PURPOSE Computed tomography (CT) perfusion (CTP) source images contain both brain perfusion and cerebrovascular information, and may allow a dynamic assessment of collaterals. The purpose of the study was to compare the image quality and the collaterals identified on multiphase CT angiography (CTA) derived from CTP datasets (hereafter called CTPA) reconstructed with iterative model reconstruction (IMR) algorithm in patients with middle cerebral artery (MCA) steno-occlusion with those of routine CTA. METHODS Consecutive patients with a unilateral MCA steno-occlusion underwent non-contrast CT (NCCT), CTP, and CTA. CTPA images were reconstructed from CTP datasets. The vascular attenuation, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of routine CTA and CTPA were measured and analyzed by Student's t test. Subjective image quality and collaterals were scored and compared using the Wilcoxon signed-rank test. RESULTS Fifty-eight patients (mean age 61.7 years, 78% males, median National Institutes of Health Stroke Scale score = 12) were included. The effective radiation dose of CTP was 1.28 mSv. The vascular attenuation, SNR, CNR, and the image quality of CTPA were considerably higher than that of CTA (all, p < 0.001). Collaterals were rated higher on CTPA compared with CTA (1.79 ± 0.64 vs. 1.22 ± 0.84, p < 0.001). Fifty-three percent of patients with poor collaterals assessed on single-phase CTA had good collaterals on CTPA. CONCLUSION CTPA derived from CTP datasets reconstructed with IMR algorithm offers image quality comparable to routine CTA and provides time-resolved evaluation of collaterals in patients with MCA ischemic disease.

中文翻译：

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从脑中动脉狭窄患者的CT灌注数据得出的超低剂量多相CT血管造影。

目的计算机断层扫描（CT）灌注（CTP）源图像既包含脑灌注信息，又包含脑血管信息，并且可能允许对侧支进行动态评估。本研究的目的是比较采用迭代模型重建（IMR）算法重建的CTP数据集（以下称为CTPA）的多相CT血管造影（CTA）所识别的图像质量和在大脑中动脉（MCA）狭窄患者中的侧支-与常规CTA一起使用。方法对单侧MCA狭窄闭塞的连续患者进行非对比CT（NCCT），CTP和CTA。从CTP数据集重建CTPA图像。常规CTA和CTPA的血管衰减，图像噪声，信噪比（SNR）和对比噪声比（CNR）均通过Student t检验进行了测量和分析。使用Wilcoxon符号秩检验对主观图像质量和附带材料进行评分和比较。结果纳入了58名患者（平均年龄61.7岁，男性78％，美国国立卫生研究院卒中量表评分中位数= 12）。CTP的有效辐射剂量为1.28 mSv。CTPA的血管衰减，SNR，CNR和图像质量显着高于CTA（所有，p <0.001）。与CTA相比，CTPA上的抵押品评级更高（1.79±0.64对1.22±0.84，p <0.001）。单期CTA评估的抵押品不良患者中有53％的CTPA抵押品良好。结论从IMR算法重建的CTP数据集获得的CTPA提供的图像质量可与常规CTA相比，并能对MCA缺血性疾病患者的侧支进行时间分辨评估。