Department of Radiology, Stanford University, California 94305-5488, USA.
AJNR Am J Neuroradiol. 2011 Sep;32(8):1525-31. doi: 10.3174/ajnr.A2518. Epub 2011 Jul 14.
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.
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.
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.
This study demonstrated that C-arm CBCT can produce CBF maps that correlate well with those from CTP.
在介入手术室中进行 CTP 成像可以减少开始图像引导介入的时间延迟，并有助于确定治疗进展和终点。然而，C 臂旋转速度比临床 CT 扫描仪慢，这使得 CTP 具有挑战性。我们为 C 臂 CBCT 开发了一种脑 CTP 方案，并在动物研究中进行了评估。
对 5 只麻醉猪进行 C 臂 CBCT 和常规 CT 成像。C 臂的旋转时间为 4.3 秒加 1.25 秒的往返时间，而临床 CT 的旋转时间为 0.5 秒。每个 C 臂扫描有 6 个连续的双向扫描。使用多个扫描，每个扫描开始时都有不同的延迟，对主动脉弓注入碘造影剂，并使用新的图像重建算法来提高时间分辨率。研究了 3 种不同的扫描集（由 6、3 或 2 次扫描组成）和 3 种注射方案（3ml/s 100%、3ml/s 67%和 6ml/s 50%造影剂浓度）。为每个扫描集和注射生成 CBF 图。计算一致性和 Pearson 相关系数（ρ 和 r），以确定提供以下最佳匹配的注射：左半球和右半球，以及 CT 和 C 臂 CBCT。
使用 6ml 50%碘造影剂浓度注射，左、右半球的 ρ 和 r 值最高（均为 0.92）。对于 6 次扫描集，相同的注射获得了 CT 和 C 臂 CBCT 之间的最佳匹配（ρ=0.77，r=0.89）。一些 3 次扫描和 2 次扫描方案提供了与 CT 相似的匹配。
本研究表明，C 臂 CBCT 可以生成与 CTP 相关性良好的 CBF 图。
