title: Direct chest area measurement: A potential anthropometric replacement for BMI to inform cardiac CT dose parameters?
abstract: BACKGROUND
  Significant dose reductions for coronary CT angiography (CTA) can be achieved with reduced tube potential (kV); however, the potential effect on image quality is unknown.
  
  
  OBJECTIVE
  We sought to evaluate anthropometric measures (chest area, chest circumference, and chest attenuation) as potentially better predictors of the appropriate tube potential versus body mass index (BMI).
  
  
  METHODS
  Consecutive patients (n = 183) who underwent routine coronary CTA (with standard department protocols, whereby tube potential was selected according to BMI) between April 2010 and October 2010 were included. All anthropometric measures were obtained by tracing a region of interest encompassing an entire axial full field-of-view image at the mid left atrial level. Linear regression was used to stratify patients into 4 chest area classes (very small to large). Patients were also stratified by standard BMI classes (underweight to obese). Qualitative and quantitative image quality parameters were compared between concordant and discordant chest area and BMI classes.
  
  
  RESULTS
  A strong correlation was observed between patients' BMI and chest area (r = 0.84; P < 0.001) and between BMI and chest circumference (r = 0.82, P < 0.001). Concordance between chest area class and BMI class was found in 61%, whereas 17.6% of patients were "potentially underdosed" (chest area class > BMI class) and 21.4% were "potentially overdosed" (chest area class < BMI class). Signal and contrast of the proximal coronaries and left ventricle were significantly different between the groups.
  
  
  CONCLUSIONS
  Patients' chest area and BMI classes were frequently discordant, potentially leading to overdosing or underdosing when using BMI to select tube potential.
authors: Massachusetts General Hospital, 165 Cambridge St, Ste 400, Boston, MA 02114, USA.
authors: Brian B
authors: BB
authors: Ghoshhajra
authors: Leif-Christopher
authors: LC
authors: Engel
authors: Gyöngyi Petra
authors: GP
authors: Major
authors: Dan
authors: D
authors: Verdini
authors: Manavjot
authors: M
authors: Sidhu
authors: Mihály
authors: M
authors: Károlyi
authors: Suhny
authors: S
authors: Abbara
authors: Udo
authors: U
authors: Hoffmann
authors: Manudeep
authors: M
authors: Kalra
authors: Thomas J
authors: TJ
authors: Brady
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D016477:Artifacts; D015992:Body Mass Index; D001900:Boston; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D013909:Thorax / Q000033:anatomy & histology*; D014057:Tomography, X-Ray Computed