Angiography Suite Cone-Beam Computed Tomography Perfusion Imaging in Large-Vessel Occlusion Patients Using RAPID Software: A Pilot Study
- Other version(s) of this article
You are viewing the most recent version of this article. Previous versions:
Multidetector computed tomography (CT) perfusion (MDCTP) volume estimation using RAPID software (iSchemaView, Menlo Park, CA) has been validated in clinical trials for endovascular thrombectomy (EVT) selection.1,2 The availability of cone-beam CT perfusion (CBCTP) in the angiosuite might shorten workflow times in late-window patients transferred from primary centers without CTP capabilities. We evaluate whether quantitative analysis of MDCTP and CBCTP using RAPID software would lead to comparable ischemic core and hypoperfused tissue volumes in patients undergoing EVT.
Methods
Anonymized data are available upon reasonable request. This single-center study was approved by our Institutional Review Board and all participants/proxies signed a written informed consent form. We conducted a prospective, single-arm interventional study including patients with anterior circulation large-vessel occlusion stroke eligible for EVT. MDCTP and CBCTP datasets were processed using RAPID software (Data Supplement).
Ischemic core was defined as relative cerebral blood flow of <30% on MDCTP and <45% on CBCTP of the corresponding contralateral territory. The hypoperfused tissue was evaluated using time-to-maximum >6.0 s and time-to-maximum >10.0 s thresholds. We compared MDCTP and CBCTP volumes using intraclass correlation coefficient, Bland-Altman agreement plots, and Pearson and Spearman correlations. Finally, we compared CBCTP ischemic core and the final infarct volume in reperfused patients.
Results
Thirteen patients were included in the final analysis (Figure I and Table I in the Data Supplement). We found a strong correlation between MDCTP and CBCTP for the ischemic core (Pearson=0.91, Spearman=0.87) and time-to-maximum >6.0 s (Pearson=0.90, Spearman=0.85). Bland-Altman analysis showed 92% agreement for both perfusion parameters (Figure). We observed an intraclass correlation coefficient of 0.89 (95% CI, 0.67–0.96) for the ischemic core and 0.86 (95% CI, 0.55–0.96) for time-to-maximum >6.0 s (Table II in the Data Supplement).

Figure. Ischemic core and hypoperfused tissue analysis. Scatterplot with regression line of relative cerebral blood flow (CBF) (A) and time-to-maximum (Tmax) >6.0 s (C) from multidetector computed tomography (CT) perfusion (MDCTP) and cone-beam CT perfusion (CBCTP). Bland-Altman plots comparing CBF (B) and Tmax>6.0 s (D) between MDCTP and CBCTP. Scatterplot with regression line and Bland-Altman plot comparing CBCTP ischemic core and final infarct volume in successful reperfusion patients. FIV indicates final infarct volume; and TICI, Thrombolysis in Cerebral Infarction.
Comparing CBCTP ischemic core and the final infarct volume, we found a strong correlation (Pearson=0.87, Spearman=0.87) and 90% of agreement. We also observed an intraclass correlation coefficient of 0.81 (95% CI, 0.48–0.94).
Discussion
This study demonstrates that automated analysis of ischemic core and hypoperfused tissue volumes derived from MDCTP and CBCTP in patients with stroke eligible for EVT provides comparable results.
In our study, the contrast dose received in CBCTP after MDCTP was relatively low, and the median time between studies was short, which could reduce perfusion variations between modalities. Potential infarct growth between modalities was considered and 91% (10/11) of cases had concordant results using the DEFUSE 3 trial (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke) eligibility criteria for EVT.2
An automated real-time perfusion volumetric processing in the angiosuite would allow bypassing the emergency department for transferred large-vessel occlusion late-window patients. Thus, this technology might reduce reperfusion times and improve patients’ functional outcomes. In addition, CBCTP images could provide a more accurate assessment of perfusion parameters during and immediately after EVT. Downsides of transferring patients from primary centers to angiosuite might include EVT ineligibility due to large core infarct, low stroke severity, distal occlusion, among others.3
The study is limited by the small sample size. Additional limitations are included in the Data Supplement.
CBCTP | cone-beam CT perfusion |
CT | computed tomography |
EVT | endovascular thrombectomy |
MDCTP | multidetector CT perfusion |
Sources of Funding
This study has been funded by an investigator-initiated grant from iSchemaView.
Supplemental Materials
Expanded Methods, Results, and Discussion
Online Figure I
Online Tables I and II
Disclosures Dr Ortega-Gutierrez is consultant for Medtronic and Stryker. Dr Albers is consultant for Genentech, and ownership interest and consultant on the advisory board for iSchema View. Dr Schafer is employee of Siemens Healthineers. The other authors report no conflicts.
Footnotes
References
- 1.
Albers GW, Goyal M, Jahan R, Bonafe A, Diener HC, Levy EI, Pereira VM, Cognard C, Cohen DJ, Hacke W, . Ischemic core and hypoperfusion volumes predict infarct size in SWIFT PRIME.Ann Neurol. 2016; 79:76–89. doi: 10.1002/ana.24543CrossrefMedlineGoogle Scholar - 2.
Albers GW, Marks MP, Kemp S, Christensen S, Tsai JP, Ortega-Gutierrez S, McTaggart RA, Torbey MT, Kim-Tenser M, Leslie-Mazwi T, ; DEFUSE 3 Investigators. Thrombectomy for stroke at 6 to 16 hours with selection by perfusion imaging.N Engl J Med. 2018; 378:708–718. doi: 10.1056/NEJMoa1713973CrossrefMedlineGoogle Scholar - 3.
Reddy ST, Savitz SI, Friedman E, Arevalo O, Zhang J, Ankrom C, Trevino A, Tzu-Ching W . Patients transferred within a telestroke network for large-vessel occlusion [published online September 20, 2020].J Telemed Telecare. 2020. doi: 1357633X20957894Google Scholar