Effects of Iodinated Contrast Agent on Diffusion Weighted Magnetic Resonance Imaging
Received 16 January 2009; accepted 28 March 2009. published online 22 June 2009.
Rationale and Objectives
To evaluate the effects of iodine contrast agent on diffusion signal intensity and apparent diffusion coefficient (ADC) in diffusion-weighted imaging (DWI) studies in magnetic resonance imaging (MRI) examination just after computed tomography (CT) contrast imaging.
Materials and Methods
On a 1.5 T MRI scanner, ADC was calculated from the signal intensity of DWI (b = 0 and 1000) using phantoms filled with contrast agent (0, 4.5, 6.0, 9.0, 30, and 60 mgI/mL). We evaluated the signal intensities of DWI and ADC in 10 patients (3 women, 7 men, 35–68 years old) examined by MRI study less than 40 minutes after injection of 100 mL of iopamidol (300 mgI/mL) for CT study.
Results
The DWI signal increased until a CT value of 190 HU, but showed no changes above this value. The ADC decreased with increases in CT value. Less than 40 minutes after injection of iopamidol (300 mgI/mL) for CT scan, the signal intensity of DWI was significantly increased and ADC was significantly decreased.
Conclusions
It is necessary to recognize the rate of decrease of ADC, because it is dependent on the density of iodine contrast agents.
ABSTRACT