Magnetic Resonance Imaging (MRI) Practice Test

How do you calculate the dose of contrast for a patient weighing 176 lbs with normal kidney function?

1. 20 mL

2. 12 mL

3. 10 mL

4. 16 mL

The correct answer is: 16 mL

To determine the appropriate dose of contrast for a patient weighing 176 lbs with normal kidney function, it is essential to consider standard dosing guidelines that often use a patient’s weight as a factor. Common recommendations suggest a dosage of contrast material typically ranges from 1 to 2 mL per kilogram of body weight for an average MRI scan. First, it is necessary to convert the patient’s weight from pounds to kilograms, as the dosing calculations are generally made in metric units. The conversion factor is that 1 kg is approximately 2.2 lbs. Therefore, the weight in kilograms for a patient weighing 176 lbs is calculated as follows: 176 lbs ÷ 2.2 = 80 kg (approximately). Next, using the typical dosing range of 1 to 2 mL per kg, you can calculate the dosages: - At 1 mL per kg, the dose would be 80 mL. - At 2 mL per kg, the dose would be 160 mL. However, for a specific scenario like this one, it is plausible that the required contrast agent is lower for routine procedures or for certain specific protocols that don't necessitate the maximum dose. Therefore, the calculated figure should fall within the