Mizutani, Mari

写真a

Affiliation

School of Medicine, Cancer Center ( Shinanomachi )

Position

Instructor
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Papers 【 Display / hide 】

  • Diagnostic Performance and Reproducibility of Chromoendoscopic Classification (FOCUS Classification: Flat-Type Dysplasia Optical Assessment by Chromoendoscopy in Ulcerative ColitiS) for Flat-Type Dysplasia in Ulcerative Colitis-Associated Neoplasia

    Takabayashi K., Murata S., Sasaki M., Miyazaki K., Masunaga T., Kirita K., Mizutani M., Yoshimatsu Y., Takatori Y., Akimoto T., Kiyohara H., Sugimoto S., Kawasaki S., Mikami Y., Matsuura N., Nakayama A., Sujino T., Ito Y., Yamanoi K., Sekine S., Iwao Y., Yahagi N., Kanai T., Kato M.

    Digestive Endoscopy Official Journal of the Japan Gastroenterological Endoscopy Society 38 ( 9 )  2026.09

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    OBJECTIVES: Ulcerative colitis-associated neoplasia (UCAN) often presents as flat-type dysplasia that is difficult to characterize endoscopically. We developed a FOCUS (Flat-type dysplasia Optical assessment by Chromoendoscopy in Ulcerative colitiS) classification and evaluated its diagnostic performance and reproducibility. METHODS: This single-center retrospective study included 33 UCAN lesions from 26 patients. Prospectively recorded FOCUS classifications at 230 biopsy sites were compared with histopathology. Chromoendoscopic patterns were categorized as Type I ("suggestive of non-dysplasia,"), Type II ("suggestive of dysplasia with low confidence"), or Type III ("suggestive of dysplasia with high confidence"). Diagnostic performance was assessed using two prespecified thresholds: Types II/III versus Type I and Type III versus Types I/II. Eight endoscopists independently classified all images; interobserver and intraobserver agreement were assessed using Fleiss' and Cohen's κ, respectively. RESULTS: The dysplasia-bearing rate increased stepwise from Type I to Type III (Type I 15.5%, Type II 58.3%, Type III 81.8%). Using the primary threshold, sensitivity was 82.0%, and specificity 75.4% (positive likelihood ratio 3.33; negative likelihood ratio 0.24). Interobserver agreement for the three-category classification was moderate to substantial (Fleiss' κ 0.629; 95% CI 0.545-0.712), and median intraobserver agreement was substantial (Cohen's κ 0.738). CONCLUSIONS: The FOCUS classification provides clinically meaningful risk stratification for flat-type dysplasia in a high-risk UCAN cohort, with acceptable interobserver and intraobserver reproducibility.

  • Clinical Outcomes of Underwater Endoscopic Submucosal Dissection for Duodenal Tumors: A Systematic Review and Meta-Analysis

    Kirita K., Akimoto T., Sato Y., Sasaki M., Ishizawa M., Owada M., Katsumi A., Kubo Y., Sugawara M., Mizobe R., Murata S., Imura Y., Sakurai H., Tojo A., Miyazaki K., Masunaga T., Mizutani M., Takatori Y., Kawasaki S., Matsuura N., Nakayama A., Sujino T., Takabayashi K., Yahagi N., Kato M.

    Digestive Endoscopy 38 ( 8 )  2026.08

    ISSN  09155635

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    Background and Study Aim: Underwater endoscopic submucosal dissection (U-ESD) has recently been introduced as a technique that may improve visualization and submucosal layer expansion. However, the clinical outcomes of U-ESD for duodenal tumors have not been systematically evaluated. This study aimed to assess the efficacy and safety of U-ESD for duodenal tumors through a systematic review and meta-analysis. Patients and Methods: A comprehensive literature search was conducted using PubMed, Scopus, and the Cochrane Library from database inception to December 12, 2025. Studies evaluating U-ESD for duodenal tumors were included. Primary outcomes included en bloc resection, R0 resection, procedure time, adverse events, and complete mucosal defect closure. Pooled estimates were calculated using a random-effects model. Results: Four retrospective studies comprising 298 lesions treated with U-ESD were included. The pooled procedure time was 59 min (95% CI, 48–70 min; I<sup>2</sup> = 72%). The pooled en bloc resection rate was 99% (95% CI, 97%–100%; I<sup>2</sup> = 0%), and the pooled R0 resection rate was 89% (95% CI, 81%–93%; I<sup>2</sup> = 54%). The pooled intraoperative perforation rate was 5% (95% CI, 1%–23%; I<sup>2</sup> = 88%). The pooled delayed perforation and delayed bleeding rates were 1% (95% CI, 0%–3%; I<sup>2</sup> = 0%) and 2% (95% CI, 1%–5%; I<sup>2</sup> = 0%), respectively. Conclusion: Current evidence suggests that U-ESD is a feasible treatment option for duodenal tumors and is associated with favorable clinical outcomes. However, the available evidence remains limited, and potential biases and concerns regarding generalizability warrant cautious interpretation of these findings.

  • Predictors of local recurrence and piecemeal resection in duodenal underwater endoscopic mucosal resection

    Minezaki D., Akimoto T., Sasaki M., Murata S., Imura Y., Tojo A., Sakurai H., Iwata K., Miyazaki K., Masunaga T., Mizutani M., Kirita K., Tsutsumi K., Nishikawa M., Takatori Y., Kawasaki S., Matsuura N., Tomida H., Nakayama A., Sujino T., Takabayashi K., Mizukami K., Kato M., Yahagi N.

    Igie 5 ( 2 ) 151 - 160 2026.06

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    Background and Aims Underwater endoscopic mucosal resection (UEMR) has been widely adopted for the treatment of superficial nonampullary duodenal epithelial tumors (SNADETs). The aim of this study was to identify predictors of local recurrence and piecemeal resection in UEMR for SNADETs. Methods This is a retrospective single-center study. Patients who underwent UEMR for SNADETs between November 2017 and October 2024 were included. We documented clinicopathologic characteristics of patients and lesions, noted procedure-related outcomes, and evaluated local recurrence. Kaplan-Meier analysis was used to assess recurrence-free survival, and logistic regression analysis was performed to identify the predictors of piecemeal resection. Results Among the 367 patients, the rate of piecemeal resection was 11.2%, and the rate of en bloc resection with histologically tumor-free horizontal and vertical margins (R0) was 65.1%. No intraoperative perforations occurred; intraoperative bleeding was observed in 1.9%. Kaplan-Meier analysis of recurrence-free survival showed significantly poorer outcomes in the piecemeal resection group than the en bloc resection group (log-rank test, P < .001; Wilcoxon test, P < .001). According to multivariate logistic regression analysis, each 1-mm increase in lesion size (odds ratio [OR], 1.20; 95% confidence interval [CI], 1.11-1.31; P < .001) and a flat macroscopic type (OR, 12.49; 95% CI, 1.45-107.98; P = .02) were significant independent predictors of piecemeal resection. Conclusions Piecemeal resection was a risk factor for local recurrence in UEMR for SNADETs. In addition, each 1-mm increase in lesion size and a flat macroscopic type were significant independent predictors of piecemeal resection.

  • Real-World Evaluation of Remimazolam for Sedation During Gastrointestinal Endoscopy: Efficacy, Safety, and Risk Factors

    Sakurai H., Miyazaki K., Nakayama A., Sasaki M., Oowada M., Sugawara M., Kubo Y., Mizobe R., Katsumi A., Ishizawa M., Imura Y., Murata S., Minezaki D., Iwata K., Tojo A., Masunaga T., Kirita K., Mizutani M., Nishikawa M., Takatori Y., Akimoto T., Kawasaki S., Matsuura N., Tomida H., Sujino T., Takabayashi K., Takanori K., Yahagi N., Kato M.

    Jgh Open 10 ( 2 )  2026.02

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    Background and Aim: Remimazolam is a benzodiazepine receptor agonist intravenous anesthetic. This study aimed to evaluate the efficacy and safety of remimazolam for sedation during gastrointestinal endoscopy using real-world clinical data. Methods: This retrospective observational study included 352 patients who underwent esophagogastroduodenoscopy or colonoscopy sedated with remimazolam between January and February 2024 at our institution. Outcomes included the incidence of awakening during procedures, the sedation completion rate, and the incidence and severity of adverse events. Multivariate logistic regression analyses identified factors associated with hypoxia and hypotension. Results: Median patient age was 67 years (IQR: 58–74), and 62.2% were male. Median initial and additional doses were 3 (IQR: 2–3 mg) and 1 mg (IQR: 0–2 mg). Awakening occurred in 19.0% of patients. The sedation completion rate was 100%. Adverse events included hypotension (7.8%), hypoxia (13.1%), and bradycardia (4.0%), and no serious adverse events were observed. The only risk factor for hypoxia was advanced age (Odds ratio 1.04, 95% confidence interval: 1.01–1.08, p = 0.03), and the dose of remimazolam itself was not an independent risk factor for either hypoxia or hypotension. Conclusions: Remimazolam usage for gastrointestinal endoscopic sedation showed a favorable safety profile. Advanced age was associated with an increased risk of hypoxia, suggesting that careful monitoring and individualized sedation protocols are especially necessary for elderly patients. On the other hand, there are still issues regarding the duration of sedation. During long procedures, it is necessary to frequently check the depth of sedation to avoid undersedation.

  • Prospective Validation of Magnified Endoscopic Examination with Image-Enhanced Endoscopy as an Optical Biopsy for Differentiating Superficial Duodenal Epithelial Tumor and Non-Neoplastic Lesion in Duodenum

    Nakayama A., Kubosawa Y., Minezaki D., Morioka K., Iwata K., Miyazaki K., Masunaga T., Hayashi Y., Mizutani M., Akimoto T., Takatori Y., Matsuura N., Sujino T., Takabayashi K., Yahagi N., Kato M.

    Acta Haematologica    1 - 11 2026

    ISSN  00015792

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    Abstract – Introduction: Superficial duodenal epithelial tumors (SDETs) and non-neoplastic lesions (NNLs) often appear similar on conventional endoscopy, complicating real-time differentiation and leading to frequent biopsies. However, duodenal biopsy is invasive and may hinder subsequent endoscopic resection. We previously developed a diagnostic algorithm using magnified endoscopic examination with image-enhanced endoscopy (IEE-ME) to distinguish SDETs from NNLs. This study aimed to prospectively validate the diagnostic performance of this algorithm in clinical practice. Methods: In this single-center prospective observational study, we evaluated an IEE-ME-based diagnostic algorithm for esophagogastroduodenoscopy. Lesions were classified according to predefined criteria, including superficial structure, white opaque substance, demarcation line, and enlarged marginal epithelium. Endoscopic diagnoses were made immediately by 11 endoscopists with varied experience, who were blinded to the final histopathological diagnoses. The diagnostic performance was assessed using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy. Results: Among 241 lesions analyzed, 84 and 157 were histologically diagnosed as SDETs and NNLs, respectively. The diagnostic algorithm demonstrated excellent performance, with a sensitivity of 97.6% (95% confidence interval [CI]: 91.7–99.7%), specificity of 95.5% (95% CI: 91.0–98.2%), PPV of 92.1% (95% CI: 85.0–96.0%), NPV of 98.7% (95% CI: 95.0–99.7%), and overall accuracy of 96.3% (95% CI: 93.0–98.3%). Conclusion: This prospective validation showed that IEE-ME, applied through a structured algorithm, enables highly accurate and noninvasive differentiation between SDETs and NNLs. Given its excellent NPV and accuracy, this approach may serve as an optical biopsy method that reduces the need for conventional biopsies in clinical practice.This prospective observational study evaluated the diagnostic performance and clinical applicability of magnified endoscopic examination with image-enhanced endoscopy (IEE-ME) as an optical biopsy for differentiating superficial duodenal epithelial tumors (SDETs) from non-neoplastic lesions (NNLs) in the duodenum. Accurate discrimination of these lesions is essential for appropriate management; however, endoscopic diagnosis remains challenging. Duodenal biopsy carries potential risks such as bleeding and perforation. Therefore, a reliable and noninvasive diagnostic strategy is highly desirable. In this study, patients with some duodenal lesions were prospectively enrolled, and a previously proposed IEE-ME-based diagnostic algorithm was validated under real-world clinical conditions. Endoscopic diagnoses were performed in real time during routine examinations by endoscopists with varying levels of experience, enhancing the generalizability of the findings. Histopathological assessment, conducted in a blinded manner, served as the reference standard for diagnosis. The IEE-ME-based algorithm demonstrated excellent diagnostic performance, achieving a sensitivity of 97.6%, specificity of 95.5%, positive predictive value of 92.1%, negative predictive value of 98.7%, and accuracy of 96.3%. These results indicate that IEE-ME enables highly accurate differentiation between SDETs and NNLs without the need for routine biopsy. By employing a prospective design, incorporating real-time endoscopic evaluation, and including endoscopists with diverse experience levels, this study provides robust evidence supporting the clinical utility of IEE-ME. Our findings suggest that IEE-ME represents a practical and effective optical biopsy technique, with the potential to reduce unnecessary biopsies, minimize procedure-related risks, and optimize the management of superficial duodenal lesions in daily endoscopic practice.

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