title: Microsimulation model of CT versus MRI surveillance of Bosniak IIF renal cystic lesions: should effects of radiation exposure affect selection of imaging strategy?
abstract: OBJECTIVE
  The objective of this study was to quantify the effects of radiation-induced cancer risks in patients with Bosniak category IIF lesions undergoing CT versus MRI surveillance.
  
  
  METHODS
  We developed a Markov-Monte Carlo model to determine life expectancy losses attributable to radiation-induced cancers in hypothetical patients undergoing CT versus MRI surveillance of Bosniak IIF lesions. Our model tracked hypothetical patients as they underwent imaging surveillance for up to 5 years, accounting for potential lesion progression and treatment. Estimates of radiation-induced cancer mortality were generated using a published organ-specific radiation-risk model based on Biological Effects of Ionizing Radiation VII methods. The model also incorporated surgical mortality and renal cancer-specific mortality. Our primary outcome was life expectancy loss attributable to radiation-induced cancers. A sensitivity analysis was performed to assess the stability of the results with variability in key parameters.
  
  
  RESULTS
  The mean number of examinations per patient was 6.3. In the base case, assuming 13 mSv per multiphase CT examination, 64-year-old men experienced an average life expectancy decrease of 5.5 days attributable to radiation-induced cancers from CT; 64-year-old women experienced a corresponding life expectancy loss of 6.9 days. The results were most sensitive to patient age: Life expectancy loss attributable to radiation-induced cancers increased to 21.6 days in 20-year-old women and 20.0 days in 20-year-old men. Varied assumptions of each modality's (CT vs MRI) depiction of lesion complexity also impacted life expectancy losses.
  
  
  CONCLUSIONS
  Microsimulation modeling shows that radiation-induced cancer risks from CT surveillance for Bosniak IIF lesions minimally affect life expectancy. However, as progressively younger patients are considered, increasing radiation risks merit stronger consideration of MRI surveillance.
authors.affiliation: 1 Department of Radiology, NYU Langone Medical Center, 550 First Ave, New York, NY 10016.
authors.forename: Stella K
authors.initials: SK
authors.lastname: Kang
authors.forename: Ekin A
authors.initials: EA
authors.lastname: Turan
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Eisenberg
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Lee
authors.forename: Chung Yin
authors.initials: CY
authors.lastname: Kong
authors.forename: Pari V
authors.initials: PV
authors.lastname: Pandharipande
mesh_terms: D015897:Comorbidity; D003198:Computer Simulation; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015994:Incidence; D052177:Kidney Diseases, Cystic / Q000175:diagnosis* / Q000401:mortality*; D008017:Life Expectancy; D008279:Magnetic Resonance Imaging / Q000401:mortality* / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009381:Neoplasms, Radiation-Induced / Q000401:mortality*; D016016:Proportional Hazards Models; D018570:Risk Assessment; D018571:Sentinel Surveillance; D016019:Survival Analysis; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000401:mortality* / Q000706:statistics & numerical data
keywords: Bosniak IIF renal lesions; CT; MRI; radiation exposure; renal cell carcinoma