N's

Question 1

negative contrast agent

Answer 1

A contrast medium that absorbs very few x-rays and is less opaque than soft tissue or fat (i.e., a gas such as room air, carbon dioxide, nitrous oxide, or oxygen).

Question 2

nephrogram

Answer 2

The phase in excretory urography during which the kidneys are opacified by positive contrast medium.

Question 3

niche

Answer 3

A recess in the wall of a hollow organ that retains contrast. Ulcers and diverticuli are examples.

Question 4

nodular lesion

Answer 4

A spherical lesion measuring up to 30 mm in diameter.

Question 5

nodular pulmonary pattern

Answer 5

One or more small, rounded lesions in the lung (i.e., a structured interstitial pulmonary pattern).

Question 6

nonionic iodinated contrast media

Answer 6

Positive contrast agents that are water soluble but not converted into ions, similar in osmolality to plasma, and cause fewer adverse reactions compared with ionic contrast media.

Question 7

nonunion fracture

Answer 7

Fracture healing ceases before a complete union has occurred.

Question 8

Norberg angle

Answer 8

A numerical assessment of coxofemoral joint subluxation made on an extended ventrodorsal pelvic radiograph. Measurement is made by drawing a line connecting the centers of the two femoral heads and another line extending from the center of each femoral head to the cranial edge of the corresponding acetabular rim. Norberg angle greater than 105 is normal, between 90 and 105 is borderline, and less than 90 is abnormal.