How serious a problem for myocardial perfusion assessment is moderate misregistration between SPECT and CT?
✍ Scribed by Kenneth J. Nichols
- Publisher
- Springer
- Year
- 2007
- Tongue
- English
- Weight
- 51 KB
- Volume
- 14
- Category
- Article
- ISSN
- 1071-3581
No coin nor oath required. For personal study only.
✦ Synopsis
See related article, p. 200
This issue of the Journal includes an article documenting the prevalence of misregistration between myocardial perfusion single photon emission computed tomography (SPECT) images and single-slice computed tomography (CT) transaxial images used as attenuation correction maps. 1 The authors report that there was "moderate" or "severe" misregistration between the 2 scans in 42% of patients. Of these, 3.6% (2/55) were judged as having severe misregistration. At first glance, this would be alarming to clinicians, who would be concerned that the implication is that they would be in danger of incorrectly reporting moderate myocardial perfusion defects in 30% to 40% of patients, where there are none, as a result of moderate misregistration.
It would certainly be a pernicious situation for clinicians to invest the extra time and money needed to perform CT attenuation correction only to have this mislead them and increase their false-positive rate, given that they have been reading myocardial perfusion scans successfully for decades without CT attenuation correction, for which acceptable true-negative and false-positive rates are the norm. Myocardial perfusion assessment is the single most frequently performed nuclear cardiology procedure, and it was inevitable that considerable effort was expended to enable attenuation correction to aid in this assessment, for both quantitative and visual analyses. There now are several options available to physicians in terms of the equipment to perform attenuation correction. Originally, only scanning radioactive line sources were available, but subsequent phantom studies showed that the best results were obtained via CT scanners. 2 These now include CT scanners that are significantly slower than From the