Appearance of Meningiomas on Diffusion-weighted Images: Correlating Diffusion Constants with Histopathologic Findings
Christopher G. Filippi
,a,
Mark A. Edgara,
Aziz M. Ulua,
Joan C. Prowdaa,
Linda A. Heiera and
Robert D. Zimmermana
a From the Departments of Radiology (C.G.F., A.M.U., J.C.P., L.A.H., R.D.Z.) and Pathology (M.A.E.), The New York Presbyterian Hospital-Weill Medical College of Cornell University, New York, NY.
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FIG 1. Images of patient (patient 4 in the Table) with a malignant meningioma (WHO grade III).
A, Axial T1-weighted image (500/12/1) shows a well-marginated, recurrent extraaxial mass in the parietal convexity.
B, Axial fast spin-echo T2-weighted image (3000/84/1) of this recurrent meningioma appearing isointense to cortex.
C, Axial fast fluid-attenuated inversion recovery image (10002/162/1) shows isointense mass with smooth borders at resection site and no evidence of brain invasion.
D, Contrast-enhanced spin-echo T1-weighted image (450/12/1) shows smooth, homogeneous enhancement and dural enhancement typical of meningiomas.
E, Diffusion-weighted image (10000/99/1) of the recurrent meningioma, which is hyperintense (lightbulb).
F, Meningioma is hypointense on the ADC map, and the Dav was extremely low (0.45 x 10-5 cm2/s).
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FIG 2. Images of a patient (patient 9 in the Table) with a benign meningioma (WHO grade I).
A, Axial T1-weighted image of right temporal meningioma with "pseudocapsule" sign.
B, Axial fast spin-echo T2-weighted image shows that the mass is slightly hyperintense to cortex.
C, Fast fluid-attenuated inversion recovery image shows mass to be hyperintense to cortex.
D, Contrast-enhanced T1-weighted image shows intense, homogeneous enhancement.
E, Mass is predominantly isointense/slightly hyperintense on the diffusion-weighted image.
F, On the ADC map, the mass appears isointense/hyperintense to cortex, with a diffusion constant value (0.93 x 10-5 cm2/s) that is slightly elevated compared with normal brain parenchyma.
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FIG 3. Images of a patient (patient 14 in the Table) with a benign meningioma, distinct histopathologic subtype.
A, Axial T1-weighted image shows left frontal extraaxial mass with smooth margins and pseudocapsule sign.
B, Fast spin-echo T2-weighted image of the mass is isointense to cortex, with areas of hypointensity.
C, Fast fluid-attenuated inversion recovery image shows that the mass is isointense to cortex.
D, Homogeneous enhancement and "dural tail" are seen on the contrast-enhanced axial T1-weighted image.
E, Diffusion-weighted image shows that the meningioma is hypointense.
F, On the ADC map, the lesion is predominantly hyperintense, with areas of isointensity. The diffusion constant of this meningioma was elevated (1.07 x 10-5 cm2/s). This is greater than a 25% elevation compared with normal brain parenchyma. Histopathologic analysis revealed that this represented a secretory meningioma, which produces brain parenchymal edema (seen best by the fast fluid-attenuated inversion recovery) and which has prominent pericytic proliferations.
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