Effect of Body Mass Index on Effective Dose in Multi Detector Computed Tomography Abdomen Using Automatic Exposure Control

Abstract

BACKGROUND: Computed Tomography (CT) of the abdomen is one of the most frequently performed scans in adults for various abdominal pathologies. Its popularity stems from the immediate image reconstruction following acquisition. However, CT scans are known for their high radiation doses compared to other diagnostic X-ray procedures. This study aimed to analyze the effective dose in patients with varying body habitus during multidetector CT of the abdomen using automatic exposure control.

METHODS: This prospective study was conducted in the Department of Radiodiagnosis and Imaging from February 2017 to March 2018. Patients aged 18 and older, regardless of gender, undergoing routine Contrast-Enhanced CT (CECT) of the abdomen were included. Participants were categorized into three groups based on Body Mass Index (BMI): normal weight, overweight, and obese.

RESULTS: A total of 168 patients were enrolled, with a mean age of 49.8 ± 15.6 years, predominantly male (66.1%). Obese individuals exhibited significantly higher effective dose values (16.57 ± 2.27 mSv) compared to normal weight (9.45 ± 0.92 mSv) and overweight individuals (11.88 ± 0.77 mSv) (p < 0.01). Similarly, obese patients had significantly higher values for Computed Tomography Dose Index Volume (CTDIvol) (18.32 ± 2.54 mGy) and Dose Length Product (DLP) (1104.86 ± 151.84 mGycm) compared to normal weight (CTDIvol: 11.38 ± 1.24 mGy; DLP: 630.55 ± 61.57 mGycm) and overweight individuals (CTDIvol: 13.56 ± 1.15 mGy; DLP: 792.37 ± 51.56 mGy*cm) (p < 0.05).

CONCLUSION: The effective dose received by obese patients during abdominal CT exams with Automatic Exposure Control (AEC) is nearly double that of normal-weight patients.