Publications by authors named "Seungchul Han"

Purpose: This study aimed to evaluate whether an immediate short waiting period after radiofrequency ablation (RFA) can improve the accuracy of ultrasound (US)-based assessment of the ablation zone in patients with hepatocellular carcinoma (HCC).

Methods: A prospective cohort study was conducted involving 41 patients who underwent USguided RFA for HCC. Tumor margin conspicuity, electrode tip visibility, and operator confidence in assessing the ablative margin were recorded immediately following electrode deactivation and at 1-minute intervals for 5 minutes.

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Purpose: To compare the diagnostic performance of non-contrast abbreviated liver MRI (abMRI) and standard MRI (sMRI) with gadoxetic acid enhancement in the detection of liver metastasis during the initial workup for patients with breast cancer.

Methods: Of 7621 patients diagnosed with breast cancer who underwent abdominopelvic CT for their initial staging, 222 underwent sMRI between January 2016 and June 2019 to evaluate and/or characterize CT-indeterminate liver lesions. The abMRI protocol included diffusion-weighted images, apparent diffusion coefficient maps, and T2-weighted fat-suppression images, while the reference standard was histopathology or composite imaging follow-up.

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Objectives: To propose a simplified diagnostic approach for mucinous cystic neoplasm (MCN) of the liver and compare its diagnostic performance with the European Association for the Study of the Liver (EASL) criteria.

Methods: We conducted a retrospective cohort study of 124 patients with pathologically confirmed lesions (13 MCNs, 111 hepatic cysts) who underwent CT/MRI between January 2016 and January 2023. Two major features (thick septation, nodularity) and five minor features (upstream biliary dilatation, thin septations, internal hemorrhage, perfusion change, < 3 coexistent hepatic cysts) of the EASL criteria were evaluated.

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Incidentally detected gallbladder polyps (GBPs) and gallbladder wall thickening (GBWT) are frequently encountered in clinical practice. However, characterizing GBPs and GBWT in asymptomatic patients can be challenging and may result in overtreatment, including unnecessary follow-ups or surgeries. The Korean Society of Abdominal Radiology (KSAR) Clinical Practice Guideline Committee has developed expert recommendations that focus on standardized imaging interpretation and follow-up strategies for both GBPs and GBWT, with support from the Korean Society of Radiology and KSAR.

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Background: Radiofrequency ablation (RFA) of subphrenic hepatocellular carcinomas (HCCs) using ultrasound (US) guidance presents a challenge.

Purpose: To evaluate local tumor progression (LTP) and overall survival (OS) after RFA of right posterior subphrenic HCCs, and to identify the risk factors for LTP and OS after RFA.

Material And Methods: We screened patients who underwent US-guided RFA for a single HCC <3 cm in the right posterior subphrenic area.

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Article Synopsis
  • - The study evaluated the effectiveness of virtual monoenergetic images (at 50 keV) from dual-layer spectral CT (DLSCT) in detecting colorectal liver metastasis (CRLM) compared to standard iDose images, using a sample of 173 patients.
  • - Findings revealed that 50 keV images had higher rates of lesion detection (45% vs. 40%) and better visibility of CRLMs, but lower specificity for diagnosis (94.5% vs. 96%) and more indeterminate lesions.
  • - In conclusion, while 50 keV images showed superior detection and visibility of CRLM, they did not significantly enhance diagnostic accuracy, indicating a trade-off between detection and specificity. *
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Local ablation for hepatocellular carcinoma, a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements.

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Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements.

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Local ablation for hepatocellular carcinoma (HCC), a non-surgical option that directly targets and destroys tumor cells, has advanced significantly since the 1990s. Therapies with different energy sources, such as radiofrequency ablation, microwave ablation, and cryoablation, employ different mechanisms to induce tumor necrosis. The precision, safety, and effectiveness of these therapies have increased with advances in guiding technologies and device improvements.

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Our objective was to develop and evaluate the clinical feasibility of deep-learning-based synthetic contrast-enhanced computed tomography (DL-SynCCT) in patients designated for nonenhanced CT (NECT). We proposed a weakly supervised learning with the utilization of virtual non-contrast CT (VNC) for the development of DL-SynCCT. Training and internal validations were performed with 2202 pairs of retrospectively collected contrast-enhanced CT (CECT) images with the corresponding VNC images acquired from dual-energy CT.

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Local ablation therapy, encompassing radiofrequency ablation (RFA), microwave ablation, and cryoablation, has emerged as a crucial strategy for managing small hepatocellular carcinomas (HCCs), complementing liver resection and transplantation. This review delves into the clinical significance of tumor size, location, and biology in guiding treatment decisions for HCCs undergoing local ablation therapy, with a focus on tumors smaller than 3 cm. Tumor size significantly influences treatment outcomes, with larger tumors associated with poorer local tumor control due to challenges in creating sufficient ablative margins and the likelihood of microvascular invasion and peritumoral satellite nodules.

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Objective: We analyzed the incidence and mortality rate of gastrointestinal (GI) tract perforation after radiofrequency ablation (RFA) for hepatic tumors and assess its risk factors.

Methods: This retrospective cohort study included 4799 patients with malignant tumors who underwent RFA (n = 7206). Sixty-nine cases of thermal injury to the GI tract were identified via a search of the electronic medical record system using index terms and divided into two groups according to the thermal injury with (n = 8) or without (n = 61) GI tract perforation based on follow-up CT reports.

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Background/aim: This study aimed to compare the oncological outcomes of proton beam radiotherapy (PBT) with those of radiofrequency ablation (RFA) for newly diagnosed hepatocellular carcinoma (HCC).

Patients And Methods: This study included 323 patients who underwent PBT (n=40) or RFA (n=283) as a curative treatment for previously untreated HCC between October 2016 and June 2021. The primary endpoints were local progression and toxicity.

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Article Synopsis
  • Magnetic resonance elastography (MRE) is an effective noninvasive method for diagnosing liver fibrosis and predicting intrahepatic recurrence in patients with hepatocellular carcinoma (HCC) after surgery.
  • A study of 80 patients showed that a liver stiffness (LS) measurement of 4.35 kPa or higher indicated a higher likelihood of recurrence, with 16.3% of patients experiencing it over a median follow-up of 32 months.
  • The research found that MRE-recurrence and microvascular invasion were significant independent factors affecting recurrence-free survival rates, highlighting the potential of MRE in preoperative assessments.
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We aimed to evaluate the added value of positive intraluminal contrast computed tomography (CT) over fluoroscopy in detecting anastomotic leakage after gastrointestinal (GI) surgery. A total of 141 GI surgery patients who underwent fluoroscopic examination and CT were included. Two radiologists reviewed the fluoroscopic images with and without CT to determine anastomotic leakage on a 5-point confidence scale and graded the leakage on a 4-point grading system.

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Background: Percutaneous radiofrequency ablation (RFA) is pivotal for treating small malignant liver tumors, but tumors often remain inconspicuous on B-mode ultrasound (US). This study evaluates the potential of CEUS-CT/MRI fusion imaging (FI) to improve tumor visibility and the associated RFA outcomes for small (≤ 3 cm) malignant liver tumors that were inconspicuous on US.

Methods: Between January 2019 and April 2021, a prospective study enrolled 248 patients with liver malignancies (≤ 3 cm) that were poorly visible on B-mode US.

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Objectives: To assess whether the Liver Imaging Reporting and Data System (LI-RADS) category is associated with the treatment outcomes of small single hepatocellular carcinoma (HCC) after surgical resection (SR) and radiofrequency ablation (RFA).

Methods: This retrospective study included 357 patients who underwent SR (n = 209) or RFA (n = 148) for a single HCC of ≤ 3 cm between 2014 and 2016. LI-RADS categories were assigned.

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Objective: To investigate the association among the electrode placement method, electrode type, and local tumor progression (LTP) following percutaneous radiofrequency ablation (RFA) for small hepatocellular carcinomas (HCCs) and to assess the risk factors for LTP.

Materials And Methods: In this retrospective study, we enrolled 211 patients, including 150 males and 61 females, who had undergone ultrasound-guided RFA for a single HCC < 3 cm. Patients were divided into four combination groups of the electrode type and placement method: 1) tumor-puncturing with an internally cooled tip (ICT), 2) tumor-puncturing with an internally cooled wet tip (ICWT), 3) no-touch with ICT, and 4) no-touch with ICWT.

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Radiofrequency ablation (RFA) has been widely used to manage hepatocellular carcinomas (HCCs) equal to or smaller than 3 cm. No-touch RFA has gained attention and has recently been implemented in local ablation therapy for HCCs, despite its technical complexity, as it provides improved local tumor control compared to conventional tumor-puncturing RFA. This article presents the practice guidelines for performing no-touch RFA for HCCs, which have been endorsed by the Korean Society of Image-Guided Tumor Ablation (KSITA).

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Objective: The aim of the work described here was to evaluate the diagnostic performance of perfluorobutane (PFB)-enhanced ultrasound in differentiating hepatocellular carcinoma (HCC) from non-HCC malignancies and other benign lesions using different acquisition methods.

Methods: This prospective study included 69 patients with solid liver lesions larger than 1 cm who were scheduled for biopsy or radiofrequency ablation between September 2020 and March 2021. Lesion diagnosis was designated by three blinded radiologists after reviewing three different sets of acquired images selected according to the following presumed acquisition methods: (i) method A, acquisition up to 5 min after contrast injection; (ii) method B, acquisition up to 1 min after contrast injection with additional Kupffer phase; and (iii) method C, acquisition up to 5 min after contrast injection with additional Kupffer phase.

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Article Synopsis
  • This study aimed to evaluate the effectiveness of a deep-learning contrast-boosting algorithm on low-dose CT scans in patients at high risk for liver cancer (HCC), focusing on image quality and how well lesions are displayed.* -
  • Participants underwent CT scans using two different protocols: a standard-dose (SD) and a double-low-dose (DLD) protocol, with analyses revealing that the DLD protocol used less radiation and contrast agent while still achieving better contrast-to-noise ratios (CNR) for vessels.* -
  • Ultimately, the deep-learning algorithm improved image quality without reducing the ability to detect liver lesions, indicating that it could be a safer option for high-risk patients needing imaging.*
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Objective: Low monoenergetic images obtained using noise-reduction techniques may reduce CT contrast media requirements. We aimed to investigate the effectiveness of low-contrast-dose CT using dual-energy CT and deep learning-based denoising (DLD) techniques in patients at high risk of hepatocellular carcinoma (HCC).

Methods: We performed a prospective, randomized controlled noninferiority trial at a tertiary hospital between June 2019 and August 2020 (NCT04027556).

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Purpose: To compare the image quality and performance of half-Fourier acquisition single-shot turbo spin echo (HASTE) sequences, using compressed sensing (HASTE-CS) and deep-learning based reconstruction (HASTE-DL) in detecting focal liver lesions (FLLs), to those of T2-weighted image using BLADE sequence (T2WI) in patients at risk of developing hepatocellular carcinoma (HCC).

Materials And Methods: This retrospective study included patients at risk of developing HCC who underwent liver MRI including HASTE-DL, HASTE-CS, T2WI and DWI between January and June 2020. Three radiologists independently reviewed the image quality along with FLL detection in the three T2-based sequences and DWI.

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Objectives: The aim of this study was to compare compressed sensing (CS) and view sharing (VS) techniques for single breath-hold multiarterial phase imaging with respect to image quality and focal liver observation detectability during gadoxetic acid-enhanced magnetic resonance imaging in patients at high risk for hepatocellular carcinoma (HCC).

Materials And Methods: A total of 385 patients who underwent gadoxetic acid-enhanced magnetic resonance imaging, including triple arterial phases using either CS (n = 224) or VS (n = 161) techniques, were retrospectively included. Among them, 117 patients had 171 focal liver observations (median diameter, 1.

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Objectives: To compare the overall image quality and detectability of significant (malignant and pre-malignant) liver lesions of low-dose liver CT (LDCT, 33.3% dose) using deep learning denoising (DLD) to standard-dose CT (SDCT, 100% dose) using model-based iterative reconstruction (MBIR).

Methods: In this retrospective study, CT images of 80 patients with hepatic focal lesions were included.

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