Abdominal DSCT Effectiveness of Contrast Media Dose on Basis of BMI

Dual-source CT (DSCT) offers fast, high-quality abdominal imaging(1), but consistent contrast enhancement can vary with patient size(2). Body mass index (BMI) significantly influences contrast distribution, potentially leading to suboptimal imaging in obese patients. This study explores the effectiveness of adjusting contrast media dose based on BMI, aiming to achieve uniform enhancement, reduce iodine usage, and improve diagnostic accuracy across varying body types in abdominal DSCT imaging(3) . Research investigates the effectiveness of adjusting iodinated contrast media doses in abdominal CT scans based on lean body weight instead of total body weight. Traditional dosing overlooks individual body composition, often leading to underdosing in muscular or lean individuals and overdosing in obese patients. By adopting a lean body weight-based approach, this study aims to enhance image quality, ensure diagnostic accuracy, and reduce unnecessary contrast exposure(4). Computed tomography (CT) is a popular imaging modality in medicine since it may detect several disorders. Contrast media whether intravenous, oral & rectal, enhance image quality of abdomen. Contrast enhancement may not always be necessary and can pose dangers. Contrast enhancement is usually acceptable for the presumed diagnosis. When the diagnosis is unknown, using contrast can be beneficial, but the dangers should be considered(5–10). All modern contrast agents contain iodine. Iodine produces enhanced absorption and scattering of incoming radiation, increasing the tissue or organ's attenuation or "brightness". Oral contrast can assist identify the bowels from other abdominal tissues(11). Oral contrast comes in two varieties: neutral and positive. Water or a dilute, low-attenuation fluid that resembles water make up neutral oral contrast. Positive oral contrast is an iodinated (e.g., Gastrografin) or barium-based solution with high attenuation that opacities the colon. The introduction of multidetector CT, which provides higher resolution, has made it simpler to distinguish abdominal structures without the use of pacification with positive oral contrast(3,12–16).     

Objectives-

To evaluate the BMI of the patient preferred for CECT. Assessment of contrast dose with the help of BMI, to assess the image quality of CECT abdomen.

METHODS

Study Type

This was a cross-sectional observational study, aimed at evaluating the effectiveness of contrast media dose in abdominal DSCT based on patients' body mass index (BMI).

Study Design

The study was designed prospectively, applying a uniform imaging protocol to all enrolled patients undergoing elective contrast-enhanced CT (CECT) of the abdomen.

Study Area

The research was conducted at the Department of Radio-Diagnosis and Imaging, SRMS Institute of Medical Sciences, Bareilly, Uttar Pradesh.

Study Duration

Data collection spanned a total of 6 months, including a broad range of clinically indicated abdominal imaging cases.

Study Population

All patients referred for CECT abdomen during the study period were considered for inclusion, excluding those undergoing emergency scans. Final eligibility was determined based on clinical indications and exclusion criteria.

Method of Data Collection

CT imaging was performed using both 128-slice and 32-slice dual-source scanners. Each patient underwent arterial and portal venous phase imaging. Demographic and scan-related data such as age, sex, weight, height, BMI, tube voltage (kV), current (mA), contrast volume, concentration, injection rate, and duration were documented. BMI was categorized using WHO criteria. Contrast enhancement was measured by calculating the difference in Hounsfield Units (HU) in liver segment IV between non-contrast and portal venous images. Aortic enhancement of ≥211 HU during the arterial phase was considered diagnostically adequate. Regions of interest (ROIs) were consistently placed, measuring approximately 1–2 cm²(17).

Setting and Resources

The study used the existing imaging infrastructure at SRMS IMS. Patient anthropometric measurements were recorded using calibrated devices. Imaging analysis was conducted via the institutional PACS system by qualified radiology staff.

Statistical Analysis

The final sample size was set at 94 participants. Data analysis included descriptive and comparative statistics across BMI groups, with a significance level of p < 0.05.

Ethical Considerations

The study protocol received approval from the Institutional Ethical Committee (IEC) of SRMS, IPS/IMS, Bareilly. Ethical Clearance Certificate Reference No-SRMS/IPS/ECC/2022/029.

RESULTS

The age distribution of patients is shown in the table 1 and figure1. There are four age group divisions: 11–30, 31–50, 51–70, and above 71. Patient in the 51–70 age range creates the largest age group i.e. 38% of total patients included in this study. The Ages 31 to 50 creates the second largest age group i.e. 33% and Patients above 71 create the smallest age group i.e. 4% of total patients included in this study. The mean age of patients is 23.5 years, with a standard deviation of 14.1 years. This shows that the sample's average age is 23.5 years, with individual members' ages varied by about 14.1 years from this average.

Table 1: -Distribution of patients according to their age group

Figure 1: - Distribution of patients according to their age group

Data on the distribution of genders within a patient, including frequencies and percentages for each sex, are shown in the table and Figure2.The percentages show how many people in each sex there are in relation to the 94 overall sample size. At 61% of the patients as male and three-nine percent of patients are female.

Table 2: - Distribution of patients according to their gender group

Figure 2: - Distribution of patients according to their gender group

The Table and Figure 3 show frequencies and percentages for each weight category and offer information on the weights distributed between a patients. The 61–80 is the weight group with the largest frequency, making up 49% of the all. The weight range of 41–60, comprise 41% and the weight categories 40 and >81 are 4% and 5%. The mean weight is 63.07 units, with a 12.58-unit standard deviation.

Table 3: - Distribution of patients according to their weight group.