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Half-dose gadolinium-enhanced MR imaging with magnetization transfer technique in brain tumors: comparison with
1Department of Radiology, Seoul National University College of Medicine, Korea.
Objective:
The purpose of this study was to determine whether half-dose enhanced MR imaging with magnetization transfer (MT) saturation can replace standard-dose enhanced MR imaging without MT saturation in patients who have brain tumors.
Subjects And Methods:
Three sets of enhanced T1-weighted MR images were prospectively obtained for each of 25 patients with 32 brain tumors; the first conventional MR images without MT were obtained after administration of standard-dose (0.1-mmol/kg) gadopentetate dimeglumine. Within 1 week, patients underwent administration of one half-dose (0.05 mmol/kg) of the contrast medium, and then two sets of enhanced T1-weighted images were obtained with and then without MT. The degree of contrast enhancement was assessed qualitatively for all 32 tumors and quantitatively for 26 tumors. In the quantitative analysis, we compared mean values for tumor-brain contrast-to-noise ratios in three sets of images.
Results:
The visual conspicuity of enhancing lesions in half-dose T1-weighted MR images with MT was comparable with that of standard-dose conventional T1-weighted MR images in 43% of cases including most extraaxial tumors. In approximately 75% of cases, the degree of enhancement of the lesions was similar for half-dose T1-weighted images obtained with and without MT. Overall, mean values for tumor-brain contrast-to-noise ratios were significantly lower in half-dose T1-weighted images with MT than in standard-dose T1-weighted images. Also, mean values for tumor-brain contrast-to-noise ratios were significantly higher in half-dose T1-weighted images with MT than in half-dose T1-weighted images without MT.
Conclusion:
Because half-dose enhanced MR imaging with MT yields enhancement comparable with that of standard-dose enhanced conventional MR imaging in less than 50% of cases, the former technique would replace the latter in only limited cases such as selected extraaxial tumors.
Insights
Half-dose enhanced MRI with magnetization transfer (MT) saturation is not a reliable replacement for standard-dose MRI in most brain tumor cases. This technique may be suitable for specific tumor types, such as extraaxial tumors.
Area of Science:
- Radiology
- Medical Imaging
- Neuro-oncology
Background:
- Enhanced MRI is crucial for diagnosing and monitoring brain tumors.
- Standard contrast doses may be reduced to minimize risks and costs.
- Magnetization transfer (MT) saturation is a technique that can potentially improve lesion conspicuity.
Purpose of the Study:
- To evaluate if half-dose enhanced MRI with MT saturation can substitute standard-dose enhanced MRI without MT saturation for brain tumor imaging.
- To compare the diagnostic performance of different MRI contrast enhancement protocols.
Main Methods:
- Prospective study involving 25 patients with 32 brain tumors.
- Acquisition of three sets of enhanced T1-weighted MR images: standard-dose without MT, and half-dose with and without MT.
- Qualitative and quantitative assessment of contrast enhancement and tumor-brain contrast-to-noise ratios.
Main Results:
- Half-dose enhanced MRI with MT showed comparable lesion conspicuity to standard-dose MRI in 43% of cases, particularly for extraaxial tumors.
- The degree of enhancement was similar in half-dose images with and without MT in approximately 75% of cases.
- Mean tumor-brain contrast-to-noise ratios were significantly lower with half-dose MT compared to standard-dose, but higher than half-dose without MT.
Conclusions:
- Half-dose enhanced MRI with MT saturation is not a universal replacement for standard-dose enhanced MRI for brain tumors.
- This technique may be considered for specific indications, such as selected extraaxial tumors.
- Further research may explore optimized protocols for reduced contrast administration in neuroimaging.