SP11:Genitourinary System Scintigraphy

Question 1

What is the imaging protocol that was most probably used to obtain the images in Fig. 1?
(rapid change in appearance of the kidney in early images)(activity in the kidney in the last image, and the appearance of arterial flow on just one image)
(a)Consecutive 1 s images for 15 s

(b) Consecutive 3 s images for 45 s
(c) 15 consecutive 10 s images
(d) 15 consecutive 15 s images

Answer 1

(b) Because of the rapid change in appearance of the kidney in early images, one can assume that these images are of very short duration, ruling out choices c and d. Because of the activity in the kidney in the last image, and the appearance of arterial flow on just one image, one can assume that they are 3 s images taken over 45 s. The arterial phase would be more clearly seen on multiple images if they were 1 s images.

Question 2

Which of the following describes the activity on delayed static images in a patient with testicular torsion?
(a)Decreased

(b) Normal
(c) Increased
(d) Variable

Answer 2

(a) On delayed images, there is often decreased or even absent activity in early phase torsion. Perfusion may show normal or decreased activity unless the torsion is late phase. In this case, perfusion is increased in the tissue surrounding the testicle.

Question 3

Clearance of 99mTc MAG3 is by:
(a)Active transport

(b) Tubular secretion
(c) Glomerular filtration
(d) None of the above

Answer 3

(b) 99mTc MAG3 is cleared by the proximal tubules. 99mTc DTPA is cleared by glomerular filtration which makes it useful for estimating glomerular filtration rate (GFR). 99mTc DMSA binds to proximal renal tubules, is useful for imaging the renal parenchyma, and clears very slowly in the urine. 99mTc GH is cleared by both glomerular filtration rate and the renal tubules and is also useful for imaging the renal cortex.

Question 4

Which renal imaging agent allows imaging at 6 h after injection?
(a)99mTc MAG3

(b) 99mTc DTPA
(c) 99mTc GH
(d) 99mTc DMSA

Answer 4

(d) Injected 99mTc DMSA will remain concentrated in the renal cortex for many hours after injection. Delayed imaging is often necessary to have sufficient activity in the kidneys relative to background if the patient has impaired renal function.

Question 5

A patient with Cushing’s syndrome might receive a dose of:
(a)131I NP-59 to study the adrenal cortex

(b) 131I NP-59 to study the adrenal medulla
(c) 131I MIBG to study the adrenal cortex
(d) 131I MIBG to study the adrenal medulla

Answer 5

(a) 131I NP59 binds to receptors on the adrenal cortex and may be useful in Cushing’s syndrome and hyperaldosteronism and hyperandrogenism. MIBG is taken up by chromaffin cells which are in the adrenal medulla and the paraganglia of the sympathetic nervous system; it is usually labeled with 131I and is used to image neuroectodermally derived tumors such as pheochromocytomas, neuroblastomas, and paragangliomas.

Question 6

A patient who receives an injection of 131I MIBG for the detection of pheochromocytoma should also receive:
(a)Potassium perchlorate

(b) Dipyridamole
(c) Lugol’s solution
(d) Cimetidine

Answer 6

(c) Lugol’s solution will block some of the uptake of 131I by the thyroid.

Question 7

Which of the following is used to image the adrenal cortex?
(a)131I MIBG

(b)131I NP-59

Answer 7

(b)131I NP59 binds to receptors on the adrenal cortex and may be useful in Cushing’s syndrome and hyperaldosteronism and hyperandrogenism. MIBG is taken up by chromaffin cells which are in the adrenal medulla and the paraganglia of the sympathetic nervous system; it is usually labeled with 131I and is used to image neuroectodermally derived tumors such as pheochromocytomas, neuroblastomas, and paragangliomas.

Question 8

99mTc DMSA delivers a relatively high radiation dose to the kidneys because:
(a)20 mCi are normally injected for a renal study.

(b) There is a long effective half-life in the kidneys
(c) There is a long physical half-life.
(d) A high-energy photon is emitted.

Answer 8

(b) Although the dose can be lower than other 99mTc renal imaging agents and the photon is not high energy, the radiation dose to the kidney is higher than with other agents because the DMSA remains fixed in the kidneys for many hours.

Question 9

Which of the following is excreted by glomerular filtration?
(a)99mTc DTPA

(b) 99mTc DMSA
(c) 99mTc MAG3
(d) 99mTc GH

Answer 9

(a) 99mTc MAG3 is cleared by the proximal tubules. 99mTc DTPA is cleared by glomerular filtration which makes it useful for estimating glomerular filtration rate (GFR). 99mTc DMSA binds to proximal renal tubules, is useful for imaging the renal parenchyma, and clears very slowly in the urine. 99mTc GH is cleared by both glomerular filtration rate and the renal tubules and is also useful for imaging the renal cortex.

Question 10

Indications for renal scanning with radionuclides include:
(a)Assess blood flow to transplanted kidneys

(b) Allergy to iodinated contrast
(c) Assess function of native kidneys
(d) Evaluation of space-occupying lesions
(e) All of the above

Answer 10

(e) Although Ct and MR can evaluate renal anatomy, radionuclide imaging is still useful for all of the indications listed.

Question 11

Normal glomerular filtration rate is:
(a)25 ml/min

(b) 50 ml/min
(c) 100 ml/min
(d) 125 ml/min

Answer 11

(d) Glomerular filtration is the process that removes excess water, salts, and urea from the blood. This filtration takes place in the glomeruli following which the filtered blood flows into Bowman’s capsule. GFR varies according to age, race, and gender, but the approximate normal value is 120-125 ml/min for both kidneys in young and middle-aged adults.

Question 12

For visualizing intraparenchymal lesions in the kidneys, the radiopharmaceutical of choice form the list below is:
(a)99mTc DMSA

(b) 99mTc DTPA
(c) 99mTc MAG3
(d) 131I OIH

Answer 12

(a) 99mTc MAG3 is cleared by the proximal tubules. 99mTc DTPA is cleared by glomerular filtration which makes it useful for estimating glomerular filtration rate (GFR). 99mTc DMSA binds to proximal renal tubules, is useful for imaging the renal parenchyma, and clears very slowly in the urine. 99mTc GH is cleared by both glomerular filtration rate and the renal tubules and is also useful for imaging the renal cortex.

Question 13

What is the preparation for renal functional imaging with 99mTc MAG3
(a)NPO for at least 4 h.

(b) Patient must be well hydrated.
(c) Patient must not void for at least 1 h before imaging.
(d) Patient must drink nothing for 2 h prior to the examination.
(e) All patients must be catheterized.

Answer 13

(b) Patients undergoing renal imaging with 99mTc MAG3 should be well hydrated and should void just before the exam. The renogram may show delayed peak activity and delayed clearance of radiopharmaceutical if the patient is dehydrated.

Question 14

Thirty minutes after injection of 8 mCi of 99mTc MAG3, there is significant activity remaining in the renal pelvis. What will most likely follow?
(a)Patient will be asked to void before reimaging.

(b) A diuretic will be administered.
(c) Imaging will be extended for 20 min.
(d) All of the above.

Answer 14

(d) If an obstruction is suspected, a diuretic can be administered, the patient should be asked to void, or be catheterized, and further imaging may be carried out.

Question 15

If after administration of furosemide, a patient still has activity in the renal calyces, there is probably:
(a)Poor renal function

(b) Renal artery occlusion
(c) Renal infarction
(d) Collecting system obstruction

Answer 15

(d) Diuretic renography, usually performed using 99mTc MAG3 with furosemide, can help differentiate between functional abnormalities and anatomic obstruction. Furosemide will increase the pressure in the renal pelvis causing the tracer to move from the collecting system, unless the obstruction is anatomic; in this case, there would be little change in the distribution of the tracer.

Question 16

Performing an evaluation of a renal transplant includes the following considerations:
(a)The best imaging will be obtained posteriorly.

(b) Detector face should be centered over the right or left iliac fossa.
(c) A lower dose of 99mTc MAG3 should be given to protect the transplant.
(d) Uptake of radiopharmaceutical is usually delayed in the transplanted kidneys relative to native.
(e) All of the above.

Answer 16

(b) Imaging of transplants is performed anteriorly with the detector centered over the relevant iliac fossa.

Question 17

The left kidney is usually lower than the right because of the spleen.
(a)True

(b)False

Answer 17

(b) The right kidney is often, but not always, lower than the left, probably because of its proximity to the liver.

Question 18

Setting up for a scrotal scan includes:
(a)Elevating the scrotum with towels or a sling fashioned from tape across the thighs

(b) Taping the penis to either leg
(c) Having the patient sit on the imaging table over the detector face
(d) Having the patient erect with the pelvis against the detector face

Answer 18

(a) The patient should tape the penis to the stomach and elevate the scrotum toward the detector head with a sheet or towel, or by fashioning a sling form tape. Additionally a lead shield may be placed under the scrotum to minimize background activity.

Question 19

Torsion of the testicle:
(a)Is synonymous with epididymitis

(b) Is not painful
(c) Is a surgical emergency
(d) May be treated with antibiotics

Answer 19

(c) Testicular torsion is a painful condition in which the spermatic cord is twisted, and it usually requires surgical correction within 5-6 h. It often follows trauma, but may also be caused by a congenital abnormality, or may be spontaneous. The involved testicle is usually swollen.

Question 20

The adult dose of 99mTc pertechnetate for imaging the testicles is:
(a)1-2 mCi

(b) 2-4 mCi
(c) 5-10 mCi
(d) 10-20 mCi

Answer 20

(d) Dosage varies according to the lab and ranges form 5 to 30 mCi; 20 mCi is a commonly recommended dose.

Question 21

The kidneys are normally perfused via the iliac artery.
(a)True

(b)False

Answer 21

(b) The blood supply to the native kidneys comes from the renal arteries which arise from the descending aorta.

Question 22

Radionuclide cystography is most often performed to:
(a)Determine transplant function

(b) Evaluate renal perfusion
(c) Detect vesicoureteral reflux
(d) Visualize space-occupying lesions in the bladder

Answer 22

(c) Radionuclide cystography is performed to evaluate patients for vesicoureteral reflux. The radiopharmaceutical is introduced into the bladder with saline, and the patient is imaged during bladder filling and voiding to detect reflux of activity from the bladder into the ureters.

Question 23

The expected bladder capacity for a 6-year-old child is:
(a)50 ml

(b) 120 ml
(c) 240 ml
(d) 500 ml

Answer 23

(c) A formula for estimating bladder capacity is needed to prepare an appropriate amount of saline for bladder filling. The formula used is as follows: (Age +2) x 30 ml.

Question 24

The reason for calculation of expected bladder capacity before radionuclide cystography is:
(a)To use the result in calculations of residual volume

(b) To use the result in calculations of reflux volume
(c) To have an idea of when maximum bladder filling will be reached
(d) All of the above

Answer 24

(c) A formula for estimating bladder capacity is needed to prepare an appropriate amount of saline for bladder filling. The formula used is as follows: (Age +2) x 30 ml. Quantitative information can be obtained by comparing counts in the bladder pre- and post-voiding and by using regions of interest in the ureters.

Question 25

A technologist is performing radionuclide cystography on a 4-year-old girl. During bladder filling with 99mTc in saline, there is leakage from around the catheter. What impact will this have?
(a)Quantitative information will be unreliable.

(b) The detector may become contaminated if it has not been properly protected with plastic-backed, absorbent paper.
(c) The chance to image any reflux is lost.
(d) (a) and (b).
(e) (b) and (c).

Answer 25

(d) The possibility to image any reflux will not be lost, but there is danger that the detector and other equipment will become contaminated, and some quantitative information may be unreliable.

Question 26

Which of the following describes normal images form radionuclide cystography during bladder filling?
(a)Increasing activity in the bladder over time

(b) Homogeneous activity in both ureters
(c) Decreasing activity in the kidneys over time
(d) None of the above

Answer 26

(a) Normal cystography will show an increase in activity in the bladder during filling and decreasing activity during voiding with no activity in the ureters or kidneys.

Question 27

Preparation for a pediatric radionuclide cystography includes:
(a)Patient catheterization

(b) Calculation of expected bladder capacity
(c) Taking measures to prevent contamination of equipment, personnel, and imaging room
(d) Emptying the patient’s bladder
(e) All of the above

Answer 27

(e) Expected bladder capacity must be calculated. It is important to ascertain the patient’s ability to void on request, and the detector head and surrounding equipment should be protected against contamination form the radioactive urine. The patient should be catheterized and the bladder should be emptied before filling.

Question 28

In normal patients, a volume of up to 1.5 ml may reflux into the ureters and kidneys at maximum bladder filling.
(a)True

(b)False

Answer 28

(b) Any reflux into the ureters or kidneys is abnormal. Small volumes of reflux into the distal ureters may be difficult to detect.

Question 29

Voiding images taken during radionuclide cystography should be:
(a)Dynamic images

(b) Acquired based on information density
(c) 5 min images
(d) Taken for 500 K counts

Answer 29

(a) Imaging should be dynamic during filling and voiding.

Question 30

Which of the following is not true regarding glomerular filtration rate?
(a)It usually becomes abnormal before serum creatinine levels become abnormal.

(b) It is typically obtained through the use of 99mTc DTPA.
(c) It can be determined only by taking blood or urine specimens.
(d) It is a measure of the ability of the kidneys to clear inulin from the plasma.
(e) All except b.

Answer 30

(c) Glomerular filtration rate is the amount of fluid filtered from the glomerular capillaries to the Bowman’s capsule in a given amount of time, normally expressed as ml/min. It is defined as the ability of the kidneys to clear inulin from plasma; inulin is a substance that is filtered by the glomeruli and is not secreted or reabsorbed by the tubules. Significant kidney function may be lost before serum creatinine becomes abnormal, so GFR is an important measurement. 99mTc DTPA is cleared by the glomeruli and is used for measuring glomerular filtration rate.

Question 31

Which radiopharmaceuticals can be used to determine effective renal plasma flow?
(a)99mTc MAG3

(b) 131I OIH
(c) 99mTc DTPA
(d) (a) and (b) only
(e) (a) and (c) only

Answer 31

(d) Renal plasma flow is defined as the clearance of para-aminohippurate (PAH, which is secreted and filtered by the renal tubules) from plasma. In nuclear medicine, effective renal plasma flow (ERPF) has been measured using 131I OIH in the past and more recently MAG3. It is termed effective because it does not equal the clearance of PAH, but approximates it.

Question 32

An advantage of GFR and ERPF measurements over other indicators of renal function such as BUN and creatinine is that the function of each kidney can be determined separately.
(a)True

(b)False

Answer 32

(a) Blood tests with implications for renal function, like BUN and creatinine, only capture information about overall renal function. Quantitative studies of GFR and ERPF can provide information about individual kidney function.

Question 33

Which saline bottle would be sufficient to fill the bladder of an 8-year-old during radionuclide cystography?
(a)125 ml

(b) 250 ml
(c) 400 ml
(d) None of the above

Answer 33

(c) A formula for estimating bladder capacity is needed to prepare an appropriate amount of saline for bladder filling. The formula used is as follows: (Age +2) x 30 ml.

Question 34

Which renal imaging agent requires the highest administered dose?
(a)99mTc DTPA

(b) 131I OIH
(c) 99mTc MAG3
(d) 99mTc DMSA
(e) (a) and (c)

Answer 34

(e) 99mTc DMSA is usually administered in lower doses because of its retention in the kidney. 131I OIH, with its beta emissions and long half-life, also has a lower dosage (but OIH may also be tagged with 123I). 99mTc MAG3 and 99mTc DTPA have similar dosages.

Question 35

A technologist prepares a radiopharmaceutical for renal imaging at 8:00 a.m. The patient arrives late at 12:15 p.m., and therefore a new kit has to be made. The radiopharmaceutical being used is:
(a)99mTc MAG3

(b) 99mTc DMSA
(c) 99mTc DTPA
(d) 99mTc GH

Answer 35

(b) DMSA should be discarded after 4 h.

Question 36

On a normal renal scan, gallbladder activity is noted. This indicates that the scan was performed using:
(a)99mTc DMSA

(b) 99mTc DTPA
(c) 99mTc GH
(d) 99mTc MAG3

Answer 36

(d) A small percentage of 99mTc MAG3 may be taken up in the liver and gall bladder in normal patients, and this may be more pronounced in patients with poor renal function.

Question 37

Following the injection of 131I NP-59, imaging for adrenal lesions is performed:
(a)6 h later

(b) 24-48 h later
(c) 48-72 h later
(d) 5-7 days later
(e) None of the above

Answer 37

(d) Imaging usually begins at 5-7 days but may commence earlier depending on the history of the patient (e.g., suspected hyperaldosteronism) and the questions asked of the exam.

Question 38

The adrenal glands are:
(a)Superior to the kidney

(b) Inferior to the kidney
(c) Anterior to the kidney
(d) Posterior to the kidney

Answer 38

(a) The adrenal glands sit atop the kidneys.

Question 39

Which of the following is a tuft of capillaries?
(a)Loop of Henle

(b) The glomerulus
(c) Renal pyramid
(d) Collecting tubule

Answer 39

(b) The glomerulus is a tuft of capillaries within the nephron. The loop of Henle is the hairpin loop that the tubule makes. Distal tubules from several nephrons join to form the collecting duct. The renal pyramids are part of the renal medulla which empty into the renal pelvis.

Question 40

What percentage of cardiac output is directed to the kidneys?
(a)10%

(b) 25%
(c) 40%
(d) 50%

Answer 40

(b) About 25% of the cardiac output is directed to the kidneys.

Question 41

On otherwise normal static images of the kidneys, the lower poles of the kidneys appear slightly decreased in intensity relative to the upper poles. Why is this?
(a)There is probably an obstruction of the collecting system.

(b) There are bilateral space-occupying lesions in the lower poles.
(c) The adrenal glands are attenuating the activity from the lower poles.
(d) The lower poles of the kidneys are situated slightly anterior to the upper poles.

Answer 41

(d) If the images are obtained posteriorly, the lower poles may appear to have slightly less activity than the upper poles because the lower poles are often situated slightly anterior to the upper poles.

Question 42

In a patient with renal artery stenosis:
(a)A post captopril study will show increased GFR.

(b) A post captopril study will show decreased GFR.
(c) A post captopril study will show GFR to be unchanged.

Answer 42

(b) Patients who have renal artery stenosis, when given an ACE (angiotensin-converting enzyme) inhibitor, will show a decrease in GFR. Therefore, captopril renography is an effective examination to determine whether renal artery stenosis is the cause of hypertension.

Question 43

When performing captopril renography, captopril should be administered:
(a)1 h prior to the injection of radiopharmaceutical

(b) 20 min after the injection of radiopharmaceutical
(c) Only if activity persists in the renal pelvis 20 min after radiopharmaceutical administration
(d) At the same time as the injection as of radiopharmaceutical

Answer 43

(a) In captopril renography, the captopril is administered orally 1 h before the injection of the radiopharmaceutical.

Question 44

Preparation for captopril renography includes:
(a)ACE inhibitors stopped

(b) Fasting to enhance absorption of oral captopril
(c) Well-hydrated patient
(d) All of the above
(e) None of the above

Answer 44

(d) The patient should be well hydrated, fasting, and off ACE inhibitors before the study is begun. The length of time that the medications should be held depends on the type of medication, typically 3 days for captopril and 1 week for some other medications.

Question 45

Captopril is used when:
(a)The patient is suspected of having an obstruction.

(b) The patient is suspected of having renovascular hypertension.
(c) The patient has high blood pressure.
(d) The patient is taking diuretics.

Answer 45

(b) Captopril renography is used when the patient is suspected of having renovascular hypertension, but since only 1-4% of hypertension is due to renovascular hypertension, it is not used as a screening test in all cases of hypertension.

Question 46

What will probably be done next, given the renogram shown in Fig. 2?(poor renal function, no excretion)
(a)The patient will undergo captopril renography.

(b) Posterior obliques should be take.
(c) A diuretic will be given to rule out mechanical obstruction.
(d) The exam will be ended.
(e) None of the above.

Answer 46

(c) The renogram shown indicates poor renal function. There appears to be no excretion, so a diuretic could be administered in the hope of inducing excretion.

Question 47

When performing ACEI renography, all of the following is correct except for:
(a)Patient should be well hydrated.

(b) Severe hypotension may occur due to administration of ACEI.
(c) Blood pressure and pulse should be monitored continuously throughout the study.
(d) If a patient is already on ACEI therapy, no further ACEI is needed before ACEI renography.

Answer 47

(d) If a patient is already on ACEI therapy, ACEI should be discontinued for 3-5 days (depending on half-life) before ACEI renography.