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MR imaging with i.v. superparamagnetic iron oxide: efficacy in the detection of focal hepatic lesions
T C Winter1, P C Freeny, H V Nghiem
1Department of Radiology, University of Washington Medical Center, Seattle 98195.
Objective:
The purpose of this study was to evaluate the efficacy of superparmagnetic iron oxide (SPIO) in the detection of focal hepatic lesions on MR images.
Subjects And Methods:
The study included 21 patients with 115 focal hepatic lesions and eight patients without focal hepatic lesions. T1- and T2-weighted MR images were obtained at 1.5 T before and 60 min after the end of injection of an SPIO agent. Contrast-enhanced CT scans were obtained in all patients within 10 days after MR imaging. The effect of SPIO on the signal intensity of the liver and spleen was assessed by using quantitative analysis of the region of interest. Efficacy was evaluated by using multiple criteria and unenhanced and SPIO-enhanced images. Evaluations included subjective assessment of image quality, counting the number of lesions detected, and statistical analysis of quantitative changes in the signal intensity of lesions and of normal liver.
Results:
By all criteria, SPIO-enhanced T2-weighted MR images were superior to unenhanced T2-weighted images and to contrast-enhanced CT scans. Conversely, by all criteria, SPIO-enhanced T1-weighted MR images were worse than unenhanced T1-weighted images and contrast-enhanced CT scans. The mean lesion-to-liver contrast on T2-weighted images was 317% on unenhanced images and 1745% on SPIO-enhanced images. For T1-weighted, the mean contrast was 26% on unenhanced images and 18% on SPIO-enhanced images.
Conclusion:
SPIO is an efficacious contrast agent for the detection of focal hepatic lesions when T2-weighted MR images are used.
Insights
Superparamagnetic iron oxide (SPIO) enhanced T2-weighted MRI significantly improves the detection of focal hepatic lesions compared to unenhanced MRI and CT scans. SPIO-enhanced T1-weighted MRI was less effective.
Area of Science:
- Radiology
- Medical Imaging
- Hepatology
Background:
- Focal hepatic lesions require accurate detection for diagnosis and management.
- Magnetic Resonance Imaging (MRI) is a key modality for liver lesion assessment.
- Superparamagnetic iron oxide (SPIO) is an MRI contrast agent with potential for enhancing lesion detection.
Purpose of the Study:
- To evaluate the efficacy of SPIO contrast agent in detecting focal hepatic lesions using MRI.
- To compare the performance of SPIO-enhanced MRI with unenhanced MRI and contrast-enhanced CT.
Main Methods:
- 21 patients with hepatic lesions and 8 without underwent T1- and T2-weighted MRI before and after SPIO injection.
- Contrast-enhanced CT scans were performed for comparison.
- Quantitative analysis of signal intensity and lesion detection were used to assess efficacy.
Main Results:
- SPIO-enhanced T2-weighted MRI demonstrated superior performance over unenhanced T2-weighted MRI and CT scans.
- SPIO-enhanced T1-weighted MRI showed inferior results compared to unenhanced T1-weighted MRI and CT scans.
- Lesion-to-liver contrast increased significantly on SPIO-enhanced T2-weighted images (1745%) versus unenhanced (317%).
Conclusions:
- SPIO is an effective contrast agent for detecting focal hepatic lesions when used with T2-weighted MRI sequences.
- T2-weighted imaging is crucial for leveraging SPIO's benefits in hepatic lesion detection.