Cerebral CT Perfusion Using an Interventional C-Arm Imaging System: Cerebral Blood Flow Measurements

Abstract

BACKGROUND AND PURPOSE CTP imaging in the interventional suite could reduce delays to the start of image-guided interventions and help determine the treatment progress and end point. However, C-arms rotate slower than clinical CT scanners, making CTP challenging. We developed a cerebral CTP protocol for C-arm CBCT and evaluated it in an animal study. MATERIALS AND METHODS Five anesthetized swine were imaged by using C-arm CBCT and conventional CT. The C-arm rotates in 4.3 seconds plus a 1.25-second turnaround, compared with 0.5 seconds for clinical CT. Each C-arm scan had 6 continuous bidirectional sweeps. Multiple scans each with a different delay to the start of an aortic arch iodinated contrast injection and a novel image reconstruction algorithm were used to increase temporal resolution. Three different scan sets (consisting of 6, 3, or 2 scans) and 3 injection protocols (3-mL/s 100%, 3-mL/s 67%, and 6-mL/s 50% contrast concentration) were studied. CBF maps for each scan set and injection were generated. The concordance and Pearson correlation coefficients (ρ and r) were calculated to determine the injection providing the best match between the following: the left and right hemispheres, and CT and C-arm CBCT. RESULTS The highest ρ and r values (both 0.92) for the left and right hemispheres were obtained by using the 6-mL 50% iodinated contrast concentration injection. The same injection gave the best match for CT and C-arm CBCT for the 6-scan set (ρ = 0.77, r = 0.89). Some of the 3-scan and 2-scan protocols provided matches similar to those in CT. CONCLUSIONS This study demonstrated that C-arm CBCT can produce CBF maps that correlate well with those from CTP.

A Novel Technique for the Measurement of CBF and CBV with Robot-Arm-Mounted Flat Panel CT in a Large-Animal Model

“…27 Moreover, our focus was to find out whether assessment of dynamic perfusion parameters was feasible in a new large-animal model. However, quantification is possible as was demonstrated by Ganguly et al 13 They stated that CBF measured with C-arm cone beam CT correlated well with that from CTP, but in this work, multiple injections and multiple acquisitions were performed to overcome the temporal resolution limits of the C-arm system, whereas we chose a protocol with a single injection and only 1 fill run. Third, we chose sheep for our experiments because the technique of surgical occlusion was described and sheep have a larger, gyrencephalic brain, as opposed to that in most other animal stroke models.…”

“…Several experimental and clinical studies have demonstrated that measurement of CBV is feasible by using C-arm CT. [10][11][12] More recently, CBF was measured in healthy swine and canines with such a system. 13,14 We report our experience using a modified C-arm system to measure steady-state CBV and also to make dynamic measurements of CBF in an experimental sheep stroke model.…”

Dynamic Angiography and Perfusion Imaging Using Flat Detector CT in the Angiography Suite: A Pilot Study in Patients with Acute Middle Cerebral Artery Occlusions

“…However, recent studies in canines and swine models have now demonstrated the feasibility of dynamic perfusion imaging with the use of a flat detector angiographic system. [10][11][12] The aim of this pilot study was to test the feasibility of this novel application by comparing FD-CTP and FD-CTA with a multimodal MR imaging protocol in patients with acute ischemic stroke. Additionally, the effective patient dose was evaluated.…”

“…11 Briefly, before the start of the contrast injection, 1 forward and 1 reverse highspeed baseline scan (rotation) were performed to obtain a baseline set of nonenhanced (mask) images. Five seconds after the start of the peripheral contrast injection, a bidirectional series of 7 high-speed FD-CT rotational acquisitions was initiated.…”

“…The basic reconstruction represents a modified version of the algorithm reported previously, which uses the widely accepted deconvolution approach to calculate the dynamic perfusion parameters. 11,12 The arterial input function was manually selected at the anterior cerebral artery. We reconstructed all parameters maps (eg, TTP, MTT, CBV, and CBF) by using a 5-mm section thickness and spacing.…”