Deep learning-based iodine contrast-augmenting algorithm for low-contrast-dose liver CT to assess hypovascular hepatic metastasis.

PURPOSE: To investigate the image quality and diagnostic performance of low-contrast-dose liver CT using a deep learning-based iodine contrast-augmenting algorithm (DLICA) for hypovascular hepatic metastases. METHODS: This retrospective study included 128 patients who underwent contrast-enhanced dual-energy CT for hepatic metastasis surveillance between July 2019 and June 2022 using a 30% reduced iodine contrast dose in the portal phase. Three image types were reconstructed: 50-keV virtual monoenergetic images (50-keV VMI); linearly blended images simulating 120-kVp images (120-kVp); and post-processed 120-kVp images using DLICA (DLICA 120-kVp). Three reviewers evaluated lesion conspicuity, image contrast, and subjective image noise. We also measured image noise, contrast-to-noise ratios (CNRs), and signal-to-noise ratios (SNRs). The diagnostic performance for hepatic metastases was evaluated using a jackknife alternative free-response receiver operating characteristic method with the consensus of two independent radiologists as the reference standard. RESULTS: DLICA 120-kVp demonstrated significantly higher CNR of lesions to liver (5.7 ± 3.1 vs. 3.8 ± 2.1 vs. 3.8 ± 2.1) and higher SNR compared with 50-keV VMI and 120-kVp (p < 0.001 for all). DLICA 120-kVp had significantly lower image noise than 50-kVp VMI for all regions (p < 0.001 for all). DLICA 120-kVp also exhibited superior lesion conspicuity (4.0 [3.3-4.3] vs. 3.7 [3.0-4.0] vs. 3.7 [3.0-4.0]), higher image contrast, and lower subjective image noise compared with 50-keV VMI and 120-kVp (p < 0.001 for all). Although there was no significant difference in the figure of merit for lesion diagnosis among the three methods (p = 0.11), DLICA 120-kVp had a significantly higher figure of merit for lesions with a diameter < 20 mm than 50-keV VMI (0.677 vs. 0.648, p = 0.007). On a per-lesion basis, DLICA 120-kVp also demonstrated higher sensitivity than the 50-keV VMI (81.2% vs. 72.9%, p < 0.001). The specificities per lesion were not significantly different among the three algorithms (p = 0.15). CONCLUSION: DLICA at 120-kVp provided superior lesion conspicuity and image quality and similar diagnostic performance for hypovascular hepatic metastases compared with 50-keV VMI.

Early Postoperative Fever and Atelectasis in Patients Undergoing Upper Abdominal Surgery.

BACKGROUND: Atelectasis is a common complication after upper abdominal surgery and considered as a cause of early postoperative fever (EPF) within 48 hours after surgery. However, the pathophysiologic mechanism of how atelectasis causes fever remains unclear. STUDY DESIGN: Data for adult patients who underwent elective major upper abdominal surgery under general anesthesia at Seoul National University Hospital between January and December of 2021 were retrospectively analyzed. The primary outcome was the association between fever and atelectasis within 2 days after surgery. RESULTS: Of 1,624 patients, 810 patients (49.9%) developed EPF. The incidence of atelectasis was similar between the fever group and the no-fever group (51.6% vs 53.9%, p = 0.348). Multivariate analysis showed no significant association between atelectasis and EPF. Culture tests (21.7% vs 8.8%, p < 0.001) and prolonged use of antibiotics (25.9% vs 13.9%, p < 0.001) were more frequent in the fever group compared to the no-fever group. However, the frequency of bacterial growth on culture tests and postoperative pulmonary complications within 7 days were similar between the two groups. CONCLUSIONS: EPF after major upper abdominal surgery was not associated with radiologically detected atelectasis. EPF also was not associated with the increased risk of postoperative pulmonary complications, bacterial growth on culture studies, or prolonged length of hospital stay.

Volumetric CT Texture Analysis of Intrahepatic Mass-Forming Cholangiocarcinoma for the Prediction of Postoperative Outcomes: Fully Automatic Tumor Segmentation Versus Semi-Automatic Segmentation.

OBJECTIVE: To determine whether volumetric CT texture analysis (CTTA) using fully automatic tumor segmentation can help predict recurrence-free survival (RFS) in patients with intrahepatic mass-forming cholangiocarcinomas (IMCCs) after surgical resection. MATERIALS AND METHODS: This retrospective study analyzed the preoperative CT scans of 89 patients with IMCCs (64 male; 25 female; mean age, 62.1 years; range, 38-78 years) who underwent surgical resection between January 2005 and December 2016. Volumetric CTTA of IMCCs was performed in late arterial phase images using both fully automatic and semi-automatic liver tumor segmentation techniques. The time spent on segmentation and texture analysis was compared, and the first-order and second-order texture parameters and shape features were extracted. The reliability of CTTA parameters between the techniques was evaluated using intraclass correlation coefficients (ICCs). Intra- and interobserver reproducibility of volumetric CTTAs were also obtained using ICCs. Cox proportional hazard regression were used to predict RFS using CTTA parameters and clinicopathological parameters. RESULTS: The time spent on fully automatic tumor segmentation and CTTA was significantly shorter than that for semi-automatic segmentation: mean ± standard deviation of 1 minutes 37 seconds ± 50 seconds vs. 10 minutes 48 seconds ± 13 minutes 44 seconds (p < 0.001). ICCs of the texture features between the two techniques ranged from 0.215 to 0.980. ICCs for the intraobserver and interobserver reproducibility using fully automatic segmentation were 0.601-0.997 and 0.177-0.984, respectively. Multivariable analysis identified lower first-order mean (hazard ratio [HR], 0.982; p = 0.010), larger pathologic tumor size (HR, 1.171; p < 0.001), and positive lymph node involvement (HR, 2.193; p = 0.014) as significant parameters for shorter RFS using fully automatic segmentation. CONCLUSION: Volumetric CTTA parameters obtained using fully automatic segmentation could be utilized as prognostic markers in patients with IMCC, with comparable reproducibility in significantly less time compared with semi-automatic segmentation.

Case report of juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome: first report in Korea with a novel mutation in the SMAD4 gene.

Juvenile polyposis/hereditary hemorrhagic telangiectasia (JPS/HHT) syndrome is a rare, autosomal dominant disorder caused by mutations in the SMAD4 gene, presenting with features of both juvenile polyposis syndrome (JPS) and HHT. Reports and studies of JPS/HHT syndrome are mostly from Western countries, while there are scarce reports from East Asian countries. We report a case of a Korean boy who had been previously diagnosed with JPS at 7 years and had first visited to our center at 15 years of age. Genetic studies of the patient and parents revealed a novel variant in the SMAD4 gene, SMAD4 c.1146_1163del; p.His382_Val387del (NM_005359.5), which had developed de novo. Numerous pedunculated and sessile polyps were observed throughout the gastrointestinal (GI) tract. Mucocutaneous telangiectases were observed on the lips, tongue, and jejunum, and arteriovenous malformations (AVMs) were observed in both lungs. This is the first case report of JPS/HHT syndrome in Korea, with a novel deletion variant in the SMAD4 gene. Patients with JPS should undergo genetic evaluation of associated genes including SMAD4, and those with genetically confirmed SMAD4 variants should undergo further evaluation for coexisting asymptomatic AVMs in order to prevent life-threatening complications of thrombotic emboli and pulmonary hemorrhage.

Clinical outcomes of patients with a high alpha-fetoprotein level but without evident recurrence on CT or MRI in surveillance after curative-intent treatment for hepatocellular carcinoma.

PURPOSE: Multiphasic CT or MRI and serum alpha-fetoprotein (AFP) are widely used for posttreatment surveillance of hepatocellular carcinoma (HCC). This study aimed to investigate the clinical outcomes of patients with high posttreatment AFP but without evident recurrence on CT or MRI after curative-intent treatment of HCC. METHODS: We retrospectively analyzed 121 patients presenting with high posttreatment AFP (> 20 ng/mL) without evident recurrence on multiphasic CT or MRI during surveillance after curative-intent surgical resection or radiofrequency ablation (RFA) for HCC. The time interval from the first event of high posttreatment AFP to imaging-evident recurrence (TimeAFP-Imaging recurrence) was estimated using the Kaplan-Meier method. Cox regression analyses were performed to assess the associated factors with TimeAFP-Imaging recurrence. RESULTS: The median TimeAFP-Imaging recurrence was 20.0 months (95% CI 13.0-28.0 months), and the estimated 6-month and 1-year cumulative incidences of imaging-evident recurrence were 24.4% and 40.1%, respectively. In multivariate Cox analyses, late onset of AFP elevation (> 3 months after treatment) was an independent predictor of shorter TimeAFP-Imaging recurrence (HR 2.11, P = 0.015) if using variables available at the first event of AFP elevation, while non-normalization of AFP at the next follow-up was an independent predictor of shorter TimeAFP-Imaging recurrence (HR 3.65, P < 0.001) if using variables including the follow-up data. CONCLUSION: In the surveillance setting after curative-intent treatment of HCC, patients presenting with high posttreatment AFP without evident recurrence on CT or MRI may frequently progress to imaging-evident recurrence. In high-risk patients, an extensive diagnostic workup or close monitoring is needed to detect HCC recurrence earlier.

Subtherapeutic Infliximab Trough Levels and Complete Mucosal Healing Are Associated With Sustained Clinical Remission After Infliximab Cessation in Paediatric-onset Crohn's Disease Patients Treated With Combined Immunosuppressive Therapy.

BACKGROUND AND AIMS: We aimed to investigate the outcome in paediatric-onset Crohn's disease patients who had discontinued infliximab after maintaining clinical remission with combined immunosuppression, and to determine factors associated with clinical relapse. METHODS: We conducted a retrospective observational study of 63 paediatric-onset Crohn's disease patients who had stopped scheduled infliximab during sustained corticosteroid-free clinical remission for at least 1 year with infliximab and azathioprine, and were followed up for at least 1 year thereafter. Cumulative relapse rates and the median time to relapse were estimated statistically. Factors at cessation were also evaluated for their association with clinical relapse. RESULTS: After a median follow-up period of 4.3 years [range, 1-7.5 years], 60.3% [38/63] of patients had experienced clinical relapse. According to Kaplan-Meier survival analysis, the estimated cumulative relapse rates at 1, 4, and 6 years were 19.0%, 62.2%, and 75.2%, respectively, and the median relapse time was 3.3 years from infliximab cessation. According to multivariate Cox proportional hazard regression analysis, infliximab trough levels of ≥2.5 µg/mL and incomplete mucosal healing were associated with clinical relapse (hazard ratio [HR] = 7.199, 95% confidence interval [CI] = 1.641-31.571, p = 0.009 and HR = 3.628, 95% CI = 1.608-8.185, p = 0.002, respectively). Although re-treatment with infliximab was effective in 90.9% [30/33] of patients, 7.9% [3/38] eventually underwent surgery within 1 year of relapse. CONCLUSIONS: Considering the high cumulative relapse rates in the long term and cases of severe relapse requiring surgery, discontinuing infliximab in paediatric-onset Crohn's disease patients is currently inadvisable. However, there may be a subgroup of patients who are good candidates for infliximab withdrawal.

Characteristics of Upper Gastrointestinal Tract Involvement in Korean Pediatric Crohn's Disease: A Multicenter Study.

PURPOSE: Crohn's disease (CD) can involve any site of the gastrointestinal tract (GIT). However, the characteristics of upper GIT involvement in CD are unclear, especially in the Eastern pediatric population. This study aimed to estimate the prevalence of upper GIT involvement and identify the clinical features of Korean children with CD. METHODS: This was a retrospective multicenter cohort study that included 52 pediatric patients with CD who underwent esophagogastroduodenoscopy and biopsy. The clinical symptoms and endoscopic and histologic features of the upper GIT were identified according to the presence or absence of upper gastrointestinal symptoms. RESULTS: Among the 52 patients, upper GIT involvement was noted in 50.0% (26/52). The mean age at CD diagnosis was 14.1±2.1 years. Gastric ulcer was the most common lesion (19.2%) found on upper GIT endoscopy, followed by duodenal ulcers (15.4%). Chronic inflammation was the most common histopathologic feature (75.0%), followed by gastric erosion (17.3%). Granuloma was found in 9.6% of patients. Helicobacter pylori infection was identified in 5.8% of patients. Endoscopic and histologic findings were not significantly different, but the mean values of erythrocyte sedimentation rate (60.7±27.1 vs. 43.0±27.6 mm/h, p=0.037) and C-reactive protein (16.5±28.2 vs. 6.62±13.4 mg/dL, p=0.014) were significantly different between patients with and without upper gastrointestinal CD symptoms. CONCLUSION: Upper GIT involvement was relatively common in pediatric patients with CD irrespective of upper gastrointestinal symptoms, and H. pylori infection was relatively uncommon. The results of this study should aid the establishment of regional guidelines for upper GIT examination.