brain & skull ct scan
Post on 22-Feb-2016
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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..
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