Reproducibility for carotid wall segmentation using T1-weighted DANTE-SPACE sequence on high-resolution 3-T carotid MRI.

BACKGROUND: T1-weighted (T1W) magnetic resonance imaging (MRI) using the delay alternating with nutation for excitation-sampling perfection with application-optimized contrasts using different flip angle evolution (DANTE-SPACE) is the preferred imaging technique for evaluation of the vessel wall. PURPOSE: To evaluate the intra- and inter-rater reproducibility of carotid wall segmentation on T1W DANTE-SPACE in patients with symptomatic (acute stroke or transient ischemic attack) internal carotid artery (ICA) stenosis. MATERIAL AND METHODS: This prospective study included 25 patients with acute (≤3 months) stroke or transient ischemic attack and 50%-99% stenosis of the ICA. All patients underwent 3.0-T high-resolution carotid MRI. Two radiologists independently performed the manual segmentation of the vessel wall and inner lumen of the bilateral carotid artery on DANTE-SPACE. The intraclass correlation coefficient (ICC), Dice similarity coefficient (DSC), and Hausdorff distance (HD) were calculated. RESULTS: The ICCs for intra-rater reproducibility of carotid wall volume, inner lumen volume, and normalized wall index were 0.965, 0.990, and 0.962, respectively. The ICCs for inter-rater reproducibility of carotid wall volume, inner lumen, and normalized wall index were 0.856, 0.981, and 0.904. DSC and HD for intra- and inter-rater reproducibility of carotid wall segmentation were as follows: 0.873 and 0.809 (DSC); and 0.079 and 0.118 (HD), respectively. For evaluation of reproducibility only in the carotid artery with symptomatic stenosis, the ICCs for intra- and inter-rater reproducibility indicated all perfect agreement. CONCLUSION: T1W DANTE-SPACE is a reproducible sequence for evaluation of the carotid wall using carotid MRI in patients with symptomatic ICA stenosis.

MR-self Noise2Noise: self-supervised deep learning-based image quality improvement of submillimeter resolution 3D MR images.

OBJECTIVES: The study aimed to develop a deep neural network (DNN)-based noise reduction and image quality improvement by only using routine clinical scans and evaluate its performance in 3D high-resolution MRI. METHODS: This retrospective study included T1-weighted magnetization-prepared rapid gradient-echo (MP-RAGE) images from 185 clinical scans: 135 for DNN training, 11 for DNN validation, 20 for qualitative evaluation, and 19 for quantitative evaluation. Additionally, 18 vessel wall imaging (VWI) data were included to evaluate generalization. In each scan of the DNN training set, two noise-independent images were generated from the k-space data, resulting in an input-label pair. 2.5D U-net architecture was utilized for the DNN model. Qualitative evaluation between conventional MP-RAGE and DNN-based MP-RAGE was performed by two radiologists in image quality, fine structure delineation, and lesion conspicuity. Quantitative evaluation was performed with full sampled data as a reference by measuring quantitative error metrics and volumetry at 7 different simulated noise levels. DNN application on VWI was evaluated by two radiologists in image quality. RESULTS: Our DNN-based MP-RAGE outperformed conventional MP-RAGE in all image quality parameters (average scores = 3.7 vs. 4.9, p < 0.001). In the quantitative evaluation, DNN showed better error metrics (p < 0.001) and comparable (p > 0.09) or better (p < 0.02) volumetry results than conventional MP-RAGE. DNN application to VWI also revealed improved image quality (3.5 vs. 4.6, p < 0.001). CONCLUSION: The proposed DNN model successfully denoises 3D MR image and improves its image quality by using routine clinical scans only. KEY POINTS: • Our deep learning framework successfully improved conventional 3D high-resolution MRI in all image quality parameters, fine structure delineation, and lesion conspicuity. • Compared to conventional MRI, the proposed deep neural network-based MRI revealed better quantitative error metrics and comparable or better volumetry results. • Deep neural network application to 3D MRI whose pulse sequences and parameters were different from the training data showed improvement in image quality, revealing the potential to generalize on various clinical MRI.

What did the pandemic teach us about effective health communication? Unpacking the COVID-19 infodemic.

BACKGROUND: The spread of unvetted scientific information about COVID-19 presents a significant challenge to public health, adding to the urgency for increased understanding of COVID-19 information-seeking preferences that will allow for the delivery of evidence-based health communication. This study examined factors associated with COVID-19 information-seeking behavior. METHODS: An online survey was conducted with US adults (N = 1800) to identify key interpersonal (e.g., friends, health care providers) and mediated (e.g., TV, social media) sources of COVID-19 information. Logistic regression models were fitted to explore correlates of information-seeking. RESULTS: Study findings show that the first sought and most trusted sources of COVID-19 information had different relationships with sociodemographic characteristics, perceived discrimination, and self-efficacy. Older adults had greater odds of seeking information from print materials (e.g., newspapers and magazines) and TV first. Participants with less educational attainment and greater self-efficacy preferred interpersonal sources first, with notably less preference for mass media compared to health care providers. Those with more experiences with discrimination were more likely to seek information from friends, relatives, and co-workers. Additionally, greater self-efficacy was related to increased trust in interpersonal sources. CONCLUSION: Study results have implications for tailoring health communication strategies to reach specific subgroups, including those more vulnerable to severe illness from COVID-19. A set of recommendations are provided to assist in campaign development.

Aberrant Cortical Layer Development of Brain Organoids Derived from Noonan Syndrome-iPSCs.

Noonan syndrome (NS) is a genetic disorder mainly caused by gain-of-function mutations in Src homology region 2-containing protein tyrosine phosphatase 2 (SHP2). Although diverse neurological manifestations are commonly diagnosed in NS patients, the mechanisms as to how SHP2 mutations induce the neurodevelopmental defects associated with NS remain elusive. Here, we report that cortical organoids (NS-COs) derived from NS-induced pluripotent stem cells (iPSCs) exhibit developmental abnormalities, especially in excitatory neurons (ENs). Although NS-COs develop normally in their appearance, single-cell transcriptomic analysis revealed an increase in the EN population and overexpression of cortical layer markers in NS-COs. Surprisingly, the EN subpopulation co-expressing the upper layer marker SATB2 and the deep layer maker CTIP2 was enriched in NS-COs during cortical development. In parallel with the developmental disruptions, NS-COs also exhibited reduced synaptic connectivity. Collectively, our findings suggest that perturbed cortical layer identity and impeded neuronal connectivity contribute to the neurological manifestations of NS.

Identification of the intraparotid facial nerve on MRI: a systematic review and meta-analysis.

OBJECTIVES: Accurate preoperative localization of the intraparotid facial nerve (IFN) on MRI could reduce intraoperative injury. This study aimed to assess the detection rate of the IFN and its branches on MRI. METHODS: PubMed-MEDLINE and Embase databases were searched for articles published up to October 2019. The inclusion criteria were (a) adults, (b) MRI-based identification of IFN by radiologists, (c) original articles, and (d) detailed results to assess the proportion of visible IFN. Two radiologists reviewed the original articles. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to determine the quality of the selected studies. The DerSimonian-Laird random effects model was utilized to calculate the pooled estimates. Between-studies heterogeneity was evaluated using the chi-squared statistic test and Higgins' inconsistency index (I2). A subgroup meta-regression was performed to explore the factors causing study heterogeneity. RESULTS: Nine original articles with 209 subjects were included. MRI reported a high pooled detection rate of 99.8% (95% CI, 98.4-100%) for the main trunk of the IFN. The pooled rates for the temporofacial and cervicofacial branches were 90.4% (95% CI, 84.1-96.7%) and 96.3% (95% CI, 96.1-99.5%), respectively. Heterogeneity was detected only in the temporofacial branch (I2 = 83%) as a result of both slice thickness and the use of steady-state sequences with diffusion-weighted imaging (DWI) implementation. CONCLUSIONS: MRI showed an overall high detection rate of the IFN and its branches. Furthermore, an increased identification was observed in studies that used a slice thickness of < 1 mm and steady-state sequences with DWI implementation. KEY POINTS: • MRI showed an overall high detection rate of the intraparotid facial nerve and its branches. • Higher detection rate was observed in studies that used a slice thickness of < 1 mm and steady-state sequences with diffusion-weighted imaging.

Radiomics may increase the prognostic value for survival in glioblastoma patients when combined with conventional clinical and genetic prognostic models.

OBJECTIVES: To evaluate the additional prognostic value of multiparametric MR-based radiomics in patients with glioblastoma when combined with conventional clinical and genetic prognostic factors. METHODS: In this single-center study, patients diagnosed with glioblastoma between October 2007 and December 2019 were retrospectively screened and grouped into training and test sets with a 7:3 distribution. Segmentations of glioblastoma using multiparametric MRI were performed automatically via a convolutional-neural network. Prognostic factors in the clinical model included age, sex, type of surgery/post-operative treatment, and tumor location; those in the genetic model included statuses of isocitrate dehydrogenase-1 mutation and O-6-methylguanine-DNA-methyltransferase promoter methylation. Univariate and multivariate Cox proportional hazards analyses were performed for overall survival (OS) and progression-free survival (PFS). Integrated time-dependent area under the curve (iAUC) for survival was calculated and compared between prognostic models via the bootstrapping method (performances were validated with prediction error curves). RESULTS: Overall, 120 patients were included (training set, 85; test set, 35). The mean OS and PFS were 25.5 and 18.6 months, respectively. The prognostic performances of multivariate models improved when radiomics was added to the clinical model (iAUC: OS, 0.62 to 0.73; PFS, 0.58 to 0.66), genetic model (iAUC: OS, 0.59 to 0.67; PFS, 0.59 to 0.65), and combined model (iAUC: OS, 0.65 to 0.73; PFS, 0.62 to 0.67). In the test set, the combined model (clinical, genetic, and radiomics) demonstrated robust validation for risk prediction of OS and PFS. CONCLUSIONS: Radiomics increased the prognostic value when combined with conventional clinical and genetic prognostic models for OS and PFS in glioblastoma patients. KEY POINTS: • CNN-based automatic segmentation of glioblastoma on multiparametric MRI was useful in extracting radiomic features. • Patients with glioblastoma with high-risk radiomics scores had poor overall survival (hazards ratio 8.33, p < 0.001) and progression-free survival (hazards ratio 3.76, p < 0.001). • MR-based radiomics improved the survival prediction when combined with clinical and genetic factors (overall and progression-free survival iAUC from 0.65 to 0.73 and 0.62 to 0.67, respectively; both p < 0.001).

Multiphasic Computed Tomography Angiography Findings for Identifying Pseudo-Occlusion of the Internal Carotid Artery.

BACKGROUND AND PURPOSE: Differentiation between pseudo-occlusion and true occlusion of internal carotid artery (ICA) is important in treatment planning for acute ischemic stroke patients. We compared the findings of multiphasic computed tomography angiography between cervical ICA pseudo-occlusion and true occlusion at the cervical ICA in patients with anterior circulation acute ischemic stroke to determine their diagnostic value. METHODS: Thirty patients with nonvisualization of the proximal ICA were included. Diagnosis of pseudo- or true occlusion of the ICA was made based on digital subtraction angiography. Diagnostic performances of multiphasic computed tomography angiography findings-(1) a flame-shaped stump and (2) delayed contrast filling at the cervical ICA- were evaluated and compared. The Fisher exact test, χ2 test, or Wilcoxon rank-sum test and McNemar test were used in the data analysis. RESULTS: Twelve patients had true proximal ICA occlusion and 18 had pseudo-occlusion. Delayed contrast filling at the cervical ICA on multiphasic computed tomography angiography was found in all patients with pseudo-occlusion of the ICA, while 1 case of true occlusion showed delayed contrast filling (P<0.001). The presence of a flame-shaped stump was not significantly different between the pseudo- and true occlusion groups. The sensitivity of delayed contrast filling (0.94 [95% CI, 0.73-1]) was significantly higher than that of flame-shaped stump (0.75 [95% CI, 0.36-0.83]). CONCLUSIONS: We demonstrated that the delayed filling sign on multiphasic computed tomography angiography could be a useful and readily available finding for differentiating proximal ICA pseudo-occlusion from true occlusion.

MRI-visible dilated perivascular spaces in healthy young adults: A twin heritability study.

We investigated the narrow-sense heritability of MRI-visible dilated perivascular spaces (dPVS) in healthy young adult twins and nontwin siblings (138 monozygotic, 79 dizygotic twin pairs, and 133 nontwin sibling pairs; 28.7 ± 3.6 years) from the Human Connectome Project. dPVS volumes within basal ganglia (BGdPVS) and white matter (WMdPVS) were automatically calculated on three-dimensional T2-weighted MRI. In univariate analysis, heritability estimates of BGdPVS and WMdPVS after age and sex adjustment were 65.8% and 90.2%. In bivariate analysis, both BGdPVS and WMdPVS showed low to moderate genetic correlations (.30-.43) but high shared heritabilities (71.8-99.9%) with corresponding regional volumes, intracranial volumes, and other regional dPVS volumes. Older age was significantly associated with larger dPVS volume in both regions even after adjusting for clinical and volumetric variables, while blood pressure was not associated with dPVS volume although there was weak genetic correlation. dPVS volume, particularly WMdPVS, was highly heritable in healthy young adults, adding evidence of a substantial genetic contribution in dPVS development and differential effect by location. Age affects dPVS volume even in young adults, while blood pressure might have limited role in dPVS development in its normal range.

MRI and Quantitative Magnetic Susceptibility Maps of the Brain after Serial Administration of Gadobutrol: A Longitudinal Follow-up Study.

Background The relationship between administration of macrocyclic gadolinium-based contrast agents and T1-weighted signal intensity (SI) change of the globus pallidus (GP) and dentate nucleus (DN) is, to the knowledge of the authors, not known. Purpose To determine if quantitative susceptibility mapping (QSM) can detect changes in magnetic susceptibility of the GP and DN after serial administration of macrocyclic gadobutrol in patients with primary brain tumors. Materials and Methods Patients diagnosed with primary brain tumors from August 2014 to February 2019 were eligible for this single-center retrospective study. Among 501 consecutive adult patients who were given at least one administration of gadobutrol, those who were previously administered an unknown or linear gadolinium-based contrast agent were excluded. Brain MRI scans with three-dimensional gradient-recalled-echo image phase data for QSM processing were reviewed. Regions of interest were drawn on the GP and DN on the basis of semiautomatic thresholding. Univariable generalized estimation equations were used to determine the associations between MRI measures (SI on T1-weighted images and magnetic susceptibility on QSM) and number of gadobutrol doses. Potential confounding factors were adjusted for in multivariable generalized estimating equation. Results Ninety patients (mean age, 51 years ± 17 [standard deviation]; 51 men) with 199 MRI scans were analyzed. In models adjusted for repeated observations between injections, the number of injections of gadobutrol was associated with the magnetic susceptibility of the GP (1.4 × 10-3 ppm/number of gadobutrol injections; P = .01) and DN (8.1 × 10-4 ppm/number of gadobutrol injections; P = .03). After adjustment for confounders, the number of gadobutrol injections remained an independent predictor of increased magnetic susceptibility in the GP (1.3 × 10-3 ppm/number of gadobutrol injections; 95% confidence interval: 0.39 × 10-3, -2.4 × 10-3; P = .006). There were no associations between number of gadobutrol injections and SI or magnetic susceptibility in the DN. Conclusion The magnetic susceptibility of the globus pallidus increased after serial administration of gadobutrol. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Wang and Prince in this issue.

Dual-energy CT for differentiating acute intracranial hemorrhage from contrast staining or calcification: a meta-analysis.

PURPOSE: This study aimed to comprehensively evaluate the diagnostic performance of dual-energy CT (DECT) for differentiating acute intracranial hemorrhage (ICH) from contrast staining or small calcifications via a systematic review and meta-analysis. METHODS: The PubMed-MEDLINE, EMBASE, and Cochrane Library databases were searched up to November 10, 2019. Original studies (prospective or retrospective cohort studies) with the primary aim of detecting ICH using DECT were selected. The diagnostic performance of DECT was assessed using bivariate and hierarchical summary receiver operating characteristic models. Quality assessment was performed according to the Quality Assessment of Diagnostic Accuracy Studies-2, while between-study heterogeneity was assessed using Higgins' inconsistency index (I2). To explore heterogeneity, subgroup meta-regression analyses were performed. Deeks' funnel plot asymmetry test was used for assessing publication bias. RESULTS: Nine studies comprising 402 patients with 453 lesions were included for data synthesis. The overall pooled sensitivity and specificity of DECT for ICH detection were 96% (95% CI, 77-99%) and 98% (95 CI, 93%-100%), respectively. Substantial and moderate between-study heterogeneities were observed for sensitivity (I2 = 90.3%) and specificity (I2 = 57.9%), respectively. In meta-regression analysis, type of cohort affected heterogeneity-studies including only stroke patients showed lower sensitivity (43.5% vs. 94.2%) but higher specificity (98.7% vs. 92.6%) than those with mixed etiologies (P < 0.001). Deeks' funnel plot asymmetry test revealed publication bias (P = 0.020). CONCLUSION: DECT demonstrated excellent diagnostic performance in terms of differentiating acute ICH from contrast staining and small calcifications. However, publication bias suggests the possibility of overestimated diagnostic performance, warranting large-scale, prospective cohort studies.

CT-based quantitative evaluation of the efficacy after radiofrequency ablation in patients with benign thyroid nodules.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of CT for quantitative assessment of the neck structures after RFA in patients with benign thyroid nodules. MATERIALS AND METHODS: This single-center, retrospective cohort study included 38 patients with benign thyroid nodules who had received RFA and had available pre- and post-treatment CT images. Changes in the tracheal anteroposterior (AP)/transverse diameter ratio, cross-sectional tracheal area, midline deviation of the trachea, and anterior neck angle after RFA were quantitatively measured using CT. Volume reduction rates (VRRs) for the thyroid gland and nodules were measured using CT and US, respectively, and the intraclass correlation coefficient (ICC) was calculated. The paired Wilcoxon signed-rank test was used to compare pre- and post-treatment CT-based measurements, and univariate linear regression analysis was performed to determine the association of VRR with the mean delivered radiofrequency energy, number of RFA sessions, and initial thyroid volume. RESULTS: After RFA, the tracheal AP/transverse diameter ratio and midline deviation were significantly decreased while the tracheal area and anterior neck angle were significantly increased (all, p < 0.001). The thyroid volume reduction was also significant (VRR, 42.1% ± 21.1%, p < 0.001), with moderate consistency between the CT-based thyroid VRR and US-based nodule VRR (ICC = 0.68, 95% confidence interval = 0.38-0.83, p < 0.001). The mean delivered radiofrequency energy (p = 0.565), number of RFA sessions (p = 0.209), and initial thyroid volume (p = 0.363) showed no significant association with VRR. CONCLUSION: CT-based quantitative assessments may be useful for evaluating improvements in the neck structures after RFA for benign thyroid nodules.

Treatment outcomes of large and giant intracranial aneurysms according to various treatment modalities.

PURPOSE: This study aimed to compare the treatment outcomes of large (15-25 mm) and giant (> 25 mm) intracranial aneurysms (IAs), according to different treatment modalities. METHODS: In total, 112 patients with large and giant IAs treated with various treatment modalities between January 2009 and December 2018 were retrospectively reviewed. Clinical and radiological parameters were analyzed and correlated with the treatment modality. RESULTS: A total of 141 procedures were performed on 112 patients. We initially treated 47 cases with coil embolization, 39 with flow diverter (FD), 13 with direct clipping, and 13 with parent artery occlusion (PAO). Recurrence (46.8%) and retreatment (31.9%) rates were significantly higher in the coiling group (p < 0.001). Complete occlusion rate (36.3%) was significantly lower in the coiling group (p = 0.027). PAO could achieve a high complete occlusion rate (90.9%) with low complication rate (12.5%). The total complication rate was 17%. In the multivariate logistic regression analysis, FD (OR 3.406, p = 0.036) and direct clipping (OR 5.732, p = 0.017) showed a significantly higher complication rate than coiling. The overall mortality rate was 8% (8/139 procedures). At the last follow-up (mean 30.6 ± 26.4 months), 70 of 96 patients (72.9%) showed complete or near-complete occlusion. Good functional outcome (mRS ≤ 2) was observed in 90 of 112 (80.3%) patients at the last follow-up (mean 33.2 ± 30.5 months). CONCLUSIONS: Good clinical and radiologic outcomes with acceptable complication and mortality rates can be achieved by various treatment modalities. The selection of appropriate modality should be individualized based on the angiographic findings and clinical symptoms.

Comparison of efficacy and complications between radiofrequency ablation and repeat surgery in the treatment of locally recurrent thyroid cancers: a single-center propensity score matching study.

PURPOSE: To compare the efficacy and complication rates of radiofrequency ablation (RFA) and repeat surgery in the treatment of locally recurrent thyroid cancers. MATERIALS AND METHODS: A total of 221 patients with locally recurrent thyroid cancers who underwent either RFA (n = 96) or repeat surgery (n = 125) between March 2008 and March 2017 were retrospectively enrolled (range of follow-up, 1-10 years). Each cohort consisted of 70 patients after propensity score adjustment. Patients with more than three recurrent lesions were excluded. The primary and secondary end points were recurrence-free survival and complication rates, respectively. Recurrence-free survival curves were compared via the log-rank test. The complications-voice changes, hypocalcemia, and immediate procedural complications-were compared between the groups. In addition, pretreatment serum thyroglobulin (Tg) levels and those at the last follow-up were also compared between the two groups to examine therapeutic efficacy. RESULTS: After propensity score matching, both groups showed no significant differences in baseline characteristics. The recurrence-free survival rates were comparable between the RFA and surgery groups (p = .2). There were no significant differences in mean serum Tg levels and their mean decrease after treatment between the groups (p = .891 and p = .963, respectively). Immediate procedural complications and voice changes also showed no significant between-group differences (p = .316, p = .084, respectively). Hypocalcemia occurred only in the repeat surgery group (n = 18). Overall complications were significantly more frequent in the repeat surgery group (RFA, n = 7; surgery, n = 27; p < .001). CONCLUSION: RFA may be an effective and safe alternative to repeat surgery in the treatment of a small number of locally recurrent thyroid cancers.

Risk factors for recurrence and retreatment after endovascular treatment of intracranial saccular aneurysm larger than 8 mm.

BACKGROUND: Large intracranial aneurysm is challenging for both surgical and endovascular treatment. High recurrence and retreatment rates are still limitations for endovascular treatment. Analysing risk factors of recurrence after endovascular treatment can be useful for planning future treatment strategies. METHOD: We retrospectively reviewed patients with intracranial saccular aneurysm (≥ 8 mm) who underwent endovascular treatment from 2008 to 2017 at our institution. The demographic features, clinical information and angiographic results were analysed to reveal the risk factors for recurrence and retreatment. Subgroup analysis was performed according to packing density (PD) and stent insertion status. RESULTS: The total recurrence and retreatment rates were 25.7% (44/171) and 10.5% (18/171), respectively. Independent risk factors for recurrence after endovascular treatment were larger aneurysm size (OR 1.32; 95% CI 1.17-1.51; p < 0.001), ruptured status (OR 3.91; 95%CI 1.44-10.90; p = 0.008), initial incomplete occlusion (OR 2.72; 95%CI 1.18-6.41; p = 0.020), and low dome-to-neck ratio (OR 0.61; 95%CI 0.36-0.97; p = 0.047). The recurrence rate for the no-stent with low PD (< 17.5%) group was 50% (14/28); 37.5% (6/16) for stent-assisted coil (SAC) with low PD group, 22.0% (20/91) for no-stent with high PD group and 11.1% (4/36) for SAC with high PD group. CONCLUSION: The independent risk factors for recurrence after endovascular treatment in large (≥ 8 mm) intracranial saccular aneurysm were larger aneurysm size, ruptured status, low dome-to-neck ratio and initial incomplete occlusion state. SAC is a useful method for lowering recurrence after endovascular treatment for relatively large (≥ 8 mm) cerebral aneurysm.

Two-Dimensional WO3 Nanosheets Chemically Converted from Layered WS2 for High-Performance Electrochromic Devices.

Two-dimensional (2D) transitional metal oxides (TMOs) are an attractive class of materials due to the combined advantages of high active surface area, enhanced electrochemical properties, and stability. Among the 2D TMOs, 2D tungsten oxide (WO3) nanosheets possess great potential in electrochemical applications, particularly in electrochromic (EC) devices. However, feasible production of 2D WO3 nanosheets is challenging due to the innate 3D crystallographic structure of WO3. Here we report a novel solution-phase synthesis of 2D WO3 nanosheets through simple oxidation from 2D tungsten disulfide (WS2) nanosheets exfoliated from bulk WS2 powder. The complete conversion from WS2 into WO3 was confirmed through crystallographic and elemental analyses, followed by validation of the 2D WO3 nanosheets applied in the EC device. The EC device showed color modulation of 62.57% at 700 nm wavelength, which is 3.43 times higher than the value of the conventional device using bulk WO3 powder, while also showing enhancement of ∼46.62% and ∼62.71% in switching response-time (coloration and bleaching). The mechanism of enhancement was rationalized through comparative analysis based on the thickness of the WO3 components. In the future, 2D WO3 nanosheets could also be used for other promising applications such as sensors, catalysis, thermoelectric, and energy conversion.

Deep gray matter iron measurement in patients with liver cirrhosis using quantitative susceptibility mapping: Relationship with pallidal T1 hyperintensity.

BACKGROUND: The liver is a central organ for the metabolism of iron and manganese and the places where those metals are commonly deposited overlap in the brain. PURPOSE/HYPOTHESIS: To elucidate the relationship between pallidal T1 hyperintensity and iron deposition in the deep gray matter of liver cirrhosis patients using quantitative susceptibility mapping (QSM). STUDY TYPE: Retrospective case-control study SUBJECTS: In all, 38 consecutive liver cirrhosis patients who received brain magnetic resonance imaging (MRI) as pretransplant evaluation. FIELD STRENGTH/SEQUENCE: QSM was reconstructed from 3D multi- or single-echo phase images at 3T. T1 -weighted images were used for the assessment of pallidal hyperintensity and pallidal index (PI). ASSESSMENT: Patients were divided into two groups according to the presence of pallidal hyperintensity by consensus of two radiologists. Susceptibility values were acquired for five deep gray matter structures. STATISTICAL TEST: QSM measures were compared between two groups using the t-test. We also calculated Pearson correlations between QSM measures and PI. RESULTS: In all, 26 patients showed pallidal hyperintensity (T1 h group) and 12 did not (T1 n group). The susceptibility of the globus pallidus (GP) in the T1 h group (120.6 ± 38.1 ppb) was significantly lower than that in the T1 n group (150.0 ± 35.2, P = 0.030). The susceptibility of the dentate nucleus (DN) in the T1 h group (88.1 ± 31.0) was significantly lower than that in the T1 n group (125.6 ± 30.6, P = 0.001). Negative correlation between the susceptibility of GP (r = -0.37, P = 0.022) and the PI, and between DN (r = -0.43, P < 0.001) and the PI was found. DATA CONCLUSION: Liver cirrhosis patients with pallidal T1 hyperintensity had lower susceptibility values in the GP and DN than those without it. This suggests a possible interaction between iron and manganese in the brains of liver cirrhosis patients. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1342-1349.

Correlation-based perfusion mapping using time-resolved MR angiography: A feasibility study for patients with suspicions of steno-occlusive craniocervical arteries.

PURPOSE: To explore the feasibility of using correlation-based time-delay (CTD) maps produced from time-resolved MR angiography (TRMRA) to diagnose perfusion abnormalities in patients suspected to have steno-occlusive lesions in the craniocervical arteries. MATERIALS AND METHODS: Twenty-seven patients who were suspected to have steno-occlusive lesions in the craniocervical arteries underwent both TRMRA and brain single-photon emission computed tomography (SPECT). TRMRA was performed on the supra-aortic area after intravenous injection of a 0.03 mmol/kg gadolinium-based contrast agent. Time-to-peak (TTP) maps and CTD maps of the brain were automatically generated from TRMRA data, and their quality was assessed. Detection of perfusion abnormalities was compared between CTD maps and the time-series maximal intensity projection (MIP) images from TRMRA and TTP maps. Correlation coefficients between quantitative changes in SPECT and parametric maps for the abnormal perfusion areas were calculated. RESULTS: The CTD maps were of significantly superior quality than TTP maps (p < 0.01). For perfusion abnormality detection, CTD maps (kappa 0.84, 95% confidence interval [CI] 0.67-1.00) showed better agreement with SPECT than TTP maps (0.66, 0.46-0.85). For perfusion deficit detection, CTD maps showed higher accuracy (85.2%, 95% CI 66.3-95.8) than MIP images (66.7%, 46-83.5), with marginal significance (p = 0.07). In abnormal perfusion areas, correlation coefficients between SPECT and CTD (r = 0.74, 95% CI 0.34-0.91) were higher than those between SPECT and TTP (r = 0.66, 0.20-0.88). CONCLUSION: CTD maps generated from TRMRA were of high quality and offered good diagnostic performance for detecting perfusion abnormalities associated with steno-occlusive arterial lesions in the craniocervical area. KEY POINTS: • Generation of perfusion parametric maps from time-resolved MR angiography is clinically useful. • Correlation-based delay maps can be used to detect perfusion abnormalities associated with steno-occlusive craniocervical arteries. • Estimation of correlation-based delay is robust for low signal-to-noise 4D MR data.

Single-port laparoscopic surgery in uncomplicated acute appendicitis: a randomized controlled trial.

BACKGROUND: Single-port laparoscopic surgery (SPLS) is an alternative, minimally invasive surgical approach for managing appendicitis. The aim of this randomized trial was to evaluate the safety and efficacy of SPLS in uncomplicated appendicitis. METHODS: Between December 2009 and November 2010, 194 patients with radiologically diagnosed acute appendicitis were randomly allocated to undergo either SPLS or multiport laparoscopic surgery (MPLS). Patients with intraoperative findings of perforated appendicitis were excluded from the analysis. The primary endpoint was perioperative morbidity. All data were analyzed according to the intention-to-treat principle. RESULTS: Fourteen cases were excluded from the analysis. Of the remaining 180 patients, 90 were assigned to the SPLS group, and 90 to the MPLS group. Baseline characteristics were well balanced between the groups. In the SPLS group, the rate of conversion to MPLS was 11.1%. The operation time was 14.5 min longer for SPLS than for MPLS (p < 0.01), but there was no between-group difference in the rate of intraoperative complications (SPLS, 4.4%; MPLS, 0%; p = 0.12) or postoperative complications (SPLS, 4.4%; MPLS, 2.2%; p = 0.68). Compared to the MPLS group, the SPLS group had higher cumulative dose of analgesics (tramadol; 73.9 vs. 51.7 mg, p = 0.04), longer postoperative time to first passage of flatus (27.7 vs. 20.1 h, p < 0.01), longer postoperative hospitalization (2.5 vs. 2.1 days, p < 0.05), and higher total cost (1826.9 vs. 1662.4 USD, p < 0.01). CONCLUSIONS: This randomized trial indicates that, compared to MPLS, SPLS does not increase the rate of perioperative or postoperative complications in uncomplicated appendicitis, but may have disadvantages such as increased operation time, later postoperative functional recovery, longer hospital stay, and higher costs, although the difference is minimal (ClinicalTrials.gov Identifier: NCT01007318).

Classification of lung nodules in CT scans using three-dimensional deep convolutional neural networks with a checkpoint ensemble method.

BACKGROUND: Accurately detecting and examining lung nodules early is key in diagnosing lung cancers and thus one of the best ways to prevent lung cancer deaths. Radiologists spend countless hours detecting small spherical-shaped nodules in computed tomography (CT) images. In addition, even after detecting nodule candidates, a considerable amount of effort and time is required for them to determine whether they are real nodules. The aim of this paper is to introduce a high performance nodule classification method that uses three dimensional deep convolutional neural networks (DCNNs) and an ensemble method to distinguish nodules between non-nodules. METHODS: In this paper, we use a three dimensional deep convolutional neural network (3D DCNN) with shortcut connections and a 3D DCNN with dense connections for lung nodule classification. The shortcut connections and dense connections successfully alleviate the gradient vanishing problem by allowing the gradient to pass quickly and directly. Connections help deep structured networks to obtain general as well as distinctive features of lung nodules. Moreover, we increased the dimension of DCNNs from two to three to capture 3D features. Compared with shallow 3D CNNs used in previous studies, deep 3D CNNs more effectively capture the features of spherical-shaped nodules. In addition, we use an alternative ensemble method called the checkpoint ensemble method to boost performance. RESULTS: The performance of our nodule classification method is compared with that of the state-of-the-art methods which were used in the LUng Nodule Analysis 2016 Challenge. Our method achieves higher competition performance metric (CPM) scores than the state-of-the-art methods using deep learning. In the experimental setup ESB-ALL, the 3D DCNN with shortcut connections and the 3D DCNN with dense connections using the checkpoint ensemble method achieved the highest CPM score of 0.910. CONCLUSION: The result demonstrates that our method of using a 3D DCNN with shortcut connections, a 3D DCNN with dense connections, and the checkpoint ensemble method is effective for capturing 3D features of nodules and distinguishing nodules between non-nodules.

Linear sign in cystic brain lesions ≥5 mm: A suggestive feature of perivascular space.

OBJECTIVE: To determine the prevalence of a linear sign within enlarged perivascular space (EPVS) and chronic lacunar infarction (CLI) ≥ 5 mm on T2-weighted imaging (T2WI) and time-of-flight (TOF) magnetic resonance angiography (MRA), and to evaluate the diagnostic value of the linear signs for EPVS over CLI. METHODS: This study included 101 patients with cystic lesions ≥ 5 mm on brain MRI including TOF MRA. After classification of cystic lesions into EPVS or CLI, two readers assessed linear signs on T2WI and TOF MRA. We compared the prevalence and the diagnostic performance of linear signs. RESULTS: Among 46 EPVS and 51 CLI, 84 lesions (86.6%) were in basal ganglia. The prevalence of T2 and TOF linear signs was significantly higher in the EPVS than in the CLI (P < .001). For the diagnosis of EPVS, T2 and TOF linear signs showed high sensitivity (> 80%). TOF linear sign showed significantly higher specificity (100%) and accuracy (92.8% and 90.7%) than T2 linear sign (P < .001). CONCLUSIONS: T2 and TOF linear signs were more frequently observed in EPVS than CLI. They showed high sensitivity in differentiation of them, especially for basal ganglia. TOF sign showed higher specificity and accuracy than T2 sign. KEY POINTS: • Linear sign is a suggestive feature of EPVS. • Time-of-flight magnetic resonance angiography can reveal the lenticulostriate artery within perivascular spaces. • Linear sign helps differentiation of EPVS and CLI, especially in basal ganglia.