Subarachnoid Hemorrhage (SAH) — CT Brain (Non-contrast)

Core radiological features (concise):

1) Hyperdensity in subarachnoid spaces

• Acute blood appears hyperdense (bright)
• Typical locations:
  • Basal cisterns (suprasellar, interpeduncular, ambient)
  • Sylvian fissures
  • Interhemispheric fissure
  • Cortical sulci

2) “Star sign” (basal cistern pattern)

• Star-shaped hyperdensity in basal cisterns around Circle of Willis
• Classic for aneurysmal SAH

3) Sulcal effacement with hyperdense sulci

• Blood outlines sulci → prominent hyperdense cortical sulci
• May coexist with early cerebral edema → sulcal effacement

4) Intraventricular extension (common)

• Hyperdensity within ventricles (especially occipital horns)
• May show fluid–fluid levels

5) Hydrocephalus

• Acute obstructive or communicating hydrocephalus
• Findings:
  • Ventricular dilatation
  • Periventricular lucency (transependymal CSF seepage)

6) Loss of gray–white differentiation (severe cases)

• Due to global cerebral edema (esp. massive SAH)

7) Distribution clues to etiology

• Aneurysmal SAH → basal cistern dominant
• Traumatic SAH → cortical sulci over convexities
• Perimesencephalic SAH → localized around midbrain, limited spread

One-line mnemonic

“Bright blood in cisterns, sulci, fissures ± ventricles + hydrocephalus”

Subdural Hematoma (SDH) — CT Brain (Non-contrast) Key Features

 

Subdural Hematoma (SDH) — CT Brain (Non-contrast) Key Features

Typical Appearance

1. Shape & Location

• Crescent-shaped (concavo-convex) extra-axial collection
• Lies between dura and arachnoid
• Crosses sutures, but does NOT cross midline (limited by falx/tentorium)

2. Density (depends on age)

• Acute (0–3 days): Hyperdense (bright)
• Subacute (3–21 days): Isodense → may be subtle (“CT occult”)
• Chronic (>3 weeks): Hypodense (dark)
• Mixed density: Rebleed → fluid-fluid levels / layering

3. Mass Effect

• Sulcal effacement
• Midline shift
• Compression of ventricles
• Possible subfalcine / transtentorial herniation

4. Internal Characteristics

• Homogeneous (acute) or heterogeneous (chronic/rebleed)
• May show septations/membranes (chronic SDH)

5. Associated Findings

• Underlying cerebral edema
• Cortical contusions
• Skull fracture less common than in EDH

High-yield Differentiation (SDH vs EDH)

• SDH: Crescentic, crosses sutures
• EDH: Biconvex (lens-shaped), does NOT cross sutures

Rapid Mnemonic

“SDH = Sickle, Spreads, Slowly changes density”

• Sickle (crescent)
• Spreads across sutures
• Slow evolution → density changes

Normal CT Brain (Non-contrast) — Key Radiological Features (Concise)

 

1. Symmetry

• Bilateral cerebral hemispheres symmetrical
• No midline shift
• Falx cerebri in midline

2. Grey–White Matter Differentiation

• Clear distinction:
  • Grey matter (cortex, basal ganglia) → slightly hyperdense
  • White matter → slightly hypodense
• Preserved corticomedullary junction

3. Ventricular System

• Lateral, 3rd, 4th ventricles:
  • Normal size and configuration
  • Symmetrical
• No dilatation or compression

4. Cisterns & Sulci

• Basal cisterns (suprasellar, ambient, quadrigeminal) → open and well-defined
• Cortical sulci:
  • Normal for age
  • No effacement (→ edema) or prominence (→ atrophy)

5. Basal Ganglia & Thalami

• Normal density and symmetry
• No focal hypo/hyperdense lesions

6. Brainstem & Cerebellum

• Normal size, contour, and density
• No focal lesion or compression

7. No Abnormal Densities

• No:
  • Hyperdensity → hemorrhage
  • Hypodensity → infarct/edema
• No calcification (except physiological: pineal, choroid plexus)

8. Midline Structures

• Falx, septum pellucidum → central
• No mass effect or shift

9. Bone & Extra-axial Structures

• Skull vault intact (no fracture)
• No:
  • Extradural/subdural collection
  • Scalp swelling

10. Orbits & Sinuses (Screening)

• Orbits normal
• Paranasal sinuses:
  • Air-filled (no fluid level or opacification)

Ultra-short Mnemonic: “S G V C B B M B O”

• Symmetry
• Grey–white differentiation
• Ventricles
• Cisterns/sulci
• Basal ganglia
• Brainstem/cerebellum
• Midline
• Bones/extra-axial
• Orbits/sinuses

Epidural Hematoma (EDH) — CT Brain (Non-contrast)

Core CT Features (Acute EDH)

• Shape: Biconvex / lentiform (lens-shaped)
• Density: Homogeneous hyperdense (acute blood)
• Location: Extra-axial, between skull and dura
• Suture relation: Does NOT cross sutures (tight dural attachment)
  (may cross dural reflections rarely if large)
• Midline shift / mass effect: Common → sulcal effacement, ventricular compression
• Underlying skull fracture: Frequently present (esp. temporal bone)

Additional Signs

• “Swirl sign” → hypodense areas within hematoma (active bleeding)
• Lucid interval correlation (clinical, not CT but supportive)
• Effacement of cisterns if severe

Evolution

• Acute (0–3 days): Hyperdense
• Subacute: Isodense → may be missed without contrast
• Chronic (rare for EDH): Hypodense

Key Differentiation (vs SDH)

• EDH → Biconvex, limited by sutures
• SDH → Crescentic, crosses sutures but not midline (falx limit)

Rapid Mnemonic

“EDH = Egg-shaped, Does NOT cross sutures, High density”

 

Spine Fracture — Knowledge Stratification

🔹 Intern Level

Core Concepts

• Definition: Disruption of vertebral body ± posterior elements due to trauma
• Common causes:
  • RTA (most common)
  • Fall from height
  • Osteoporotic collapse (elderly)

Basic Classification (Recognition level)

• Compression fracture
• Burst fracture
• Fracture-dislocation (unstable)

Clinical Red Flags

• Back pain + trauma
• Neurological deficit (weakness, numbness)
• Bladder/bowel involvement → emergency

Initial Management (ATLS mindset)

• Immobilize spine (cervical collar, log roll)
• ABC stabilization
• Avoid unnecessary movement

Basic Imaging

• X-ray: screening
• CT: confirm fracture
• MRI: neurological deficit / ligament injury

🔹 MBBS Doctor Level

Detailed Classification Awareness

• Stable vs unstable fracture
• Denis 3-column theory:
  • Anterior column
  • Middle column
  • Posterior column
• Instability if ≥2 columns involved

Common Injury Patterns

• Compression → anterior column
• Burst → anterior + middle (retropulsion risk)
• Chance fracture → flexion-distraction
• Fracture-dislocation → all 3 columns (highly unstable)

Neurological Correlation

• Cervical → quadriplegia
• Thoracic → paraplegia
• Lumbar → cauda equina syndrome

Indications for Urgent Referral

• Neurological deficit
• Suspected unstable fracture
• Severe pain with deformity

Basic Management Principles

• Analgesia
• Immobilization (brace/collar)
• Early referral to spine/neurosurgery

🔹 Other Discipline Resident Level (Orthopedic/Medicine/EM)

Advanced Classification Systems

• AO Spine Classification:
  • Type A: Compression
  • Type B: Tension band injury
  • Type C: Translation/rotation

Stability Assessment

• Mechanical instability
• Neurological instability
• Ligamentous injury (MRI importance)

Radiological Interpretation

• CT: gold standard for bony injury
• MRI:
  • Cord edema/contusion
  • Posterior ligament complex (PLC) injury

Management Decision Basics

• Conservative:
  • Stable fractures
  • No neuro deficit
• Surgical:
  • Unstable fracture
  • Neuro deficit
  • Progressive deformity

Complications

• Neurological deterioration
• Kyphotic deformity
• Chronic pain

🔹 Junior Neurosurgery Resident Level

Comprehensive Classification & Scoring

• AO Spine system (detailed)
• TLICS (Thoracolumbar Injury Classification Score):
  • Morphology
  • PLC integrity
  • Neurology
  • Score ≥5 → surgery

Biomechanics & Injury Mechanism

• Axial load → burst fracture
• Flexion → compression
• Flexion-distraction → Chance fracture
• Rotation → fracture-dislocation

Radiological Nuances

• CT:
  • Canal compromise (%)
  • Pedicle involvement
• MRI:
  • PLC disruption (key surgical indicator)
  • Cord signal change (prognostic)

Surgical Indications

• Neurological deficit with compression
• Unstable fracture (AO B/C, TLICS ≥5)
• Significant canal compromise
• Progressive deformity / kyphosis

Surgical Options

• Posterior fixation (pedicle screw)
• Anterior decompression (corpectomy)
• Combined approach (severe instability)

Emergency Management

• High-dose steroids (controversial; selective use)
• Early decompression (<24 hrs preferred in SCI)

Postoperative Considerations

• DVT prophylaxis
• Early mobilization
• Rehabilitation

Complications to Anticipate

• Hardware failure
• Non-union
• Post-traumatic kyphosis
• Neuro deterioration

🔑 High-Yield Summary

• Instability = key decision point
• CT → bone, MRI → cord + ligaments
• TLICS ≥5 → surgery
• Neuro deficit = urgent decompression
• Always immobilize first, diagnose later

Gynae & Obs SBA Questions contain single best answer or MCQ question for MRCS, FCPS part-1 examination.

“Gynae & Obs SBA Questions”

Gynae & Obs SBA Questions contain single best answer or MCQ question for MRCS, FCPS part-1 examination.

This app is based on the SBA (Single best answer) question of Gynae & Obs of FCPS part-1 examination held in Bangladesh (two times in every year) and Pakistan. It also helpful for MRCS exam, USMLE exam, Residency exam in all over the world especially India.  Every year thousands of students take part in this exam but they do not have enough confidence to answer this SBA, as SBA question is rarely available to practice. 

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