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Introduction: The aim of this study was to assess the agreement between postmortem computed tomography (PMCT) and autopsy in detecting traumatic head injuries., Materials and Methods: Consecutive cases of death that underwent both unenhanced PMCT and conventional autopsy were collected from our institution database during a period of 3 years and reviewed retrospectively. PMCT images were reviewed for the presence of fractures (cranial vault, skull base, facial bones and atlas/axis) and intracranial hemorrhage. Kappa values were calculated to determine the agreement between PMCT and autopsy reports., Results: 73 cases were included, of which 44 (60%) had head trauma. Agreement between PMCT and autopsy was almost perfect (κ = 0.95) for fractures and substantial (κ = 0.75) for intracranial hemorrhage. PMCT was superior to autopsy in detecting facial bone and upper cervical spine fractures, and intraventricular hemorrhage. However, in some cases thin extra-axial blood collections were missed on PMCT., Conclusions: The agreement between PMCT and autopsy in detecting traumatic head injuries was good. Using a combination of both techniques increases the quality of postmortem evaluation because more lesions are detected., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Background and Purpose: Whether to withhold recanalization treatment when the diffusion-weighted imaging (DWI) lesion exceeds a given volume is unsettled. Our aim was to assess the impact of recanalization on outcome in patients with baseline DWI lesion ≥70 mL (DWI≥70 mL) treated ≤4.5 hours from onset. We hypothesized that recanalization is beneficial in a sizeable fraction of these patients and that this is associated with a larger DWI lesion reversal., Methods: We analyzed 267 consecutive patients treated with intravenous recombinant tissue-type plasminogen activator for middle cerebral artery territory stroke in whom an occlusion was present on magnetic resonance angiography and 24-hour recanalization and 90-day clinical outcome could be assessed. After stratification relative to the 70-mL DWI lesion cut point, we calculated the odds ratio for recanalization of the primary arterial occlusive lesion (AOL score ≥2) to predict favorable outcome (modified Rankin scale score ≤2). DWI lesion reversal was compared between recanalizers with DWI≥70 mL with favorable and unfavorable outcomes., Results: Median (interquartile range) DWI lesion volume was 22 mL (10-60), and median onset time to imaging was 116 minutes (86-151). Twelve (22%) of the 54 patients with DWI≥70 mL experienced favorable outcome, of which 9 had recanalized. In patients with DWI≥70 mL, recanalization was significantly associated with favorable outcome after adjustment for age and National Institutes of Health Stroke Scale (odds ratio =4.72 [1.09-20.32]; P=0.0375). Among recanalizers with DWI≥70 mL, absolute and relative DWI reversal volumes were larger in those with favorable as compared with unfavorable outcome (18.8 mL [12.2-47.6] versus 8.5 mL [4.3-31.1]; P=0.17; and 19.6% [10.9-62.8] versus 8.7% [3.9-16.5], respectively; P=0.049)., Conclusions: Patients with DWI lesion volume ≥70 mL can benefit from recanalization after intravenous recombinant tissue-type plasminogen activator. This may partly reflect a larger amount of DWI lesion reversal., (© 2016 American Heart Association, Inc.)

Background and Purpose: Fluid-attenuated inversion recovery vascular hyperintensities (FVH) beyond the boundaries of diffusion-weighted imaging (DWI) lesion (FVH-DWI mismatch) have been proposed as an alternative to perfusion-weighted imaging (PWI)-DWI mismatch. We aimed to establish whether FVH-DWI mismatch can identify patients most likely to benefit from recanalization., Methods: FVH-DWI mismatch was assessed in 164 patients with proximal middle cerebral artery occlusion before intravenous thrombolysis. PWI-DWI mismatch (PWITmax>6sec/DWI>1.8) was assessed in the 104 patients with available PWI data. We tested the associations between 24-hours complete recanalization on magnetic resonance angiography and 3-month favorable outcome (modified Rankin Scale score ≤2), stratified on FVH-DWI (or PWI-DWI) status., Results: FVH-DWI mismatch was present in 121/164 (74%) patients and recanalization in 50/164 (30%) patients. The odds ratio for favorable outcome with recanalization was 16.2 (95% confidence interval, 5.7-46.5; P<0.0001) in patients with FVH-DWI mismatch and 2.6 (95% confidence interval, 0.6-12.1; P=0.22) in those without FVH-DWI mismatch (P=0.048 for interaction). Recanalization was associated with favorable outcome in patients with PWI-DWI mismatch (odds ratios, 9.9; 95% confidence interval, 3.1-31.3; P=0.0001) and in patients without PWI-DWI mismatch (odds ratios, 7.0; 95% confidence interval, 1.1-44.1; P=0.047), P=0.76 for interaction., Conclusion: The FVH-DWI mismatch may rapidly identify patients with proximal occlusion most likely to benefit from recanalization., (© 2016 American Heart Association, Inc.)

Background and Purpose: In acute stroke with proximal artery occlusion, FLAIR vascular hyperintensities observed beyond the boundaries of the cortical lesion on DWI (newly defined "FLAIR vascular hyperintensity-DWI mismatch") may be a marker of tissue at risk of infarction. Our aim was to compare the occurrence of FLAIR vascular hyperintensity-DWI mismatch relative to that of perfusion-weighted imaging-DWI mismatch in patients with proximal MCA occlusion before IV thrombolysis., Materials and Methods: In 141 consecutive patients with proximal MCA occlusion, 2 independent observers analyzed FLAIR images for the presence of FLAIR vascular hyperintensity-DWI mismatch before IV thrombolysis. PWI-DWI mismatch was defined as Volumehypoperfusion > 1.8 × VolumeDWI, with Volumehypoperfusion > 6 seconds on time to maximum value of the residue function maps in the 94 patients with available PWI. The presence of FLAIR vascular hyperintensity-DWI mismatch, PWI-DWI mismatch, and infarct growth on 24-hour follow-up DWI was compared., Results: A FLAIR vascular hyperintensity-DWI mismatch was present in 102/141 (72%) patients, with an excellent interobserver reliability (κ = 0.91), and a PWI-DWI mismatch, in 61 of the 94 (65%) patients with available PWI. FLAIR vascular hyperintensity-DWI mismatch predicted PWI-DWI mismatch with a sensitivity of 92% (95% CI, 85%-99%) and a specificity of 64% (95% CI, 47%-80%). Patients with FLAIR vascular hyperintensity-DWI mismatch had smaller initial DWI lesion and larger infarct growth (P < .001) than patients without FLAIR vascular hyperintensity-DWI mismatch, even though their final infarcts remained smaller (P < .001)., Conclusions: Albeit being moderately specific, probably due to inclusion of oligemic tissue, the FLAIR vascular hyperintensity-DWI mismatch identifies large PWI-DWI mismatch with high sensitivity., (© 2015 by American Journal of Neuroradiology.)

Because of its excellent sensitivity and specificity to diagnose arterial ischemic stroke (AIS) in the acute phase, MRI answers the main questions to guide treatment in "candidates" for thrombolysis. It lasts less than ten minutes, can confirm the diagnosis of AIS and distinguish it from hematomas and other "stroke mimics". It can identify the ischemic penumbra (perfusion-diffusion mismatch), determine the site of occlusion and provide prognostic information to adapt treatment in some cases in which the indications are poorly defined. In light of the most recent scientific findings, MRI can guide the treatment turning it into the investigation of choice in "candidates" for thrombolysis., (Copyright © 2014 Éditions françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Background and Purpose: Unstable clinical course characterizes the first 24 hours after thrombolysis for anterior circulation stroke, including early neurological deterioration (END), a secondary complication consistently predictive of poor outcome. Apart from straightforward causes, such as intracerebral hemorrhage and malignant edema, the mechanism of END remains unclear in the majority of cases (ENDunexplained). Based on the core/penumbra model, we tested the hypothesis that ENDunexplained is caused by infarct growth beyond the initial penumbra and assessed the associated vascular patterns., Methods: From our database of consecutive thrombolyzed patients (n=309), we identified 10 ENDunexplained cases who had undergone both admission and 24-hour MRI. Diffusion-weighted imaging lesion growth both within and beyond the acute penumbra (Tmax>6 seconds) was mapped voxelwise. These 10 cases were compared with 30 no-END controls extracted from the database blinded to 24-hour diffusion-weighted imaging to individually match cases (3/case) according to 4 previously identified clinical and imaging variables., Results: As predicted, lesion growth beyond initial penumbra was present in 9 of 10 ENDunexplained patients (substantial in 8) and its volume was significantly larger in cases than controls (2P=0.047). All ENDunexplained cases had proximal arterial occlusion initially, of which only 2 had recanalized at 24 hours., Conclusions: In this exploratory study, most instances of ENDunexplained were related to diffusion-weighted imaging growth beyond acute penumbra. Consistent presence of proximal occlusion at admission and lack of recanalization at 24 hours in most cases suggest that hemodynamic factors played a key role, via for instance systemic instability/collateral failure or secondary thromboembolic processes. Preventing END after tissue-type plasminogen activator using, eg, early antithrombotics may therefore be feasible., (© 2014 American Heart Association, Inc.)

Background and Purpose: In acute ischemic stroke, white matter (WM) is considered more resistant to infarction than gray matter (GM). To test this hypothesis, we compared the fate of WM and GM voxels belonging to the acute diffusion-weighted imaging (DWI) lesion, expecting WM voxels to be more prone to reversal after thrombolysis., Methods: Reversible acute DWI (RAD) lesion was defined voxel-wise as an acute lesion on initial DWI (DWI1) with no visible lesion on 24-hour DWI (DWI2). Only patients with RAD lesions >10 mL and >10% of DWI1 from our previously reported cohort were eligible. The core was defined as voxels hyperintense on DWI1 and DWI2. Semiautomated segmentation of DWI1, core, and RAD lesions, normalization into standard space, and WM/GM segmentation allowed calculations of WM/GM proportions in each region of interest using a voxel-counting algorithm., Results: Thirty patients were eligible (RAD lesion median volume [interquartile range], 23.3 mL [19.1-35.0 mL]; onset-to-treatment time, 134 minutes [105-185 minutes]). WM voxels fraction was greater in RAD lesions than in the core (59.4% [52.8%-68.9%] versus 49.6% [43.0%-57.5%]; P=0.011). The proportion of reversibility was greater for WM than for GM voxels (60.8% [25.5%-88.7%] versus 53.5% [21.1%-77.3%]; P=0.02). The percentage of RAD lesions increased with the proportion of WM present in the acute DWI lesion (P<0.0001; R=0.67)., Conclusions: Acute DWI lesions predominantly involving WM may be more prone to reversal and, hence, to respond to therapy than their GM counterparts.

Background and Purpose: Our aim was to estimate the prevalence of negative diffusion-weighted imaging (DWI) with total perfusion-diffusion mismatch in a large series of anterior circulation stroke patients treated with thrombolysis and to describe the characteristics of these patients., Materials and Methods: From January 2006 to December 2010, a retrospective search was made for total perfusion-diffusion (PWI-DWI) mismatch patterns on pretreatment 1.5-T MRI scans of 166 consecutive thrombolyzed patients taken<4.5 h after onset of anterior stroke. A total mismatch profile corresponded to an absence of initial DWI signal changes with hypoperfusion (T(max)>6 s) on PWI. Clinical and MRI characteristics were compared between DWI+ and DWI- patients., Results: Five (3%) patients had a normal initial DWI. All had stable substantial clinical deficits (NIHSS scores ≥ 6) and large perfusion abnormalities - in other words, 'total mismatch' - and infarcts in the acutely hypoperfused area on follow-up imaging. While DWI- and DWI+ patients did not significantly differ in any of the pretreatment imaging or clinical variables except for the extent of PWI-DWI mismatch, DWI- patients had lower NIHSS scores at 24 h, and were more likely to show early neurological improvement (Δ0-24 h NIHSS ≥ 8) and good outcomes (mRS ≤ 2) at the time of hospital discharge., Conclusion: Total mismatch i.e. failure of DWI to reveal any ischemic tissue despite a large perfusion defect, can be observed before thrombolysis even in stroke patients with stable substantial neurological deficits. However, this rare MRI profile is associated with a favorable outcome after thrombolysis., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Background and Purpose: The DRAGON score, which includes clinical and computed tomographic scan parameters, showed a high specificity to predict 3-month outcome in patients with acute ischemic stroke treated by intravenous tissue plasminogen activator. We adapted the score for patients undergoing MRI as the first-line diagnostic tool., Methods: We reviewed patients with consecutive anterior circulation ischemic stroke treated ≤ 4.5 hour by intravenous tissue plasminogen activator between 2003 and 2012 in our center, where MRI is systematically implemented as first-line diagnostic work-up. We derived the MRI-DRAGON score keeping all clinical parameters of computed tomography-DRAGON (age, initial National Institutes of Health Stroke Scale and glucose level, prestroke handicap, onset to treatment time), and considering the following radiological variables: proximal middle cerebral artery occlusion on MR angiography instead of hyperdense middle cerebral artery sign, and diffusion-weighted imaging Alberta Stroke Program Early Computed Tomography Score (DWI ASPECTS) ≤ 5 instead of early infarct signs on computed tomography. Poor 3-month outcome was defined as modified Rankin scale >2. We calculated c-statistics as a measure of predictive ability and performed an internal cross-validation., Results: Two hundred twenty-eight patients were included. Poor outcome was observed in 98 (43%) patients and was significantly associated with all parameters of the MRI-DRAGON score in multivariate analysis, except for onset to treatment time (nonsignificant trend). The c-statistic was 0.83 (95% confidence interval, 0.78-0.88) for poor outcome prediction. All patients with a MRI-DRAGON score ≤ 2 (n=22) had a good outcome, whereas all patients with a score ≥ 8 (n=11) had a poor outcome., Conclusions: The MRI-DRAGON score is a simple tool to predict 3-month outcome in acute stroke patients screened by MRI then treated by intravenous tissue plasminogen activator and may help for therapeutic decision.

Objective: Up to 40% of patients with transient ischemic attack (TIA) demonstrate lesions on diffusion-weighted magnetic resonance imaging (DWI). However, the time course of these ischemic lesions is not well known. Some lesions could vanish soon after symptom onset whereas others could be visible only after a certain delay. Based on a population of TIA patients imaged twice with DWI within the first week after onset, our aim was to estimate the rate of patients with DWI reversible ischemic lesion or with delayed DWI positivity., Methods: We retrospectively compared DWI at admission (DWI(1), median = 15 hours after TIA) with follow-up DWI (DWI(2), median = 47 hours) in 64 consecutive TIA over a 7-month period. DWI was reviewed in consensus by two readers, blinded to clinical information. Number, extent and arterial distribution of lesions were assessed., Results: DWI(1) and DWI(2) showed similar findings in 55 TIA patients (32 with and 23 without ischemic lesions). In nine (14%) patients, changes were observed on DWI(2): presence of ischemic lesions despite normal DWI(1) (n = 3), increase in lesion size (n = 3), or partial or complete lesion reversibility (n = 3)., Conclusion: In most TIA cases, ischemic lesions captured by early DWI and 48-hour DWI are similar. However, some ischemic lesions vanish rapidly while lesion visibility is delayed in other cases., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Objective: Intraplaque hemorrhage (IPH) is an emerging marker of plaque instability. However, little is known about the relationships between IPH and traditional risk factors and whether these relationships differ between symptomatic and asymptomatic disease., Methods and Results: Two hundred thirty-four patients with symptomatic (n=114) or asymptomatic (n=120) carotid stenosis underwent high-resolution plaque magnetic resonance imaging. Seventy-five patients had recent IPH (symptomatic, 33%; asymptomatic, 31%). In symptomatic stenosis, recent IPH was independently associated with degree of stenosis (odds ratio [OR]=4.21, 1.61-10.98 for North American Symptomatic Carotid Endarterectomy Trial >35%; OR=2.92, 1.18-7.24 for European Carotid Surgery Trial >60%), qualifying event (OR=4.13; 1.11-15.32 for stroke or hemispheric transient ischemic attack ≥1 hour versus transient ischemic attack <1 hour or ocular symptoms), time from ischemic event (OR=6.65, 1.56-28.35 for ≤2 weeks; OR=2.24, 0.87-5.81 for 2-12 weeks versus >12 weeks; P for trend=0.03). In asymptomatic stenosis, IPH was only associated with stenosis severity >70% by ECST (OR=6.65; 1.95-22.73) but not by the NASCET method., Conclusions: Our findings support the potential link between recent IPH and risk of ipsilateral stroke in symptomatic disease but also imply that prognostic studies should adjust for known stroke risk factors in multivariate analyses. In asymptomatic stenosis, the potential predictive value of recent IPH is less likely to be confounded by stroke risk factors.

Left visual neglect is a dramatic neurological condition that impairs awareness of left-sided events. Neglect has been classically reported after strokes in the territory of the right middle cerebral artery. However, the precise lesional correlates of neglect within this territory remain discussed. Recent evidence strongly suggests an implication of dysfunction of large-scale perisylvian networks in chronic neglect, but the quantitative relationships between neglect signs and damage to white matter (WM) tracts have never been explored. In this prospective study, we used diffusion tensor imaging (DTI) tractography in twelve patients with a vascular stroke in the right hemisphere. Six of these patients showed signs of neglect. Nonparametric voxel-based comparisons between neglect and controls on fractional anisotropy maps revealed clusters in the perisylvian WM and in the external capsule. Individual DTI tractography identified specific disconnections of the fronto-parietal and fronto-occipital pathways in the neglect group. Voxel-based correlation statistics highlighted correlations between patients' performance on two visual search tasks and damage to WM clusters. These clusters were located in the anterior limb of the internal capsule and in the WM underlying the inferior frontal gyrus, along the trajectory of the anterior segment of the arcuate fasciculus (asAF). These results indicate that chronic visual neglect can result from, and correlate with, damage to fronto-parietal connections in the right hemisphere, within large-scale cortical networks important for orienting of spatial attention, arousal and spatial working memory.

Purpose: To assess the value of magnetic resonance (MR) imaging parameters as surrogate markers of stroke duration., Materials and Methods: The study was approved by the Ethics Committee of Ile de France III and was found to conform to generally accepted scientific principles and ethical standards. The authors studied 130 patients with acute stroke of known onset time who underwent 1.5-T MR imaging within 12 hours of the onset of stroke symptoms. Fluid-attenuated inversion recovery (FLAIR), diffusion-weighted (DW) imaging, and apparent diffusion coefficient (ADC) ratios were computed by using three-dimensional regions of interest to outline signal intensity changes on DW images and then projecting them onto the contralateral hemisphere. Imaging ratios in 63 patients who underwent imaging 0-3 hours after symptom onset were compared with those in 67 patients who underwent imaging more than 3 hours after onset by using the Student t test and receiver operating characteristic curves. The accuracy (sensitivity, specificity, and 95% confidence intervals [CIs]) of lesion visibility on FLAIR images in the prediction of a stroke onset time of less than 3 hours was assessed by two independent observers., Results: Differences in imaging ratios between patients imaged 0-3 hours after symptom onset and those imaged more than 3 hours after onset were statistically significant (P < .001). The FLAIR ratio showed a positive correlation with the time from symptom onset (Pearson correlation coefficient, 0.63). Receiver operating characteristic curves indicated that the FLAIR ratio could reliably identify patients imaged 0-3 hours after symptom onset, reaching 90% sensitivity (95% CI: 83%, 98%) and 93% specificity (95% CI: 86%, 99%) when using a 7% cutoff. Stroke imaged within 3 hours could also be identified by means of visual inspection of FLAIR and DW MR images, with 94% sensitivity (95% CI: 88%, 100%) and 97% specificity (95% CI: 93%, 101%)., Conclusion: Signal intensity changes on 1.5-T FLAIR MR images can be used as a surrogate marker of stroke age, either qualitatively or quantitatively. This suggests that MR imaging might be used as a "clock" for determining stroke age in patients with an unknown onset time, potentially increasing the number of patients who are eligible for thrombolysis., (© RSNA, 2010.)

The multiplicity of meningiomas or abrupt lesion growth in patients treated with cyproterone acetate suggests that this progestative treatment may promote lesion growth. We report the rapid regression of an incidental meningioma after discontinuation of a 10-year cyproterone acetate treatment. This unique observation suggests that conservative management of meningiomas may be the best option among users of high doses of cyproterone acetate, given that spontaneous regression may occur after hormonal treatment discontinuation.

Purpose: To report clinical and imaging features of diffuse cerebral vasoconstriction and to discuss the role of non-invasive imaging modalities for the diagnosis and the follow-up., Patients and Methods: Retrospective study including 13 consecutive patients with a diffuse cerebral vasoconstriction. Evaluation of the sensitivity of Doppler US and magnetic resonance angiography for the diagnosis., Results: The diagnosis is based on the association of a thunderclap headache, declenching factors found in 50% of cases and of stenosis involving middle and small cerebra arteries. In some cases cerebral hemorrhage may be present., Discussion: Diffuse cerebral vasoconstriction is a rare cause of thunder clap headhache, which needs to exclude other causes such as subarchnoid hemorrhage from aneurysm rupture. Non contrast CT of the head, frequently normal, may be falsely reassuring. It is therefore necessary to further assess the cerebral arteries to exclude an aneurysm but also to detect the presence of stenoses that would suggest the diagnosis. Non-invasive imaging modalities (MRA and Doppler US) are favored for detection and follow-up of proximal lesions.

The emergence of high-resolution rapid imaging methods has enabled magnetic resonance (MR) imagers to noninvasively image the fine internal structure of cervical arterial walls. In this article, a comprehensive guide to performing high-resolution MR imaging of cervical arteries is provided, including the choice of coils, sequences, and imaging parameters, as well as tips for optimal image quality. Explanations and illustrations are given of using high-resolution MR imaging to quantify plaque volume, determine atherosclerotic plaque burden, depict plaque composition, and ultimately identify unstable plaque before it leads to a clinical event. Finally, the role of high-resolution MR imaging in the diagnosis of cervical dissection and inflammatory disease of the arterial wall is emphasized., ((c) RSNA, 2009.)

Patients with stroke on awakening are denied the potential benefit of thrombolysis on the grounds that the onset time is unknown. Relying on clinical and MR imaging to indicate the most appropriate treatment could be more rational. We report 2 cases of stroke with unknown onset time. In both cases, anamnesis and MR imaging indicated that we might still be within 6 hours from stroke onset, with salvageable tissue. Arterial recanalization was successfully performed in both cases.

Left unilateral neglect, a dramatic condition which impairs awareness of left-sided events, has been classically reported after right hemisphere cortical lesions involving the inferior parietal region. More recently, the involvement of long range white matter tracts has been highlighted, consistent with the idea that awareness of events occurring in space depends on the coordinated activity of anatomically distributed brain regions. Damage to the superior longitudinal fasciculus (SLF), linking parietal to frontal cortical regions, or to the inferior longitudinal fasciculus (ILF), connecting occipital and temporal lobes, has been described in neglect patients. In this study, four right-handed patients with right hemisphere strokes underwent a high definition anatomical MRI with diffusion tensor imaging (DTI) sequences and a pencil and paper neglect battery of tests. We used DTI tractography to visualise the SLF, ILF and the inferior fronto-occipital fasciculus (IFOF), a pathway running the depth of the temporal lobe, not hitherto associated with neglect. Two patients with cortical involvement of the inferior parietal and superior temporal regions, but intact and symmetrical fasciculi, showed no signs of neglect. The other two patients with signs of left neglect had superficial damage to the inferior parietal cortex and white matter damage involving the IFOF. These findings suggest that superficial damage to the inferior parietal cortex per se may not be sufficient to produce visual neglect. In some cases, a lesion to the direct connections between ventral occipital and frontal regions (ie, IFOF) may contribute to the manifestation of neglect by impairing the top down modulation of visual areas from the frontal cortex.

Despite advances in diagnosis and treatment, atherosclerosis remains the second cause of death in the world. Due to technical advances, high resolution MRI (HR-MRI) allows depiction of the wall of cervical arteries, especially carotid atherosclerosis. HR-MRI allows visualization of the different components of atherosclerosis: necrotic lipid core, intraplaque hemorrhage, calcifications and fibrous cap. Global plaque volume as well as the volumes of individual plaque components can be calculated. Atherosclerotic plaque structure analysis, along with stenosis measurement, contribute to the stratification of the stroke risk. HR-MRI may also be used to assess treatment efficacy aimed at stabilizing or reducing plaque progression. Beyond the arterial lumen, direct evaluation of vessel wall should modify the management of atherosclerosis in the years to come.

Background and Purpose: Our aim was to determine whether diffusion-weighted imaging (DWI) changes associated with transient ischemic attack (TIA) are reversible or correspond to permanent tissue injury., Methods: Among 103 consecutive patients admitted for TIA, 36 (34.9%) had abnormalities on initial DWI (delay from TIA = 30 +/- 33 hours [mean +/- SD]). Thirty-three patients (59 DWI lesions) had an MR imaging follow-up (delay from TIA = 10.6 +/- 5 months) including fluid-attenuated inversion recovery, T2, DWI, and 3D T1-weighted sequences. For each lesion, we recorded the quantitative parameters on initial DWI (volume, apparent diffusion coefficient [ADC]) and performed a comparison between reversible and irreversible lesions., Results: MR imaging failed to detect any permanent injury in 7 patients and identified subsequent infarct in regions corresponding to the original DWI abnormalities in 26 patients (79%). Of the 59 lesions initially identified on DWI, 45 (76.3%) were associated with permanent injury on follow-up MR imaging. The DWI volume was significantly larger (0.91 +/- 1.7 versus 0.21 +/- 0.21 cm(3), P = .003) and the ADC ratio values lower (79 +/- 15% versus 91 +/- 9%, P = .001) in lesions with subsequent infarct than in those that were fully reversible., Conclusion: By showing that most patients with DWI-positive TIAs share the same imaging outcome as stroke patients, our data provide additional support for the redefinition of TIA, which considers that all cases of transient deficit with characteristic neuroimaging abnormalities should be diagnosed as a stroke.

Cerebral venous thrombosis (CVT) can be difficult to diagnose because of its wide spectrum of clinical manifestations. Its diagnosis may be further complicated when patients initially present with acute subarachnoid hemorrhage (SAH). We report on four patients with SAH revealing a CVT and discuss the role of imaging for diagnostic and pretherapeutic workup. In three women and one man presenting with severe headaches, images initially suggested SAH with no associated parenchymal bleeding. In all patients, SAH involved the sulci of the convexity and spared the basal cisterns. Digital subtracted angiography showed occlusion of intracranial venous sinuses but did not reveal any other cause of SAH. All patients improved with anticoagulant therapy. Risk factors for CVT and SAH, namely, head trauma and oral contraception, were identified in two patients. These cases highlight the fact SAH may reveal a CVT, which should be considered in the diagnostic workup of SAH, especially when the basal cisterns are not involved.

The authors report the case of a 38-year-old woman with a cavernous DAVF resulting in edematous lesions located in the territory of the ipsilateral basal vein. Transarterial embolization led to subtotal regression of the fistula associated with the regression of cerebral abnormalities. The authors discuss the pathophysiology of the cerebral edematous lesions and the therapeutic consequences according to the venous drainage of the cavernous sinus., (Copyright 2004 Masson, Paris)

The terms posterior reversible leukoencephalopathy, reversible posterior cerebral edema syndrome, and posterior reversible encephalopathy syndrome (PRES) all refer to a clinicoradiologic entity characterized by headaches, confusion, visual disturbances, seizures, and posterior transient changes on neuroimaging. Clinical findings are not sufficiently specific to readily establish the diagnosis; in contrast, magnetic resonance imaging pattern is often characteristic and represents an essential component of the diagnosis of PRES. Typical lesions predominate in the posterior white matter, with some involvement of the overlying cortex; are hyperintense on T2-weighted images; and are usually hypointense or isointense on diffusion-weighted images, with an increase of the apparent diffusion coefficient, indicating vasogenic edema. The pathogenesis is incompletely understood, although it seems to be related to the breakthrough of autoregulation and endothelial dysfunction. Since its initial description, this syndrome has been subsequently described in an increasing number of medical conditions, including hypertensive encephalopathy, eclampsia, and the use of cytotoxic and immunosuppressive drugs. The diagnosis has important therapeutic and prognostic implications because the reversibility of the clinical and radiologic abnormalities is contingent on the prompt control of blood pressure and/or discontinuing the offending drug. On the contrary, when unrecognized, conversion to irreversible cytotoxic edema may occur.

Diffusion tensor imaging allows a 3D analysis of water molecular motion and an exploration of white matter tracts integrity and orientation. We report a diffusion tensor study of wallerian degeneration of the corticospinal tract following a capsulo-lenticular hemorrhage in a 49-year old man. Reduced anisotropy (loss of fiber coherence) with preserved diffusivity of the damaged corticospinal tract was observed. This highlights the feasibility of diffusion tensor imaging on clinical MR units and its ability to quantify the degree of white matter tract destruction.

We report a case of 54 year old patient harboring a solitary painless mass of the calvarium. There was a well-defined biparietal lytic lesion on plain skull radiographics. Computed tomography showed a large hyperdense lesion. This lesion was extraaxial and nearly isointense with gray matter on T1 and T2-weighted MR images, and diffusely enhanced after gadolinium injection. Angiography showed hyperovascularity supplied by middle meningeal and superficial temporal arteries. Imaging study bore some similarities to meningioma. A large extra-axial mass with an important lytic lesion should have led to the diagnosis of plasmocytoma.

3D time-of-flight magnetic resonance angiography (3D TOF MRA) and 2D MRA with presaturation were evaluated in 18 patients with 21 giant intracranial aneurysms. 3D TOF MRA gave optimal images of proximal unruptured and nonthrombosed aneurysms. 2D MRA with presaturation was more informative in cases of distal, haemorrhagic or thrombosed aneurysms and in assessment of their components (thrombus, haemorrhage, patent residual lumen).