MRI Appearance of Primary Brian Tumors (Gliomas, high grade glioblastoma and low grade gliomas.)

The appearance of primary brain tumors on MRI, (go here). Note that a high grade glioma (e.g. Glioblastoma Multiforme or GBM) has a distinct appearance (compared to a brain met, a low grade glioma or a benign tumor) but generally a biopsy is necessary to be absolutely sure of the proper diagnosis (see typical glioblastoma here , here, here, here, here, herehere and below).

GBM's are notoriously fast growing tumors as note here.

the center of the tumor may contain dead cells (or necrosis) surrounded by a rim of growing tumor cells and this surrounded by swelling, edema or inflammation, glioblastoma grow so quickly they outgrow their blood supply and the center of the tumor becomes necrotic (see pic)

A low grade glioma or astrocytoma may show only a low density area (dark area) whereas high grade gliomas (Glioblastoma) usually show more contrast enhancement (white on the outside) and  necrosis in the middle (looks black on the MRI) as shown in the two images below.
brain_tumor_sx.jpg (7928 bytes) ana_astro.jpg (14398 bytes)
glioma_grade3_bmc_oct_2006.jpg (20174 bytes) A grade 3 glioma (sometimes called anaplastic astrocytoma) will have less necrosis in the center (compared to a grade 4 or glioblastoma) but still look more abnormal (more enhancement) than a low grade (grade 1 or grade 2) .

Low grade gliomas often recur, and at the time of the recurrence are higher grade (see pic of grade 1 that at the time of recurrence was grade 3)

another low grade oligodendroglioma with anaplastic features on MRI here and course calcifications on CT here

Appearance of a Glioblastoma on an MRI Brain Scan

mri_gbm1.jpg (8181 bytes)

mri_gbm2.jpg (9355 bytes)

note that a glioblastoma (above) looks more necrotic (gray area in the center, which contains dead or necrotic cells) than a low grade glioma  (shown below:)

lg_astro.jpg (10551 bytes)

Pictured at left is a low grade glioma ( Pilocytic Cerebellar Astrocytoma)   with noncontrast CT on the left and axial T2- weighted MRI on the right.) from Harvard radiology (for more pics go here.)

Picture of another low grade glioma


Malignant Glioma can appear as a complex cystic structure as noted on the left
occasionally a glioblastoma may appear as multiple separate tumors
and look metastatic disease (called a multicentric glioblastoma)