Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Magnetic resonance (MR) enterography (MRE) plays a pivotal role in the management of patients with Crohn’s disease (CD) throughout the chronic disease process. With advantages such as its non-invasiveness and the ability to use several MR sequences to reflect findings of active inflammation, several MRE-based indices have been introduced to assess CD inflammatory activity. Although there is no universally accepted gold-standard score for clinical practice, the most studied scores include the Magnetic Resonance Index of Activity, simplified Magnetic Resonance Index of Activity, Nancy score, Clermont score, London score, and CD MRI Index. These MRE-based scoring systems share certain characteristics but also differ in terms of the imaging parameters included, the bowel segments evaluated, and the MR sequences required for assessment. This review article covers the key MR findings of active inflammation incorporated into these scoring systems, along with the detailed characteristics and clinical applications of MRE-based scoring systems in adult patients with CD.

Magnetic resonance (MR) enterography (MRE) plays a pivotal role in the management of patients with Crohn’s disease (CD) throughout the chronic disease process. With advantages such as its non-invasiveness and the ability to use several MR sequences to reflect findings of active inflammation, several MRE-based indices have been introduced to assess CD inflammatory activity. Although there is no universally accepted gold-standard score for clinical practice, the most studied scores include the Magnetic Resonance Index of Activity, simplified Magnetic Resonance Index of Activity, Nancy score, Clermont score, London score, and CD MRI Index. These MRE-based scoring systems share certain characteristics but also differ in terms of the imaging parameters included, the bowel segments evaluated, and the MR sequences required for assessment. This review article covers the key MR findings of active inflammation incorporated into these scoring systems, along with the detailed characteristics and clinical applications of MRE-based scoring systems in adult patients with CD.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Magnetic resonance (MR) enterography (MRE) plays a pivotal role in the management of patients with Crohn’s disease (CD) throughout the chronic disease process. With advantages such as its non-invasiveness and the ability to use several MR sequences to reflect findings of active inflammation, several MRE-based indices have been introduced to assess CD inflammatory activity. Although there is no universally accepted gold-standard score for clinical practice, the most studied scores include the Magnetic Resonance Index of Activity, simplified Magnetic Resonance Index of Activity, Nancy score, Clermont score, London score, and CD MRI Index. These MRE-based scoring systems share certain characteristics but also differ in terms of the imaging parameters included, the bowel segments evaluated, and the MR sequences required for assessment. This review article covers the key MR findings of active inflammation incorporated into these scoring systems, along with the detailed characteristics and clinical applications of MRE-based scoring systems in adult patients with CD.

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area.Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version.Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Purpose: Acquisition time reduction in diffusion-weighted imaging (DWI) can be achieved by the combining multiband and variable-rate selective excitation (MB-VERSE). This study attempted to evaluate and compare the image quality (IQ) and focal lesion detectability of the respiratory-triggered MB-VERSE DWI with conventional DWI for liver magnetic resonance imaging. Materials and Methods: The acquisition time, IQ, and focal lesion detectability of MBVERSE DWI and conventional DWI were compared in 144 patients. Qualitative (overall IQ, IQ at the liver dome, sharpness of the liver margin, and degree of artifacts) and quantitative (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], and apparent diffusion co efficient) IQ parameters were compared with the Wilcoxon signed-rank test. The diagnostic accuracy for focal lesion detectability was estimated with the mean figure of merit (FOM) from the area under the jackknife alternative free-response receiver operating characteristic curve. Results: The MB-VERSE DWI exhibited significantly shorter scan time (153.1 ± 34.5 s vs.225.1 ± 33.0 s, p < 0.001), poorer qualitative IQ (3.4 vs. 3.9, p < 0.001), lower SNR (34.4 vs. 50.0, p < 0.001), but comparable CNR (57.5 ± 49.0 vs. 78.9 ± 75.6, p = 0.070) compared to those of the conventional DWI. The MB-VERSE DWI exhibited similar per-lesion sensitivities (85.1%–88.1% vs. 88.1%–92.5%) and specificities (99.7%–99.8% vs. 99.5%–99.8%) of focal lesion detectability (p > 0.050) and similar diagnostic accuracy (FOM, 0.958 vs.0.957, p = 0.583) compared to those of the conventional DWI. Conclusion MB-VERSE DWI exhibited a significantly shorter acquisition time than conventional DWI, with compromised overall IQ and lower SNR but preserved CNR and focal liver lesion detectability. MB-VERSE DWI may be a useful alternative for patients requiring a short acquisition time.

Objective: To measure inter-reader agreement and identify associated factors in interpreting complete response (CR) on magnetic resonance imaging (MRI) following chemoradiotherapy (CRT) for rectal cancer. Materials and Methods: This retrospective study involved 10 readers from seven hospitals with experience of 80–10210 cases, and 149 patients who underwent surgery after CRT for rectal cancer. Using MRI-based tumor regression grading (mrTRG) and methods employed in daily practice, the readers independently assessed mrTRG, CR on T2-weighted images (T2WI) denoted as mrCR T2W, and CR on all images including diffusion-weighted images (DWI) denoted as mrCRoverall. The readers described their interpretation patterns and how they utilized DWI. Inter-reader agreement was measured using multi-rater kappa, and associated factors were analyzed using multivariable regression. Correlation between sensitivity and specificity of each reader was analyzed using Spearman coefficient. Results: The mrCR T2W and mrCRoverall rates varied widely among the readers, ranging 18.8%–40.3% and 18.1%–34.9%, respectively. Nine readers used DWI as a supplement sequence, which modified interpretations on T2WI in 2.7% of cases (36/1341 [149 patients x 9 readers]) and mostly (33/36) changed mrCR T2W to non-mrCRoverall. The kappa values for mrTRG, mrCR T2W, and mrCRoverall were 0.56 (95% confidence interval: 0.49, 0.62), 0.55 (0.52, 0.57), and 0.54 (0.51, 0.57), respectively.No use of rectal gel, larger initial tumor size, and higher initial cT stage exhibited significant association with a higher interreader agreement for assessing mrCRoverall (P ≤ 0.042). Strong negative correlations were observed between the sensitivity and specificity of individual readers (coefficient, -0.718 to -0.963; P ≤ 0.019). Conclusion Inter-reader agreement was moderate for assessing CR on post-CRT MRI. Readers’ varying standards on MRI interpretation (i.e., threshold effect), along with the use of rectal gel, initial tumor size, and initial cT stage, were significant factors associated with inter-reader agreement.

While ultrasound (US) is considered an important tool for hepatocellular carcinoma (HCC) surveillance, it has limited sensitivity for detecting early-stage HCC. Abbreviated MRI (AMRI) has recently gained popularity owing to better sensitivity in its detection of early-stage HCC than US, while also minimizing the time and cost in comparison to complete contrastenhanced MRI, as AMRI includes only a few essential sequences tailored for detecting HCC. Currently, three AMRI protocols exist, namely gadoxetic acid-enhanced hepatobiliary-phase AMRI, dynamic contrast-enhanced AMRI, and non-enhanced AMRI. In this study, we discussed the rationale and technical details of AMRI techniques for achieving optimal surveillance performance. The strengths, weaknesses, and current issues of each AMRI protocol were also elucidated. Moreover, we scrutinized previously performed AMRI studies regarding clinical and technical factors. Reporting and recall strategies were discussed while considering the differences in AMRI protocols. A risk-stratified approach for the target population should be taken to maximize the benefits of AMRI and the cost-effectiveness should be considered. In the era of multiple HCC surveillance tools, patients need to be fully informed about their choices for better adherence to a surveillance program.