The Combined Study Of CT Perfusion Imaging With CTAngiography In The Diagnosis Of Transient Ischemic Attack

Objective: This study conducted by CT perfusion imaging (CTPI) and CT angiography (CTA) was to investigate the cerebral vascular stenosis in TIA patients. To explore the value of CTPI and CTA in the diagnosis of TIA, and the relationship between clinical manifestation and radiological findings of TIA was discussed, and then further explore the etiology, pathogenesis of TIA so as to guide the treatment of TIA, by means of making the treatments individually to improve the therapeutic results.Methods: 37 patients with TIA admitted in NO.1 Hospital attach to Dalian Medical University during 2007.4-2008.1 were enrolled into the study. All patients were diagnosed TIA according to the revised diagnostic criteria .A detailed history was investigated by asking the TIA patients and the NIHSS score was noted according to the situation of TIA onset.The data would be transmitted to the workstation, and processed by CT perfusion image software, then CBF, CBV,MTT image maps were obtained. Based on CT perfusion imaging, the stages of TIA were demonstrated as follows: (Ⅰ) MTT were delayed, CBF was normal, and CBV was normal or slightly increased;(Ⅱa) MTT were delayed, CBF was decreased, and CBV was normal or slightly decreased; (Ⅱb) MTT were delayed, CBF and CBV were decreased. As CTA completed, CTA software help us get CTA graph, which was about the location and severity of the vascular stenosis would be noted in details.Statistical Methods: Quantitative data analyzed by t-test analysis, qualitative data analyzed by chi-square test. Results:1. In 37 cases checked by both CTA and CTPI, there were 28 cases (75.7%) with perfusion abnormalities, and I period were 7 cases(23.3%),the average ratio of CBF,CBV and MTT were 1.00,1.01 and 1.02;II1 period were 2 cases(6.7%), the average ratio of rCBF,rCBV and rMTT were 0.84,0.96,1.35; IIb period were 2 cases(6.7%), the average ratio of rCBF, rCBV and rMTT were 0.75.0.85,1.42.2 The relation of abnormality in CTPI and the clinical manifestation of TIA:2.1 Cerebral hypoperfusion correlated with increased NIHSS score in TIA patients. The positive rate (91.7%) in NIHSS≥4 group during TIA onset was significantly higher than the NIHSS<4 group (66.7%). (χ2=5.003,p=0.024)2.2 Cerebral hypoperfusion correlated with different frequency of TIA onset. The more frequency of TIA attacked, the more obvious the severity of ischemia in CTPI. (χ2=4.852,p=0.038)3 In 37 cases checked by both CTA and CTPI, there were 25cases (67.6%) with convict vascular stenosis and perfusion abnormalities,VA were 20cases(80%) and BA were 5 cases (20%).4 The relationship between CTPI positive rate and the convict stenosis: In 37 cases checked by both CTA and CTPI, there were 23 cases (67.6%) with convict vascular stenosis and perfusion abnormalities, which were matched with clinical symptoms. There were 5 cases (13.5%) with perfusion abnormalities but without convict vascular stenosis. Through statistical analysis, there was a significant difference between them. It suggested that the positive rate of CTPI were higher in the cases with convict vascular stenosis.5 The correspondence relationship between CTPI and CTA abnormality had the following 4 types. It suggested that the theory of hypoperfusion was the common cause of TIA.5.1 There were 25 cases (67.6%) with convict vascular stenosis accompanied by perfusion abnormalities.5.2 There were 3cases (8.1%) with perfusion abnormalities in CTPI but without convict vascular stenosis in CTA. All of them conduct DWI inspection and none of them revealed new infarction in DWI.5.3 There were 4 cases (10.8%) with convict vascular stenosis in CTA but without perfusion abnormalities in CTPI.5.4 There were 5 cases (13.5%) neither had convict vascular stenosis nor had perfusion abnormalities, and none of them had new infarction in DWI.Conclusions:1 CTPI combined with CTA had a high sensitivity for the diagnosis of TIA. They can be used as the imaging basis of TIA diagnosis.2 There were still cerebral blood flow abnormalities in CTPI though the symptoms of TIA had alleviated. The application of CTPI and CTA can help to study the etiology, pathogenesis mechanism of TIA, to verify the hypo perfusion theory of TIA, to guide the treatment selection of patients with TIA. It can be used to provide reliable support and nuro image basis for TIA anticoagulant, anti-platelet aggregation and bloon and stent.3 The study showed that the CTPI positive rate was higher in TIA patients with convict vascular stenosis, in addition, CTPI positive rate was still had relation to TIA clinical manifestation.It had a more important clinical value to advance of the imaging study from infarction to TIA.