Clinical trial NCT01412827: Accuracy of Half of the Usual Radiotracer Dose in SPECT
Official title: Diagnostic and Prognostic Accuracy of Stress SPECT Myocardial Perfusion Imaging With Half the Usual Radiotracer Dose
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Coronary Artery Disease
Keywords: Single-photon emission computed tomography
myocardial perfusion imaging
rest/stress
treadmill
persantine
half-dose
radiotracer
tetrofosmin
Thallium
cadmium zinc telluride
diagnostic
prognostic
Lead sponsor: Ottawa Heart Institute Research Corporation
Sponsor class: OTHER
First posted: 2011-08-09
Enrollment: 18
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: DIAGNOSTIC

Brief summary: There has been a shortage of nuclear isotopes, not only in Canada but around the world. New, more sensitive SPECT cameras can obtain better images in shorter scan times. These cameras have also shown the ability to use a smaller dose of radioisotope to obtain the images. New software has been tested on the standard camera, the GE Infinia-Hawkeye SPECT/CT. The Diagnostic Imaging Department of The University of Ottawa Heart Institute has also acquired a new camera, the Discovery NM530c CZT and has been doing heart scans in shorter times. The investigators will now be looking at the quality of images using less isotope during SPECT myocardial perfusion imaging for diagnostic and prognostic purposes.

Detailed description: SPECT MPI is well accepted as a reliable and cost-effective tool for diagnosis, risk stratification and management of patients with suspected or known coronary artery disease (CAD) (1;2). MPI represents approximately 40% of nuclear medicine patient studies and most of these use 99mTc-sestamibi or 99mTc-tetrofosmin(3). Rest/stress MPI using 99mTc-sestamibi and 99mTc-tetrofosmin uses more tracer doses than many other nuclear medicine tests and thus account for \>50% of injected radiotracer activity(3). Thus, interruptions in the supply of 99Mo, the parent isotope of 99mTc, significantly affect stress MPI imaging and associated patient care.

Alternatives to 99mTc-sestamibi and 99mTc-tetrofosmin for perfusion imaging include 201Tl for SPECT imaging and 82Rb or 13NH3 for positron emission tomography (PET) imaging (4;5). MPI using 201Tl has similar diagnostic accuracy but image interpretation is more difficult due to greater scatter and attenuation. Moreover, the patient effective radiation dose for MPI using a standard injected dose of 3.5mCi of 201Tl is \~20 mSv. This radiation dose is twice that of 99mTc tracers which typically deliver an effective dose of \~10 mSv. PET imaging with 82Rb or 13NH3 is another alternative, but is much more expensive and not routinely available in Canada due to a very limited install base of PET scanners and associated cyclotrons. The number of SPECT cameras operational in Canada is more than 40 times the number of PET scanners.

Eligibility criteria: Inclusion Criteria:

* Consecutive patients presenting for clinically indicated SPECT perfusion scan
* Patients presenting to sites with a functional CZT camera. Available sites are Ottawa (OHI), Mississauga, and Calgary.
* Age \>18 years old

Exclusion Criteria:

* Patients with a life expectancy less than 1 year, from non cardiac cause
* Age \< 18 years old or lack of consent
* Allergy or contraindication to dipyridamole
* Refractory angina or infarction or need for urgent angiography
* Known pregnancy
* Uncontrolled atrial fibrillation

Primary outcomes:
measure: Rate of non-fatal infarction or death in the normal group of SPECT-Light acquisitions versus standard SPECT acquisitions
timeFrame: 2 years
Secondary outcomes:
measure: Comparison of classification of the degree of abnormality based on the two image acquisition protocols
timeFrame: 2 years
Other outcomes:
Locations:
city: Ottawa
country: Canada
facility: University of Ottawa Heart Institute
state: Ontario
Study officials:
affiliation: Ottawa Heart Institute Research Corporation
name: Renée Hessian, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Hachamovitch R, Hayes SW, Friedman JD, Cohen I, Berman DS. Stress myocardial perfusion single-photon emission computed tomography is clinically effective and cost effective in risk stratification of patients with a high likelihood of coronary artery disease (CAD) but no known CAD. J Am Coll Cardiol. 2004 Jan 21;43(2):200-8. doi: 10.1016/j.jacc.2003.07.043.
citation: Marcassa C, Bax JJ, Bengel F, Hesse B, Petersen CL, Reyes E, Underwood R; European Council of Nuclear Cardiology (ECNC); European Society of Cardiology Working Group 5 (Nuclear Cardiology and Cardiac CT); European Association of Nuclear Medicine Cardiovascular Committee. Clinical value, cost-effectiveness, and safety of myocardial perfusion scintigraphy: a position statement. Eur Heart J. 2008 Feb;29(4):557-63. doi: 10.1093/eurheartj/ehm607. Epub 2008 Jan 17.
citation: Beanlands RS, Chow BJ, Dick A, Friedrich MG, Gulenchyn KY, Kiess M, Leong-Poi H, Miller RM, Nichol G, Freeman M, Bogaty P, Honos G, Hudon G, Wisenberg G, Van Berkom J, Williams K, Yoshinaga K, Graham J; Canadian Cardiovascular Society; Canadian Association of Radiologists; Canadian Association of Nuclear Medicine; Canadian Nuclear Cardiology Society; Canadian Society of Cardiac Magnetic Resonance. CCS/CAR/CANM/CNCS/CanSCMR joint position statement on advanced noninvasive cardiac imaging using positron emission tomography, magnetic resonance imaging and multidetector computed tomographic angiography in the diagnosis and evaluation of ischemic heart disease--executive summary. Can J Cardiol. 2007 Feb;23(2):107-19. doi: 10.1016/s0828-282x(07)70730-4.