MRI
MRI has superior soft tissue
resolution and is a valuable imaging modality in the evaluation of a
calvarial mass. MR imaging features are critical in characterizing the
lesion as benign versus malignant neoplasm and non-neoplastic. MRI is
necessary in evaluation of the lesion extent, especially for
intracranial extension to include dural and parenchymal invasion.19. As discussed for
orbital tumors, DWI is very helpful in characterizing the cellularity of
the lesion and thereby honing benign and malignant differential
considerations. The soft tissue component of the tumor in the scalp may
be obscured by the subcutaneous fat, especially on the postcontrast T1WI
with enhancing tumors displaying similar signal as the surrounding fat.
Fat suppression (FS) is often performed to overcome this issue and
allows better delineating of the lesion. The arterial and venous anatomy
can be demonstrated on MRA and MR venography (MRV). MRA can display the
arterial supply of the lesion. MRV is useful in assessment of the dural
venous sinus involvement when the lesion is adjacent a dural venous
sinus. MRA and MRV are considered
optional.