Correlation between Body Mass Index and Radiation Dose in Patients Undergoing Coronary Computed Tomography Angiography

ABSTRACT Background: Radiation dose is an important factor in performing a coronary Computed Tomography Angiography (CTA). Objective: To assess the correlation between Body Mass Index (BMI) and radiation dose in patients receiving a Coronary CTA. Methods: All retrospectively EKG gated coronary CTA studies using a 64 slice CT in patients above 18 years old, during a one-year time period were included in the study. The data was obtained by a query of the PACS system. Sixteen of the total 75 subjects were excluded due to lack of BMI or Dose length product (DLP) data or the CTA deviated from standard protocol. Seven of these patients were specifically excluded by using an x-ray tube voltage other than the standard 120 kVp. For the remaining 52 subjects, correlation and linear regression statistical analysis was used to analyze the relationship between BMI and DLP. Pearson correlation coefficient was calculated using Microsoft Excel. Results: There was a weak correlation between the BMI and DLP with a coefficient of determination value of 0.0217. Conclusion: When appropriate criteria exist for obtaining a coronary CTA, a high BMI should not deter ordering based only on high radiation dose concerns since correlation between BMI and DLP is weak.