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Radiology and Pathology Teaching Points Sessions I and II. Pat Hudgins and Dan Brat. I.1: Golden Grapes. I – Case 1. A single image says it ALL!. Swollen edematous ON T2 information Expanded ON sheath Good old symmetry! Dirty intraconal fat Use of fat sat (FS) info - PowerPoint PPT Presentation
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Radiology and Pathology Teaching PointsSessions I and II
Pat Hudgins and Dan Brat
I.1: Golden Grapes
A single image says it ALL!
• Swollen edematous ON– T2 information
• Expanded ON sheath– Good old symmetry!
• Dirty intraconal fat– Use of fat sat (FS) info
• Lack of flow void in SOV– MR physics: moving spins
should give signal void
I – Case 1
Diffusion Weighted Imaging (DWI)
• Add diffusion gradients
• ↑ signal intensity (SI)– Real: √ ADC map– Artifact: T2 shine
through
• ADC map – dark
• True restricted diffusion
I – Case 1
Diffusion Weighted Imaging (DWI)
• Infarcted brain
• Pus
• Rare acute MS plaque
• Some high grade BT’s
• Some neoplasms
• Creuztfelt Jakob
• Misc infections
I – Case 1
• “Pus” is THE SHORTEST pathologic diagnosis (Purulent material is more appropriate)
• Stains for bacteria are NOT helpful for speciation
• When infectious disease is on the differential, specimen should be sent to Microbiology for cultures
I.2: Ain’t No Sunshine When You are Gone!
“T1 Ax Gd FS “I – Case 2
Imaging TechniquesPulse Sequence “Families”
Spin Echo Gradient Echo
I – Case 2
Fast Imaging Techniques
Siemens MP-RAGE VIBE
General Electric 3D Fast SPGR LAVA-XV
Philips 3D TFE THRIVE
I – Case 2
Fast Imaging Techniques
Gradient Echo – “Fast” Imaging
MP-RAGE
Magnetization Prepared Rapid Acquisition Gradient Echo
• 3 D, can do multiplanar reformats
• Isovoxel 1 mm x 1 mm x 1 mm
I – Case 2
Fast Imaging Techniques
Gradient Echo – “Fast” Imaging
Might look like a T1, but be careful
Disadvantages• Metal artifact is bad• WM very bright – can obscure
enhancing lesions• Cranial nerves often “enhance”
I – Case 2
Pilocytic Astrocytomas (grade I) involve the optic pathways more frequently than Infiltrative Astrocytomas (grades II-IV)
Anaplastic Astrocytoma (grade III) differs from grade II by the presence of mitoses and from Glioblastoma (grade IV) by its lack of necrosis.
Anaplastic Astrocytoma is generally fatal within 2-5 years.
I.3: Some Orbital Confusion
Initial MRI: T1 A and C
• Do we see Stuff or a Thing?• Diff Dx for Stuff:
– Pseudotumor– Infection (but fat clean)– Sarcoid– Lymphoma– We’ll add to this list
during the next sessions as weird rare lesions are presented
I – Case 3
Motion and MRI = NOT GOOD!I – Case 3
T2 images take longer to acquire than T1Adding fat saturation ↑↑ time of acquisition
Bone Algorithm Makes Crappy Soft Tissue!
I – Case 3
If lymphoma is a possibility, send fresh tissue for flow cytometry.
Marginal zone lymphoma is one type of low grade B-cell lymphoma. MALTOMA is most frequent.
Distinguished from follicular, mantle cell and small cell lymphoma by morphology and markers.
Antigen Status in
MZL
CD20 Positive
CD79a Positive
CD5 Negative
CD10 Negative
CD23 Negative
CD43 Negative
cyclin D1 Negative
I.4: A Wolf in Bear’s Clothing
Don’t underestimate CECT!I – Case 4
Gadolinium good, but over-rated!I – Case 4
Extramedullary Myloid Tumor and Chloroma are other terms
Remember Flow Cytometry!
Hematologic Malignancies can present in “liquid” or solid forms with identical cell types: Myeloid Sarcoma vs AML; SLL vs CLL
Myeloperoxidase expression is defining; also positive for CD68
Bone, soft tissue, skin and lymph nodes are most frequent sites
I.5: No Rhabdo?
CT vs MRII – Case 5
“Feathery” interface with intraconal fat implies intraconal extension!
Is the process intra-conal??I – Case 5
“Feathery” interface with intraconal fat implies intraconal extension!
MRI: T1 C Gd FS
• Fungal organisms (Zygomycoses, Aspergillus and Candida species) are readily identified in with silver stains
• Speciation based on stains is not generally advised.
• Send cultures
Session I: What have we learned?
1. In the right setting, DWI can change the dx!
Most MRI = anatomic, but DWI = physiology
2. Not every image with black CSF is true T1
Each new sequence has different limitations
3. Stuff vs thing = helps come up with DDx
4. Gd only one tool in the toolbox
5. A good CECT is another great tool
6. “Feathery” interface is intra-conal
Session I: What have we learned?
• If infection is a diagnostic consideration, send tissue for cultures; special stains are not optimal for speciation
• If hematologic malignancy is a diagnostic consideration, send tissue for flow cytometry and cytogenetics
• Both infiltrative and pilocytic astrocytomas can involve the optic pathways; pilocytics are much more frequent
II.1: Behind the Curtain
What can I say? Three separate lesions, should have been mets
Sometimes, you need a good pathologist!
II – Case 1
Pathologist’s view:Inflammatory pseudotumor is a non-satisfying diagnosis, usually one of exclusion
Mixture of chronic inflammatory cells and stromal response causing a mass (NOT “pseudo-”)
Combines many entities with variable outcomes
Unknown etiology; rule out lymphoma
II.2: Deaf and Dizzy. Have We Been Susacked?
Physiologic Imaging Trumps AnatomyII – Case 2
Physiologic Imaging Trumps AnatomyII – Case 2
• High grade B-cell lymphoma localized to vascular lumens
• Presents in the brain and skin most often• Multiple infarcts with variable distribution • Lymphoma unable to traverse blood brain barrier? • Dismal prognosis
Primary CNS Lymphoma Intravascular Lymphoma
II.3: It’s All In Your Head
“Stuff” differential got longer….II – Case 3
Histiocytoses Involving the CNS
CD68 S-100 CD1a Langerhans cell histiocytosis: + + +Rosai-Dorfman disease: + + -(sinus histiocytosis with massive emperipolesislymphadenopathy)Histiocytic sarcoma + - -Erdheim-Chester Disease + - -
lipid laden histiocytes with multinucleated cells
II.4: Is it Naughty or Nice?
If it looks like cotton…think MSII – Case 4
Stroke Demyelinating Disease
Most frequent cause of lawsuit in neuropathology is the misdiagnosis of demyelinating disease as a malignant astrocytoma
Macrophages are misinterpreted to be neoplastic astrocytes
Finding macrophages in a CNS biopsy should alert to non-neoplastic diseases, like MS or stroke (always atypical presentations)
CD68
II.5: A Difficult Bug to Swallow
T1 – Always look at anterior clinoidMets or meningioma
II – Case 5
Whole body PET not good for skull base
II – Case 5
Many patients present to medical attention with a metastatic carcinoma to the CNS without knowledge of a primary neoplasm.
Advances in imaging and immunohistochemical markers have made the search for a primary neoplasm much more successful.
TTF1/Napsin
Session II: What have we learned?
• Sometimes lesions don’t follow the “rules” Why did pseudotumor look like a thing?
• DWI is a great tool
• Erdheim-Chester likes the hypothalamus
• When you see cotton, think MS
• Orbital experts should use T1 images routinely, and put anterior clinoid process on your checklist!
Session II: What have we learned?
• Inflammatory pseudotumors are real diseases, but poorly understood and likely represent multiple etiologies.
• Intravascular lymphoma has similar malignant B-cells to primary CNS lymphoma, but trapped in blood vessels.
• Histiocytic infiltrates require subclassification based on morphology and markers.
• Fulminant cases of demyelinating disease can look like neoplasms radiologically and pathologically.
Have a Good Lunch
• Be back at 1PM
• We start promptly at 1:10PM