School of Medicine, Department of Diagnostic Radiology

Job title

Assistant Professor

Education 【 display / non-display

  • 2013

    Sapporo Medical University   Graduate School of Medicine  

  • 2004

    Sapporo Medical University   School of Medicine  

Research Experience 【 display / non-display

  • 2017.12

    Sapporo Medical University  

  • 2013.10

    Sapporo Medical University   Hospital  

  • 2012.04

    Sapporo Medical University   Hospital  

  • 2011.04

    Sapporo Medical University   Hospital  


Papers 【 display / non-display

  • Repeatability analysis of ADC histogram metrics of the uterus

    Koichi Onodera, Masamitsu Hatakenaka, Naoya Yama, Maki Onodera, Tsuyoshi Saito, Thomas Christian Kwee, Taro Takahara

    Acta Radiologica   60 ( 4 ) 526 - 534  2019.04  [Refereed]  [International journal]

    Authorship:   Lead author

     View Summary

    BACKGROUND: Recently, histogram analysis based on voxel-wise apparent diffusion coefficient (ADC) value distribution has been increasingly performed. However, few studies have been reported regarding its repeatability. PURPOSE: To evaluate the repeatability of ADC histogram metrics of the uterus in clinical magnetic resonance imaging (MRI). MATERIAL AND METHODS: Thirty-three female patients who underwent pelvic MRI including diffusion-weighted imaging (DWI) were prospectively included after providing informed consent. Two sequential DWI acquisitions with identical parameters and position were obtained. Regions of interest (ROIs) for histologically confirmed uterine lesions (five cervical and three endometrial cancers, and one endometrial hyperplasia) and normal appearing tissues (21 endometrium and 33 myometrium) were assigned on the first DWI dataset and then pasted onto the second DWI dataset. ADC histogram metrics within the ROIs were calculated and repeatability was evaluated by calculating within-subject coefficient of variance (%) (wCV (%)) and Bland-Altman plot (%). RESULTS: ADC 10%, 25%, median, 75%, 90%, maximum, mean, and entropy showed high repeatability (wCV (%) < 7, 95% limit of agreement in Bland-Altman plot (%) < ±20), followed by ADC minimum (wCV (%) = 8.12, 95% limit of agreement in Bland-Altman plot (%) < ±30). However, ADC skewness and kurtosis showed very low repeatability in all evaluations. CONCLUSION: ADC histogram metrics like ADC 10%, 25%, median, 75%, 90%, maximum, mean, and entropy are robust biomarkers and could be applicable to clinical use. However, ADC skewness and kurtosis lack robustness. Radiologists should keep these characteristics and limitations in mind when interpreting quantitative DWI.

    DOI PubMed

  • Are ADC histogram metrics repeatable?

    Koichi ONODERA, Naoya YAMA, Maki ONODERA, Naomi KOYAMA, Yoshifusa KYUNA, Mitsuhiro NAKANISHI, Masamitsu HATAKENAKA

    The Sapporo Medical Journal   86 ( 1-6 ) 85 - 93  2017.12  [Refereed]

    Authorship:   Lead author