FLAIR High Signal Understanding And Assessment Of Infarction

Objective: To discuss the variation of FLAIR imaging sequence in the different staging of cerebral infarction,and understand the pathophysiology of cerebral infarction progress., and to assess the significance of FLAIR signal intensity change according to the clinical situation of the cerebral infarction, improving the prognosis level of cerebral infarction; And to assess the diagnostic value of FLAIR imaging sequence,DWI sequences and T2WI imaging sequence for accurate staging of the cerebral infarction.Methods: Retrospective analysis clinical data and image data of 168 cases of patients with different periods of cerebral infarction, and observing the different periods of cerebral lesions'signal intensity, shape, location, extent, borders and circumstances surrounding the lesion, etc, and followed-up the changes of the patients of clinical symptoms and signs; Obserbving the infarct size and scope of the FLAIR images, T2WI images and DWI image, usingχ2 test to detect the sensitivity and visibility of lesions between the three sequences; Using Friedman Test to evaluate the size and scope of different periods of cerebral lesions; Multi-angled observate the form of intracranial arterial system form MRA images, and assessment and grading the vascular stenosis, is divided into four grades : such as : 0 grade ,1 grade , 2 grade,3 grade. Applicationχ2 test analysis the relationship between the degree of vascular stenosis and the extent of the lesion size.SPSS13.0 package was Used for data analysis, when P <0.05 considered having significant difference.Results:1 Hypertension, diabetes, coronary heart disease is the risk factors of the ischemic cerebrovascular disease .2 The FLAIR sequence showed the different infarct signal intensity at the different times of cerebral infarction.In the super-acute phase, the lesions'signal was slightly higher, and the signal intensity was uniform , and there were high or moderately high signal; The lesion signal in Sub-acute phase was uneven, mainly is high signal, and partly is medium high signal; Chronic phase,the signal intensity within the lesion reduced from the medium-high signal to slightly high signal,and until it dropped to cerebrospinal fluid signal, or low signal associated with the high signal around.3 In the cases of 168 cases, in which there were 98 cases (58.3%) of well-defined margin, mostly was the lacunar infarction; And there were 70 case (41.7%) of lesion with edges blurred and not sharp,almost all cases of which were large infarction, accompanying by significant mass effect, midline shift, local shallow sulcus gyri and disappeared, and brain swelling.4 The detection rate of patients with cerebral infarction was different in different sequences, such as FLAIR imaging sequence, T2WI sequences and DWI sequence. In super-acute phase, DWI-positive rate was 100%, and the lesions can be detected in FLAIR and T2WI sequences after 4 hours onset of the disease,the positive rates were 36.1%, 11.1% respectively; In acute and subacute phase, the lesions all can be etected in DWI sequences, FLAIR sequences and T2WI sequences, and FLAIR-positive rates was relatively high, up to 75.0%;In chronic phase, FLAIR sequence showed the reduced signal of the lesions, and FLAIR-positive rate was 75.8%.5 The comparation between the largest diameter and area of the lesions at the different check sequence and different times of the cerebral infaction. In Super-acute phase, DWI sequence showed showed the largest diameter of the lesions, which is significantly larger than FLAIR and T2WI sequences. In acute and subacute phase, the three sequences showed basically the same scope of the lesions. In chronic phase, T2WI imaging sequence shows the larger scope of the lesions.6 There are relationship between the artery stenosis and cerebral infarction. When the artery stenosis was severly, the cerebral infarction was larger. 7 There are relationship between the area , stage of the cerebral infarction and patients with neurological deficit. The patients with higher neurological deficit scores when there were larger area of cerebral infarct or super-acute and acute phase of cerebral infarct,and after treatment, the reduction of the neurological deficit was less,and the prognosis was poor.Conclusions:1 The FLAIR sequence showed the different infarct signal intensity at the different times of cerebral infarction.2 There were different detection rate of the cerebral infarction in different MRI sequences.3 FLAIR sequences, DWI sequence, and T2WI sequence showed the different scope of the lesions between the different stages of cerebral infarction.4 The higher grade arterial stenosis, the large area of intracranial cerebral infarction.5 There were a good consistency in detecting occlusive cerebrovascular disease among the conventional MRI sequences, DWI sequences and 3D-TOF MRA, the pathological process of the lesions can be very good evaluated when the multiple sequences were combinated, and can accurately staging the cerebral infarction, and the clinical characteristics of patients was comprehensived,so more information can be provided for the clinical diagnosis and treatment of strategic options.6 Clinically, there are relationship between the area , stage of the cerebral infarction and patients with neurological deficit.