MRI Protocol for Skull-Based Meningioma

Essential MRI Sequences

The American College of Radiology recommends using a standardized MRI protocol that includes high-resolution 3D T1-weighted sequences pre- and post-contrast, axial T2 FLAIR, diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI), and axial T2-weighted sequences for skull base meningioma diagnosis 1, 2
3D T1-weighted gradient echo pre-contrast provides baseline anatomic detail and high-resolution imaging for small lesion detection, as suggested by the American College of Radiology 1, 2
3D T1-weighted post-contrast is the single most important sequence for meningioma visualization, demonstrating characteristic homogeneous dural-based enhancement, dural tail, and CSF cleft, according to the American College of Radiology 1, 3
Axial T2 FLAIR is essential for demonstrating the CSF cleft between tumor and brain, evaluating vasogenic edema in adjacent parenchyma, and confirming extraaxial location, as recommended by the American College of Radiology 1, 4
Axial DWI with ADC maps provides information about tumor cellularity, though meningiomas typically show variable diffusion characteristics, as noted by the American College of Radiology 1, 5
Axial SWI is critical for detecting intratumoral calcifications, which occur in up to 50% of meningiomas, and for visualizing intratumoral blood products, according to the American College of Radiology 1, 3

The American College of Radiology suggests considering MR perfusion (DSC) as an adjunct for skull base meningiomas when grading is important, as meningiomas are highly vascular tumors and perfusion can help predict WHO grade 1, 3, 4
SSTR PET (DOTATATE, DOTATOC, or DOTANOC) is particularly valuable for skull base meningiomas because morphologic tumor borders are difficult to assess by MRI alone in this location, as noted by the European Journal of Nuclear Medicine and Molecular Imaging 6, 7
Specific indications for adding SSTR PET include ambiguous MRI findings, treatment planning, suspected optic nerve sheath meningioma, and differentiating recurrence from post-treatment scar tissue, according to the European Journal of Nuclear Medicine and Molecular Imaging 6, 7

Classic meningioma characteristics include homogeneous dural-based enhancement with characteristic dural tail, CSF cleft between tumor and brain parenchyma, intratumoral calcifications visible on SWI sequences, and vasogenic edema in subjacent parenchyma on T2/FLAIR, as described by the American College of Radiology 1, 2, 3
Red flags for meningioma mimics include marked T2-hypo- or hyperintensity, absence of dural tail, and dural displacement sign rather than dural attachment, as noted by the American College of Radiology 1

The American College of Radiology advises against relying on CT alone for skull base meningiomas, as CT has significantly inferior sensitivity compared to MRI and frequently misses small lesions, particularly in the internal auditory canal or cerebellopontine angle 3
The American College of Radiology recommends not skipping contrast administration unless contraindicated, as post-contrast T1-weighted imaging is essential for optimal tumor delineation 1, 4
The American College of Radiology suggests not omitting SWI sequences, as calcifications are common (up to 50% of cases) and provide important diagnostic information 3