Clinical value of stress-only Tc-99m SPECT imaging: Importance of attenuation correction

• Published in: Journal of nuclear cardiology 2013-02, Vol.20 (1), p.27-37
• Main Authors: Mathur, Shishir, Heller, Gary V., Bateman, Timothy M., Ruffin, Richard, Yekta, Arshad, Katten, Deborah, Alluri, Nitya, Ahlberg, Alan W.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Attenuation correction; Cardiology; Coronary Artery Disease - diagnosis; Coronary Artery Disease - diagnostic imaging; Decision Support Systems, Clinical; Exercise Test; Female; Follow-Up Studies; Humans; Image Processing, Computer-Assisted; Imaging; Male; Medicine; Medicine & Public Health; Middle Aged; myocardial perfusion imaging; Myocardial Perfusion Imaging - methods; Nuclear Medicine; Original Article; Radiology; Signal Processing, Computer-Assisted; SPECT; stress-only; Technetium Tc 99m Sestamibi; Tomography, Emission-Computed, Single-Photon - methods
• ISSN: 1071-3581; 1532-6551
• DOI: 10.1007/s12350-012-9633-7

In selected patients, stress-only SPECT imaging has been proposed as an alternative to rest-stress SPECT imaging to improve laboratory efficiency and reduce radiation exposure. The impact of attenuation correction (AC) upon interpretation, post-test patient management and cardiac risk stratification in relation to stress-only imaging is not well understood. The purpose of this study was to determine the clinical value for laboratory throughput and predicting outcomes of normal and abnormal stress-only SPECT imaging with AC in a consecutive series of clinically referred patients. A retrospective analysis of 1,383 consecutive patients who were scheduled for stress-only SPECT imaging for symptom assessment of suspected myocardial ischemia was performed. All images had been interpreted and categorized using the standard 17-segment model without AC followed by AC. Follow-up data for 2.1 ± 1.3 years after SPECT imaging for the occurrence of cardiac events (non-fatal MI, cardiac death, and cardiac revascularization) previously collected by routine methods were reviewed. Non-AC SPECT image interpretation revealed that 58% (802/1383) of patients had abnormal stress images. AC image interpretation of the abnormal non-AC images re-classified 83% (666/802) of these as normal. Among patients with abnormal stress images after AC (136/1383), 63% (86/136) returned for additional rest scans, while the remaining 37% (50/136) were clinically managed without further rest images. The incidence of cardiac death or non-fatal MI was very low in patients with normal stress-only scans (0.7%). A strategy of stress-only imaging with AC in symptomatic patients is an efficient method which appropriately identifies at risk and low-risk patients yielding a low percentage requiring rest imaging. Clinical decisions can be made based on abnormal stress-only imaging without further rest imaging if clinically appropriate.