2. Anoxic Brain Injury Findings:
Hypodense cerebral hemispheres with effacement of cortical gyri
Relative sparing of cerrebellum
Due to global insult:
Profound hypotension
Carbon monoxide poisoning
MRI findings:
Dense basal ganglia

5. Synovial Cyst of the Lumbar Spine
Findings:
Low T1, high T2 extradural lesion contiguous with the facet joint
Surrounding enhancement
Mass effect
Associated with degenerated joints – 75% at L4-5
Typically posterolateral
Contents variable – clear fluid, calcium, hemorrhage
ddx:
Migrated herniated disc
Perineural cyst (close to nerve root)
Schwannoma (low sig capsule)
Hematoma

7. Diffuse Axonal Injury Findings: Diffuse brain swelling
Focal punctate hemorrhage scattered in the white matter, corpus callosum, and brain stem
Right subgaleal hematoma
Due to diffuse shearing injury, sudden deceleration (MVA)
MRI findings:
Hemorrhage best seen on GRE sequence

9. PCOM aneurysm clipping anterior choroidal artery infarct
Findings:
Recent right pterional surgery
Aneurysm clips at PCOM
Low attn at the right genu of internal capsule = infarct
Pt wakes up with hemiparesis
Devastating complication of PCOM aneurysm clipping

11. Cavernoma of the Spine Findings:
“popcorn-like” intramedullary lesion in the conus
T2: faint high signal
T2: high signal centrally, dark rim, and high signal peripherally
a.k.a. Cavernoma, cavernous hemangioma, and capillary hemangioma
Congenital abnormal cluster of capillaries and venules that periodically bleed
Signal characteristics are that of blood in different stages
Angiographically occult
Look for multiple lesions on GRE

13. Inverting Papilloma Findings:
Soft tissue mass involving the maxillary sinus and nasal cavity
Expansion of sinus with bone remodeling, not destruction
Benign tumors of the lateral nasal wall which extend in to the maxillary and/or ethmoid
Can homogeneously enhance
Look for widening of the infundibulum
ddx:
Antrochoanal polyp
Mucocele

15. Nerve root avulsion and pseudomeningocele
Findings:
Abnormal high T2 signal dumbbell-shaped lesion in a high thoracic neural foramen
Mass effect on thecal sac
Large high T2 collection in the adjacent soft tissues
A result of major trauma
Disruption of the meninges and spill of CSF into surrounding tissues
Focal collection at the nerve root may appear as a discrete mass and displace thecal sac

17. Herpes Encephalitis Findings
Bilateral temporal lobe FLAIR signal (post-seizure edema)
HSV 2 in neonates
HSV 1 in adults
latent infection in the Gasserian ganglion (CN V)
predilection for the limbic syste, cingulate gyrus, and subfrontal region
late stage becomes bilateral, hemorrhage

19. Cortical Laminar Necrosis
Findings:
Cortical calcification of the posterior right MCA territory
Due to infarction
If global, think of hypoxic injury, hypoglycemia, or encephalitis

21. Primary Intracerebral Lymphoma
Findings:
T2 bright lesion in the left frontal lobe and basal ganglia
Crosses both gray and white matter
Some mass effect
No significant enhancement
An unusual lesion in the non-HIV/immunosuppred population
ddx:
Low –grade glioma

23. Spinal Sarcoid Findings:
Iso T1, hyper T2, enhancing lesion of cervical spinal cord
No significant cord expansion
Idiopathic system disease characterized by non-caseating granulomas
Young, black women
Image the brain, check CXR
ddx:
Transverse myelitis
Demyelinating dz (MS)
Primary cord tumor (ependymoma, astrocytoma)
Met (uncommon)

25. Septic Sacroiliitis Findings:
Low T1, high T2 abnormality in the right SI joint
Uncommon infection usually due to strep
ddx:
Unilateral
Gout
Osteoarthritis
Bilateral & symmetric
Ankylosing spondylitis
Inflammatory Bowel Dz
Bilateral & asymmetric
Psoriatic arthritis
Reiter syndrome
Rheumatoid

27. MCA hemorrhagic infarction
Findings:
Large hemorrhage in the right insula
Much surrounding edema
Some mass effect
Due to M1 segment embolus affecting lateral lenticulostriate arteries
ddx:
Hypertensive hemorrhage (usually little or no edema)
Underlying tumor or AVM (need angio to confirm)

29. Spinal Multiple Sclerosis
Findings:
Cord edema
Flame-shaped intramedullary enhancement
No significant cord expansion
Image the brain, check the optic nerves
ddx:
Transverse myelitis
Sarcoid
Primary cord tumor
Mets

31. Sacral Insufficiency Fracture
Findings:
High T2 signal in the left sacral ala crossing the midline and involving the right side
Normal stress on abnormal bone (usually osteoporosis)
Pts can have non-specific back or hip pain
Plain films show lucency, then sclerosis
Bone scan show classic “Honda sign”
ddx:
acute fractures
metastases

33. Lymphoepithelial cysts in HIV
Findings:
Enlarged parotid glands containing innumerable small cystic lesions
Manifestation in HIV, unclear etiology
Soft, non-tender enlarged glands
ddx:
Sjogren’s syndrome
Warthin’s tumors

35. TB meningitis Findings: High attenuation of the cerebellar folia
Look for the primary site (lungs); usually a post-primary infection
Long and protracted illness rather an typical sx of acute bacterial meningitis
Look for BASAL involvement
ddx:
Carcinomatous meningitis
Sarcoidosis
Lymphoma
Subarachnoid blood

37. Anaplastic Astrocytoma
Findings:
Ill-defined T2 signal abnormality involving both gray and white matter
Crosses vascular territories and into corpus callosum
Mass effect on ventricle
The most common primary brain tumor
Tumor margin likely beyond T2 boundary
Don’t let lack of enchancement fool you!

39. Spinal Dural AVF Findings: Expanded, edematous cord
Multiple extramedullary high signal foci
Direct AV communication leads to venous hypertension, cord congestion, and infarction
Extramedullary AVFs DO NOT bleed
Intramedullary AVMs have a nidus, present in kids as acute paresis due to spontaneous hemorrhage
ddx:
Leptomeningeal carcinomatosis

42. Rathke’s Cleft Cyst Findings:
High T1 & T2 slightly expansile sellar lesion
Displaces normal pituitary tissue
Non-neoplastic remnants of Rathke’s pouch
majority are asymptomatic, symptoms include visual defects, pit insufficiency, headaches
Can be high or low T1 but always high T2
Ddx:
Arachnoid cyst
Epidermoid
Pituitray adenoma
craniopharyngioma

46. Carotid body paraganglioma
Findings:
Intensely enhancing mass in the carotid sheath that splays the internal and external carotid arteries
ddx:
Glomus vagali
Carotid aneurysm

49. Glioblastoma multifome
Findings:
Aggressive intra-axial enchancing mass lesion with central necrosis
ddx:
Abscess
Tumafactive MS

51. Pathologic compression fracture & cord compression
Findings:
Compression of T11 with retropulsion and cord compression
Diffuse abnormal signal in the visualized vertebrae
Causes:
Metastases
Multiple myeloma

54. Pinealoblastoma Findings:
Large, aggressive, enhancing lesion of the pineal region
ddx:
Germinoma
High grade glioma
Metastasis

56. Juvenile Pilocytic Astrocytoma
Findings:
Cystic cerebellar lesion with enhancing mural nodule
Obstructive hydrochephalus
ddx:
Hemangioblastoma (in adults = think VHL)

58. Parotid pleomorphic adenoma
Findings:
Intensely bright T2 parotid lesion
ddx:
Adenoid cystic tumor
Mucoepidermoid
hemangioma

60. Isodense subacute subdural hematoma
Findings:
Isodense subdural hematoma
Much mass effect
ddx:
Hyperacute hemorrhage