Is Attenuation Correction for Myocardial Perfusion Imaging Underutilized?

Abstract

Myocardial SPECT remains an important diagnostic technique in patients suspected of significant coronary artery disease. However, the diagnostic accuracy is hampered by several clinical and technical difficulties. Among these, soft tissue attenuation is one of the most frequent causes. Attenuation correction has the power to correct for these artifacts, increasing the diagnostic accuracy of myocardial SPECT. The current review summarizes the available clinical evidence for attenuation correction and raises the question if this technique is not underutilized in current clinical practice.

You might be correct, but it makes no difference: No impact of attenuation correction for SPECT MPI on downstream testing

“…Although diagnostic accuracy is relatively high for SPECT MPI in this intermediate group (sensitivity 85-90%, specificity 70-75%), the technique can be hampered by several clinical and technical factors. [2][3][4] An estimated 17-49% of all SPECT MPI scans will present with some form of artifact-and among these, soft tissue attenuation is one of the most frequent and carries the specific risk of a falsepositive result, particularly in obese patients. 2,[5][6][7] Attenuation correction (AC) is a process by which photons absorbed by the combination of photoelectric and scatter effects in the patient can somehow be compensated for.…”

“…[2][3][4] An estimated 17-49% of all SPECT MPI scans will present with some form of artifact-and among these, soft tissue attenuation is one of the most frequent and carries the specific risk of a falsepositive result, particularly in obese patients. 2,[5][6][7] Attenuation correction (AC) is a process by which photons absorbed by the combination of photoelectric and scatter effects in the patient can somehow be compensated for. 7 Usually, a transmission scan is used (with sealed radioactive source, X-ray, or CT) to measure attenuation coefficients along the thorax which are then used to mathematically correct for soft tissue absorption.…”

“…The most common finding in prior clinical studies investigating AC in SPECT MPI, is that it significantly improves the normalcy rate and specificity for detecting CAD. 2,7 Broadly, the weight of evidence across several studies is considered to favor its use, leading to the joint position statement of the American Society of Nuclear Cardiology and Society of Nuclear Medicine recommending AC implementation into daily care; and it is considered a rapidly evolving standard for SPECT MPI. 8 However, within that statement it is also suggested that both non-corrected and corrected image datasets are still reviewed and integrated into the final report-at least until the reader gains appropriate experience and confidence in the specific AC methodology in use.…”