Summary of an article in Swedish medical journal: Läkartidningen, issue 43, 2008
Authors:
BIRGITTA JANEROT-SJÖBERG, över- läkare, docent, fysiologiska kliniken, Hjärtcentrum, Univer- sitetssjukhuset i Linköping birgitta.janerot.sjoberg@lio.se
REIDAR WINTER, överläkare, med dr, fysiolog- och kardiologklini- kerna, Karolinska Universitets- sjukhuset Huddinge
JAN ENGVALL, överläkare, docent, fysiologiska kliniken, Hjärtcentrum, Universitets- sjukhuset i Linköping
LARS-ÅKE BRODIN, professor i medicinsk teknik, överläkare, Kungliga Tekniska Högskolan (KTH), Stockholm; fysiologiska kliniken, Karolinska Universitets- sjukhuset Huddinge
Ectomography & myocardial scintigraphy
According to SBU (34), isotopebased methods displaying myocardial perfusion, provide the best prognostical information in the case of cardiovascular desease. Myocardial scintigraphy performed on a resting patient in an acute situation during chest pains in a previously healthy patient without arteriosclerosis, has a negative predictive value for acute coronary syndrom of >99 percent(36). It is cost effective (37) and has been recommended in American guidelines and since 2008 also in Swedish national guidelines (1).
Its negative, predictive value for coronary events per year, is 99 percent, even for a stable coronary artery desease. A Danish study proves that the method is suitable as a triage tool even for in the case of stable coronary artery desease. The study included patients undergoing coronary angiography (38). Despite good diagnostic and prognostic results only 2 percent of patients with coronary artery desease undergo myocardial scintigraphy compared to 50 - 70 percent in the USA (34).
A recently completed masters thesis in the Medtech Institutions at the Karolinska Institute and the Royal Institute of Technology in Stockholm, has demonstrated that, using an isotopebased method as a gate-keeper in the emergency ward at the Karolinska Hospital in Huddinge, would save between 20 and 70 MSEK per year.
The access in Sweden today is generally quite poor and limited to office hours. In an on-going research project, a mobile gamma camera (ectomograph) is being built enabling isotopebased examinations in a bedside setting on patients with acute chest pains. Through a combination of good hardware and innovative iterative collection and reconstructive algorithms (39-41), the system can recreate an image of cerebral or coronary vascularization in 2,5 to 3 minutes. The images have been compared to state of the art SPECT-systems in almost 800 patients and provides equivalent information to the stationary SPECT-gamma camera, which has a collection and recreation time of 20 minutes or more (42). We therefore believe that this system is a way to transform cardiovascular examinations from an anatomical approach to a more functional based dignostic approach.
Sources:
[1]Socialstyrelsen S. Nationella riktlinjer för hjärtsjukvård 2008: Beslutsstöd för prioriteringar. In: Socialstyrelsen, editor., 2008
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[36]Klocke FJ, Baird MG, Lorell BH, Bateman TM, Messer JV, Berman DS, et al. ACC/AHA/ASNC guidelines for the clinical use of cardiac radionuclide imaging--executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASNC Committee to Revise the 1995 Guidelines for the Clinical Use of Cardiac Radionuclide Imaging). Circulation. 2003;108 (11):1404-18.
[37]Mowatt G, Vale L, Brazzelli M, Hernandez R, Murray A, Scott N, et al. Systematic review of the effectiveness and cost-effectiveness, and economic evaluation, of myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction. Health Technol Assess 2004;8 (30:iii-iv):1-207.
(38]Hoilund-Carlsen PF, Johansen A, Christensen HW, Vach W, Moldrup M, Bartram P, et al. Potential impact of myocardial perfusion scintigraphy as gatekeeper for invasive examination and treatment in patients with stable angina pectoris: observational study without post-test referral bias. Eur Heart J. 2006;27 (1):29-34. Epub 2005 Sep 23.
[39]Dale s. Ectomography - Theory and implementation in gamma camera imaging. Ph.D. Thesis at Karolinska Institute. Stockholm, 1989.
[40]Persson M. Development of a mobile tomographic gamma camera based om ectomography. Stockholm: Karolinska Institute, 2001.
[41]Valastyan I. Application of tomographic imaging in nuclear medicine. Kungliga tekniska högskolan. Stockholm: Stockholm University, 2006.
[42]Dale SM, Bone DE, Brodin LA, Lindstrom C. Comparison of SPECT and ectomography for evaluating myocardial perfusion with technetium-99m-sestamibi. J Nucl Med. 1997;38 (5):754-9.