Emergency Cranial Radiological Assessment The Society of Neurological Surgeons Bootcamp

Objectives Identify basic intracranial structures Identify brain shift, intracranial hemorrhage, and skull fractures Be able to communicate accurately to the chief resident or attending the important findings that may impact clinical decision making and emergent patient management. The Society of Neurological Surgeons

CT Scan Bone Window Soft Tissue Window

Foramen ovale Foramen spinosum Carotid canal Jugular fossa # Left sphenoid bone – medial to foramen ovale, extends across carotid canal. Mastoids O.K. Mastoid air cells The Society of Neurological Surgeons

Sphenoid sinus Carotid canal The Society of Neurological Surgeons # Left sphenoid bone – medial to foramen ovale, extends across carotid canal. Mastoids O.K. The Society of Neurological Surgeons

Cisterns Suprasellar Interpeduncular Ambient

Caudate Internal capsule Thalamus Choroid Plexus

CT Scan Computerized Axial Tomography or CT scan is the most often used emergency imaging study in neurosurgery. A CT scan is an excellent study for identifying intracranial hemorrhage and skull fractures. Calcified structures such as bone or the pineal gland appear white or hyperdense. Acute blood clot appears white or hyperdense. Chronic hematomas appear dark or hypodense. Ischemic strokes are hard to identify on CT until they are about 6 – 12 hours old.

Hematomas Epidural Hematoma (EDH) Subdural Hematomas (SDH) Subarachnoid Hemorrhage (SAH) Intracerebral Hemorrhage (ICH) Intraventricular Hemorrhage (IVH)

Epidural Hematoma Between the skull and the dura. Biconvex or lens shaped. More common in children and young adults. Uncommon in the elderly since the dura is very adherent to the skull. Over 90% are associated with a skull fracture. Classically due to laceration of the middle meningeal artery. Initial concussion - “lucid interval” - deterioration Treatment is usually emergent surgery.

Case Example: 6 year old girl, MVA, GCS 7T, LOC at scene, lucid interval, now with lethargy and left side weakness Taken to OR for emergent evacuation of EDH The Society of Neurological Surgeons

Acute SDH More likely to be “crescent shaped” than “lens shaped”. Often holohemispheric. Can extend along falx or tentorium. Does not cross the midline. Higher morbidity and mortality than EDH due to additional underlying brain injury. 50-90% mortality.

Subdural Hematoma: Clot age and CT Imaging Characteristics Acute Subacute Chronic

Chronic SDH 50% without significant history of trauma Hypodense/isodense crescent shaped collection Evacuate if symptomatic Looks like motor oil Often occurs in the elderly on aspirin, plavix, or coumadin Can be treated by twist drill craniostomy, burr hole or craniotomy

Subarachnoid Hemorrhage

Subarachnoid Hemorrhage: Pattern Recognition ACoA Aneurysm Perimesenchephalic syndrome Diffuse SAH

Traumatic SAH 55 year old male, fell off ladder, no LOC, mild headache Repeat head CT stable, discharged next day with routine follow up

Intracerebral Hemorrhage: Chronic Hypertension

Intracerebral Hemorrhage Hypertensive IPH 50% in basal ganglia 15% thalamus 10-15% pons

IPH, IVH, Acute Hydrocephalus The Society of Neurological Surgeons

Lobar Intracerebral Hemorrhage:

Intraventricular Hemorrhage Frontal Horn Temporal Horn Lateral Ventricle FrontalThird Fourth Occipital Horns

Intraventricular Hemorrhage Aneurysmal SAH w/ IVH HTN w/ IVH

Traumatic Contusions Coup or contra-coup contusion Hemorrhagic contusions can enlarge or “blossom” as well as develop extreme edema, so must follow examination closely and consider repeat CT scans Surgical evacuation if there is excessive mass effect

47 year old gentleman, was inebriated, fall, LOC, GCS 7T (E2, M4, V1T), PERRL, In cervical collar EVD placed, Medical management of ICP, gradually improved over several days, neck cleared after extubation and improvement in neuro status The Society of Neurological Surgeons

18 year old male, shot in head while sitting in car, GCS 15 with no focal deficits, open scalp wound over skull fracture Scalp debrided, bullet fragment extracted, wound closed

Acute Hydrocephalus 7 year old boy with posterior fossa tumor, drowsy, less responsive through the day EVD EVD placed, immediately better

Ischemic Stroke Typically follow a vascular distribution such as the territory of the MCA, PCA or ACA. A stroke may take several hours before it is apparent on a CT scan. Typically is seen earlier on an MRI

MCA Infarcts

Infarct with a Midline Shift

Cerebral Edema Loss of Grey/White Differentiation Cisternal Effacement Midline Shift

Cerebral Edema Vasogenic: from brain tumor Cytotoxic: from trauma BBB disrupted Responds to steroids Cytotoxic: from trauma BBB closed NO steroids

Basal Cistern Effacement Normal Tight Swollen Brain

49 y/o male, MVA GCS 3T with fixed/dilated pupils No improvement, pronounced brain dead 24 hours later

Fractures Linear Depressed Open Depressed Basal Skull Fracture

Depressed Skull Fracture

Open Depressed Skull Fracture

Open Depressed Skull Fracture s/p MVA

Reconstruction

Basilar Skull Fracture

Basilar Skull Fracture of the Temporal Bone Seen on Bone Windows

Basic Principles of MR Imaging Images are created based on signals returning from spinning protons Not based on density Objects are described in terms of intensity (hypointense, isointense, hyperintense) T1 and T2 Weighted Imaging T1 Post Contrast Enhancement

T1 Weighted Image of the Normal Brain

T2 Weighted Image of the Normal Brain

MRI: Views in different planes Axial Sagittal Coronal

T1 Post Gadolinium Image of a Brain Tumor

Diffuse Axonal Injury (DAI)

Magnetic Resonance Imaging: Stroke Diffusion Weighted Imaging: Ischemia Cytotoxic edema Increase in signal as soon as 5-10 minutes after stroke onset Left: DWI Right: ADC map