1. Brain Neoplasm

2. Benign –May have aggressive tendencies –May transition to more aggressive lesion –Tends to be slower growing Primary malignant –Age distribution for various tumors –Impact due to mass effect or invasion Metastatic –History of pre-existing neoplasm –May be primary presentation Brain MRI modality of choice

3. Astrocytoma Irregular low attenuation lesion (CT) Isodense to gray matter central area Relatively ‘low grade’ Surrounding edema (black)

4. Astrocytoma MRI Parietal lesion White representing surrounding edema on T2 images Contrast enhancement on T1+C T2 T1 T1+C

5. Meningioma Medial posterior mass adjacent to the meninges Slow growing Minimal mass effect Intense enhancement T1+C T1 T2

6. Meningioma Extra-axial lesion Impact based on mass effect May be quite large without symptoms

7. Cystic Astrocytoma Cystic mass in posterior fossa Rim and mural nodule enhancement on contrast – far right image at arrows

8. Metastatic Brain Tumor Multiple ring enhancing lesions Brain edema (white rim T2) Known lung cancer T2T2 PDPD T1T1 T1+ C

9. Lung Neoplasm Nodule upper right lung field Patient with brain metastases