The Application Value Of 3D T₂ Star Weighted Angiography In Ischemic Infarction

Objective:To explore the application value of three dimensional T2 star weighted angiography(3D SWAN) in ischemic infarction.Methods:40 patients with ischemic infarction(3h-7d) underwent T1WI, T2WI, DWI,3D MRA and 3D SWAN.20 patients had been follow up MRI after treatment, there were 60 man-time MR scan in total. Among these patients,40 man-time had DSC-PWI,58 man-time had T2*WI. (1)The hemorrhagic transformation(HT) and cerebral microbleeds(CMBs) of ischemic infarction on T1WI/T2WI, T2*WI and 3D SWAN were calculated. (2) The MCA susceptibility hypointensity sign on 3D SWAN and MCA stenosis/occlusion sign on 3D MRA were observed and compared, there changes after treatment were followed up. (3) The small vessles change on 3D SWAN and the perfusion manifestation on DSC-PWI were evaluated.Results:(1) In 58 man-time cerebral infarction cases, T1WI/T2WI, T2*WI and 3D SWAN had deteced 11,16 and 23 HT cases respectively, the HT detection rate was 19%,28% and 40% respectively. There was a significant difference between the HT detection rate of these three sequences after statistical analysis (P<0.05). In 58 man-time cerebral infarction cases, T1WI/T2WI showed no CMBs, SWAN found more cases of HT and CMBs than T2*WI,There was a significant difference after statistical analysis (P<0.05). Among the 18 CMBs cases which the 3D SWAN had ditected,7 of them had HT, the HT rate was 39%.(2) In 60 man-time cerebral infarction cases,16 man-time cases had MCA stenosis/occlusion sign on 3D MRA,14 of them had MCA susceptibility hypointensity sign on 3D SWAN. Among them,4 cases of the MCA susceptibility hypointensity sign disappeared/decreased on 3D SWAN and the occlusive arteries recanalized on follow up MR scan after treatment for about 1 week.44 man-time cases without the MCA stenosis/occlusion sign on 3D MRA also didn't have MCA susceptibility hypointensity sign on 3D SWAN. There was a significant difference after statistical analysis (P＜0.05).(3) 1.In the 39 cases of PWI, there were 26 small vessles became more, thick and black, among them, there were 19 had collateral circulation,1 had reperfusion,3 had hyperperfusion,3 had hypoperfusion on PWI; 2. In the 39 cases, there were 13 small vessles became less, thin and light, among the 13 cases,9 had hypoperfusion,3 had collateral circulation,1 had reperfusion on PWI. After the chi square test, there was a statistical difference between the small vessles change and the perfusion manifestation around the infarction lesion.Conclusion:(1) It's more sensitive of 3D SWAN to detect HT and CMBs than T2*WI and T1WI/T2WI.(2) There is a good relevance between MCA susceptibility sign on 3D SWAN and the MCA stenosis/occlusion sign on 3D MRA.3D SWAN can not only ditect the thrombus in the stem of MCA, but also the small thrombus in the distal of MCA.(3) The small vessle changes around the infarction lesion on 3D SWAN indirectly reflect the perfusion manifestation. The small vessles become more, thick and black correlated with collatral circulations, and the small vessles are less, thin and light correlated with hypoperfusion.