Imaging Neurologic Emergencies: When and Where Radiology Makes a Difference

Transcription

1 Imaging Neurologic Emergencies: When and Where Radiology Makes a Difference James G. Smirniotopoulos, M.D. Radiology and Radiological Sciences Uniformed Services University Bethesda, MD Learning Objectives Choose the best imaging for each patient Develop a checklist for imaging to improve your ability to identify significant findings Recognize imaging findings that will acutely change patient management Clinical Assessment History Headache, Seizure, Weakness, Visual Traumatic, non-trauma, found down Level of Consciousness Glasgow Coma Scale (GCS) Neurologic Examination Cranial Nerve Exam (CNN 2-12) Extremities moving all four?

2 Imaging Assessment What tests are on the menu? CT scans w/o contrast with contrast MR scans w/o contrast with contrast Special MR (e.g. Diffusion, Perfusion, etc.) What test should I get? Almost always a non-contrast CT scan Imaging Assessment What should I look for? Global Assessment for abnormalities Mass Effect, Brain Shift or Herniation BWH? Diagnosis and Etiology Traumatic Non-Traumatic Vascular (e.g. stroke ) Toxic/Metabolic Neoplastic Treatment Decisions Surgical vs. Conservative or Medical Management MR and CT Imaging Checklists Anatomic Locations Sagittal Images Sup. Sag. Sinus Corpus Callosum Sella Region Clivus Axial Images Skull, Epi/Sub Dural SAS Cortical Gray Matter White Matter Deep Gray Matter Ventricles Morphologic Features Mass Effect Yes, proportional Less than expected No mass effect Abnormal WM Signal Vasogenic Edema Demyelination Infiltrating neoplasm Enhancing Ring Lesion Necrotic Neoplasm Reactive (e.g. abscess) Fluid or Inflammatory

3 Autopsy History of Imaging Acute CNS Skull series plain films Angiography Gross mass lesions (EDH, SDH) Computed Tomography EDH, SDH, Contusion, some DAI Conventional Spin Echo MRI More of the above GRE/MSI, DTI, MRS, fmri Even more CNN 2: Blindness 45 y.o.. man with acute onset of right-sided homonymous hemianopsia R L L R Where would the lesion be? What we see - Findings Axial CT Abnormal Cortex and WM Where? Medial Occipital Lobe Minimal mass effect

4 Right Homonymous Hemianopsia: What the Patient Sees L R L R Non-Contrast CT PCA Infarct Lights up like a lightbulb on MRI DWI

5 Post. Cerebral A. Infarct Imaging Infarction CT abnormal in hours MR abnormal in minutes Insular ribbon sign Increased water Hyperdense MCA Hyperintense MCA Intraluminal clot Vascular (intravascular) enhancement DWI Bright ADC Dark Intracellular Cytotoxic Edema Carotid Thrombosis => MCA Clot ACA MCA X MCA PCA

6 This 53 yo man presented to the Emergency Department reporting a several hour history of left-sided hemi-body weakness medpix20366.jpg Repeat CT: Hyperdense MCA Repeat CT scans, two hours after admission Matching DWI and ADC Images = Cytotoxic Edema = Acute Infarct DWI Restricted Diffusion or T2 Shine- Thru? ADC Map

7 Cytotoxic Edema Normal Na+ K+ pump K goes In Na goes Out Energy Dependent Glucose O2 ATP Normal Neuron Swollen Dead Neuron Chronic Infarct Atrophy Complications of rtpa Two days after IA Thrombolysis

8 Whole MCA Infarction Acute Motor Hemiplegia BP on presentation 185/105 Courtesy Doug Phillips, UVA INTRA-CEREBRAL HEMORRHAGE Dense and Homogeneous Round/oval shape Basal ganglia/deep white Proportional mass effect Extension into ventricle

9 Hypertensive Hemorrhage BP on presentation 210/110 Courtesy Doug Phillips, UVA Hypertensive Hemorrhage Hypertensive hit list Basal Ganglia Internal/External Capsule Thalamus Dentate Nucleus Pons Lobar Courtesy Doug Phillips, UVA

10 Headache 39 y.o.. woman with abrupt onset of the worst headache of my life What we see - Findings Axial CT Abnormal Where? Subarachnoid space How? Hyperdense Worst HA: Non-Contrast CT

11 Aneurysm and Rupture Clinical Hx: "Worst Headache of My Life Nuchal Rigidity Photophobia Signs: Kernig s, Brudzinski's Demographics: Common Cause of Stroke in Young (< 40) Most pts yrs Risk Factors: Hypertension, ADPCKD, CTD (connective tissue) Subarachnoid Hemorrhage Subarachnoid Hemorrhage LP more sensitive than CT Trauma is most common cause for RBC S in CSF Not seen as easily or as often on CT SAH on CT Blood clot usually Aneurysm / AVM Uncommon from neoplasm Uncommon from spinal disease

12 Subarachnoid Clots

13 Aneurysm Round ( berry( berry ) ) shape Vessel bifurcation natural weakness exploited by high BP Common sites: ACA <-> < > ACOMM MCA branches Basilar Tip Angiography - Angiogram AP Oblique ICA Aneurysm T2WMR MRA

14 Pulsation Artifact Phase-encoding direction ICA Aneurysm Found Down 34 yo marine stationed at Guantanamo Bay Cuba, presenting w/ acute mental status changes, febrile. T2WMR

15 Abnormal Gray Matter Vascular Ischemia Infarction Hyperemia (Migraine, Seizures) Inflammatory Encephalitis Meningo-Encephalitis Vasculitis Abnormal Gray Matter T2WMR Vascular Follows territory of MCA, etc. Infection Multiple territories Non-Vascular» HSV Encephalitis ACA ACA MCA MCA

16 MCA ACA AChoA PCA 34 yo comatose woman, psychiatric pt. Courtesy Aimee Hawley, M.D. MGAFMC

17 Findings Intraaxial Diffuse Bilateral abnormalities Low attenuation in Cortical Gray Matter Low attenuation in Basal Ganglia Edema What Kind? Interstitial Cytotoxic Hydrostatic Toxic/Metabolic Lab: Serum Na+ 121 Psychogenic polydipsia Overhydration Athletes drinking too much water Iatrogenic D5W w/o salts Treatment Hypertonic Saline 2% saline (not 4%)

18 Causes of Hyponatremia Increased total body water Excessive water intake Iatrogenic (IV therapy) Reduced Urine Output Exercise Heat Exposure Inappropriate ADH Sodium Loss Inadequate Sodium Intake Treatment: Correction by administration of IV Saline, or twice normal, or Treatment of Hyponatremia Rapid Correction of serum Na+ T1W T2W DWI

19 Osmotic Myelinolysis What do they have in Common? Multiple Toxic and/or Metabolic: Bilateral Symmetric Acquired Anatomic Congenital Basal ganglia Metabolic Intrinsic Diabetic Ketoacidosis Hypoglycemic Coma Extrinsic Toxic Exposures CO and Methanol

20 Medial vs. Lateral Lenticular Carbon Monoxide Methanol Intoxication Carbon Monoxide Methanol Intoxication Medial vs. Lateral Lenticular CO Poisoning

21 Carbon Monoxide Intoxication CO Intoxication CO binds to Hgb 240X stronger than O 2 making carboxyhemoglobin Sx: : HA, Lethargy, weakness, dizziness, nausea, confusion, and SOB TX is to displace CO with O 2 T 1/2 for CO is 320 min on room air 80 min on 100% O 2 23 min at 3 atm 100% O 2 MetOH Intoxication

22 Tx for MetOH - Fomepazole Fomepazole (Antizole,, 4-methylperazole) 4 is a synthetic alcohol dehydrogenase inhibitor for IV administration Clear yellow liquid, mw 82.1, mp 25º C (77º F) INDICATIONS: Antidote for ethylene glycol, or methanol poisoning or suspected EG ingestion PRECAUTIONS: Dilute in > 100 ml NS, follow hepatic enzymes & WBC (eos( eos) ) during Rx, interaction with ethanol (compete for ADH) DOSE: 15 mg/kg load, 10 mg/kg Q 12 h x 4 doses, then 15 mg/kg Q 12 h till EG < 20 mg/dl Anoxia During Surgery Diffuse and Bilateral Gray-matter hypointensities Anoxia During Surgery Diffuse and Bilateral Gray-matter hypointensities

23 What we saw Trauma Epidural Hematoma => Brain Herniation Subdural Hematoma => Brain Herniation Vascular Acute Cerebral Infarction Spontaneous hypertensive Hematoma SAH from Ruptured Cerebral Aneurysm Infection Herpes Encephalitis Metabolic/Toxic Hyponatremia CO and MetOH Toxicity Summary Brain Herniation Epidural Subdural Trauma Ventricular blood Shearing Injury Gray matter Encephalitis Ischemia/Infarction Toxic/Metabolic Co vs. Methanol t f C U M T T t Go Raimh Maith Agat Thank You! Muito Obrigado EUXAPIΣTΩ! Mahalo! Dank u wel! Merci Beaucoup Danke Schön! Mil Gracias