Measuring coronary artery calcification using positron emission tomography-computed tomography attenuation correction images

Abstract

Quantifying CAC using ACCT images appears to be feasible and accurate. In a single cardiac PET examination, information regarding perfusion, LV function, flow quantification, and CAC can be obtained without additional radiation.

Coronary calcium scoring of CT attenuation correction scans: Automatic, manual, or visual?

“…In the same study, the manual method had lower false negative rates of 29% and 35% on rest and stress CTAC. False negative rates were also lower in prior studies evaluating visual and manual CAC scoring methods, being 17% for a manual method by Mylonas et al, 3 and 22% and 25%-30% for visual methods by Einstein et al 4 and Engbers et al, 1 respectively. The automatic method occasionally missed large CAC lesions affected by cardiac motion or partial volume effect resulting in low contrast with the surrounding tissue.…”

“…The ICC between CTAC and CSCT using manual scoring was 0.86-0.87. Mylonas et al 3 reported comparable ICC of 0.80 using a threshold of 130 HU, however, obtained best results using a threshold of 50 HU with ICC of 0.95. Kaster et al 2 found best agreement using a threshold of 110 HU and reported 20% and 5% underestimation of CAC at 130 and 110 HU thresholds.…”

“…The feasibility of this CT attenuation correction (CTAC) scan in identifying and quantifying coronary artery atherosclerotic calcifications has been evaluated in a few studies performed over the last decade, work aiming towards obviating the need for a dedicated coronary artery calcium scoring CT (CSCT), which contributes to study time, cost, and radiation burden. [1][2][3][4] Estimated effective radiation dose from a CSCT varies widely depending on CT protocol, with values around 2 mSv being common, 5 whereas dose from CTAC scan can be as low as 0.3 mSv. 4 In addition, recently published joint guidelines from the Society of Cardiovascular Computed Tomography and the Society of Thoracic Radiology advocate reporting of CAC scores for cardiovascular disease (CVD) risk classification on all non-contrast CT examinations as the appropriate standard of care.…”

“…Two studies 2,3 have focused on manual quantification of CAC from CTAC scans, utilizing commercially available software packages to place regions of interest on structures thought to represent coronary calcification, and determine CAC score with predefined thresholds. Both studies compared Agatston scores from CSCT to CAC score quantified on CTAC images at various attenuation thresholds for calcium.…”

Low-dose 3D 82Rb PET

“…This comprehensive exam could also provide absolute flow data (not used in Kaster et al study, but collected nonetheless as a part of the imaging protocol) as well as CT maps, which could be used for calcium scoring. 9 Incidentally, another benefit from using the lower injected dose could be more reliable absolute flow data, as the initial 82 Rb count rate during 3D PET acquisition may present challenges in accurate measurement of the left ventricular input function for the kinetic analysis.…”