LI-RADS CT and MRI Ancillary Feature Association with Hepatocellular Carcinoma and Malignancy: An Individual Participant Data Meta-Analysis.

Background The independent contribution of each Liver Imaging Reporting and Data System (LI-RADS) CT or MRI ancillary feature (AF) has not been established. Purpose To evaluate the association of LI-RADS AFs with hepatocellular carcinoma (HCC) and malignancy while adjusting for LI-RADS major features through an individual participant data (IPD) meta-analysis. Materials and Methods Medline, Embase, Cochrane Central Register of Controlled Trials, and Scopus were searched from January 2014 to January 2022 for studies evaluating the diagnostic accuracy of CT and MRI for HCC using LI-RADS version 2014, 2017, or 2018. Using a one-step approach, IPD across studies were pooled. Adjusted odds ratios (ORs) and 95% CIs were derived from multivariable logistic regression models of each AF combined with major features except threshold growth (excluded because of infrequent reporting). Liver observation clustering was addressed at the study and participant levels through random intercepts. Risk of bias was assessed using a composite reference standard and Quality Assessment of Diagnostic Accuracy Studies 2. Results Twenty studies comprising 3091 observations (2456 adult participants; mean age, 59 years ± 11 [SD]; 1849 [75.3%] men) were included. In total, 89% (eight of nine) of AFs favoring malignancy were associated with malignancy and/or HCC, 80% (four of five) of AFs favoring HCC were associated with HCC, and 57% (four of seven) of AFs favoring benignity were negatively associated with HCC and/or malignancy. Nonenhancing capsule (OR = 3.50 [95% CI: 1.53, 8.01]) had the strongest association with HCC. Diffusion restriction (OR = 14.45 [95% CI: 9.82, 21.27]) and mild-moderate T2 hyperintensity (OR = 10.18 [95% CI: 7.17, 14.44]) had the strongest association with malignancy. The strongest negative associations with HCC were parallels blood pool enhancement (OR = 0.07 [95% CI: 0.01, 0.49]) and marked T2 hyperintensity (OR = 0.18 [95% CI: 0.07, 0.45]). Seventeen studies (85%) had a high risk of bias. Conclusion Most LI-RADS AFs were independently associated with HCC, malignancy, or benignity as intended when adjusting for major features. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Crivellaro in this issue.

Fully automated deep learning approach to dental development assessment in panoramic radiographs.

BACKGROUND: Dental development assessment is an important factor in dental age estimation and dental maturity evaluation. This study aimed to develop and evaluate the performance of an automated dental development staging system based on Demirjian's method using deep learning. METHODS: The study included 5133 anonymous panoramic radiographs obtained from the Department of Pediatric Dentistry database at Seoul National University Dental Hospital between 2020 and 2021. The proposed methodology involves a three-step procedure for dental staging: detection, segmentation, and classification. The panoramic data were randomly divided into training and validating sets (8:2), and YOLOv5, U-Net, and EfficientNet were trained and employed for each stage. The models' performance, along with the Grad-CAM analysis of EfficientNet, was evaluated. RESULTS: The mean average precision (mAP) was 0.995 for detection, and the segmentation achieved an accuracy of 0.978. The classification performance showed F1 scores of 69.23, 80.67, 84.97, and 90.81 for the Incisor, Canine, Premolar, and Molar models, respectively. In the Grad-CAM analysis, the classification model focused on the apical portion of the developing tooth, a crucial feature for staging according to Demirjian's method. CONCLUSIONS: These results indicate that the proposed deep learning approach for automated dental staging can serve as a supportive tool for dentists, facilitating rapid and objective dental age estimation and dental maturity evaluation.

Correlation between dental and skeletal maturity in Korean children based on dental maturity percentile: a retrospective study.

BACKGROUND: The correlation between dental maturity and skeletal maturity has been proposed, but its clinical application remains challenging. Moreover, the varying correlations observed in different studies indicate the necessity for research tailored to specific populations. AIM: To compare skeletal maturity in Korean children with advanced and delayed dental maturity using dental maturity percentile. DESIGN: Dental panoramic radiographs and cephalometric radiographs were obtained from 5133 and 395 healthy Korean children aged between 4 and 16 years old. Dental maturity was assessed with Demirjian's method, while skeletal maturity was assessed with the cervical vertebral maturation method. Standard percentile curves were developed through quantile regression. Advanced (93 boys and 110 girls) and delayed (92 boys and 100 girls) dental maturity groups were defined by the 50th percentile. RESULTS: The advanced group showed earlier skeletal maturity in multiple cervical stages (CS) in both boys (CS 1, 2, 3, 4, and 6) and girls (CS 1, 3, 4, 5, and 6). Significant differences, as determined by Mann-Whitney U tests, were observed in CS 1 for boys (p = 0.004) and in CS 4 for girls (p = 0.037). High Spearman correlation coefficients between dental maturity and cervical vertebral maturity exceeded 0.826 (p = 0.000) in all groups. CONCLUSION: A correlation between dental and skeletal maturity, as well as advanced skeletal maturity in the advanced dental maturity group, was observed. Using percentile curves to determine dental maturity may aid in assessing skeletal maturity, with potential applications in orthodontic diagnosis and treatment planning.

Individual Participant Data Meta-Analysis of LR-5 in LI-RADS Version 2018 versus Revised LI-RADS for Hepatocellular Carcinoma Diagnosis.

Background A simplification of the Liver Imaging Reporting and Data System (LI-RADS) version 2018 (v2018), revised LI-RADS (rLI-RADS), has been proposed for imaging-based diagnosis of hepatocellular carcinoma (HCC). Single-site data suggest that rLI-RADS category 5 (rLR-5) improves sensitivity while maintaining positive predictive value (PPV) of the LI-RADS v2018 category 5 (LR-5), which indicates definite HCC. Purpose To compare the diagnostic performance of LI-RADS v2018 and rLI-RADS in a multicenter data set of patients at risk for HCC by performing an individual patient data meta-analysis. Materials and Methods Multiple databases were searched for studies published from January 2014 to January 2022 that evaluated the diagnostic performance of any version of LI-RADS at CT or MRI for diagnosing HCC. An individual patient data meta-analysis method was applied to observations from the identified studies. Quality Assessment of Diagnostic Accuracy Studies version 2 was applied to determine study risk of bias. Observations were categorized according to major features and either LI-RADS v2018 or rLI-RADS assignments. Diagnostic accuracies of category 5 for each system were calculated using generalized linear mixed models and compared using the likelihood ratio test for sensitivity and the Wald test for PPV. Results Twenty-four studies, including 3840 patients and 4727 observations, were analyzed. The median observation size was 19 mm (IQR, 11-30 mm). rLR-5 showed higher sensitivity compared with LR-5 (70.6% [95% CI: 60.7, 78.9] vs 61.3% [95% CI: 45.9, 74.7]; P < .001), with similar PPV (90.7% vs 92.3%; P = .55). In studies with low risk of bias (n = 4; 1031 observations), rLR-5 also achieved a higher sensitivity than LR-5 (72.3% [95% CI: 63.9, 80.1] vs 66.9% [95% CI: 58.2, 74.5]; P = .02), with similar PPV (83.1% vs 88.7%; P = .47). Conclusion rLR-5 achieved a higher sensitivity for identifying HCC than LR-5 while maintaining a comparable PPV at 90% or more, matching the results presented in the original rLI-RADS study. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Sirlin and Chernyak in this issue.

Criteria for early diagnosis of mandibular third molar agenesis based on the developmental stages of mandibular canine, first and second premolars, and second molar: a retrospective cohort study.

BACKGROUND: Permanent first molars with severe dental caries, developmental defects, or involved in oral pathologies are at risk of poor prognosis in children. Accordingly, using the third molar to replace the first molar can be a good treatment option when third molar agenesis is predicted early. Thus, this retrospective cohort study aimed to develop criteria for early detection of mandibular third molar (L8) agenesis based on the developmental stages of mandibular canine (L3), first premolar (L4), second premolar (L5), and second molar (L7). METHOD: Overall, 1,044 and 919 panoramic radiographs of 343 males and 317 females, respectively, taken between the ages of 6 and 12 years were included. All developmental stages of L3, L4, L5, L7, and L8 were analyzed based on the dental age, as suggested by Demirjian et al. The independent t-test was used to assess age differences between males and females. The rank correlation coefficients were examined using Kendall's tau with bootstrap analysis and Bonferroni's correction to confirm the teeth showing developmental stages most similar to those of L8s. Finally, a survival analysis was performed to determine the criteria for the early diagnosis of mandibular third molar agenesis. RESULTS: Some age differences were found in dental developmental stages between males and females. Correlation coefficients between all stages of L3, L4, L5, and L7 and L8 were high. In particular, the correlation coefficient between L7 and L8 was the highest, whereas that between L3 and L8 was the lowest. CONCLUSION: If at least two of the following criteria (F stage of L3, F stage of L4, F stage of L5, and E stage of L7) are met in the absence of L8 crypt, agenesis of L8 can be confirmed.

CT/MRI and CEUS LI-RADS Major Features Association with Hepatocellular Carcinoma: Individual Patient Data Meta-Analysis.

Background The Liver Imaging Reporting and Data System (LI-RADS) assigns a risk category for hepatocellular carcinoma (HCC) to imaging observations. Establishing the contributions of major features can inform the diagnostic algorithm. Purpose To perform a systematic review and individual patient data meta-analysis to establish the probability of HCC for each LI-RADS major feature using CT/MRI and contrast-enhanced US (CEUS) LI-RADS in patients at high risk for HCC. Materials and Methods Multiple databases (MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and Scopus) were searched for studies from January 2014 to September 2019 that evaluated the accuracy of CT, MRI, and CEUS for HCC detection using LI-RADS (CT/MRI LI-RADS, versions 2014, 2017, and 2018; CEUS LI-RADS, versions 2016 and 2017). Data were centralized. Clustering was addressed at the study and patient levels using mixed models. Adjusted odds ratios (ORs) with 95% CIs were determined for each major feature using multivariable stepwise logistic regression. Risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) (PROSPERO protocol: CRD42020164486). Results A total of 32 studies were included, with 1170 CT observations, 3341 MRI observations, and 853 CEUS observations. At multivariable analysis of CT/MRI LI-RADS, all major features were associated with HCC, except threshold growth (OR, 1.6; 95% CI: 0.7, 3.6; P = .07). Nonperipheral washout (OR, 13.2; 95% CI: 9.0, 19.2; P = .01) and nonrim arterial phase hyperenhancement (APHE) (OR, 10.3; 95% CI: 6.7, 15.6; P = .01) had stronger associations with HCC than enhancing capsule (OR, 2.4; 95% CI: 1.7, 3.5; P = .03). On CEUS images, APHE (OR, 7.3; 95% CI: 4.6, 11.5; P = .01), late and mild washout (OR, 4.1; 95% CI: 2.6, 6.6; P = .01), and size of at least 20 mm (OR, 1.6; 95% CI: 1.04, 2.5; P = .04) were associated with HCC. Twenty-five studies (78%) had high risk of bias due to reporting ambiguity or study design flaws. Conclusion Most Liver Imaging Reporting and Data System major features had different independent associations with hepatocellular carcinoma; for CT/MRI, arterial phase hyperenhancement and washout had the strongest associations, whereas threshold growth had no association. © RSNA, 2021 Online supplemental material is available for this article.

Can Bone Erosion in Axial Spondyloarthropathy be Detected by Ultrashort Echo Time Imaging? A Comparison With Computed Tomography in the Sacroiliac Joint.

BACKGROUND: Structural lesion evaluation in axial spondyloarthropathy (SpA) can improve accuracy of diagnosis. However, structural lesions (bone erosions) are difficult to be assessed using conventional MRI compared to computed tomography (CT). PURPOSE: To evaluate the diagnostic performance of ultrashort echo time (UTE) for detecting bone erosion in axial SpA compared to T1WI and three-dimensional double-echo steady-state (3D DESS) imaging using CT as the reference standard. STUDY TYPE: Retrospective. POPULATION: Fourteen patients (eight females, 57.1%) and 14 healthy controls (seven females, 50.0%) who underwent sacroiliac (SI) joint MRI and CT. FIELD STRENGTH/SEQUENCE: 3 T; TSE T1WI, 3D DESS, 2D UTE. ASSESSMENT: The bilateral SI joints were assessed for bone erosion. Three observers scored bone erosion for all three sequences of MRI. CT was used as the gold standard. Diagnostic confidence in axial SpA was measured based on a four-point confidence score. STATISTICAL TESTS: Correlation of erosion scores between CT and MRI were evaluated using Spearman's correlation test. Sensitivity, specificity, and positive-negative predictive values were calculated. Confidence scores were compared using the Wilcoxon sum rank test. Statistical significance was set at P < 0.05. RESULTS: Compared with erosion scores of CT, the correlation coefficients for each MRI sequence showed significant low-to-high positive correlations (0.39-0.72). UTE imaging showed the highest correlation coefficients for all observers (0.70, 0.72, and 0.67, respectively). The specificity of UTE imaging was equal or higher than those of T1WI and 3D DESS for all observers (0.86 vs. 0.71 vs. 0.57; 0.93 vs. 0.71 vs. 0.57; 0.79 vs. 0.79 vs. 0.43). All observers had the highest confidence in interpreting UTE imaging for detecting bone erosion among the three sequences (3.5, 3.4, and 3.3 for UTE; 3.1, 3.0, and 2.6 for T1WI; and 3.2, 2.7, and 2.4 for DESS). DATA CONCLUSION: UTE imaging can detect bone erosions in patients with axial SpA and show higher specificity than conventional T1WI and 3D DESS. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 2.

Prevalence and correlation of OXIS contacts using Cone Beam Computed Tomography (CBCT) images and photographs.

BACKGROUND: The contact areas in between primary teeth are broader, flatter, and located further cervically when compared with the contact areas of permanent molars. AIM: We investigated the prevalence of interproximal contact area types of primary molars using CBCT images in children aged 3-10 years. Our second objective was to correlate OXIS contact areas when observed with CBCT images and clinical photographs. DESIGN: A retrospective cross-sectional study was performed with 367 CBCT images of children, aged 3-10 years, obtained from Children's Dental Centre, South Korea. The type of contacts in between primary molars was scored at various levels, specifically, occlusal, middle, and cervical thirds, according to OXIS criteria. Following this, the same patient's records were checked for the presence of clinical photographs and scored according to the same criteria. Prevalence was stated as percentages along with numbers. Chi-square test was applied to determine association of contact areas across genders and arches. The correlation between the two methods was done by Cohen's Kappa correlation test. RESULTS: The prevalence of the OXIS contacts obtained from CBCT images was as follows: I (79.7%), followed by X (10.0%), S (6.6%), and, finally, O (3.7%). The overall score of all the 1343 contact areas matched with the score observed at the occlusal third. All included contacts were of O (open) type at cervical third, and 1,231 contacts were of O (open) type at the middle third. Significant results were observed with respect to arches (P < .001). The correlation between the two methods was found to be 0.958. CONCLUSIONS: The contact area observed at the occlusal level determined the overall type of contact based on OXIS criteria. Thus, reports in the literature concluded that contact areas are broad, flat, and extend further gingivally should be revised. The study also concluded almost perfect agreement between CBCT images and clinical photographs.

Shear Bond Strength of Different MDP-Containing Adhesive Systems on Enamel and Dentin from Primary Teeth.

OBJECTIVE: To compare the shear bond strength (SBS) after thermocycling of four universal adhesives applied in self-etch mode on dentin and etch-and-rinse mode on enamel. STUDY DESIGN: Flat 144 buccal or lingual dentin and enamel surfaces from 72 non-carious primary molars were prepared. Samples were segregated into 12 groups (n=12): Adper Single Bond 2 etch-and-rinse (SB_T) and Clearfil SE Bond self-etch (SE_S) applied to enamel and dentin served as controls. Scotch Bond Universal Adhesive (SBU), Clearfil S3 Bond Universal Adhesive (SEU), Tetric N-Bond Universal Adhesive (TEN), and All Bond Universal (BIS) were applied in etch-and-rinse mode to enamel and in self-etch mode to dentin. They were thermocycled for 5000 cycles. SBS testing and the evaluation of fracture mode were performed. RESULTS: SB_T showed statistically higher SBS than other adhesive groups using etch-and-rinse mode on enamel. SE_S and BIS had statistically higher SBS than other adhesive groups using self-etch mode on dentin. Mixed failure was the most common failure mode in each group. CONCLUSION: The universal adhesives did not show higher SBS than SB_T when using etch-and-rinse on enamel. All universal adhesives showed higher SBS than SB_T and had SBS similar to SE_S, except SBU when using self-etch mode on dentin.

Dynamic contrast-enhanced and diffusion-weighted MRI of invasive breast cancer for the prediction of sentinel lymph node status.

BACKGROUND: Although sentinel lymph node biopsy (SLNB) is the current standard for identifying lymph metastasis in breast cancer patients, there are complications of SLNB. PURPOSE: To evaluate preoperative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) of invasive breast cancer for predicting sentinel lymph node metastasis. STUDY TYPE: Retrospective. POPULATION: In all, 309 patients who underwent clinically node-negative invasive breast cancer surgery FIELD STRENGTH/SEQUENCE: 3.0T, DCE-MRI, DWI. ASSESSMENT: We collected clinicopathologic variables (age, histologic and nuclear grade, extensive intraductal carcinoma component, lymphovascular invasion, and immunohistochemical profiles) and preoperative MRI features (tumor size, background parenchymal enhancement, internal enhancement, adjacent vessel sign, whole-breast vascularity, initial enhancement pattern, kinetic curve types, quantitative kinetic parameters, tumoral apparent diffusion coefficient [ADC], peritumoral maximal ADC, and peritumoral-tumoral ADC ratio). STATISTICAL TESTS: Multivariate logistic regressions were performed to determine independent variables associated with SLN metastasis, and the area under the receiver operating characteristic curve (AUC) was analyzed for those variables. RESULTS: 41 (13.3%) of the patients showed SLN metastasis. With MRI, tumor size (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.06-1.17), heterogeneous (OR, 5.33; 95% CI, 1.71-16.58), and rim (OR, 15.54; 95% CI, 2.12-113.72) enhancement and peritumoral-tumoral ADC ratio (OR, 72.79; 95% CI, 7.15-740.82) were independently associated with SLN metastasis. Clinicopathologic variables independently associated with SLN metastasis included age (OR, 0.96; 95% CI, 0.92-0.99) and CD31 (OR, 2.90; 95% CI, 1.04-8.92). The area under the curve (AUC) of MRI features (0.80; 95% CI, 0.73-0.87) was significantly higher than for clinicopathologic variables (0.68; 95% CI, 0.60-0.77; P = 0.048) and was barely below statistical significance for combined MRI features with clinicopathologic variables (0.84; 95% CI 0.78-0.90, P = 0.057). DATA CONCLUSION: Preoperative internal enhancement on DCE-MRI and peritumoral-tumoral ADC ratio on DWI might be useful for predicting SLN metastasis in patients with invasive breast cancer. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:615-626.

Staging of Liver Fibrosis by Means of Semiautomatic Measurement of Liver Surface Nodularity in MRI.

OBJECTIVE. The purposes of this study were to evaluate the accuracy of a semiautomatic method of measuring liver surface nodularity (LSN) on contrast-enhanced MR images and to compare the LSN score with pathologic fibrosis stage. MATERIALS AND METHODS. This retrospective study included patients who had undergone gadoxetate disodium-enhanced liver MRI 6 months before or after histopathologic investigation including percutaneous parenchymal biopsy and surgical biopsy for staging of chronic liver disease between January 2010 and December 2018. Semiautomated LSN quantification software was developed to measure LSN at MRI. Aspartate aminotransferase to platelet ratio index and fibrosis-4 index were derived from serum laboratory test results. The reference standard for staging of liver fibrosis was Metavir score. The accuracy of LSN score for staging of liver fibrosis was evaluated with AUC, and the optimal cutoff value was calculated by Youden index. Spearman correlation coefficient was used for correlation analysis. RESULTS. The study included 132 patients (93 men, 39 women). LSN score was evaluated without technical failure. There was high correlation between LSN score and Metavir score (Spearman ρ = 0.713, p < 0.001). The AUCs of LSN score for distinguishing Metavir score were 0.93 for F0-F1 versus F2-F4 (95% CI, 0.88-0.97; p < 0.001), 0.98 for F0-F2 vs F3-F4 (95% CI, 0.95-1.00; p < 0.001), and 0.83 for F0-F3 versus F4 (95% CI, 0.76-0.90; p < 0.001). The optimal cutoff value for differentiating F0-F2 from F3-F4 was 0.850 with 100% sensitivity and 85.4% specificity. CONCLUSION. LSN score calculated semiautomatically from MR images of the liver has high accuracy and correlates directly with the pathologic fibrosis stage.

Clinical Considerations for Dental Management of Children with Molar-Root Incisor Malformations.

Molar root-incisor malformation (MRIM) or molar-incisor malformation (MIM) is a new type of dental anomaly characterized by dysplastic roots of permanent first molars, occasionally second primary molars, and the crowns of maxillary central incisors. MRIM involving permanent first molars and second primary molars is characterized by normal crowns with short, thin, and narrow roots, whereas MRIM involving permanent maxillary central incisors exhibits constrictions of the crown in the cervical area. In the first case, we extracted the affected first permanent molars at the optimal timing to minimize space deficiencies and induce space closure. In addition, composite resin restorations were performed on the anterior central incisors. In the second case, a mandibular lingual arch was used to stabilize the affected teeth in order to mitigate discomfort by reducing rotational biting forces.

LI-RADS v2014 categorization of hepatocellular carcinoma: Intraindividual comparison between gadopentetate dimeglumine-enhanced MRI and gadoxetic acid-enhanced MRI.

OBJECTIVES: To use Liver Imaging Reporting and Data System (LI-RADS) categorization and features of hepatocellular carcinomas (HCCs) to intraindividually compare gadopentetate dimeglumine-enhanced magnetic resonance imaging (Gd-DTPA-MRI) and gadoxetic acid-enhanced MRI (Gd-EOB-MRI), before and after applying modified major features. METHODS: Of 77 HCCs in 64 patients analysed, 17 HCCs were confirmed histopathologically and 46 patients had cirrhosis. Gd-EOB-MRI and Gd-DTPA-MRI were evaluated for the presence of major and ancillary features by two radiologists. LI-RADS categorization was done for Gd-DTPA-MRI (LI-RADS-DTPA) and for Gd-EOB-MRI before and after applying modified major features (hepatobiliary phase [HBP] hypointensity as an additional major feature, LI-RADS-EOBm1; HBP hypointense rim as capsule appearance, LI-RADS-EOBm2; and transitional phase [TP] hypointensity as washout appearance, LI-RADS-EOBm3). Sensitivities of LR-5 categorization for the diagnosis of HCC were compared. RESULTS: Washout (p=0.012) and capsule appearance (p<0.001) were less frequently observed on Gd-EOB-MRI. Sensitivity for LR-5 categorization was significantly higher with LI-RADS-DTPA compared with LI-RADS-EOB (p=0.001) and LI-RADS-EOBm2 (p=0.004), while sensitivity for LR-5 categorization with LI-RADS-EOBm1 (p=0.210) and LI-RADS-EOBm3 (p=0.727) was comparable. CONCLUSION: Modifying LI-RADS for use with Gd-EOB-MRI, such as applying HBP hypointensity as an additional major feature or using TP hypointensity as washout appearance, can improve the sensitivity for the detection of HCC. KEY POINTS: • Adding HBP hypointensity as additional major feature improved sensitivity of LR-5 categorization. • Adding TP hypointensity as modified washout appearance improved sensitivity of LR-5 categorization. • Sensitivities for LR-5 classification were comparable between LI-RADS-DTPA, LI-RADS-EOBm1, and LI-RADS-EOBm3.

Linearity, Bias, and Precision of Hepatic Proton Density Fat Fraction Measurements by Using MR Imaging: A Meta-Analysis.

Purpose To determine the linearity, bias, and precision of hepatic proton density fat fraction (PDFF) measurements by using magnetic resonance (MR) imaging across different field strengths, imager manufacturers, and reconstruction methods. Materials and Methods This meta-analysis was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A systematic literature search identified studies that evaluated the linearity and/or bias of hepatic PDFF measurements by using MR imaging (hereafter, MR imaging-PDFF) against PDFF measurements by using colocalized MR spectroscopy (hereafter, MR spectroscopy-PDFF) or the precision of MR imaging-PDFF. The quality of each study was evaluated by using the Quality Assessment of Studies of Diagnostic Accuracy 2 tool. De-identified original data sets from the selected studies were pooled. Linearity was evaluated by using linear regression between MR imaging-PDFF and MR spectroscopy-PDFF measurements. Bias, defined as the mean difference between MR imaging-PDFF and MR spectroscopy-PDFF measurements, was evaluated by using Bland-Altman analysis. Precision, defined as the agreement between repeated MR imaging-PDFF measurements, was evaluated by using a linear mixed-effects model, with field strength, imager manufacturer, reconstruction method, and region of interest as random effects. Results Twenty-three studies (1679 participants) were selected for linearity and bias analyses and 11 studies (425 participants) were selected for precision analyses. MR imaging-PDFF was linear with MR spectroscopy-PDFF (R2 = 0.96). Regression slope (0.97; P < .001) and mean Bland-Altman bias (-0.13%; 95% limits of agreement: -3.95%, 3.40%) indicated minimal underestimation by using MR imaging-PDFF. MR imaging-PDFF was precise at the region-of-interest level, with repeatability and reproducibility coefficients of 2.99% and 4.12%, respectively. Field strength, imager manufacturer, and reconstruction method each had minimal effects on reproducibility. Conclusion MR imaging-PDFF has excellent linearity, bias, and precision across different field strengths, imager manufacturers, and reconstruction methods. © RSNA, 2017 Online supplemental material is available for this article. An earlier incorrect version of this article appeared online. This article was corrected on October 2, 2017.

Comparison of gradient-recalled echo and spin-echo echo-planar imaging MR elastography in staging liver fibrosis: a meta-analysis.

OBJECTIVES: To compare the diagnostic performance of gradient-recalled echo-based magnetic resonance elastography (GRE-MRE) and spin-echo echo-planar imaging-based MRE (SE-EPI-MRE) in liver fibrosis staging. METHODS: A systematic literature search was performed to identify studies involving the performance of MRE for the diagnosis of liver fibrosis. Pooled sensitivity, specificity, positive and negative likelihood ratios, the diagnostic odds ratio, and a summary receiver operating characteristic (ROC) curve were estimated by using a bivariate random effects model. Subgroup analyses were performed between different study characteristics. RESULTS: Twenty-six studies with a total of 3,200 patients were included in the meta-analysis. Pooled sensitivity and specificity of GRE-MRE and SE-EPI-MRE did not differ significantly. The area under the summary ROC curve for stage diagnosis of any (F ≥ 1), significant (F ≥ 2), advanced (F ≥ 3), and cirrhosis (F = 4) on GRE-MRE and SE-EPI-MRE were 0.93 versus 0.94, 0.95 versus 0.94, 0.94 versus 0.95, and 0.92 versus 0.93, respectively. Substantial heterogeneity was detected for both sequences. CONCLUSION: Both GRE and SE-EPI-MRE show high sensitivity and specificity for detection of each stage of liver fibrosis, without significant differences. Magnetic resonance elastography (MRE) may be useful for noninvasive evaluation of liver fibrosis in chronic liver disease. KEY POINTS: • Pooled sensitivity and specificity of GRE-MRE and SE-EPI-MRE did not differ significantly. • GRE-MRE and SE-EPI-MRE were highly accurate for detecting all stages of fibrosis. • Due to better agreement and repeatability, GRE-MRE should be used first. • In case of failure on GRE-MRE, SE-EPI-MRE should be used.

Comparison of transient severe motion in gadoxetate disodium and gadopentetate dimeglumine-enhanced MRI: effect of modified breath-holding method.

OBJECTIVES: To compare the occurrence of transient severe motion (TSM) between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI and between gadoxetate disodium-enhanced MRI scans obtained with and without the application of a modified breath-holding technique. METHODS: We reviewed 80 patients who underwent two magnetic resonance examinations (gadoxetate disodium-enhanced MRI and gadopentetate dimeglumine-enhanced MRI) with the application of a modified breath-holding technique (dual group). This group was compared with 100 patients who underwent gadoxetate disodium-enhanced MRI without the application of the modified breath-holding technique (single group). Patient risk factors and motion scores (1 [none] to 5 [non-diagnostic]) for each dynamic-phase imaging were analysed. RESULTS: In the dual group, mean motion scores did not differ significantly between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI (p=0.096-0.807) in any phase. However, in all phases except the late dynamic phase, mean motion scores of the dual group were significantly lower than those in the single group. TSM incidence did not differ significantly between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI in the dual group (3.8% vs. 1.3%, p=0.620). CONCLUSION: With proper application of the modified breath-holding technique, TSM occurrence with gadoxetate disodium-enhanced MRI was comparable to that associated with gadopentetate dimeglumine-enhanced MRI. KEY POINTS: • The modified breath-holding method significantly reduced the incidence of TSM. • Gadoxetate disodium and gadopentetate dimeglumine showed comparable motion scores. • TSM incidence was comparable between gadoxetate disodium- and gadopentetate dimeglumine-enhanced MRI.

Intra-individual comparison of hepatocellular carcinoma imaging features on contrast-enhanced computed tomography, gadopentetate dimeglumine-enhanced MRI, and gadoxetic acid-enhanced MRI.

Background Gadoxetic acid is being widely used for detection and characterization of hepatic nodules. However, there are no data regarding intra-individual comparison of imaging features of hepatocellular carcinoma (HCC) on dynamic computed tomography (CT), gadopentetate dimeglumine-enhanced magnetic resonance imaging (Gd-DTPA-MRI), and gadoxetic acid-enhanced MRI (Gd-EOB-MRI). Purpose To evaluate typical imaging features of HCC and capsule appearance with dynamic CT, Gd-DTPA-MRI, and Gd-EOB-MRI. Material and Methods We retrospectively reviewed 56 HCCs in 49 patients. Lesion attenuation/signal intensity was graded using a five-point scale based on dynamic phase and hepatobiliary phase (HBP) imaging. Subjective washout and capsule appearance were evaluated on portal venous phase (PVP) or delayed/transitional phase (DP/TP) imaging. The tumor-to-liver contrast ratio (TLCR) was calculated. Results Gd-DTPA-MRI and Gd-EOB-MRI was graded higher than CT on arterial phase ( P < 0.001). Gd-EOB-MRI was graded lower than Gd-DTPA-MRI on PVP and DP/TP ( P < 0.05). The detection rate of subjective washout and capsule appearance did not differ among the three imaging studies on either PVP or DP/TP. TLCR of Gd-EOB-MRI was lower than CT on PVP ( P = 0.004) and was lower than Gd-DTPA-MRI on DP/TP ( P = 0.001). Conclusion Arterial phase hyperenhancement and washout appearance of HCC were well demonstrated in Gd-EOB-MRI. The detection of capsule appearance using Gd-EOB-MRI was not inferior to Gd-DTPA-MRI or CT.

MK-0677, a Ghrelin Agonist, Alleviates Amyloid Beta-Related Pathology in 5XFAD Mice, an Animal Model of Alzheimer's Disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive deficits, neuroinflammation, and neuronal death. The primary pathogenic cause is believed to be the accumulation of pathogenic amyloid beta (Aß) assemblies in the brain. Ghrelin, which is a peptide hormone predominantly secreted from the stomach, is an endogenous ligand for the growth hormone secretagogue-receptor type 1a (GHS-R1a). MK-0677 is a ghrelin agonist that potently stimulates the GHS-R1a ghrelin receptor. Interestingly, previous studies have shown that ghrelin improves cognitive impairments and attenuates neuronal death and neuroinflammation in several neurological disorders. However, it is unknown whether MK-0677 can affect Aß accumulation or Aß-mediated pathology in the brains of patients with AD. Therefore, we examined the effects of MK-0677 administration on AD-related pathology in 5XFAD mice, an Aß-overexpressing transgenic mouse model of AD. MK-0677 was intraperitoneally administered to three-month-old 5XFAD mice. To visualize Aß accumulation, neuroinflammation, and neurodegeneration, thioflavin-S staining and immunostaining with antibodies against Aß (4G8), ionized calcium-binding adaptor molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), neuronal nuclear antigen (NeuN), and synaptophysin were conducted in the neocortex of 5XFAD and wild-type mice, and to evaluate changes of phosphorylated cyclic adenosine monophosphate (cAMP) response element binding protein (pCREB) levels, immunostaining with antibody against pCREB was performed in dentate gyrus of the hippocampus of 5XFAD and wild-type mice. The histological analyses indicated that MK-0677-treated 5XFAD mice showed reduced Aß deposition, gliosis, and neuronal and synaptic loss in the deep cortical layers, and inhibited the decrement of pCREB levels in dentate gyrus of the hippocampus compared to vehicle-treated 5XFAD mice. Our results showed that activation of the ghrelin receptor with MK-0677 inhibited the Aß burden, neuroinflammation, and neurodegeneration, which suggested that MK-0677 might have potential as a treatment of the early phase of AD.

Effects of dental treatment and systemic disease on oral health-related quality of life in Korean pediatric patients.

BACKGROUND: The findings that not only dental caries but also systemic disease can exert a negative effect on oral health-related quality of life (OHRQoL), and that dental treatment can improve OHRQoL have been confirmed in multiple studies. The purpose of this study is to investigate the impact of dental treatment on OHRQoL of Korean pediatric patients and the differences in OHRQoL between patients with and without systemic disease. METHODS: All the primary caregivers of pediatric patients who underwent dental treatments under either general anesthesia or intravenous deep sedation at Seoul National University Dental Hospital completed abbreviated versions of the Child Oral Health Impact Profile (COHIP-14) and Family Impact Scale (FIS-12) surveys on OHRQOL pre- and post-treatment (average: 2.4 ± 1.7 months after dental treatment). This is a case control study with patients divided into two groups according to the presence or absence of systemic disease. RESULTS: Data from 93 pediatric patients (46 male and 47 female, average patient age: 5.0 ± 3.4 years) were analyzed to compare OHRQoL before and after treatment with the Wilcoxon signed-rank test and to calculate the effect size using Cohen's d. All of the patients exhibited an improvement in OHRQoL (COHIP-14: p <  0.001, effect size = 1.0; FIS-12: p <  0.001, effect size = 0.7). Patients with systemic diseases demonstrated lower OHRQoL in both pre- and post-treatment surveys than patients without systemic diseases (Wilcoxon Rank-sum test, both COHIP-14 and FIS-12: p <  0.05). The COHIP-14 appears to have a greater impact on the FIS-12 in patients with systemic disease than those without (explanatory power of 65.3 and 44.6%, respectively). CONCLUSIONS: Based on the primary caregivers' perceptions, dental treatment can improve the OHRQoL in Korean pediatric patients. Systemic disease results in a reduced OHRQoL, and the awareness of patients' oral health appeared to have a greater impact on OHRQoL for family members of patients with a systemic disease. TRIAL REGISTRATION: KCT0002473 (Clinical Research Information Service, Republic of Korea) and 22 Sep 2017, retrospectively registered.