Aetiology of extracranial carotid free-floating thrombus in a prospective multicentre cohort

Background Carotid free-floating thrombi(FFT)in patients with acute transient ischaemic attack(TIA)/stroke have a high risk of early recurrent stroke.Management depends on aetiology,which can include local plaque rupture,dissection,coagulopathy,malignancy and cardioembolism.Our objectives were to classify the underlying aetiology of FFT and to estimate the proportion of patients with underlying stenosis requiring revascularisation.Methods We prospectively enrolled consecutive patients presenting to three comprehensive stroke centres with acute TIA/stroke and ipsilateral internal carotid artery FFT.The aetiology of FFT was classified as:carotid atherosclerotic disease,carotid dissection,cardioembolism,both carotid atherosclerosis and cardioembolism,or embolic stroke of uncertain source(ESUS).Patients with carotid atherosclerosis were further subclassified as having≥50%or<50%stenosis.Results We enrolled 83 patients with confirmed FFT.Aetiological assessments revealed 66/83(79.5%)had carotid atherosclerotic plaque,4/83(4.8%)had a carotid dissection,10/83(12%)had both atrial fibrillation and carotid atherosclerotic plaque and 3/83(3.6%)were classified as ESUS.Of the 76 patients with atherosclerotic plaque(including those with atrial fibrillation),40(52.6%)had≥50%ipsilateral stenosis.Conclusions The majority of symptomatic carotid artery FFT are likely caused by local plaque rupture,more than half of which are associated with moderate to severe carotid stenosis requiring revascularisation.However,a significant number of FFTs are caused by non-atherosclerotic mechanisms warranting additional investigations.

Magnetic resonance imaging of disc space infection revisited： temporal changes

Background Magnetic resonance imaging （MRI） has advantages in showing pathologic changes of disc space infection,which is important in clinical treatment.The purpose of this study was to describe the MRI findings of disc space infections in relation to chronicity.Methods MRI of 60 patients from January 1,2002 to April 30,2012 in Ottawa Hospital were retrospectively evaluated by two radiologists blindly.All patients had histological confirmation,with 55 having microbiological confirmation as well.These patients were divided into acute （n=18）,subacute （n=21） and chronic （n=21） based on histological findings.The following potential signs of MRI finding were assessed：marrow edema,endplate erosions,disk fluid and height change,paraspinal mass,epidural collection,facet fluid and enhancement in the marrow,disc,paraspinal mass,and epidural involvement.Statistical analysis consisted of t-or F-tests and chi-square test.Results In the 60 patients,83 infected discs （single disc in 45 patients,2-4 discs in 15 patients） were found,including 22 discs in the acute group,30 discs in the subacute group,and 31 discs in the chronic group.There was a significant difference in the extent of marrow edema between the acute,subacute and chronic groups （P ＜0.05）,with a gradually increasing extent from acute to chronic.The extent of endplate erosions increased with chronicity,but was not statistically significant.There were significant differences in the disc fluid,epidural collection,and disc enhancement among the acute,subacute and chronic groups,as well as the facet fluid between acute and chronic groups （P ＜0.05）.There were no significant differences in the present probability of disc height loss,paraspinal mass,and marrow enhancement among the three groups （P ＞0.05）.Conclusions From acute to chronic infections,the extent of marrow edema and endplate erosions appeared to gradually increase.Epidural collections and facet fluid are most frequently found in the acute group,while disc fluid and disc enhancement are more common in the chronic patients.