| Objective:To investigate a fast way to access infarct core and ischemic penumbra by using whole brain CT Perfusion (CTP) parameters, including cerebral blood flow (CBF), mean transit time (MTT) and their-relative values rCBF and rMTT.Methods:31 patients suspected acute ischemic stroke (AIS) in the First Affiliated Hospital of Chongqing Medical University from October 2013 to September 2014 underwent CTP combined with head-neck CT angiography (CTA). CTP maps including average imaging, CBF, MTT and CTA maps were analysed. The infarct core was defined obviously decreased in CBF, Ischemia area was defined as MTT increased apparently, ischemic penumbra was defined as abnormal area of CBF/MTT did not match. All the patients completed Magnetic Resonance Imaging (MRI) examination in 3 days after CTP examination. The high intensity in diffusion weighted imaging (DWI) were diagnosed as infarct core. CBF and DWI were compared to evaluate the sensitivity and specificity of CBF diagnosing infarction. The time from the start of examination of whole brain CTP combined with head and Neck CTA to the end of the images post-processing was recorded. The size, the location and the number of infarct cores in CTP average, CBF, MTT image and DWI were recorded. Compare CBF with DWI to assess the consistence when diagnosing infarct cores. The values of CBF and MTT, together with their relative values were noted by two researchers respectively and independently. Choosing rMTT> 145% as the standard to assess the CBF/MTT’s accuracy when diagnosing ischemic penumbra.Result:Of the 31 patients, CTP detected 24 cases with infarction and 5 cases negative, with a total 47 infarct lesions,43 lesions were diagnosed by CTP average image,33 lesions were diagnosed by CBF.10 patients were diagnosed with penumbra by MTT/CBF did not match, there were 19 penumbra. The number of penumbra which rMTT> 145% was 16, and rMTT< 145% was 3. CTA displayed 5 cases with completely occlusion and 7 cases with moderate to severe stenosis. Whole brain CTP combined with head and neck CTA examination and post-processing cost 27.00±2.12 mins.26 cases were diagnosed with acute ischemic stroke by MRI with 97 lesions. The relevancy and consistency of the location and the size about infarction in DWI data and CBF data made a good consistence (t=1.87, P=0.07). The sensitivity and specificity of CBF detected infarction core were 92.30% and 100%, but CBF found only 34.02% of the total infarct cores. The size of the infarction got in DWI was smaller than that in CBF except the corpus callosum and bilateral semi-oval center. When turns to infarct core, the mean value of CBF and MTT were 3.38±1.87ml·100g-1·min-1,20.07±4.56s, the rCBF and rMTT were 0.33±0.13,2.33±0.51, respectively. When turns to ischemic penumbra, the mean value of CBF and MTT were 6.79±1.29 ml·100g-1·min-1, 17.07±3.13s, the rCBF was 0.71±0.09,and rMTT was 1.53±0.19. When choosing rMTT> 145% as the standard for defining ischemic penumbra, the method CBF/MTT did not match had a accuracy of 84.21%.Conclusion:The size and location of infarct core in CBF consisted well with DWI, but when turns to the number of infarct core CBF had a poor ability against DWI. When choosing CTP parameters to evaluate the ischemia, the rMTT was consistent well with the prevailing view----rMTT >145%, and can be used to assess ischemia. With the application of whole brain CT Perfusion combined with head and neck CTA, we can get comprehensive information of the responsibility of the blood providing vessels, the infarct core and penumbra all at one examination and also at a fast and an accurate way. |
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