Kathleen R. Fink, MD Virginia Mason Medical Center. 6 th Nordic Emergency Radiology Course 2017

Transcription

1 Kathleen R. Fink, MD Virginia Mason Medical Center 6 th Nordic Emergency Radiology Course 2017

2 Disclosure My spouse receives research salary support from: Guerbet

3 Outline Indications for imaging CNS infections Extra axial Parenchymal Vascular complications

4 Indications for Imaging Suspected infection and: Altered mental status Seizures Focal neurologic deficits Immunocompromised patient with: New headache Any concerning sign

5 Imaging strategy Non contrast head CT first choice Rapid and widely available Well tolerated by critically ill patients Exclude life threatening conditions Contrast enhanced MR More sensitive for subtle findings - Leptomeningitis - Ventriculitis - Empyema - Infarction Consider strongly for immunocompromised patients Can be problematic in sick patients Contrast enhanced head CT if: MR not immediately available Contraindications to MR

6 Imaging before LP? Noncontrast CT can exclude contraindications CT more likely to show a contraindication in patient with (suspected meningitis) and: Age 60 Immunocompromise Recent seizure Focal neurological deficit Impaired consciousness Hasbun 2001 N Engl J Med 345:24,

7 Not safe to LP Cerebral edema: Poor gray-white differentiation Effaced sulci Effaced cisterns

8 Contraindications to LP No absolute consensus on imaging contraindications. General agreement on the following: Midline shift Effacement of the basal cisterns Posterior fossa mass effect. Clinical signs of herniation even with normal imaging.

9 Cautionary tale 4 PM, comatose 8 PM, after LP

10 Extraaxial

11 8 year old boy, sick one week

12 8 year old boy, sick one week Acute bacterial meningitis Post contrast

13 Imaging in meningitis CSF evaluation is diagnostic Goal of imaging: 1) Exclude unexpected finding 2) Evaluate for complications: - Infarction - Hydrocephalus - Ventriculitis - Subdural effusions (kids), empyema - Venous sinus thrombosis

14 Meningitis: Imaging Imaging Findings: NORMAL Especially early Leptomeningeal enhancement Hemispheric Basilar Subdural effusions (especially children) Ddx leptomeningeal enhancement: Leptomeningeal spread of tumor Neurosarcoidosis CNS lymphoma

15 MRI: index case DWI/ADC T1 FLAIR

16 Meningitis: MRI Imaging Findings: FLAIR: high signal in subarachnoid space due to elevated protein May see arterial narrowing due to infectious arteritis with or without infarction Ddx: Subarachnoid FLAIR hyperintensities: Subarachnoid hemorrhage High inspired O2 Motion artifact Altered perfusion/blood brain barrier disruption Leakage of gad (renal failure, eg)

17 19 yo with worsening headache, nausea, and vomiting. NECT Hydrocephalus!!

18 MRI DWI/ADC FLAIR T1 post

19 Tuberculous meningitis Basilar meningitis: Can present with hydrocephalus due to thick inflammatory exudate Intracranial tuberculoma Granulomatous lesions Caseating or noncaseating +/- necrotic center Tuberculous abscess Complications: Vasculitis, infarcts Patkar Neuroimaging Clin N Am 22:4,

20 Key Imaging Features CT Normal Hydrocephalus Isodense exudate in basilar cisterns MR Enhancing basilar leptomeninges Infarcts Tuberculomas: Solid, nodular or ring enhancement

21 Image Gallery DWI T1 post Complications: Infarcts

22 Basilar meningitis T1 post T1 pre Ddx: basilar meningitis: Tuberculous meningitis Pyogenic meningitis Fungal meningitis Neurosarcoidosis Meningeal carcinomatosis

23 Tuberculous meningitis Basilar meningitis + infarcts: TB meningitis Fungal meningitis, including coccidioidomycosis Basilar meningitis + parenchymal lesions Think TB.

24 53 year old man with recurrent facial cellulitis, treated with antibiotics.

25 Subdural empyema T1 T2 T1 Post ADC

26 Subdural empyema: CT: Isodense collection Subdural empyema, DDX: Chronic Subdural hematoma Subdural effusion (sterile CSF collection associated with meningitis) Subdural hygroma Dural based mets MRI: T1 isointense (i.e proteinaceous material) T2 hyperintense +/- restricted diffusion (dark ADC) Peripheral and meningeal enhancement May see underlying cerebritis (as in this case)

27 Epidural abscess Usually associated with head and neck infection: Sinusitis Otomastoiditis Post trauma + Post Surgery * Subdural empyema and Epidural abscess can occur together. MRI may help differentiate.

28 Parenchymal

29 History: Feeling poorly for 3 weeks, bizarre behavior x 1 day, seizure

30 History: Feeling poorly for 3 weeks, bizarre behavior x 1 day, seizure FLAIR

31 Herpes Encephalitis Location: Anterior and medial temporal lobes Insula Lateral temporal lobes Inferior frontal lobes Cingulate

32 Key imaging features Normal -OR- Edema (low density) Hemorrhage Petechial Along brain surface Burned out: Gliosis CT Restricted diffusion may be first FLAIR MRI GRE for microhemorrhages May enhance Tien et al AJR Am J Roentgenol 161:1,

33 Image gallery FLAIR NECT DWI

34 Chronic changes of HSV encephalitis

35 Differential diagnosis: Ischemia (including venous infarction) Neoplasm Limbic encephalitis Other viral encephalitis (e.g. arboviral) Favor HSV: Bilateral Nonvascular distribution Normal basal ganglia

36 Arbovirus infection Pathogenic viruses: Eastern equine Western Equine West Nile Japanese Tick-borne Basal ganglia and thalami lesions T2, FLAIR, DWI Ddx deep white matter: Anoxic/hypoxic injury CO2, toxic exposures Metabolic disorders (eg Wilson s disease) Mitochondrial diseases Creutzfeldt Jacob Eastern equine encephalitis. Case courtesy of Mahmoud Mossa-Basha, MD

37 History: 39 year old who fell Current Study Comparison from 9 months prior

38 MRI

39 HIV-associated neurocognitive disorders (HAND) Direct result of HIV on CNS Findings on CT and MRI do not predict cognitive dysfunction CT: Normal Volume loss: sulcal or ventricular enlargement Patchy white matter hypodensities

40 HIV-associated neurocognitive disorders (HAND) MRI: Symmetric white matter disease May resemble age-related volume loss or white matter lesions of vascular origin, but more than expected for age Spares Juxtacortical u- fibers

41 HIV-associated neurocognitive disorders (HAND) FLAIR T2

42 Key Imaging Features: HIV T1: occult DWI T1 post: Non-enhancing

43 Differential Diagnosis Age-related volume loss; white matter lesions of presumed vascular origin (chronic ischemic change) Hydrocephalus Progressive multifocal leukoencephalopathy

44 History: 43 year old with HIV and low CD4 count who presents with gait disturbance

45 T1 T1 post T2 DWI

46 Progressive Multifocal Leukoencephalopathy PML Seen in certain clinical scenarios: HIV Severe immunosuppression Multiple sclerosis on natalizumab

47 PML Imaging findings Low density CT and T2 hyperintense areas Little mass effect or contrast enhancement Parietal, occipital lobes Asymmetric

48 Features favoring a diagnosis of PML over HIV Involvement of subcortical u- fibers PML HIV

49 PML Confluent lesions, favors parietooccipital or CC Involves juxtacortical U fibers HIV Normal or patchy periventricular centrum semiovale lesions Spares U fibers Asymmetric Symmetric Low on T1 Low on DWI unless active demyelination Does not enhance unless IRIS (immune reconstitution inflammatory syndrome) Usually isointense on T1 Isointense on DWI No enhancement Sahraian. European Journal of Neurology 2012, 19: doi: /j x

50 Image Gallery Posterior fossa involvement

51 Image Gallery PML IRIS DWI NECT ADC T2 T1 post

52 History: 33 year old with nausea, vomiting and right sided weakness

53 Neurocysticercosis Taenia solium, pork tapeworm Cyst with central dot Central dot is scolex Four pathologic stages: Simple cyst complex cystic lesion calcification

54 Stage CT Findings MR Findings Noncystic (Active asymptomatic) Normal Normal Vesicular (Cyst or cluster of cysts with scolex) Colloidal vesicular (Larva degenerates, inflammatory response begins) Granular nodular (Cyst retracts and granulomatous reaction ensues) Calcified nodular (Inactive) 1-2 cm cyst Simple appearing fluid No edema. Scolex Cyst may be dense Enhances ± Edema Edema increases. Thick ring enhancement Calcific nodules without edema or enhancement Thin-walled cyst Follows CSF Little enhancement. Scolex Proteinaceous cyst Thick walled Edema Enhancement Edema increases. Thick ring enhancement Hypointense nodules without edema or enhancement Kimura-Hayama Radiographics 2010 Oct;30(6): doi: /rg

55 Key Imaging Features DWI NECT ADC T2 T1 post

56 Image Gallery Subarachnoid Calcified nodular phase Intraventricular cysts can cause hydrocephalus.

57 Differential Diagnosis Pyogenic abscess (no scolex) Ring enhancing mass: Metastasis Glioblastoma multiforme Lymphoma in immunocompromised patient Etc.

58 History: 38 year old with recurrent sinus infections, worsening headache, nausea and vomiting + Contrast

59 MRI: DWI T1 ADC FLAIR T1 post

60 Pyogenic abscess Focal pus collection with surrounding capsule. Direct extension Sinusitis Otomastoiditis Odontogenic Hematogenous IVDA Endocarditis Pulmonary AVF

61 Pyogenic abscess Parenchymal mass Gray-white junction Low T2 ring Hyperintense necrotic core Rim enhancement Thick smooth Thinned medial wall Restricted diffusion of central necrotic core Daughter cells Look for ventricular extension

62 Image gallery

63 Cerebritis 2 days later DWI FLAIR FLAIR T1 post T1 post

64 Abscess development 13 days later Early cerebritis Ill defined edema Late cerebritis Central low density Early capsule Thin rim enhancement Britt J Neurosurg 1983 December;59(6): Late capsule Thick rim enhancement

65 History: 40 yo with HIV and 2 days of headache, blurry vision, gait disturbance

66 MRI: Vital in Immunocompromised

67 Toxoplasmosis Toxoplasma gondii Reactivation of latent infection in immunocompromised patient Masses: Eccentric target sign: Specific not sensitive Ring enhancing T2 heterogeneous No restricted DWI of central necrotic portion Location: Basal ganglia Thalamus Gray-white junction Akgoz et al. Neuroimaging Clin N Am 22:4,

68 HIV patient with mental status change DWI FLAIR ADC

69 Cryptococcus Cryptococcus neoformans Associated with HIV infections Can affect immunocompetent patients Presents as Meningitis Meningoencephalitis Cerebral vasculitis Imaging may be normal.

70 Cryptococcus Imaging patterns: Meningeal enhancement Basilar meningitis Masses: cryptococcomas Granulomas Basal ganglia predominant May enhance (immunocompetent) Choroid plexus Gelatinous exudate: Dilated perivascular spaces Pseudocysts

71 Image Gallery DWI T1 FLAIR ADC T1 post T2

72 Image gallery: C. gatti Dilated VR spaces Cryptococcomas of choroid plexus

73 Differential Diagnosis Tuberculous meningitis Cryptococcus meningitis Coccidioidal meningitis

74 Vascular complications

75 54 yo, aortic valve replacement, new headache NECT CTA

76 Conventional Angiogram 2 months prior Current Right ICA injection

77 Mycotic aneurysm New peripheral (distal MCA) aneurysm Unusual location for saccular aneurysm Treatment is resection * methicillin-sensitive staphylococcus aureus

78 Infectious vasculitis: S. pneumo meningitis Initial T2 2 wks later

79 Septic emboli

80 Outline Indications for imaging CNS infections Extra axial Parenchymal Vascular complications

81 Thank you! Kathleen Fink