Diffusion-Weighted MR Imaging: Diagnosing Atypical or Malignant Meningiomas and Detecting Tumor Dedifferentiation
Open Access
- 20 March 2008
- journal article
- Published by American Society of Neuroradiology (ASNR) in American Journal Of Neuroradiology
- Vol. 29 (6), 1147-1152
- https://doi.org/10.3174/ajnr.a0996
Abstract
BACKGROUND AND PURPOSE: Atypical and malignant meningiomas are uncommon tumors with aggressive behavior and higher mortality, morbidity, and recurrence compared with benign tumors. We investigated the utility of diffusion-weighted (DW) MR imaging to differentiate atypical/malignant from benign meningiomas and to detect histologic dedifferentiation to higher tumor grade. MATERIALS AND METHODS: We retrospectively compared conventional and DW MR images (b-value 1000 s/mm2) acquired on a 1.5T clinical scanner between 25 atypical/malignant and 23 benign meningiomas. The optimal cutoff for the absolute apparent diffusion coefficient (ADC) and normalized ADC (NADC) ratio to differentiate between the groups was determined by using receiver operating characteristic (ROC) analysis. RESULTS: Irregular tumor margins, peritumoral edema, and adjacent bone destruction occurred significantly more often in atypical/malignant than in benign meningiomas. The mean ADC of atypical/malignant meningiomas (0.66 ± 0.13 × 10−3 mm2/s) was significantly lower compared with benign meningiomas (0.88 ± 0.08 × 10−3 mm2/s; P < .0001). Mean NADC ratio in the atypical/malignant group (0.91 ± 0.18) was also significantly lower than the benign group (1.28 ± 0.11; P < .0001), without overlap between groups. ROC analysis showed that ADC and NADC thresholds of 0.80 × 10−3 mm2/s and 0.99, respectively, had the best accuracy: at the NADC threshold of 0.99, the sensitivity and specificity were 96% and 100%, respectively. Two patients had isointense benign tumors on initial DW MR imaging, and these became hyperintense with the decrease in ADC and NADC below these thresholds when they progressed to atypical and malignant meningiomas on recurrence. CONCLUSIONS: ADC and NADC ratios in atypical/malignant meningiomas are significantly lower than in benign tumors. Decrease in ADC and NADC on follow-up imaging may suggest dedifferentiation to higher tumor grade.This publication has 30 references indexed in Scilit:
- The contribution of diffusion-weighted MR imaging to distinguishing typical from atypical meningiomasNeuroradiology, 2006
- Diagnosis and Treatment of Atypical and Anaplastic Meningiomas: A ReviewNeurosurgery, 2005
- The Added Value of the Apparent Diffusion Coefficient Calculation to Magnetic Resonance Imaging in the Differentiation and Grading of Malignant Brain TumorsJournal of Computer Assisted Tomography, 2004
- Meningiomas in Singapore: demographic and biological characteristics.Journal of Neuro-Oncology, 2000
- Relationships Between Choline Magnetic Resonance Spectroscopy, Apparent Diffusion Coefficient and Quantitative Histopathology in Human GliomaJournal of Neuro-Oncology, 2000
- Inverse correlation between choline magnetic resonance spectroscopy signal intensity and the apparent diffusion coefficient in human gliomaMagnetic Resonance in Medicine, 1999
- Usefulness of diffusion-weighted MRI with echo-planar technique in the evaluation of cellularity in gliomasJournal of Magnetic Resonance Imaging, 1999
- MR diffusion imaging of human intracranial tumoursNeuroradiology, 1997
- MRI of intracranial meningiomas: correlations with histology and physical consistencyNeuroradiology, 1993
- The growth rate of intracranial meningiomas and its relation to histology. An analysis of 43 patientsSurgical Neurology, 1985