all nerve roots). The CSA mean and SI mean were 28.04 ± 8.55mm 2 , 1.314 ± 0.199 for patient group and 14.91 ± 2.36mm 2 ,1.155 ± 0.094 for control group. ROC analysis revealed the best diagnostic accuracy for the CSA mean with an area under the curve of 0.968 and optimal cut-off value of 19.20 mm 2 . CSAs of L5 or S1 nerve root correlated positively with central latency and negatively with conduction velocity of tibial nerve. SI of L5 also had a positive correlation with latency of sural nerve., Conclusions: Evaluation of lumbosacral nerve roots on MRN in a quantitative manner may serve as an important tool to support the diagnosis of CIDP., Competing Interests: Declaration of Competing Interest The authors have no conflicts of interest to declare., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Objectives:: To evaluate the effect of laterality, gender, age and body mass index (BMI) on fat fraction (FF) measurements of both parotid glands (PGs) and submandibular glands (SMGs) by using: Iterative decomposition of water and fat with echo asymmetry and least-squares estimation method (IDEAL-IQ)., Methods:: A total of 87 healthy participants were enrolled in our study. IDEAL-IQ image was scanned using a 3.0 T scanner. Paired t test was performed to compare the difference on FF of both PGs and SMGs between left and right side. The FF of two glands between male and female healthy participants were compared using an unpaired t-test. The correlation between the FF of two glands and participant age or BMI were analyzed by Pearson's correlation., Results:: Excellent inter- and intrareader agreements were obtained during the measurements of FF by IDEAL-IQ method (ICC, 0.952-0.981). FF values correlated positively with the age and BMI in both left and right PGs and SMGs (p < 0.05). No significant difference was found on FF between left and right PGs and SMGs (p > 0.05). There was also no difference on FF between male and female healthy participants (p > 0.05)., Conclusions:: FFs of PGs and SMGs were age- and BMI- dependent, but not laterality- and gender-dependent. The effect of age and BMI need to be considered in further studies using Ideal-IQ technology to evaluate FFs of salivary gland diseases.

To evaluate the performance of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) for differentiating orbital malignant from benign tumors, and to assess the correlation between IVIM-DWI parameters and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters.Twenty-seven patients (17 benign and 10 malignant) with orbital tumors underwent 3.0T MRI examination for pre-treatment evaluation, including IVIM-DWI and DCE-MRI. IVIM-DWI parameters (tissue diffusivity, D; pseudo-diffusion coefficient, D; and perfusion fraction, f) were quantified using bi-exponential fitting model. DCE-MRI parameters (K, the volume transfer constant between the plasma and the extracellular extravascular space [EES]; Ve, the volume fraction of the EES, and Kep, the rate constant from EES to blood plasma) were quantified using modified Tofts model. Independent-sample t test, receiver operating characteristic curve analyses and Spearman correlation test were used for statistical analyses.Malignant orbital tumors showed lower D (P <.001) and higher D (P = .002) than benign tumors. Setting a D value of 0.966 × 10 mm/s as the cut-off value, a diagnostic performance (AUC, 0.888; sensitivity, 100%; specificity, 82.35%) could be obtained for diagnosing malignant tumors. While setting a D value of 42.371 × 10 mm/s as cut-off value, a diagnostic performance could be achieved (AUC, 0.847; sensitivity, 90.00%; specificity, 70.59%). Poor or moderated correlations were found between IVIM-DWI and DCE-MRI parameters (D and Kep, r = 0.427, P = .027; D and Ve, r = 0.626, P <.001).IVIM-DWI is potentially useful for differentiating orbital malignant from benign tumors. Poor or moderate correlations exist between IVIM-DWI and DCE-MRI parameters. IVIM-DWI may be a useful adjunctive perfusion technique for the differential diagnosis of orbital tumors.

Background: Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has been used for assessing orbital lymphoproliferative disorders (OLPDs). However, only the mean values of quantitative parameters were obtained in previous studies and tumor heterogeneity was ignored., Purpose: To assess the value of DCE-MRI derived histogram parameters in differentiating malignant from benign OLPDs., Material and Methods: Forty-eight OLPDs patients (25 malignant and 23 benign) who had undergone DCE-MRI for pre-treatment evaluation were retrospectively included. Histogram parameters of K trans , k ep , and v e were calculated and compared between two groups using the independent sample's t-test. Receiver operating characteristic (ROC) curve analyses were used to determine the diagnostic value of each significant parameter. Multivariate stepwise logistic regression analysis was used to identify the independent predictors of malignant OLPDs., Results: Tenth k ep , mean k ep , median k ep , and 90th k ep were significantly higher in the malignant OLPD group than in the benign OLPD group. Tenth v e was significantly lower in the malignant OLPD group than in the benign OLPD group. Ninetieth k ep was the only independent predictor of malignant OLPDs ( P = 0.019), with an area under ROC curve of 0.828, a sensitivity of 92.00%, and a specificity of 78.26% at a cut-off value of 1.057 min -1 ., Conclusion: Histogram analysis of DCE-MRI derived parameters may help to differentiate malignant from benign OLPDs. The 90th k ep hold the potential as an independent predictor for malignant OLPDs.

Background: Previous studies indicated that dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) could serve as a useful biomarker for differentiating malignant from benign orbital lymphoproliferative disorders (OLPDs)., Purpose: To investigate the influence of different region of interest (ROI) selection methods on the measurements of DCE-MRI parameters, and their diagnostic ability in discriminating malignant from benign OLPDs., Study Type: Retrospective study., Population: In all, 46 patients with OLPDs (22 benign and 24 malignant)., Field Strength/sequence: 3.T DCE-MRI using a 2D turbo fast low angle shot sequence postcontrast., Assessment: DCE-MRI data were analyzed using three different ROI selection methods, including whole-tumor ROI (ROI WT ), single-slice ROI (ROI SS ) and hot-spot ROI (ROI HS ). Quantitative parameters (K trans , K ep , V e ) were calculated based on a modified Tofts model., Statistical Testing: Analysis of variance test, intraclass correlation coefficient (ICC), Bland-Altman plots, independent t-test, and receiver operating characteristic curve analyses were used for statistical analyses., Results: The time required for outlining ROI WT was significantly longer than ROI SS and ROI HS (P < 0.001). The measurements of DCE-MRI-derived parameters based on ROI HS demonstrated lowest ICC, followed by ROI SS and ROI WT . Malignant OLPDs showed significantly higher K ep than benign mimics (P < 0.001), while no significant differences were found on K trans (ROI WT , P = 0.535; ROI SS , P = 0.557; ROI HS , P = 0.400) and V e (ROI WT , P = 0.071; ROI SS , P = 0.079; ROI HS , P = 0.057). K ep -ROI WT showed the highest area under curve for differentiating malignant from benign OLPDs, followed by K ep -ROI SS , and Kep-ROI HS ; however, the differences were not significant (ROI WT vs. ROI SS , P = 0.407; ROI WT vs. ROI HS , P = 0.363; ROI SS vs. ROI HS , P = 0.887)., Data Conclusion: ROI selection methods could have an influence on the measurements of DCE-MRI parameters. Taking measurement time, reproducibility, and diagnostic ability into account, we suggest single-slice ROI to be used for differentiating malignant from benign OLPDs in clinical practice., Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1298-1305., (© 2017 International Society for Magnetic Resonance in Medicine.)

Purpose: To evaluate the correlation between histogram parameters derived from diffusion-kurtosis (DK) imaging and the clinical stage of nasopharyngeal carcinoma (NPC)., Results: High T-stage (T3/4) NPC showed significantly higher Kapp-mean (P = 0.018), Kapp-median (P = 0.029) and Kapp-90th (P = 0.003) than low T-stage (T1/2) NPC. High N-stage NPC (N2/3) showed significantly lower Dapp-mean (P = 0.002), Dapp-median (P = 0.002) and Dapp-10th (P < 0.001) than low N-stage NPC (N0/1). High AJCC-stage NPC (III/IV) showed significantly lower Dapp-10th (P = 0.038) than low AJCC-stage NPC (I/II). ROC analyses indicated that Kapp-90th was optimal for predicting high T-stage (AUC, 0.759; sensitivity, 0.842; specificity, 0.607), while Dapp-10th was best for predicting high N- and AJCC-stage (N-stage, AUC, 0.841; sensitivity, 0.875; specificity, 0.807; AJCC-stage, AUC, 0.671; sensitivity, 0.800; specificity, 0.588)., Materials and Methods: DK imaging data of forty-seven consecutive NPC patients were retrospectively analyzed. Apparent diffusion for Gaussian distribution (Dapp) and apparent kurtosis coefficient (Kapp) were generated using diffusion-kurtosis model. Histogram parameters, including mean, median, 10th, 90th percentiles, skewness and kurtosis of Dapp and Kapp were calculated. Patients were divided into low and high T, N and clinical stage based on American Joint Committee on Cancer (AJCC) staging system. Differences of histogram parameters between low and high T, N and AJCC stages were compared using t test. Multiple receiver operating characteristic (ROC) curves were used to determine and compare the value of significant parameters in predicting high T, N and AJCC stage, respectively., Conclusions: DK imaging-derived parameters correlated well with clinical stage of NPC, therefore could serve as an adjunctive imaging technique for evaluating NPC.

Objectives: To assess the value of dynamic contrast-enhanced MR imaging (DCE-MRI) in differentiating benign from malignant orbital lymphoproliferative disorders (OLPDs)., Methods: Thirty-nine patients with orbital lymphoproliferative disorders (21 malignant and 18 benign) underwent DCE-MRI scan for pre-treatment evaluation from March 2013 to December 2015. Both semi-quantitative (TTP, AUC, Slope max ) and quantitative (K trans , k ep , v e ) parameters were calculated, and compared between two groups. Receiver operating characteristic (ROC) curve analyses were used to determine the diagnostic value of each significant parameter., Results: Malignant OLPDs showed significantly higher k ep , lower v e , and lower AUC than benign OLPDs, while no significant differences were found on K trans , TTP and Slope max . ROC analyses indicated that v e exhibited the best diagnostic performance in predicting malignant OLPDs (cutoff value, 0.211; area under the curve, 0.896; sensitivity, 76.2%; specificity, 94.9%), followed by k ep (cutoff value, 0.853; area under the curve, 0.839; sensitivity, 85.7%; specificity, 89.9%)., Conclusion: DCE-MRI and specially its derived quantitative parameters of k ep and v e are promising metrics for differentiating malignant from benign OLPDs., (Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.)

Purpose: To determine the optimal combination of parameters derived from 3T multiparametric (conventional magnetic resonance imaging [MRI], diffusion-weighted [DW] and dynamic contrast-enhanced [DCE]) MRI for differentiating malignant from benign orbital lymphoproliferative disorders (OLPDs)., Materials and Methods: Forty patients with OLPDs (18 benign and 22 malignant) underwent conventional 3.0T MR, DW, and DCE-MRI examination for presurgery evaluation. Conventional MRI features (including tumor laterality, shape, number of involved quadrants, signal intensity on T 1 -weighted imaging (WI) and T 2 WI, flow void sign on T 2 WI, and findings suggestive of sinusitis) were reviewed, and multivariate logistic regression analysis was used to identify the most significant conventional MRI features. Apparent diffusion coefficient (ADC) and DCE-MRI derived parameters (area under curve [AUC], time to peak [TTP], maximum rise slope [Slope max ]) were measured and compared between two groups. Receiver operating characteristic (ROC) curve analyses were used to determine the diagnostic ability of each combination that was established based on identified qualitative and quantitative parameters., Results: Multivariate logistic regression analysis showed that the presence of flow void sign on T 2 WI significantly associated with benign OLPDs (P = 0.034). Malignant OLPDs demonstrated significantly lower ADC (P = 0.001) and AUC (P = 0.002) than benign mimics. ROC analyses indicted that, ADC alone showed the optimal sensitivity (threshold value, 0.886 × 10 -3 mm 2 /s; sensitivity, 90.9%), while a combination of no presence of flow void sign on T 2 WI + ADC ≤ 0.886 × 10 -3 mm 2 /s + AUC ≤ 7.366 showed optimal specificity (88.9%) in differentiating benign from malignant OLPDs., Conclusion: Multiparametric MRI can help to differentiate malignant from benign OLPDs. DWI offers optimal sensitivity, while the combination of conventional MRI, DWI, and DCE-MRI offers optimal specificity., Level of Evidence: 3 J. Magn. Reson. Imaging 2017;45:167-176., (© 2016 International Society for Magnetic Resonance in Medicine.)

Purpose: To determine whether intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) could detect parotid gland abnormalities in Sjögren's syndrome (SS) patients who were not identified by conventional MRI., Materials and Methods: Ten consecutive patients with clinically proven SS who were not identified by conventional MRI were assessed by IVIM MRI with a 3.0T MRI scanner. Quantitative parameters (tissue diffusivity, D; pseudodiffusion coefficient, D*; perfusion fraction, f) derived from IVIM MRI were compared between the SS group and healthy control group (n = 15). A receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of each significant parameter., Results: Excellent inter- and intrareader agreements were obtained during the measurement of D, f, and D* values (interreader, 0.980, 0.942, and 0.883; intrareader, 0.991, 0.952, and 0.896, respectively). All three parameters of the SS group were significantly higher than those of the healthy group (D, 1.049 ± 0.056 × 10(-3) mm(2) /s vs. 0.976 ± 0.116 × 10(-3) mm(2) /s, P = 0.012; D*, 20.410 ± 1.786 × 10(-3) mm(2) /s vs. 18.764 ± 2.433 × 10(-3) mm(2) /s, P = 0.013; f, 0.207 ± 0.003 vs. 0.182 ± 0.002, P = 0.004). ROC analysis showed that the f value had the best diagnostic performance (AUC, 0.712; Sensitivity, 0.80; Specificity, 0.57; Cutoff value, 0.185) in detecting the parotid gland abnormalities in early SS patients., Conclusion: IVIM MRI detected parotid gland abnormalities in early-stage SS patients. J. Magn. Reson. Imaging 2016;43:1455-1461., (© 2015 Wiley Periodicals, Inc.)

Rationale and Objectives: The aim of this study was to evaluate the added value of histogram analysis of apparent diffusion coefficient (ADC) maps in differentiating indeterminate orbital malignant tumors from benign tumors, compared to using magnetic resonance (MR) morphological features alone., Materials and Methods: We retrospectively evaluated 54 patients with orbital tumors from March 2013 to February 2015. All the patients were assessed by both routine MR and diffusion-weighted imaging, and divided into benign group and malignant group. Routine MR imaging features and histogram parameters derived from ADC maps, including mean ADC (ADCmean), median ADC (ADCmedian), standard deviation, skewness, kurtosis, and 10th and 90th percentiles of ADC (ADC10 and ADC90), were compared between two groups. Univariate and multivariate logistic regression analyses were used to identify the most valuable variables in predicting malignancy. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of significant variables., Results: Multivariate logistic regression analysis indicated that two or more quadrants involved, iso-intense on T2-weighted imaging (T2WI), and ADC10 were significant predictors for orbital malignancy. By using model 2 (iso-intense on T2WI + two or more quadrants involved + ADC10 < 0.990) as the criterion, higher AUC and specificity could be achieved than by using model 1 (iso-intense on T2WI + two or more quadrants involved) alone, (model 2 vs model 1; area under curve (AUC), 0.827 vs 0.793; sensitivity, 65.4% vs 69.2%; specificity, 100% vs 89.3%)., Conclusions: Iso-intense on T2WI, two or more quadrants involved, and ADC10 are risk factors for orbital malignancy. Histogram analysis of ADC map might provide added value in predicting orbital malignancy., (Copyright © 2015 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the effect of age, gender and laterality on the intravoxel incoherent motion (IVIM) MR imaging measurements of parotid glands in healthy participants at 3.0-T MRI., Methods: A total of 108 healthy participants were prospectively recruited. IVIM MRI scan was performed using a 3.0-T MR scanner, and corresponding parameters (perfusion fraction, f; pseudodiffusion coefficient, D*; tissue diffusivity, D) were derived from biexponential fitting of IVIM data. Pearson correlation analysis was performed to determine the association between the IVIM MRI parameters and age. The parameter difference between male and female participants or between left and right parotid glands was compared using unpaired or paired t test, respectively., Results: Excellent interreader and intrareader agreements on the measurements of IVIM MRI parameters were achieved. Both D and f values correlated inversely with the age in both left and right parotid glands (p < 0.05) while D* value did not (p > 0.05). Male participants had higher IVIM MRI parameters than the female participants in both left and right glands (p < 0.05). No significant differences were found in the IVIM MRI parameters between left and right glands in both male and female participants (p > 0.05)., Conclusion: The IVIM MRI parameters are age and gender dependent, but not laterality dependent. Age- and gender-related effect should be taken into consideration in future IVIM MRI studies for parotid glands., Advances in Knowledge: (1) Both D and f values correlated inversely with the age in healthy parotid glands, while D* value did not. (2) The parotid glands of males showed higher IVIM MRI parameters than that of females. (3) There were no significant differences on the IVIM MRI parameters between the left and right glands. (4) Age- and gender-related effect should be taken into consideration in future IVIM MRI studies for parotid glands.

Purpose: To study the MRI features (based on LI-RADS) and clinical characteristics of P53-mutated hepatocellular carcinoma (HCC) patients. Patients and Methods: This study enrolled 344 patients with histopathologically confirmed HCC (P53-mutated group [n = 196], non-P53-mutated group [n = 148]). We retrospectively evaluated the preoperative MRI features, clinical and pathologic features of the lesions and assigned each lesion according to the LI-RADS. MRI findings, clinical features, and pathologic findings were compared using the Student's t test, χ 2 test, and multivariable regression analysis. Results: Most HCC patients were categorized as LR-5. On multivariate analysis, the Edmondson–Steiner grade (odds ratio, 2.280; 95% CI: 1.268, 4.101; p = 0.006) and rim enhancement (odds ratio, 2.517; 95% CI: 1.095, 5.784; p = 0.030) were found to be independent variables associated with P53-mutated HCC. In the group of HCC lesions with the largest tumor diameter (LTD) greater than or equal to 10mm and less than or equal to 20mm, enhancing capsule was an independent predictor of P53-mutated HCC (odds ratio, 6.200; 95% CI: 1.116, 34.449; p = 0.037). Among the HCC lesions (20 mm ˂ LTD ≤ 50 mm), corona enhancement (odds ratio, 2.102; 95% CI: 1.022, 4.322; p = 0.043) and nodule-in-nodule architecture (odds ratio, 2.157; 95% CI: 1.033, 4.504; p = 0.041) were found to be independent risk factors for P53 mutation. Among the HCC lesions (50 mm ˂ LTD ≤ 100 mm), diameter (odds ratio, 1.035; 95% CI: 1.001, 1.069; p = 0.044) and AFP ≥ 400 (ng/mL) (odds ratio, 3.336; 95% CI: 1.052, 10.577; p = 0.041) were found to be independent variables associated with P53-mutated HCC. Conclusion: Poor differentiation and rim enhancement are potential predictive biomarkers for P53-mutated HCC, while HCCs of different diameters have different risk factors for predicting P53 mutations. [ABSTRACT FROM AUTHOR]

Objective: To investigate the value of Dixon magnetic resonance imaging (MRI)-based quantitative parameters of extraocular muscles (EOMs), intraorbital fat (IF), and lacrimal glands (LGs) in staging patients with thyroid-associated ophthalmopathy (TAO). Methods: Two hundred patients with TAO (211 active and 189 inactive eyes) who underwent Dixon MRI for pretreatment evaluation were retrospectively enrolled and divided into training (169 active and 151 inactive eyes) and validation (42 active and 38 inactive eyes) cohorts. The maximum, mean, and minimum values of the signal intensity ratio (SIR), fat fraction (FF), and water fraction (WF) of EOMs, IF, and LGs were measured and compared between the active and inactive groups in the training cohort. Binary logistic regression analysis, receiver operating characteristic curve analysis, and the Delong test were used for further statistical analyses, as appropriate. Results: Compared with inactive TAOs, active TAOs demonstrated significantly greater EOM-SIRmax, EOM-SIRmean, EOM-SIRmin, IF-SIRmax, IF-SIRmean, LG-SIRmax, LG-SIRmean, EOM-WFmean, EOM-WFmin, IF-WFmax, IF-WFmean, and LG-WFmean and lower EOM-FFmax, EOM-FFmean, IF-FFmean, IF-FFmin, and LG-FFmean values (all p < 0.05). The EOM-SIRmean, LG-SIRmean, and LG-FFmean values were independently associated with active TAO (all p < 0.05). The combination of the EOM-SIRmean, LG-SIRmean, and LG-FFmean values showed better performance than the EOM-SIRmean value alone in staging TAO in both the training (AUC, 0.820 vs 0.793; p = 0.016) and validation (AUC, 0.751 vs 0.733, p = 0.341) cohorts. Conclusion: Dixon MRI-based parameters of EOMs, LGs, and IF are useful for differentiating active from inactive TAO. The integration of multiple parameters can further improve staging performance. Critical relevance statement: In this study, the authors explored the combined value of quantitative parameters of EOMs, IF, and LGs derived from Dixon MRI in staging TAO patients, which can support the establishment of a proper therapeutic plan. Key Points: The quantitative parameters of EOMs, LGs, and IF are useful for staging TAO. The EOM-SIRmean, LG-SIRmean, and LG-FFmean values were found to independently correlate with active TAO. Joint evaluation of orbital tissue improved the ability to assess TAO activity. [ABSTRACT FROM AUTHOR]

In magnetic resonance (MR) image reconstruction, the orthogonal matching pursuit (OMP) is widely recognized for its simplicity and competitive performance. However, OMP designs a termination condition based on some prior information such as sparsity and noise intensity. In practice, the unknown prior information of MR images cannot guarantee accurate reconstruction. To make OMP suitable for magnetic resonance imaging (MRI), we propose an automatic threshold OMP algorithm based on QR decomposition (ATOMP-QR). The termination condition of ATOMP-QR, which utilizes the mutual incoherence property of the sensing matrix, is related to whether the residual vector includes the orthogonal projection component of measurements. Then, to avoid the computation of pseudo-inverse and accelerate reconstruction speed, we perform QR decomposition on the measurement matrix. We conduct the MRI experiments to evaluate the superiority and effectiveness of ATOMP-QR in peak signal-to-noise ratio (PSNR), structure similarity index measure (SSIM), and running time. Specifically, for the T1-w image with a sparsity of 10, the PSNR was improved from 24 to 32 dB; the SSIM was increased from 0.87 to 0.99. The maximum time consumed decreased from 0.2276 to 0.0107 s. [ABSTRACT FROM AUTHOR]

In the realm of medical diagnosis, recent strides in deep neural network-guided magnetic resonance imaging (MRI) restoration have shown promise. Nevertheless, persistent drawbacks overshadow these advancements. Challenges persist in balancing acquisition speed and image quality, while existing methods primarily focus on singular tasks like MRI reconstruction or super-resolution (SR), neglecting the interplay between these tasks. To tackle these challenges, this paper introduces the mutual co-attention network (MCAN) specifically designed to concurrently address both MRI reconstruction and SR tasks. Comprising multiple mutual cooperation attention blocks (MCABs) in succession, MCAN is tailored to maintain consistency between local physiological details and global anatomical structures. The intricately crafted MCAB includes a feature extraction block, a local attention block and a global attention block. Additionally, to ensure data fidelity without compromising acquired data, we propose the channel-wise data consistency block. Thorough experimentation on the IXI and fastMRI dataset showcases MCAN's superiority over existing state-of-the-art methods. Both quantitative metrics and visual quality assessments validate the enhanced performance of MCAN in MRI restoration. The findings underscore MCAN's potential in significantly advancing therapeutic applications. By mitigating the trade-off between acquisition speed and image quality while simultaneously addressing both MRI reconstruction and SR tasks, MCAN emerges as a promising solution in the domain of magnetic resonance image restoration. [ABSTRACT FROM AUTHOR]

Purpose: The etiological features of stroke in young adults are different from those in older adults. We aimed to investigate the impact of high-resolution vessel wall imaging (HRVWI) on etiologic diagnosis in young adults with ischemic stroke or transient ischemic attack (TIA). Methods: A total of 253 young adults (aged 18–45 years) who consecutively underwent HRVWI for clarifying stroke etiology were retrospectively recruited. Two experienced neurologists classified stroke etiology for each patient using Trial of Org 10,172 in Acute Stroke Treatment categories with and without the inclusion of HRVWI diagnosis. Multivariate logistic regression was performed to determine which etiologic category would be significantly impacted after including HRVWI. Results: The etiologic classification was altered in 39.1% (99/253) of patients after including HRVWI in the conventional investigations. The proportion of patients classified as having stroke of undetermined etiology (SUE) and the proportion of patients classified as having small-artery occlusion (SAO) both significantly decreased (36.4 to 13.8% and 9.1 to 2.0%), whereas the proportion of patients classified as having large artery atherosclerosis (LAA) significantly increased (28.5 to 58.1%) (all P < 0.001). The inclusion of HRVWI had a significant diagnostic impact on young adults who were primarily classified as SAO (odds ratio [OR] 14.4, 95% confidence interval [CI] [2.9, 71.8], P < 0.001) or SUE (OR 8.3, 95% CI [2.2, 31.5], P < 0.01). Conclusions: HRVWI had a substantial impact on etiologic classification in young adults with ischemic stroke or TIA, particularly for those primarily classified as having SAO or SUE. This impact of HRVWI will be beneficial for therapeutic decision-making. [ABSTRACT FROM AUTHOR]

Background: World Health Organization classification and Masaoka‐Koga stage are widely used for thymic epithelial tumors (TETs). Reduced field‐of‐view (rFOV) diffusion‐weighed imaging (DWI) proved to improve the image quality. Dynamic contrast‐enhanced (DCE) MRI was commonly used in evaluating tumors. Purpose: To investigate the value of multiparametric MRI in evaluating TETs. Study Type: Retrospective. Subjects: Eighty‐seven participants including 38 low risk (52.08 ± 14.19 years), 30 high risk (52.40 ± 11.35 years), and 19 thymic carcinoma patients (59.76 ± 10.78 years). Field strength/Sequence: A 3 T, turbo spin echo imaging, echo planar imaging, volumetric interpolated breath‐hold examination with radial acquisition trajectory. Assessment DCE‐MRI and apparent diffusion coefficient (ADC) variables were compared. Diagnostic performances of single significant factor and combined model were compared. Statistical Tests: Parameters were compared using one‐way ANOVA or independent‐samples t test. Logistic regression was employed to investigate the combined model. Receiver operating curves (ROC) and DeLong's test were used to compare the diagnostic efficiency. Results: ADC, Ktrans, and kep values were significantly different among low‐risk, high‐risk and carcinoma group (ADC, 1.279 ± 0.345 × 10−3 mm2/sec, 0.978 ± 0.260 × 10−3 mm2/sec, 0.661 ± 0.134 × 10−3 mm2/sec; Ktrans 0.167 ± 0.071 min−1, 0.254 ± 0.136 min−1, 0.393 ± 0.110 min−1; kep 0.345 ± 0.113 min−1, 0.560 ± 0.269 min−1, 0.872 ± 0.149 min−1). They were significantly different for early stage and advanced stage (ADC, 1.270 ± 0.356 × 10−3 mm2/sec vs. 0.845 ± 0.251 × 10−3 mm2/sec; Ktrans 0.179 ± 0.092 min−1 vs. 0.304 ± 0.142 min−1; kep 0.370 ± 0.181 min−1 vs. 0.674 ± 0.362 min−1). The combination of them had highest diagnostic efficiency for WHO classification (AUC, 0.925; sensitivity, 83.7%; specificity, 89.5%), clinical stage (AUC, 0.879; sensitivity, 80.9%; specificity, 82.5%). Data Conclusion: Multiparametric MRI model may be useful for discriminating WHO classification and clinical stage of TETs. Evidence Level 4 Technical Efficiency: Stage 2 [ABSTRACT FROM AUTHOR]

Background: MR imaging has been applied to determine therapeutic response to glucocorticoid (GC) before treatment in thyroid‐associated ophthalmopathy (TAO), while the performance was still poor. Purpose: To investigate the value of T2‐weighted imaging (T2WI)‐derived radiomics for pretreatment determination of therapeutic response to GC in TAO patients, and compare its diagnostic performance with that of semiquantitative parameters. Study Type: Retrospective. Population: A total of 110 patients (49 ± 12 years; male/female, n = 48/62; responsive/unresponsive, n = 62/48), divided into training (n = 78) and validation (n = 32) cohorts. Field Strength/Sequence: 3.0 T, T2‐weighted fast spin echo. Assessment: W.C. and H.H. (6 and 10 years of experience, respectively) performed the measurements. Maximum, mean, and minimum signal intensity ratios (SIRs) of extraocular muscle (EOM) bellies were collected to construct a semiquantitative imaging model. Radiomics features from volumes of interest covering EOM bellies were extracted and three machine learning‐based (logistic regression [LR]; decision tree [DT]; support vector machine [SVM]) models were built. Statistical Tests: The diagnostic performances of models were evaluated using receiver operating characteristic curve analyses, and compared using DeLong test. Two‐sided P < 0.05 was considered statistically significant. Results: The responsive group showed higher minimum signal intensity ratio (SIRmin) of EOMs than the unresponsive group (training: 1.46 ± 0.34 vs. 1.18 ± 0.39; validation: 1.44 ± 0.33 vs. 1.19 ± 0.20). In both cohorts, LR‐based radiomics model demonstrated good diagnostic performance (area under the curve [AUC] = 0.968, 0.916), followed by DT‐based (AUC = 0.933, 0.857) and SVM‐based models (AUC = 0.919, 0.855). All three radiomics models outperformed semiquantitative imaging model (SIRmin: AUC = 0.805) in training cohort. In validation cohort, only LR‐based radiomics model outperformed that of SIRmin (AUC = 0.745). The nomogram integrating LR‐based radiomics signature and disease duration further elevated the diagnostic performance in validation cohort (AUC: 0.952 vs. 0.916, P = 0.063). Data Conclusion: T2WI‐derived radiomics of EOMs, together with disease duration, provides a promising noninvasive approach for determining therapeutic response before GC administration in TAO patients. Level of Evidence: 3 Technical Efficacy: Stage 4 [ABSTRACT FROM AUTHOR]

Purpose: Thyroid-associated ophthalmopathy (TAO) is a debilitating and sight-threatening autoimmune disease that severely impairs patients' quality of life. Besides the most common ophthalmic manifestations, the emotional and psychiatric disturbances are also usually observed in clinical settings. This study was to investigate the interhemispheric functional connectivity alterations in TAO patients using resting-state functional magnetic resonance imaging (rs-fMRI). Methods: Twenty-eight TAO patients and 22 healthy controls (HCs) underwent rs-fMRI scans. Static and dynamic voxel-mirrored homotopic connectivity (VMHC) values were calculated and compared between the two groups. A linear support vector machine (SVM) classifier was used to examine the performance of static and dynamic VMHC differences in distinguishing TAOs from HCs. Results: Compared with HCs, TAOs showed decreased static VMHC in lingual gyrus (LG)/calcarine (CAL), middle occipital gyrus, postcentral gyrus, superior parietal lobule, inferior parietal lobule, and precuneus. Meanwhile, TAOs demonstrated increased dynamic VMHC in orbitofrontal cortex (OFC). In TAOs, static VMHC in LG/CAL was positively correlated with visual acuity (r = 0.412, P = 0.036), whilst dynamic VMHC in OFC was positively correlated with Hamilton Anxiety Rating Scale (HARS) score (r = 0.397, P = 0.044) and Hamilton Depression Rating Scale (HDRS) score (r = 0.401, P = 0.042). The SVM model showed good performance in distinguishing TAOs from HCs (area under the curve, 0.971; average accuracy, 94%). Conclusion: TAO patients had altered static and dynamic VMHC in the occipital, parietal, and orbitofrontal areas, which could serve as neuroimaging prediction markers of TAO. [ABSTRACT FROM AUTHOR]

Background: Several magnetic resonance imaging (MRI) sequences have been applied to assess injured glands but without histological validation. Purpose: To evaluate longitudinal changes in multiparametric MRI (mp‐MRI) of irradiated salivary glands in a rat model and investigate correlations between mp‐MRI and histological findings. Study Type: Prospective. Animal Model: Submandibular glands of 36 rats were radiated using a single dose of 15 Gy X‐ray (irradiation [IR] group), and 6 other rats were enrolled into sham‐IR group. mp‐MRI were scanned 1 day after sham‐IR (n = 6), or 1, 2, 4, 8, 12, 24 weeks after IR (n = 36, 6 per subgroup). Field Strength/Sequence: A 3.0‐T/Diffusion‐weighted imaging (DWI), readout‐segmented echo‐planar imaging (EPI) sequence; intravoxel incoherent motion DWI, single‐shot EPI sequence; T1 mapping, dual‐flip‐angle gradient‐echo sequence with volumetric interpolated breath‐hold examination; T2 mapping, turbo spin‐echo sequence. Assessment: Parameters including apparent diffusion coefficient (ADC), pure diffusion coefficient (D), pseudo‐diffusion coefficient (D*), perfusion fraction (f), T1 and T2 value were obtained. Histological examinations, including hematoxylin and eosin staining (for acinar cell fraction [AC%] detection), Masson's trichrome staining (for degree of fibrosis [F%] determination) and CD34‐immunohistochemical staining (for microvessel density [MVD] calculation), were performed at corresponding time points. Statistical Tests: One‐way analysis of variance was used to compare the mp‐MRI and histological parameters among different groups. Spearman correlation analysis was applied to determine the correlation between mp‐MRI and histological parameters. Two‐sided P ≤ 0.05 was considered statistically significant. Results: Changes of mp‐MRI parameters (ADC, D, D*, f, T1, T2) and histological results (AC%, F%, MVD) among the seven groups were all significant. ADC, D, and T2 values negatively correlated with AC% (ADC, r = −0.728; D, r = −0.773; T2, r = −0.600), f positively correlated with MVD (r = 0.496), and T1 values positively correlated with F% (r = 0.714). Data Conclusion: mp‐MRI might be able to noninvasively and quantitatively evaluate the dynamic pathological changes within the irradiated salivary glands. Evidence Level: 1 Technical Efficacy: Stage 2 [ABSTRACT FROM AUTHOR]

Background: The prognostic significance of hyperperfusion after reperfusion therapy in patients with acute ischemic stroke (AIS) remains controversial. Purpose: To investigate the clinical factors associated with hyperperfusion, and the 90‐day prognostic value of hyperperfusion after mechanical thrombectomy in AIS patients. Study Type: Retrospective. Population/Subjects: Fifty‐four AIS patients who underwent mechanical thrombectomy. Field Strength/Sequence: Time‐of‐flight MR angiography, pulsed arterial spin labeling (ASL), diffusion‐weighted imaging (DWI), and susceptibility‐weighted imaging were performed at 3.0T within 1 week after thrombectomy. Assessment: Clinical factors including demographics, risk factors, stroke and treatment characteristics were collected and assessed. Hyperperfusion on ASL was defined as a focal increased cerebral blood flow on the affected side ≥130% of its mirror counterpart. Good clinical outcome at 90 days was defined as modified Rankin Scale score of 0–2. Statistical Tests: The interrater agreement was assessed using Cohen's kappa or the intraclass correlation coefficient. The relationship between hyperperfusion and clinical factors were analyzed by appropriate univariate statistics. Predictors of 90‐day functional outcome were assessed by univariate analyses followed by multivariate logistic regression analysis and receiver‐operating‐characteristic curves. Results: Thirty‐six (66.7%) patients developed hyperperfusion on ASL after thrombectomy. Hyperperfusion was significantly correlated with successful recanalization (P < 0.05) and improvement of National Institutes of Health Stroke Scale scores at 24 hours (NIHSS24h) (P < 0.05). A higher incidence of hemorrhage transformation was observed in patients with hyperperfusion than those without (63.9% vs. 50.0%), but no significant difference was found (P = 0.327). NIHSS24h (odds ratio [OR], 0.75, [95% confidence interval [CI] 0.62–0.91], P < 0.05), lesion volume on diffusion‐weighted imaging (OR, 0.97, [95% CI 0.95–1.00], P < 0.05), and hyperperfusion on ASL (OR, 9.8, [95% CI 1.7–55.3], P < 0.05) were independent variables for predicting good functional outcomes. Data Conclusion: Hyperperfusion on ASL correlated with successful recanalization and may be an independent prognostic marker for good neurological outcomes at 90 days in AIS patients after mechanical thrombectomy. Level of Evidence: 4 Technical Efficacy Stage: 2 [ABSTRACT FROM AUTHOR]

Background: Diffusion kurtosis imaging (DKI) is a technique based on the theory that the diffusion of water follows non-Gaussian distribution; until now, few studies have explored the usefulness of DKI in differentiating parotid gland tumors. Purpose: To evaluate the potential of DKI in the characterization of parotid gland tumors. Material and Methods: DKI was performed in 40 patients with parotid gland tumors (33 benign, 7 malignant). DKI parameters including apparent diffusion coefficient (Dapp) and apparent kurtosis coefficient (Kapp) were obtained using the DK model and compared. Intraclass correlation coefficient (ICC) was used to evaluate inter-observer agreement of DKI derived parameters. Results: Excellent inter-observer agreements (Dapp, ICC = 0.988; Kapp, ICC = 0.985) were achieved during quantitative measurements. There were no significant differences in Dapp (P = 0.055) and Kapp (P = 0.915) between the benign and malignant groups. In the subgroup analyses, pleomorphic adenomas showed higher Dapp (P < 0.001) and lower Kapp (P = 0.037) than malignant tumors. Combination of Dapp and Kapp showed optimal discriminative value (area under curve [AUC] = 0.913; sensitivity = 88.89%; specificity = 85.71%). Pleomorphic adenomas also showed higher Dapp (P < 0.001) and lower Kapp (P < 0.001) than Warthin's tumors. A combination of Dapp and Kapp showed optimal discriminative value (AUC = 1.000; sensitivity = 100%; specificity = 100%). Warthin's tumors demonstrated higher Kapp than malignant tumors (P < 0.001), while no significant difference was found on Dapp (P = 0.448). The AUC, sensitivity, and specificity of Kapp for discriminating Warthin's tumors from malignant tumors at an optimal threshold of 0.735 were 0.905, 88.89%, and 85.71%, respectively. Conclusion: DKI may be a promising imaging technique for characterizing parotid gland tumors. [ABSTRACT FROM AUTHOR]

Background To clarify the nature of cervical malignant lymphadenopathy is highly important for the diagnosis and differential diagnosis of head and neck tumors. Purpose To investigate the role of first-order apparent diffusion coefficient (ADC) histogram analysis for differentiating lymphoma from metastatic lymph nodes of squamous cell carcinoma (SCC) in the head and neck region. Material and Methods Diffusion-weighted imaging (DWI) data of 67 patients (lymphoma, n = 20; SCC, n = 47) with malignant lymphadenopathy were retrospectively analyzed. The SCC group was divided into nasopharyngeal SCC and non-nasopharyngeal SCC groups. The ADC histogram features (ADC10, ADC25, ADCmean, ADCmedian, ADC75, ADC90, skewness, and kurtosis) were derived and then compared by independent-samples t-test and one-way analysis of variance test, respectively. Receiver operating characteristic curve analyses were employed to investigate diagnostic performance of the significant parameters. Results Lymphoma showed significantly lower ADCmean, ADCmedian, ADC75, and ADC90 than SCC (all P < 0.05). Setting ADC90 = 0.719 × 10-3 mm2/s as the threshold value, optimal diagnostic performance was achieved (area under the curve [AUC] = 0.719, sensitivity = 95.7%, specificity = 50.0%). Subgroup analyses showed no significant difference between lymphoma and NPC (all P > 0.05). Lymphoma showed significantly lower ADC25, ADCmean, ADCmedian, ADC75, and ADC90 than non-nasopharyngeal SCC (all P < 0.05). Optimal diagnostic performance (AUC = 0.847, sensitivity = 86.7%, specificity = 80.0%) could be achieved when setting ADC90 = 0.943 × 10-3 mm2/s as the threshold value. Conclusion Given its limitations, our study has shown that first-order ADC histogram analysis is capable of differentiating lymphoma from metastatic lymph nodes of SCC, especially those of non-nasopharyngeal SCC. [ABSTRACT FROM AUTHOR]