RINGS N THINGS: Imaging Patterns in Differential Diagnosis. Anne G. Osborn, M.D.

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1 RINGS N THINGS: Imaging Patterns in Differential Diagnosis Anne G. Osborn, M.D.

2 ExpDDxs: Intra-axial (Parenchymal) Lesions Ring-enhancing lesions, solitary 1 Ring-enhancing lesion crossing corpus callosum Ring-enhancing lesions, multiple Ring-enhancing cyst with nodule 1 Smirniotopoulos JG et al: Patterns of contrast enhancement in the brain and meninges. Radiographics 27: , 2007

3 SOLITARY RING ENHANCING LESION: Does M.A.G.I.C.A.L. DR. Really Work? Mnemonic 1 Metastasis Abscess/cerebritis Glioblastoma Infarct (resolving), Impact Contusion AIDS toxoplasmosis Lymphoma (AIDS-related) Demyelinating Disease Radiation necrosis, Resolving hematoma 1 Dahnert W: Radiology Review Manual, 5 th edition, p LWW (2003)

4 Well, Not really.. Common Metastasis Abscess GBM Less common Hematoma (subacute) Infarct (subacute) Tumefactive demyelination NCC Lymphoma TB Radiation necrosis Less common (contd) Aneurysm (thrombosed) AVM (thrombosed) Rare but important Lacunar infarct (subacute) Fungal diseases Parasites

5 RING-ENHANCING LESION: The Big Three Neoplasm Metastasis GBM Infection Abscess TB Parasite Demyelinating disease M.S. ADEM

6 METASTASIS Gray-white junction Solid, ring, punctate Multiple > single

7 ABSCESS Imaging depends on stage Ring = late cerebritis, early/late capsule Findings Rim T2 hypointense Thin, enhancing rim Restricts on DWI MRS: Acetate, lactate, succinate, cytosolic amino acids

8 GLIOBLASTOMA MULTIFORME 95% Central necrosis Thick, irregular rind Strong, inhomogeneous enhancement DWI negative (usually) Hemorrhage common Beware: Tumor infiltates way beyond

9 MET VS. ABSCESS Metastasis Superficial > deep (graywhite) Multiple > solitary Usually no restriction DWI Abscess Deep (periventricular) Restricts on DWI MRS acetate, lactate amino acids TR2000/TE35

10 SOLITARY RING: Less Common Etiologies Subacute hematoma Demyelination Subacute infarct Giant thrombosed aneurysm

11 SOLITARY RING: Less Common Etiologies NCC TB Lymphoma (HIV/AIDS) TB

12 SOLITARY RING: Less Common/Rare Etiologies Thrombosed AVM Radiation necrosis Fungal disease Parasites

13 SOLITARY RING: Summary and Helpful Hints Restricts? Think infection Hypointense center on T2? TB HIV+ patient? 70% = lymphoma Looks weird? Think parasites MRS shows lactate + peaks at 2 and 0.9 ppm? Think abscess Older patient with thick, irregular ring? GBM

14 RING-ENHANCING LESION CROSSING CORPUS CALLOSUM Common Glioblastoma multiforme Lymphoma Less common Tumefactive demyelinating disease

15 GLIOBLASTOMA MULTIFORME Crosses CC in butterfly pattern Central necrosis heterogeneous ring enhancement Hemorrhage common DDx: Lymphoma (especially HIV/AIDS)

16 Often periventricular Basal ganglia Corpus callosum Ventricular ependyma Very cellular Hyperdense on NECT Isointense to GM on MR (T2 hypointense) Enhancement Usually homogeneous Can be ring-like in HIV/AIDS LYMPHOMA

17 TUMEFACTIVE DEMYELINATING DISEASE MS > ADEM White matter mass mimics neoplasm BUT Incomplete ring or horseshoe enhancement Open towards cortex

18 MULTIPLE RING- ENHANCING LESIONS Common Metastases Abscesses/septic emboli Demyelinating disease Neurocysticercosis Less common TB Opportunistic infection (HIV/AIDS) Lymphoma GBM (multifocal) Less common Resolving hemorrhages Resolving embolic infarcts Rare but important Fungal disease Parasites Lyme disease (? demyelination)

19 METASTASES Multiple ringenhancing lesions Tend to be at graywhite junction Variable edema, hemorrhage No restriction on DWI (usually.) Breast mets Lung mets

20 MULTIPLE ABSCESSES: Septic Emboli Punctate, complete or incomplete rings Gray-white junction Often appear to encase sulcus Restrict on DWI

21 MULTIPLE ABSCESSES: Septic Emboli

22 DEMYELINATING DISEASE MS, ADEM cause multifocal ring-enhancing lesions Usually incomplete May show diffusion restriction along periphery

23 NEUROCYSTICERCOSIS Common disease Ring enhancement in colloidal vesicular, granular nodular stages Multiple enhancing rings uncommon Most are around cysts trapped in depths of sulci Parenchymal lesions less common

24 LESS COMMON CAUSES OF MULTIPLE RINGS: Tuberculosis Clue to dx = profound hypointensity on T2WI, FLAIR

25 OTHER LESS COMMON, RARE RINGS HIV/AIDS (toxo) Parasites Nocardia Subacute infarcts (laminar necrosis or embolic)

26 RING-ENHANCING CYSTIC LESION WITH NODULE Common (Neurocysticercosis) Pilocytic astrocytoma Ganglioglioma Hemangioblastoma Less common Metastases GBM Abscess Toxoplasmosis Parasites Rare but important Pleomorphic xanthoastrocytoma Lymphoma (HIV/AIDS) Schwannoma (intraparenchymal)

27 PARENCYHMAL NEOPLASMS THAT COMMONLY HAVE ENHANCING RING + NODULE PXA Pilocytic astro Ganglioglioma Hemangioblastoma

28 LESS COMMON NEOPLASMS Metastasis Lymphoma (HIV/AIDS) Schwannoma GBM

29 NONNEOPLASTIC ENHANCING RING + NODULE Toxoplasmosis (HIV/AIDS) Parasites (amebic) AVM (thrombosed) Tuberculoma

30 RING-ENHANCING CYST + NODULE: Diagnostic Hints Age Child? Posterior fossa: Pilocytic astrocytoma Hemisphere: Ganglioglioma Adult? Posterior fossa?? Met, met, met then hemangioblastoma! Hemisphere: Metastasis, GBM HIV/AIDS? Toxoplasmosis, lymphoma Patient from endemic area? Neurocysticercosis (sulci > parenchyma) Parasites TB Dural involvement? PXA!