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MR imaging of high-grade cerebral gliomas: value of diffusion-weighted echoplanar pulse sequences
R D Tien1, G J Felsberg, H Friedman
1Department of Radiology, Duke University Medical Center, Durham, NC 27710.
Objective:
The purpose of this study was to evaluate the usefulness of diffusion-weighted echoplanar MR imaging in the examination of high-grade brain gliomas compared with that of conventional spin-echo (SE) or fast spin-echo (FSE) MR imaging. We hypothesize that diffusion-weighted MR imaging may enable us to differentiate various tumor components on the basis of differences in the diffusion of water.
Subjects And Methods:
Conventional SE and FSE MR images were obtained in 10 patients with high-grade brain glioma. Diffusion-weighted echoplanar MR images were obtained with a head gradient coil capable of providing diffusion-weighted imaging along the cephalocaudal axis. Using SE and FSE MR images as a baseline, we evaluated the diffusion-weighted MR images for usefulness in distinguishing tumor components on the basis of differences in diffusion.
Results:
Areas of tumor that showed significant enhancement on T1-weighted SE MR images obtained after injection of contrast material were markedly hyperintense on diffusion-weighted images and had a lower apparent diffusion coefficient (ADC) than the ADCs for nonenhancing tumor and peritumoral edema. Cystic or necrotic portions of tumor showed the most signal suppression on diffusion-weighted images and were associated with the highest ADCs. On T2-weighted FSE MR images, areas of hyperintensity observed in white matter oriented parallel to the direction of the diffusion gradient could be differentiated into two patterns on the basis of findings on diffusion-weighted images: areas that showed marked signal suppression with a higher ADC, most likely representing areas of predominantly peritumoral edema, and areas that showed a lesser degree of signal suppression with similar but slightly lower ADCs than those of edema, most likely representing areas of predominantly nonenhancing tumor.
Conclusion:
Diffusion-weighted echoplanar MR imaging is a useful technique for examining high-grade cerebral gliomas. It enabled us to differentiate various components of the tumor (e.g., enhancing, nonenhancing, cystic, or necrotic) and to distinguish areas of predominantly nonenhancing tumor from areas of predominantly peritumoral edema when the abnormality was located in the white matter aligned in the direction of the diffusion-weighted gradient. Diffusion-weighted echoplanar MR imaging appears to be a powerful tool in the characterization of brain neoplasms.
Insights
Diffusion-weighted echoplanar MRI effectively differentiates high-grade brain glioma components. This advanced imaging technique distinguishes enhancing, nonenhancing, cystic, and necrotic tumor areas, improving characterization of brain neoplasms.
Area of Science:
- Neuroimaging
- Radiology
- Oncology
Background:
- High-grade brain gliomas are aggressive tumors requiring accurate characterization.
- Conventional MRI techniques like spin-echo (SE) and fast spin-echo (FSE) have limitations in differentiating tumor components.
- Diffusion-weighted imaging (DWI) offers insights into tissue microstructure by measuring water diffusion.
Purpose of the Study:
- To evaluate the utility of diffusion-weighted echoplanar MR imaging (DWI) for examining high-grade brain gliomas.
- To compare DWI's effectiveness against conventional SE and FSE MRI in distinguishing tumor components.
- To test the hypothesis that DWI can differentiate tumor parts based on water diffusion variations.
Main Methods:
- Conventional SE and FSE MRI were performed on 10 patients with high-grade brain glioma.
- Diffusion-weighted echoplanar MR images were acquired using a specialized head gradient coil.
- SE and FSE images served as a baseline for evaluating DWI's ability to distinguish tumor components.
Main Results:
- Enhancing tumor areas were hyperintense on DWI with lower apparent diffusion coefficients (ADCs) compared to nonenhancing tumor and edema.
- Cystic/necrotic tumor regions showed signal suppression on DWI and higher ADCs.
- DWI differentiated white matter abnormalities into peritumoral edema (high ADC) and nonenhancing tumor (slightly lower ADC).
Conclusions:
- Diffusion-weighted echoplanar MRI is a valuable tool for high-grade cerebral glioma assessment.
- DWI successfully differentiated tumor components like enhancing, nonenhancing, cystic, and necrotic areas.
- This technique aids in distinguishing nonenhancing tumor from peritumoral edema in white matter, enhancing brain neoplasm characterization.