Signature Analysis Of Diffusion-weighted Imaging And CT Angiography In TIA

Objective: To study the relation of TIA patients'clinical risk score (ABCD²) and clinical features to the diffusion-weighted imaging(positive DWI), the apparent diffusion coefficient(ADC), exponential apparent diffusion coefficient(EADC), relative apparent diffusion coefficient(rAI_ADC) and elative exponential apparent diffusion coefficient(rAI_EADC)and discuss the significance of DWI and ADC in the treatment of TIA patients ; to analyse the clinical influencing factor of the characteristic of CT long coverage angiography(CTA) and MR diffusion weighted imaging(DWI) in TIA patients.Materials and Methods:1. The patients with TIA admitted to neurology department and emergency department in Tangshan Gongren Hospital between February 2009 and September 2010 were consecutively studied. All patients underwent routine MRI, DWI and CT long coverage angiography. DWI was performed within 24 hours after symptoms onset and CTA was performed within 3 days after symptoms onset.2. A detailed history of TIA patients was investigated.The ABCD² score was noted according to the situation of TIA onset,then a schedule table of TIA patient's condition and the data of 7 days follow up was written.3. Patients with TIA were examined by 1.5T Signa MR and DWI,including sagittal view T₁WI, cross-sectional view T₁WI, T₂WI and FLAIR.The scanning parameter was T₁WI:SE sequence TR440ms, TE8ms; T₂WI:FSE sequence TR 4000ms,TE 99ms; FLAIR TR 10000 ms, TE 140 ms, TI 2200 ms.The b value of DWI were 0 and 1000 respectively.4.Those patients with informed consent who were not allergic to iodine underwent CT long coverage angiography.The whole check was performed with GE Light-Speed-16 spiral computed tomograph scanner or the Phillip Brilliance 64 spiral computed tomograph scanner with patients backlying on the examination couch. The enhanced CT scanning was performed with non-ionic contrast Agent(300～370mgl/ml),and the total amount was 100 to 200ml. The contrast agent was injected into the vein of upper extremity by high-pressure syringe with speed of 3.0～4.0ml/s. Scanning qualification: The votage was 120kv, active current 100 mAs, matrix 512×512,and the distance between layers 0.375mm. The scanning extent is from aortic arch to calvaria.5.The ADC, EADC, rAI_ADC and rAI_EADC were calculated by an image analyzing system to analyze whether the identification of acute ischemic lesions (positive DWI) or the above index was related to the presence of clinical features and clinical risk scores. The clinical and imaging analyses were performed to those who were excuted CTA examination.The degree and distribution of stenosis of cranial and cervical arteries of the patients with different clinical risk score and prognosis were observed.6.All the clinical and imaging data were evaluated and diagnosed by two experts,and the approaches were blind and double blind methods. When there was different opinion they would reach consensus through consultation,and reserve the images.7.Statistical analysis: Quantitative data was analyzed by independent-sample t-test, chi-square test or rank sum test. SPSS 17.0 statistical analysis software was used to deal with the data and the results were regarded as significance when p<0.05.Results:1. A total of 87 cases (54males and 33 females) were enrolled in the research, including 60 carotid system TIA cases and 38 vertebrobasilar system TIA cases. The ages range from 35 to 83, and the average age was 57.7±11.7 years old. 62 TIA patients undertook the intracranial and cervical CTA within 3 days after symptoms onset, including carotid system TIA 42 cases and vertebrobasilar system TIA 20 cases.2. The Clinical typing of TIA and the positive rate of DWI. 39 out of 87 TIA patients (44.8%) revealed focal abnormalities on DWI; 33 out of 60 cases with carotid system TIA (55.0%) were found acute ischemic lesions on DWI; 6 out of 27 cases with vertebrobasilar system TIA (22.2%) were found acute ischemic lesions on DWI. There was difference between the two groups (χ²=8.921 ,p=0.003).That prompted the DWI postive rate of carotid system TIA was higher than that of vertebrobasilar system TIA.3. The relationship between the clinical features and the postive rate of DWI.The clinical situation and risk factors eg. age, sex ,blood pressure, the duration of symptoms, diabetes mellitus, limb weakness, speech impairment and sensory disturbance did not relate to the positive rate of DWI, neither did the ABCD² scores (p<0.05). However facial palsy did relate to the positive rate of DWI.4. The clinical influencing factor of the metered parameter on ADC map in the TIA patients who could be found acute ischemic lesions on DWI.The study shows that the TIA patients whose ABCD² scores were above four or whose age was above 60 or who was accompany with hypertension, the ADC value, EADC value of the acute ischemic leisions were markedly lower than those who were not, and the EADC value and rEADC value were much higher. The rADC value (t=-2.350 p=0.032)and rEADC value (t=2.412 p=0.028) of speech impairment group differed from those of non-speech impairment group.5. The segment ,degree of stenosis of cranial and cervical arteries of TIA patients whose clinical Clinical typing was different.The segment, degree and distribution of stenosis of cranial and cervical arteries of the carotid system TIA and vertebrobasilar system TIA patients.There was difference between the two groups. The mezzo stenosis or occlusion rate of responsible arteries of carotid system TIA patients was higher than that of vertebrobasilar system TIA patients.6. The relationship between the stenosis of cranial and cervical arteries and the age, sex of TIA patients.The fantasy stenosis rate of cranial and cervical arteries of TIA patients whose age was greater than or equal to 60 was higher than those whose age was smaller than 60 and the above rate of male patients was higher than that of female patients.7. The relationship between the vascular risk factor and the stenosis of the intracranial and cervical vascular.The rate of mezzo stenosis, fantasy stenosis or occlusion was increase in the TIA patients who were accompany with hypertension or hyperlipemia.8. The relationship between the clinical situation and the intracranial and cervical angiostegnosis.There is no significent difference between the groups which based on one limb weakness, speech impairment, and facial palsy (p>0.05).9. The relationship between the ABCD² score and the stenosis of intracranial and cervical vascular.The fantasy stenosis or occlusion rate of intracranial and cervical arteries of TIA patients whose ABCD² score was higher than or equal to 4 was higher than those whose ABCD² score was smaller than 4. There was significant difference(p<0.05).10. The prognosis within 7 days and the intracranial and cervical angiostegnosis.The stenosis and occlusion of arteries increased in the patients who were attacked by cerebral infarction within 7 days(p<0.05).Conclusions:1. DWI of Those patients with facial palsy were likely to be positive,but facial palsy did not relate to the diffusion restrained degree of hydrone. Performing a DWI, masuring and calculating the ADC, EADC, rAI_ADC and rAI_EADC may add prognostic information to clinical risk scores. Moreover, they could help the doctor diagnose and treat the TIA patients.2. Those patients with high ABCD² scores were likely to be attacked by cerebral infarction. The stenosis and occlusion rate of responsible arteries of the TIA patients who were attacked by cerebral infarction was higher than that of those who were not. The stenosis of vascular may be the major cause of brain ischemia. The application of DWI and long coverage CTA could help to study the etiology, pathogenesis mechanism of TIA, to determine the clinical type of TIA, to guide the treatment selection of the TIA patients. It can be used to provide reliable support and nuroimage basis for the early treatment of TIA patients.3. It could be found in the study that the stenosis and occlusion of intracranial arteries were more than those of cervical arteries. The stenosis and occlusion of carotid system TIA patients was different from that of vertebrobasilar system TIA patients. The clinicians should think highly of carotid system TIA and treat the patients early in order to prevent cerebral infarction.4. The higher the ABCD² score was, the longer the duration of symptoms was. The TIA patients who could be found stenosis and occlusion of arteries were prone to be found acute ischemic lesions on DWI, and were prone to be attacked by stroke. Therefore, we should execute early treatment to TIA patients. It had more important value to advance of the imaging study from infarction to TIA.5. The TIA patients who accompany with age greater than or Equal to 60,the duration of symptoms short, hypertension or hyperlipemia were more likely to be found stenosis or occlusion, which have some referenced value to the clinical therapy and prognosis of TIA.