BRAIN & SKULL CT SCAN

DONE BY:Haya Al-ThuwainiAliah Al-Qahtani

Khuloud Al-Washmi Prepared for:

Dr. Al-Rammah

Computed tomographyA cranial computed tomography (CT) scan is an imaging method that uses x-rays to create cross-sectional pictures of the head, including the skull, brain and facial bone.

Contraindication of CT: Pregnancy except in rare cases such as post trauma. Contrast allergy

Contraindication of contrast media:Hemorrhage to avoid increasing the area of Hemorrhage.

Head CT scan procedures:

A. Trauma CT scan.B. Routine CT scan:1) Plain (c-).2) Routine with contrast (c+).3) 2D \ 3D.

Trauma CT scan:Indication:

Adult hydrocephalus , headache – stroke.Acute infarction (CVA).Hemorrhage trauma.

Patient preparation:Commonly non.If the patient is not stable , stabilize the patient and sedation as need.

Patient position:

Supine with head first in gantry.Vertical center: on the mid of the head.Horizontal line: on the orbital line.

Important planes:Saggital lineOptical meatus lineOrbital line.

Technique:

Start with the patient data registration.lateral scout film (90 degree).

Scan type Start location

End location

KV mA Scan plane

Voice light timer

Scout S 200 I 100 80 10 90 degree No need

From the scout film, select the start and end location.

Start location: gantry tilt line parallel with the canthromeatal around 22 degree.

End location: end of the skull use the lateral topogram (scout).

Gantry tilt parallel with optical meatus line, to avoid eyes exposure & to show the anatomy & small lesions within brain fossa (anterior, mid & posterior).

Axial scan:

Thickness of slice x spacing = 5x5 mm continuous scanning

Scan type

KV mA Scan delayed

Sec Slice Res FOV algorithm No of image

axial 120 300 no 2 5 2.5 20cm Standardbone

28

Types of image windowingwindow purpose WL WW

STANDARD Soft tissue pathology 40 80

BONE structure, fracture 300 1500

Reconstruction types: STANDARD.

BONE.

Routine CT scan:1- Plain (C-)

Indication:

enlarged brain cavities (ventricles) in patients with hydrocephalus.

VP shunt ( drainage of fluids from dilated ventricles in case of

hydrocephalus to role out obstruction of VP tube).

Headache.

Brain lesion or tumor.

Epilepsy.

Vertigo.

Dizziness.

Preparation:1) NPO 3-4 hrs.

2) Patient not allergic, not asthmatic.

3) Renal function test. Diabetic patients not more than 3 months before the examination.

Non diabetic 6 months.

In patient one week.

4) Pregnancy test for married female.

5) Sedation for pediatric patient as needed (≤ 12 years).

Procedure:Same as trauma scan.

2- Routine with contrast (C+)

Indication:• Metastasis: include the brain and whole body scan.• Brain tumor.

Preparation:• Same as before.

Technique:Repeat the same series done for plain, then injects the CM.

Types of CM:Omnipaque or xenetix.

Amount:Adult (≥13 YEARS) 50cc IV.Pediatric weight x 2.

3- 2D &3D

Indication:Microcephalic: small head.Craniostenosis: enlarged head.Skull fracture.

Technique:Same as plain but with different technique parameter. Slice thickness x spacing = 5 x 2.5mm overlap scanning (not missing any lesion).

Different between 3D and routine scanning:

3D Routine

Types of scan helical axial

Effect of brain tissue bone structures Soft tissue

Scan time faster slower

thickness 5 x 2.5 mm 5 x 5 mm

Therapeutic rule of brain CTInfusion (perfusion):Aim:

earlier diagnosis for infarction (no need to waits 72 hrs after the start of weakness).Increase the blood supply to the affected area.

No. of images: at least 500 image.

Technique: Brain plain: to localize the area of interest.Inject the CM with the automatic injector. Cover 8 cm of interested area.

Advantage:Earlier diagnosis gives effective treatment.

Disadvantages:High radiation dose ( = 40 chest x-ray).

After care:Ask the patient to drink a lot of fluids.

Complication: none.

Immobilization devices:Axial holder.

Reference:KKUH

THANKYOU..