Cardiovascular Nuclear Imaging: Balancing Proven Clinical Value and Potential Radiation Risk

Abstract

1162 Objectives In 1925 Blumgart demonstrated that he could measure serial blood levels of isotope activity to determine cardiac contractility through the measurement of “circulation time.” Todays modern SPECT cameras replace the cloud chambers of Blumgarts era, allowing us the opportunity to measure serial changes in isotope concentration needed to measure ischemia. This study determines the clinical utility of Blumgarts method using todays SPECT camera. Methods One hundred twenty individuals underwent diagnostic study measuring changes in sestamibi activity in eight regions of interest (ROIs) using a SPECT camera. Subjects were stressed and using Blumgarts method of measuring isotope scintillations, serial measurements were compared in each of the eight regions with results found on coronary angiography. Results Parabolic regression of stenosis from coronary angiography (figure 1) on changes in isotope activity were compared for each of the vascular territories. The result yielded an effect size of R(95%)=0.72 to 0.95, p=3.8x10-8. Conclusions Prior investigations suggested that changes in isotope distribution over time could be employed to more accurately measure ischemia. A thorough literature search and investigation and application of Blumgarts method of serial measurements of isotope scintillation, when applied using todays SPECT camera reveals that changes in sestamibi distribution can be accurately measured, allowing clinicians to employee SPECT cameras to obtain angiographic results, while improving diagnostic accuracy and reducing patient radiation exposure. Research Support CVISM sponsored