Preliminary clinical study of LDCTP and ULDCTP combined with IMR in the diagnosis of cerebral stroke
Abstract
Part one. Asssing the image quality of low-do CT
cerebral perfusion imaging combined with IMR Objective To investigate the feasibility of low-do CT examination combined with IMR in cerebral CT perfusion (CTP) imaging.
Materials and Methods Patients with clinical suspicion of cerebral infarction underwent the cerebral CTP imaging were enrolled in this study. 60 patients who had normal CTP imaging in one of cerebral hemispheres were divided into group A (30 cas, 80Kv-150mAs with FBP reconstruction) and group B (30 cas, 80Kv-30mAs with FBP, iDo44, IMR1, IMR2, IMR3 reconstruntion respectively). At the level of the most superior margin of the ganglionic structures (ASPECTS 2), quantitative and qualitative analysis of CTP images was performed by one radiologist. And CTDIvol, DLP was recorded and effective do (ED) was calculated. CT and SD values, SNR, CNR, perfusion parameters (CBV, CBF, MTT, TTP), subjective CTP imaging scores were compared among 6 reconstruction ts using ANOV A or Kruskal Wallis test.
Results ①. CT and SD values at grey matter (GM) and white matter (WM) were significantly higher and the SNR, CNR were significantly lower between group A and group B reconstructed with FBP and iDo44 (P<0.05). All of subjective CTP imaging scores with FBP and iDo44 were 0 in group B. ②. There was no statistical significance in CT and SD values, SNR, CNR, and subjective CTP imaging scores between group A and group B reconstructed with IMR1 (P>0.05). The CT values of GM, SD values of GM and WM were significantly lower, SNR, CNR of of the GM and WM were significantly higher between group A and group B reconstructed with IMR2, IMR3 (P<0.05). ③. There was no statistical significance in the perfusion parameters at ROIs of GM and WM between group A and group B reconstructed with iDo44, IMR1, IMR2, IMR3 and groupA (P>0.05). ④. The ED in group B was 0.50mSv, decread by 80% compared to ED in
group A which was 2.52mSv.
Conclusion There are stable perfusion parameters, stable imaging quality and lower radiation do using LDCTP (80Kv-30mAs) examination combined with IMR. It is considerd that LDCTP could become a routine cerebral CTP method.
Keywords computed tomography, perfusion imaging, low radiation do, cerebral, IMR, image quality.
Part two.Preliminary clinical study of ULDCTP combined
with IMR in the diagnosis of cerebral stroke
Objective To investigate the clinical application of ultra-low-do CT Perfusion (ULDCTP) examination combined with IMR in the diagnosis of cerebral stroke.
Materials and Methods 95 patients with clinical suspicion of ischemic stroke who underwent the cerebral CT perfusion imaging and MRI within 3 days were enrolled in this study. The patients were divided into group A (45 cas, 80Kv-30mAs with IMR2 reconstruction) and group B (50 cas, 80Kv-10mAs with IMR2 reconstruction). The relative normal perfusion imaging at ASPECT2 level were chon for quantitative and qualitative analysis. CTDIvol, DLP was recorded and effective do (ED) was calculated in each ca. CT and SD values, SNR, CNR, perfusion parameters (CBV, CBF, MTT and TTP), subjective CTP imaging scores were compared respectively between two groups by using Independent-Samples T test or Mann-Whitney U test depending on the homogeneity of variance. The detection rate of different size of cerebral infarcts on CTP imaging was also compared in two groups.
Results ①. Subjective CTP imaging scores in group A and group B was were high and moderate an
d the Kappa were 0.70 and 0.51 respectively. ②.There was no statistical significance in CT values of GM and WM between two groups (P>0.05). SD values in group B were larger than tho in group A (P<0.05). SNR and CNR in group B was smaller than that in group A (P<0.05). ③. There was no statistical significance in the CBV of the GM and WM, MTT of the GM and TTP of the GM and WM between two groups (P>0.05). There was statistical significance in the CBF of GM and WM and MTT of WM between two groups (P<0.05). ④. The detection rate of lacunars, focal and massive ischemic cerebral infarctions in group A was 4.44%, 100%, 100%, tho in group B was 4.00%, 100%, 100%, respectively. ⑤. The ED in group A and group B was 0.50mSv,
0.17mSv. ⑥. "Concentric circles" and "black holes" artifacts at CTP images were en obviously in group B.
Conclusion The characteristics of ULDCTP using 80Kv-10mAs with IMR were ultralow radiation, fair CTP imaging quality, and more imaging artifacts, et al. But focal and massive cerebral infarction could be diagnod bad on ULDCTP imaging.
Keywords ULDCTP, cerebral, IMR, perfusion imaging, detection rate, ischemic infarction
序组成语
小狗素描Written by: Zhang Yun
党员民主自评Supervid by: Gong Jianping
低剂量及极低剂量脑CT灌注成像联合全模型迭代重建算法在脑卒中诊断中的初步临床研究
目录
前言 (1)
参考文献 (4)
第一部分低剂量脑CT灌注成像联合IMR的图像质量评价 (8)赤西西比
人生感悟诗词
材料与方法 (8)
结果 (11)
讨论 (16)
参考文献 (20)
第二部分极低剂量脑CTP联合IMR在脑卒中诊断中的初步临床研究 (23)
孕妇能吃坚果吗
材料与方法 (23)英语chant
结果 (25)
讨论 (28)
参考文献 (31)
病例展示 (32)
结论 (35)
综述 (36)
参考文献 (41)
攻读学位期间公开发表的论文 (44)
中英文缩略词表 (45)
空调制热多少度合适
致谢 (46)
低剂量及极低剂量脑CT灌注成像联合全模型迭代重建算法在脑卒中诊断中的初步临床研究 前 言
前言
中国第三次全国死因调查报告指出，脑血管疾病已成为我国人口死亡的首因，并且脑卒中的发病率在以每年8.7%的速度增长[1]。在1990-2015年期间，因缺血性和出血性脑卒中的伤残调整寿命年(disability-adjusted life-years, DALYs)逐年增加。2015年，脑卒中是导致全球DALYs的第二大原因，是导致中国DALYs的首要原因，已经成为中国医疗支出及经济的重大负担[2-4]。急性缺血性脑卒中（Acute Ischemic Stroke, AIS）是最常见的脑卒中类型，约占全部脑卒中的60％～80％[4-7]。
对AIS患者而言，再灌注治疗的时间窗确定至关重要，CT灌注成像（CTP）能确定超急性期脑梗死核心和缺血半暗带的范围，在最短时间内明确临床诊断和制定治疗方案，打破时间窗的限制，降低病人的死亡率及致残率，预测并监测病人预后[8-15]，CTP在诊断急性缺血性脑梗死及指导临床制定治疗方案方面起着越来越重要的作用。
虽然脑CTP在AIS病人诊断中具有许多优势，但其最大的缺陷就是辐射剂量过高。CTP需对感兴趣区(几个层面或全脑)进行连续反复扫描，使得患者接受X射线辐射剂量较常规CT检查显著增加。2009年，美国FDA公布的X线剂量安全报告中指出：AIS病人脑CTP检查的X线辐射剂量超过头颅CT平扫的8倍之多[16]。针对脑CTP检查辐射剂量过高的问题，美国FDA建议使用多个不同的解决方案，并极力
主张基于ALARA原则（As Low As Reasonably Achievable Principal），以最低的辐射剂量获取符合诊断要求的CTP图像[16]。
因此，为使脑CTP成像更加广泛地应用于临床，降低X射线辐射剂量已成为CTP 领域亟待解决的关键性课题。CTP的辐射剂量主要与管电压、管电流、采集时间及采集频率有关。
依靠减少扫描总时间及增加扫描时间间隔来降低辐射剂量的作用有限[17-19]。降低管电压是一种有效方法，Fang XK等[20-21]将CTP的管电压从80Kv降低到70Kv，相应的X线辐射剂量降低了34.8%，同时能保持灌注图像的稳定性。降低管电流也是降低CTP辐射剂量的方法，但降低过多会导致CT灌注值出现偏差[22]，低管电流所产生的图像噪声和伪影会直接影响各灌注参数计算的准确性极有可能导致误诊[23, 24]。
传统滤波反投影算法（filtered back projection, FBP）过去被作为CT图像重建算
