GEMC: Systematic Evaluation to Non-Traumatic Head CTs: Resident Training

Project: Ghana Emergency Medicine Collaborative Document Title: Systematic Evaluation to Non-Traumatic Head CTs Author(s) Rashmi U. Kothari, MD (KCMS/MSU), 2012 License: Unless otherwise noted, this material is made available under the terms of the Creative Commons Attribution Share Alike-3.0 License: http://creativecommons.org/licenses/by-sa/3.0/

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Systematic Evaluation to Non-Traumatic Head CTs

Rashmi U. Kothari, MD KCMS/MSU

Source Undetermined

Why do you need to be able to evaluate a CT

Ø Radiology report is not immediately available

Ø Need immediate intervention

Ø Don’t trust anyone

Course Outline

Ø Basic principles of CT

Ø Basic anatomy

Ø Systematic approach

Ø CT Potpourri

Course Goals

Ø Learn “Blood Can Be Very Bad” approach to reading CTs

Ø  Identify classic CT findings

Disclaimer

Ø Make you a neuroradiologist

Ø Teach you cause of finding of abnormality

Ø Help you with contrast CTs

Basic Principles of CT Imaging Source Undetermined

X-rays Absorbed Differently by Different Tissues

Radiodense

Calcium

Grey matter

Radiolucent

Spinal fluid

Ischemic infarct

White matter

Source Undetermined

Attenuation (amount of radiation blocked by tissue)

Air Blood Bone

-1000 HU +1000 HU

HU=Hounsfield Units

50-100 HU

Windowing

Ø Blood

Brain Blood

Bone Source Undetermined

Source Undetermined

CT Anatomy

Ø Six levels of cuts Ø  Cortical sulci Ø  Lateral Ventricles Ø  Basal Ganglia Ø  3rd Ventricle Ø  Midbrain Ø  Pons

Source Undetermined

CT Anatomy: Cortical Sulci & Lat. Ventricle

Falx Cortical sulci

Frontal lobe Parietal lobe Lateral ventricles Occipital lobe

Source Undetermined

CT Anatomy: Basal Ganglia & 3rd Ventricle

Anterior horns Insular ribbon Sylvian fissure 3rd ventricle Quadrigeminal cistern

Anterior horns Choroid plexus .

Source Undetermined

CT Anatomy: Midbrain & Pons

Frontal sinus Suprastellar cistern Pons 4th ventrical

Sylvian fissure Insular ribbon Ambient cistern (cirummesenphalic cistern)

Source Undetermined

Systematic Approach to Head CTs

Ø Perron et al: Carolina’s Medical Center

Ø “Blood Can Be Very Bad” pnemonic

Ø Course reviewing 12 scans & short histories

Ø Pre-test 60% to Post-test 78%

Ø http://www.uic.edu/com/ferne/pdf/acep_2005 _peds/perron_ich _acep_2005_peds_ course.pdf

“Blood Can Be Very Bad”

Ø Blood

Ø Cisterns

Ø Brain

Ø Ventricles

Ø Bone Perron et al: Ann Emerg Med 1998:32:554-562

Ø Acute blood = hyperdense (white)

Ø 50-100 HU

Ø As it ages it becomes hypodense

Ø At 1-2 weeks it is isodense with brain

Source Undetermined

Ø 4 cisterns: Ø  Suprasellar Ø  Quadrigeminal Ø  Slyvian Ø  Ambient

Source Undetermined

Andrew D. Perron, MD, FACEP

Cisterns: Is there blood?

Are they open? Source Undetermined

Source Undetermined

Brain Source Undetermined

Source Undetermined

Ventricle

Source Undetermined

Bone Source Undetermined Source Undetermined

Classic CT Findings Source Undetermined

Source Undetermined

Subdural •  Concave shape •  Venous bleeds •  Crosses suture line

Epidural •  Lens shape •  85% arterial bleeds •  Middle meningeal art • Lucid period

Source Undetermined

Intracerebral Hemorrhage

q 10% of all strokes q 2 major causes

q Hypertension q  Blacks & Asians q  50% basal ganglia q  Pons q  Cerebellum

q Amyloid q  Caucasians q  Lobar q  Recurrent

Source Undetermined

Subarachnoid Hemorrhage

q 5-10% of all strokes q Aneurysms, AVMs,

trauma q Hyperdense, fuzzy q Locations of blood

– Sulci – Sylvian fissure – Circle of Willis – Falx – Tentorium

Source Undetermined

ICH Normal ICH

SAH SAH SAH

Source Undetermined Source Undetermined Source Undetermined

Findings Suggestive of ICH

Ø Normal Calcification Ø Basal ganglia Ø Choroid plexus Ø Pineal gland

Source Undetermined

Ø Metal Ø Very hypodense Ø “Sparks” Ø Clips, bullets,

metallic catheters

Source Undetermined

Volume Averaging (Technical Issues Mimicking ICH)

Ø Orbital roof Ø Petrous portion of

temporal bone Ø Pituitary fossa Ø Brainstem

Findings Suggestive of ICH/SAH

Source Undetermined

Motion Artifact (Technical Issues Mimicking ICH or SAH)

Ø Streaky Ø Hyperdense Ø Boney prominence

Source Undetermined Source Undetermined

Evolution of an Infarct

Ultra-Acute 0-3 hours

Acute-Subacute 6hrs-days

Chronic 1 year

Ultra-Early CT Findings

Ø Normal Ø Sulcal effacement Ø Loss of insular ribbon Ø Loss of grey-white

interface Ø Acute hypodensity

Source Undetermined

Sulcal Effacement

Loss of Insular Ribbon

Source Undetermined

Loss of Sulci & Acute Hypodensity

Source Undetermined

Acute Hypodensity

Acute-Subacute Stroke (hours-days)

Ø Hypodense Ø Well demarcated Ø Mass effect Ø Midline shift Ø Loss of sulci

Source Undetermined

Old Infarct (months to years)

Ø Density of CSF Ø Well demarcated Ø Ventrical enlargement Ø Sulci enlargement Ø No sulcal effacement Ø No mass effect

Source Undetermined

Suggestive of an Infarct?

Source Undetermined

Suggestive of an Infarct?

Tumor Stroke Source Undetermined Source Undetermined

Case Presentations

Thalamic ICH

Source Undetermined

Normal

Source Undetermined

Chronic Frontal Subdural

Source Undetermined

Subacute Right Parietal Infarct

Source Undetermined

continued Source Undetermined

SAH Normal

Acute Subdural

Source Undetermined

Normal

Source Undetermined

Closed Ventricles

Source Undetermined

Cisterns: Are they open?

Metallic Artifact

Source Undetermined

Brainstem SAH

Source Undetermined

Chronic MCA Infarct

Source Undetermined

Left IVH

Source Undetermined

Epidural

Source Undetermined

Rt Subacute Epidural

Source Undetermined

Sagital Sinus

Source Undetermined

Subacute Infarct

Source Undetermined

Renal Cell Metastasis

Source Undetermined

SAH Normal

48 hr old Right Temporal Infarct

Source Undetermined

Acute on Chronic Subdural

Source Undetermined

SAH Source Undetermined Source Undetermined

Rt Parietal Fx with Air

Source Undetermined

Brain Abscess

Source Undetermined

Calcification Basal Ganglia

Source Undetermined

hours 3-4 days

7-10 days

months

Trauma with Air

Source Undetermined

Dense MCA Sign

Source Undetermined

Subacute Brainstem Infarct

Source Undetermined

Atrophy

Source Undetermined

Trauma with SAH

Source Undetermined

Bitemporal Edema (Herpes)

Source Undetermined

Meningioma

Source Undetermined

Caudate Infarct

Source Undetermined

IVH Left Lateral Horn

Source Undetermined

Ultra-Early Right Parietal Infarct Right Sulcal Effacement

Source Undetermined

Continued Source Undetermined

Source Undetermined

Subacute Infarct (Rt Temporal Lobe)

Periventricular White Matter Disease

Chronic Rt Occipital Infarct

Source Undetermined

Subacute Subdural

Source Undetermined

Traumatic Petechae

Source Undetermined

Loss of Sulci & Sylvian Fissure

Source Undetermined

Old Lt Lacunar Infarct

Source Undetermined

Subacute Lt Subdural

Source Undetermined

Rt MCA Infarct with Hemorrhage

Source Undetermined

Lt Sagital Vein Thrombosis

Source Undetermined

SAH with Blood along Falx & in Ventricle

Source Undetermined

CT Ground Rule

Radiodense

Calcium

Grey matter

Radiolucent

Spinal fluid

Ischemic infarct

White matter

Source Undetermined

Ø Blood

Ø Cisterns

Ø Brain

Ø Ventricles

Ø Bone Perron et al: Ann Emerg Med 1998:32:554-562

Intracerebral Hemorrhage

q Appearance q Hyperdense q Well demarcated q Globular

q Location q Intraparenchymal

q Mimics q Normal Calcification

q  Basal ganglia q  Choroid plexus q  Pineal gland

q Artifacts q  Metal q  Catheters q  Volume Averaging q  Motion

Source Undetermined

Subarachnoid Hemorrhage q  Appearance

q  Hyperdense q  Fuzzy

q  Locations of blood q  Sulci q  Sylvian fissure q  Circle of Willis q  Falx q  Tentorium

q  Mimics q  Contrast q  Calcified Falx q  Normal Tentorium q  Motion artifact

Source Undetermined

Ultra-Early Infarct Normal

Sulcal effacement

Loss of insular ribbon

Loss of grey-white interface

Acute hypodensity

Acute-Subacute

Hypodense

Well demarcated

Mass effect

Midline shift

Loss of sulci

Old Infarcts

Density of CSF

Well demarcated

Ventrical enlargement

Sulci enlargement

No sulcal effacement

No mass effect

Source Undetermined

GEMC: Systematic Evaluation to Non-Traumatic Head CTs: Resident Training

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