title: Does body mass index outperform body weight as a surrogate parameter in the calculation of size-specific dose estimates in adult body CT?
abstract: OBJECTIVE
  To assess the value of body mass index (BMI) in comparison with body weight as a surrogate parameter for the calculation of size-specific dose estimates (SSDEs) in thoracoabdominal CT.
  
  
  METHODS
  401 CT examinations in 235 patients (196 chest, 205 abdomen; 95 females, 140 males; age 62.5 ± 15.0 years) were analysed in regard to weight, height and BMI (kg m(-2)). Effective diameter (Deff, cm) was assessed on axial CT images. The correlation between BMI, weight and Deff was calculated. SSDEs were calculated based on Deff, weight and BMI and lookup tables were developed.
  
  
  RESULTS
  Overall height, weight, BMI and Deff were 172.5 ± 9.9 cm, 79.5 ± 19.1 kg, 26.6 ± 5.6 kg m(-2) and 30.1 ± 4.3 cm, respectively. There was a significant correlation between Deff and BMI as well as weight (r = 0.85 and r = 0.84; p < 0.05, respectively). Correlation was significantly better for BMI in abdominal CT (r = 0.89 vs r = 0.84; p < 0.05), whereas it was better for weight in chest CT (r = 0.87 vs r = 0.81; p < 0.05). Surrogated SSDEs did not differ significantly from the reference standard with a median absolute relative difference of 4.2% per patient (interquartile range 25-75: 3.1-7.89, range 0-25.3%).
  
  
  CONCLUSIONS
  BMI and weight exhibit a significant correlation with Deff in adult patients and can be used as surrogates in the calculation of SSDEs. Using the herein-developed lookup charts, SSDEs can be calculated based on patients' weight and BMI.
  
  
  CONCLUSIONS
  In abdominal CT, BMI has a superior correlation with effective diameter compared with weight, whereas weight is superior in chest CT. Patients' BMI and weight can be used as surrogates in the calculation of SSDEs.
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Boos
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Rotem S
authors.initials: RS
authors.lastname: Lanzman
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Heusch
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Joel
authors.initials: J
authors.lastname: Aissa
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schleich
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Thomas
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Lino M
authors.initials: LM
authors.lastname: Sawicki
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Dusseldorf, Germany.
authors.forename: Patric
authors.initials: P
authors.lastname: Kröpil
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001835:Body Weight; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011860:Radiography, Abdominal; D013902:Radiography, Thoracic; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult