Deck 23: Contrast Media and Introduction to Radiopharmaceuticals

Question 1

The ideal iodinated contrast agent would have what characteristic(s)?
1)High osmolality
2)Low osmolality
3)Nonionic chemical structure
4)Water solubility (hydrophilic)
5)Three or more iodine atoms per molecule

A)1,4,and 5 only
B)1,3,and 5 only
C)2,3,4,and 5 only
D)2 only

Answer 1

C
Efforts to decrease the many side effects of ionic iodine contrast media resulted in the development of molecules that do not dissociate into anions and cations.These are considered nonionics and are less toxic to cells.Additionally,the contrast agent should possess low osmolality so as not to disrupt the fluid environment in which cells exist and to maximize the photoelectric effect.Atomically,a three-iodinated benzene ring maximizes the radiopacity of the molecule,thereby increasing image contrast.

Question 2

For select examinations,air (negative contrast)and radiopaque contrast are used as a pair to outline mucosal linings,joint interspaces,and passageways.These examinations are considered

A)double-contrast studies.
B)extremely dangerous and rarely done.
C)single-contrast examinations.
D)low-contrast studies.

Answer 2

A
For some contrast examinations,negative and positive agents are used together so that the lumen of organs can be visualized or so that anatomic structures within a space,such as the menisci of the knee,can be visualized.Because the contrasts agents are both negative and positive,it is considered a double-contrast study.

Question 3

Laboratory tests to assess a patient's BUN and creatinine are used to determine the patient's

A)liver function.
B)renal function.
C)pancreas.
D)thymus.

Answer 3

B
Increased blood urea nitrogen (BUN)and creatinine (waste product of metabolism)levels indicate that the patient may have renal disease and are good indicators for possible contrast medium-induced renal effects.

Question 4

A common contrast agent used for MRI examinations is

A)ultrasonic microbubbles.
B)barium sulfate.
C)gadolinium-DTPA.
D)triiodinated thorium.

Question 5

Positive contrast agents

A)have high atomic numbers.
B)appear white on radiographs because of the degree of attenuation.
C)have a tendency to absorb x-ray photon energy to a great extent.
D)All of the above are correct.

Question 6

An undesirable characteristic of ionic contrast agents is their

A)inertness.
B)neutral osmolality.
C)neutral pH.
D)dissociation into a cation and an anion when dissolved in plasma.

Question 7

Stomach examinations using barium sulfate have some degree of risk for patients who are

A)sedated.
B)mentally disabled.
C)potentially hypovolemic.
D)all of the above.

Question 8

The use of contrast material as a means for visualizing human anatomy has a long history.Regardless of the type of contrast media,the purpose for using contrast media is to

A)increase patient radiation dose and improve image quality.
B)enhance the low subject contrast of anatomic structures.
C)increase metabolism of the kidneys and liver.
D)improve the contrast between high contrast structures such as bone.

Question 9

Barium sulfate would be contraindicated for a patient with

A)colonic polyps.
B)a suspected duodenal bulb perforation.
C)diverticulosis.
D)all of the above.

Question 10

Negative contrast agents

A)appear white on images.
B)have low atomic numbers.
C)provide high x-ray beam attenuation and absorption.
D)are materials such as bone and metal.

Question 11

Nonionic iodine contrast agents differ from ionic agents in that nonionics

A)do not break down into a cation and an anion.
B)have a low pH.
C)have a small chemical structure and high osmolality.
D)are not triiodinated.

Question 12

Most adverse reactions to ionic,iodinated contrast agents are caused by

A)their pH.
B)their hydrogen concentration.
C)their osmolality.
D)the presence of iodine.

Question 13

Nonionic low-osmolality contrast agents have gained tremendous popularity with physicians as a safer choice for iodine contrast examinations.It is important to remember that nonionics

A)are much less expensive than ionics.
B)still pose a risk to renal function.
C)are more difficult to inject owing to their higher viscosity.
D)can be used on all patients,regardless of cost and risk.

Question 14

After the injection of an ionic iodinated contrast agent into a patient for a renal study,the patient complains of a warm feeling and is starting to itch.You notice the patient is developing urticaria.As you monitor the patient,you should

A)casually watch the patient and note any more symptoms because these are not unusual.
B)closely monitor the patient and look for worsening signs such as vomiting and bronchospasm.
C)inform the radiologist or physician of the patient's anaphylaxis.
D)do both b and c.

Question 15

Generally speaking,radiographic images are the result of x-ray photons being absorbed to varying degrees based on tissue density and thickness.There are five radiographic densities seen on radiographs: air or gas,water,fat,mineral,and metal.The lowest subject contrast between these five densities is between

A)bone and air.
B)water and mineral.
C)water and fat.
D)metal and air.

Question 16

Contrast media that are high in osmolality can be harmful to patients with compromised renal function.Patients who commonly have compromised kidney function include

A)patients with diabetes.
B)elderly patients.
C)renal dialysis patients.
D)all of the above.

Question 17

A double-contrast study of the colon is an example of

A)a high-contrast examination.
B)the use of both a negative and a positive contrast agent on the same image.
C)a barium sulfate and air examination.
D)all of the above.

Question 18

All of the following are true of barium sulfate as a contrast agent EXCEPT

A)when mixed with water,it dissolves completely.
B)its atomic number (Z)is 56.
C)it is chemically inert.
D)to prevent flocculation,barium sulfate is often mixed with water and sodium citrate.

Question 19

Contrast agents can be generally classified as

A)ionic and nonionic.
B)metallic and nonmetallic.
C)positive and negative.
D)aqueous and lipid based.

Question 20

The osmotic effects of ionic contrast agents are a result of the movement of

A)water from the body's cells into the bloodstream,causing increased blood volume and higher blood pressure.
B)water from the blood plasma into cells,causing them to burst.
C)iodine into cells,thereby increasing the cell membrane permeability.
D)glucose molecules into cells,increasing metabolism.

Question 21

When using any type of contrast agent for a radiographic examination,

A)the patient should have the final choice on the type of contrast used.
B)a thorough medical history must be taken by the imaging professional.
C)the cost of the contrast agent is not a consideration.
D)anaphylactic reactions are rare and of little concern.

Question 22

The radioisotope used most often in nuclear studies is

A)technetium (99mTc).
B)thorium.
C)barium iodinate.
D)iodine.

Question 23

When a nonionic contrast agent is injected into an artery such as the carotid,visualization of the artery occurs because

A)blood in the artery chemically changes into iodine.
B)iodine in the contrast agent mixes with blood and makes the artery radiopaque.
C)the contrast medium turns the vessel radiolucent.
D)the contrast agent changes into a radiopharmaceutical.

Question 24

A key distinction between radiographic studies and nuclear studies using radiopharmaceuticals is that

A)nuclear studies are generally more functional in nature.
B)radiographic examinations are more structural in nature.
C)both studies use ionizing radiation.
D)all of the above are correct.

Question 25

A responsible medical imaging professional will always maintain his or her focus on patients,particularly when any contrast agent is administered.A mandatory prerequisite to these studies is always

A)laboratory tests to determine renal function.
B)a completed registration form.
C)a thorough medical history including allergies and diseases.
D)prepayment of the cost of the contrast agent.

Question 26

A radiopharmaceutical is

A)a contrast agent.
B)any medication given to patients in radiology.
C)any medication given by a radiologist.
D)a radioactive material used for nuclear imaging with a gamma camera.

Question 27

When working with a radiopharmaceutical,the nuclear medicine professional must be aware of

A)the half-life of the isotope.
B)any isotope spills or leaks.
C)contamination of isotope that yields image artifacts.
D)all of the above.