Neuroradiology for psychiatrist

Computerized Tomography

• CT scans measure density of the tissues

• Hyperdense and hypodense refer to brighter and darker areas, respectively

• Structures of intermediate density similar to brain tissue appear gray and are called isodense

Non contrast

Contrast

What can be seen by CT scan

• Hemorrhage (EDH, SDH, SAH, ICH)• Infarction• Neoplasm• Mass effect• Infection ( meningitis ,

encephalitis , abscess )

Epidural hematoma (EDH)

• Traumatic brain injury• Bleeding between skull

and dura (artery bleeding)

• Appearance : Biconvex lens

• Clinical : headachefocal signcomadeath

Subdural hematoma (SDH)

• Usually associated with traumatic brain injury

• Bleeding between dura and arachnoid mater(venous bleening : bridging veins)

• Cresent- shaped on CT scan

• Clinical course : acute – subacute – chronic

• Risk factors : Alcohol , eldery , antiplatelet , anticoagulant

Signs and symptoms• Loss of

consciousness or fluctuating levels of consciousness

• Disorientation• Irritability• Seizures• Headache (either

constant or fluctuating)

• Numbness

• Amnesia• Weakness• Personal change• Ataxia• Gait disturbance• Urinary incontinence• Nausea and

vomiting• Blurred vision• Dizziness

Acute SDH

Subcute SDH

Chronic SDH

Chronic SDH

Subarachnoid hemorrhage (SAH)

• Bleeding between arachnoid and pia mater

• Causes : spontaneous (rupture aneurysm ) , trauma

• Clinical – Thunderclap headache–Vomiting–Confusion– Seizure–Coma

Intracerebral hemorrhage (ICH)

• Cause – Trauma–Nontrauma • HT hemorrhage ( thalamus, basal ganglion, pons, cerebellum)• AVM rupture• Bleeding tumor

• Clinical : location

Thalamic hemorrhage with intraventricular hemorrhage and hydrocephalus

Cerebellar hemorrhage with intraventricular hemorrhage

Normal pressure hydrocephalus

• Adams triad or Hakim's triad –Gait instability–Dementia–Urinary incontinence

• DDx– PD–AD–Vascular dementia

Cerebral infarction

Sudden onset of• Weakness ( facial weakness , limbs

weakness , dysarthria)• Aphasia• Numbness• Ataxia• Alteration of consciousness• Visual disturbance (blindness , visual

field defect, double visions)

Circle of Willis

Arterial supply of brain

• Acute cerebral infarctions often cannot be seen by CT scanning in the first 6 to 12 hours

• Cell death and edema lead to an area of hypodensity seen in the distribution of the artery

• Persistent areas of hypodensity in the brain tissue resulted of gliosis and of brain necrosis with replacement by CSF

Middle cerebral artery(MCA)syndrome

• Hemiparesis/Hemiplegia or arm weakness

• Hemianesthesia• Aphasia in dominant hemisphere(Motor,

sensory, conductive, transcortical ,or global aphasia)

• Neglect , anosognosia or apraxia in nondominant hemisphere

• Homonymous hemianopia

Middle cerebral artery infarction

Anterior cerebral artery(ACA)syndrome

• Hemiparesis/Hemiplegia primarily leg• Henianesthesia primarily leg• Apraxia, disconnection syndrome• Urinary incontinence

Anterior cerebral artery infarction

Posterior cerebral artery(PCA)syndrome

• Homonymous hemianopia• Cortical blindness• Hemianesthesia or dysesthesia

(thalamic pain)• Visual agnosia, prosopagnosia• Memory deficit

Posterior cerebral artery infarction

Vertebro basilar system syndrome

• Hemiparesis or quadriparesis• Cranial nerve abnormality• Hemiparesis or total anesthesia• Vertigo, nausea, and vomiting, along

with nystagmus• Ataxia or dysmetria• Horner’s syndrome

Brainstem infarction

Magnetic resonance imaging (MRI)

• Atomic nuclei (person) placed in a static magnetic field and then probed with a pulse of magnetic energy

• Hydrogen (protons) is the most abundant element in biological tissue

• The intensity of MRI signals determine the proton density and relaxation time

T1-weight

T2-weight

fluid attenuation inversion recovery (FLAIR)

DWI (diffusion weighted imaging )

• Measure the diffusion of water protons in brain tissue

• Sensitive in acute ischemic stroke within 30 minutes

• Bright on DWI ( restricted on DWI)

Acute Left parieto-occipital infarction

MRI in patient with dementia

• Alzheimer’s disease• Frontotemporal lobe dementia• Normal pressure hydrocephalus• Vascular dementia• Dementia with Lewy bodies

MRI finding in dementia

Alzheimer’s disease

Normal Elephant sign in AD

Alzheimer’s disease

CT brain

Frontotemporal lobe dementia

Normal pressure hydrocephalus

T2 weight FLAIR

• Large vessel infarctions–Bilateral in the ACA territory – Parietotemporal- and temporo-occipital

association areas of the dominant hemisphere (angular gyrus included)

– Posterior cerebral artery territory infarction of the paramedian thalamic region and inferior medial temporal lobe of the dominant hemisphere

Vascular dementia

• Watershed infarctions in the dominant hemisphere (superior frontal and parietal)

• Small vessel disease–Multiple lacunar infactions in frontal

white matter (>2) and basal ganglia (>2)

–WMLs (at least more than 25% of WM)– Bilateral thalamic lesions

Vascular dementia

Vascular dementia

PCA infarction involving medial temporal lobe

Vascular dementia

MRI in parkinsonism

• Multiple system atrophy• Progressive supranuclear palsy• Wilson’s disease• Huntington’s disease

Progressive supranuclear palsy(PSP)

‘Humming bird sign' due to midbrain atrophy

Humming bird sign and Mickey mouse sign in PSP

Normal

Multiple System Atrophy(MSA)

Wilson’s disease

Midbrain : Face of Giant panda sign

Wilson’s disease

Pons :face of the miniature panda

Huntington’s disease

Caudate atrophy

White matter lesion in NPSLE