Introduction and evaluation of size-specific DLP for radiation dose estimation in CT examinations.

The increased utilization of computed tomography (CT) has raised concerns about patient radiation exposure. Effective dose (ED), which requires precise estimation, is crucial for assessing and managing these risks. Traditional ED estimation methods, which are based on the dose-length product (DLP), often lack accuracy due to variations in patient size and anatomy. This study aims to evaluate the efficacy of size-specific DLP (SS-DLP), a novel metric that combines the size-specific dose estimate (SSDE) with scan length, to provide a more accurate estimation of radiation exposure from CT examinations.　Focusing on adult chest-abdomen-pelvis (CAP) scans, we calculated SSDE and SS-DLP and utilized two simulation tools, Radimetrics and WAZA-ARI, for a detailed analysis. Our findings indicate that SS-DLP is highly correlated with EDs from Monte Carlo simulations, suggesting its reliability. Additionally, SS-DLP showed a moderate reduction in errors based on patient sex and body mass index compared to traditional DLP-based methods. Thus, SS-DLP offers a more accurate and personalized radiation exposure estimate, potentially enhancing patient safety.

Role of radiologists in the diagnosis and management of adrenal disorders.

This study aimed to focus on the role of radiologists in the diagnosis and management of adrenal lesions, particularly primary aldosteronism (PA) and secondary hypertension. As hypertension affects more than one-third of the population in Japan, identifying secondary causes such as PA and adrenal lesions is crucial. Establishing a radiological differential diagnosis of adrenal lesions using advanced imaging techniques, such as computed tomography and magnetic resonance imaging, is crucial. Knowledge of the imaging findings of various benign and malignant adrenal lesions, such as adrenocortical adenomas, cortisol-producing lesions, pheochromocytomas, adrenocortical carcinoma, malignant lymphoma, and metastatic tumors, is necessary. Adrenal venous sampling (AVS) plays a crucial role in accurately localizing aldosterone hypersecretion in PA, especially when imaging fails to provide a clear diagnosis. This paper details the technical aspects of AVS, emphasizing catheterization techniques, anatomical considerations, and the importance of preprocedural imaging for successful sampling. Furthermore, we explore segmental adrenal venous sampling (SAVS), a more refined technique that samples specific adrenal tributary veins, offering enhanced diagnostic accuracy, particularly for microadenomas or challenging cases that may be missed with conventional AVS. The methodology for performing SAVS, along with the interpretation criteria for successful sampling and lateralization, is also outlined. Furthermore, radiologists have initiated treatments for unilateral PA, such as radiofrequency ablation, and play an integral role in the management of adrenal lesions. Collaborative approaches across clinical departments are required to enhance patient management in medical care involving the adrenal gland.

Post-TACE FDG Accumulation in HCC Surrounding the Liver Parenchyma: Distinguishing Between Inflammatory Pseudotumors and HCC.

ABSTRACT: An 80-year-old patient with hepatocellular carcinoma (HCC) underwent an 18 F-FDG PET/CT scan owing to suspected lumbar metastasis identified via a CT scan performed during transarterial chemoembolization (TACE) 2 weeks earlier. The PET scan revealed segmental high uptake in the HCC and surrounding liver parenchyma, where lipiodol deposited during TACE had mostly washed out. The segmental uptake was attributed to TACE-induced inflammatory changes in the liver parenchyma around the HCC, confirmed by reduced uptake in a follow-up 18 F-FDG PET/CT scan 4 months later. This highlights the need to differentiate between inflammation and viable HCC in post-TACE 18 F-FDG PET/CT evaluations.

Cost-effectiveness analysis of segmental adrenal venous sampling with radiofrequency ablation for primary aldosteronism in Japan.

PURPOSE: The purpose of this study was to evaluate the cost-effectiveness of comprehensive treatment strategy, including segmental adrenal venous sampling (sAVS) and radiofrequency ablation (RFA), versus medication-only strategy for primary aldosteronism. MATERIALS AND METHODS: A Markov decision model was developed to compare the cost-effectiveness of a comprehensive treatment strategy and a medication-only strategy for 50-year-old men and women with stage I-III hypertension. The comprehensive treatment strategy included aldosterone/renin ratio measurement, two loading tests, computed tomography, sAVS, drugs, surgery, and RFA. We built a model with a yearly cycle over 32- and 38-year time horizons for men and women, respectively, and four health states: hypertension, heart failure, stroke, and death. The incremental cost-effectiveness ratio (ICER), expressed as Japanese yen per quality-adjusted life-years (QALYs), was estimated, and strategy preference was determined on the basis of 5 million Japanese yen per QALY societal willingness-to-pay threshold. RESULTS: The ICERs of the comprehensive treatment strategy over the medication-only strategy were 201,482 and 3,399 JPY per QALY for men and women, respectively. The resultant ICER was less than the 5 million JPY societal willingness-to-pay threshold. Deterministic sensitivity analysis and probabilistic sensitivity analysis revealed that the results varied with the input values, but the comprehensive strategy was likely to be more cost-effective than the medication-only strategy. CONCLUSION: This cost-effectiveness study revealed that a comprehensive treatment strategy including sAVS and RFA was favorable compared with the medication-only strategy for managing stage I-III hypertension in 50-year-old men and women, with acceptable willingness-to-pay thresholds. This cost-effectiveness study revealed that a comprehensive treatment strategy for primary aldosteronism that included segmental adrenal sampling and radiofrequency ablation was favorable compared with the medication-only strategy for managing stage I-III hypertension in 50-year-old men and women, with acceptable willingness-to-pay thresholds.

Verification of the effect of data-driven brain motion correction on PET imaging.

INTRODUCTION: Brain positron emission tomography/computed tomography (PET/CT) scans are useful for identifying the cause of dementia by evaluating glucose metabolism in the brain with F-18-fluorodeoxyglucose or Aß deposition with F-18-florbetaben. However, since imaging time ranges from 10 to 30 minutes, movements during the examination might result in image artifacts, which interfere with diagnosis. To solve this problem, data-driven brain motion correction (DDBMC) techniques are capable of performing motion corrected reconstruction using highly accurate motion estimates with high temporal resolution. In this study, we investigated the effectiveness of DDBMC techniques on PET/CT images using a Hoffman phantom, involving continuous rotational and tilting motion, each expanded up to approximately 20 degrees. MATERIALS AND METHODS: Listmode imaging was performed using a Hoffman phantom that reproduced rotational and tilting motions of the head. Brain motion correction processing was performed on the obtained data. Reconstructed images with and without brain motion correction processing were compared. Visual evaluations by a nuclear medicine specialist and quantitative parameters of images with correction and reference still images were compared. RESULTS: Normalized Mean Squared Error (NMSE) results demonstrated the effectiveness of DDBMC in compensating for rotational and tilting motions during PET imaging. In Cases 1 and 2 involving rotational motion, NMSE decreased from 0.15-0.2 to approximately 0.01 with DDBMC, indicating a substantial reduction in differences from the reference image across various brain regions. In the Structural Similarity Index (SSIM), DDBMC improved it to above 0.96 Contrast assessment revealed notable improvements with DDBMC. In continuous rotational motion, % contrast increased from 42.4% to 73.5%, In tilting motion, % contrast increased from 52.3% to 64.5%, eliminating significant differences from the static reference image. These findings underscore the efficacy of DDBMC in enhancing image contrast and minimizing motion induced variations across different motion scenarios. CONCLUSIONS: DDBMC processing can effectively compensate for continuous rotational and tilting motion of the head during PET, with motion angles of approximately 20 degrees. However, a significant limitation of this study is the exclusive validation of the proposed method using a Hoffman phantom; its applicability to the human brain has not been investigated. Further research involving human subjects is necessary to assess the generalizability and reliability of the presented motion correction technique in real clinical scenarios.

Prophylactic splenic artery embolization using n-butyl-2-cyanoacrylate and coils prior to endoscopic necrosectomy in a patient with necrotizing pancreatitis: A case report.

We present a case of prophylactic endovascular embolization in a 51-year-old man with necrotizing pancreatitis (NP) before undergoing endoscopic necrosectomy (EN). Contrast-enhanced CT imaging revealed the presence of a walled-off necrosis (WON) surrounding the pancreas, with the splenic artery coursing through the cavity. The splenic artery was embolized using n-butyl-2-cyanoacrylate (NBCA) and coils to mitigate the risk of massive bleeding in EN. A newly developed polytetrafluoroethylene (PTFE)-coated microcatheter was used to inject NBCA, enabling embolization of a long segment of the splenic artery without adhering to the vessel wall. Coils were placed distal and proximal to the embolized segment to optimize control. Over 5 sessions of EN, no massive bleeding was encountered. This report demonstrates the benefits of utilizing PTFE-coated microcatheters for enhanced safety and maneuverability during embolization with NBCA. Furthermore, it highlights the importance of prophylactic embolization during EN for managing NP.

Predicting EGFR Status After Radical Nephrectomy or Partial Nephrectomy for Renal Cell Carcinoma on CT Using a Self-attention-based Model: Variable Vision Transformer (vViT).

OBJECTIVE: To assess the effectiveness of the vViT model for predicting postoperative renal function decline by leveraging clinical data, medical images, and image-derived features; and to identify the most dominant factor influencing this prediction. MATERIALS AND METHODS: We developed two models, eGFR10 and eGFR20, to identify patients with a postoperative reduction in eGFR of more than 10 and more than 20, respectively, among renal cell carcinoma patients. The eGFR10 model was trained on 75 patients and tested on 27, while the eGFR20 model was trained on 77 patients and tested on 24. The vViT model inputs included class token, patient characteristics (age, sex, BMI), comorbidities (peripheral vascular disease, diabetes, liver disease), habits (smoking, alcohol), surgical details (ischemia time, blood loss, type and procedure of surgery, approach, operative time), radiomics, and tumor and kidney imaging. We used permutation feature importance to evaluate each sector's contribution. The performance of vViT was compared with CNN models, including VGG16, ResNet50, and DenseNet121, using McNemar and DeLong tests. RESULTS: The eGFR10 model achieved an accuracy of 0.741 and an AUC-ROC of 0.692, while the eGFR20 model attained an accuracy of 0.792 and an AUC-ROC of 0.812. The surgical and radiomics sectors were the most influential in both models. The vViT had higher accuracy and AUC-ROC than VGG16 and ResNet50, and higher AUC-ROC than DenseNet121 (p < 0.05). Specifically, the vViT did not have a statistically different AUC-ROC compared to VGG16 (p = 1.0) and ResNet50 (p = 0.7) but had a statistically different AUC-ROC compared to DenseNet121 (p = 0.87) for the eGFR10 model. For the eGFR20 model, the vViT did not have a statistically different AUC-ROC compared to VGG16 (p = 0.72), ResNet50 (p = 0.88), and DenseNet121 (p = 0.64). CONCLUSION: The vViT model, a transformer-based approach for multimodal data, shows promise for preoperative CT-based prediction of eGFR status in patients with renal cell carcinoma.

Predicting isocitrate dehydrogenase status among adult patients with diffuse glioma using patient characteristics, radiomic features, and magnetic resonance imaging: Multi-modal analysis by variable vision transformer.

OBJECTIVES: To evaluate the performance of the multimodal model, termed variable Vision Transformer (vViT), in the task of predicting isocitrate dehydrogenase (IDH) status among adult patients with diffuse glioma. MATERIALS AND METHODS: vViT was designed to predict IDH status using patient characteristics (sex and age), radiomic features, and contrast-enhanced T1-weighted images (CE-T1WI). Radiomic features were extracted from each enhancing tumor (ET), necrotic tumor core (NCR), and peritumoral edematous/infiltrated tissue (ED). CE-T1WI were split into four images and input to vViT. In the training, internal test, and external test, 271 patients with 1070 images (535 IDH wildtype, 535 IDH mutant), 35 patients with 194 images (97 IDH wildtype, 97 IDH mutant), and 291 patients with 872 images (436 IDH wildtype, 436 IDH mutant) were analyzed, respectively. Metrics including accuracy and AUC-ROC were calculated for the internal and external test datasets. Permutation importance analysis combined with the Mann-Whitney U test was performed to compare inputs. RESULTS: For the internal test dataset, vViT correctly predicted IDH status for all patients. For the external test dataset, an accuracy of 0.935 (95% confidence interval; 0.913-0.945) and AUC-ROC of 0.887 (0.798-0.956) were obtained. For both internal and external test datasets, CE-T1WI ET radiomic features and patient characteristics had higher importance than other inputs (p < 0.05). CONCLUSIONS: The vViT has the potential to be a competent model in predicting IDH status among adult patients with diffuse glioma. Our results indicate that age, sex, and CE-T1WI ET radiomic features have key information in estimating IDH status.

Screening Cutoff Values for the Detection of Aldosterone-Producing Adenoma by LC-MS/MS and a Novel Noncompetitive CLEIA.

Context: Detecting patients with surgically curable aldosterone-producing adenoma (APA) among hypertensive individuals is clinically pivotal. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the ideal method of measuring plasma aldosterone concentration (PAC) because of the inaccuracy of conventional chemiluminescent enzyme immunoassay (CLEIA). However, LC-MS/MS is expensive and requires expertise. We have developed a novel noncompetitive CLEIA (NC-CLEIA) for measuring PAC in 30 minutes. Objective: This work aimed to validate NC-CLEIA PAC measurements by comparing them with LC-MS/MS measurements and determining screening cutoffs for both measurements detecting APA. Methods: We retrospectively measured PAC using LC-MS/MS and NC-CLEIA in 133 patients with APA, 100 with bilateral hyperaldosteronism, and 111 with essential hypertension to explore the accuracy of NC-CLEIA PAC measurements by comparing with LC-MS/MS measurements and determined the cutoffs for detecting APA. Results: Passing-Bablok analysis revealed that the values by NC-CLEIA (the regression slope, intercept, and correlation coefficient were 0.962, -0.043, and 0.994, respectively) were significantly correlated and equivalent to those by LC-MS/MS. Bland-Altman plot analysis of NC-CLEIA and LC-MS/MS also demonstrated smaller systemic errors (a bias of -0.348 ng/dL with limits of agreement of -4.390 and 3.694 within a 95% CI) in NC-CLEIA than LC-MS/MS. The receiver operating characteristic analysis demonstrated that cutoff values for aldosterone/renin activity ratio obtained by LC-MS/MS and NC-CLEIA were 31.2 and 31.5 (ng/dL per ng/mL/hour), with a sensitivity of 91.0% and 90.2% and specificity of 75.4% and 76.8%, respectively, to differentiate APA from non-APA. Conclusion: This newly developed NC-CLEIA for measuring PAC could serve as a clinically reliable alternative to LC-MS/MS.

Novel method for classification of prion diseases by detecting PrPres signal patterns from formalin-fixed paraffin-embedded samples.

Prion disease is an infectious and fatal neurodegenerative disease. Western blotting (WB)-based identification of proteinase K (PK)-resistant prion protein (PrPres) is considered a definitive diagnosis of prion diseases. In this study, we aimed to detect PrPres using formalin-fixed paraffin-embedded (FFPE) specimens from cases of sporadic Creutzfeldt-Jakob disease (sCJD), Gerstmann-Sträussler-Scheinker disease (GSS), glycosylphosphatidylinositol-anchorless prion disease (GPIALP), and V180I CJD. FFPE samples were prepared after formic acid treatment to inactivate infectivity. After deparaffinization, PK digestion was performed, and the protein was extracted. In sCJD, a pronounced PrPres signal was observed, with antibodies specific for type 1 and type 2 PrPres exhibited a strong or weak signals depending on the case. Histological examination of serial sections revealed that the histological changes were compatible with the biochemical characteristics. In GSS and GPIALP, prion protein core-specific antibodies presented as PrPres bands at 8-9 kDa and smear bands, respectively. However, an antibody specific for the C-terminus presented as smears in GSS, with no PrPres detected in GPIALP. It was difficult to detect PrPres in V180I CJD. Collectively, our findings demonstrate the possibility of detecting PrPres in FFPE and classifying the prion disease types. This approach facilitates histopathological and biochemical evaluation in the same sample and is safe owing to the inactivation of infectivity. Therefore, it may be valuable for the diagnosis and research of prion diseases.

Two-session embolization of portosystemic shunt presenting with hepatic encephalopathy via transvenous and trans-paraumbilical approaches: A case report.

We describe the endovascular embolization of a 65-year-old man with chronic hepatic encephalopathy. A contrast-enhanced computed tomography demonstrated a splenorenal shunt and a recanalized paraumbilical vein as a continuous portal shunt connecting the left branch of the portal vein and the right common femoral vein. A 2-session embolization was performed for the splenorenal shunt. First, the transvenous approach was used for coil embolization of the splenorenal shunt. It was difficult to advance the catheter system to the embolization site, and it was unstable during coil placement. Second, the paraumbilical venous approach was used to place additional coils. The catheter system had good maneuverability and easily reached the embolization site. Additionally, the stable system allowed for densely packed additional coil implantations. This report demonstrated the paraumbilical venous approach's effectiveness in catheter maneuverability and system stability during coil embolization.

Impact of Work Environment on Job Satisfaction among Interventional Radiologists in Japan: A Cross-sectional Study.

Purpose: This study aims to measure job satisfaction among interventional radiology physicians in Japan and analyze the factors affecting job satisfaction. Material and Methods: A web-based survey was conducted among the members of the Japanese Society of Interventional Radiology between October and December 2021. Participants were questioned regarding their job satisfaction, workplace, work status, and demographic information. Principal component analysis was applied to 15 reasons related to job satisfaction, and the factors affecting job satisfaction were analyzed. Results: Valid responses were obtained from 901 (31.9%) of the 2,824 interventional radiology physicians invited to participate. Job satisfaction was reported as "very satisfied" in 79 (8.8%), "moderately satisfied" in 426 (47.3%), "neither satisfied nor dissatisfied" in 230 (25.5%), "moderately dissatisfied" in 133 (14.8%), and "very dissatisfied" in 33 (3.7%) respondents. Thus, there were 505 (56.0%) satisfied physicians. Three principal components were extracted from the reasons for job satisfaction. Job satisfaction tended to be higher among those who reported performing a higher number of interventional radiology procedures and was positively associated with a higher rate of work time dedicated to interventional radiology and the first principal component (the environment of clinical practice, research, and interventional radiology education). The third principal component (salary and work environment) and the absence of an "IkuBoss" [a boss who takes initiative in creating a work environment supportive of the work-life balance of colleagues] were associated with lower job satisfaction. Conclusions: More than half the participants reported high job satisfaction. Job satisfaction of interventional radiology physicians in Japan was positively associated with a favorable clinical, research, and educational environment and negatively associated with the absence of an "IkuBoss," noninterventional radiology work, overtime work, and salary.

Identifying key factors for predicting O6-Methylguanine-DNA methyltransferase status in adult patients with diffuse glioma: a multimodal analysis of demographics, radiomics, and MRI by variable Vision Transformer.

PURPOSE: This study aimed to perform multimodal analysis by vision transformer (vViT) in predicting O6-methylguanine-DNA methyl transferase (MGMT) promoter status among adult patients with diffuse glioma using demographics (sex and age), radiomic features, and MRI. METHODS: The training and test datasets contained 122 patients with 1,570 images and 30 patients with 484 images, respectively. The radiomic features were extracted from enhancing tumors (ET), necrotic tumor cores (NCR), and the peritumoral edematous/infiltrated tissues (ED) using contrast-enhanced T1-weighted images (CE-T1WI) and T2-weighted images (T2WI). The vViT had 9 sectors; 1 demographic sector, 6 radiomic sectors (CE-T1WI ET, CE-T1WI NCR, CE-T1WI ED, T2WI ET, T2WI NCR, and T2WI ED), 2 image sectors (CE-T1WI, and T2WI). Accuracy and area under the curve of receiver-operating characteristics (AUC-ROC) were calculated for the test dataset. The performance of vViT was compared with AlexNet, GoogleNet, VGG16, and ResNet by McNemar and Delong test. Permutation importance (PI) analysis with the Mann-Whitney U test was performed. RESULTS: The accuracy was 0.833 (95% confidence interval [95%CI]: 0.714-0.877) and the area under the curve of receiver-operating characteristics was 0.840 (0.650-0.995) in the patient-based analysis. The vViT had higher accuracy than VGG16 and ResNet, and had higher AUC-ROC than GoogleNet (p<0.05). The ED radiomic features extracted from the T2-weighted image demonstrated the highest importance (PI=0.239, 95%CI: 0.237-0.240) among all other sectors (p<0.0001). CONCLUSION: The vViT is a competent deep learning model in predicting MGMT status. The ED radiomic features of the T2-weighted image demonstrated the most dominant contribution.

Investigating the cut-off values of captopril challenge test for primary aldosteronism using the novel chemiluminescent enzyme immunoassay method: a retrospective cohort study.

The measurement evolution enabled more accurate evaluation of aldosterone production in hypertensive patients. However, the cut-off values for novel assays have been not sufficiently validated. The present study was undertaken to validate the novel chemiluminescent enzyme immunoassay for aldosterone in conjunction with other methods. Moreover, we also aimed to establish a new cut-off value for primary aldosteronism in the captopril challenge test using the novel assay. First, we collected 390 plasma samples, in which aldosterone levels measured using liquid chromatography-mass spectrometry ranged between 0.18 and 1346 ng/dL. The novel chemiluminescent enzyme immunoassay showed identical correlation of plasma aldosterone with liquid chromatography-mass spectrometry, in contrast to conventional radioimmunoassay. Further, we enrolled 299 and 39 patients with primary aldosteronism and essential hypertension, respectively. Plasma aldosterone concentrations measured using the novel assay were lower than those measured by radioimmunoassay, which resulted in decreased aldosterone-to-renin ratios. Subsequently, positive results of the captopril challenge test based on radioimmunoassay turned into "negative" based on the novel assay in 45% patients with primary aldosteronism, using the conventional cut-off value (aldosterone-to-renin activity ratio > 20 ng/dL per ng/mL/h). Receiver operating characteristic curve analysis demonstrated that aldosterone-to-renin activity ratios > 8.2 ng/dL per ng/mL/h in the novel assay was compatible with the conventional diagnosis (sensitivity, 0.874; specificity, 0.980). Our study indicates the great measurement accuracy of the novel chemiluminescent enzyme immunoassay for aldosterone, and the importance of measurement-adjusted cut-offs in the diagnosis of primary aldosteronism.

Performance evaluation of ChatGPT, GPT-4, and Bard on the official board examination of the Japan Radiology Society.

PURPOSE: Herein, we assessed the accuracy of large language models (LLMs) in generating responses to questions in clinical radiology practice. We compared the performance of ChatGPT, GPT-4, and Google Bard using questions from the Japan Radiology Board Examination (JRBE). MATERIALS AND METHODS: In total, 103 questions from the JRBE 2022 were used with permission from the Japan Radiological Society. These questions were categorized by pattern, required level of thinking, and topic. McNemar's test was used to compare the proportion of correct responses between the LLMs. Fisher's exact test was used to assess the performance of GPT-4 for each topic category. RESULTS: ChatGPT, GPT-4, and Google Bard correctly answered 40.8% (42 of 103), 65.0% (67 of 103), and 38.8% (40 of 103) of the questions, respectively. GPT-4 significantly outperformed ChatGPT by 24.2% (p < 0.001) and Google Bard by 26.2% (p < 0.001). In the categorical analysis by level of thinking, GPT-4 correctly answered 79.7% of the lower-order questions, which was significantly higher than ChatGPT or Google Bard (p < 0.001). The categorical analysis by question pattern revealed GPT-4's superiority over ChatGPT (67.4% vs. 46.5%, p = 0.004) and Google Bard (39.5%, p < 0.001) in the single-answer questions. The categorical analysis by topic revealed that GPT-4 outperformed ChatGPT (40%, p = 0.013) and Google Bard (26.7%, p = 0.004). No significant differences were observed between the LLMs in the categories not mentioned above. The performance of GPT-4 was significantly better in nuclear medicine (93.3%) than in diagnostic radiology (55.8%; p < 0.001). GPT-4 also performed better on lower-order questions than on higher-order questions (79.7% vs. 45.5%, p < 0.001). CONCLUSION: ChatGPTplus based on GPT-4 scored 65% when answering Japanese questions from the JRBE, outperforming ChatGPT and Google Bard. This highlights the potential of using LLMs to address advanced clinical questions in the field of radiology in Japan.

Application of Texture and Volume Model Analysis to Dedicated Axillary High-resolution 3D T2-weighted MR Imaging: A Novel Method for Diagnosing Lymph Node Metastasis in Patients with Clinically Node-negative Breast Cancer.

PURPOSE: To evaluate the effectiveness of the texture analysis of axillary high-resolution 3D T2-weighted imaging (T2WI) in distinguishing positive and negative lymph node (LN) metastasis in patients with clinically node-negative breast cancer. METHODS: Between December 2017 and May 2021, 242 consecutive patients underwent high-resolution 3D T2WI and were classified into the training (n = 160) and validation cohorts (n = 82). We performed manual 3D segmentation of all visible LNs in axillary level I to extract the texture features. As the additional parameters, the number of the LNs and the total volume of all LNs for each case were calculated. The least absolute shrinkage and selection operator algorithm and Random Forest were used to construct the models. We constructed the texture model using the features from the LN with the largest least axis length in the training cohort. Furthermore, we constructed the 3 models combining the selected texture features of the LN with the largest least axis length, the number of LNs, and the total volume of all LNs: texture-number model, texture-volume model, and texture-number-volume model. As a conventional method, we manually measured the largest cortical diameter. Moreover, we performed the receiver operating curve analysis in the validation cohort and compared area under the curves (AUCs) of the models. RESULTS: The AUCs of the texture model, texture-number model, texture-volume model, texture-number-volume model, and conventional method in the validation cohort were 0.7677, 0.7403, 0.8129, 0.7448, and 0.6851, respectively. The AUC of the texture-volume model was higher than those of other models and conventional method. The sensitivity, specificity, positive predictive value, and negative predictive value of the texture-volume model were 90%, 69%, 49%, and 96%, respectively. CONCLUSION: The texture-volume model of high-resolution 3D T2WI effectively distinguished positive and negative LN metastasis for patients with clinically node-negative breast cancer.

A case of percutaneous transhepatic portal vein stenting without using iodinated contrast media for post pancreatectomy portal vein obstruction.

Postoperative portal vein obstruction could occur as a complication of portal vein reconstruction during hepatic lobectomy or pancreaticoduodenectomy. We report a case of patient with postoperative portal vein obstruction treated with percutaneous transhepatic portal vein stenting without using iodinated contrast media owing to a history of severe allergic reactions. Under ultrasound guidance, carbon dioxide angiography, and appropriate device selection, successful stenting was achieved without serious adverse events. After the operation, portal vein blood flow and clinical symptoms improved, enabling adjuvant chemotherapy. To the best of our knowledge, this is the first case report wherein percutaneous transhepatic portal vein stenting was successfully performed in a patient with an iodine allergy.