Effects of Iodinated Contrast Agent on Diffusion Weighted Magnetic Resonance Imaging

Abstract

Purpose: To evaluate the effects of iodine contrast agent on diffusion signal intensity and apparent diffusion coefficient (ADC) in diffusion-weighted imaging (DWI) studies in MRI examination just after computed tomography (CT) contrast imaging. 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 mg I/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 mg I/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 mg I/mL) for CT scan, the signal intensity of DWI was significantly increased and ADC was significantly decreased.1 Conclusion: It is necessary to recognise the rate of decrease of ADC, because it is dependent on the density of iodine contrast agents.2

Effects of contrast agents on relaxation properties of 31P metabolites

“…While iopamidol is a widely used CT contrast agent not typically used in MRI, it has slow clearance kinetics, and hence, can still be present in the body 24 hours after a contrast enhanced CT scan. We have observed significant shortening of both T 1 and T 2 relaxation times in saline and PBS solutions, which is in good agreement with literature 12,14,28 . However, these effects are highly concentration dependent, with negligible impact in tissues when the contrast agent is diluted 13,29 .…”

“…We have observed significant shortening of both T 1 and T 2 relaxation times in saline and PBS solutions, which is in good agreement with literature. 12,14,28 However, these effects are highly concentration dependent, with negligible impact in tissues when the contrast agent is diluted. 13,29 Our results support this hypothesis, as after adding the prescribed clinical dose of Iopamidol (~2% concentration of contrast agent), it was not possible to observe any effect on the blood 1 H relaxation times.…”

Role of Diffusion Weighted Magnetic Resonance Imaging in Evaluation of Suspicious Breast Lesions

“…The calculated ADC value is clearly affected by the scanning parameters of TR, TE, and b value used for DWI (15) . That is the reason for the different cutoff values found for the discrimination of the malignant from benign lesions in the previous studies and in the current study.…”

The Role of Dual Energy CT in Evaluating Hemorrhagic Complications at Different Stages After Thrombectomy

“…Commonly, the issue can be resolved with a repeated CT examination within 1-3 days (12,15), which may postpone antithrombotic therapy or anticoagulation. Although iodine can affect several magnetic resonance sequences (16), hemosiderin-sensitive sequences can be used since it is unlikely that iodine could mimic hemorrhage on magnetic resonance imaging (17). By contrast, DECT is a simple and fast solution differentiating hemorrhage and contrast staining, avoiding the delayed time for a repeat examination and the limitations of magnetic resonance, such as contraindications and limited resource issues (7).…”