Embolic Lesions Research Articles

Acute stroke after carotid endarterectomy: time for a paradigm shift? Multicenter experience with emergent carotid artery stenting with or without intracranial tandem occlusion thrombectomy.

Stroke in the immediate postoperative period after carotid endarterectomy is a rare complication. Many centers have begun incorporating angiography before surgical re-exploration, which has the advantage of confirming carotid occlusion and treating tandem intracranial lesions if present. To determine the safety and efficacy of this strategy. A retrospective review was performed of all patients undergoing acute stenting of the carotid artery after carotid endarterectomy from November 2009 to June 2013 at 4 centers. Charts and angiographic images were reviewed. Eleven cases of carotid thrombosis within 72 hours of carotid endarterectomy and subsequent treatment strategies are summarized. All patients had >50% carotid stenosis before carotid endarterectomy. One patient had intraoperative occlusion and dissection of the internal carotid artery, which was noted on intraoperative carotid duplex ultrasound. All patients underwent postoperative computed tomography or computed tomography perfusion scans with subsequent cerebral angiography and stent reconstruction within 11 hours of symptom onset. In all cases, carotid recanalization was successfully completed between 32 and 160 minutes from groin puncture. There were no procedural complications. Four patients had a tandem middle cerebral artery occlusion, 3 of whom underwent successful recanalization. Emergent endovascular evaluation in the setting of acute post--carotid endarterectomy thrombosis is a safe and timely treatment option, with the benefit of detecting and treating embolic intracranial lesions. Immediate angiography and intervention in this rare surgical complication show promising initial results.

Incidence and Mechanisms of Cerebral Ischemia After Transcatheter Aortic Valve Implantation Compared With Surgical Aortic Valve Replacement

The most likely mechanisms of neurologic injury after transcatheter aortic valve implantation (TAVI) and aortic valve replacement (AVR) are cerebral embolization and hypoperfusion. We set out to determine potential mechanisms of neurologic injury after TAVI compared with AVR. One hundred twenty-seven consecutive high-risk patients with severe aortic stenosis (AS) who underwent TAVI (n= 85) or AVR (n= 42) were studied. Transcranial Doppler ultrasound (TCD), cerebral oximetry, diffusion-weighted magnetic resonance imaging (DW-MRI) (before, 6 days, and 3 months after procedure), and neurocognitive assessment before and at 3 months were performed. Neurologic injury was not significantly different between TAVI and AVR at 1 (1.1% vs 2.2%, p= 0.25) and 3 months (4.7% vs 2.2%, p= 1). At 3 months, overall cognitive score was higher in AVR compared with TAVI when adjusted for baseline score; the estimated difference between groups was 0.63 (95% confidence interval 0.87% to 1.17%; p= 0.02). Cerebral embolic load was 212 (123 to 344) during AVR and 134 (76 to 244) during TAVI (p= 0.07). Cerebral oxygen desaturation during AVR (7.56 ± 2.16) was higher compared with TAVI (5.93 ± 2.47) (p < 0.01). Ischemic lesions measured by DW-MRI occurred in 76% of TAVI and 71% of AVR patients at 6 days (p= 0.69) and 63% and 39% at 3 months (p= 0.11). No significant association was found between cerebral emboli, cerebral oxygen desaturation, brain ischemic lesions, and general cognitive score. At 3 months follow-up, overall cognitive score was higher in AVR compared with TAVI, adjusted for baseline score. However, there was no difference in cerebral embolic load, ischemic lesions, and oxygen desaturation.

Effect of coronary artery bypass grafting surgery with a pump on cerebral blood flow in high-risk patients

Coronary artery bypass grafting (CABG) surgery usually improves myocardial contractility, reducing cardiovascular events. However, it is a high-risk procedure associated with significant neurological complications, including stroke, delirium and cognitive impairment. The pathophysiology of these complications is not very well known, and may include low flow state after surgery, low cardiac output, embolism and reperfusion lesion. The aim of this study is to prospectively evaluate the cerebral hemodynamics through transcranial color and spectral Doppler sonography in high-risk patients undergoing cardiac surgery with a pump.

Abstract 12920: The Value of 18 FDG PET/CT in the Diagnostic Work-Up of Patients With Possible Infective Endocarditis

The diagnosis of infective endocarditis (IE) is sometimes difficult when there are discrepancies between blood cultures, transesophageal echocardiography (TEE) and clinical judgment. The aim of this study was to assess the incremental diagnostic value of 18 F-FDG-PET/CT in 45 consecutive patients (73% male, mean age 61 ± 26 years) with suspected IE and inconclusive tests at admission. In 28 patients (19 with a cardiac valvular (15) or nonvalvular (4) device) with blood cultures positive for germs typically involved in IE the initial TEE was negative or inconclusive. In 10 patients presenting with fever TEE identified cardiac lesion possibly related to IE (ruptured mitral chordae, thickened valve leaflet, thickened prosthetic annulus), but blood cultures were persistently negative. Finally, 7 patients had metastatic or embolic lesions and a predisposing cardiac condition, but TEE was negative. When previous unknown lesions detected by PET/CT were confirmed by succeeding examinations, they were considered true positives. When PET/CT was negative, it was compared with the final diagnosis that was defined according to the modified Duke criteria determined during a 6-month follow-up. Thirty patients had definite IE at the end of the follow-up, 3 had possible IE, and in 12 patients the diagnosis was rejected. Twenty-seven patients (60%) exhibited abnormal FDG uptake around the cardiac valves, and 12 (27%) had extracardiac accumulation. In 5 patients the initial negative TEE became positive a mean 5 ±7 days after PET/CT had been performed The sensitivity, specificity, positive predictive value, and negative predictive value of PET/CT were as follows (95% confidence interval): 87% (68% to 95%), 67% (38% to 87%), 84% (65% to 94%), and 71% (42% to 92%), respectively. Adding abnormal FDG uptake as a new major criterion significantly increased the sensitivity of the modified Duke criteria at admission (68% [53% to 82%] vs. 96% [88% to 99%], p = 0.01). This result was due to a significant reduction (p &lt; 0.001) in the number of possible IE cases. In conclusion PET/CT increases the diagnostic accuracy for IE in the subset of patients with possible IE and may help to manage a challenging situation.

Cerebral embolic lesions detected with diffusion-weighted magnetic resonance imaging following carotid artery stenting: a meta-analysis of 8 studies comparing filter cerebral protection and proximal balloon occlusion.

The aim of this meta-analysis was to evaluate and compare the efficacy of the 2 different neuroprotection systems in preventing embolization during carotid artery stenting (CAS), as detected by diffusion-weighted magnetic resonance imaging (DW-MRI). Data from randomized and nonrandomized studies comparing both types of embolic protection devices revealed contrasting evidence about their efficacy in neuroprotection, as assessed by the incidence of new ischemic lesions detected by DW-MRI. Eight studies, enrolling 357 patients, were included in the meta-analysis. Our study analyzed the incidence of new ischemic lesions/patient, comparing filter cerebral protection and proximal balloon occlusion. Following CAS, the incidence of new ischemic lesions/patient detected by DW-MRI was significantly lower in the proximal balloon occlusion group (effect size [ES]:-0.43; 95% confidence interval [CI]:-0.84 to-0.02, I(2)= 70.08, Q= 23.40). Furthermore, following CAS, the incidence of lesions at the contralateral site was significantly lower in the proximal protection group (ES:-0.50; 95% CI:-0.72 to-0.27, I(2)= 0.00, Q= 3.80). Our meta-analysis supports the concept that the use of proximal balloon occlusion compared with filter cerebral protection is associated with a reduction of the amount of CAS-related brain embolization. The data should be confirmed by a randomized clinical trial.

P-020 Emergent Carotid Artery Stenting with or without Intracranial Tandem Occlusion Lesions Following Carotid Endarterectomy

IntroductionStroke in the immediate post-operative period following carotid endarterectomy (CEA) is usually due to carotid thrombosis. Many centers have begun incorporating angiography before re-exploration, which has the advantage of confirming...

Abstract T P92: Paraoxonase Gene Polymorphism and Carotid Atherosclerosis in Acute Ischemic Stroke

Background: Atherosclerosis in the carotid artery is one of the main causes of acute ischemic stroke. Lipid oxidation has been known to play an important role in the pathogenesis of atherosclerosis. Paraoxonase (PON) is involved in lipid oxidation and has anti-atherogenic activity. PON single-nucleotide polymorphism (SNP) is associated with serum concentration, the activity of paraoxonase, and an increased risk of vascular disease. The purpose of this study was to investigate the association between four genetic variations of PON SNPs and carotid atherosclerosis (CA) in Korean stroke patients. Methods: Acute stroke patients with cardioembolism, other etiologies, and undermined etiologies were excluded to avoid mistaking embolic occlusive lesion for true atherosclerotic lesion. We included 656 subjects who met the inclusion criteria among acute ischemic stroke patients. One hundred and eighty-six subjects had LAA subtype of stroke, and 468 had SVO stroke. All subjects were categorized four subgroups based on the angiographic findings as follows: (1) the No ECIC+ICIC group (those without significant stenosis in the intracranial and extracranial carotid arteries); (2) the ECIC group (those with significant stenosis in the extracranial carotid arteries, but with no significant stenosis in the intracranial carotid arteries); (3) the ICIC group (those with significant stenosis in the intracranial carotid arteries, but with no significant stenosis in the extracranial carotid arteries); and (4) the ECIC+ICIC group (those with significant stenosis in the intracranial and extracranial carotid arteries). All enrolled patients were genotyped with the four genetic variations of PON SNPs (PON1 L55M, PON1 Q192R, PON2 A1148G, and PON2 C311S). Results: There were no significant associations between the four PON SNPs of each subgroups according to CA. In cases of LAA stroke, patients with CA had a significantly higher frequency of the PON2 148 AA and PON2 311 CC genotype than those without CA (p=0.021). Conclusion: We found an association between PON SNPs and carotid atherosclerosis in LAA stroke. But there was no significant difference in distributions of PON SNPs between intracranial CA and extracranial CA.

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Silent Cerebral Embolism during Atrial Fibrillation Ablation:Pathophysiology, Prevention and Management.

Although many efforts have been directed to improve atrial fibrillation transcatheter ablation safety, thromboembolism to the brain remains one of the major complications. In fact several studies have confirmed occurrence of silent cerebral embolic lesions by post-procedure magnetic resonance imaging. The present review will focus on the possible mechanisms leading to silent cerebral embolism in an attempt to provide recommendations holding the potential to reduce the incidence of this clinically relevant complication.

Effect of antiplatelet therapy on thromboembolism after flow diversion with the Pipeline Embolization Device

Flow-diverting stents offer a novel treatment approach to intracranial aneurysms. Data regarding the incidence of acute procedure-related thromboembolic complications following deployment of the Pipeline Embolization Device (PED) remain scant. The authors sought to determine the rate of embolic events in a bid to identify potential risk factors and assess the role of platelet inhibition. Data in all patients receiving a PED for treatment of an intracranial aneurysm were prospectively maintained in a database. Diffusion-weighted 3-T MRI was performed within 24 hours of PED deployment. The incident rate of procedural embolism was established, and univariate analysis was then performed to determine any associations of embolic events with measured variables. The degree of platelet inhibition in response to aspirin and clopidogrel was evaluated by challenging the platelet samples with arachidonic acid and adenosine diphosphate, respectively, and then performing formal light transmission platelet aggregometry. Twenty-three patients with 26 aneurysms were eligible for inclusion in the study. Thirty-one PEDs were deployed in 25 procedures. All ischemic lesions detected on diffusion-weighted 3-T MRI were identified as embolic based on their location and distribution, with none appearing to be due to perforator artery occlusion. Procedural embolic events were found in the target parent vessel territory in 13 (52%) of 25 procedures, with no patients harboring lesions contralateral to the deployed PED. The number of embolic events per procedure ranged from 3 to 16, with a mean of 5.4. There was no significant difference between cases with and without procedural embolism in platelet inhibition by aspirin (mean 15% vs 12% residual activation; p = 0.28), platelet inhibition by clopidogrel (mean 41% vs 41% residual activation; p = 0.98), or intraprocedural heparin-induced anticoagulation (mean activated clotting time 235 seconds vs 237 seconds; p = 0.81). By multivariate analysis, the authors identified larger aneurysm size (p = 0.03) as the single variable significantly associated with procedural embolism. There was no significant relationship between aneurysm size and the number of embolic events (p = 0.32) or the total burden of the embolism lesion area (p = 0.53). Acute embolism following use of the PED for treatment of intracranial aneurysms is more common than hypothesized. The only identifiable risk factor for embolism appears to be greater aneurysm size, perhaps indicating significant disturbed flow across the aneurysm neck with ingress and egress through the PED struts. The strength of antiplatelet therapy, as measured by residual platelet aggregation, did not appear to be associated with cases of procedural embolism. Further work is needed to determine the implications of these findings and whether anticoagulation regimens can be altered to lower the rate of complications following PED deployment.

Risk factors for ipsi- and contralateral cerebral ischemic lesions after carotid artery stenting with embolic protection

Objective: We aimed to identify factors predictive for new ipsi- and contralateral cerebral ischemic lesions during embolic protected carotid artery stenting (CAS). Background: Carotid endarterectomy and CAS appear to have similar overall perioperative stroke rates, which, however, may differ in specific patient subgroups. Knowledge of the risk factors for cerebral embolic events during CAS may impact treatment decisions for the individual patient, but have not been extensively studied. Aim of the study: To evaluate the risk factors for cerebral embolization after carotid artery stenting with embolic protection. Methods: Out of 837 consecutive patients undergoing CAS with cerebral embolic protection pre- and post-procedural diffusion weighted magnetic resonance imaging (DW-MRI) was performed for evaluation of new cerebral ischemic lesions in 728 patients (86.9%). Multivariate logistic regression analyses were performed to identify factors predictive for embolic events. Results: New ischemic lesions were found in 32.8% of the patients. Age, hypertension, lesion length, lesion excentricity, and aortic arch type III were significantly associated with new ischemic lesions, calcified lesions were negatively associated. In 25% of patients with embolic events lesions were also found in the contralateral hemisphere. Predictive factors for contralateral lesions were age, > 50% stenosis of the contralateral internal carotid artery, and an aortic arch type II, with a trend for aortic arch type III. Conclusions: Age, hypertension, lesion morphology, and aortic arch type were predictive for procedural related cerebral embolic events during embolic protected CAS. Age, significant contralateral carotid stenosis and complex aortic arch type were predictive for contralateral ischemic events. These findings may help to find the optimal treatment decision for the individual patient with carotid artery stenosis.

Anatomical localization and progression of silent cerebral embolic lesions following transcatheter ablation of atrial fibrillation

Anatomical localization and progression of silent cerebral embolic lesions following transcatheter ablation of atrial fibrillation

Asymptomatic Cerebral Embolism and Atrial Fibrillation Ablation

Radiofrequency catheter ablation of symptomatic arrhythmias has enjoyed unprecedented growth during the past 2 decades. This has been attributed to its high success rate in the treatment of a variety of arrhythmias with a discrete ablation target and the low complication rate observed in these procedures.1,2 Initial investigators performing radiofrequency catheter ablation were fortunate that the lesions created with this energy source were small and discrete. It was difficult to cause excessive collateral injury. Early recognition of the problem of sudden electric impedance rise and coagulum formation3 led to a number of strategies and technologies to minimize this occurrence. In contrast to supraventricular tachycardia ablation, catheter ablation of atrial fibrillation has pushed the limits of our ablation technologies and has shifted the ratio of efficacy to risk in an unfavorable direction.4 Aggressive ablation with extensive linear ablation, ablation of complex fractionated atrial electrograms, and empirical isolation (debulking) of the posterior left atrial wall5 have improved procedural success in patients with persistent atrial fibrillation. But with a greater volume of myocardial injury and a greater surface area of disrupted left atrial endocardium from the ablation, it is not surprising that procedure-related complications, especially embolic complications, are more prevalent. Article see p 473 The initial observations of the appearance of new asymptomatic cerebral embolism (ACE) lesions on diffusion-weighted MR imaging scans after radiofrequency catheter ablation of atrial fibrillation were striking6,7 but should not have been unanticipated. The ACE lesions observed are attributed to cerebral microembolism and have been widely reported after procedures, such as cardiopulmonary bypass,8 carotid artery stenting,9 and trans aortic valve replacement.10 The fact that ACE lesions have not been reported previously with radiofrequency ablation either has been because of good fortune or simply …

Risk Factors for Cerebral Embolization After Carotid Artery Stenting With Embolic Protection

Meta-analyses of randomized trials have shown an increased risk of periprocedural stroke after carotid artery stenting (CAS) compared with carotid endarterectomy, which may differ in specific patient subgroups. Knowledge of risk factors for cerebral embolic lesions during CAS may impact treatment decisions for the individual patient, but these factors have not been extensively studied. We aimed to identify factors predictive for cerebral ischemic lesions during embolic protected CAS. Preprocedural and postprocedural diffusion-weighted magnetic resonance imaging was performed for evaluation of new cerebral ischemic lesions in 728 (86.9%) of 837 consecutive patients undergoing CAS with cerebral embolic protection. Multivariable logistic regression analyses were performed to identify factors predictive for embolic lesions. New ischemic lesions were found in 32.8% of patients. Age, hypertension, lesion length, lesion eccentricity, and aortic arch type III were significantly associated with new ischemic lesions; calcified lesions were negatively associated. In 25% of these patients embolic lesions were also found in the contralateral hemisphere. Predictive factors for contralateral lesions were age, >50% stenosis of the contralateral internal carotid artery, and an aortic arch type II, with a trend for aortic arch type III. Age, hypertension, lesion morphology, and aortic arch type were predictive for procedural-related cerebral embolic lesions during embolic protected CAS. Age, significant contralateral carotid stenosis, and complex aortic arch type were predictive for bilateral ischemic lesions. The clinical implications of ischemic lesions are not yet fully understood.

144 A CEREBRAL DIFFUSION WEIGHTED MRI STUDY TO ASSESS THE DIFFERENCE BETWEEN EMBOLIC EVENTS FOLLOWING TRANSCATHETER AORTIC VALVE IMPLANTATION (TAVI) AND SURGICAL AORTIC VALVE REPLACEMENT (SAVR)

<h3>Background</h3> Transcatheter Aortic Valve Implantation (TAVI) is used to treat symptomatic severe aortic stenosis in a non-surgical high risk population. The incidence of stroke and micro-infarction is higher in the TAVI population compared to surgical aortic valve replacement (SAVR), which may be due to various factors, including valve calcification and aortic atheroma. However, the natural history and clinical consequences of ‘silent’ micro-infarction is unknown. <h3>Methods</h3> Cerebral imaging was conducted pre-TAVI/SAVR, at &lt;7 days post-procedure and at 6 months. MRI scans were performed on a 1.5 T system (Intera, Philips or Avanto, Siemens) using a protocol of T2 weighted fast field echo, T2 turbo field echo and diffusion weighted imaging (DWI) (22 slices, 5 mm thick, 1mm gap, FOV 350, RFOV 100). Three neuroradiologists independently analysed the scans and were blinded to all clinical details to avoid bias. New cerebral lesions were quantified (ml of cerebral tissue) and the vascular territory described. Quantification of cerebral infarct lesion volume was performed by manual planimetry using post processing software (Qmass 7.2 Medis, The Netherlands). <h3>Results</h3> 45 TAVI and 21 SAVR patients were studied. Mean age for TAVI was 80±5.9 years, for SAVR 69±8.8 years: Logistic EuroSCORE for TAVI was 19.1±13, for SAVR 7.1±2.7. In the TAVI patients 82% had new embolic lesions on DWI (figure&nbsp;1), compared to 47.6% of the SAVR group. Two TAVI patients had a clinical stroke compared to none in the SAVR group. There was a higher cerebral infarct lesion volume in TAVI group compared to SAVR group (1.74±2.8 ml vs 0.41±0.48 ml p=0.01). At 6 months 17 TAVI patients (11 were unable to attend, 10 had died, 7 had a pacemaker) and 18 SAVR (1 died and 1 was unable to attend) were re-scanned. Only 1 TAVI and 1 SAVR patient had a new subclinical micro-infarct. All previously detected micro-infarcts had completely resolved. <h3>Conclusions</h3> There is a significantly greater number of new micro-embolic events after TAVI compared to SAVR. However all of these lesions appear to completely resolve on DWI MRI by 6 months. <h3>Funding</h3> SP is funded by a British Heart Foundation fellowship (FS/10/62/28409). SP and JPG receive an educational research grant from Philips Healthcare.

Clinical implications for diffusion‐weighted MRI brain lesions associated with transcatheter aortic valve replacement

Transcatheter aortic valve replacement (TAVR) is increasingly used to treat patients with aortic stenosis deemed high or extreme surgical risk candidates. Despite improved survival and quality of life following the procedure, TAVR is not without its complications. Stroke is a major source of morbidity and mortality in patients undergoing the procedure, with rates similar to and often higher than those associated with surgery. Most studies show a consistent link between TAVR and embolic lesions visualized on diffusion-weighted magnetic resonance imaging. The question of whether these lesions lead to long-term cognitive consequences remains open, but given the large literature on silent strokes and cognition, this association is probable. Initial studies implementing cerebral embolic protection devices in TAVR have yielded promising results with decreased neurological complications and appearance of new lesions on imaging. In this article, we will review the evidence linking silent stroke with cognitive decline, and potential therapeutic options to prevent stroke related to TAVR, including cerebral protection devices currently under investigation.

Contemporary outcomes after distal vertebral reconstruction

Flow-limiting lesions or embolic phenomena can produce vertebrobasilar ischemia. This study aims to differentiate the pathophysiology of vertebral ischemia and examine contemporary outcomes after distal vertebral reconstruction. Between February 2005 and November 2011, 41 consecutive distal vertebral artery (VA) reconstructions were performed in 34 patients, including bypass to the third portion of the VA (V3) at the C1-2 level (n = 24) or the C0-1 level (n = 7); transposition of the external carotid artery or its occipital branch onto V3 (n = 6); transposition of V3 onto the internal carotid artery (n = 3); and bypass from the ipsilateral subclavian artery to V3 (n = 1). Six patients required a concomitant carotid intervention, and nine patients required a partial resection of the C1 transverse process. Symptoms, present in 91% of patients, were attributed to a flow-limiting lesion in 16 (52%), to embolization in nine (29%), and to a mixed etiology in six (19%). Intraoperatively, five patients required graft revision or conversion of a transposition to a bypass, and two patients required vertebral ligation. Median blood loss was 260 mL. Median hospital length of stay was 1 day. Postoperatively, one patient (2%) required re-exploration for bleeding, a stroke occurred in one patient (2%), and cranial nerve injury occurred in three patients (7%). There were no perioperative deaths. Survival analysis showed that primary patency at 1, 2, and 5 years, respectively, was 74%, 74%, and 54%. Secondary patency was 80% at 1 year and remained so through the end of follow-up at 80 months. A statistically significant difference in patency was noted favoring arterial transposition over vertebral bypass of 100%, 100%, and 83% at 1, 2, and 5 years, respectively, vs 65%, 65%, and 39% (P = .018). Considering successful redo bypass grafting for late failure, 97% of patients demonstrated preserved patency at their last follow-up. There were two late deaths of unknown etiology and no late strokes. Distal VA reconstruction for flow-limiting or embolic lesions provides excellent stroke protection and symptomatic relief with acceptable perioperative risk in selected patients.

Perplexing Imaging Manifestations of Multiple Metastatic Intracranial Lesions Associated With Atrial Myxoma

Neurological manifestations of atrial myxomas may be encountered in different pathological circumstances: cerebral embolism, intracranial aneurysms, and metastatic mass lesions. We report a case of multiple metastatic intracranial lesions associated with atrial myxoma and discuss the potential mechanisms of its perplexing neuroimaging manifestations. Comparing with previous reports of myxoma-associated intracranial lesions, the most notable features of the present case were the multiple high-density "calcified" lesions accompanying the aneurysms on computed tomography scan and the significant contrast-enhanced mass in the left parietal lobe on magnetic resonance scan. This suggested an extremely rare case of coexistence of aneurysms and intracranial metastatic mass lesion associated with cardiac myxoma, although the pathological evidence was not available.

Complete Early Reversal of Diffusion-Weighted Imaging Hyperintensities After Ischemic Stroke Is Mainly Limited to Small Embolic Lesions

Case reports have demonstrated complete early reversal of hyperintensities on diffusion-weighted imaging (DWI) after clinically diagnosed stroke. We aimed to investigate systematically the rate and characteristics of reversible diffusion hyperintensities (RDHs) in the first week after stroke. Patients with clinical diagnosis of an acute cerebrovascular event and evidence of ischemia on DWI were included. MRI scans were performed on admission, on the following day, and 4 to 7 days after onset of symptoms with DWI and fluid-attenuated inversion recovery. Baseline and follow-up DWIs were coregistered and examined for individual RDHs. Characteristics of patients and of hyperintensities associated with early reversal were identified. We included 153 patients with a median National Institutes of Health Stroke Scale score of 4 (interquartile range, 2-8). In 3 patients (2%), MR images normalized completely. Thirty-seven patients (24%) displayed individual RDHs. Of 611 initial DWI hyperintensities, 97 (16%) reversed. Thirteen percent of the RDHs had corresponding abnormalities on fluid-attenuated inversion recovery images at the third measurement. Median size of the RDHs was 0.029 mL (interquartile range, 0.013-0.055). RDHs were associated with a multiple infarct pattern (odds ratio, 22.1; 95% confidence interval, 4.5-109.7) and symptomatic carotid stenosis (odds ratio, 5.5; 95% confidence interval, 1.4-21.5). Fifty-nine percent of the patients with RDHs had new additional lesions on follow-up DWI. RDHs were not associated with functional improvement on the National Institutes of Health Stroke Scale score. In this population of mainly minor to moderate stroke patients, complete normalization of MR images was rare. Complete reversal of individual DWI hyperintensities was limited to very small lesions and mostly occurred in embolic stroke patients. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00715533.

First indication of gas embolism in a harbour porpoise (Phocoena phocoena) from German waters

In the last decade, a number of cetacean strandings have gas embolic pathology analogous to decompression sickness in man and experimental animals. Acute gas and fat embolic lesions have also been found in mass-stranded beaked whales causally linked to high-intensity anthropogenic mid-frequency sonar activities. Sporadic chronic gas embolic lesions have also been described. This communication describes a first case of numerous gas-filled fibrous cavities in the markedly enlarged liver of a dead adult male harbour porpoise stranded at the North Sea coast of Schleswig-Holstein, Germany. Additional pathological findings consisted of chronic parasitic granulomatous cholangiohepatitis, hepatic vein thrombosis, parasitic infestations of the bronchial tree and pulmonary blood vessels associated with bronchopneumonia and severe parasitic burden in both ear sinuses. The hepatic cavernous lesions are similar to those described in chronic gas bubble disease in other cetaceans, most likely resulting from decompression-related tissue supersaturation with nitrogen.