Ch 3-5 Urinary Tract Imaging

Question 1

Current unit of radiation exposure

Answer 1

Coulombs (C)/kg

Question 2

Energy absorbed from the radiation exposure

Answer 2

Absorbed dose
Measured in gray (Gy)

Question 3

The older unit of absorbed dose

Answer 3

Rad (1 rad =100 Gy)

Question 4

Application of conversion factor to the absorbed dose

Answer 4

Equivalent dose
Measured in sieverts (Sv)

Question 5

Effective dose is defined as

Answer 5

Quantity used to denote radiation risk (expressed in sieverts)

Question 6

What is the recommended occupation exposure limit to medical personel?

Answer 6

50 mSv per year

Question 7

Reduction in radiation exposure to medical personnel is achieved by? (3)

Answer 7

(1) limiting the time of exposure; (2) maximizing distance from the radiation source; and (3) shielding.

Question 8

Mechanisms of Allergic-like Reactions (ALR)

Answer 8

(1) release of vasoactive substances including histamine
(2) activation of physiologic cascades, including complement, kinin, coagulation, and fibrinolytic systems
(3) inhibition of enzymes including cholinesterase, which may cause prolonged vagal stimulation
(4) the patient’s own anxiety and fear of the actual procedure

Question 9

Delayed contrast reactions can occur from _______

Answer 9

3 hours to 7 days after administration of contrast

14-30% after injection of ionic monomers
8-10% after the injection of nonionic monomers

Incidence of 0.5-9%

Question 10

TRUE or FALSE: Do those with previous ALR (allergic like reaction) have a risk of developing future ALR?

Answer 10

YES - 5-fold increased risk of developing future ALR

Question 11

TRUE or FALSE: If with other type of allergies, is there an increased risk of ALR?

Answer 11

TRUE - 2-3x increased risk for ALR
But those w shellfish and iodine allergies are at NO GREATER RISK

Question 12

How does anxiety affect contrast reactions?

Answer 12

More commonly occur in those w anxiety; may need reassurance but NO PREMEDS

Question 13

What are other risk factors for contrast reactions?

Answer 13

• Asthma
• Beta-blockers
• Cardiac abnormalities
• Hyperthyroidism
• Myasthenia Gravis
• Sickle cell trait / disease

Question 14

What is the surmised pathophysiology of post-contrast AKI?

Answer 14

• Vasoconstriction
• Direct tubular toxicity
• Osmotic mechanisms
• Chemotaxic mechanisms

Question 15

Defined as one of the following occurs within 48 hours after administration of iodinated contrast medium: increase in serum creatinine of >0.3 mg/dL, >50% increase in serum creatinine from baseline, or urine output reduced to <0.5 mL/kg/h for at least 6 hours

Answer 15

Contrast induced nephropathy

Question 16

Metformin should be discontinued day of study and withheld 48 hrs after due to risk of _____

Answer 16

Biguanide lactic acidosis
— Metformin stimulates intestinal production of lactic acid thus causing accumulation in those w Type 2 DM and impaired renal function

Question 17

Do you need to discontinue Metformin before gadolinium studies?

Answer 17

No when the amount used is 0.1 to 0.3mmol/kg of body weight

Question 18

Nephrogenic systemic fibrosis is related to what contrast medium

Answer 18

Gadolinium
— seen in those w severe renal dysfunction

Question 19

Extracellular MRI agents can interfere with which serum assays:

Answer 19

Calcium, Iron, Magnesium, TIBC, Zinc can all have spurious results

Biochemical assessment is more reliable 24hrs after

Question 20

What is a necessary factor in the development of nephrogenic systemic fibrosis?

Answer 20

Exposure to Gadolinium

Question 21

Whistle tip, spiral tip, and open ended catheters are classified as what type of catheters?

Answer 21

NON-OBSTRUCTING catheters

Question 22

Bulb tip, cone tip, wedge tip catheters are what kind of catheters?

Answer 22

OBSTRUCTING URETERAL CATHETERS

Question 23

Mechanisms of attenuation in ultrasound

Answer 23

(1) Reflection
(2) Scattering
(3) Interference
(4) Absorption

Question 24

Physical phenomenon that allows for information to the return to the transducer as mechanical energy

Answer 24

Reflection

Question 25

Amount of energy reflected from an interface is influenced by _____, which is influenced by tissue stiffness and density

Answer 25

Impedance

Question 26

Occurs when mechanical energy of the ultrasound waves is converted to heat; it is directly proportional to frequency

Answer 26

Absorption

Question 27

Also known as PENTETIC ACID

Answer 27

Diethylenetriaminepentaacetic acid (DTPA)

Question 28

Nuclear imaging scan used to assess functional renal obstruction
It is also extracted by the kidneys entirely by glomerular filtration

Answer 28

DTPA scan

Question 29

Radiotracer excreted by urine to determine renal split function; and assess for functional obstruction
Cleared by TUBULAR SECRETION

Answer 29

MAG3 (Mercaptoacetyltriglycine)

Question 30

Agent of choice for measuring the differences between RPF and assessing functional obstruction

Answer 30

MAG3

Question 31

Radiotracer that undergoes receptor-mediated endocytosis by the proximal tubular cells

Answer 31

DMSA

Question 32

Radiotracer best suited for imaging cortical processes (ex. Acute pyelonephritis, renal scarring)

Answer 32

DMSA (Dimeracaptosuccinic acid)