Evaluating Cerebrovascular Using High-resolution Vessel Wall Magnetic Resonance Imaging

The first part:Enhancement of intracranial arteries on contrast-enhanced 3D high-resolution vessel wall magnetic resonance imagingBackground and objective:High-resolution vessel wall magnetic resonance imaging(HR-VW-MRI)has been widely used in the diagnosis of cerebrovascular diseases recently.It can show the vessel wall of cerebrovascular and is of great clinical significance.HR-VW-MRI includes 2D sequences and 3D sequences.3D sequences can reveal the vessel wall of intracranial and extracranial arteries in a single acquisition with a relatively short scan time compared with 2D sequences.3D sequences also can obtain the images of multiplanar reformation.During the application of 3D T1 sequences,enhancement of normal intracranial arteries was found on contrast-enhanced 3D T1 HR-VW-MRI.Knowledge of normal enhancement of intracranial arteries on gadolinium enhanced images is important in order to interpret of MRI scans for patients.We aim to investigate the phenomenon of enhancement of intracranial arterial wall on 3D T1 HR-VW-MRI.Methods:We retrospectively collected consecutive patients with 3D T1 HR-VW-MRI who were admitted to the First Hospital of Jilin University between 2014 and 2016.All patients had unenhanced and enhanced 3D T1 HR-VW-MRI images and detailed patient history information.Patients with primary angiitis of the central nervous system,reversible verebral vasoconstriction syndrome,or moyamoya disease were excluded.Arterial wall enhancement was classified as no enhancement(0 score),mild enhancement(1 score),and severe enhancement(2 scores).The intracranial internal carotid artery(ICA)was divided into the following segments:petrous ICA(C2),cavernous ICA(C3),and supraclinoid ICA(C4).Only main stem of middle cerebral artery(MCA),anterior cerebral artery(ACA),and posterior cerebral artery(PCA)were included.Intracranial vertebral artery(VA)and basilar artery(BA)were also analyzed.Results:A total of 21 patients were included in this study.The mean age of patients was 48 years(range,28-69 years old).There were 13 males and 8 females.At least one of the analyzed arteries was abnormal and excluded for 17 patients.A total of 282(89.5%,282/315)artery segments were analyzed from the 21 patients.The proportions of enhancement for each kind of artery segment were as follows:C3(100%,21/21),C2(100%,21/21),VA(76.19%,16/21),BA(22.22%,4/18),PCA(9.52%,2/21),MCA(5%,1/20),C4(4.76%,1/21),and ACA(4.76%,1/21).Kruskal-Wallis test showed that the degree of enhancement were significantly different among the 8 artery segnemts(P<0.001).Paired comparisons after Kruskal-Wallis test showed that the enhancement degree of ICA C3 was significantly higher than the other 7 segments(corrected P<0.05);the enhancement degree of ICA C2 was significantly higher than ICA C4,VA,BA,MCA,ACA,and PCA(corrected P<0.05);and the enhancement degree of VA was significantly higher than ICA C4,BA,MCA,ACA,and PCA(corrected P<0.05).For ICA C2,severe enhancement group had a significantly older age than mild enhancement group(P=0.002).Conclusions:Enhancement of vessel wall on contrast-enhanced 3D high? resolution vessel wall magnetic resonance imaging was commonly seen in ICA C3,ICA C2,and VA,but rarely seen in other intracranial arteries.The enhancement degree was positively associated with aging.The second part:Vessel wall differences between middle cerebral artery and basilar artery plaques on magnetic resonance imagingBackground and objective:Intracranial atherosclerotic disease is one of the important causes of ischemic stroke or transient ischemic attack,especially in Asian,Hispanic and African populations.Recently,with the rapid development of high? resolution vessel wall magnetic resonance imaging(HR-VW-MRI)techniques,there has been increasing interest in studies of intracranial atherosclerosis.The use of HR-VW-MRI has greatly improved the understanding of the pathophysiology of atherosclerosis.Atherosclerosis is a systemic disease that may involve several vascular beds,including coronary,peripheral,and renal arteries in addition to the cerebral arteries.However,a previous study showed that the carotid artery has a pattern of remodeling that was distinct from that of the femoral artery,which may be caused by differences in anatomy and blood flow.A recently study also showed that there was a significant difference in arterial remodeling between the arteries of the intracranial posterior circulation and intracranial anterior circulation in a Western population.We aimed to investigate if the features of plaques of the middle cerebral artery(MCA)were different from those of the basilar artery(BA)in the early and intermediate stages of atherosclerosis in a northern Chinese population.Methods:We retrospectively collected consecutive patients with acute ischemic stroke who were admitted to the First Hospital of Jilin University between 2015 and 2016.All patients had at least one MCA or BA plaque with early or mild(<50%stenosis)atherosclerosis identified using vessel HR-VW-MRI.Each plaque was classified as symptomatic,indeterminate,or asymptomatic according to criteria adapted from previous studies.Quantitative plaque measurement software was used to measure the parameters.The remodeling ratio,eccentricity index,and plaque range were compared between MCA and BA plaques using multilevel analysis.Results:A total of 71 patients with 101 plaques were included in this study.There were 70 plaques located in the MCA and 31 plaques located in the BA.Among the 70 MCA plaques,20 were classified as symptomatic,6 were indeterminate,and 44 were asymptomatic.Among the 31 BA plaques,11 were symptomatic,12 were indeterminate,and 8 were asymptomatic(Cochran-armitage trend test,P for trend = 0.022).The degree of stenosis was significantly associated with the remodeling ratio(adjusted P<0.001).The location of plaque(MCA or BA)(adjusted P=0.768)and classification of plaque were not significantly associated with the remodeling ratio.The location of plaque(MCA or BA)(adjusted P=0.387)and plaque burden(adjusted P=0.156)were not significantly associated with the eccentricity index.Symptomatic plaques were associated with a significantly higher eccentricity index(adjusted P=0.028)than asymptomatic plaques.The plaque burden was positively associated with plaque range(adjusted P=0.037).Symptomatic plaques were associated with a significantly smaller plaque range(adjusted P=0.042)than asymptomatic plaques.The location of plaque(MCA or BA)(adjusted P=0.553)was not significantly associated with the plaque range.Conclusions:In conclusion,by using multilevel model,this study found that the remodeling ratio,eccentricity index,and plaque range were not significantly different between non-advanced MCA and BA plaques after controlling for the degree of stenosis or plaque burden in a northern Chinese population.Symptomatic plaques were associated with a higher eccentricity index and smaller plaque range than asymptomatic plaques.A prospective study to investigate the progression of MCA and BA atherosclerosis may further answer the question of whether plaque features are different between MCA and BA plaques.The third part:Diagnosis of cerebral venous thrombosis with high? resolution vessel wall magnetic resonance imagingBackground and objective:Cerebral venous thrombosis(CVT)—i.e.,thrombosis of the dural sinuses and cerebral veins—is an uncommon form of stroke that affects approximately 5 people per million and accounts for about 0.5?1%of all strokes.The clinical manifestation of CVT is very diverse,which makes it more difficult to identify than other type of stroke.The current preferred method is the combination of magnetic resonance imaging(MRI)to visualise the thrombi in the dural sinuses and/or cerebral veins and magnetic resonance venography(MRV)to detect the filling defects of the corresponding vessels.However,these findings are not always evident,especially for small veins.Recently,several magnetic resonance black blood sequences have been used to evaluate cerebral vessels.Thrombus was high signal on T1 magnetic resonance black blood sequence.Therefore,the purpose of our study was to investigate the value of 3D fast spin-echo black blood sequence—i.e.,3D T1 SPACE(sampling perfection with application-optimized contrasts by using different flip angle evolutions)—for the diagnosis of CVT.We also investigated the value of 3D fast spin-echo black blood sequence in the follow up of CVT.Methods:We prospectively included patients who were suspected as having a CVT within one month of disease onset.Patients were admitted to the First Hospital of Jilin University between September 2014 and February 2016.The reference standard of CVT diagnosis was based on all of the conventional imaging tests(including susceptibility weighted imaging),clinical information,and prognosis information.The CVT was considered acute if the duration of symptoms was<3 days,subacute if it was 4-14 days,and chronic if it was>15 days.Results:Of the 31 patients and 403 venous segments evaluated in this study,the final diagnosis of the CVT was made for 14 patients(60 venous segments).The mean age of patients with CVT was 33 years(range,5-59 years old).There were 10 males and 4 females.The CVT was considered subacute for 10 patients and chronic for 4 patients at the time of MR examination.The median time between disease onset and the examination with MR was 12.5 days with a range of 8 to 27 days.The sensibility/specificity for T1 SPACE were 100%/100%per patient and 96.7%/100%per segment.The area under the curve based on patient for T1 SPACE was higher than that of standard magnetic resonance imaging(MRI)(1.0 vs.0.80,P=0.02)and standard MRI plus MRV(1.0 vs.0.91,P=0.14).The area under the curve based on segment for T1 SPACE was significant higher than that of standard MRI(0.98 vs.0.81,P<0.001)and standard MRI plus MRV(0.98 vs.0.87,P<0.001).Conclusions:3D T1 SPACE was helpful in the diagnosis of subacute and early chronic phase CVT.It can show the thrombus as evident high signal intensity.The hyperintense of thrombus may become isointense to hypointense at about one month.