Nuclear Cardiology dx tests and procedures/protocols/artifacts Flashcards
Which of the following is an indication for performing pharm stress in lieu of a treadmill test for SPECT MPI?
a. severe symptomatic PAD
b. chronotropic incompetence
c. LBBB
d. neurologic and MSK disorders
e. all of above
E.
Which of the following is not a contraindication to performing a pharm stress test with adenosine?
a. pentoxifylline
b. caffeinated food or bev <12 hrs prior to stress
c. severe COPD w/ ongoing wheeze
d. Dipyridamole or aminophylline <24 hrs prior to stress
E. 2nd or 3rd deg AV block or sick sinus syndrome w/o PPM
A.
adenosine is a nonselective agonist that causes coronary vasodilation when it activates the A2A receptor. A1, A2B, and A3 when activated produce most of side effects including chest pain, bronchiolar constriction, mast cell degranulation (flushing), and neg chronotropic, inotropic, and dromotropic effects.
Caffeine and aminophyline bind to adenosine receptors w/o stimulations. aminophylline should be held 24-48hrs prior to testing. dipyridamole should be held for 24-48hrs. Pts with severe COPD and active wheeze should NOT undergo adenosine/dipyridamole stress due to A2B/A3 receptors causing constriction. OK for albuterol before.
In which of the pts w/ an STEMI is there an approp, role for SPECT MPI?
a. stable pts who have undergone cor angio and PCI
b. decomp CHF pts w/ life-threatening arrhythmias and hemodynamic instability
c. stable pts who have undergone successful reperfusion and cor angiography
d. stable pts scheduled for coronary angio
e. stable pts prior to d/c who are not scheduled to undergo cardaic cath
E. is a class I indication. looking for inducible ischemia would change the treatment plan
49 yo woman is being evaluated for atypical chest pain. She had an MI 2 yrs ago and received a BMS to the mid LAD> After consulting her pcp she is concerned about the spect mpi. which of the following regarding spect mpi in women is/are correct?
a. women have smaller hearts, which improves image quality and accuracy
b. breast attenuation is not reduced by using tech-99m radiopharm
c. spect diagnostic specificity in women is above 90%
d. best use of the test is in women wiht intermediate to high pretest likelihood for CAD
e. PET has the same diagnostic accuracy as spect in women
D.
Small LV chamber size adversely affects image quality and diagnostic accuracy esp if using thall 201. Women have smaller hearts than men, which diminishes accuracy.
breast attenation can produce anterior wall defects that may mimic LAD infarct. tech-99m agents with ecg gating have less attenuation and give better gated images than thall 201, improves accuracy by improving specificity.
specificity for dx CAD is reduced to 65-70% due to breast tissue artifact but can be improved to 85-90% when integrating rotating projections, wall motion, and attenuation correction.
PET has higher dx accuracy than spect in women with improved accuracy by more successfully addressing breast attenuation, obesity, and small heart
An elderly female pt with renal impairment and chest pain is referred for spect mpi. Which of the following statements is true?
a. more severe renal dysfunction, the lower the likelihood of an abnormal spect
b. mortality is increased in pts with a normal MPI and moderate to severe renal dysfunction
c. thall 201 spect stress testing is not effective in renal-impaired pts for predicting high risk of a major cardiac event
d. pts who undergo spect imaging prior to transplant are found to have ischemia in up to 10% and they have a high adverse cardiac event rate
D. Presence of CKD predisposes to accelerated atherogenesis and increased CV risk. Mortality almost doubles in pts with moderate or seveere CKD in presence of abnormal stress spect mpi; the more severe ckd higher the probability of having an abnormal spect study, and more severe ischemia.
Tech-99m labeled perfusion tracers are most commonly used to assess resting adn stress myocaridal perfusion. studies have shown admin of nitrates prior to the resting injection images results in which of the following?
a. improve readers ability to detect viable myocardium in severely hypoperfused segments
b. improves overall delivery of tracer to myocardium and therefore improves the quality of images
c. interferes with interpretation of the stress images
d. is of no value, since tech-99m labeled agents do not redistribute
e. none of above
A.
use of nitrates in conjunction wiht rest tech-99m spect mpi has been shown to improve detection of viable myocardium. Compared iwht resting tech-99m studies alone, nitrate enhanced spect has greater ability to predict improvement of regional fxn after revascularization and to provide important prognostic infor.
which of the following statements regarding the general sensitivity and specificity for detection of CAD of various cardiac stress testing image methods is true?
a. pet is more sensitive but least specific
b. spect mpi is more sensitive and specific compared to exercise ecg
c. stress echo is more sensitive but less specific than spect
d. sensitivity and specificity of all tests are independent of the population studied
B.
Cardiac pet has the highest sensitivity and specificity of currently available noninvasive modalities. spect has a higher sensitivity and lower specificity in comparison to stress echo. stress ecg vs spect, speect has higher sensitivity and specificity.
Exercise spect mpi is the best initial test in which of the following situations?
a. 27 year old female pt with sharp chest pain, no risk factors, normal resting ecg and able to exercise
b. 72 yo male with atypical cp, dm, and htn, lvh and able to exercise
c. 69 yo with atypical cp, new af, an ecg with 2mm st depression and unable to exercise
d. a symptomatic 76 yo female with intreasing typical cp, 3vessel cabg 2 yrs ago, normal ecg, and able to exercise
B.
in female pt with low pretest probability for cad who has a normal baseline ecg and capable of exercising, spect mpi is not indicated and a stress ecg is best. pt with intermediate probability of cad and lvh on baseline ecg is best candidate for exercise stress spect. the ecg alone would not be diagnostic and imaging is required.
Failure to achieve 85% of the max age predicted heart rate during spect imaging may reduce the diagnostic performance by which of the following?
a. reducing the size and severity of the perfusion defects
b. interfering with the acquisition of ecg-gated images
c. not allowing enough time for trace uptake
d. lowering the normalcy rate of the test
which of the following is an advantage of dual isotope spect mpi?
a. flexibility of performing 1 day stress/rest, rest/stress or 2 day sequence
b. existence of validated attenuation correction algorithms for thallium-20 but not tech-99
c. improved efficiency in the nuclear card lab
d. easier interpretation of artifacts
Which of the following variables in sot part of the Duke TReadmill Score?
a. anginal cp
b. chronotropic incompetence
c. magnitude of st segment changes
d. exercise time
B.
chronotropic incompetence is predictive of future cardiac events
Which of the following is not a contraindication for spect stress MPI?
a. decompensated chf
b. unstable angina
c. stable post-MI
d. critical valvular disease
C.
Relative to a treadmill exercise ecg testing in women, spect mpi does which of the following?
a. is comparable in sensitivity and specificity
b. improves specificity
c. improves the specificity but compromises the sensitivity
d. improves the sensitivity but compromises the specificity
B.
spect improves specificity without compromising sensitivity in the detection of CAD in women compared to exercise ecg stress testing alone
Which of the following does not result in poor SPECT quality or creation of artifacts?
a. body size and habitus
b. LVH
c. patient gender
d. patient position relative to the camera
B.
SPECT MPI w/o attenuation correction is adversely influenced by the presece of different tissue densities and the distance between the heart and gamma camera. Camera distance from the patient, ie obesity or poor positioning, results in lower counts and poor quality studies. breast size, density, and position and diaphragmatic position and thickness all cause attenuation resulting in low counts in the covered portions of the myocardium and the appearance of less tracer uptake in the presence of normal blood flow. LVH may improve counts which results in better-quality images with the risk of hiding small areas of ischemia.
In a male patient undergoing spect mpi, which of the following is least likely to cause an artifact?
a. abdominal protuberance
b. anterior chest attenuation related to obesity
c. shifting breast artifact
d. elevated diaphragm
C. Abdominal protuberance due to obesity or ascites can cause elevation of the diaphragm and greater inferior wall attenuation and the need to position the gamma camera head further from the patient, which will lower total counts and give poor image quality. chest wall obesity also requires positioning the gamma camera head further from the pt, and mal pts may have substantial gynecomastia. The breast tissue is unlikely to shift between rest and stress images.
Breast attenuation is likely to create spect artifacts resulting in which of the following?
a. decreased sensitivity in the rca territory
b. decreased specificaty in the rca territory
c. decresed sensitivity in the lad
d. decreased specificity in LAD
D.
breast artifacts are seen in 40% of myocardial perfusion images in women often present in the anterior wall leading to a lower specificity to correctly diagnose CAD in LAD.
All of the following are measures employed to limit or recognize attenuation artifacts in spect mpi except:
a. utilizing higher-energy pharmaceutical
b. reviewing rotating projection images
c. performing quantitative analysis
d. using pharmacologic in place of exercise stress
D.
use of tech-99 radiolabeled perfusion agents results in less attenuation and scatter and gives higher-quality images than thall-201. Review of the rotating projection images in cine format allows identification of the position of the diaphragm and breasts and estimation of the movement of the heart in vertical and horizontal planes. Using gender-matched normal files for quantitative analysis helps to eliminate attenuation artifact. Type of stress does NOT influence attenuation while the higher background usually seen with pharm stress results in poor image quality.
Quantitative analysis of SPECT MPI has been used to help differentiate attenuation artifacts from true perfusion defects. Comparison of a given patient to which of the following normal databases gives the best specificity?
a. age matched
b. gender matched
c. weight matched
d. risk factor matched
B.
Normal databases are usually matched for type of protocol, form of stress, adn the type of agent. Gender-matched normal files improve specificity most by accounting for differences in amount of breast attenuation.
Prone imaging improves spect mpi accuracy b/c it allows recognition of which of the following?
a. diaphragmatic attenuation
b. patient motion
c. breast attenuation
d. residual liver activity
A.
Prone imaging provides greater separation between heart and diaphragm, so there is less inferior wall attenuation in comparison to a suine image. Pts are usually imaged both prone and supine and a comparison is made. Most available normal files are for supine imaging. Pt motion, breast attenuation, and residual liver activity can be seen on both prone and supine.
Which of the following is a true statement about gated spect mpi?
a. it has a very high spatial and temporal resolution compared to echocardiographic methods.
b. it is generated from the best cardiac cycles during image acquisition
c. it improves specificity and reader confidence in the spect interpretation
d. EF measurements can help in the dx of diastolic dysfunction
C.
Traditional gated spect has a low spatial and temporal resolution compared to echo methods. Spatial resolution varies from 14-16mm and the temporal resolution is restricted to 8 or at most 16 time frames for the RR interval. Greater temporal resolution is limitied by the resulting low counts in each time interval. ECG gated SPECt is generated from all teh cardiac cycles throughout the acquisition process. Gated images can help differentiate perfusion defects due to scar, which do not move or thicken, and attenuation defects that move and thicken. The EF is a measure of systolic function.
Which of the following maneuvers is most likely to eliminate liver retention with tech-99 radiotracers and improve image quality?
a. having ptient drink two 8oz glasses of water and imaging immediately after pharm stress
b. having patient drink 4oz glasses of a carbonated drink and imaging immediately after pharm stress
c. waiting 45 mins before imaging following pharm stress
d. switching the patient from exercise to pharm stress
C.
Both tech-99 sestamibi and tetrofosmin are cleared from the liver in a time dependent manner. Having the patietn drink large amounts of water or small amounts of a carbonated liquid which will release gas, will not enhance liver clearance and the recommended imaging time after pharm stress or rest is 30-60mins. Imaging immediately after pharm stress will result in significant liver retention. Delaying image acquisition and adding exercise to the stress tests can lead to better clearance and therefore lower liver and GI counts.
which of the following is/are the most appropriate reasons for using pharm stress testing?
a. PAD limiting exertion
b. presence of LBBB or PPM
c. failure to achieve target HR with dynamic exercise
d. all of above
D.
w/ a LBBB or V paced rhythm septal defect may be observed with exercise stress and decreased when using pharm stress
Although vasodilators are generally preferred for pharm stress spect mpi, in which of the following situations is dobutamine the most appropriate stress agent?
a. pt taking BB
b. pt who are in AF
c. Pt in whom higher-sensitivity spect study is desired
d. pt who are being treated with theophylline
D.
Dobutamine is a stress inotropic agent that can be used for pharm stress testing in pts with active airway disease or in patients being treated with theophylline. In such patients dipyridamole, adenosine, or regadenoson may cause further airway decompensation by stimulation of adenosine a2b or a3 receptors that mediate bronchospasm. Theophylline blocks the adenosine receptors and is used to treat side effects induced by vasodilators.
Which of the following is the most appropriate explanation for why dipyridamole, regadenoson, and adenosine are effective pharm spect stress agents?
a. ability to increase coronary blood flow 2.4-4.5x above baseline
b. Increase in HR and BP
C. Dilation of epicardial coronary vessels
d. dilation of critically stenosed coronary vessels
A.
all of these agents act as direct or indirect vasodilators of the resistance arterioles varying from 2.4-4.5x above baseline blood depending on the agent. Regadenoson gives a more physiologic increase in blood flow relative to adenosine and dipyridamole, which give a greater response.
