🧠 CT SCAN BRAIN – STEP BY STEP NOTES

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1️⃣ WHAT IS CT SCAN?

CT (Computed Tomography) is an imaging technique that uses X-rays + computer processing to create cross-sectional (slice) images of the body.

👉 In brain CT:

• It shows bone, blood, calcification very clearly
• Fast and life-saving in emergencies ⚡

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2️⃣ WHY DO BRAIN CT SCAN?

📌 Main Indications:

• Head injury / trauma 🚑 
• Stroke (ischemic / hemorrhagic)
• Brain hemorrhage
• Tumor / metastasis
• Hydrocephalus
• Infection (abscess, TB, etc.)
• Seizures / epilepsy
• Post-operative follow-up

👉 Emergency modality of choice (especially for bleeding)

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3️⃣ PATIENT PREPARATION

• Explain procedure to patient
• Remove metal objects (chain, clips, denture)
• Check history (trauma, surgery, symptoms)
• For contrast:
  • Check renal function (Creatinine)
  • Allergy history

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4️⃣ PATIENT POSITIONING

🛏️ Standard Position:

• Patient supine
• Head first entry
• Head placed in head holder

🎯 Alignment:

• Mid-sagittal plane → center
• Orbitomeatal line (OML) → perpendicular to table

👉 Immobilization is important (use head straps)

🧠 CT SCAN BRAIN – STEP BY STEP NOTES

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5️⃣ SCAN PLANNING

📍 Scan Range:

• SCALP TO BASE OF SKULL.
• From foramen magnum → vertex

📐 Planning Line:

• Parallel to OML (Orbitomeatal line)

👉 In trauma:

• Use thin slices + full brain coverage

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6️⃣ SCAN PARAMETERS (Typical)

• kVp → 120
• mAs → 200–300 (depends on machine)
• Slice thickness:
  • 5 mm (routine)
  • 1–2 mm (thin slices / trauma / HRCT brain)
• Pitch → ~0.5–1
• Rotation time → 1 sec

🧠 Windows:

• Brain window → for parenchyma
• Bone window → for skull fracture

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7️⃣ CONTRAST STUDY (If needed)

• IV contrast (Non-ionic iodine)
• Dose: ~1–1.5 ml/kg

Used in:

• Tumors
• Infection
• Vascular lesions

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8️⃣ IMAGE RECONSTRUCTION

• Axial images (primary)
• Coronal & sagittal (MPR)
• Bone & soft tissue algorithm

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9️⃣ FILMING / DISPLAY PROTOCOL

🧾 Routine Films:

• Axial brain window
• Axial bone window
• Coronal & sagittal reformats

🎯 Display:

• Proper windowing
• Label (Name, Age, Date)
• Side marker (R/L)

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🔟 COMMON PATHOLOGY

🧠 1. Hemorrhage

• Hyperdense (white) area
• Types:
  • Epidural
  • Subdural
  • Intracerebral

🧠 2. Infarct (Stroke)

• Hypodense (dark area)
• Loss of gray-white differentiation

🧠 3. Tumor

• Mass effect
• Edema
• Midline shift

🧠 4. Hydrocephalus

• Dilated ventricles

🧠 5. Skull Fracture

• Seen in bone window