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- How
do radiopharmaceuticals detect pathology?
Once the radiopharmaceutical enters the body, the target organ collects/accumulates
it. The detection device, a gamma camera, is placed over the patient in the
area of interest and the distribution of the radiopharmaceutical is detected
and recorded. A cold, or photon-deficient, area means that there was no accumulation
of the radiopharmaceutical and that it was not carried to that area via the
circulatory system. A hot, or photon-rich area, means that there is increased
activity in that area of interest.
- In
what way does background radiation affect image quality?
Background radiation is radiation that does not contribute to the study or
is not accumulated in the area of interest. In a perfusion exam, the radioactivity
that is still circulating in the blood or in the organs near the myocardium
is considered background radiation. The more radiation that exists outside
of the area of interest, the poorer the quality of the image.
- What
are the biokinetic benefits of MYOVIEW?
MYOVIEW exhibits four biokinetic principles essential to image quality: prompt
myocardial uptake and rapid clearance1-3;
proportional uptake to reveal reduced blood flow to ischemic regions1-2;
good target-to-background ratio3; and myocardial retention with little or
no redistribution.2-3
- How
does the heart-to-liver clearance of MYOVIEW affect imaging?
MYOVIEW clears the liver rapidly and so reduces artifacts from surrounding
organs.2-3 This allows for timely imaging, as soon as 15 minutes and up to
4 hours postinjection.3 This increases patient throughput and presents the
opportunity for timely patient management.3-4 Rapid clearance from extracardiac
organs optimizes heart visualization and thus enhances diagnostic confidence.3-4
- Is
MYOVIEW indicated for pharmacologic stress exams?
Yes. MYOVIEW is indicated for scintigraphic imaging of the myocardium to
identify changes in perfusion induced by pharmacologic stress in patients
with known or suspected coronary artery disease.
- How
does perfusion imaging impact diagnosis in the emergency department?
In a multicenter trial, it has been demonstrated that rest MYOVIEW SPECT
myocardial perfusion imaging in the emergency department in patients with
chest pain and normal or nondiagnostic ECG has a high negative predictive
value (98%) for the detection of acute infarction.6
In studying patients with known or suspected coronary artery disease, care should be taken to ensure continuous cardiac monitoring and the availability of emergency cardiac treatment. As with all injectable drug products, allergic reactions, and anaphylaxis may occur.
Pharmacologic induction of cardiovascular stress may be associated with serious adverse events, such as myocardial infarction, arrhythmia, hypotension, bronchoconstriction, and cerebrovascular events. Caution should be used when pharmacologic stress is selected as an alternative to exercise; it should be used when indicated and in accordance with the pharmacologic stress agent's labeling. The most common adverse reactions reported from post-marketing experience included rash, urticaria, abnormal vision, allergic reactions, and fever.
References:
1. MYOVIEW
prescribing information. 2. Iskandrian AE, Verani MS. Nuclear imaging techniques. In: Topoi EJ, ed. Textbook
of Cardiovascular Medicine. Philadelphia, Pa: Lippincott-Raven Publishers;
1998:1367-1371. 3. Higley B, Smith FW, Smith T, et al. Technetium-99m-1,2-bis[bis(2-ethoxyethyl)
phosphino]ethane: human biodistribution, dosimetry and safety of
a new myocardial perfusion imaging agent. J Nucl Med. 1993;34:30-38. 4. Münch G, Neverve J, Matsunari I, Schroter G, Schwaiger M. Myocardial technetium-99m-tetrofosmin
and technetium-99m-sestamibi kinetics in normal subjects and patients
with coronary artery disease. J Nucl Med. 1997;38:428-432. 5. Heller GV, Stowers SA, Hendel RC, et al. Clinical value of acute rest technetium-99m
tetrofosmin tomographic myocardial perfusion imaging in patients
with acute chest pain and nondiagnostic electrocardiograms. J Am
Coll Cardiol. 1998;31:1011-1017. |