Novel flat-panel cone-beam CT compared to multi-detector CT for assessment of acute ischemic stroke: A prospective study

Abstract

Cone beam CT (CBCT) imaging assessment of acute ischemic stroke (AIS) patients with large-vessel occlusion (LVO) in the angiosuite may improve stroke workflow and decrease time to recanalization. In order for this workflow to gain widespread acceptance, current CBCT imaging needs further development to improve image quality. Our study aimed to compare the image quality of a new CBCT protocol performed directly in the angiosuite with imaging from multidetector CT as a gold standard. Methods: AIS patients with an LVO who were candidates for endovascular treatment were prospectively included in this study. Following conventional multidetector CT (MDCT), patients underwent unenhanced cone beam CT (XperCT, Philips) imaging in the angiosuite, using two different protocols: a standard 20.8 s XperCT and/or an improved 10.4 s XperCT protocol. Images were evaluated using both qualitative and quantitative methods. Results: We included 65 patients in the study. Patients received CBCT imaging prior to endovascular treatment; 18 patients were assessed with a standard 20.8 s protocol scans and 47 with a newer 10.4 s scan. The quantitative analysis showed that the mean contrast-to-noise ratio (CNR) was significantly higher for the newer 10.4 s protocol compared with the 20.8 s protocol (2.08 +/-0.64 vs. 1.15 +/-0.27, p < 0.004) and the mean image noise was significantly lower for the 10.4 s XperCTs when compared with the 20.8 s XperCTs (6.30 +/-1.34 vs. 7.82 +/-2.03, p=<0.003). Qualitative analysis, including 6 measures of image quality, demonstrated that 74.1 % of the 10.4 s XperCT scans were ranked as 'Acceptable' for assessing parenchymal imaging in AIS patients(scoring 3-5 points on a 5-point Likert-scale), compared with 32.4 % of the standard 20.8 s XperCT and 100 % of the MDCT scans. Compared to the MDCT studies, 83 % of the 10.4 s XperCT scans were deemed sufficient image quality for a direct-to-angiosuite selection, compared to only 11 % for the standard 20.8 s scans. The largest image quality improvements included grey/white matter differentiation (59 % improvement), and reduction of image noise and artefacts (63 % & 50 % improvement, respectively). Conclusions: Continued advances in cone-beam CT allow marked improvements in image quality for the assessment of brain parenchyma, which supports a direct-to-angiosuite approach for AIS patients eligible for thrombectomy treatment.

Principles, techniques and applications of high resolution cone beam CT angiography in the neuroangio suite

“…Traditional utilizations of non-contrast CBCT, either before the thrombectomy as a substitute of the traditional CT scanner or during/after the thrombectomy to rule out a hemorrhage, are very well detailed elsewhere. 22 The roles of HR-CBCT angiography during stroke thrombectomy are infrequent. They include the evaluation of collaterals 23 or the visualization of vessels distally to a point of occlusion, through an acquisition obtained during intra-arterial injection from the ascending aorta.…”

Performance characterization of a prototype dual‐layer cone‐beam computed tomography system

“…[1][2][3][4] However, due to a number of factors including X-ray scatter, beam hardening artifacts, and detector limitations, conventional flat detector systems currently provide limited discrimination between low contrast tissues,such as white and gray matter in the brain. 1,5 Furthermore, conventional CBCT is limited to imaging with full energy spectrum integration and cannot be used to estimate effective atomic number or electron density (ED) within different tissues. Atomic number and ED can be used to differentiate between tissues and are of interest both in diagnostic radiology and for radiotherapy planning.…”

The butterfly effect: improving brain cone-beam CT image artifacts for stroke assessment using a novel dual-axis trajectory

“…We have noticed an improvement in overall quality of cone-beam CT over the past few years. First, shorter acquisition times accompanied by higher doses and advanced postprocessing were shown to improve image noise, artifacts, and gray/white matter differentiation for circular scans 5. Although there have been many improvements since the first maxillofacial examination in 1994, CBCT image quality could be further improved by increasing the radiation dose.…”

“…Studies have shown that CBCT imaging is reliable for hemorrhage characterization,1 2 which can be of great value during long or complex procedures where bleeding risks are high, such as arteriovenous malformation or fistula embolizations. Detection of ischemic lesions using CBCT is also possible,3–5 which has supported a sparked interest towards using this technology in patients presenting with acute ischemic stroke (AIS). Ideally CBCT could be used for treatment triage of patients with AIS and hopefully used to bypass the need for conventional CT to bring patients directly to the angiography suite for mechanical thrombectomy.…”

“…Despite recent protocol improvements to incorporate advanced reconstruction algorithms,5 8 9 CBCT image quality is still limited by various image artifacts, which contribute to a loss of anatomical information 1 3 5. Image artifacts, such as streaks, image distortion, or contrast inhomogeneity, can arise from various physics-based or patient-based sources like beam hardening or metallic artifacts 10 11.…”