Aviv R I, Mandelcorn J, Chakraborty S, Gladstone D, Malham S, Tomlinson G, Fox A J, Symons S
Division of Neuroradiology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
AJNR Am J Neuroradiol. 2007 Nov-Dec;28(10):1975-80. doi: 10.3174/ajnr.A0689. Epub 2007 Oct 5.
Qualitative CT perfusion (CTP) assessment by using the Alberta Stroke Program Early CT Score (ASPECTS) allows rapid calculation of infarct extent for middle cerebral artery infarcts. Published thresholds exist for noncontrast CT (NCCT) ASPECTS, which may distinguish outcome/complication risk, but early ischemic signs are difficult to detect. We hypothesized that different ASPECTS thresholds exist for CTP parameters versus NCCT and that these may be superior at predicting clinical and radiologic outcome in the acute setting.
Thirty-six baseline acute stroke NCCT and CTP studies within 3 hours of symptoms were blindly reviewed by 3 neuroradiologists, and ASPECTS were assigned. Treatment response was defined as major neurologic improvement when a > or =8-point National Institutes of Health Stroke Scale improvement at 24 hours occurred. Follow-up NCCT ASPECTS and 90-day modified Rankin score (mRS) were radiologic and clinical reference standards. Receiver operating characteristic curves derived optimal thresholds for outcome.
Cerebral blood volume and NCCT ASPECTS had similar radiologic correlations (0.6 and 0.5, respectively) and best predicted infarct size in the absence of major neurologic improvement. A NCCT ASPECT threshold of 7 and a cerebral blood volume threshold of 8 discriminated patients with poor follow-up scans (P < .0002 and P = .0001) and mRS < or =2 (P = .001 and P < .001). Only cerebral blood volume predicted major neurologic improvement (P = .02). Interobserver agreement was substantial (intraclass correlation coefficient, 0.69). Cerebral blood volume ASPECTS sensitivity, specificity, positive predictive value, and negative predictive value for clinical outcome were 60%, 100%, 100%, and 45%, respectively. No patients with cerebral blood volume ASPECTS <8 achieved good clinical outcome.
Cerebral blood volume ASPECTS is equivalent to NCCT for predicting radiologic outcome but may have an additional benefit in predicting patients with major neurologic improvement.
使用阿尔伯塔卒中项目早期CT评分（ASPECTS）进行定性CT灌注（CTP）评估，可快速计算大脑中动脉梗死的梗死范围。非增强CT（NCCT）的ASPECTS已公布了阈值，其可能区分预后/并发症风险，但早期缺血征象难以检测。我们推测CTP参数与NCCT的ASPECTS阈值不同，且这些阈值在预测急性情况下的临床和影像学预后方面可能更具优势。
3名神经放射科医生对36例症状出现3小时内的基线急性卒中NCCT和CTP研究进行盲法评估，并给出ASPECTS评分。治疗反应定义为24小时时美国国立卫生研究院卒中量表改善≥8分的显著神经功能改善。随访NCCT的ASPECTS和90天改良Rankin量表评分（mRS）为影像学和临床参考标准。通过受试者操作特征曲线得出预后的最佳阈值。
脑血容量和NCCT的ASPECTS具有相似的影像学相关性（分别为0.6和0.5），并且在无显著神经功能改善的情况下对梗死大小的预测最佳。NCCT的ASPECTS阈值为7，脑血容量阈值为8时，可区分随访扫描结果不佳（P <.0002和P =.0001）以及mRS≤2（P =.001和P <.001）的患者。只有脑血容量可预测显著神经功能改善（P =.02）。观察者间一致性良好（组内相关系数为0.69）。脑血容量ASPECTS对临床预后的敏感性、特异性、阳性预测值和阴性预测值分别为60%、100%、100%和45%。脑血容量ASPECTS <8的患者均未获得良好的临床预后。
脑血容量ASPECTS在预测影像学预后方面与NCCT相当，但在预测有显著神经功能改善的患者方面可能具有额外优势。
