Publications by authors named "Seung Soo Lee"

229 Publications

Deep learning-based algorithm to detect primary hepatic malignancy in multiphase CT of patients at high risk for HCC.

Eur Radiol 2021 Mar 18. Epub 2021 Mar 18.

Department of Convergence Medicine, Asan Medical Institute of Convergence Science and Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Objectives: To develop and evaluate a deep learning-based model capable of detecting primary hepatic malignancies in multiphase CT images of patients at high risk for hepatocellular carcinoma (HCC).

Methods: A total of 1350 multiphase CT scans of 1280 hepatic malignancies (1202 HCCs and 78 non-HCCs) in 1320 patients at high risk for HCC were retrospectively analyzed. Following the delineation of the focal hepatic lesions according to reference standards, the CT scans were categorized randomly into the training (568 scans), tuning (193 scans), and test (589 scans) sets. Multiphase CT information was subjected to multichannel integration, and livers were automatically segmented before model development. A deep learning-based model capable of detecting malignancies was developed using a mask region-based convolutional neural network. The thresholds of the prediction score and the intersection over union were determined on the tuning set corresponding to the highest sensitivity with < 5 false-positive cases per CT scan. The sensitivity and the number of false-positives of the proposed model on the test set were calculated. Potential causes of false-negatives and false-positives on the test set were analyzed.

Results: This model exhibited a sensitivity of 84.8% with 4.80 false-positives per CT scan on the test set. The most frequent potential causes of false-negatives and false-positives were determined to be atypical enhancement patterns for HCC (71.7%) and registration/segmentation errors (42.7%), respectively.

Conclusions: The proposed deep learning-based model developed to automatically detect primary hepatic malignancies exhibited an 84.8% of sensitivity with 4.80 false-positives per CT scan in the test set.

Key Points: • Image processing, including multichannel integration of multiphase CT and automatic liver segmentation, enabled the application of a deep learning-based model to detect primary hepatic malignancy. • Our model exhibited a sensitivity of 84.8% with a false-positive rate of 4.80 per CT scan.
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http://dx.doi.org/10.1007/s00330-021-07803-2DOI Listing
March 2021

Inter-reader reliability of CT Liver Imaging Reporting and Data System according to imaging analysis methodology: a systematic review and meta-analysis.

Eur Radiol 2021 Mar 13. Epub 2021 Mar 13.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-Ro 43-Gil, Songpa-Gu, Seoul, 05505, Republic of Korea.

Objectives: To establish inter-reader reliability of CT Liver Imaging Reporting and Data System (LI-RADS) and explore factors that affect it.

Methods: MEDLINE and EMBASE databases were searched from January 2014 to March 2020 to identify original articles reporting the inter-reader reliability of CT LI-RADS. The imaging analysis methodology of each study was identified, and pooled intraclass correlation coefficient (ICC) or kappa values (κ) were calculated for lesion size, major features (arterial-phase hyperenhancement [APHE], nonperipheral washout [WO], and enhancing capsule [EC]), and LI-RADS categorization (LR) using random-effects models. Subgroup analyses of pooled κ were performed for the number of readers, average reader experience, differences in reader experience, and LI-RADS version.

Results: In the 12 included studies, the pooled ICC or κ of lesion size, APHE, WO, EC, and LR were 0.99 (0.96-1.00), 0.69 (0.58-0.81), 0.67 (0.53-0.82), 0.65 (0.54-0.76), and 0.70 (0.59-0.82), respectively. The experience and number of readers varied: studies using readers with ≥ 10 years of experience showed significantly higher κ for LR (0.82 vs. 0.45, p = 0.01) than those with < 10 years of reader experience. Studies with multiple readers including inexperienced readers showed significantly lower κ for APHE (0.55 vs. 0.76, p = 0.04) and LR (0.45 vs. 0.79, p = 0.02) than those with all experienced readers.

Conclusions: CT LI-RADS showed substantial inter-reader reliability for major features and LR. Inter-reader reliability differed significantly according to average reader experience and differences in reader experience. Reported results for inter-reader reliability of CT LI-RADS should be understood with consideration of the imaging analysis methodology.

Key Points: • The CT Liver Imaging Reporting and Data System (LI-RADS) provides substantial inter-reader reliability for three major features and category assignment. • The imaging analysis methodology varied across studies. • The inter-reader reliability of CT LI-RADS differed significantly according to the average reader experience and the difference in reader experience.
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http://dx.doi.org/10.1007/s00330-021-07815-yDOI Listing
March 2021

Radiomics and deep learning in liver diseases.

J Gastroenterol Hepatol 2021 Mar;36(3):561-568

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.

Recently, radiomics and deep learning have gained attention as methods for computerized image analysis. Radiomics and deep learning can perform diagnostic or predictive tasks using high-dimensional image-derived features and have the potential to expand the capabilities of liver imaging beyond the scope of traditional visual image analysis. Recent research has demonstrated the potential of these techniques in various fields of liver imaging, including staging of liver fibrosis, prognostication of malignant liver tumors, automated detection and characterization of liver tumors, automated abdominal organ segmentation, and body composition analysis. However, because most of the previous studies were preliminary and focused mainly on technical feasibility, further clinical validation is required for the application of radiomics and deep learning in clinical practice. In this review, we introduce the technical aspects of radiomics and deep learning and summarize the recent studies on the application of these techniques in liver radiology.
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http://dx.doi.org/10.1111/jgh.15414DOI Listing
March 2021

Impact of Palliative Gastrectomy in Patients with Incurable Gastric Cancer.

Medicina (Kaunas) 2021 Feb 26;57(3). Epub 2021 Feb 26.

Department of Surgery, School of Medicine, Kyungpook National University, Daegu 41944, Korea.

: The prognosis of metastatic or unresectable gastric cancer is dismal, and the benefits of the palliative resection of primary tumors with noncurative intent remain controversial. This study aimed to evaluate the impact of palliative gastrectomy (PG) on overall survival in gastric cancer patients. : One hundred forty-eight gastric cancer patients who underwent PG or a nonresection (NR) procedure between January 2011 and 2017 were retrospectively reviewed to select and analyze clinicopathological factors that affected prognosis. : Fifty-five patients underwent primary tumor resection with palliative intent, and 93 underwent NR procedures owing to the presence of metastatic or unresectable disease. The PG group was younger and more female dominant. In the PG group, R1 and R2 resection were performed in two patients (3.6%) and 53 patients (96.4%), respectively. The PG group had a significantly longer median overall survival than the NR group (28.4 vs. 7.7 months, < 0.001). Multivariate analyses revealed that the overall survival was significantly better after palliative resection (hazard ratio (HR), 0.169; 95% confidence interval (CI), 0.088-0.324; < 0.001) in patients with American Society of Anesthesiologists Physical Status (ASA) scores ≤1 (HR, 0.506; 95% CI, 0.291-0.878; = 0.015) and those who received postoperative chemotherapy (HR, 0.487; 95% CI, 0.296-0.799; = 0.004). Among the patients undergoing palliative resection, the presence of <15 positive lymph nodes was the only significant predictor of better overall survival (HR, 0.329; 95% CI, 0.121-0.895; = 0.030). : PG might lead to the prolonged survival of certain patients with incurable gastric cancer, particularly those with less-extensive lymph-node metastasis.
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http://dx.doi.org/10.3390/medicina57030198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996496PMC
February 2021

Valorization of waste-cooking oil into sophorolipids and application of their methyl hydroxyl branched fatty acid derivatives to produce engineering bioplastics.

Waste Manag 2021 Apr 22;124:195-202. Epub 2021 Feb 22.

Research Center for Chemical Biotechnology, Korea Research Institute of Chemical Technology (KRICT), 406-30, Jongga-ro, Ulsan 44429, Republic of Korea; Advanced Materials and Chemical Engineering, University of Science and Technology (UST), Daejeon 34113, Republic of Korea. Electronic address:

Waste-cooking oil (WCO) is defined as vegetable oil that has been used to fry food at high temperatures. The annual global generation of WCO is 41-67 million tons. Without proper treatment, most WCO is abandoned in sinks and the solid residue of WCO is disposed of in landfills, resulting in serious environmental problems. Recycling and valorizing WCO have received considerable attention to reduce its negative impact on ecosystems. To convert WCO into a high value-added compound, we aimed to produce sophorolipids (SLs) that are industrially important biosurfactants, using WCO as a hydrophobic substrate by the fed-batch fermentation of Starmerella bombicola. The SLs concentration was increased ~3.7-fold compared with flask culture (315.6 vs. 84.8 g/L), which is the highest value ever generated from WCO. To expand the applications of SLs, we prepared methyl hydroxy branched fatty acids (MHBFAs) from SLs, which are important chemicals for various industries yet difficult to produce by chemical methods, using a bio-chemical hybrid approach. We synthesized bio-based plastics using MHBFAs as co-monomers. Compared with the control polymer without MHBFAs, even the incorporation of 1 mol% into polymer chains improved mechanical properties (such as ultimate tensile strength, 1.1-fold increase; toughness, 1.3-fold increase). To the best of our knowledge, this is the first attempt to apply MHBFAs from SLs derived from WCO to building blocks of plastics. Thus, we extended the valorization areas of WCO to one of the world's largest industries.
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http://dx.doi.org/10.1016/j.wasman.2021.02.003DOI Listing
April 2021

Microfluidic ultrafine particle dosimeter using an electrical detection method with a machine-learning-aided algorithm for real-time monitoring of particle density and size distribution.

Lab Chip 2021 Feb 25. Epub 2021 Feb 25.

School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.

Growing concerns related to the adverse health effects of airborne ultrafine particles (UFPs; particles smaller than 300 nm) have highlighted the need for field-portable, cost-efficient, real-time UFP dosimeters to monitor individual exposure. These dosimeters must measure both the particle density and size distribution as these parameters are essential to the determination of where and how many UFPs will be deposited in human lungs. However, though various kinds of laboratory-grade instruments and hand-held monitors have been developed, they are expensive and only capable of measuring particle size distribution. A microfluidic UFP dosimeter is proposed in this study to address these limitations. The proposed sensor, based on an electrical detection method with a machine-learning-aided algorithm, can simultaneously measure the size distribution (number concentration, mean mobility diameter, geometric standard deviation) and particle density, and is compact owing to the microelectromechanical systems (MEMS) technology. In a comparison test using physically synthesised Ag and di-ethyl-hexyl sebacate (DEHS) aerosols, the mean measurement errors of the proposed sensor compared to the reference system were 6.1%, 4.5%, and 7.3% for number concentration, mean mobility diameter, and particle density, respectively. Moreover, when the machine-learning aided algorithm was operated, the geometric standard deviation could be deduced with a 7.6% difference. These results indicate that the proposed device can be successfully used as a field-portable UFP sensor to assess individual exposure, an on-site monitor for ambient air pollution, an analysis tool in toxicological studies of inhaled particles, for quality assurance of nanomaterials engineered via aerosol synthesis, etc.
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http://dx.doi.org/10.1039/d0lc01240hDOI Listing
February 2021

Combined Hepatocellular-Cholangiocarcinoma: Magnetic Resonance Imaging Features and Prognosis According to Risk Factors for Hepatocellular Carcinoma.

J Magn Reson Imaging 2021 Feb 9. Epub 2021 Feb 9.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.

Background: Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) can develop in patients with and without risk factors for hepatocellular carcinoma (HCC).

Purpose: To compare the clinical and magnetic resonance imaging (MRI) characteristics of cHCC-CCA in patients with and without risk factors for HCC, and to assess the influence of risk factors on patient prognosis.

Study Type: Retrospective.

Population: A total of 152 patients with surgically confirmed cHCC-CCA.

Field Strength/sequence: 1.5-T and 3-T/T1-weighted dual gradient-echo in- and opposed-phase, T2-weighted turbo-spin-echo, diffusion-weighted single-shot spin-echo echo-planar, and T1-weighted three-dimensional gradient-echo contrast-enhanced sequences.

Assessment: MRI features according to the Liver Imaging Reporting and Data System (LI-RADS) and pathologic findings based on revised classification were compared between patients with and without risk factors for HCC. Overall survival (OS) and recurrence-free survival (RFS) were also compared between the two groups, and factors associated with survival were evaluated.

Statistical Tests: The clinico-pathologic and MRI features of the two groups were compared using Student's t-tests, Mann-Whitney U-tests, and chi-square tests. OS and RFS were evaluated by the Kaplan-Meier method, and factors associated with survival were evaluated by Cox proportional hazard model.

Results: cHCC-CCA in patients with risk factors were more frequently classified as LI-RADS category 4 or 5 (LR-4/5; probably or definitely HCC) (48.7%), whereas those without risk factors were more frequently classified as category M (LR-M; probably malignant, not specific for HCC) (63.6%). RFS and OS did not differ significantly according to risk factors (P = 0.63 and 0.83). Multivariable analysis showed that pathologic tumor type (hazard ratio 2.02; P < 0.05) and LI-RADS category (hazard ratio 2.19; P < 0.05) were significantly associated with RFS and OS, respectively.

Data Conclusion: Although MRI features of cHCC-CCA differed significantly between patients with and without risk factors for HCC, postsurgical prognosis did not. LI-RADS category and pathologic tumor type were independently correlated with postsurgical prognosis in patients with cHCC-CCA.

Level Of Evidence: 3 TECHNICAL EFFICACY STAGE: 2.
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http://dx.doi.org/10.1002/jmri.27528DOI Listing
February 2021

Effectiveness of early endoscopic ultrasound-guided drainage for postoperative fluid collection.

Surg Endosc 2021 Jan 28. Epub 2021 Jan 28.

Department of Gastroenterology, Asan Medical Center, University of Ulsan College of Medicine, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, Korea.

Background: Postoperative abdominal fluid collections (PAFCs) are a potentially fatal complication of pancreatobiliary surgery. Endoscopic ultrasound (EUS)-guided drainage has recently been shown to be effective in treating PAFCs of more than 4 weeks old. Little is currently known, however, regarding the EUS-guided drainage of PAFCs of less than 4 weeks. This study assessed the efficacy and safety of the early drainage (< 4 weeks) of PAFCs via EUS guidance.

Methods: The data of patients who had undergone EUS-guided PAFC drainage between July 2008 and January 2018 were retrospectively analyzed. Data of EUS-guided PAFC drainage were obtained from prospectively collected EUS database of our institute and reviewed of patients' clinical parameters based on electrical medical record.

Results: A total of 48 patients who had undergone EUS-guided PAFC drainage within 4 weeks of pancreatobiliary surgery were enrolled. The indications of procedure included abdominal pain (n = 27), fever (n = 18), leukocytosis (n = 2), and increased size of PAFC during external tube drainage (n = 1). Technical success was achieved in all cases, and the clinical success rate was 95.8% (46/48). Four patients underwent secondary procedures. The median period from surgery to EUS-guide drainage was 14 days (Interquartile range [IQR] 10-16), and median time to resolution was 23.5 days (IQR 8.5-33.8). Adverse events occurred in two cases that were developed intracystic bleeding and were successfully resolved by arterial coil embolization.

Conclusions: Early EUS-guided drainage is a technically feasible, effective, and safe method in patients who have developing PAFCs within 4 weeks of pancreatobiliary surgery.
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http://dx.doi.org/10.1007/s00464-020-08247-3DOI Listing
January 2021

Diagnostic performance of ultrasonography-guided core-needle biopsy according to MRI LI-RADS diagnostic categories.

Ultrasonography 2020 Nov 3. Epub 2020 Nov 3.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Purpose: According to the American Association for the Study of Liver Diseases (AASLD) guidelines, biopsy is a diagnostic option for focal hepatic lesions depending on the Liver Imaging Reporting and Data System (LI-RADS) category. We evaluated the diagnostic performance of ultrasonography-guided core-needle biopsy (CNB) according to LI-RADS categories.

Methods: High-risk patients for hepatocellular carcinoma (HCC) who underwent magnetic resonance imaging (MRI) followed by CNB for a focal hepatic lesion preoperatively were retrospectively enrolled. Focal hepatic lesions on MRI were evaluated according to LI-RADS version 2018. Pathologic results were categorized into HCC, non-HCC malignancies, and benignity. The categorization was defined as correct when the CNB pathology and surgical pathology reports were identical. Nondiagnostic results were defined as inadequate CNB pathology findings for a specific diagnosis. The proportion of correct categorizations was calculated for each LI-RADS category, excluding nondiagnostic results.

Results: After excluding 16 nondiagnostic results, 131 lesions were analyzed (45 LR-5, 24 LR-4, 4 LR-3, and 58 LR-M). All LR-5 lesions were HCC, and CNB correctly categorized 97.8% (44/45) of LR-5 lesions. CNB correctly categorized all 24 LR-4 lesions, 16.7% (4/24) of which were non-HCC malignancies. All LR-M lesions were malignant, and 62.1% (36/58) were non-HCC malignancies. CNB correctly categorized 93.1% (54/58) of LR-M lesions, and 12.5% (3/24) of lesions with CNB results of HCC were confirmed as non-HCC malignancies.

Conclusion: In agreement with AASLD guidelines, CNB could be helpful for LR-4 lesions, but is unnecessary for LR-5 lesions. In LR-M lesions, CNB results of HCC did not exclude non-HCC malignancy.
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http://dx.doi.org/10.14366/usg.20110DOI Listing
November 2020

Monitoring the Effective Density of Airborne Nanoparticles in Real Time Using a Microfluidic Nanoparticle Analysis Chip.

ACS Sens 2021 01 6;6(1):137-147. Epub 2021 Jan 6.

School of Mechanical Engineering, Yonsei University, Seoul 03722, Republic of Korea.

Determining the effective density of airborne nanoparticles (NPs; particles smaller than 100 nm in diameter) at a point of interest is essential for toxicology and environmental studies, but it currently requires complex analysis systems comprising several high-precision instruments as well as a specially trained operator. To address these limitations, a field-portable and cost-efficient microfluidic NP analysis device is presented, which provides quantitative information on the effective density and size distribution of NPs in real time. Unlike conventional analysis systems, the device can operate in a standalone mode because of the chip operating principle based on the electrostatic/inertial classification and electrical detection methods. Moreover, the device is both compact (16.0 × 10.9 × 8.6 cm) and light (950 g) owing to the hardware strip down enabled by integrating the essential functions for effective density analysis on a single chip. Quantitative experiments performed to simulate real-life applications utilizing effective density (i.e., effective density-based morphology analysis on engineered NPs and multi-parametric NP monitoring in ambient air) demonstrate that the developed device can be used as an analysis tool in toxicological studies as an on-site sensor for the monitoring of individual NP exposure and environments, for quality monitoring of engineered NPs via aerosol synthesis, and other applications.
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http://dx.doi.org/10.1021/acssensors.0c01986DOI Listing
January 2021

Retrospective analysis of current guidelines for hepatocellular carcinoma diagnosis on gadoxetic acid-enhanced MRI in at-risk patients.

Eur Radiol 2021 Jan 3. Epub 2021 Jan 3.

Division of Abdominal Radiology, Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Objective: To evaluate and compare the diagnostic performance of the updated HCC guidelines using gadoxetic acid-enhanced MRI.

Methods: In this study, patients at risk of HCC who underwent gadoxetic acid-enhanced MRI following US/CT surveillance were retrospectively recruited from 3 centers. Three radiologists independently evaluated hepatic nodule imaging features relevant to the diagnostic criteria outlined in each guideline. Per-lesion sensitivity, specificity, and accuracy were compared between guidelines using logistic regression with a generalized estimating equation. Inter-observer agreements on imaging features were determined using Fless κ statistics.

Results: Altogether, 447 nodules (310 HCCs, 20 combined hepatocellular-cholangiocarcinomas, 2 cholangiocarcinomas, and 115 benign entities) measuring 1-3 cm from 386 patients were assessed. The KLCA-NCC and APASL guidelines showed the highest sensitivity (82.3-90.6%, p < .001) and accuracy (83.9-88.6%) among the five guidelines. The OPTN/UNOS guideline showed the highest specificity (94.9-97.1%), followed by the AASLD/LI-RADS, EASL, KLCA-NCC, and APASL guidelines, with significant difference only with the APASL guideline. The diagnostic performance of the updated AASLD/LI-RADS and EASL guidelines and of the KLCA-NCC and APASL guidelines was comparable (p > .05). Inter-observer agreement was substantial to almost perfect (κ = 0.73-0.87).

Conclusions: For the diagnosis of HCC using gadoxetic acid-enhanced MRI, the KLCA-NCC and APASL guidelines showed the highest sensitivity and accuracy. The OPTN/UNOS guideline showed the highest specificity. Acknowledging their relative strengths and weaknesses could help adapt the diagnostic criteria according to the clinical context.

Key Points: • APASL and KLCA-NCC provided significantly the highest sensitivity and accuracy, followed by AASLD/LI-RADS and EASL in an endemic area for hepatitis B. • OPTN/UNOS showed the highest specificity, followed by AASLD/LI-RADS, EASL, KLCA-NCC, and APASL guidelines, with significant difference only with APASL. • Broadened definition of arterial hyperenhancement, washout, and the size of the lesion eligible to apply diagnostic criteria may improve the diagnostic performance for HCC in an endemic area for hepatitis B.
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http://dx.doi.org/10.1007/s00330-020-07577-zDOI Listing
January 2021

PD-L1 Targeting Immune-Microbubble Complex Enhances Therapeutic Index in Murine Colon Cancer Models.

Pharmaceuticals (Basel) 2020 Dec 23;14(1). Epub 2020 Dec 23.

Department of Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea.

Cancer immunotherapy has revolutionized the way different neoplasms are treated. Among the different variations of cancer immunotherapy, the checkpoint inhibitors targeting the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) axis have been validated and are currently used in the clinics. Nevertheless, these therapeutic antibodies are associated with significant side effects and are known to induce immune-related toxicities. To address these issues, we have developed an immune-microbubble complex (IMC) which not only reduces the toxicities associated with the antibodies but also enhances the therapeutic efficacy when combined with focused ultrasound. The concept of IMCs could be applied to any type of antibody-based treatment regimens to maximize their therapeutic potential.
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http://dx.doi.org/10.3390/ph14010006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7822446PMC
December 2020

Interobserver Reproducibility in Sonographic Measurement of Diameter and Volume of Papillary Thyroid Microcarcinoma.

Thyroid 2021 03 18;31(3):452-458. Epub 2021 Jan 18.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Active surveillance is recommended as an alternative to immediate surgery for low-risk papillary thyroid microcarcinoma (PTMC), and determining meaningful changes in diameter and volume on ultrasonography (US) is critical. However, interobserver reproducibility of the sonographic measurement of maximum diameter and volume of PTMC has not been well established. We aimed to determine the reproducibility in the measurement of maximum diameter and volume of PTMC on US. Consecutive patients who underwent US for pathologically proven PTMC between December 2018 and December 2019 were retrospectively reviewed. Two observers independently performed sonographic measurement of each nodule using standardized measurement methods. Each observer measured maximum transverse, anteroposterior, and longitudinal nodule diameters, and using these, nodule volume was calculated using the ellipsoid formula. Interobserver reproducibility in the measurement of the maximum diameter and volume was assessed using percentage reproducibility coefficient (RC). Z-tests of the intraclass correlation coefficients (ICCs) were used to compare the interobserver reproducibility in subgroups defined according to sonographic characteristics, such as the presence of microcalcification, nodule size, and parenchymal heterogeneity. A total of 197 thyroid nodules from 188 patients were included in the study series. The percentage RCs were 71.8% [95% confidence interval, CI 65.4-79.7%] and 23.7% [CI 21.6-26.3%] for volume and maximum diameter measurements, respectively. There were no significant differences noted in the ICC values according to nodule orientation, presence of calcifications, size, or parenchymal heterogeneity. For PTMC, a difference of up to 24% in the maximum diameter and 72% in the volume may be considered to be within measurement error on US. This value may be used to determine the cutoff for defining meaningful change in the maximum diameter and volume for PTMC during active surveillance.
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http://dx.doi.org/10.1089/thy.2020.0317DOI Listing
March 2021

Exergy Analysis of Advanced Adsorption Cooling Cycles.

Entropy (Basel) 2020 Sep 26;22(10). Epub 2020 Sep 26.

Department of Mechanical Engineering, Sejong University, Seoul 05006, Korea.

This study conducted an exergy analysis of advanced adsorption cooling cycles. The possible exergy losses were divided into internal losses and external losses, and the exergy losses of each process in three advanced cycles: a mass recovery cycle, heat recovery cycle and combined heat and mass recovery cycle were calculated. A transient two-dimensional numerical model was used to solve the heat and mass transfer kinetics. The exergy destruction of each component and process in a finned tube type, silica gel/water working paired-adsorption chiller was estimated. The results showed that external loss was significantly reduced at the expense of internal loss. The mass recovery cycle reduced the total loss to 60.95 kJ/kg, which is -2.76% lower than the basic cycle. In the heat recovery cycle, exergy efficiency was significantly enhanced to 23.20%. The optimum value was 0.1248 at a heat recovery time of 60 s. The combined heat and mass recovery cycle resulted in an 11.30% enhancement in exergy efficiency, compared to the heat recovery cycle. The enhancement was much clearer when compared to the basic cycle, with 37.12%. The observed dependency on heat recovery time and heating temperature was similar to that observed for individual mass recovery and heat recovery cycles.
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http://dx.doi.org/10.3390/e22101082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7597169PMC
September 2020

Prediction of transarterial chemoembolization refractoriness in patients with hepatocellular carcinoma using imaging features of gadoxetic acid-enhanced magnetic resonance imaging.

Acta Radiol 2020 Nov 16:284185120971844. Epub 2020 Nov 16.

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Background: Repeated transarterial chemoembolization (TACE) can be associated with loss of its efficacy and subsequent tumor progression.

Purpose: To identify features of gadoxetic acid-enhanced magnetic resonance imaging (MRI) associated with TACE refractoriness and to develop a prediction model for estimating the risk of TACE refractoriness.

Material And Methods: Among 1025 patients with intermediate-stage hepatocellular carcinoma (HCC) who underwent TACE as a first-line treatment during 2010-2017, 427 patients who underwent preoperative gadoxetic acid-enhanced MRI were analyzed. According to the date of initial TACE, patients were divided into the development cohort (n = 211) and the test cohort (n = 216). TACE refractoriness was determined according to the Japan Society of Hepatology guidelines. Univariable and multivariable analyses were performed to investigate the association between clinical/MRI features and TACE refractoriness. The performance of the prediction model was internally and externally assessed using the C-index of discrimination and a Hosmer-Lemeshow goodness-of-fit test for calibration.

Results: By analyzing 427 patients, we constructed a prediction model with the following independent features associated with TACE refractoriness: maximum tumor size; tumor number; peritumoral hypointensity on hepatobiliary phase (HBP); and the presence of non-hypervascular hypointense nodule on HBP. This system enabled the prediction of TACE refractoriness in the development cohort (C-index, 0.796) and the test cohort (C-index, 0.738) with good discrimination and calibration abilities.

Conclusion: The prediction model based on gadoxetic acid-enhanced MRI features in addition to the known predictors including tumor size and number can be used to estimate the risk of TACE refractoriness in patients with intermediate-stage HCC.
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http://dx.doi.org/10.1177/0284185120971844DOI Listing
November 2020

Diagnostic performance of MRI for HCC according to contrast agent type: a systematic review and meta-analysis.

Hepatol Int 2020 Dec 4;14(6):1009-1022. Epub 2020 Nov 4.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.

Background/purpose: Conflicting results have been reported between the use of extracellular contrast agent (ECA) and hepatobiliary contrast agent (HBA) when magnetic resonance imaging (MRI) is used for the diagnosis of hepatocellular carcinoma (HCC). Therefore, we aimed to compare the diagnostic performance of MRI using ECA (ECA-MRI) and HBA (HBA-MRI).

Methods: Original studies reporting the diagnostic performance of contrast-enhanced MRI for the diagnosis of HCC published between January 2010 and February 2020 were identified in a Pubmed, EMBASE, and Cochrane Library database search. The pooled sensitivity and specificity of ECA-MRI and HBA-MRI were calculated using a bivariate random effects model and compared using a joint-model bivariate meta-regression. Subgroup analyses were performed to compare the diagnostic performance of ECA-MRI and HBA-MRI according to study design, underlying liver disease, lesion size, reference standard, and imaging criteria.

Results: Of the 1760 screened articles, 31 studies were included: 15 studies included 2890 lesions imaged using ECA-MRI and 19 studies included 3893 lesions imaged using HBA-MRI. The pooled sensitivity and specificity were not significantly different between ECA-MRI (sensitivity, 72% [95% confidence interval 65-79%]; specificity 92% [89-95%]) and HBA-MRI (76% [68-83%]; 92% [87-95%], p = 0.72). Subgroup analyses did not find differences in diagnostic performance between ECA-MRI and HBA-MRI according to study design (p ≥ 0.11), underlying disease (p ≥ 0.09), lesion size (≤ 2 cm, p = 0.97), reference standard (p = 0.70), or imaging criteria (p = 0.33).

Conclusion: ECA-MRI showed similar performance to HBA-MRI in the diagnosis of HCC. The contrast agent might be selected with consideration of the advantages of each agent.
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http://dx.doi.org/10.1007/s12072-020-10100-7DOI Listing
December 2020

An index based on deep learning-measured spleen volume on CT for the assessment of high-risk varix in B-viral compensated cirrhosis.

Eur Radiol 2021 May 30;31(5):3355-3365. Epub 2020 Oct 30.

Department of Brain and Cognitive Engineering, Korea University, 145 Anam-ro, Anam-dong, Seongbuk-gu, Seoul, 02841, South Korea.

Objectives: Deep learning enables an automated liver and spleen volume measurements on CT. The purpose of this study was to develop an index combining liver and spleen volumes and clinical factors for detecting high-risk varices in B-viral compensated cirrhosis.

Methods: This retrospective study included 419 patients with B-viral compensated cirrhosis who underwent endoscopy and CT from 2007 to 2008 (derivation cohort, n = 239) and from 2009 to 2010 (validation cohort, n = 180). The liver and spleen volumes were measured on CT images using a deep learning algorithm. Multivariable logistic regression analysis of the derivation cohort developed an index to detect endoscopically confirmed high-risk varix. The cumulative 5-year risk of varix bleeding was evaluated with patients stratified by their index values.

Results: The index of spleen volume-to-platelet ratio was devised from the derivation cohort. In the validation cohort, the cutoff index value for balanced sensitivity and specificity (> 3.78) resulted in the sensitivity of 69.4% and the specificity of 78.5% for detecting high-risk varix, and the cutoff index value for high sensitivity (> 1.63) detected all high-risk varices. The index stratified all patients into the low (index value ≤ 1.63; n = 118), intermediate (n = 162), and high (index value > 3.78; n = 139) risk groups with cumulative 5-year incidences of varix bleeding of 0%, 1.0%, and 12.0%, respectively (p < .001).

Conclusion: The spleen volume-to-platelet ratio obtained using deep learning-based CT analysis is useful to detect high-risk varices and to assess the risk of varix bleeding.

Key Points: • The criterion of spleen volume to platelet > 1.63 detected all high-risk varices in the validation cohort, while the absence of visible varix did not exclude all high-risk varices. • Visual varix grade ≥ 2 detected high-risk varix with a high specificity (96.5-100%). • Combining spleen volume-to-platelet ratio ≤ 1.63 and visual varix grade of 0 identified low-risk patients who had no high-risk varix and varix bleeding on 5-year follow-up.
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http://dx.doi.org/10.1007/s00330-020-07430-3DOI Listing
May 2021

CT in the prediction of margin-negative resection in pancreatic cancer following neoadjuvant treatment: a systematic review and meta-analysis.

Eur Radiol 2021 May 30;31(5):3383-3393. Epub 2020 Oct 30.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, South Korea.

Objectives: We aimed to systematically evaluate the diagnostic accuracy of CT-determined resectability following neoadjuvant treatment for predicting margin-negative resection (R0 resection) in patients with pancreatic ductal adenocarcinoma (PDAC).

Methods: Original studies with sufficient details to obtain the sensitivity and specificity of CT-determined resectability following neoadjuvant treatment, with a reference on the pathological margin status, were identified in PubMed, EMBASE, and Cochrane databases until February 24, 2020. The identified studies were divided into two groups based on the criteria of R0 resectable tumor (ordinary criterion: resectable PDAC alone; extended criterion: resectable and borderline resectable PDAC). The meta-analytic summary of the sensitivity and specificity for each criterion was estimated separately using a bivariate random-effect model. Summary results of the two criteria were compared using a joint-model bivariate meta-regression.

Results: Of 739 studies initially searched, 6 studies (6 with ordinary criterion and 5 with extended criterion) were included for analysis. The meta-analytic summary of sensitivity and specificity was 45% (95% confidence interval [CI], 19-73%; I = 88.3%) and 85% (95% CI, 65-94%; I = 60.5%) for the ordinary criterion, and 81% (95% CI, 71-87%; I = 0.0%) and 42% (95% CI, 28-57%; I = 6.2%) for the extended criterion, respectively. The diagnostic accuracy significantly differed between the two criteria (p = 0.02).

Conclusions: For determining resectability on CT, the ordinary criterion might be highly specific but insensitive for predicting R0 resection, whereas the extended criterion increased sensitivity but would decrease specificity. Further investigations using quantitative parameters may improve the identification of R0 resection.

Key Points: • CT-determined resectability of PDAC after neoadjuvant treatment using the ordinary criterion shows low sensitivity and high specificity in predicting R0 resection. • With the extended criterion, CT-determined resectability shows higher sensitivity but lower specificity than with the ordinary criterion. • CT-determined resectability with both criteria achieved suboptimal diagnostic performances, suggesting that care should be taken while selecting surgical candidates and when determining the surgical extent after neoadjuvant treatment in patients with PDAC.
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http://dx.doi.org/10.1007/s00330-020-07433-0DOI Listing
May 2021

Enhancement of Lactobionic Acid Productivity by Homologous Expression of Quinoprotein Glucose Dehydrogenase in .

J Agric Food Chem 2020 Nov 26;68(44):12336-12344. Epub 2020 Oct 26.

Bio-based Chemistry Research Center, Korea Research Institute of Chemical Technology (KRICT), 406-30, Jongga-ro, Ulsan 44429, Republic of Korea.

This is the first study on improving lactobionic acid (LBA) production capacity in by genetic engineering. First, quinoprotein glucose dehydrogenase (GDH) was identified as the lactose-oxidizing enzyme of . Of the two types of GDH genes in , membrane-bound (GDH1) and soluble (GDH2), only GDH1 showed lactose-oxidizing activity. Next, the genetic tool system for was developed based on the pDSK519 plasmid for the first time, and GDH1 gene was homologously expressed in . Recombinant expression of the GDH1 gene enhanced intracellular lactose-oxidizing activity and LBA production of in flask culture. In batch fermentation of the recombinant using a 5 L bioreactor, the LBA productivity of the recombinant was approximately 17% higher (8.70 g/(L h)) than that of the wild type (7.41 g/(L h)). The LBA productivity in this study is the highest ever reported using bacteria as production strains for LBA.
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http://dx.doi.org/10.1021/acs.jafc.0c04246DOI Listing
November 2020

Porto-sinusoidal vascular disease with portal hypertension versus liver cirrhosis: differences in imaging features on CT and hepatobiliary contrast-enhanced MRI.

Abdom Radiol (NY) 2020 Oct 23. Epub 2020 Oct 23.

Liver Cancer Center, Asan Medical Center, Seoul, Republic of Korea.

Purpose: To differentiate the computed tomography (CT) and magnetic resonance imaging (MRI) features of porto-sinusoidal vascular disease (PSVD) and liver cirrhosis (LC).

Methods: In this retrospective case-control study of patients with PSVD matched in a 1:3 ratio with LC patients according to liver function, initial diagnosis and time to final diagnosis were analyzed. Imaging features on CT and the parenchymal enhancement on hepatobiliary phase of hepatobiliary agent-enhanced MRI (HBA-MRI) were compared using a generalized linear mixed model. Focal hepatic lesions in the PSVD group were analyzed.

Results: In total, 43 PSVD patients and 129 LC patients were included. Among PSVD patients, 72.1% were initially misdiagnosed with LC. PSVD patients had a longer diagnostic delay than LC patients (32 months vs. 4 months; p < 0.001). Liver surface nodularity was less common in the PSVD group than in the LC group (16.3% vs. 89.2%, p < 0.001). Increased caudate-to-right lobe ratio, heterogeneous parenchymal enhancement, and portal vein abnormalities were more frequently noted in the PSVD group than in the LC group (all p < 0.001). The grade of portal hypertension was significantly higher in the PSVD group than in the LC group (p < 0.001), and they also had brighter parenchymal enhancement during the hepatobiliary phase of HBA-MRI (p < 0.001). In the PSVD group, 14% patients had at least one focal hepatic lesion, primarily a focal nodular hyperplasia (FNH)-like nodule.

Conclusions: Some imaging features on CT and HBA-MRI can distinguish PSVD from LC. Benign focal lesions, most commonly FNH-like nodules, can develop in PSVD.
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http://dx.doi.org/10.1007/s00261-020-02831-wDOI Listing
October 2020

Erratum: Advantages of Distal Subtotal Gastrectomy Over Total Gastrectomy in the Quality of Life of Long-Term Gastric Cancer Survivors.

J Gastric Cancer 2020 Sep 25;20(3):344. Epub 2020 Sep 25.

Department of Surgery, School of Medicine, Kyungpook National University, Daegu, Korea.

[This corrects the article on p. 176 in vol. 20, PMID: 32596001.].
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http://dx.doi.org/10.5230/jgc.2020.20.e31DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7521985PMC
September 2020

Prognostic Factors in Stage IB Gastric Cancer after Surgical Resection.

J Gastric Cancer 2020 Sep 23;20(3):328-336. Epub 2020 Sep 23.

Department of Surgery, School of Medicine, Kyungpook National University, Daegu, Korea.

Purpose: The standard treatment for stage IB gastric cancer is curative surgery alone, but some patients show poor survival with disease recurrence after curative surgery. The aim of this study was to identify prognostic factors of recurrence and long-term survival in patients with stage IB gastric cancer after surgery.

Materials And Methods: We retrospectively reviewed data from 253 patients with stage IB gastric cancer who underwent gastrectomy between 2011 and 2016 at Kyungpook National University Chilgok Hospital and analyzed the clinicopathological characteristics associated with recurrence and survival.

Results: Fourteen patients experienced recurrence with a mean follow-up of 54.1 months. Two of these patients had locoregional recurrence and 12 patients had systemic recurrence. The median interval between the operation day and the day of recurrence was 11 months (range 4-56 months). Multivariate analysis revealed that lymphatic vessel invasion (LVI) (hazard ratio [HR], 3.851; 95% confidence interval [CI], 1.264-11.732) and the elderly (age≥65) (HR, 3.850; 95% CI, 1.157-12.809) were independent risk factors for recurrence after surgery. The LVI (HR, 3.630; 95% CI, 1.105-11.923) was the independent prognostic factors for disease-specific survival (DSS). The 5-year DSS rates were 96.8% in patients who did not have LVI, and 89.3% in patients who had LVI.

Conclusions: This study shows that LVI was associated with recurrence and poor survival in patients with stage IB gastric cancer after curative gastrectomy. Patients diagnosed with LVI require careful attention for systemic recurrence during the follow-up period.
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http://dx.doi.org/10.5230/jgc.2020.20.e30DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7521982PMC
September 2020

The Liver Imaging Reporting and Data System tumor-in-vein category: a systematic review and meta-analysis.

Eur Radiol 2021 Apr 1;31(4):2497-2506. Epub 2020 Oct 1.

Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul, 06591, Republic of Korea.

Objectives: We aimed to systematically determine the etiology of the Liver Imaging Reporting and Data System (LI-RADS) tumor-in-vein category (LR-TIV) on contrast-enhanced CT or MRI and to determine the sources of heterogeneity between reported results.

Methods: Original studies reporting the etiology of LR-TIV were identified in MEDLINE and EMBASE up until July 7, 2020. The meta-analytic pooled percentages of HCC and non-HCC in LR-TIV were calculated. Subgroup analyses were performed according to the type of reference standard and the most common underlying liver disease. Meta-regression analysis was performed to explore study heterogeneity.

Results: Sixteen studies reported the etiology of a total of 150 LR-TIV, of which 98 (65%) were HCC and 52 (35%) were non-HCC. The meta-analytic pooled percentages of HCC and non-HCC in LR-TIV were 70.9% (95% confidence interval [CI], 55.7-82.5%; I = 59%) and 29.2% (95% CI, 17.5-44.4%; I = 59%), respectively. The meta-analytic pooled percentage of HCC was lower in studies using only pathology as a reference standard (67.1%; 95% CI, 49.3-81.1%), but higher in studies in which hepatitis C was the most common underlying liver disease (81.9%; 95% CI, 11.3-99.4%) than that in the total 16 studies. Study type (cohort study versus case-control study) was significantly associated with study heterogeneity (p = 0.04).

Conclusion: The most common etiology of LR-TIV was HCC. It might be important to understand the percentage of HCC and non-HCC in LR-TIV in consideration of the type of reference standard, geographic differences, and study design.

Key Points: • The most common etiology of Liver Imaging Reporting and Data System (LI-RADS) tumor-in-vein category (LR-TIV) was hepatocellular carcinoma (HCC). • The percentage of HCC in LR-TIV was relatively low in studies using only pathology as a reference standard, but high in studies in which hepatitis C was the most common underlying liver disease. • Study type was a factor significantly influencing study heterogeneity.
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http://dx.doi.org/10.1007/s00330-020-07282-xDOI Listing
April 2021

Combination Therapy with Doxorubicin-Loaded Reduced Albumin Nanoparticles and Focused Ultrasound in Mouse Breast Cancer Xenografts.

Pharmaceuticals (Basel) 2020 Sep 7;13(9). Epub 2020 Sep 7.

Department of Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-744, Korea.

Because chemotherapeutic drugs are often associated with serious side effects, the central topic in modern drug delivery is maximizing the localization of drugs at the target while minimizing non-specific drug interactions at unwanted regions. To address this issue, biocompatible nanoparticles have been developed to enhance the drug half-life while minimizing the associated toxicity. Nevertheless, relying solely on the enhanced half-life and enhanced permeability and retention (EPR) effects has been ineffective, and designing stimulus-sensitive nanoparticles to introduce the precise control of drug release has been desired. In this paper, we introduce a pH-sensitive, reduced albumin nanoparticle in combination with focused ultrasound treatment. Not only did these nanoparticles have superior therapeutic efficacy and toxicity profiles when compared to the free drugs in xenograft mouse models, but we were also able to show that the albumin nanoparticles reported in this paper were more suitable than other types of non-reduced albumin nanoparticles as vehicles for drug delivery. As such, we believe that the albumin nanoparticles presented in this paper with desirable characteristics including the induction of strong anti-tumor response, precise control, and superior safety profiles hold strong potential for preclinical and clinical anticancer therapy.
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http://dx.doi.org/10.3390/ph13090235DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7557944PMC
September 2020

Radiologic Evaluation and Structured Reporting Form for Extrahepatic Bile Duct Cancer: 2019 Consensus Recommendations from the Korean Society of Abdominal Radiology.

Korean J Radiol 2021 01 28;22(1):41-62. Epub 2020 Aug 28.

Department of Radiology, Yonsei University College of Medicine, Seoul, Korea.

Radiologic imaging is important for evaluating extrahepatic bile duct (EHD) cancers; it is used for staging tumors and evaluating the suitability of surgical resection, as surgery may be contraindicated in some cases regardless of tumor stage. However, the published general recommendations for EHD cancer and recommendations guided by the perspectives of radiologists are limited. The Korean Society of Abdominal Radiology (KSAR) study group for EHD cancer developed key questions and corresponding recommendations for the radiologic evaluation of EHD cancer and organized them into 4 sections: nomenclature and definition, imaging technique, cancer evaluation, and tumor response. A structured reporting form was also developed to allow the progressive accumulation of standardized data, which will facilitate multicenter studies and contribute more evidence for the development of recommendations.
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http://dx.doi.org/10.3348/kjr.2019.0803DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7772383PMC
January 2021

CT-determined resectability of borderline resectable and unresectable pancreatic adenocarcinoma following FOLFIRINOX therapy.

Eur Radiol 2021 Feb 26;31(2):813-823. Epub 2020 Aug 26.

Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.

Objectives: We aimed to assess the ability of CT-determined resectability, as defined by a recent version of NCCN criteria, and associated CT findings to predict margin-negative (R0) resection in patients with PDAC after neoadjuvant FOLFIRINOX chemotherapy.

Methods: Sixty-four patients (36 men and 28 women; mean age, 58.8 years) with borderline resectable or unresectable PDAC who received neoadjuvant FOLFIRINOX were evaluated retrospectively. CT findings were independently assessed by two abdominal radiologists according to NCCN criteria (version 3. 2019). Tumor resectability was classified as resectable, borderline resectable, or unresectable, and change in resectability was classified as regression, stability, or progression. The associations of R0 resection rate with CT-determined resectability and change in resectability categories were evaluated, as were the sensitivity and specificity of NCCN criteria for R0 resection. Factors associated with R0 resection were identified by logistic regression analysis.

Results: R0 resection rate did not differ significantly among the resectable, borderline resectable, or unresectable PDAC (67-73%, p = 0.95) or among PDAC with regression, stability, or progression (56-77%, p = 0.39). The sensitivity and specificity for R0 resection were 67% and 37%, respectively, for resectability (resectable/borderline vs. unresectable) and 80% and 21%, respectively, for changes in resectability (regression/stable vs. progression). Low-contrast enhancement of soft tissue contacting artery (≤ 46.4 HU) was independently associated with R0 resection (p = 0.01).

Conclusion: CT-determined resectability after neoadjuvant FOLFIRINOX chemotherapy was relatively insensitive and non-specific for predicting R0 resection. Low-contrast enhancement of soft tissue contacting artery may increase the ability of CT to predict R0 resection.

Key Points: • Margin-negative resection rate of pancreatic cancer following FOLFIRINOX therapy did not differ among each resectability (67-73%, p = 0.95) based on NCCN criteria or changes in resectability categories (56-77%, p = 0.39). • The sensitivity and specificity for margin-negative resection were 67% and 37% for resectability (resectable/borderline vs. unresectable) and 80% and 21% for changes in resectability (regression/stable vs. progression). • Low-contrast enhancement of soft tissue contacting artery (≤ 46.4 HU) was independently associated with margin-negative resection (p = 0.01).
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http://dx.doi.org/10.1007/s00330-020-07188-8DOI Listing
February 2021

Multiparametric MRI for prediction of treatment response to neoadjuvant FOLFIRINOX therapy in borderline resectable or locally advanced pancreatic cancer.

Eur Radiol 2021 Feb 19;31(2):864-874. Epub 2020 Aug 19.

Department of Surgery, University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-Ro 43-Gil, Songpa-Gu, Seoul, 05505, Republic of Korea.

Objectives: To identify multiparametric MRI biomarkers to predict the tumor response to neoadjuvant FOLFIRINOX therapy in patients with borderline resectable (BR) or locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC).

Methods: From May 2016 to March 2018, adult patients with BR or LA PDAC were prospectively enrolled in this study. They received eight cycles of FOLFIRINOX therapy and underwent multiparametric MRI twice (at baseline and after the second cycle). MRI evaluations included dynamic contrast-enhanced MRI, intravoxel incoherent motion diffusion-weighted imaging, and assessment of T2* relaxivity (R2*) and the change in T1 relaxivity (ΔR1, equilibrium phase R1 minus non-enhanced R1) of the tumors. Factors to predict the responders determined by the best overall response during FOLFIRINOX therapy and those to predict progression-free survival (PFS) and overall survival (OS) were evaluated using multivariable logistic regression and the Cox proportional hazard model.

Results: Forty-one patients (mean age, 60.3 years ± 9.3; 24 men) were included. Among the clinical and MRI factors, the baseline ΔR1 (adjusted odds ratio, 31.07; p = 0.008) was the only independent predictor for tumor response. The baseline ΔR1 was also an independent predictor for PFS (adjusted hazard ratio, 0.40; p = 0.033) along with R0 resection. The use of a cutoff ΔR1 value of ≥ 1.31 s enabled prognostic stratification (median PFS, 16.0 months vs.10.0 months; p = 0.029; median OS, 34.9 months vs. 16.6 months; p = 0 .023, respectively).

Conclusions: The baseline tumor ΔR1 value may be useful to predict tumor response and survival in patients with BR or LA PDAC receiving FOLFIRINOX neoadjuvant therapy.

Key Points: • Baseline ΔR1 was an independent predictor for tumor response (adjusted odds ratio, 31.07; p = 0.008) and progression-free survival (adjusted hazard ratio, 0.40; p = 0.033) in patients with borderline resectable or locally advanced pancreatic ductal adenocarcinoma receiving neoadjuvant FOLFIRINOX therapy. • The criterion of baseline ΔR1 value ≥ 1.31 s allowed for the prediction of favorable tumor response and survival outcome after neoadjuvant FOLFIRINOX therapy.
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http://dx.doi.org/10.1007/s00330-020-07134-8DOI Listing
February 2021

Deep Learning Algorithm for Automated Segmentation and Volume Measurement of the Liver and Spleen Using Portal Venous Phase Computed Tomography Images.

Korean J Radiol 2020 08;21(8):987-997

Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.

Objective: Measurement of the liver and spleen volumes has clinical implications. Although computed tomography (CT) volumetry is considered to be the most reliable noninvasive method for liver and spleen volume measurement, it has limited application in clinical practice due to its time-consuming segmentation process. We aimed to develop and validate a deep learning algorithm (DLA) for fully automated liver and spleen segmentation using portal venous phase CT images in various liver conditions.

Materials And Methods: A DLA for liver and spleen segmentation was trained using a development dataset of portal venous CT images from 813 patients. Performance of the DLA was evaluated in two separate test datasets: dataset-1 which included 150 CT examinations in patients with various liver conditions (i.e., healthy liver, fatty liver, chronic liver disease, cirrhosis, and post-hepatectomy) and dataset-2 which included 50 pairs of CT examinations performed at ours and other institutions. The performance of the DLA was evaluated using the dice similarity score (DSS) for segmentation and Bland-Altman 95% limits of agreement (LOA) for measurement of the volumetric indices, which was compared with that of ground truth manual segmentation.

Results: In test dataset-1, the DLA achieved a mean DSS of 0.973 and 0.974 for liver and spleen segmentation, respectively, with no significant difference in DSS across different liver conditions ( = 0.60 and 0.26 for the liver and spleen, respectively). For the measurement of volumetric indices, the Bland-Altman 95% LOA was -0.17 ± 3.07% for liver volume and -0.56 ± 3.78% for spleen volume. In test dataset-2, DLA performance using CT images obtained at outside institutions and our institution was comparable for liver (DSS, 0.982 vs. 0.983; = 0.28) and spleen (DSS, 0.969 vs. 0.968; = 0.41) segmentation.

Conclusion: The DLA enabled highly accurate segmentation and volume measurement of the liver and spleen using portal venous phase CT images of patients with various liver conditions.
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http://dx.doi.org/10.3348/kjr.2020.0237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7369202PMC
August 2020

Estimating Recurrence after Upfront Surgery in Patients with Resectable Pancreatic Ductal Adenocarcinoma by Using Pancreatic CT: Development and Validation of a Risk Score.

Radiology 2020 09 14;296(3):541-551. Epub 2020 Jul 14.

From the Department of Radiology and Research Institute of Radiology (D.W.K., S.S.L., J.H.K., H.J.K., J.H.B.), Department of Clinical Epidemiology and Biostatistics (S.O.K.), Department of Oncology (C.Y., K.P.K.), and Department of Surgery (K.B.S., S.C.K.), University of Ulsan College of Medicine, Asan Medical Center, 88 Olympic-ro 43-Gil, Songpa-Gu Seoul, Seoul 138-736, Republic of Korea.

Background No preoperative model is available for predicting postsurgical prognosis of patients with resectable pancreatic ductal adenocarcinoma (PDAC). Purpose To develop and validate a preoperative risk scoring system using clinical and CT variables to predict recurrence-free survival (RFS) after upfront surgery in patients with resectable PDAC. Materials and Methods In this retrospective study, consecutive patients with resectable PDAC underwent upfront surgery from January 2014 to December 2015 (development set) and from January 2016 to January 2017 (test set). In the development set, multivariable Cox proportional hazard modeling with bootstrapping was used to select clinical and CT variables associated with RFS and to construct a risk scoring system. The discrimination capability of the risk score was assessed by using the Harrell C-index and compared with that of pathologic American Joint Committee on Cancer tumor stage. The risk score was validated in the test set. Results A total of 395 patients were evaluated, including 262 patients (mean age ± standard deviation, 64 years ± 10; 155 men) in the development set and 133 (mean age, 64 years ± 9; 79 men) in the test set. Five independent variables predicted risk of recurrence or death: tumor size (hazard ratio [HR], 1.23; 95% confidence interval [CI]: 1.05, 1.44; = .009), hypodense tumor in the portal venous phase (HR, 1.66; 95% CI: 1.01, 2.73; = .04), tumor necrosis (HR, 2.04; 95% CI: 1.38, 3.03; < .001), peripancreatic tumor infiltration (HR, 1.50; 95% CI: 1.07, 2.11; = .02), and suspicious metastatic lymph nodes (HR, 1.94; 95% CI: 1.38, 2.72; < .001). In the test set, the risk score showed good discrimination capability (C-index of 0.68; 95% CI: 0.63, 0.74) and outperformed the pathologic tumor stage (C-index of 0.60; 95% CI: 0.55, 0.66; = .03). Patients were categorized into favorable, intermediate, and poor prognosis groups with 1-year RFS of 0.87, 0.58, and 0.26, respectively. Conclusion The presented preoperative risk score can predict recurrence-free survival after upfront surgery in patients with resectable pancreatic ductal adenocarcinoma. © RSNA, 2020 See also the editorial by Pandharipande and Anderson in this issue.
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http://dx.doi.org/10.1148/radiol.2020200281DOI Listing
September 2020

Advantages of Distal Subtotal Gastrectomy over Total Gastrectomy in the Quality of Life of Long-Term Gastric Cancer Survivors.

J Gastric Cancer 2020 Jun 4;20(2):176-189. Epub 2020 May 4.

Department of Surgery, Kyungpook National University Hospital, Daegu, Korea.

Purpose: This study evaluated differences and shifting patterns in the health-related quality of life (HRQoL) of 5-year gastric cancer survivors after either a distal subtotal gastrectomy (DSG) or total gastrectomy (TG).

Materials And Methods: We analyzed the prospectively collected HRQoL data of 528 patients who survived 5 years without recurrence using the European Organization for the Research and Treatment of Cancer (EORTC) Core Quality of Life Questionnaire and the EORTC Quality of Life Questionnaire-Stomach module according to the type of surgery. The purpose was to identify the proportion of patients with deteriorating HRQoL and to assess the clinical significance of these changes.

Results: Deteriorating HRQoL was prevalent in both groups, including a large proportion of the DSG group. Decreased overall health status and scores on several function scales were less in the DSG group, while increases on the symptom scales were higher in the TG group. For most of the scales, gaps in HRQoL during the early postoperative period did not merge within the 5 years. Scores on the diarrhea and body image scales revealed "moderate changes" in both groups.

Conclusions: During the 5-year period after surgery, the TG group suffered from inferior HRQoL compared to the DSG group. However, a large proportion of the DSG group also suffered HRQoL deterioration. In general, the TG group experienced more HRQoL decline, with diarrhea and body image being the major concerns for both groups. To improve HRQoL after gastrectomy, patients must be better informed about post-gastrectomy symptoms. These symptoms must be vigorously investigated, and medical interventions should be available parallel to nutritional support. Favorable evidence of function-preserving gastrectomy should be established and disseminated to improve the HRQoL of early gastric cancer patients.
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http://dx.doi.org/10.5230/jgc.2020.20.e17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7311217PMC
June 2020