Low-Radiation-Dose Stress Myocardial Perfusion Measurement Using First-Pass Analysis Dynamic Computed Tomography

Abstract

Objectives: The aim of this study was to assess the feasibility of a prospective first-pass analysis (FPA) dynamic computed tomography (CT) perfusion technique for accurate low-radiation-dose global stress perfusion measurement. Materials and Methods: The prospective FPA technique was evaluated in 10 swine (42 ± 12 kg) by direct comparison to a previously validated retrospective FPA technique. Of the 10 swine, 3 had intermediate stenoses with fractional flow reserve severities of 0.70 to 0.90. In each swine, contrast and saline were injected peripherally followed by dynamic volume scanning with a 320-slice CT scanner. Specifically, for the reference standard retrospective FPA technique, volume scans were acquired continuously at 100 kVp and 200 mA over 15 to 20 seconds, followed by systematic selection of only 2 volume scans for global perfusion measurement. For the prospective FPA technique, only 2 volume scans were acquired at 100 kVp and 50 mA for global perfusion measurement. All prospective global stress perfusion measurements were then compared with the corresponding reference standard retrospective global stress perfusion measurements through regression analysis. The CTDI 32 vol and size-specific dose estimate of the prospective FPA technique were also determined. Results: All prospective global stress perfusion measurements (P PRO ) at 50 mA were in good agreement with the reference standard retrospective global stress perfusion measurements (P REF ) at 200 mA (P PRO = 1.07 P REF −0.09, r = 0.94; root-mean-square error = 0.30 mL/min per gram). The CTDI 32 vol and size-specific dose estimate of the prospective FPA technique were 2.3 and 3.7 mGy, respectively. Conclusions: Accurate low-radiation-dose global stress perfusion measurement is feasible using a prospective FPA dynamic CT perfusion technique.

Combining perfusion and angiography with a low-dose cardiac CT technique: a preliminary investigation in a swine model

“…The low-dose cardiac CT technique was shown to enable accurate, vessel-specific rest perfusion, stress perfusion, and CFR measurement, with simultaneously acquired co-registered CTA data using only four volume scans and two contrast injections, respectively, where such a protocol had not been fully realized by our prior work [ 18 – 21 ]. Hence, the present work is valuable as it fully demonstrates the potential for substantial radiation and contrast dose reduction in comprehensive CT-based assessment of CAD.…”

“…Of the twelve animals, three had sub-occlusive balloon stenosis in the left anterior descending (LAD) coronary artery. Of additional note, the stress data from eight of the twelve animals (including the three with stenosis) were used in a prior study [ 21 ]. Each animal was prospectively imaged with the low-dose cardiac CT technique.…”

“…The low-dose cardiac CT technique was shown to enable accurate, vessel-specific rest perfusion, stress perfusion, and CFR measurement, with simultaneously acquired coregistered CTA data using only four volume scans and two contrast injections, respectively, where such a protocol had not been fully realized by our prior work [18][19][20][21].…”

“…Nevertheless, despite these data, accurate, vessel-specific stress perfusion, CFR, and CTA measurement remained to be combined and validated as a true low-dose cardiac CT technique. Hence, the purpose of this study was to assess the accuracy of a new low-dose cardiac CT technique, using our previously validated retrospective technique as the reference standard for perfusion measurement [18][19][20][21]. The central hypothesis was that accurate, low-dose, vessel-specific rest perfusion, stress perfusion, and CFR measurement is feasible, with simultaneously acquired co-registered CTA data, using a total of only four volume scans and two contrast injections.…”

“…Next, we retrospectively developed this technique in a swine model of ischemic coronary artery disease, validating vessel-specific [ 18 ] perfusion measurement as compared with invasive fractional flow reserve (FFR) and quantitative microsphere perfusion measurement, respectively [ 19 , 20 ]. Finally, we determined that accurate retrospective and prospective assessment of global stress perfusion is feasible at a tube current as low as 50 mA [ 21 ]. Nevertheless, despite these data, accurate, vessel-specific stress perfusion, CFR, and CTA measurement remained to be combined and validated as a true low-dose cardiac CT technique.…”