NMTCB (CT) - HEAD AND NECK CT
PROCEDURES
Head CT - routine brain - ANSWER-patient
- trauma, suspected atrophy, hydrocephalus, dementia
scan
- contrast = ONLY to evaluate tumors, edema, aneurysms, headaches, seizures
- head first and supine
- transverse slices
- axial = skull base to the vertex
- thin slices = reduce streaking
mA = 300
kVp = 120
reconstruction = retrospective recon, sharp filter
(bony detail)
Head CT - internal auditory canals (IAC) - ANSWER-- directly acquires thin coronal
slices
- thin axial slices
- contrast =
hearing loss, acoustic neuroma, malignant otitis externa
- No contrast =
temporal bones, mastoiditis, cholesteatoma
scan
- posterior fossa to IAC or petrous bone
- coronals should be perpendicular to axials
mA = 200 -400
- recon = standard and sharp filter
- transverse and coronal planes
- thin slices = more detail, increased noise
Head CT - temporomandibular joint (TMJ) - ANSWER-optimal viewing orientation =
oblique sagittal plane
(nearly impossible)
- referred for MRI
, CT scan preferred
- fracture, bony erosion
- no contrast
- transverse helical scan
recon
- multiplanar recon
- standard and sharp filter
mAs= 250
Head CT - angio circle of Willis - ANSWER-- evaluation of intracranial arteries
- CTA = evaluates intracranial aneursyms and vascular occlusion
Intra arterial digital subtraction angiography(CTA)
- gold standard for aneurysms and congenital anomalies
- CNS risk = 0.1 -2.6%
- more advantages over MRA
contrast = 100mL IV is injected at rate 4 -4.5ml/sec
- optimal scanning begins 24 secs after injection
scan
- thin helical slices from C2 through 3/4 of the brain
mAs= 250
kVp= 120
recon
- coronal and sagittal images
- MIP and 3D volume rendering
Head CT - pituitary - ANSWER-contrast = almost always used to enhance normal
pituitary tissue
scan
- axial = roof of sphenoid sinus through the dorsum sella
- coronal = anterior clinoid through the dorsum sella (more detail)
mA = 200 -400
recon = standard and sharp filter
Head CT - orbits - ANSWER-- reduce streaks = pt eyes focused stationary
contrast = suspected mass, visual disturbance, infection
NO contrast = trauma, foreign bodies, graves disease
PROCEDURES
Head CT - routine brain - ANSWER-patient
- trauma, suspected atrophy, hydrocephalus, dementia
scan
- contrast = ONLY to evaluate tumors, edema, aneurysms, headaches, seizures
- head first and supine
- transverse slices
- axial = skull base to the vertex
- thin slices = reduce streaking
mA = 300
kVp = 120
reconstruction = retrospective recon, sharp filter
(bony detail)
Head CT - internal auditory canals (IAC) - ANSWER-- directly acquires thin coronal
slices
- thin axial slices
- contrast =
hearing loss, acoustic neuroma, malignant otitis externa
- No contrast =
temporal bones, mastoiditis, cholesteatoma
scan
- posterior fossa to IAC or petrous bone
- coronals should be perpendicular to axials
mA = 200 -400
- recon = standard and sharp filter
- transverse and coronal planes
- thin slices = more detail, increased noise
Head CT - temporomandibular joint (TMJ) - ANSWER-optimal viewing orientation =
oblique sagittal plane
(nearly impossible)
- referred for MRI
, CT scan preferred
- fracture, bony erosion
- no contrast
- transverse helical scan
recon
- multiplanar recon
- standard and sharp filter
mAs= 250
Head CT - angio circle of Willis - ANSWER-- evaluation of intracranial arteries
- CTA = evaluates intracranial aneursyms and vascular occlusion
Intra arterial digital subtraction angiography(CTA)
- gold standard for aneurysms and congenital anomalies
- CNS risk = 0.1 -2.6%
- more advantages over MRA
contrast = 100mL IV is injected at rate 4 -4.5ml/sec
- optimal scanning begins 24 secs after injection
scan
- thin helical slices from C2 through 3/4 of the brain
mAs= 250
kVp= 120
recon
- coronal and sagittal images
- MIP and 3D volume rendering
Head CT - pituitary - ANSWER-contrast = almost always used to enhance normal
pituitary tissue
scan
- axial = roof of sphenoid sinus through the dorsum sella
- coronal = anterior clinoid through the dorsum sella (more detail)
mA = 200 -400
recon = standard and sharp filter
Head CT - orbits - ANSWER-- reduce streaks = pt eyes focused stationary
contrast = suspected mass, visual disturbance, infection
NO contrast = trauma, foreign bodies, graves disease
