Controversy in nuclear cardiologyAttenuation correction in cardiac SPECT: The boy who cried wolf?
Section snippets
Diagnostic Accuracy: Visual
The key clinical promise of AC is its potential to increase the diagnostic accuracy of coronary artery disease detection by improving image quality and reducing attenuation artifacts, as well as perhaps helping better identify multivessel disease.8 Over the last decade, several published studies have reported an increase in the diagnostic accuracy (through higher specificity) for the detection of coronary artery disease when SPECT MPI is attenuation-corrected.13, 14, 15, 16, 17, 18, 19 However,
Uniformity of Results
There is little dispute that the world of AC is a very fractionated one,26 mainly because, as already mentioned, camera companies made AC a differentiating element early on in their marketing strategy. It is fair to say that no two hardware setups for emission-transmission AC were based on the same geometry,27 and the number (as well as manner of implementation) of software corrections associated with AC was also plentiful. An article by O’Connor et al,10 published in 2002, showed just how
Additional Costs
The additional costs associated with the use of AC can be divided into fixed costs (hardware/software) and variable costs (transmission sources). Adding an AC device to a SPECT camera can often exceed $60,000 in cost,8 which is in turn still less expensive than the incremental cost of a hybrid SPECT/CT system over a SPECT camera. Transmission sources typically need to be replaced at regular intervals at additional expense (in excess of $10,000/y for gadolinium line sources), lest the quality of
Is AC the only way to achieve the desired result?
Proponents of AC have argued that even though AC may be costly, its use should lead to an overall decrease in the cost of patient care, mainly through the reduction in referrals for cardiac catheterization.8 However, this hypothesis “is not supported by current literature,”8 and the argument itself loses its strength if alternative approaches to AC can achieve the same or similar results at a much lesser cost.
Conclusion
We would like to stress that we do not necessarily consider AC for SPECT MPI to be unfeasible or unworthy of scientific pursuit; indeed, a great deal of creative scientific effort has been poured into this area of investigation over the past 3 decades, and much of it has contributed to a better understanding of the physics, as well as the clinical aspects, of our field. However, the great variety of available AC hardware and software “flavors,” the historical pattern of commercial release of
Acknowledgment
The authors receive royalties from Cedars-Sinai Medical Center for algorithms incorporated in commercially distributed software that performs automatic quantification of perfusion, function, and other cardiac parameters. The software can be applied to both attenuation-corrected and nonattenuation-corrected images.
References (53)
- et al.
Attenuation compensation for cardiac single-photon emission computed tomographic imaging: part 1Impact of attenuation and methods of estimating attenuation maps
J Nucl Cardiol
(1995) - et al.
Attenuation compensation for cardiac single-photon emission computed tomographic imaging: part 2Attenuation compensation algorithms
J Nucl Cardiol
(1996) - et al.
Attenuation correction in cardiac positron emission tomography and single-photon emission computed tomography
J Nucl Cardiol
(1995) - et al.
A multicenter evaluation of commercial attenuation compensation techniques in cardiac SPECT using phantom models
J Nucl Cardiol
(2002) - et al.
American Society of Nuclear Cardiology and Society of Nuclear Medicine joint position statement: attenuation correction of myocardial perfusion SPECT scintigraphy
J Nucl Cardiol
(2004) - et al.
Combined corrections for attenuation, depth-dependent blur, and motion in cardiac SPECT: a multicenter trial
J Nucl Cardiol
(2000) - et al.
Attenuation correction and gating synergistically improve the diagnostic accuracy of myocardial perfusion SPECT
J Nucl Cardiol
(2002) - et al.
Value of attenuation correction on ECG-gated SPECT myocardial perfusion imaging related to body mass index
J Nucl Cardiol
(2005) - et al.
Clinical validation of SPECT attenuation correction using x-ray computed tomography–derived attenuation maps: multicenter clinical trial with angiographic correlation
J Nucl Cardiol
(2005) - et al.
Quantitative Tc-99m attenuation-corrected sestamibi SPECT: development and multicenter trial validation of myocardial perfusion stress gender-independent normal database in an obese population
J Nucl Cardiol
(2004)