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Relaxometry of noncalcified human meningiomas. Correlation with histology and solids content
S S Kasoff1, M Spiller, M P Valsamis
1Department of Neurosurgery, New York Medical College, Valhalla 10595, USA.
Rationale And Objectives:
Resected meningiomas were examined by relaxometry and light microscopy to evaluate the potential of magnetic resonance imaging (MRI) for identifying histologic subtypes and for discriminating among benign, radiation therapy-induced, and malignant meningiomas.
Methods:
The magnetic field dependence of 1/T1 of water protons (nuclear magnetic relaxation dispersion [NMRD] profile) and the water content (dry weight) were measured for 67 specimens, and the data were compared with histology. Only noncalcified, nonhemorrhagic meningiomas are reported.
Results:
No correlations were found between NMRD profiles, dry weight, and any histologic subtype, in contrast to an analogous study of astrocytomas. Rather, meningiomas have a broader variability of dry weight and 1/T1 than related parenchyma but a much narrower range than all grades of astrocytomas. The mean value of 1/T1, at all fields, is slightly higher in meningiomas--and the mean water content about the same--as adult cortical gray matter.
Conclusion:
Meningiomas are frequently isointense with cortex, and histologic subtypes cannot be differentiated at any magnetic field strength by MRI using only T1- or proton density-weighted MRI.
Insights
Magnetic resonance imaging (MRI) cannot differentiate meningioma subtypes or grades using relaxometry. Histologic subtypes of meningiomas were not identifiable by MRI in this study.
Area of Science:
- Neuroimaging
- Oncology
- Biophysics
Background:
- Meningiomas are tumors arising from the meninges.
- Accurate preoperative grading and subtyping of meningiomas are crucial for treatment planning.
- Magnetic resonance imaging (MRI) is a primary diagnostic tool for brain tumors.
Purpose of the Study:
- To assess the potential of magnetic resonance imaging (MRI) relaxometry for identifying meningioma histologic subtypes.
- To differentiate benign, radiation therapy-induced, and malignant meningiomas using MRI.
- To correlate MRI findings with light microscopy and histologic subtypes.
Main Methods:
- Sixty-seven resected meningioma specimens were analyzed.
- Measurements included water proton magnetic field dependence (nuclear magnetic relaxation dispersion [NMRD] profile) and water content (dry weight).
- Data were compared with histologic classifications, excluding calcified or hemorrhagic samples.
Main Results:
- No significant correlations were found between NMRD profiles, dry weight, and specific histologic subtypes.
- Meningiomas exhibited greater variability in dry weight and 1/T1 compared to brain parenchyma but less than astrocytomas.
- Mean 1/T1 and water content were comparable to adult cortical gray matter.
Conclusions:
- Histologic subtypes of meningiomas are not distinguishable by MRI at any magnetic field strength.
- T1- or proton density-weighted MRI sequences alone are insufficient for differentiating meningioma subtypes.
- Meningiomas often appear isointense with the cerebral cortex on MRI.