Neuroradiological findings expand the phenotype of OPA1-related mitochondrial dysfunction

OBJECTIVE

OPA1 mutations are responsible for more than half of autosomal dominant optic atrophy (ADOA), a blinding disease affecting the retinal ganglion neurons. In most patients the clinical presentation is restricted to the optic nerve degeneration, albeit in 20% of them, additional neuro-sensorial symptoms might be associated to the loss of vision, as frequently encountered in mitochondrial diseases. This study describes clinical and neuroradiological features of OPA1 patients.

METHODS

Twenty two patients from 17 families with decreased visual acuity related to optic atrophy and carrying an OPA1 mutation were enrolled. Patients underwent neuro-ophthalmological examinations. Brain magnetic resonance imaging (T1, T2 and flair sequences) was performed on a 1.5-Tesla MR Unit. Twenty patients underwent 2-D proton spectroscopic imaging.

RESULTS

Brain imaging disclosed abnormalities in 12 patients. Cerebellar atrophy mainly involving the vermis was observed in almost a quarter of the patients; other abnormalities included unspecific white matter hypersignal, hemispheric cortical atrophy, and lactate peak. Neurological examination disclosed one patient with a transient right hand motor deficit and ENT examination revealed hearing impairment in 6 patients. Patients with abnormal MRI were characterized by: (i) an older age (ii) more severe visual impairment with chronic visual acuity deterioration, and (iii) more frequent associated deafness.

CONCLUSIONS

Our results demonstrate that brain imaging abnormalities are common in OPA1 patients, even in those with normal neurological examination. Lactate peak, cerebellar and cortical atrophies are consistent with the mitochondrial dysfunction related to OPA1 mutations and might result from widespread neuronal degeneration.

Patient selection for stroke endovascular therapy--DWI-ASPECTS thresholds should vary among age groups: insights from the RECOST study

BACKGROUND AND PURPOSE

The purpose of this study was to evaluate the benefits of endovascular intervention in large-vessel occlusion strokes, depending on age class.

MATERIALS AND METHODS

A clinical management protocol including intravenous treatment and mechanical thrombectomy was instigated in our center in 2009 (Prognostic Factors Related to Clinical Outcome Following Thrombectomy in Ischemic Stroke [RECOST] study). All patients with acute ischemic stroke with an anterior circulation major-vessel occlusion who presented within 6 hours were evaluated with an initial MR imaging examination and were analyzed according to age subgroups (younger than 50 years, 50-59 years, 60-69 years, 70-79 years; 80 years or older). The mRS score at 3 months was the study end point.

RESULTS

One hundred sixty-five patients were included in the analysis. The mean age was 67.4 years (range, 29-90 years). The mean baseline NIHSS score was 17.24 (range, 3-27). The mean DWI-derived ASPECTS was 6.4. Recanalization of TICI 2b/3 was achieved in 80%. At 3 months, 41.72% of patients had a good outcome, with a gradation of prognosis depending on the age subgroup and a clear cutoff at 70 years. Only 19% of patients older than 80 years had a good outcome at 3 months (mean ASPECTS = 7.4) with 28% for 70-79 years (mean ASPECTS = 6.8), but 58% for 60-69 years (mean ASPECTS = 6), 52% for 50-59 years (mean ASPECTS = 5.91), and 72% for younger than 50 years (mean ASPECTS = 6.31). In contrast, the mortality rate was 35% for 80 years and older, and 26% for 70-79 versus 5%-9% for younger than 70 years.

CONCLUSIONS

The elderly may benefit from thrombectomy when their ischemic core volume is low in comparison with younger patients who still benefit from acute recanalization despite larger infarcts. Stroke volume thresholds should, therefore, be related and adjusted to the patient's age group.

Extra-aneurysmal flow modification following pipeline embolization device implantation: focus on regional branches, perforators, and the parent vessel

BACKGROUND AND PURPOSE

Flow-diverter technology has proved to be a safe and effective treatment for intracranial aneurysm based on the concept of flow diversion allowing parent artery and collateral preservation and aneurysm healing. We investigated the patency of covered side branches and flow modification within the parent artery following placement of the Pipeline Embolization Device in the treatment of intracranial aneurysms.

MATERIALS AND METHODS

Sixty-six aneurysms in 59 patients were treated with 96 Pipeline Embolization Devices. We retrospectively reviewed imaging and clinical results during the postoperative period at 6 and 12 months to assess flow modification through the parent artery and side branches. Reperfusion syndrome was assessed by MR imaging and clinical evaluation.

RESULTS

Slow flow was observed in 13 of 68 (19.1%) side branches covered by the Pipeline Embolization Device. It was reported in all cases of anterior cerebral artery coverage, in 3/5 cases of M2-MCA coverage, and in 5/34 (14.7%) cases of ophthalmic artery coverage. One territorial infarction was observed in a case of M2-MCA coverage, without arterial occlusion. One case of deep Sylvian infarct was reported in a case of coverage of MCA perforators. Two ophthalmic arteries (5.9%) were occluded, and 11 side branches (16.2%) were narrowed at 12 months' follow-up; patients remained asymptomatic. Parent vessel flow modification was responsible for 2 cases (3.4%) of reperfusion syndrome. Overall permanent morbidity and mortality rates were 5.2% and 6.9%, respectively. We did not report any permanent deficit or death in case of slow flow observed within side branches.

CONCLUSIONS

After Pipeline Embolization Device placement, reperfusion syndrome was observed in 3.4%, and territorial infarction, in 3.4%. Delayed occlusion of ophthalmic arteries and delayed narrowing of arteries covered by the Pipeline Embolization Device were observed in 5.9% and 16.2%, respectively. No permanent morbidity or death was related to side branch coverage at midterm follow-up.

Intracranial aneurysmal pulsatility as a new individual criterion for rupture risk evaluation: biomechanical and numeric approach (IRRAs Project)

BACKGROUND AND PURPOSE

The present study follows an experimental work based on the characterization of the biomechanical behavior of the aneurysmal wall and a numerical study where a significant difference in term of volume variation between ruptured and unruptured aneurysm was observed in a specific case. Our study was designed to highlight by means of numeric simulations the correlation between aneurysm sac pulsatility and the risk of rupture through the mechanical properties of the wall.

MATERIALS AND METHODS

In accordance with previous work suggesting a correlation between the risk of rupture and the material properties of cerebral aneurysms, 12 fluid-structure interaction computations were performed on 12 "patient-specific" cases, corresponding to typical shapes and locations of cerebral aneurysms. The variations of the aneurysmal volume during the cardiac cycle (ΔV) are compared by using wall material characteristics of either degraded or nondegraded tissues.

RESULTS

Aneurysms were located on 6 different arteries: middle cerebral artery (4), anterior cerebral artery (3), internal carotid artery (1), vertebral artery (1), ophthalmic artery (1), and basilar artery (1). Aneurysms presented different shapes (uniform or multilobulated) and diastolic volumes (from 18 to 392 mm3). The pulsatility (ΔV/V) was significantly larger for a soft aneurysmal material (average of 26%) than for a stiff material (average of 4%). The difference between ΔV, for each condition, was statistically significant: P=.005.

CONCLUSIONS

The difference in aneurysmal pulsatility as highlighted in this work might be a relevant patient-specific predictor of aneurysm risk of rupture.

Flow-diverter silk stent for the treatment of intracranial aneurysms: 1-year follow-up in a multicenter study

BACKGROUND AND PURPOSE

FD stent placement is a promising therapy for challenging intracranial aneurysms. Long-term evaluations about angiographic and morphologic results are still missing. This is the aim of this multicenter series.

MATERIALS AND METHODS

We report our experience and 1-year FU in a retrospective chart review of 65 consecutive subjects with 77 unruptured or recanalized aneurysms that were treated with Silk FD stents at 6 centers in France. Both angiographic and clinical results were recorded before treatment and at 6 and 12 months after treatment. At the 12-month FU, relationships between angiographic aneurysm occlusion and shrinkage of the thrombosed aneurysm sac were evaluated.

RESULTS

Stent deployment was achieved in 64 cases (98.5%) and failed in 1 case (1.5%). Seven misdeployments of the Silk stent caused the occlusion of 6 parent arteries. Overall acute/subacute procedural morbidity was 7.7%, and mortality was zero. Delayed complications were observed in 10.9% of subjects. At the 6-month FU, permanent morbidity was 7.8% and mortality was 3%. Complete occlusion occurred within 6 months in 68% of aneurysms and within 12 months after treatment in 84.5% of aneurysms. At the 12-month FU, in angiographically complete occluded aneurysms, MR imaging/CT analysis showed the complete disappearance of the thrombosed aneurysm in 30% of cases and partial shrinkage in 52%; furthermore, thrombosed aneurysms were stable in 11% of cases and enlarged in 7%.

CONCLUSIONS

The Silk stent is an effective tool for the treatment of challenging aneurysms because it allows complete occlusion in most cases 1 year after treatment. Permanent morbidity was 7.8%, and mortality was 3%.

Mid-term clinical and angiographic results of cerebral aneurisms treated with matrix2(®) coils

OBJECTIVE

To evaluate 1 year results of endovascular treatment (EVT) of intracranial aneurisms using Matrix second generation detachable coils (MSG(®)).

PATIENTS AND METHODS

Between January and December 2006, 32 patients with 32 intracranial aneurisms were treated by coiling using MSG(®), with a minimum follow-up of 1 year. Data were acquired prospectively. Exclusion criteria were: permanent adjunctive device, less than 50% MSG(®) length, and additional bioactive or coated coils. All procedures were carried out in a single institution. Six months and 1 year follow-up were performed with magnetic resonance angiography and digital subtraction angiography, respectively. We assessed radiological and clinical results using the modified Raymond classification, a 3-level longitudinal grading scale (LGS), Glasgow outcome and Rankin scales.

RESULTS

Thirteen (40.6%) male and 19 (59.4%) female underwent EVT using MSG(®) with a mean follow-up of 16.6 months. Ruptured aneurisms (75%) outnumbered unruptured. Immediate radiological results showed 15 complete occlusions (46.9%), 12 (37.5%) neck remnant, and five (15.6%) residual sac. In the mean time, six patients (18.7%) needed to be retreated due to insufficient initial packing or early recanalization. Using the LGS, a stable occlusion was observed in 40.7%, a progressive thrombosis in 25%, and 34.3% of the cases evolved unfavorably. Thirty-one patients had stable or improved clinical status, while one patient died from a thromboembolic event 1 month after retreatment (3.1% overall mortality).

CONCLUSION

At 1 year follow-up, MSG(®) demonstrated similar angiographic results compared to Matrix first generation coils and didn't suggest advantage over platinum coils.

Biomechanical wall properties of human intracranial aneurysms resected following surgical clipping (IRRAs Project)

BACKGROUND AND PURPOSE

Individual rupture risk assessment of intracranial aneurysms is a major issue in the clinical management of asymptomatic aneurysms. Aneurysm rupture occurs when wall tension exceeds the strength limit of the wall tissue. At present, aneurysmal wall mechanics are poorly understood and thus, risk assessment involving mechanical properties is inexistent. Aneurysm computational hemodynamics studies make the assumption of rigid walls, an arguable simplification. We therefore aim to assess mechanical properties of ruptured and unruptured intracranial aneurysms in order to provide the foundation for future patient-specific aneurysmal risk assessment. This work also challenges some of the currently held hypotheses in computational flow hemodynamics research.

METHODS

A specific conservation protocol was applied to aneurysmal tissues following clipping and resection in order to preserve their mechanical properties. Sixteen intracranial aneurysms (11 female, 5 male) underwent mechanical uniaxial stress tests under physiological conditions, temperature, and saline isotonic solution. These represented 11 unruptured and 5 ruptured aneurysms. Stress/strain curves were then obtained for each sample, and a fitting algorithm was applied following a 3-parameter (C(10), C(01), C(11)) Mooney-Rivlin hyperelastic model. Each aneurysm was classified according to its biomechanical properties and (un)rupture status.

RESULTS

Tissue testing demonstrated three main tissue classes: Soft, Rigid, and Intermediate. All unruptured aneurysms presented a more Rigid tissue than ruptured or pre-ruptured aneurysms within each gender subgroup. Wall thickness was not correlated to aneurysmal status (ruptured/unruptured). An Intermediate subgroup of unruptured aneurysms with softer tissue characteristic was identified and correlated with multiple documented risk factors of rupture.

CONCLUSION

There is a significant modification in biomechanical properties between ruptured aneurysm, presenting a soft tissue and unruptured aneurysms, presenting a rigid material. This finding strongly supports the idea that a biomechanical risk factor based assessment should be utilized in the to improve the therapeutic decision making.

Mechanical thrombectomy in acute ischemic stroke: catch device

BACKGROUND AND PURPOSE

Mechanical thrombectomy presents today a promising alternative to traditional stroke therapies. Our aim with this study was to evaluate the safety and efficacy of the Catch mechanical thrombectomy device in the treatment of acute stroke and report the angiographic results and clinical outcomes.

MATERIALS AND METHODS

We performed an analysis of 40 consecutive patients with ischemic stroke treated with the Catch device at our academic center. Forty patients were treated with the device: 25 with anterior circulation stroke and 15 with posterior circulation stroke. Thirty seven (92.5%) patients received an additional treatment to aid revascularization, including 36 patients treated with rtPA (mean dose of 35 mg).

RESULTS

The mean age was 63.5 years (range, 31-82 years; 55% men). The median NIHSS score at presentation was 18 (range, 3-38). The mean symptom-to-procedure start time was 440 minutes (range, 150-2637 minutes). Recanalization (TIMI 2-3) was achieved in 26/40 (65%). Symptomatic hemorrhage occurred in 18%. Procedural complications occurred in 6 patients without clinical consequences: 4 clot fragmentations and 2 vasospasms. Data were missing for 4 patients at 90 days. Ninety-day mortality was 41%; good 90-day functional outcome (mRS, ≤ 2) was achieved by 39% (14/36). Good neurologic outcomes at 90 days were more frequent (56.5% versus 7.7%), and mortality rates were lower (30% versus 61.5%) with successful compared with unsuccessful recanalization.

CONCLUSIONS

In our retrospective case series, the Catch device appears effective in achieving recanalization and improving 90-day outcome in patients with acute ischemic stroke.

Stent-assisted coiling of complex middle cerebral artery aneurysms: initial and midterm results

BACKGROUND AND PURPOSE

Clinical outcome and initial and midterm angiographic results of EVT of complex MCA aneurysms by using the stent-assisted coiling technique were retrospectively evaluated in our center where EVT of intracranial aneurysms is the first treatment option.

MATERIALS AND METHODS

From November 2003 to October 2009, 49 patients (27 men, 22 women; mean age, 52 ± 12 years) harboring 52 complex unruptured MCA aneurysms (11 ruptured previously and coiled but recanalized and 41 unruptured) were treated by EVT by using self-expandable intracranial stents. Procedural complications, clinical outcome, and initial and midterm angiographic results were evaluated. Initial treatment status and aneurysm sac size were tested as potential risk factors for recurrence.

RESULTS

After successful stent deployment, coiling was performed in 50 aneurysms (96.2%) in 47 patients; however, 2 failures (3.8%) occurred in 2 patients. Ten intrastent clot formations (20%) observed on final control angiography induced 2 permanent moderate disabilities (GOS score = 2). Mortality and permanent neurologic morbidity were 0% and 4.3%, respectively. At a mean period of 14 ± 9 months, among 48 aneurysms in 45 patients eligible for follow-up, 34 complete (71%) and 14 partial treatments (29%) were observed, 7 recurrences (14.6%) occurred, and 5 patients (10.4%) needed retreatment. No aneurysm bleeding or symptomatic intrastent stenosis was observed. Aneurysm sac size ≥7 mm and incomplete initial treatment were associated with more recurrences without a statistically significant difference.

CONCLUSIONS

For complex unruptured MCA aneurysms, EVT by using a self-expandable intracranial stent was feasible, safe, and durable and could be considered as the first-option treatment.

Multidisciplinary management of giant functional petrous bone paraganglioma

Giant and functional paragangliomas of the skull base are rare. Their endocrinological and surgical management is challenging. We report the case of an aggressive giant noradrenalin-secreting paraganglioma of the right temporal bone. Three procedures of embolisation were performed. The second one was complicated by a hypertensive crisis due to catecholamine release. The tumour was resected via a widened transcochlear approach. Tumour residue was treated by gamma knife radiosurgery, without additional growth at the last follow-up. This case illustrates the interest of multidisciplinary management of giant skull base paragangliomas.

Bilateral haemorrhagic infarction of the globus pallidus after cocaine and alcohol intoxication

Cocaine is a risk factor for both ischemic and haemorrhagic stroke. We present the case of a 31-year-old man with bilateral ischemia of the globus pallidus after excessive alcohol and intranasal cocaine use. Drug-related globus pallidus infarctions are most often associated with heroin. Bilateral basal ganglia infarcts after the use of cocaine, without concurrent heroin use, have never been reported. In our patient, transient cardiac arrhythmia or respiratory dysfunction related to cocaine and/or ethanol use were the most likely causes of cerebral hypoperfusion.

SNP sets selection under mutual information criterion, application to F7/FVII dataset

One of the main goals of human genetics is to find genetic markers related to complex diseases. In blood coagulation process, it is known that genetic variability in F7 gene is the most responsible for observed variations in FVII levels in blood. In this work, we propose a method for selecting sets of Single Nucleotide Polymorphisms (SNPs) significantly correlated with a phenotype (FVII levels). This method employs a feature selection algorithm (variant of Sequential Forward Selection, SFS) based on a criterion of statistical significance of a mutual information functional. This algorithm is applied to a sample of independent individuals from the GAIT project. Main SNPs found by the algorithm are in correspondence with previous results published using family-based techniques.

[Paraspinal arteriovenous malformations with perimedullary venous drainage]

Symptoms of chronic myelopathy in cases of paraspinal arteriovenous malformations are most often related to perimedullary venous drainage. Here, we report on three cases of such malformations that have unique epidural venous drainage. These thoracolumbar lesions manifested as isolated back pain (in two cases) and S1 lumboradicular pain (in one case). MRI presented evidence to suggest a diagnosis of these rare conditions, based on signs of vertebral erosion, signal loss (flow void) on T1- and T2-weighted imaging, and partial enhancement after gadolinium injection, with no signs of congestive myelopathy. Spinal angiography confirmed the presence of a paraspinal fistula and, at the same time, allowed treatment by intra-arterial onyx injection.

MRI-based score for acute basilar artery thrombosis

BACKGROUND

Intra-arterial thrombolysis may reduce mortality in acute basilar artery (BA) occlusion. We wanted to identify an easy-to-use pre-treatment MR-based predictor of clinical outcome in patients with acute BA occlusion treated with IAT.

METHODS

We analyzed 16 patients with acute BA occlusion prospectively. Vascular risk factors, as well as National Institutes of Health Stroke Scale (NIHSS) and Glasgow Coma Scale (GCS) scores were recorded on admission, together with a 10-point semiquantitative score reflecting the number of acute ischaemic brain lesions on diffusion-weighted imaging. The recanalization grade was evaluated by angiography. The clinical outcome, using the modified Rankin scale (mRs), was measured 3 months later.

RESULTS

Risk factors, NIHSS and GCS scores, time from symptom onset to treatment, recanalization rate, outcome and outcome predictors (such as age, NIHSS and GCS scores) were comparable to other studies. Haemorrhagic transformation of infarction occurred in 2 patients (12.5%). We found that a high lesion score was an additional predictor of poor outcome (p = 0.026).

CONCLUSIONS

In patients with acute BA occlusion, treated with intra-arterial recombinant tissue plasminogen activator, a high number of acute ischaemic lesions, based on diffusion-weighted imaging, is a predictor of poor clinical outcome.

[Diffusion-weighted MRI in sporadic Creutzfeldt-Jakob disease]

Conventional MRI with T1, T2 and FLAIR sequences has an important role for the diagnosis of Creutzfeldt-Jakob disease, but the usual examination does not exclude the disease. The objective of this study is to report on the role of diffusion-weighted imaging (DWI) in the diagnostic strategy. From 2002 to 2006, four patients with a suspected diagnosis of sporadic Creutzfeldt-Jakob disease, which was retrospectively confirmed, underwent DWI. In all patients, MRI demonstrated high-signal intensities on FLAIR sequences and on spin-echo T2-weighted MRI, with restricted diffusion of caudate and lenticular nuclei. In one patient, DWI revealed cortical high-signal intensities that were not visualized on either FLAIR or T2-weighted MRI. In two other patients, MRI showed restricted thalamic diffusion, which is a classic sign of the new variant of the disease. Thus, thalamic involvement can be found in the sporadic form of the disease. It can be revealed on DWI and by apparent diffusion coefficient (ADC) mapping or detected only by ADC measurement.