使用频率选择性非线性融合技术的非增强CT检测早期缺血性水肿的准确性
Accuracy of Non-Enhanced CT in Detecting Early Ischemic Edema Using Frequency Selective Non-Linear Blending.
作者信息
Bier Georg, Bongers Malte N, Ditt Hendrik, Bender Benjamin, Ernemann Ulrike, Horger Marius
机构信息
Department of Diagnostic and Interventional Radiology, Eberhard Karls-University Tuebingen, D-72076, Tuebingen, Germany.
Siemens AG Healthcare, Imaging & Therapy Systems Computed Tomography & Radiation Oncology, Siemensstr. 1, D-91301, Forchheim, Germany.
出版信息
PLoS One. 2016 Jan 25;11(1):e0147378. doi: 10.1371/journal.pone.0147378. eCollection 2016.
PURPOSE
Ischemic brain edema is subtle and hard to detect by computed tomography within the first hours of stroke onset. We hypothesize that non-enhanced CT (NECT) post-processing with frequency-selective non-linear blending ("best contrast"/BC) increases its accuracy in detecting edema and irreversible tissue damage (infarction).
METHODS
We retrospectively analyzed the NECT scans of 76 consecutive patients with ischemic stroke (exclusively middle cerebral artery territory-MCA) before and after post-processing with BC both at baseline before reperfusion therapy and at follow-up (5.73±12.74 days after stroke onset) using the Alberta Stroke Program Early CT Score (ASPECTS). We assessed the differences in ASPECTS between unprocessed and post-processed images and calculated sensitivity, specificity, and predictive values of baseline NECT using follow-up CT serving as reference standard for brain infarction.
RESULTS
NECT detected brain tissue hypoattenuation in 35 of 76 patients (46.1%). This number increased to 71 patients (93.4%) after post-processing with BC. Follow-up NECT confirmed brain infarctions in 65 patients (85.5%; p = 0.012). Post-processing increased the sensitivity of NECT for brain infarction from 35/65 (54%) to 65/65 (100%), decreased its specificity from 11/11 (100%) to 7/11 (64%), its positive predictive value (PPV) from 35/35 (100%) to 65/69 (94%) and increased its accuracy 46/76 (61%) to 72/76 (95%).
CONCLUSIONS
This post-hoc analysis suggests that post-processing of NECT with BC may increase its sensitivity for ischemic brain damage significantly.
目的
缺血性脑水肿较为隐匿，在卒中发作后的最初数小时内难以通过计算机断层扫描检测到。我们推测，采用频率选择性非线性融合（“最佳对比度”/BC）的非增强CT（NECT）后处理可提高其检测水肿和不可逆组织损伤（梗死）的准确性。
方法
我们回顾性分析了76例连续性缺血性卒中患者（均为大脑中动脉供血区-MCA）在再灌注治疗前基线期以及随访期（卒中发作后5.73±12.74天）使用阿尔伯塔卒中项目早期CT评分（ASPECTS）对NECT扫描图像进行BC后处理前后的情况。我们评估了未处理图像和后处理图像之间ASPECTS的差异，并以随访期CT作为脑梗死的参考标准，计算基线NECT的敏感性、特异性和预测值。
结果
NECT在76例患者中的35例（46.1%）检测到脑组织低密度影。经BC后处理后，这一数字增加到71例患者（93.4%）。随访期NECT证实65例患者（85.5%；p = 0.012）发生脑梗死。后处理使NECT对脑梗死的敏感性从35/65（54%）提高到65/65（100%），特异性从11/11（100%）降低到7/11（64%），阳性预测值（PPV）从35/35（100%）降低到65/69（94%），准确性从46/76（61%）提高到72/76（95%）。
结论
这项事后分析表明，NECT采用BC后处理可能会显著提高其对缺血性脑损伤的敏感性。
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