title: Bone texture analysis using CT-simulation scans to individuate risk parameters for radiation-induced insufficiency fractures.
abstract: This study deals with the role of texture analysis as a predictive factor of radiation-induced insufficiency fractures in patients undergoing pelvic radiation.
  
  
  
  This study aims to assess the texture analysis (TA) of computed tomography (CT) simulation scans as a predictive factor of insufficiency fractures (IFs) in patients with pelvic malignancies undergoing radiation therapy (RT).
  
  
  
  We performed an analysis of patients undergoing pelvic RT from January 2010 to December 2014, 24 of whom had developed pelvic bone IFs. We analyzed CT-simulation images using ImageJ macro software and selected two regions of interest (ROIs), which are L5 body and the femoral head. TA parameters included mean (m), standard deviation (SD), skewness (sk), kurtosis (k), entropy (e), and uniformity (u). The IFs patients were compared (1:2 ratio) with controlled patients who had not developed IFs and matched for sex, age, menopausal status, type of tumor, use of chemotherapy, and RT dose. A reliability test of intra- and inter-reader ROI TA reproducibility with the intra-class correlation coefficient (ICC) was performed. Univariate and multivariate analyses (logistic regression) were applied for TA parameters observed both in the IFs and the controlled groups.
  
  
  
  Inter- and intra-reader ROI TA was highly reproducible (ICC > 0.90). Significant TA parameters on paired t test included L5 m (p = 0.001), SD (p = 0.002), k (p = 0.006), e (p = 0.004), and u (p = 0.015) and femoral head m (p < 0.001) and SD (p = 0.001), whereas on logistic regression analysis, L5 e (p = 0.003) and u (p = 0.010) and femoral head m (p = 0.027), SD (p = 0.015), and sex (p = 0.044).
  
  
  
  In our experience, bone CT TA could be correlated to the risk of radiation-induced IFs. Studies on a large patient series and methodological refinements are warranted.
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy. v.nardone@hotmail.it.
authors.forename: V
authors.identifier: 0000-0002-7347-0965
authors.initials: V
authors.lastname: Nardone
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Tini
authors.affiliation: Unit of Diagnostic Imaging, University Hospital of Siena, Siena, Italy.
authors.forename: S F
authors.initials: SF
authors.lastname: Carbone
authors.affiliation: Unit of Diagnostic Imaging, University Hospital of Siena, Siena, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Grassi
authors.affiliation: Unit of Medical Physics, University Hospital of Siena, Siena, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Biondi
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Sebaste
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Carfagno
authors.affiliation: Unit of Medical Physics, University Hospital of Siena, Siena, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Vanzi
authors.affiliation: Unit of Medical Physics, University Hospital of Siena, Siena, Italy.
authors.forename: G
authors.initials: G
authors.lastname: De Otto
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Battaglia
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Rubino
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Pastina
authors.affiliation: Unit of Medical Physics, University Hospital of Siena, Siena, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Belmonte
authors.affiliation: Unit of Medical Physics, University Hospital of Siena, Siena, Italy.
authors.forename: L N
authors.initials: LN
authors.lastname: Mazzoni
authors.affiliation: Unit of Medical Physics, University Hospital of Siena, Siena, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Banci Buonamici
authors.affiliation: Unit of Diagnostic Imaging, University Hospital of Siena, Siena, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Mazzei
authors.affiliation: Unit of Radiation Oncology, University Hospital of Siena, Viale Bracci, 53100, Siena, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Pirtoli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D015775:Fractures, Stress / Q000000981:diagnostic imaging / Q000209:etiology*; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010384:Pelvic Bones / Q000293:injuries* / Q000528:radiation effects; D010386:Pelvic Neoplasms / Q000532:radiotherapy; D011237:Predictive Value of Tests; D011832:Radiation Injuries / Q000000981:diagnostic imaging / Q000209:etiology*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy / Q000009:adverse effects* / Q000379:methods; D018570:Risk Assessment / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Insufficiency fractures; Radiation therapy; Side effects; Texture analysis