Comparison of ADC values of intracranial hemangiopericytomas and angiomatous and anaplastic meningiomas

Purpose: This study aimed to determine whether the use of apparent diffusion coefficient (ADC) values can improve the diagnostic efficacy of magnetic resonance imaging (MRI) to differentiate hemangiopericytoma (HPC) from angiomatous and anaplastic meningioma. Materials and methods: Preoperative diffusion-weighted imaging (DWI) studies of 38 patients with pathologically proven intracranial HPC (n = 12) and angiomatous (n = 13) or anaplastic meningioma (n = 13) were retrospectively reviewed. ADC values were measured in the tumor parenchyma and peritumoral edema, and used to obtain normalized ADC (NADC) ratios (ADC of tumor/ADC of normal white matter). Results: Mean ADC values were significantly different between HPC and anaplastic meningioma (1.17 +/- 0.30 x 10(-3) mm(2)/s and 0.75 +/- 0.11 x 10(-3) mm(2)/s, respectively). Mean NADC ratios were also significantly lower in the malignant cases (0.95 +/- 0.13) compared with the benign HPCs (1.53 +/- 0.39; P < 0.05). Mean ADC values and NADC ratios did not differ significantly between angiomatous meningioma and HPC (P > 0.05), whereas mean ADC values and NADC ratios were lower for anaplastic meningioma than for either angionnatous meningioma or HPC (P < 0.05). Mean ADC value in peritumoral edema in HPC (1.48 +/- 0.11 x 10(-3) mm(2)/s) was lower than in either angiomatous (1.73 +/- 0.28 x 10(-3) mm(2)/s) or anaplastic (1.72 +/- 0.25 x 10(-3) mm(2)/s) meningioma (P < 0.05), and there was no significant difference between ADC values in anaplastic versus angiomatous meningioma (P > 0.05). Conclusion: ADC values in tumor parenchyma and peritumoral edema can provide helpful information that is otherwise not available from conventional MRI to differentiate HPC from angiomatous and anaplastic meningioma. (C) 2013 Elsevier Masson SAS. All rights reserved.