imaging procedures Flashcards
during axial scanning
spatial resolution?
scan time ?
patient dose?
increased spatial resolution
increased scan time
increased patient dose
helical scanning
spatial resolution?
scan time ?
patient dose?
decreased spatial resolution
decreased scan time
decreased patient dose
What does volume mean in CT
entire area acquired with one tube rotation
Thin slices =
_______ noise and ______ resolution
high noise and high resolution
thick slices =
________ noise and ______ resolution
low noise and low resolution
slice interval
interval = thickness
interval > thickness
interval < thickness
slices start where another stops
gaps between slices
overlapping slices
contrast volume for pedi patients
1mL per lb
what happens during a contrast injection using timing bolus?
small bolus of contrast is injected into the patient and monitored. post test, the tech will look at images and pick the highest contrast enhancement time. the scan will be preformed at that injection time
Initial evaluation of stroke, headache, vertigo, and seizures are an indication for which type of scan?
ct head wo
CT head wo:
scan type-
slice parameters-
gantry tilt-
contrast-
algorithm-
scan type- axial preferred
slice parameters- 2.5 thick in posterior fossa and 5.0mm thick through vertex
gantry tilt- parallel to OML
contrast- wo for trauma or stroke. with for tumors or infection
algorithm- standard (80 ww and 30 wl) and bone (2500 ww and 600 wl)
CT facial bones
scan type-
slice parameters-
gantry tilt-
contrast-
algorithm-
scan type- helical
slice parameters- 1.25mm
gantry tilt- parallel to hard palate
contrast- wo for fracture or trauma and with for mass swelling, abscess) 45 seconds post injection
algorithm- standard (400 ww and 40 wl) bone (2500 ww and 600 wl)
facial trauma, mass, swelling, infection, and dental abscess indicates which type of scan?
CT facial bones
Proptosis (budging in the eye), pain, vision changes, abnormalities are indications of which type of scan?
CT orbits
CT orbits
scan type-
slice parameters-
gantry tilt-
contrast-
algorithm-
scan type- helical
slice parameters- 1.5 higher spatial resolution
gantry tilt- parallel to hard palate
contrast- wo for trauma or fracture. with for mass or swelling 60 seconds post injection
algorithm- standard (400 ww and 40 wl) bone (3500 ww and 600 wl)
survey of sinuses, sinusitis, sinus pain indicates which type of scan?
CT sinuses
CT sinuses
scan type-
slice parameters-
gantry tilt-
contrast-
algorithm-
scan type- helical
slice parameters- 3.75mm
gantry tilt- direct coronals perpendicular to hard palate (pt prone with head up for air fluid levels)
contrast- none
algorithm- bone (2500ww and 600 wl)
pain, ataxia (loss of coordination), and hearing loss are indications for which type of scan?
CT temporal bone
CT temporal bone
scan type-
slice parameters-
gantry tilt-
contrast-
algorithm-
scan type- helical
slice parameters- .625 thickness and .315 interval with overlapping slices
gantry tilt- direct coronals with pt prone and head up
contrast- none
algorithm- bone (2500ww and 600wl)
Vascular abnormalities, aneurysm, AV malformation, not stroke are indications for which type of scan?
CTA head
CTA head
scan type-
slice parameters-
gantry tilt-
contrast-
algorithm-
scan type- helical and inferior to superior
slice parameters- .625mm
gantry tilt- none
contrast- 100-150mL @ 4 using bolus tracking or timing bolus ROI at aortic arch
algorithm- standard (400 ww and 40 wl)
stroke, aneurysm, and dissection are indications for which type of scan
CTA head and neck