✔✔blood urea nitrogen (BUN) - ✔✔a measurement of renal function, determined as the
amount of nitrogen in the blood in the form of waste product urea. the normal range of
BUN in adults is 7 to 25 mg/dL.
✔✔bow-tie filter - ✔✔a type of filter added to the CT x-ray tube to compensate for the
cylindrical shape of most body parts. the filter is thicker at the ends and helps shape the
beam to reduce patient radiation exposure.
✔✔cardiac cycle - ✔✔the series of blood-flow related events that occur from the
beginning of one heartbeat to that of the next.
✔✔cerebral blood flow (CBF) - ✔✔a common measurement during CT perfusion studies
of the brain. CBF is the quantity of blood (mL) that moves through 100 g of brain tissue
each minute. normal range in gray matter is 50 to 60 mL/100 g/min
✔✔cerebral perfusion - ✔✔the level of blood flow throughout brain tissue.
✔✔constant mAs - ✔✔the product of milliamperage (mA) and scan time (seconds)
utilized for a CT acquisition.
✔✔contiguous images - ✔✔CT images acquired with equal section thickness and
reconstruction intervals
✔✔contrast resolution - ✔✔the ability of a CT system to detect an object with a small
difference in linear attenuation coefficient with the surrounding tissue. may also be
referred to as low-contrast detectability or sensitivity.
✔✔contrast-induced nephrotoxicity (CIN) - ✔✔a substantial decline in renal function that
can occur after a patient receives IV contrast material. it is usually signified by a marked
increase in serum creatinine over a baseline measurement obtained prior to contrast
agent administration.
✔✔convolution - ✔✔mathematical filatration used by the CT system to remove blurring
artifact during the back-projection method of image reconstruction
✔✔corticomedullary phase - ✔✔a late arterial phase of renal enhancement beginning
30 to 40 seconds after the initiation of contrast agent administration. optimal
enhancement of the renal cortex and renal veins occurs during this period.
✔✔creatinine - ✔✔a waste product of metabolism found in the bloodstream and
measured as an indicator of renal function. normal range is 0.5 to 1.5 mg/dL.