mid term revision imaging procedure 3 dr mohamed el safwany, md
TRANSCRIPT
Mid Term Revision
Imaging Procedure 3
Dr Mohamed El Safwany, MD.
GOALS OF CT
• MINIMAL SUPERIMPOSITION
• IMAGE CONTRAST IMPROVEMENT
• SMALL TISSUE DIFFERENCE RECORDING
CT MAIN SYSTEMS
• IMAGING SYSTEM
• COMPUTER SYSTEM
• DISPLAY, RECORDING, STORAGE SYSTEM
• DATA ACQUISITION SYSTEM
COORDINATE SYSTEM IN CT
X
COORDINATE SYSTEM IN CT
Y
COORDINATE SYSTEM IN CT
Z
COORDINATE SYSTEM IN CT
ISO-CENTER
PATIENT ORIENTATION• HEAD FIRST • FEET FIRST
Computed tomography
Soft-tissue
Bone window
Computed tomography
• Unit controls:– Scanogram AP – Gantry tilt 0º– Slice thickness 7mm– Slice gap 9mm– Soft-tissue (Mediastinal)
window– Lung window
Computed tomography
Mediastinal window Lung window
Computed tomography
Computed tomography
• Positioning:– Supine and feet first – Arms above the head– The knees flexed 30º
• Parameters:– Starting at xiphoid process – Ending at the level of hip
joint – Respiration suspended in
expiration
Computed tomography
Unit controls • Gantry tilt: 0º. • Lateral scout view.• Gantry tilt: • parallel to the disc space • Slice thickness:
– 3mm
Computed tomography
air ---1000
fat---70
Pure water 0
Csf+8
White matter+30
Gray matter+45
blood+70
Bone/cacification+1000
MCA INFARCT
ACA INFARCT
Old infarct
H’gic infarct
CSF Production
• Produced in choroid plexus in the lateral ventricles Foramen of Monroe IIIrd Ventricle Acqueduct of Sylvius IVth Ventricle Lushka/Magendie
• 0.5-1 cc/min• Adult CSF volume is approx. 150 cc’s.• Adult CSF production is approx. 500-700 cc’s
per day.
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B is for Blood
• 1st decision: Is blood present?
• 2nd decision: If so, where is it?
• 3rd decision: If so, what effect is it having?
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Subdural Hematoma
• Typically falx or sickle-shaped.• Crosses sutures, but does not
cross midline.• Acute subdural is a marker for
severe head injury. (Mortality approaches 80%)
• Chronic subdural usually slow venous bleed and well tolerated.
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Andrew D. Perron, MD, FACEP
CT ScanCT Scan
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Intraventricular/Intraparenchymal Hemorrhage
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CT ScanCT Scan
Andrew D. Perron, MD, FACEP30
FRONTAL SINUS
CT SINUS AXIAL
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LENS OF EYE
RETRO ORBITALFAT
ETHMOIDSINUS
MEDIAL RECTUS MUSCLE
LATERAL RECTUSMUSCLE
CT SINUS AXIAL
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CT SINUS CORONAL VIEW
MAXILLARY SINUS
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NASAL SEPTUM
ORBIT
AXIAL CT
RETRORBITAL FAT
MEDIAL RECTUS LENS OF EYE LATERAL
RECTUS
OPTIC NERVE
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ARTERIOGRAM CAROTIDSYPHON
OCCIPITALARTERY
INTERNAL CAROTID ARTERY
EXTERNAL CAROTID ARTERY
COMMON CAROTIDARTERY
MAXILLARYARTERY
MIDDLE CEREBRAL
ARTERY
ANTERIOR CEREBRALARTERY
FACIALARTERY
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ANATOMYThe pulmonary arteries carry blood from the heart to the lungs.
They are the only arteries that carry deoxygenated blood.
INDICATION
Pulmonary embolism
Aortic dissection
Aortic overloading
Left ventricular stress
Teratology of Fallot
CONTRAST DOSAGE
1.2ml /kg (body weight) of non-ionic iodinated contrast
medium is injected intravenously into the patient using a
pressure injector.
Rate of injection being 4-5 ml /sec
Pressure 325 ppm
PATIENT POSITIONING
Proper breath hold instructions should be given
Ensure the patient connected IV lines, are long enough to
allow full travel of the couch without being pulled or entangled
while undergoing a CT
It is a software, that allows real-time monitoring of IV
Contrast enhancement in the area of interest.
SMART PREP TECHNIQUE
Good Luck