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Background and Purpose: Rapid and reliable assessment of the perfusion-weighted imaging (PWI)/diffusion-weighted imaging (DWI) mismatch is required to promote its wider application in both acute stroke clinical routine and trials. We tested whether an evaluation based on the Alberta Stroke Program Early CT Score (ASPECTS) reliably identifies the PWI/DWI mismatch., Methods: A total of 232 consecutive patients with acute middle cerebral artery stroke who underwent pretreatment magnetic resonance imaging (PWI and DWI) were retrospectively evaluated. PWI-ASPECTS and DWI-ASPECTS were determined blind from manually segmented PWI and DWI volumes. Mismatch-ASPECTS was defined as the difference between PWI-ASPECTS and DWI-ASPECTS (a high score indicates a large mismatch). We determined the mismatch-ASPECTS cutoff that best identified the volumetric mismatch, defined as VolumeTmax>6s/VolumeDWI≥1.8, a volume difference≥15 mL, and a VolumeDWI<70 mL., Results: Inter-reader agreement was almost perfect for PWI-ASPECTS (κ=0.95 [95% confidence interval, 0.90-1]), and DWI-ASPECTS (κ=0.96 [95% confidence interval, 0.91-1]). There were strong negative correlations between volumetric and ASPECTS-based assessments of DWI lesions (ρ=-0.84, P<0.01) and PWI lesions (ρ=-0.90, P<0.01). Receiver operating characteristic curve analysis showed that a mismatch-ASPECTS ≥2 best identified a volumetric mismatch, with a sensitivity of 0.93 (95% confidence interval, 0.89-0.98) and a specificity of 0.82 (95% confidence interval, 0.74-0.89)., Conclusions: The mismatch-ASPECTS method can detect a true mismatch in patients with acute middle cerebral artery stroke. It could be used for rapid screening of patients with eligible mismatch, in centers not equipped with ultrafast postprocessing software., (© 2016 American Heart Association, Inc.)

Background and Purpose: Here, we assessed how sustained is reversal of the acute diffusion lesion (RAD) observed 24 hours after intravenous thrombolysis, and the relationships between RAD fate and early neurological improvement., Methods: We analyzed 155 consecutive patients thrombolyzed intravenously 152 minutes (median) after stroke onset and who underwent 3 MR sessions: 1 before and 2 after treatment (median times from onset, 25.6 and 54.3 hours, respectively). Using voxel-based analysis of diffusion-weighted imaging (DWI)1, DWI2, and DWI3 lesions on coregistered image data sets, we assessed the outcome of RAD voxels (hyperintense on DWI1 but not on DWI2) as transient or sustained on DWI3, and their relationships with early neurological improvement, defined as ΔNational Institutes of Health Stroke Scale ≥8 or National Institutes of Health Stroke Scale ≤1 at 24 hours. Tmax and apparent diffusion coefficient values were compared between sustained and transient RAD voxels., Results: The median (interquartile range) baseline National Institutes of Health Stroke Scale and DWI1 lesion volume were 11 (7-18) mL and 15.6 (6.0-50.9) mL, respectively. The median (interquartile range) RAD volume on DWI2 was 2.8 (1.1-6.6) mL, of which 70% was sustained on DWI3. Sixteen (10.3%) patients had sustained RAD ≥10 mL. As compared with transient RAD voxels, sustained RAD voxels had nonsignificantly higher baseline apparent diffusion coefficient values (median [interquartile range], 793 [717-887] versus 777 [705-869]×10(-6) mm(2)·s (-1), respectively; P=0.08) and significantly better perfusion (Tmax, mean±SD, 6.3±3.2 versus 7.8±4.0 s; P<0.001). At variance with transient RAD, the volume of sustained RAD was associated with early neurological improvement in multivariate analysis (odds ratio, 1.08; 95% confidence interval, [1.01-1.17], per 1-mL increase; P=0.03)., Conclusions: After thrombolysis, over two-thirds of the DWI lesion reversal captured on 24-hour follow-up MR is sustained. Sustained DWI lesion reversal volume is a strong imaging correlate of early neurological improvement., (© 2015 American Heart Association, Inc.)

Background and Purpose: Arterial wall enhancement on vessel wall MRI was described in intracranial inflammatory arterial disease. We hypothesized that circumferential aneurysmal wall enhancement (CAWE) could be an indirect marker of aneurysmal wall inflammation and, therefore, would be more frequent in unstable (ruptured, symptomatic, or undergoing morphological modification) than in stable (incidental and nonevolving) intracranial aneurysms., Methods: We prospectively performed vessel wall MRI in patients with stable or unstable intracranial aneurysms. Two readers independently had to determine whether a CAWE was present., Results: We included 87 patients harboring 108 aneurysms. Interreader and intrareader agreement for CAWE was excellent (κ=0.85; 95% confidence interval, 0.75-0.95 and κ=0.90; 95% confidence interval, 0.83-0.98, respectively). A CAWE was significantly more frequently seen in unstable than in stable aneurysms (27/31, 87% versus 22/77, 28.5%, respectively; P<0.0001). Multivariate logistic regression, including CAWE, size, location, multiplicity of aneurysms, and daily aspirin intake, revealed that CAWE was the only independent factor associated with unstable status (odds ratio, 9.20; 95% confidence interval, 2.92-29.0; P=0.0002)., Conclusions: CAWE was more frequently observed in unstable intracranial aneurysms and may be used as a surrogate of inflammatory activity in the aneurysmal wall., (© 2014 American Heart Association, Inc.)

Background and Purpose: Early neurological deterioration (END) after anterior circulation stroke is a serious clinical event strongly associated with poor outcome. Regarding specifically END occurring within 24 hours of intravenous recombinant tissue-type plasminogen activator, apart from definite causes such as symptomatic intracranial hemorrhage and malignant edema whose incidence, predictors, and clinical management are well established, little is known about END without clear mechanism (ENDunexplained)., Methods: We analyzed 309 consecutive patients thrombolysed intravenously ≤4.5 hours from onset of anterior circulation stroke. ENDunexplained was defined as a ≥4-point deterioration on 24-hour National Institutes of Health Stroke Scale, without definite mechanism on concomitant imaging. ENDunexplained and no-END patients were compared for pretreatment clinical and imaging (including magnetic resonance diffusion and diffusion/perfusion mismatch volumes) data and 24-hour post-treatment clinical (including blood pressure and glycemic changes) and imaging (24-hour recanalization) data, using univariate logistic regression. Exploratory multivariate analysis was also performed after variable reduction, with bootstrap analysis for internal validation., Results: Among 33 END patients, 23 (7% of whole sample) had ENDunexplained. ENDunexplained was associated with poor 3-month outcome (P<0.01). In univariate analysis, admission predictors of ENDunexplained included no prior use of antiplatelets (P=0.02), lower National Institutes of Health Stroke Scale score (P<0.01), higher glycemia (P=0.03), larger mismatch volume (P=0.03), and proximal occlusion (P=0.01), with consistent results from the multivariate analysis. Among factors recorded during the first 24 hours, only no recanalization was associated with ENDunexplained in multivariate analysis (P=0.02)., Conclusions: ENDunexplained affected 7% of patients and accounted for most cases of END. Several predictors and associated factors were identified, with important implications regarding underlying mechanisms and potential prevention of this ominous event., (© 2014 American Heart Association, Inc.)

Background and Purpose: The extent of diffusion lesion on pretreatment imaging is a risk factor for poor outcome and hemorrhagic transformation after thrombolysis, and volumes of 70 to 100 mL have been advocated as cut-offs. However, estimating diffusion-weighted imaging (DWI) lesion volume (VolDWI) in the acute setting may be cumbersome. We aimed to determine whether the DWI-Alberta Stroke Program Early CT Score (DWI-ASPECTS) can substitute for VolDWI., Methods: DWI-ASPECTS and VolDWI were measured retrospectively on pretreatment MRI (median onset-to-MRI delay=122 minutes) in 330 consecutively treated patients with middle cerebral artery stroke., Results: DWI-ASPECTS and VolDWI were strongly correlated (ρ=-0.82), but each DWI-ASPECTS point corresponded to a wide range of VolDWI. All patients with DWI-ASPECTS≥7 (n=207) had VolDWI<70 mL, whereas 32 of the 34 patients with DWI-ASPECTS<4 had VolDWI>100 mL. However, intermediate DWI-ASPECTS (4-6; n=89) corresponded to highly variable VolDWI (median, 66 mL; interquartile range, 40-98)., Conclusions: Although each DWI-ASPECTS point corresponds to a wide range of volumes, DWI-ASPECTS<4 or ≥7 may be used as reliable surrogates of VolDWI>100 or <70 mL, respectively.

Background and Purpose: To propose a T2*-MR adaptation of the computed tomography angiography-clot burden score (CBS), and assess its value as predictor of 24-hour recanalization and clinical outcome in anterior circulation stroke treated by intravenous thrombolysis ≤4.5 hours from onset., Methods: Two independent observers retrospectively analyzed pretreatment T2* images for evaluation of clot burden, using a 10-point scale T2*-CBS. Three points are subtracted for susceptibility vessel sign in the supraclinoid internal carotid artery, 2 points each for susceptibility vessel sign in the proximal and distal part of middle cerebral artery, and 1 point each for susceptibility vessel sign in middle cerebral artery branches (with a maximum of 2 points) and for susceptibility vessel sign in anterior cerebral artery. Associations with 24-hour recanalization and favorable outcome (3-month modified Rankin Scale score, ≤2) were assessed in multivariate analyses., Results: We analyzed 184 consecutive patients (mean age, 67 years) with median (interquartile range) admission National Institutes of Health Stroke Scale score and onset-to-treatment time of 15 (9-19) and 151 (120-185) minutes, respectively. The intraclass correlation for T2*-CBS between observers was 0.97 (95% confidence interval, 0.97-0.98). In multivariate analyses, T2*-CBS >6 was significantly associated with 24-hour recanalization (adjusted odds ratio, 5.1 [1.9-13.5]; P=0.001) or with favorable outcome (adjusted odds ratio, 4.2 [1.7-10.8]; P=0.003)., Conclusions: T2*-CBS, a new reproducible semiquantitative score adapted from the computed tomography angiography-CBS, is associated with 24-hour recanalization and 3-month outcome after intravenous thrombolysis. This score needs external validation and could be useful to identify poor responders to intravenous thrombolysis.

Background and Purpose: In acute stroke, diffusion-weighted imaging (DWI) lesions are commonly considered markers of irreversible ischemia yet can occasionally reverse. However, the extent and clinical correlates of DWI reversal in thrombolyzed patients remain unclear. We assessed the extent of reversible acute DWI lesions (RADs) and their relationships with clinical outcome in patients thrombolyzed≤4.5 hours from onset., Methods: Data were retrospectively analyzed. RAD was defined as an acute DWI lesion not part of a 24-hour DWI lesion as determined voxelwise. Associations with an early neurological improvement (early neurological improvement=ΔNational Institutes of Health Stroke Scale≥8 or National Institutes of Health Stroke Scale≤2 at 24 hours) or an excellent outcome (modified Rankin Scale≤1) were assessed in multivariate analyses., Results: One hundred seventy-six patients were included. The median (interquartile range) time to treatment from onset was 150 minutes (120-194). Eighty-nine patients (50%) exhibited visually-detectable RAD irrespective of its extent. Over the whole population, the median percentage and volume of RAD were 11% (4-36) and 2.4 mL (0.5-8). Subtracting RAD from initial DWI altered perfusion-weighted imaging-DWI classification in 5 of 100 patients (shift from "no mismatch" to "mismatch" profile in all). Percent RAD was significantly greater in patients treated≤3 hours (P=0.049), without proximal occlusion (P=0.003), and in 24-hour recanalizers (P<0.001). Early neurological improvement was independently associated with percent RAD. This association increased with percent RAD split in quartiles in a "dose-dependent" manner (P for trend=0.01). Excellent outcome was independently associated with percent RAD (P for trend<0.001)., Conclusions: DWI reversal was often sizeable in patients treated≤4.5 hours. It was strongly associated with, albeit not necessarily causal for, early neurological improvement.

Background and Purpose: It is unclear whether strokes in patients with spontaneous cervical artery dissection (CAD) are due to secondary thromboembolism or to a reduction in cerebral blood flow from the primary cervical lesion. The aim of this study was to identify the most likely mechanism of stroke using cervical and cerebral imaging parameters in patients with CAD., Methods: The study was approved by the local Ethics Committee. Informed consent was waived. We retrospectively evaluated the cerebrovascular ultrasound, cervical MR angiography, and stroke brain MRI in consecutive patients with CAD. An embolic mechanism was considered in the case of direct visualization of an intracranial embolism as a susceptibility vessel sign on T2* or in the case of pial artery territory infarction on diffusion-weighted imaging. A hemodynamic mechanism was considered in the case of watershed infarction and in the case of an association of watershed infarction and pial artery territory infarction when ≥ 2 of the following were present: severe stenotic or occlusive CAD, reduced intracranial velocity on cerebrovascular ultrasound or signal on MR angiography, or hyperintense vessel sign on fluid-attenuated inversion recovery. The remaining patients were considered to have a mixed mechanism., Results: Of 172 consecutive patients with CAD, 100 (58%) had acute stroke on diffusion-weighted imaging. Stroke was attributed to a thromboembolic mechanism in 85 of 100 patients, a hemodynamic mechanism in 12 of 100 patients, and a mixed mechanism in 3 of 100 patients., Conclusions: Stroke in patients with CAD is most frequently associated with both direct and indirect signs of artery-to-artery embolization on imaging, a finding that should help design future therapeutic trials.

Background and Purpose: In stroke attributable to spontaneous dissection of the cervical artery, it is unclear whether the occurrence and pattern of stroke depend on the degree of stenosis., Methods: In 147 consecutive dissection of the cervical artery patients with (n=88) and without stroke (n=59), we compared the number, volume, and patterns of cerebral diffusion-weighted imaging stroke lesions among patients with <70% stenosis (Group 1), ≥70% stenosis (Group 2), and occlusion (Group 3)., Results: The presence (26 of 45 in Group 1, 32 of 59 in Group 2, 30 of 43 in Group 3; P=0.27) and the number of diffusion-weighted imaging lesions (mean±SD [interquartile range], 3.5±3.9 [1-4] in Group 1; 4.2±4.1 [1-5] in Group 2; 3.3±4.0 [1-3] in Group 3; P=0.85) were independent of lumen patency, whereas volume of diffusion-weighted imaging lesions was larger in occlusive dissection of the cervical artery (82±90 mm [17-91] versus 34±54 [2-48]; P=0.03). There were no differences in the breakdown of diffusion-weighted imaging lesion patterns according to degree of stenosis., Conclusions: The occurrence and diffusion-weighted imaging lesion patterns in dissection of the cervical artery patients may not be influenced by the degree of stenosis of the dissected artery. Occlusive dissection of the cervical artery was associated with larger infarcts.

Background and Purpose: The purposes of this study were to assess the relationships between anatomic and technical factors and the 30-day risk of stroke or death after carotid angioplasty and stenting in the Endarterectomy versus Stenting in Patients with Symptomatic Severe Carotid Stenosis (EVA-3S) trial and to perform a systematic review of the literature., Methods: We included patients from EVA-3S in whom carotid stenting was attempted irrespective of allocated treatment. Two radiologists blinded to clinical data independently assessed the aortic arch and carotid arteries on procedural angiograms. In addition, we performed a systematic review of studies that reported 30-day risk of stroke or death in relation with arterial anatomy and technique. Outcomes were stroke or death and stroke occurring within 30 days of the carotid angioplasty and stenting procedure., Results: Two hundred sixty-two patients from EVA-3S fulfilled the inclusion criteria (including 1 initially allocated to surgery and 13 in whom stent insertion failed).Within 30 days after the procedure, 25 (9.5%) patients had a stroke or had died. The risk of stroke or death was higher in patients with internal carotid artery-common carotid artery angulation ≥60° (relative risk, 4.96; 2.29 to 10.74) and lower in those treated with cerebral protection devices (relative risk [RR], 0.38; 0.17 to 0.85). In the systematic review (56 studies; 34 398 patients), the risk of stroke or death was higher in patients with left-sided carotid angioplasty and stenting (RR, 1.29; 1.05 to 1.58), increased internal carotid artery-common carotid artery angulation (RR, 3.41; 1.52 to 7.63), and when the target internal carotid artery stenosis was >10 mm (RR, 2.36; 1.28 to 3.38). There was no significant increase in risk of stroke or death in patients with Type III aortic arch, aortic arch calcification, or with ostial involvement, calcification, ulceration or degree of stenosis of the target internal carotid artery stenosis. The use of a cerebral protection device was associated with a lower risk of stroke or death (RR, 0.55; 0.41 to 0.73). Risk was not related with stent or cerebral protection device type., Conclusions: Our results strongly suggest that some technical and anatomic factors, especially extreme angulation of the carotid artery, have an impact on the risks of carotid angioplasty and stenting.

Background and Purpose: The ABCD(2) score has been shown to predict the early risk of stroke after transient ischemic attack (TIA). The additional predictive value of diffusion-weighted imaging (DWI) and TIA etiology is not well known., Methods: From January 2003 to June 2007, 343 consecutive patients (mean+/-SD age, 62.4+/-15.4 years) with TIA were admitted to our stroke unit. Most (339) patients underwent DWI and all had an etiologic work-up and were followed up for 3 months. The predictive value of the ABCD(2) score, positive DWI findings, large-artery atherosclerosis (LAA), and atrial fibrillation (AF) with respect to occurrence of ischemic stroke at 1 week and 3 months was assessed., Results: DWI was positive in 136 (40%) patients. Sixty (17%) patients had LAA and 27 (8%) had AF. Patients with positive DWI findings were more likely to have unilateral weakness (odds ratio [OR]=2.2; 95% CI, 1.3 to 3.7), TIA duration >/=60 minutes (OR=2.6; 95% CI, 1.3 to 5.2), ABCD(2) >5 (OR=4.7; 95% CI, 2.0 to 11.0), LAA (OR=1.8; 95% CI, 1.0 to 3.1), and AF (OR=3.5; 95% CI, 1.5 to 8.0). During follow-up, 5 patients had a stroke within 7 days (absolute risk=1.5%, 95% CI, 0.3% to 2.7%), and 10 had a stroke within 3 months (absolute risk=2.9%; 95% CI, 1.1% to 4.7%). All early strokes but 1 occurred in patients with positive DWI findings. ABCD(2) score and positive DWI findings were associated with an increased 7-day and 3-month risk of stroke. At 3 months, ABCD(2) score >5 (hazard ratio=10.1; 95% CI, 1.1 to 93.4), positive DWI result (hazard ratio=8.7; 95% CI, 1.1 to 71.0), and LAA (hazard ratio=3.4; 95% CI, 1.0 to 11.8) were independently associated with an increased risk of stroke. There was no association with AF., Conclusions: Taking DWI and TIA etiology into account in addition to the ABCD(2) score improves the prediction of the early risk of stroke after TIA.

Background and Purpose: Although MRI is increasingly proposed to investigate composition of carotid atherosclerosis, its reproducibility has rarely been addressed. We assessed the reproducibility of MRI for the identification and quantification of carotid atherosclerotic plaque components., Methods: Using published criteria, 2 readers independently analyzed the carotid MRI (1.5-T MR units with a 4-channel phased-array surface coil, Machnet) of 85 consecutive patients with symptomatic (40% to 69% according to NASCET method) or asymptomatic (60% or greater) carotid artery stenosis enrolled in an ongoing prognostic study. One reader reevaluated all images. Fibrous cap was also secondarily identified independently on T2-weighted and time-of-flight (TOF) images., Results: Intraobserver agreement was substantial for the identification of calcifications (kappa [kappa]=0.70; 95% CI: 0.54 to 0.86) and lipid-rich/necrotic core (LR/NC) (kappa=0.69; 0.31 to 0.86), almost perfect for hemorrhages (kappa=0.82; 0.68 to 0.96), and moderate (kappa=0.58; 0.27 to 0.88) and fair (kappa=0.33; 0.09 to 0.56) for fibrous cap identification on T2-weighted and TOF images, respectively. Interobserver agreement was substantial for the identification of calcifications (kappa=0.74; 0.59 to 0.89) and hemorrhages (kappa=0.62; 0.43 to 0.81), and moderate for LR/NC (kappa=0.58; 0.20 to 0.95). Agreement was fair for fibrous cap identification on both T2-weighted (kappa=0.28; -0.03 to 0.59) and on TOF images (kappa=0.26; 0.04 to 0.48). Agreement between T2 and TOF images for fibrous cap identification was slight (kappa=0.16; 0.01 to 0.31). Intra- and interobserver reproducibility for quantitative area measurements of vessel, lumen, plaque, LR/NC, and fibrous components was high with intraclass correlation coefficients ranging from 0.73 to 0.99. However, for the LR/NC, the interval delimited by the Bland-Altman graphs was wide in comparison to the mean., Conclusions: Vessel and plaque quantification is reproducible. Reproducibility of MRI for identifying and quantifying carotid plaque components is overall acceptable, but there is still significant variability that should be taken into account in the design of prognosis studies and clinical trials. Reproducibility for fibrous cap identification needs to be improved.

Background and Purpose: Hyperintense vessel sign (HVS) on fluid-attenuated inversion recovery (FLAIR) has been described in hyperacute stroke patients with arterial occlusion. We sought to determine whether HVS was more frequent in patients with intracerebral arterial stenoses than in those without stenosis regardless of the presence of a brain infarct., Methods: In this case-control study (19 symptomatic patients with multiple intracerebral arterial stenoses compared with 19 age-matched asymptomatic patients without stenosis), we looked for HVS (ie, focal or tubular hyperintensities in the subarachnoid space) on FLAIR images. We compared the proportion of HVS-positive patients in the 2 groups and evaluated the concordance between the arterial distribution of stenoses on angiogram and that of HVS on FLAIR., Results: HVS was found in 13 of 19 patients (68%) in the study group and 1 of 19 control patients (5.2%) (P<0.0001). The concordance between the territorial distribution of stenoses on angiogram and HVS on FLAIR was higher for the right and left middle cerebral artery (kappa=0.6 and 0.63, respectively) compared with the right and left anterior cerebral artery (kappa=0.35 and 0.2, respectively). HVSs were observed in 1 of 7 patients with posterior cerebral artery stenoses on angiogram. HVSs were seen equally in patients with acute focal (7 of 10) or diffuse (6 of 9) cerebral involvement. In the 6 HVS-positive patients with acute stroke confirmed by MRI, additional HVSs were observed in a different arterial territory than that of the stroke lesion., Conclusions: Although their significance remains unclear, multiple HVSs are more frequently observed in symptomatic patients with multiple intracerebral stenoses than in asymptomatic patients without stenosis.

Background and Purpose: Patent foramen ovale (PFO) has been identified as a potential risk factor for stroke, but the mechanisms of PFO-associated stroke remain unsettled. The aim of our study was to evaluate possible differences in stroke risk factors and stroke patterns between patients with and without PFO that may give clues to the mechanism of PFO-associated stroke., Methods: This prospective, multicentric study involved 581 young cryptogenic stroke patients. The presence of PFO and atrial septal aneurysm was assessed by transesophageal echocardiography and reviewed independently by 2 experienced sonographers. Clinical, brain, and vascular imaging findings were reviewed by 2 neurologists and 2 neuroradiologists., Results: Of the 581 stroke patients, 267 (45.9%) had PFO. Patients with PFO were younger (OR, 0.95; 95% CI, 0.93 to 0.97) and less likely to have traditional risk factors such as hypertension (OR, 0.49; 95% CI, 0.28 to 0.85), hypercholesterolemia (OR, 0.56; 95% CI, 0.34 to 0.93), or current smoking (OR, 0.67; 95% CI, 0.47 to 0.97). Features suggestive of paradoxical embolism, such as Valsalva-provoking activities or deep vein thrombosis, were not more frequent in patients with PFO. Migraine was more common in patients with PFO (27.3%) than in those without PFO (14.0%). PFO (OR, 1.75; 95% CI, 1.08 to 2.82), particularly when associated with atrial septal aneurysm (OR, 2.71; 95% CI, 1.36 to 5.41), was significantly associated with migraine after adjustment for age and sex., Conclusions: Differences in stroke risk factors and stroke patterns suggest that different stroke mechanisms occur in patients with and without PFO. PFO is significantly and independently associated with migraine, and this association is even stronger in patients with PFO and atrial septal aneurysm.

Background and Purpose: The natural history of aneurysmal forms of cervical artery dissection (CAD) is ill defined. The aims of this study were to assess (1) clinical and anatomic outcome of aneurysmal forms of extracranial internal carotid artery (ICA) and vertebral artery (VA) dissections and (2) factors associated with aneurysmal forms of CAD., Methods: Seventy-one consecutive patients with CAD were reviewed. Aneurysmal forms of CAD were identified from all available angiograms by 2 neuroradiologists. The frequency of arterial risk factors, of multiple vessel dissections, and of artery redundancies was compared in patients with and without aneurysm. Patients with aneurysm were invited by mail to undergo a final clinical and radiological evaluation., Results: Of the 71 patients, 35 (49.3%) had a total of 42 aneurysms. Thirty aneurysms were located on a symptomatic artery (ICA, 23; VA, 7) and 12 on an asymptomatic artery (ICA, 10; VA, 2). Patients with aneurysm had multiple dissections of cervical vessels (18/35 versus 7/36; P:=0.005) and arterial redundancies (20/35 versus 11/36; P:=0.02) more frequently than patients without aneurysm. They were also more often migrainous (odds ratio=2.7 [95% CI, 0.8 to 8.5]) and tobacco users (odds ratio=2.2 [95% CI, 0.7 to 6.3]). Clinical and anatomic follow-up information was available for 35 (100%) and 33 patients (94%), respectively. During a mean follow-up of >3 years, no patient had signs of cerebral ischemia, local compression, or rupture. At follow-up, 46% of the aneurysms involving symptomatic ICA were unchanged, 36% had disappeared, and 18% had decreased in size. Resolution was more common for VA than for ICA aneurysms (83% versus 36%). None of the aneurysms located on an asymptomatic ICA had disappeared., Conclusions: Although aneurysms due to CAD frequently persist, patients carry a very low risk of clinical complications. This favorable clinical outcome should be kept in mind before potential harmful treatment is contemplated.

Background and Purpose: The typical magnetic resonance imaging picture of arterial dissection, namely, a narrowed eccentric signal void surrounded by a semilunar signal hyper-intensity (corresponding to the mural hematoma) on T1- and T2-weighted images, has been repeatedly reported, but the sensitivity of magnetic resonance imaging for the diagnosis of cervical dissection is poorly known. Another technique, dynamic computed tomography, may provide evidence of mural hematoma, but there has been no systematic evaluation of this technique. The aims of this study were to assess both the sensitivity of routine 0.5-T magnetic resonance imaging for the detection of a typical picture of cervical artery dissection and the value of dynamic computed tomographic scans to provide evidence of dissecting hematoma., Methods: Fifteen consecutive patients with angiographically confirmed extracranial internal carotid (n = 9) or vertebral (n = 10) dissections were studied using a standardized 0.5-T spin-echo magnetic resonance imaging protocol with axial slices. Twelve of these patients had dynamic computed tomographic scans at the site of the dissection suggested by angiography., Results: A typical magnetic resonance imaging picture of cervical artery dissection was observed in 12 of 15 (80%) patients and in 13 of 19 (68%) dissected vessels. The sensitivity of magnetic resonance imaging was higher in internal carotid (78%) than in vertebral (60%) dissections and in stenotic-type dissections (85%) than in occlusive or aneurysmal-type dissections. The dynamic computed tomographic scan showed the mural hematoma in 11 of the 12 (92%) patients and in 12 of 15 (80%) dissected vessels., Conclusions: Routine 0.5-T magnetic resonance imaging with axial slices is a sensitive technique for the diagnosis of dissection, but in about 20% of patients with cervical artery dissection magnetic resonance imaging will demonstrate no typical abnormality. Dynamic computed tomographic scans are a sensitive neuroimaging procedure to confirm the presence of the mural hematoma, but it needs to be directed by prior angiography.

Lateral sinus thrombosis may be difficult to differentiate angiographically from lateral sinus hypoplasia, which mainly affects its proximal transverse portion. Using magnetic resonance imaging, we evaluated six patients who demonstrated poor filling or lack of filling of one or both lateral sinuses at angiography. In each patient, magnetic resonance imaging unambiguously demonstrated either lateral sinus thrombosis or lateral sinus hypoplasia. The latter was characterized by a frank asymmetry in size (surface of section) of the transverse portion of the lateral sinuses on parasagittal images without any abnormal signal in the course of the sinus. Lateral sinus thrombosis was indicated by increased intraluminal signal on all planes and with all pulse sequences. By virtue of its freedom from bone-related artifact, its multiplanar imaging capability, and its sensitivity to both blood flow and thrombus formation, magnetic resonance imaging is an excellent tool for the evaluation of lateral sinus thrombosis or hypoplasia.