COMPUTED TOMOGRAPHY LESSON 8
supine, lateral topogram scan excursion is plotted from arcuate eminence (the summit of the temporal bone) through the mastoid tip. Collimation collimator of 0.6 mm to at least 1 mm. 1 mL/lb to a maximum of 80 to 100 infections such as coalescent mastoiditis or for the evaluation of abscesses.
TEMPORAL CT PROTOCOLS
ethmoid sinus tumor who also has an opacified frontal sinus.
CT and MRI are complementary, such as with a patient with an
CTDIvol x scan length
DLP (mGy*cm)
helical scanning state-of-the-art). It is used for evaluation and management of neuro-ophthalmic and orbital diseases, especially for trauma, proptosis, and childhood leukocoria.
ORBITS CT PROTOCOLS
Evaluation for sinusitis.
Supine (table top, Spiral. 0.75-mm collimator. Frontal sinuses through hard palate (Scan Craniocaudal).
PARANASAL SINUS WITH CONTRAST CT PROTOCOLS for tumors, masses,
Supine. Hard palate through frontal sinuses. Spiral. Collimator: 0.75. 75 cc bolus.
convolution algorithm
The kernel, also known as a ___, refers to the process used to modify the frequency contents of projection data This process corrects the image by reducing blurring.
CTDIw (mGy)
closer to the human dose profile 2/3 CTDI100 (periphery) + 1/3 CTDI100 (center)
(MRI)
evaluation of cranial nerve palsies and optic nerve lesions, especially if intracranial extension is suspected. Evaluating for intralesional calcium and the effects on adjacent bone
dose-length product (DLP)
factors in the length of the scan to show overall dose output
(standard kernel)
kernels including soft tissue
CTDI100 (mGy)
linear measure of dose over a pencil ionization does not take into consideration the topographical variation of a human body
CT dose index (CTDI)
mGy) is standardized measure of radiation dose output
CTDIvol (mGy)
obtained by dividing CTDIw by pitch factor.
(bone kernel).
produce a sharper image with higher spatial resolution.
CTDIvol
the parameter ___ is the more commonly used index.
Computed tomography
to show many of the lesions remains a quick, clinically effective, and cost-effective method for evaluating most orbital problems.
CTDI100 CTDIw
were used; for helical scanners