title: Magnitude and influencing factors of respiration-induced liver motion during abdominal compression in patients with intrahepatic tumors.
abstract: OBJECTIVE
  The purpose of this study was to use 4-dimensional-computed tomography (4D-CT) to evaluate respiration-induced liver motion magnitude and influencing factors in patients with intrahepatic tumors undergoing abdominal compression.
  
  
  METHODS
  From January 2012 to April 2016, 99 patients with intrahepatic tumors were included in this study. They all underwent 4D-CT to assess respiratory liver motion. This was performed during abdominal compression in 53 patients and during free-breathing (no abdominal compression) in 46 patients. We defined abdominal compression as being effective in managing the breath amplitude if respiration-induced liver motion in the cranial-caudal (CC) direction during compression was ≤5 mm and as being ineffective if >5 mm of motion was observed. Gender, age, body mass index (BMI), transarterial chemoembolization history, liver resection history, tumor area, tumor number, and tumor size (diameter) were determined. Multivariate logistic regression analysis was used to analyze influencing factors associated with a breath amplitude ≤5 mm in the CC direction.
  
  
  RESULTS
  The mean respiration-induced liver motion during abdominal compression in the left-right (LR), CC, anterior-posterior (AP), and 3-dimensional vector directions was 2.9 ± 1.2 mm, 5.3 ± 2.2 mm, 2.3 ± 1.1 mm and 6.7 ± 2.1 mm, respectively. Univariate analysis indicated that gender and BMI significantly affected abdominal compression effectiveness (both p < 0.05). Multivariate analysis confirmed these two factors as significant predictors of effective abdominal compression: gender (p = 0.030) and BMI (p = 0.006). There was a strong correlation between gender and compression effectiveness (odds ratio [OR] = 7.450) and an even stronger correlation between BMI and compression effectiveness (OR = 10.842).
  
  
  CONCLUSIONS
  The magnitude of respiration-induced liver motion of patients with intrahepatic carcinoma undergoing abdominal compression is affected by gender and BMI, with abdominal compression being less effective in men and overweight patients.
authors.affiliation: Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180, Feng Lin Road, Shanghai, 200032, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180, Feng Lin Road, Shanghai, 200032, China.
authors.forename: Yong-Kang
authors.initials: YK
authors.lastname: Zhou
authors.affiliation: Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180, Feng Lin Road, Shanghai, 200032, China.
authors.forename: Yi-Xing
authors.initials: YX
authors.lastname: Chen
authors.affiliation: Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180, Feng Lin Road, Shanghai, 200032, China. zeng.zhaochong@zs-hospital.sh.cn.
authors.forename: Zhao-Chong
authors.initials: ZC
authors.lastname: Zeng
mesh_terms: D000005:Abdomen / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D009038:Motion; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D056888:Patient Positioning / Q000295:instrumentation* / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods; D012119:Respiration; D055815:Young Adult
keywords: Abdominal compression; Body mass index (BMI); Four-dimensional computed tomography; Respiratory liver motion