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This study aimed to investigate the efficacy and safety of using optimized parameters obtained by computer simulation for ultrasound-guided high-intensity focused ultrasound (HIFU) treatment of uterine adenomyosis in comparison with conventional parameters. We retrospectively assessed a single-institution, prospective study that was registered at Clinical Research Information Service (CRiS) of Republic of Korea (KCT0003586). Sixty-six female participants (median age: 44 years) with focal uterine adenomyosis were prospectively enrolled. All participants were treated with a HIFU system by using treatment parameters either for treating uterine fibroids (Group A, first 20 participants) or obtained via computer simulation (Group B, later 46 participants). To assess the treatment efficacy of HIFU, qualitative indices, including the clinically effective dysmenorrhea improvement index (DII), were evaluated up to 3 years after treatment, whereas quantitative indices, such as the nonperfused volume ratio and adenomyosis volume shrinkage ratio (AVSR), on MRI were evaluated up to 3 months after treatment. Quantitative/qualitative indices were compared between Groups A and B by using generalized linear mixed effect model. A safety assessment was also performed. Results showed that clinically effective DII was more frequently observed in Group B than in Group A (odds ratio, 3.69; P = 0.025), and AVSR were higher in Group B than in Group A (least-squares means, 21.61; P = 0.001). However, two participants in Group B developed skin burns at the buttock and sciatic nerve pain and required treatment. In conclusion, parameters obtained by computer simulation were more effective than the conventional parameters for treating uterine adenomyosis by using HIFU in terms of clinically effective DII and AVSR. However, care should be taken because of the risk of adverse events. [ABSTRACT FROM AUTHOR]

Purpose: Liver Imaging Reporting and Data System (LI-RADS) is limited by interreader variability. Thus, our study aimed to develop a deep-learning model for classifying LI-RADS major features using subtraction images using magnetic resonance imaging (MRI). Methods: This single-center retrospective study included 222 consecutive patients who underwent resection for hepatocellular carcinoma (HCC) between January, 2015 and December, 2017. Subtraction arterial, portal venous, and transitional phase images of preoperative gadoxetic acid-enhanced MRI were used to train and test the deep-learning models. Initially, a three-dimensional (3D) nnU-Net-based deep-learning model was developed for HCC segmentation. Subsequently, a 3D U-Net-based deep-learning model was developed to assess three LI-RADS major features (nonrim arterial phase hyperenhancement [APHE], nonperipheral washout, and enhancing capsule [EC]), utilizing the results determined by board-certified radiologists as reference standards. The HCC segmentation performance was assessed using the Dice similarity coefficient (DSC), sensitivity, and precision. The sensitivity, specificity, and accuracy of the deep-learning model for classifying LI-RADS major features were calculated. Results: The average DSC, sensitivity, and precision of our model for HCC segmentation were 0.884, 0.891, and 0.887, respectively, across all the phases. Our model demonstrated a sensitivity, specificity, and accuracy of 96.6% (28/29), 66.7% (4/6), and 91.4% (32/35), respectively, for nonrim APHE; 95.0% (19/20), 50.0% (4/8), and 82.1% (23/28), respectively, for nonperipheral washout; and 86.7% (26/30), 54.2% (13/24), and 72.2% (39/54) for EC, respectively. Conclusion: We developed an end-to-end deep-learning model that classifies the LI-RADS major features using subtraction MRI images. Our model exhibited satisfactory performance in classifying LI-RADS major features. [ABSTRACT FROM AUTHOR]

Purpose: Hepatobiliary phase (HBP) hypointense nodules without arterial phase hyperenhancement (APHE) on gadoxetic acid-enhanced MRI (GA-MRI) may be nonmalignant cirrhosis-associated nodules or hepatocellular carcinomas (HCCs). We aimed to characterize HBP hypointense nodules without APHE on GA-MRI by performing contrast-enhanced ultrasound using perfluorobutane (PFB-CEUS). Methods: In this prospective, single-center study, participants at high-risk of HCC having HBP hypointense nodules without APHE at GA-MRI were enrolled. All participants underwent PFB-CEUS; if APHE and late, mild washout or washout in the Kupffer phase were present, the diagnosis of HCC was established according to the v2022 Korean guidelines. The reference standard consisted of histopathology or imaging. The sensitivity, specificity, and positive/negative predictive values of PFB-CEUS for detecting HCC were calculated. Associations between clinical/imaging features and the diagnosis of HCC were evaluated with logistic regression analyses. Results: In total, 67 participants (age, 67.0 years ± 8.4; 56 men) with 67 HBP hypointense nodules without APHE (median size, 1.5 cm [range, 1.0–3.0 cm]) were included. The prevalence of HCC was 11.9% (8/67). The sensitivity, specificity, and positive and negative predictive values of PFB-CEUS for detecting HCC were 12.5%(1/8), 96.6%(57/59), 33.3%(1/3) and 89.1%(57/64), respectively. Mild-moderate T2 hyperintensity on GA-MRI (odds ratio, 5.756; P = 0.042) and washout in the Kupffer phase on PFB-CEUS (odds ratio, 5.828; P = 0.048) were independently associated with HCC. Conclusion: Among HBP hypointense nodules without APHE, PFB-CEUS was specific for detecting HCC, which had a low prevalence. Mild-moderate T2 hyperintensity on GA-MRI and washout in the Kupffer phase on PFB-CEUS may be useful to detect HCC in those nodules. [ABSTRACT FROM AUTHOR]

Objective: Low monoenergetic images obtained using noise-reduction techniques may reduce CT contrast media requirements. We aimed to investigate the effectiveness of low-contrast-dose CT using dual-energy CT and deep learning–based denoising (DLD) techniques in patients at high risk of hepatocellular carcinoma (HCC). Methods: We performed a prospective, randomized controlled noninferiority trial at a tertiary hospital between June 2019 and August 2020 (NCT04027556). Patients at high risk of HCC were randomly assigned (1:1) to the standard-contrast-dose group or low-contrast-dose group, which targeted a 40% reduction in contrast medium dose based on lean body weight. HCC conspicuity on arterial phase images was the primary endpoint with a noninferiority margin of 0.2. Images were independently assessed by three radiologists; model-based iterative reconstruction (MBIR) images of the standard-contrast-dose group and low monoenergetic (50-keV) DLD images of the low-contrast-dose group were compared using a generalized estimating equation. Results: Ninety participants (age 59 ± 10 years; 68 men) were analyzed. Compared with the standard-contrast-dose group (n = 47), 40% less contrast media was used in the low-contrast-dose group (n = 43) (107.0 ± 17.1 mL vs. 64.5 ± 11.3 mL, p < 0.001). In the arterial phase, HCC conspicuity on 50-keV DLD images in the low-contrast-dose group was noninferior to that of MBIR images in the standard-contrast-dose group (2.92 vs. 2.56; difference, 0.36; 95% confidence interval, −0.13 to ∞; p = 0.013). Conclusions: The contrast dose in liver CT can be reduced by 40% without impairing HCC conspicuity when using 50-keV and DLD techniques. Key Points: • In the arterial phase, hepatocellular carcinoma conspicuity on 50-keV deep learning–based denoising images in the low-contrast-dose group was noninferior to that of model-based iterative reconstruction images in the standard-contrast-dose group. • HCC detection was comparable between 50-keV deep learning–based denoising images in the low-contrast-dose group and model-based iterative reconstruction images in the standard-contrast-dose group. [ABSTRACT FROM AUTHOR]

Background: Complete resection is the only potentially curative treatment in patients with pancreatic ductal adenocarcinoma (PDA) and is associated with a longer overall survival (OS) than incomplete resection of tumor. Hence, prediction of the resection status after surgery would help predict the prognosis of patients with PDA. Purpose: To predict residual tumor (R) classification and OS in patients who underwent first-line surgery for PDA using preoperative magnetic resonance imaging (MRI). Material and Methods: In this study, 210 patients with PDA who underwent MRI and first-line surgery were randomly categorized into a test group (n=150) and a validation group (n=60). The R classification was divided into R0 (no residual tumor) and R1/R2 (microscopic/macroscopic residual tumor). Preoperative MRI findings associated with R classification and OS were assessed by using logistic regression and Cox proportional hazard models. In addition, the prediction models for the R classification and OS were validated using calibration plots and C statistics. Results: On preoperative MRI, portal vein encasement (odds ratio 4.755) was an independent predictor for R1/R2 resection (P =0.040). Tumor size measured on MRI (hazard ratio [HR] per centimeter 1.539) was a predictor of OS, along with pathologic N1 and N2 stage (HR 1.944 and 3.243, respectively), R1/R2 resection (HR 3.273), and adjuvant chemoradiation therapy (HR 0.250) (P <0.050). Calibration plots demonstrated satisfactory predictive performance. Conclusion: Preoperative MRI was valuable for predicting R1/R2 resection using portal vein encasement. Tumor size measured on MRI was useful for the prediction of OS after first-line surgery for PDA. [ABSTRACT FROM AUTHOR]

Background: Stratification of patients who undergo curative resection for early gastric cancer (EGC) is warranted due to the heterogeneity in the risk of developing extragastric recurrence (EGR). Therefore, we aimed to stratify the need for postoperative surveillance for EGR detection in patients with EGC by developing a model for predicting EGR-free survival. Methods: This retrospective cohort study included patients who underwent postoperative surveillance after curative resection of EGC (n = 4149). Cox proportional hazard models were used to identify predictors to build a model for predicting EGR-free survival. Bootstrap-corrected c-index and calibration plots were used for internal and external (n = 2148) validations. Results: A risk-scoring system was constructed using variables significantly associated with EGR-free survival: pathologic T stage (pT1b[sm1], hazard ratio [HR] 4.928; pT1b[sm2], HR 5.235; pT1b[sm3], HR 7.748) and N stage (pN1, HR 4.056; pN2, HR 9.075; pN3, HR 30.659). Patients were dichotomized into a very-low-risk group or a low-or-greater-risk group. The 5-year EGR-free survival rates differed between the two groups (99.9 vs. 97.3%). The discriminative performance of the model was 0.851 (Uno's c-index) and 0.751 in the internal and external cohorts, respectively. The calibration slope was 0.916 and 1.131 in the internal and external cohorts, respectively. Conclusions: Our model for predicting EGR-free survival based on the pathologic T and N stages may be useful for stratifying patients who have undergone curative surgery for EGC. The results suggest that patients in the very-low-risk group may be spared from postoperative surveillance considering their extremely high EGR-free survival rate. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) positron emission tomography/magnetic resonance imaging (PET/MRI) can improve the diagnostic performance of TNM staging and help in making an accurate decision regarding resectability in patients with recurrent gastric cancer compared to multi-detector computed tomography (MDCT). Methods: Fifty patients with histologically (n = 31) or clinically (n = 19) confirmed recurrent gastric cancer underwent both MDCT and [18F]FDG PET/MRI. Two radiologists independently assessed TNM staging using MDCT with and without [18F]FDG PET/MRI and scored resectability using a 5-point confidence scale. Diagnostic performance as assessed by radiologists was compared using McNemar's test and receiver operating characteristic curve analysis. Results: Of the 50 patients, pathologic T and N staging was available in seven and six patients, respectively. Diagnostic accuracies for T and N staging were not significantly different between MDCT with and without [18F]FDG PET/MRI for both reviewers (p > 0.05). However, for M staging, diagnostic accuracy was significantly improved when 18F-FDG PET/MRI was added to MDCT alone (68.0% [34/50] to 90.0% [45/50] for reviewer 1 [p = 0.001] and 66.0% [33/50] to 96.0% [46/50] for reviewer 2 [p < 0.001]). Regarding the resectability of recurrent gastric cancers, the addition of [18F]FDG PET/MRI increased the area under the curve values for both reviewers (from 0.860 to 0.989 for reviewer 1 and from 0.778 to 0.898 for reviewer 2), with a statistical significance for reviewer 2 (p = 0.002). Conclusion: Compared to MDCT alone, MDCT plus [18F]FDG PET/MRI can improve the diagnostic accuracy for evaluating preoperative M staging as well as resectability for recurrent gastric cancers. Key Points: • [18F]FDG PET/MRI can improve diagnostic accuracy for preoperative M staging in patients with recurrent gastric cancers. • [18F]FDG PET/MRI can improve diagnostic accuracy for determining resectability in patients with recurrent gastric cancers. • [18F]FDG PET/MRI can provide critical clues for management options for recurrent gastric cancers. [ABSTRACT FROM AUTHOR]

Objectives: Patients with hepatocellular carcinoma (HCC) receiving different treatments might have specific prognostic factors that can be captured in the hepatobiliary phase (HBP) of gadoxetic acid-enhanced magnetic resonance imaging (GA-MRI). We aimed to identify the clinical findings and HBP features with prognostic value in patients with HCC.Methods: In this retrospective, single-institution study, we included patients with Barcelona Clinic Liver Cancer very early/early stage HCC who underwent GA-MRI before treatment. After performing propensity score matching, 183 patients received the following treatments: resection, radiofrequency ablation (RFA), and transarterial chemoembolization (TACE) (n = 61 for each). Cox regression models were used to identify clinical factors and HBP features associated with disease-free survival (DFS) and overall survival (OS).Results: In the resection group, large tumor size was associated with poor DFS (hazard ratio [HR] 4.159 per centimeter; 95% confidence interval [CI], 1.669-10.365) and poor OS (HR 8.498 per centimeter; 95% CI, 1.072-67.338). In the RFA group, satellite nodules on HBP images were associated with poor DFS (HR 5.037; 95% CI, 1.061-23.903) and poor OS (HR 9.398; 95% CI, 1.480-59.668). Peritumoral hypointensity on HBP images was also associated with poor OS (HR 13.062; 95% CI, 1.627-104.840). In addition, serum albumin levels and the prothrombin time-international normalized ratio were associated with DFS and/or OS. Finally, in the TACE group, no variables were associated with DFS/OS.Conclusions: Different HBP features and clinical factors were associated with DFS/OS among patients with HCC receiving different treatments.Key Points: • In patients who underwent resection for HCC, a large tumor size on HBP images was associated with poor disease-free survival and overall survival. • In the RFA group, satellite nodules and peritumoral hypointensity on HBP images, along with decreased serum albumin levels and PT-INR, were associated with poor disease-free survival and/or overall survival. • In the TACE group, no clinical or HBP imaging features were associated with disease-free survival or overall survival. [ABSTRACT FROM AUTHOR]

Objectives: Post-hepatectomy liver failure (PHLF) can occur as a major complication after hepatic resection (HR) in patients with hepatocellular carcinoma (HCC) and negatively affects the prognosis. We aimed to retrospectively assess whether the spleen volume (SV) measured from preoperative CT images would be associated with the development of PHLF and overall survival (OS) after HR in patients with HCC. Methods: We enrolled 317 consecutive patients with very early/early stage HCC who underwent a preoperative CT and HR between January 2010 and December 2016. The SV was obtained from preoperative CT images using semi-automated volumetric software and was divided by body surface area to yield SVBSA. Receiver operating characteristic (ROC) curves and logistic regression analyses were performed to identify factors affecting the development of PHLF. The Cox proportional hazard model was used to identify prognostic factors for OS. Results: PHLF was observed in 72 patients (22.7% [72/317]). SVBSA was associated with the development of PHLF (odds ratio, 2.321; 95% CI, 1.347–4.001; p = 0.002) with the area under the ROC curve of 0.663 using the cutoff value of 107.5 cm3 (p < 0.001). SVBSA was also an influencing factor for OS (hazard ratio, 3.935; 95% CI 1.520–10.184; p = 0.005), with the optimal cutoff of 146 cm3. The 5-year OS rate was higher in 245 patients with a SVBSA ≤ 146 cm3 than in 72 patients with a SVBSA > 146 cm3 (95.0% vs. 78.7%, p < 0.001). Conclusions: In patients with HCC, a larger SVBSA was associated with a higher rate of PHLF and worse OS after HR. The SVBSA may be useful in selecting good surgical candidates. Key Points: • A significantly higher spleen volume divided by body surface area was observed in patients who experienced post-hepatectomy liver failure than in patients who did not (148 cm3vs. 112 cm3, p < 0.001). • The area under the receiver operating characteristic curve of spleen volume divided by body surface area to predict the development of post-hepatectomy liver failure was 0.663 (p < 0.001). • Spleen volume divided by body surface area was a significant influencing factor for overall survival (hazard ratio, 3.935; 95% CI, 1.520–10.184; p < 0.001), with the optimal cutoff of 146 cm3. [ABSTRACT FROM AUTHOR]

Objectives: To identify MRI features that are helpful for the differentiation of gallbladder neuroendocrine tumors (GB-NETs) from gallbladder adenocarcinomas (GB-ADCs) and to evaluate their prognostic values.Methods: Between January 2008 and December 2018, we retrospectively enrolled patients who underwent MRI for GB malignancy. Two radiologists independently assessed the MRI findings and reached a consensus. Significant MRI features, which distinguish GB-NETs from GB-ADCs, were identified. Cox regression analyses were performed to find MRI features that were prognostic for overall survival.Results: There were 63 patients with GB-NETs (n = 21) and GB-ADCs (n = 42). Compared with GB-ADCs, GB-NETs more frequently demonstrated the following MRI features: well-defined margins, intact overlying mucosa, and thick rim contrast enhancement and/or diffusion restriction (ps < 0.001). Liver metastases were more common and demonstrated thick rim contrast enhancement and diffusion restriction in GB-NETs (ps < 0.001). Lymph node (LN) metastasis showed thick rim diffusion restriction more often in GB-NETs than in GB-ADCs (p = 0.009). On quantitative analysis, the sizes of the GB mass and metastatic LNs in GB-NETs were larger than those in GB-ADCs (p = 0.002 and p = 0.010, respectively). The ratio of apparent diffusion coefficient values between the lesion and the spleen was lower in the GB mass, liver metastases, and LN metastases of GB-NETs than those of GB-ADCs (p < 0.001, p = 0.017, and p < 0.001, respectively). Survival analysis revealed that a large metastatic LN (hazard ratio 1.737; 95% confidence interval, 1.112-2.712) was the only poor prognostic factor (p = 0.015).Conclusion: Several MRI features aided in differentiating between GB-NETs and GB-ADCs. A large metastatic LN was associated with poor survival.Key Points: • Compared with gallbladder adenocarcinomas (GB-ADCs), neuroendocrine tumors (GB-NETs) and their metastases to the liver and lymph nodes more frequently demonstrated a thick rim appearance on contrast-enhanced MRI and diffusion-weighted images. • The ratio of apparent diffusion coefficient values between the lesion and the spleen was significantly lower for the primary mass, liver metastases, and lymph node metastases of GB-NETs than for those of GB-ADCs. • A large metastatic lymph node was the only poor prognostic factor for overall survival in patients with GB-NETs and GB-ADCs. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the diagnostic performance of attenuation imaging (ATI) in the detection of hepatic steatosis compared with a histopathology gold standard.Methods: We prospectively enrolled 108 consecutive patients (35 males; median age, 54.0 years) who underwent percutaneous liver biopsy for evaluation of diffuse liver disease between January 2018 and November 2018 in a tertiary academic center. Grayscale ultrasound examination with ATI was performed just before biopsy, and an attenuation coefficient (AC) was obtained from each patient. The degree of hepatic steatosis, fibrosis stage, and necroinflammatory activity were assessed on histopathologic examination. The significant factor associated with the AC was found by a linear regression analysis, and the diagnostic performance of the AC for the classification into each hepatic steatosis stage was evaluated by receiver operating characteristic (ROC) analysis.Results: The distribution of hepatic steatosis grade on histopathology was 53/11/22/16/6 for none/mild (< 10%)/mild (≥ 10%)/moderate/severe steatosis, respectively. The area under the ROC curve, sensitivity, specificity, and optimal cutoff AC value for detection of hepatic steatosis ranged from 0.843-0.926, 74.5-100.0%, 77.4-82.8%, and 0.635-0.745, respectively. Multivariate analysis revealed that the degree of steatosis was the only significant determinant factor for the AC.Conclusions: The AC from ATI provided good diagnostic performance in detecting the varying degrees of hepatic steatosis. The degree of steatosis was the only significant factor affecting the AC, whereas fibrosis and inflammation were not.Key Points: • Attenuation imaging (ATI) is based on two-dimensional grayscale ultrasound images that can incorporate into routine ultrasound examinations with less than 2 min of acquisition time. • ATI provided good diagnostic performance in detecting the varying degrees of hepatic steatosis with an area under the ROC curves ranging from 0.843 to 0.926, and there was no technical failure in this study indicating high applicability of this technique. • The degree of hepatic steatosis was the only significant factor affecting the result of ATI examination. [ABSTRACT FROM AUTHOR]

Objectives: This study was conducted in order to determine the prognostic value of MRI for extramural venous invasion (EMVI) in rectal cancer compared to pathology and to assess the diagnostic performance of multireaders.Methods: We retrospectively enrolled 222 patients (M:F = 148:74; mean age ± standard deviation, 61.5 ± 12 years) with histopathologically proven rectal cancers who underwent preoperative MRI between 2007 and 2016. Among them, 74 patients had positive EMVI on pathology (pEMVI) and 148 patients had negative pEMVI. Three radiologists with 7 (reviewer 1), 3 (reviewer 2), and 1 (reviewer 3) year of experience in rectal MR imaging determined the presence of EMVI on MRI (mrEMVI) using a 5-point grading system. Using histopathologic results as the reference standard, radiologists' performances were analyzed and compared with receiver operating characteristic (ROC) analysis. For assessment of interobserver variation, intraclass correlation coefficients (ICC) were used. Lastly, Kaplan-Meier estimation and Cox proportional hazard models were used for survival analysis.Results: The area under the ROC curve (AUC) was highest in reviewer 1 (0.829), followed by reviewer 2 (0.798) and reviewer 3 (0.658). Differences in AUCs between reviewer 1 or 2 and reviewer 3 were statistically significant (p < 0.001). ICC was substantial between reviewers 1 and 2. Overall survival (OS) was significantly different according to the positive circumferential resection margin, adjuvant treatment, and the presence of mrEMVI, but not by the presence of pEMVI.Conclusions: For experienced radiologists, the diagnostic performance of mrEMVI was good, resulting in better prediction of OS than with pEMVI, with substantial interobserver agreement.Key Points: • When read by experienced radiologists, MR can provide reliable diagnostic performance in assessing EMVI for patients with rectal cancer. • Positive mrEMVI is an adverse prognostic factor of overall survival and may influence the clinical decision-making. [ABSTRACT FROM AUTHOR]

• AC on ATI significantly correlated with HFF on 1H-MRS (ρ = 0.674, P < 0.001). • ATI well detected significant fatty liver among potential liver donors (AUC = 0.923). • ATI showed a high NPV of 97.2% (95% confidence interval = 90.3–99.2%), for detecting significant fatty liver. In living donor liver transplantation (LDLT), fatty liver adversely affects the outcome in donors or in recipients. The attenuation imaging (ATI) may be valuable for detecting fatty liver in potential liver donors. We aimed to investigate the role of ATI in screening liver donors. In this prospective study, potential liver donors undergoing MR examination, including proton MR spectroscopy (1H-MRS), were enrolled between January 2020 and December 2021 (study identifier: KCT0004486). All participants underwent ATI examinations to assess fatty liver disease. The reference standard for fatty liver was the hepatic fat fraction (HFF) on 1H-MRS, with 8% defined as the threshold for significant fatty liver. The correlation between attenuation coefficient (AC) and HFF was evaluated using Spearman's correlation coefficient. The diagnostic performance of AC for the detection of fatty liver disease was evaluated using receiver operating characteristic curve analysis. A total of 102 participants (median age, 37 [range, 20–61] years; 65 men) were enrolled. Nineteen participants (18.6%) had significant fatty liver on 1H-MRS. AC significantly correlated with HFF on 1H-MRS (ρ = 0.674, P < 0.001), and was significantly higher in patients with HFF on 1H-MRS ≥ 8% than in patients with HFF on 1H-MRS < 8% (0.76 vs. 0.59, P < 0.001). By using the cutoff value of 0.66, the area under the curve of AC for the detection of significant fatty liver on 1H-MRS was 0.923 (95% confidence interval [CI]: 0.853–0.967), with sensitivity, specificity, and negative predictive values of 89.5% (95% CI: 66.9–98.7%), 83.1% (95% CI: 73.3–90.5%), and 97.2% (95% CI: 90.3–99.2%), respectively. ATI showed good diagnostic performance with a high negative predictive value for the detection of significant fatty liver among potential liver donors. [ABSTRACT FROM AUTHOR]

Objectives: To predict residual tumor (R) classification and overall survival (OS) on preoperative MDCT in patients who underwent first-line surgery for pancreatic ductal adenocarcinoma (PDA).Methods: Three hundred sixteen patients with PDA who underwent MDCT and first-line surgery were included. Patients were divided into a test (n = 216) and a validation group (n = 100). The R classification was categorized into R0 (no residual tumor) and R1/R2 (microscopic/macroscopic residual tumor). We assessed the correlation between the MDCT findings and the R classification. For survival analysis, we used the Kaplan-Meier estimation and Cox proportional hazard model to determine the prognostic factors for OS. Validation of the prediction models for the R classification and OS was performed using C statistics and calibration plot.Results: Peritumoral fat stranding (odds ratio (OR) 3.826), suspicious distant metastasis (OR 2.916), portal vein involvement (OR 2.795), and tumor size (OR 1.045) were independent predictors for residual tumor (p < .05). On survival analysis, common hepatic artery involvement (hazard ratio (HR) 5.656), R1/R2 stage (HR 2.476), and N1 stage (HR 1.745) were predictors of poor OS (p < .05). C statistics for prediction models for R classification and OS were 0.816 and 0.662, respectively. Calibration plots showed good predictive performance in a high probability of the R1/R2 stage or poor OS.Conclusion: Preoperative MDCT is useful for predicting the R classification using the tumor size, peritumoral fat stranding, portal vein involvement, and suspicious distant metastasis, as well as for anticipating poor OS using the N1 stage, common hepatic artery involvement, and R1/R2 stage in patients with PDA.Key Points: • Thorough assessment of the involvement of common hepatic artery or portal vein and peritumoral fat stranding is warranted for predicting prognosis in patients with pancreatic ductal adenocarcinoma. • Not only encasement but also abutment of common hepatic artery or portal vein by tumor predicts poor prognosis after upfront surgery. • If residual tumor or poor overall survival is anticipated on preoperative MDCT, neoadjuvant treatment can be performed. [ABSTRACT FROM AUTHOR]

Objectives: To differentiate between large (≥ 1 cm in diameter) gallbladder (GB) non-neoplastic and neoplastic polyps using quantitative analysis of contrast-enhanced ultrasound (CEUS) findings.Methods: From September 2017 to May 2018, 29 patients (10 males; median age, 63 years) with GB polyps of ≥ 1 cm in diameter who were undergoing cholecystectomy were consecutively enrolled. All patients underwent preoperative conventional US and CEUS examinations. Quantitative analysis of CEUS findings using time-intensity curves between the two groups was independently performed by two radiologists. The interobserver agreement for the quantitative analysis of the CEUS results was measured using the intraclass correlation coefficient. Receiver operating characteristic analysis was performed to evaluate the diagnostic performance of CEUS examination.Results: After the cholecystectomy, the patients were classified into the non-neoplastic polyp group (n = 12) and the neoplastic polyp group (n = 17) according to the pathological results. The interobserver agreement for quantitative assessment between the two radiologists was near perfect to substantial. Quantitative assessment of the CEUS findings revealed that the rise time, mean transit time, time to peak, and fall time of non-neoplastic GB polyps were significantly shorter than those of neoplastic polyps (p < 0.001, p = 0.008, p = 0.013, and p = 0.002, respectively). The sensitivity and specificity of the quantitative CEUS parameters for the differentiation between the two groups were 76.5-100% and 75%, respectively, with an area under the curve of 0.765-0.887.Conclusions: Quantitative analysis of CEUS findings could be valuable in differentiating GB neoplastic polyps from non-neoplastic polyps.Key Points: • Quantitative analysis of CEUS findings could be valuable in differentiating gallbladder neoplastic polyps from non-neoplastic polyps. • Quantitative analysis of CEUS findings in gallbladder polyps provides cut-off values for differentiation between neoplastic polyps and non-neoplastic polyps with near-perfect to substantial interobserver agreement. [ABSTRACT FROM AUTHOR]

Objectives: To compare the virtual non-contrast (VNC) images acquired through dual-energy computed tomography (DECT) with the true non-contrast (TNC) images in the detection of biliary stones and to calculate dose reduction by replacing TNC images with VNC images.Methods: Between March 2017 and April 2018, we retrospectively enrolled 75 patients with suspicious biliary disease who underwent dual-source DECT and surgery and/or endoscopic intervention within 2 months from the CT. Biliary stones were present in 45 patients. The sensitivity and specificity for detecting gallstone and common bile duct (CBD) stone were compared between the VNC and TNC using McNemar test. In addition, the possible reduction in radiation dose was calculated.Results: In our study, 37 patients had gallstones, 2 had CBD stones, and 6 had both gallstone and CBD stones. For detection of gallstones, the sensitivity and specificity were 90.7% (39/43) and 87.5% (28/32), respectively, for the TNC images, and 88.4% (38/43) and 90.6% (29/32), respectively, for the VNC images. With respect to CBD stones, the sensitivity and specificity were 87.5% (7/8) and 98.5% (66/67), respectively, for the TNC images, and 75.0% (6/8) and 100% (67/67), respectively, for the VNC images. There was no significant difference in the sensitivity and specificity between each image set (P > 0.05). The radiation dose reduction of 22.4 ± 1.3% is expected by omitting TNC images.Conclusions: The VNC images derived from DECT were comparable to the TNC images for the detection of biliary stones and may replace the TNC images to reduce radiation dose. [ABSTRACT FROM AUTHOR]

Purpose: To determine the normal liver stiffness values using magnetic resonance elastography (MRE) at 3.0 T and to compare spin-echo echo-planar imaging (SE-EPI) and gradient-recalled-echo (GRE) MRE.Materials and Methods: This retrospective study included 54 living liver donors who had normal clinical and pathological results without underlying liver disease and underwent MRE using both SE-EPI and GRE at 3.0 T. Two radiologists placed four or six freehand regions of interest (ROI) on the elastograms and measured liver stiffness as well as the area of ROIs. The mean liver stiffness values and area of ROIs were compared between genders, among age groups, and between groups of different body mass indexes using the t-test and one-way analysis of variance, respectively. Interobserver agreement was analyzed using intraclass correlation coefficient. The mean liver stiffness values and area of ROIs were compared between SE-EPI and GRE using the paired t-test and Bland-Altman analysis.Results: The liver stiffness values in living liver donors ranged from 1.52 to 3.12 kPa on SE-EPI and 1.51 to 2.67 kPa on GRE. The mean liver stiffness values did not differ significantly according to the gender, age, and body mass index. Measurement of liver stiffness using MRE showed excellent interobserver agreement on both pulse sequences. The mean value of liver stiffness was higher on SE-EPI (2.14 ± 0.33 kPa) than on GRE (2.06 ± 0.25 kPa), and the difference was statistically significant (P < 0.05). The mean area of ROI was significantly larger with GRE (3387 mm2) than with SE-EPI (2691 mm2) (P < 0.05).Conclusions: The mean liver stiffness values in living donors measured by SE-EPI and GRE were not affected by gender, age, or body mass index and showed excellent interobserver agreement. The area of ROI was larger with GRE than with SE-EPI. [ABSTRACT FROM AUTHOR]

Purpose To validate usefulness of magnetic resonance (MR) lymphangiography for evaluation of peripheral lymphedema in upper extremities by comparison with lymphoscintigraphy. Materials and methods This prospective study had institutional review board approval and written informed consent was obtained from all patients. Initially, protocol of MR lymphangiography for upper extremity was established in seven healthy volunteers with 3.0T fat-saturated three-dimensional gradient-echo MR after gadobutrol injection. Then six patients with unilateral lymphedema of the upper extremities were examined with MR lymphangiography and lymphoscintigraphy, and the results were correlated with each other. Four categories were defined to scale the quality of drainage. Results of both techniques were separately evaluated by two radiologists and a nuclear physician. We evaluated sensitivity, specificity and correlation of both techniques. Results MR lymphangiography showed sensitivities of 100% for all four categories, while lymphoscintigraphy yielded a sensitivity of 83.3% for delineation of lymph vessels and 100% for the other three categories. Specificity of MR lymphangiography was 85.7% for delay of drainage and 100% for other three categories, while lymphoscintigraphy showed specificity of 66.7% for pattern of lymphatic drainage and 100% for other three categories. Delay and pattern of drainage was same in 83.3% and non-visualization of axillary LNs was indistinguishably noted in all patients on both techniques. Anatomic level of enhanced lymph vessel was identical in 66.7% of the patients. Conclusion MR lymphangiography showed better performance for depiction of lymph vessels. MR lymphangiography and lymphoscintigraphy yielded same results in all or most patients for evaluation of axillary lymph nodes enhancement and lymphatic drainage in upper extremity. [ABSTRACT FROM AUTHOR]

Background & aims: To assess diagnostic accuracy of gadoxetic acid–enhanced MR for small hypervascular hepatocellular carcinoma (HCC) detected by C-arm CT and concordance rate of Liver Imaging Reporting and Data System (LI-RADS). Methods: In this retrospective study, we recruited 4,544 patients suspected of having HCC underwent C-arm CT from November 2008 to May 2013. Among these patients, gadoxetic acid–enhanced MR was performed in 167 patients with HCC (n = 379; 257 > 1 cm, 122 ≤ 1 cm). HCC was confirmed by MR, CT, or follow-up images. Two radiologists graded likelihood of HCC and assessed MR features. Jackknife alternative free-response receiver operating characteristic (JAFROC) analysis was performed. All HCCs were evaluated concordance rate of LI-RADS. Results: Mean JAFROC figure of merit for large (>1-cm) HCC was 0.948, while that for small HCC was 0.787 with fair agreement (κ = 0.409). Mean sensitivity and positive predictive value (PPV) were 91% and 90% for large HCC versus 63.0% and 79% for small HCC, respectively. Seventeen of 122 small HCCs (13.9%) were not visible on MR. Among 379 HCCs, 99 met LR-5, and 259 met LR-4. Common features for small HCC included arterial enhancement (81.9%), hepatobiliary phase hypointensity (80.3%), and delayed washout (72.9%). Conclusion: Diagnostic accuracy of gadoxetic acid–enhanced MR imaging for small, hypervascular HCCs (Mean figure of merit = 0.787) was still low compared with large HCC (Mean figure of merit = 0.948). LR-5 and LR-4 covered 94% (358/379) of the HCCs. [ABSTRACT FROM AUTHOR]

Purpose: We retrospectively investigated the feasibility and clinical efficacy of balloon dilatation and subsequent retrievable stent insertion, when necessitated, for pyloric spasms after pylorus-preserving gastrectomy (PPG). Materials and Methods: Forty-five patients experiencing pyloric spasms after PPG underwent fluoroscopic balloon dilations to alleviate obstructive symptoms due to delayed gastric emptying. Patients showing poor response to balloon dilation underwent subsequent retrievable stent insertion. Safety of the procedures was analyzed, and subjective symptoms and objective signs of pyloric spasms were analyzed and compared before and after treatment. Results: Thirty-three patients (73.3%, 33/45) showed good response to balloon dilatation requiring no further treatment (balloon group). Conversely, 12 patients (26.7%, 12/45) showed poor or no response after balloon dilation requiring subsequent stent insertion (stent group). Balloon dilations and/or stent insertions were safely performed in all patients except one patient who suffered a transmural tear after balloon dilatation. In both groups, mean subjective symptom score was significantly improved and mean pyloric canal-to-height of the adjacent vertebral body ratio was significantly increased after the procedures (P <.05). Conclusion: Balloon dilation is a safe and effective treatment for patients with pyloric spasms after PPG. In patients refractory to balloon dilations, retrievable stent placement can be a safe alternative tool. [ABSTRACT FROM AUTHOR]

Bae, J.S., Kim, H.J., Choi, J., 2013. Surface Roller Effect Affecting on Shear Fluctuations of a SandyDuck Experiment under a Random Wave Environment. Surface roller effect affecting on shear fluctuations of a SandyDuck experiment was investigated under a random wave environment by using the combination of SHORECIRC and SWAN. The surface roller, which is a strong turbulent region of waves that break and tumble shoreward, has been known to be significant for modelling of nearshore wave-induced motions. The surface roller forces to move the maximum of the cross-shore profile of the mean longshore current toward the shore, and it increases longshore current velocity in the sandbar trough region. Consequently its effect improves the predictions of mean nearshore circulations and surface elevation. The surface roller effect, which gives the corrections to surfzone dynamics, plays a significant role on the shear fluctuations of longshore current. In this study, shear fluctuation changes depending on the surface roller effect were numerically analyzed. As a result, since the surface roller effect moves the maximum of the cross-shore profile of the mean longshore current toward the shore, the location of shear fluctuations was moved toward the shore. And the surface roller effect suppressed rapid rip currents or separation of vortices due to shear fluctuation out of the surfzone, and decreased its fluctuation energy. [ABSTRACT FROM AUTHOR]

Bae, J.S., Yoon, S.B., Choi, J., 2013. Boussinesq Modelling of a Rip Current at Haeundae Beach. The rip current occurring at Haeundae beach in Busan, South Korea was numerically investigated under directional random wave environment. The numerical simulations were performed using a fully nonlinear Boussinesq equation model, FUNWAVE which is capable of resolving phase interaction and simulating nearshore circulation since it includes the effect of wave-induced momentum flux and horizontal turbulent mixing. To examine the modelling, the rip current occurred on the 12th of June, 2011 at Haeundae beach was simulated by using observations. The results of numerical simulation showed the time-dependent evolution of the wave-induced nearshore circulation that was caused by transformation of random waves due to the unique topography of Haeundae beach. And, it was found that the rip current was well generated and developed through the region where relatively lower wave heights were caused by refraction and diffraction of waves due to the topographical characteristics (i.e., submerged shoal). In addition, we found that a narrow-banded spectral wave (i.e., a swell spectrum) close to a regular wave generates stronger rip current than a broad-banded spectral wave under an equivalent wave height and period condition. [ABSTRACT FROM AUTHOR]

Objectives: To determine the appropriate use of ancillary features (AFs) in upgrading LI-RADS category 3 (LR-3) to category 4 (LR-4) for hepatic nodules on gadoxetic acid–enhanced MRI. Methods: We retrospectively analyzed MRI features of solid hepatic nodules (≤ 30 mm) categorized as LR-3/4 on gadoxetic acid–enhanced MRI. In LI-RADS diagnostic table-based-LR-3 observations, logistic regression analyses were performed to identify AFs suggestive of hepatocellular carcinomas (HCCs) rather than non-malignant nodules. Using McNemar's test, the sensitivities and specificities of the final-LR-4 category for HCC diagnosis were compared according to the principles of AF application in category adjustment. Results: A total of 336 hepatic nodules (191 HCCs; 145 non-malignant) in 252 patients were evaluated. Based on major HCC features, 248 nodules (123 HCCs) were assigned as table-based-LR-3 and 88 nodules (68 HCCs) as table-based-LR-4. In table-based-LR-3 observations, mild–moderate T2 hyperintensity was identified as an independent predictor of HCC as opposed to non-malignant nodules (odds ratio = 3.01, p = 0.002). For HCC diagnosis, different criteria of final-LR-4: only table-based-LR-4, allowing category upgrade using only T2 hyperintensity, or using any AFs favoring malignancy resulted in sensitivities of 35.6% (68/191), 53.9% (103/191), and 88.5% (169/191), and specificities of 86.2% (125/145), 75.9% (110/145), and 21.4% (31/145), respectively, which differed from each other (all p < 0.001). Conclusions: While the application of MRI AF in LI-RADS category adjustment increases the sensitivity of LR-4 category for HCC diagnosis, it is accompanied by a significant decrease in specificity. Mild–moderate T2 hyperintensity, a significant AF indicative of HCC, may be more appropriate for upgrading LR-3 to LR-4. Key Points: • When upgrading from LR-3 to LR-4 using any MRI ancillary features favoring malignancy, LR-4 sensitivity increases but specificity decreased for HCC diagnosis. • By upgrading LR-3 to LR-4 based on MRI ancillary features found to suggest HCC rather than non-malignant nodules in multivariate analysis (i.e., mild–moderate T2 hyperintensity), LR-4 demonstrated a more balanced sensitivity and specificity for HCC diagnosis (53.9% and 75.9%, respectively). [ABSTRACT FROM AUTHOR]

Purpose: To predict poor overall survival (OS) and risk of residual tumor after surgery using MR imaging, clinical, and histopathological findings in perihilar cholangiocarcinoma. Methods: 196 patients with perihilar cholangiocarcinoma who underwent preoperative MRI and curative-intent surgery were retrospectively included. MRI findings were assessed by two radiologists. Clinical characteristics and histopathological results such as serum carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9), T and N stage, and resection status, were also investigated. Cox regression analysis and the Kaplan–Meier method were used to identify prognostic factors for OS. We further analyzed the correlation between MRI features and residual tumors using logistic regression analysis. Results: The median OS was 25.0 ± 26.6 months. T stage (hazard ratio [HR] 6.26, p = 0.014), N stage (HR 1.86, p = 0.002), CA-19-9 >37 U/mL (HR 2.06, p < 0.001), enlarged LN on MRI (HR 1.69, p = 0.006), and residual tumor (HR 1.52, p = 0.034) were important predictors of poor survival. The 5-year OS of the complete resection group (n = 107) was significantly better than that of the residual tumor group (n = 89) (35.5% vs. 18.8%, p = 0.002). Additionally, peritumoral fat stranding (odds ratio[OR] 2.09, p = 0.027), Bismuth type III/IV (OR 1.95, p = 0.022), and common bile duct (CBD) involvement (OR 2.3, p = 0.008) on MRI were important predictors of residual tumors in univariate analyses. However, absence of peritumoral fat stranding was a significant independent predictor for complete resection (OR 1.99, p = 0.048) and showed the highest sensitivity, at 79.8%. Conclusion: MR imaging, clinical and histopathological results are useful for predicting poor survival after surgery for perihilar cholangiocarcinoma. Furthermore, MRI findings, including peritumoral fat stranding, CBD involvement, and Bismuth type, are important for the prediction of residual tumors. [ABSTRACT FROM AUTHOR]

Objectives: Both transient elastography (TE) and 2D shear wave elastography (SWE) are accurate methods to evaluate liver fibrosis. We aimed to evaluate the diagnostic performance of 2D-SWE in predicting post-hepatectomy complication and to compare it with TE. Methods: We prospectively enrolled 125 patients with liver tumors. Liver stiffness (LS) (kilopascal [kPa]) was measured using both TE and 2D-SWE before surgery. All post-operative complication was evaluated using the comprehensive complication index (CCI), and CCI ≥ 26.2 was defined as severe complication. Logistic regression analysis was performed to identify predictive factors for severe complication. Receiver operating characteristic analysis was used to evaluate the diagnostic performance of TE/2D-SWE in detecting liver fibrosis and severe complication. Results: Severe complication developed in 18 patients. The median LS in patients with severe complication was significantly higher for both 2D-SWE (11.4 kPa vs. 7.0 kPa, p < 0.001) and TE (8.9 kPa vs. 6.2 kPa, p = 0.009). LS obtained from 2D-SWE was a significant factor correlated with severe complication (odds ratio: 1.27 per kPa [1.10–1.46], p = 0.001). The diagnostic performance of 2D-SWE was significantly higher than that of TE in detecting both ≥F3 (p = 0.024) and F4 (p = 0.048). The area under the curve of 2D-SWE to predict severe complication was 0.854, significantly higher than 0.692 of TE (p = 0.004). The optimal cut-off LS from 2D-SWE to predict severe complication was 8.6 kPa, with sensitivity of 88.9% (16/18) and specificity of 73.8% (79/107). Conclusion: LS obtained from 2D-SWE was a significant predictive factor for severe complication, and 2D-SWE showed significantly a better diagnostic performance than TE in detecting liver fibrosis and severe complication. Key Points: • The diagnostic performance of 2D-SWE was significantly higher than that of TE in detecting both ≥ F3 (AUC: 0.853 vs. 0.779, p = 0.024) and F4 (AUC: 0.929 vs. 0.872, p = 0.048). • Liver stiffness value obtained from 2D-SWE was a significant factor correlated with the development of severe complication defined as CCI ≥ 26.2 after hepatic resection for liver tumors (odds ratio: 1.27 per kPa [1.10–1.46], p = 0.001). • 2D-SWE provided significantly a better diagnostic performance in predicting severe complication after hepatic resection than TE (AUC for 2D-SWE: 0.853 vs. AUC for TE: 0.692, p = 0.004). [ABSTRACT FROM AUTHOR]

There are still lot of controversies whether aberrant left hepatic artery (ALHA) originating from left gastric artery should be ligated or preserved during gastric cancer (GC) surgery. We aimed to investigate this issue. We reviewed ALHA cases who had laparoscopic gastrectomy for gastric cancer at Seoul National University Hospital (SNUH) from 2012 to 2016. Type of ALHA variants using Michel's classification of hepatic arterial anatomy and diameter of each vessel were evaluated by 2 radiologists. Postoperative hepatic function and surgical outcome were collected until 6 months after surgery. Results showed that if the diameter of ALHA was larger than 1.5 mm, a transient elevation of SGOT and SGPT on postoperative day 2 was observed in the ligated cases. No differences were observed in operation time, amount of blood loss, overall complication rate, hospital stay, and number of lymph nodes retrieved between the ligated and preserved replaced left hepatic artery (RLHA) and accessory left hepatic artery (acLHA) group. In this study, we conclude that ligation of ALHA seems to be safe as none of the patients suffered adverse outcome. A transient rise in postoperative SGOT and SGPT levels were seen after ligating ALHA >1.5 mm in diameter regardless of subtype. [ABSTRACT FROM AUTHOR]

Although acid suppressants are needed to attenuate gastrointestinal bleeding (GIB) after percutaneous coronary intervention (PCI), pharmacodynamic interaction between clopidogrel and proton pump inhibitor (PPI) can increase the risk of high platelet reactivity (HPR). We sought to evaluate serial changes of platelet measures and influence of rabeprazole on platelet measures. After 600-mg clopidogrel loading for elective PCI, clopidogrel-sensitive patients were recruited and randomly assigned to add rabeprazole of daily 20 mg (n = 40) or famotidine of daily 40 mg (n = 40). Platelet measures were performed with light transmittance aggregometry and VASP-P assay. Primary endpoint was 5 μM ADP-induced platelet aggregation (PA) at 30-day follow-up. HPR was defined as 5 μM ADP-induced PA > 46%. Baseline platelet measures did not differ significantly between the groups. The 30-day level of 5 μM ADP-induced PA was similar between the famotidine vs. rabeprazole group (30.0 ± 16.4% vs. 30.2 ± 13.9%, P=.956). In addition, other platelet measures were comparable between the groups. At 30-day follow-up, the incidence of HPR was similar between the famotidine and rabeprazole groups (20.5% vs. 15.4%; P=.555). In conclusion, adjunctive use of rabeprazole showed the similar antiplatelet effect even in clopidogrel-sensitive patients compared with adjunctive famotidine, which may support the similar effect of rabeprazole and famotidine on the antiplatelet effect of dual antiplatelet therapy with clopidogrel plus aspirin. [ABSTRACT FROM AUTHOR]

The aim of the work described here was to evaluate the diagnostic performance of perfluorobutane (PFB)-enhanced ultrasound in differentiating hepatocellular carcinoma (HCC) from non-HCC malignancies and other benign lesions using different acquisition methods. This prospective study included 69 patients with solid liver lesions larger than 1 cm who were scheduled for biopsy or radiofrequency ablation between September 2020 and March 2021. Lesion diagnosis was designated by three blinded radiologists after reviewing three different sets of acquired images selected according to the following presumed acquisition methods: (i) method A, acquisition up to 5 min after contrast injection; (ii) method B, acquisition up to 1 min after contrast injection with additional Kupffer phase; and (iii) method C, acquisition up to 5 min after contrast injection with additional Kupffer phase. After excluding 7 technical failures, 62 patients with liver lesions (mean size: 24.2 ± 14.8 mm), which consisted of 7 benign lesions, 37 non-HCC malignancies and 18 HCCs. For the HCC diagnosis, method C had the highest sensitivity (75.9%), followed by method B (72.2%) and method A (68.5%), but failed to exhibit statistical significance (p = 0.12). There was no significant difference with respect to the pooled specificity between the three methods (p = 0.28). Diagnostic accuracy was the highest with method C (87.1%) but failed to exhibit statistical significance (p = 0.24). Image acquisition up to 5 min after contrast injection with additional Kupffer phase could potentially result in high accuracy and sensitivity without loss of specificity in diagnosing HCC with PFB-enhanced ultrasound. [ABSTRACT FROM AUTHOR]

Objectives: To determine the correlation between iodine concentrations derived from dual-energy CT (DECT) and perfusion CT (PCT) parameters in patients with pathologically proven colorectal cancers (CRC) and to evaluate their reproducibility and respective radiation exposures.Methods: Institutional review board approval and written informed consents were obtained for this study. Forty-one patients with CRCs who underwent same-day DECT and PCT were prospectively enrolled. Three radiologists independently analyzed the iodine concentration of the tumors and iodine ratios [ratio of lesion to aorta (IRa) or to infrarenal IVC (IRv)] from DECT as well as blood flow (BF), blood volume (BV), permeability (PMB), and mean transit time (MTT) from PCT. Pearson R and linear correlation, paired t-test, and intraclass correlation coefficients (ICCs) were used.Results: Significant correlations were found between iodine parameters from DECT and PCT parameters: iodine concentration of tumors and BV (r = 0.32, p = 0.04), PMB (r = 0.34, p = 0.03), and MTT (r = -0.38, p = 0.02); iodine ratio (IRa) and MTT (r = -0.32, p = 0.04); iodine ratio (IRv) and BF (r = 0.32, p = 0.04) and PMB (r = 0.44, p = <0.01). DECT showed better intra- and interobserver agreements (ICC = 0.98, 0.90 in iodine concentration; 0.98, 0.91 in IRa; and 0.91, 0.93 in IRv, respectively) than PCT (ICC = 0.90, 0.78 in BF; 0.82, 0.76 in BV; 0.75, 0.75 in PMB; 0.64, 0.79 in MTT, respectively). As for radiation dosage, CTDIvol and DLP in DECT (10.48 ± 1.84 mGy and 519.7 ± 116.7 mGy·cm) were significantly lower than those of PCT (75.76 mGy and 911 mGy·cm) (p < 0.01).Conclusion: Iodine parameters from DECT are significantly correlated with PCT parameters, but have higher intra- and interobserver agreements and lower radiation exposure.Key Points: • Quantitative iodine concentrations from DECT are significantly correlated with perfusion CT parameters. • Intra- and interobserver agreements of DECT are better than those of perfusion CT. • Effective radiation doses of DECT are significantly lower than those of perfusion CT. • DECT can be used as an alternative to perfusion CT with lower radiation doses. [ABSTRACT FROM AUTHOR]

Objective: To investigate the image quality and lesion conspicuity of a deep-learning-based contrast-boosting (DL-CB) algorithm on double-low-dose (DLD) CT of simultaneous reduction of radiation and contrast doses in participants at high-risk for hepatocellular carcinoma (HCC). Methods: Participants were recruited and underwent four-phase dynamic CT (NCT04722120). They were randomly assigned to either standard-dose (SD) or DLD protocol. All CT images were initially reconstructed using iterative reconstruction, and the images of the DLD protocol were further processed using the DL-CB algorithm (DLD-DL). The primary endpoint was the contrast-to-noise ratio (CNR), the secondary endpoint was qualitative image quality (noise, hepatic lesion, and vessel conspicuity), and the tertiary endpoint was lesion detection rate. The t-test or repeated measures analysis of variance was used for analysis. Results: Sixty-eight participants with 57 focal liver lesions were enrolled (20 with HCC and 37 with benign findings). The DLD protocol had a 19.8% lower radiation dose (DLP, 855.1 ± 254.8 mGy·cm vs. 713.3 ± 94.6 mGy·cm, p =.003) and 27% lower contrast dose (106.9 ± 15.0 mL vs. 77.9 ± 9.4 mL, p <.001) than the SD protocol. The comparative analysis demonstrated that CNR (p <.001) and portal vein conspicuity (p =.002) were significantly higher in the DLD-DL than in the SD protocol. There was no significant difference in lesion detection rate for all lesions (82.7% vs. 73.3%, p =.140) and HCCs (75.7% vs. 70.4%, p =.644) between the SD protocol and DLD-DL. Conclusions: DL-CB on double-low-dose CT provided improved CNR of the aorta and portal vein without significant impairment of the detection rate of HCC compared to the standard-dose acquisition, even in participants at high risk for HCC. Key Points: • Deep-learning-based contrast-boosting algorithm on double-low-dose CT provided an improved contrast-to-noise ratio compared to standard-dose CT. • The detection rate of focal liver lesions was not significantly differed between standard-dose CT and a deep-learning-based contrast-boosting algorithm on double-low-dose CT. • Double-low-dose CT without a deep-learning algorithm presented lower CNR and worse image quality. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the diagnostic value of deep learning model (DLM) reconstructed dual-energy CT (DECT) low-keV virtual monoenergetic imaging (VMI) for assessing hypoenhancing hepatic metastases. Methods: This retrospective study included 131 patients who underwent contrast-enhanced DECT (80-kVp and 150-kVp with a tin filter) in the portal venous phase for hepatic metastasis surveillance. Linearly blended images simulating 100-kVp images (100-kVp), standard 40-keV VMI images (40-keV VMI), and post-processed 40-keV VMI using a vendor-agnostic DLM (i.e., DLM 40-keV VMI) were reconstructed. Lesion conspicuity and diagnostic acceptability were assessed by three independent reviewers and compared using the Wilcoxon signed-rank test. The contrast-to-noise ratios (CNRs) were also measured placing ROIs in metastatic lesions and liver parenchyma. The detection performance of hepatic metastases was assessed by using a jackknife alternative free-response ROC method. The consensus by two independent radiologists was used as the reference standard. Results: DLM 40-keV VMI, compared to 40-keV VMI and 100-kVp, showed a higher lesion-to-liver CNR (8.25 ± 3.23 vs. 6.05 ± 2.38 vs. 5.99 ± 2.00), better lesion conspicuity (4.3 (4.0–4.7) vs. 3.7 (3.7–4.0) vs. 3.7 (3.3–4.0)), and better diagnostic acceptability (4.3 (4.0–4.3) vs. 3.0 (2.7–3.3) vs. 4.0 (4.0–4.3)) (p < 0.001 for all). For lesion detection (246 hepatic metastases in 68 patients), the figure of merit was significantly higher with DLM 40-keV VMI than with 40-keV VMI (0.852 vs. 0.822, p = 0.012), whereas no significant difference existed between DLM 40-keV VMI and 100-kVp (0.852 vs. 0.842, p = 0.31). Conclusions: DLM 40-keV VMI provided better image quality and comparable diagnostic performance for detecting hypoenhancing hepatic metastases compared to linearly blended images. Key Points: • DLM 40-keV VMI provides a superior image quality compared with 40-keV or 100-kVp for assessing hypoenhancing hepatic metastasis. • DLM 40-keV VMI has the highest CNR and lesion conspicuity score for hypoenhancing hepatic metastasis due to noise reduction and structural preservation. • DLM 40-keV VMI provides higher lesion detectability than standard 40-keV VMI (p = 0.012). [ABSTRACT FROM AUTHOR]

Objectives: To compare the image quality and diagnostic performance of 2D MRCP to those of breath-hold 3D MRCP using compressed sensing (CS-MRCP) and gradient and spin-echo (GRASE-MRCP) at 3T. Methods: From January to November 2018, patients who underwent pancreatobiliary MRI including 2D MRCP and two breath-hold 3D MRCP using CS and GRASE at 3T were included. Three radiologists independently evaluated image quality, motion artifact, and pancreatic cyst conspicuity. Diagnostic performance was assessed for bile duct anatomic variation, bile duct, and pancreatic diseases using a composite algorithm as reference standards. Pancreatic lesion detectability and conspicuity were evaluated using JAFROC and generalized estimating equation analysis. Results: One hundred patients (male = 50) were included. Bile duct anatomic variation, bile duct and pancreatic diseases were present in respectively 31, 15, and 79 patients. Breath-hold 3D MRCP provided better image quality than 2D MRCP (3.5 ± 0.6 in 2D MRCP; 4.0 ± 0.7 in GRASE-MRCP and 3.9 ± 0.8 in CS-MRCP, p < 0.001 for both). There was no difference in motion artifact between 2D and breath-hold 3D MRCP (p = 0.1). Breath-hold 3D CS-MRCP provided better pancreatic cyst conspicuity than 2D MRCP (2.7 [95% CI: 2.5–3.0] vs. 2.3 [95% CI: 2.1–2.5], p = 0.001). There were no significant differences between the diagnostic performance of the three sequences in the detection of bile duct anatomic variation or pancreatic lesions (p > 0.05). Conclusion: Breath-hold 3D MRCP with GRASE or CS can provide better image quality than 2D MRCP in a comparable scan time. Key Points: • Breath-hold 3D MRCP using compressed sensing (CS) or gradient and spin-echo (GRASE) provided a better image quality with less image blurring than 2D MRCP. • There were no significant differences between 2D MRCP and breath-hold 3D MRCP in either motion artifact or the number of non-diagnostic exams. • There were no significant differences between 2D MRCP and either type of breath-hold 3D MRCP in the diagnosis of bile duct anatomic variation or detection of pancreatic lesions. [ABSTRACT FROM AUTHOR]

Objectives: To investigate an additional value of [68Ga]Ga-DOTA-TOC PET/CT for characterizing suspected pancreatic neuroendocrine neoplasms (NENs) in a large study cohort. Methods: This retrospective study included 167 patients who underwent [68Ga]Ga-DOTA-TOC PET/CT for suspected pancreatic NENs detected by contrast-enhanced CT (n = 153) and/or MRI (n = 85). Two board-certified radiologists independently reviewed CT and/or MRI as well as [68Ga]Ga-DOTA-TOC PET/CT and scored the probability of NEN on a 5-point scale. Radiologists' diagnostic performances with and without [68Ga]Ga-DOTA-TOC PET/CT were compared using pathologic findings as the standard of reference. Results: All 167 patients were pathologically diagnosed with NENs (n = 131) or non-NENs (n = 36) by surgery (n = 93) or biopsy (n = 74). The non-NEN group included focal pancreatitis (n = 7), gastrointestinal stromal tumor (n = 6), serous cystadenoma (n = 5), metastatic renal cell carcinoma (n = 4), intrapancreatic accessory spleen (n = 4), ductal adenocarcinoma (n = 3), solid pseudopapillary neoplasm (n = 2), intraductal papillary mucinous carcinoma (n = 1), adenosquamous carcinoma (n = 1), schwannoma (n = 1), paraganglioma (n = 1), and solitary fibrous tumor (n = 1). Radiologists' diagnostic performance significantly improved after the addition of [68Ga]Ga-DOTA-TOC PET/CT (AUC of CT: 0.737 vs. 0.886 for reviewer 1 [p = 0.0004]; 0.709 vs. 0.859 for reviewer 2 [p = 0.0002], AUC of MRI: 0.748 vs. 0.872 for reviewer 1 [p = 0.023]; 0.670 vs. 0.854 for reviewer 2 [p = 0.001]). [68Ga]Ga-DOTA-TOC PET/CT significantly improved sensitivity (CT: 87.4% vs. 96.6% for reviewer 1 [p = 0.001]; 74.8% vs. 92.5% for reviewer 2 [p = 0.0001], MRI: 86.9% vs. 98.4% for reviewer 1 [p = 0.016]; 70.5% vs. 91.8% for reviewer 2 [p = 0.002]). Conclusions: [68Ga]Ga-DOTA-TOC PET/CT provided an additional value over conventional CT or MRI for the characterization of suspected pancreatic NENs. Key Points: • [68Ga]Ga-DOTA-TOC PET/CT could provide additional value over conventional CT and/or MRI for the exact characterization of suspected pancreatic NENs by increasing AUC values and sensitivity. • Diagnostic improvement was significant, especially in NENs showing an atypical enhancement pattern. • The inter-observer agreement was improved when [68Ga]Ga-DOTA-TOC PET/CT was added to CT and/or MRI. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether reduced field-of-view (rFOV) DWI sequences can improve image quality and diagnostic performance compared with conventional full FOV (fFOV) DWI in the prediction of complete response (CR) to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancers. Methods: Between September 2015 and December 2017, seventy-three patients with locally advanced rectal cancers (≥ T3 or lymph node positive) who underwent CRT and subsequent surgery were included in this retrospective study. All patients had tumor located no more than 10 cm from the anal verge, and underwent rectal MRI including fFOV b-1000 DWI and rFOV b-1000 DWI at 3 T before and after CRT. Image quality and diagnostic performance in predicting CR were compared between rFOV DWI and fFOV DWI sets by two reviewers. Results: Based on a 12-point scale, rFOV DWI provided better image quality scores than fFOV DWI (9.1 ± 1.7 vs. 8.4 ± 1.0, respectively, P < 0.001). Diagnostic accuracy (Az) in evaluating CR was better with the rFOV DWI set than with the fFOV DWI set for both reviewers: reviewer 1, 0.78 vs. 0.57 (P =.004); reviewer 2, 0.72 vs. 0.61 (P =.031). Conclusion: rFOV DWI of rectal cancer can provide better overall image quality, and its addition to conventional rectal MRI may provide better diagnostic accuracy than fFOV DWI in the evaluation of CR to neoadjuvant CRT in patients with locally advanced rectal cancer. [ABSTRACT FROM AUTHOR]

Objectives: To determine the prognostic value of CT-based splenic volume measurement in patients with compensated chronic liver disease (cCLD) from chronic hepatitis B (CHB). Methods: A total of 584 patients having multiphasic liver CT scans between January and December 2011 were retrospectively reviewed. Spleen volume was measured using a semi-automated three-dimensional volumetric software program. Electronic medical records and national registry data were reviewed to determine the diagnosis of hepatocellular carcinoma (HCC), hepatic decompensation, or death. The cumulative incidence (CI) of the development of decompensation, HCC occurrence, and overall survival (OS) were estimated by the Kaplan-Meier method. The Cox proportional hazard regression model was used to evaluate prognostic factors. The optimal cutoff spleen volume to predict each outcome was obtained using a minimal p value approach method. Results: After a median follow-up of 92 months, 114 patients developed HCC with a 7-year CI of 17.2%. A larger spleen volume was a significant predictor of HCC occurrence (HR = 2.13, p = 0.009). Decompensation occurred in 30 patients with a 7-year CI of 5.0%, and a larger spleen volume was also significantly associated with the development of decompensation (HR = 4.66, p = 0.005). Twenty-three patients died, and their estimated 7-year OS was 96.4%. A larger spleen volume also significantly affected OS (HR = 6.15, p = 0.007). The optimal cutoff spleen volume was set at 532 mL for HCC occurrence, 656.9 mL for the development of decompensation, and 741.1 mL for OS. Conclusions: A larger spleen volume was significantly associated with HCC occurrence, development of decompensation, and poor OS in patients with cCLD from CHB. Key Points: • Spleen volume could be easily acquired from routine multiphasic liver CT scan using a semi-automated 3D volumetric software program with excellent inter-observer agreement. • A larger spleen volume was significantly associated with a higher rate of hepatocellular carcinoma occurrence, the development of decompensation, and poor overall survival in patients with compensated chronic liver disease from chronic hepatitis B. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate diagnostic values of the liver imaging reporting and data system (LI-RADS) M (LR-M) category based on novel explicit criteria that accept both targetoid and nontargetoid LR-M features and the suggested reporting algorithm of LI-RADS v2018 to assess primary liver cancers (PLCs) on gadoxetic acid-enhanced MRI (Gd-EOB-MRI). Methods: This retrospective study included 165 patients at high risk for hepatocellular carcinoma (HCC) with pathologically confirmed PLCs (HCC, n = 113; intrahepatic cholangiocarcinoma [iCCA], n = 23; and combined hepatocellular cholangiocarcinoma [cHCC-CCA], n = 29). Two radiologists independently analyzed Gd-EOB-MRI features and determined LI-RADS category for each tumor and categorized the likely etiology either as HCC or non-HCC malignancy if LR-M was assigned. Diagnostic performances for HCC or those for malignancy were compared according to imaging criteria. Results: LR-M was assigned in 95.7%/91.3% of iCCAs; 55.2%/58.6% of cHCC-CCAs; and 21.2%/17.7% of HCCs in reviewers 1/2. Combination of LR-5 plus LR-M resulted in sensitivity of 95.2%/97.6% to diagnose PLCs as malignant, which were significantly higher than that of LR-5 plus "LR-M with ≥ 1 targetoid appearances" (84.8%/91.5%, Ps < 0.01). In comparison to LR-5, LR-5 plus "LR-M of HCC as likely etiology" resulted in significant increase in sensitivity (73.5%/79.6% versus 87.6%/92.9%, Ps < 0.001) but significant decrease in specificity (76.9%/75.0% versus 57.7%/50.0%, P = 0.002 and < 0.001) in the diagnosis of HCC. Conclusion: The LR-M criteria v2018 are useful to differentiate non-HCC malignancies from HCCs and to accurately diagnose PLCs as a malignancy. Reporting the likely etiology in LR-M may facilitate a more sensitive detection of HCC, but along with a considerable decrease in specificity. [ABSTRACT FROM AUTHOR]

Ultrasonography (US) has been considered image of choice for gallbladder (GB) polyp, however, it had limitations in differentiating between nonneoplastic polyps and neoplastic polyps. We developed and investigated the usefulness of a deep learning-based decision support system (DL-DSS) for the differential diagnosis of GB polyps on US. We retrospectively collected 535 patients, and they were divided into the development dataset (n = 437) and test dataset (n = 98). The binary classification convolutional neural network model was developed by transfer learning. Using the test dataset, three radiologists with different experience levels retrospectively graded the possibility of a neoplastic polyp using a 5-point confidence scale. The reviewers were requested to re-evaluate their grades using the DL-DSS assistant. The areas under the curve (AUCs) of three reviewers were 0.94, 0.78, and 0.87. The DL-DSS alone showed an AUC of 0.92. With the DL-DSS assistant, the AUCs of the reviewer's improved to 0.95, 0.91, and 0.91. Also, the specificity of the reviewers was improved (65.1–85.7 to 71.4–93.7). The intraclass correlation coefficient (ICC) improved from 0.87 to 0.93. In conclusion, DL-DSS could be used as an assistant tool to decrease the gap between reviewers and to reduce the false positive rate. [ABSTRACT FROM AUTHOR]

Objective: To investigate the presence of gender disparity in academic involvement during radiology residency and to identify and characterize any gender differences in perceived barriers for conducting research. Methods: An international call for participation in an online survey was promoted via social media and through multiple international and national radiological societies. A 35-question survey invited radiology trainees worldwide to answer questions regarding exposure and barriers to academic radiology during their training. Gender differences in response proportions were analyzed using either Fisher's exact or chi-squared tests. Results: Eight hundred fifty-eight participants (438 men, 420 women) from Europe (432), Asia (241), North and South America (144), Africa (37), and Oceania (4) completed the survey. Fewer women radiology residents were involved in research during residency (44.3%, 186/420 vs 59.4%, 260/438; p ≤ 0.0001) and had fewer published original articles (27.9%, 117/420 vs. 40.2%, 176/438; p = 0.001). Women were more likely to declare gender as a barrier to research (24.3%, 102/420 vs. 6.8%, 30/438; p < 0.0001) and lacked mentorship/support from faculty (65%, 273/420 vs. 55.7%, 244/438; p = 0.0055). Men were more likely to declare a lack of time (60.3%, 264/438 vs. 50.7%, 213/420; p = 0.0049) and lack of personal interest (21%, 92/438 vs. 13.6%, 57/420, p = 0.0041) in conducting research. Conclusion: Fewer women were involved in academic activities during radiology residency, resulting in fewer original published studies compared to their men counterparts. This is indicative of an inherent gender imbalance. Lack of mentorship reported by women radiologists was a main barrier to research. [ABSTRACT FROM AUTHOR]

Meteotsunamis originating from atmospheric pressure disturbances have frequently occurred in oceans worldwide and their destructive long waves have recently threatened local coastal communities. In particular, meteotsunamis occurring in the Yellow Sea caused unexpected casualties and property damage to local communities on the western coast of the Korean Peninsula in 2007 and 2008. These events attracted the attention of many engineers and scientists because abrupt extreme waves have struck several coasts and ports even under fine weather conditions. Furthermore, the Yellow Sea has the highest tide and most powerful tidal currents in the world, and consequently, meteotsunami events there could be more destructive and harmful to local coastal communities when such events occur during high tide or a critical phase with strong tidal currents. In this study, numerical experiments were conducted to identify the qualitative effect of the interaction between a meteotsunami and the tide on the generation and amplification mechanisms of meteotsunamis occurring in the Yellow Sea. In general, small-scale meteotsunamis, such as those that occur in the Yellow Sea, should be analyzed using a high-resolution modeling system because water motions can be affected by local terrain. To achieve this objective, high-resolution atmospheric modeling was conducted to reproduce the atmospheric pressure disturbances observed in the Yellow Sea; then, the generation and propagation of the meteotsunami over real topographies was simulated using a phase-resolving wave model. Both an atmospheric model (Weather Research and Forecasting Model (WRF)) and a shallow water equation model (COrnell Multigrid COupled Tsunami Model (COMCOT)) were employed to simulate the generation and transformation of the meteotsunami. [ABSTRACT FROM AUTHOR]

Objective: To investigate the presence of gender disparity in academic involvement during radiology residency and to identify and characterize any gender differences in perceived barriers for conducting research. Methods: An international call for participation in an online survey was promoted via social media and through multiple international and national radiological societies. A 35-question survey invited radiology trainees worldwide to answer questions regarding exposure and barriers to academic radiology during their training. Gender differences in response proportions were analyzed using either Fisher's exact or chi-squared tests. Results: Eight hundred fifty-eight participants (438 men, 420 women) from Europe (432), Asia (241), North and South America (144), Africa (37), and Oceania (4) completed the survey. Fewer women radiology residents were involved in research during residency (44.3%, 186/420 vs 59.4%, 260/438; p ≤ 0.0001) and had fewer published original articles (27.9%, 117/420 vs. 40.2%, 176/438; p = 0.001). Women were more likely to declare gender as a barrier to research (24.3%, 102/420 vs. 6.8%, 30/438; p < 0.0001) and lacked mentorship/support from faculty (65%, 273/420 vs. 55.7%, 244/438; p = 0.0055). Men were more likely to declare a lack of time (60.3%, 264/438 vs. 50.7%, 213/420; p = 0.0049) and lack of personal interest (21%, 92/438 vs. 13.6%, 57/420, p = 0.0041) in conducting research. Conclusion: Fewer women were involved in academic activities during radiology residency, resulting in fewer original published studies compared to their men counterparts. This is indicative of an inherent gender imbalance. Lack of mentorship reported by women radiologists was a main barrier to research. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether mass stiffness measured by shear-wave elastography (SWE) can predict the histological upgrade of ductal carcinoma in situ (DCIS) confirmed through ultrasound (US)-guided core needle biopsy (CNB).Methods: The institutional review board approved this study and informed consent was waived. A database search revealed 120 biopsy-confirmed DCIS in patients who underwent B-mode US and SWE prior to surgery. Clinicopathologic results, B-mode findings, size on US, and mean and maximum elasticity values on SWE were recorded. Associations between upgrade to invasive cancer and B-mode US findings, SWE information, and clinical variables were assessed using univariate, multivariate logistic regression, and multiple linear regression analysis.Results: The overall upgrade rate was 41.7 % (50/120). Mean stiffness value (P = .014) and mass size (P = .001) were significantly correlated with histological upgrade. The optimal cut-off value of mean stiffness value, yielding the maximal sum of sensitivity and specificity, was 70.7 kPa showing sensitivity of 72 % and specificity of 65.7 % for detecting invasiveness. Qualitative elasticity colour scores were significantly correlated with the histological upgrade, mammographic density, and B-mode category (P < .04).Conclusion: Mean stiffness values evaluated through SWE can be utilized as a preoperative predictor of histological upgrade to invasive cancer in DCIS confirmed at US-guided needle biopsy.Key Points: • Higher stiffness values were noted in invasive cancer than DCIS. • Qualitative SWE colour scores significantly correlated with the histological upgrade. • Qualitative SWE colour scores had excellent interobserver agreement. [ABSTRACT FROM AUTHOR]

Purpose: To assess the measurement variability of subsolid nodules (SSNs) in follow-up situations and to compare the degree of variability between measurement metrics. Methods: Two same-day repeat-CT scans of 69 patients (24 men and 45 women) with 69 SSNs were randomly assigned as initial or follow-up scans and were read by the same (situation 1) or different readers (situation 2). SSN size and solid portion size were measured in both situations. Measurement variability was calculated and coefficients of variation were used for comparisons. Results: Measurement variability for the longest and average diameter of SSNs was ±1.3 mm (±13.0%) and ±1.3 mm (±14.4%) in situation 1, and ±2.2 mm (±21.0%) and ±2.1 mm (±21.3%) in situation 2, respectively. For solid portion, measurement variability on lung and mediastinal windows was ±1.2 mm (±27.1%) and ±0.8 mm (±24.0%) in situation 1, and ±3.7 mm (±61.0%) and ±1.5 mm (±47.3%) in situation 2, respectively. There were no significant differences in the degree of variability between the longest and average diameters and between the lung and mediastinal window settings (p>0.05). However, measurement variability significantly increased when the follow-up and initial CT readers were different (p<0.001). Conclusions: A cutoff of ±2.2 mm can be reliably used to determine true nodule growth on follow-up CT. Solid portion measurements were not reliable in evaluating SSNs’ change when readers of initial and follow-up CT were different. [ABSTRACT FROM AUTHOR]

Objectives: To retrospectively investigate the added value of quantitative 3D shape analysis in differentiating encapsulated from invasive thymomas. Materials and Methods: From February 2002 to October 2013, 53 patients (25 men and 28 women; mean age, 53.94 ± 13.13 years) with 53 pathologically-confirmed thymomas underwent preoperative chest CT scans (slice thicknesses ≤ 2.5 mm). Twenty-three tumors were encapsulated thymomas and 30 were invasive thymomas. Their clinical and CT characteristics were evaluated. In addition, each thymoma was manually-segmented from surrounding structures, and their 3D shape features were assessed using an in-house developed software program. To evaluate the added value of 3D shape features in differentiating encapsulated from invasive thymomas, logistic regression analysis and receiver-operating characteristics curve (ROC) analysis were performed. Results: Significant differences were observed between encapsulated and invasive thymomas, in terms of cystic changes (p=0.004), sphericity (p=0.016), and discrete compactness (p=0.001). Subsequent binary logistic regression analysis revealed that absence of cystic change (adjusted odds ratio (OR) = 6.636; p=0.015) and higher discrete compactness (OR = 77.775; p=0.012) were significant differentiators of encapsulated from invasive thymomas. ROC analyses revealed that the addition of 3D shape analysis to clinical and CT features (AUC, 0.955; 95% CI, 0.935–0.975) provided significantly higher performance in differentiating encapsulated from invasive thymomas than clinical and CT features (AUC, 0.666; 95% CI, 0.626–0.707) (p<0.001). Conclusion: Addition of 3D shape analysis, particularly discrete compactness, can improve differentiation of encapsulated thymomas from invasive thymomas. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the effect of clopidogrel vs. aspirin monotherapy on vascular function and hemostatic measurement. Background: Monotherapy with P2Y12 receptor inhibitor vs. aspirin can be a useful alterative to optimize clinical efficacy and safety in high-risk patients with coronary artery disease (CAD). Methods: We performed a randomized, open-label, two-period crossover study in stented patients receiving at least 6-month of dual antiplatelet therapy (DAPT). Thirty CAD patients with moderate-to-high ischemic risk were randomly assigned to receive either 75 mg of clopidogrel or 100 mg of aspirin daily for 4 weeks, and were crossed over to the other strategy for 4 weeks. Vascular function was evaluated with reactive hyperemia-peripheral arterial tonometry (RH-PAT) and brachial-ankle pulse wave velocity (baPWV). Hemostatic profiles were measured with VerifyNow and thromboelastography (TEG). The primary endpoint was the reactive hyperemia index (RHI) during clopidogrel or aspirin monotherapy. Results: Clopidogrel vs. aspirin monotherapy was associated with better endothelial function (RHI: 2.11 ± 0.77% vs. 1.87 ± 0.72%, p = 0.045), lower platelet reactivity (130 ± 64 vs. 214 ± 50 P2Y12 reaction unit [PRU], p < 0.001) and prolonged reaction time (TEG R: 5.5 ± 1.2 vs. 5.1 ± 1.1 min, p = 0.037). In multivariate analysis, normal endothelial function (RHI ≥ 2.1) was significantly associated with clot kinetics (TEG angle ≤ 68 degree) and 'PRU ≤ 132'. 'PRU ≤ 132' was achieved in 46.2% vs. 3.8% during clopidogrel administration vs. aspirin monotherapy (odds ratio 21.4, 95% confidence interval 2.7 to 170.1, p < 0.001). Conclusions: In CAD patients, clopidogrel vs. aspirin monotherapy was associated with better endothelial function, greater platelet inhibition and lower coagulation activity, suggesting pleiotropic effects of clopidogrel on endothelial function and hemostatic profiles. [ABSTRACT FROM AUTHOR]