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.