F. Tahon

Brain Stem Diffusion-Weighted Imaging Lesion Score: A Potential Marker of Outcome in Acute Basilar Artery Occlusion

BACKGROUND AND PURPOSE: The benefit of recanalization in basilar artery occlusion (BAO) has been established. The baseline extent of brain stem damage may also influence the outcome. We investigated whether a baseline diffusion-weighted imaging (DWI) score may provide additional prognostic value in BAO. MATERIALS AND METHODS: We analyzed baseline clinical and DWI parameters in consecutive patients treated with endovascular procedures for acute BAO. Brain stem DWI lesions were assessed by using a semiquantitative score based on arterial territory segmentation. Outcome at 3 months was dichotomized according to the modified Rankin Scale (mRS) as favorable (mRS, 0–2) or unfavorable (mRS, 3–6). Spearman rank correlation tests assessed the correlation between DWI and clinical variables. Univariate and multivariate logistic regression analyses were used to identify clinical and MR imaging predictors of outcome. RESULTS: Twenty-nine patients were included. The brain stem DWI score (median, 3; range, 0–14) was correlated with the baseline National Institutes of Health Stroke Scale (NIHSS) score and the presence and length of coma (r = 0.67, 0.49, and 0.53, respectively; P < .01). Recanalization was achieved in 76%. A higher baseline NIHSS score (P = .02) and brain stem DWI score (P = .03), a lower Glasgow Coma Scale score (P = .04), and the presence of coma (P = .05) were associated with poor outcome in univariate analysis. Multivariate analysis showed that the brain stem DWI score was the only independent baseline predictor for clinical outcome (P = .026). CONCLUSIONS: Baseline brain stem DWI lesion score is an independent marker of outcome in BAO.

Recovery of third nerve palsy after endovascular treatment of posterior communicating artery aneurysms

BACKGROUND High recovery rates after endovascular treatment of TNP-inducing PcomA aneurysms have been reported. However, only few and often small series were reported. The results of the 2 available comparative studies are controversial. Choosing clipping or coiling as treatment modality nowadays is still a matter of debate. We report the ophthalmologic outcome of 20 consecutive patients treated by coiling of TNP-inducing PcomA aneurysms. METHODS The third nerve function before and after endovascular treatment was assessed and studied retrospectively. Predictive recovery factors known from literature including treatment timing, the degree of preoperative nerve deficit, the association with SAH, coil type, cardiovascular risk factors, and age were analyzed. A review of the literature was performed. RESULTS Eight patients presented initially with complete nerve palsy (40%) and 12 with partial palsy (60%). Eleven patients had SAH. The mean aneurysm size was 7.14 mm; there were no partially thrombosed aneurysms. Of the 20 patients, 19 (95%) recovered. Recovery was complete in 7 patients (35%), partial in 12 patients (60%), and 1 patient remained unchanged (5%). The mean duration of follow-up was 24.7 months. One patient with complete TNP recovered completely after 5 months of coiling. One case of late complete nerve recovery was observed at 20 months. No cases of reoccurrences or worsening of the partial TNP were observed, including patients who developed recanalization of the aneurysmal sac. Clinical presentation with SAH and early management were statistically significant factors that positively influenced nerve recovery (P = .006549 and P = .015718, respectively). Initial partial TNP seems to influence recovery but did not reach significance (P = .079899). CONCLUSION Coiling of PcomA aneurysms is associated with high rates of third nerve function recovery. Complete recovery can be expected even after long periods and in cases of initial complete nerve palsy. The early treatment and the association with SAH seem to promote the nerve recovery.

Perfusion magnetic resonance imaging: Comparison of semiologic characteristics in first-pass perfusion of brain tumors at 1.5 and 3 Tesla

OBJECTIVES To investigate whether using 3 Tesla (T) instead of 1.5T modifies the data obtained from first-pass perfusion in relation to the quantitative values of cerebral blood volume (CBV) and estimation of micro-vascular leakage (MVL). To describe the differences in data in the setting of neuro-oncology cases and propose explanations based on the discrepancies. MATERIAL AND METHODS In total, 21 patients presenting an intracranial intra-axial space-occupying lesion underwent two MRI explorations, one at 1.5T and another at 3T, including a first-pass perfusion sequence using sequence parameters, defined by the manufacturer Philips. Using a gamma variate analysis, the ratio of cerebral blood volume (rCBV) in tumor, peritumoral, and normal appearing areas was first assessed. After a global analysis, a subgroup analysis was conducted according to the rCBV value measured at 1.5T. Lastly, MVL was assessed based on the signal intensity recorded above baseline after the passage of the contrast medium. RESULTS At 3T, compared to 1.5T data that are currently the reference, rCBV was constantly and significantly over-evaluated (P=0.0041 for all tumors), while MVL was constantly and significantly under-evaluated (P<0.0001 for all tumors). DISCUSSION The increase in magnetic field strength along with the associated modifications in sequence parameters led to variations in rCBV and MVL when measured using first-pass perfusion. In some cases, such as lymphomas, there was a loss of diagnostic information. It therefore appears necessary to optimize the acquisition parameters to allow for radiologic semiology to become relevant again.

Acute perfusion MR imaging in a HaNDL-like syndrome.

Case Report A 44-year-old right-handed man, with no history of migraine or cardiovascular risk factors, developed acute numbness and weakness involving the right leg and ascending to the right arm and the face, with aphasia and right homonymous hemianopsia. The symptoms cleared within 8 h. Cerebral MR imaging performed 2 h after the onset of symptoms – including T 2 diffusion-weighted fluid-attenuated inversion recovery (FLAIR) images, MR angiograms (time of flight: cerebral and cervical) and perfusion analysis (time to peak map, cerebral blood volume, cerebral blood flow) – revealed a global left-hemispherical hypoperfusion. The mean time-to-peak delay in the affected hemisphere versus the contralateral side was 2.5 s. The cerebral blood flow ratio was 0.71. There was no clinical or laboratory evidence of a systemic infection. CSF analysis revealed mononuclear pleocytosis (91% lymphocytes, 9% monocytes) with 340 cells/mm 3 , glucose level of 3 mmol/l and protein level of 2 g/l. Specific biological tests ruled out any infectious, immunological, metabolic or prothrombotic condition. An exhaustive neurovascular workup failed to detect any arterial or cardiac source of ischemic stroke. Hemodynamic abnormalities cleared on day 2 after MRI. Electroencephalography at day 2 showed a non-epileptiform focal slowing on the left hemisphere, which persisted for 1 week after onset. Two months later, the EEG was normal, whereas CSF showed lymphocytic pleocytosis (65 cells/mm 3 , 98% lymphocytes) and a raised protein level (0.54 g/l). He resumed his previous activities 2 weeks later. No recurrence was observed after a follow-up of 15 months.

Stenting of Symptomatic Basilar and Vertebral Artery Stenosis in Patients Resistant to Optimal Medical Prevention: The Lyon Stroke Unit Experience

Intracranial angioplasty stenting may be an efficient therapy in patients with intracranial atherosclerotic symptomatic vertebrobasilar artery stenosis unresponsive to optimal medical therapy. We present our experience in this setting. Results: The study included 12 cases (8 men, 4 women), with an age range of 43–78 years (mean 62.6 years). Intracranial stenosis that resulted in qualifying stroke or transient ischemic attack involved the vertebral artery (n = 4), lower basilar artery (n = 1) and mid basilar artery (n = 5). Tandem stenosis included the intracranial vertebral artery and basilar artery (n = 1) and both intracranial vertebral arteries (n = 1). The degree of stenosis ranged between 70 and 90% in the basilar and vertebral arteries. Angioplasty + stenting was performed in all lesions. A successful procedure resulting in 30% of residual stenosis was found in 14 vessels. A periprocedural adverse event occurred in 1 case and was related to a brain hemorrhage. The mean patient follow-up was 15 ± 3 months; 10 patients remained symptom free. All patients underwent a percutaneous endovascular balloon angioplasty and stent placement. Conclusions:This study supports the safety and the potential efficiency of stent-assisted angioplasty in patients resistant to optimal prevention. Randomized larger prospective trials are needed to confirm the benefit of this approach.

Stenting of a cerebral venous thrombosis

Cerebral venous and sinus thrombosis (CVT) is a rare but potentially alarming condition, which remains a diagnostic and therapeutic challenge. Endovascular procedure may be a therapeutic option when evolution is unfavourable despite medical treatment, but the use of stenting is rarely reported in CVT treatment. We report the case of a man who presented a jugular vein thrombosis responsible for severe intracranial hypertension. Because of clinical worsening despite intravenous heparin and symptomatic treatment, endovascular procedure including the placement of five venous stents, thrombolysis and balloon angioplasty, was performed and led to venous recanalization with successful clinical outcome. The patient is still asymptomatic 3 years later. Our report shows that venous stenting could represent an efficient alternative in the management of decoagulation refractory CVT.

Normalization of cerebral vasoreactivity using BOLD MRI after intravascular stenting

Background and purpose: Intravascular angioplasty and stenting of intracranial arterial stenosis provided controversial results. Besides the expertise of the practitioners, the selection of the patients remains challenging. BOLD MRI of the cerebral vasoreactivity (BOLD MRI CVR) to hypercapnia provides reproducible maps of the entire brain of the vascular reserve, and could be helpful to assess the best therapeutic strategy. Case history: We report the case of a 63‐year‐old woman referred for a severe stenosis of the proximal portion of the left middle cerebral artery, revealed by a lenticulostriate and precentral infarction. Despite an aggressive medical treatment during 5 months, the occurrence of iterative transient ischemic attacks motivated intravascular stenting. Functional MRI of the vasoreactivity to hypercapnia using both Blood Oxygen Level Dependent (BOLD) and arterial spin labeling sequences showed normal basal perfusion and impaired vasoreactivity in the left middle cerebral artery territory. Three months after stenting, the BOLD MRI CVR showed vasoreactivity normalization. Since, the patient remains free of ischemic disorders one year after stenting. Conclusion: BOLD MRI of the CVR to hypercapnia may be helpful to optimize the treatment of patients with intracranial arterial stenosis, and could be performed in future therapeutic trials. Hum Brain Mapp 35:1320–1324, 2014.

Cerebral imaging in infectious endocarditis: A clinical study

Abstract Background: Because neurological failure is the most frequent extra-cardiac complication in Infectious Endocarditis (IE), a brain computerised tomography (CT) scan is usually performed. The benefits of magnetic resonance imaging (MRI) have not been clearly established. This study aims to clarify the prevalence and type of cerebral lesions in IE detected using MRI and to compare them with those detected using CT scans. Methods: In the Grenoble University Hospital, patients diagnosed with definite or possible endocarditis according to Duke’s criteria were screened from 2010–2012. Brain CT and MRI were performed as soon as possible after diagnosis. Results: Of the 62 patients with IE who underwent at least one cerebral imaging within 3 weeks of diagnosis, Streptococcus (29) and Staphylococcus (14) were the main micro-organisms present. Twenty-eight (45%) patients underwent cardiac surgery. Eight (13%) died before discharge. Twenty (32%) had neurological symptoms. A brain CT-scan was performed on 53 (85%) patients and a MRI was performed on 43 (69%) patients. CT was pathological in 26 (49%) patients, whereas 32 (74%) MRI demonstrated abnormalities. The MRI lesions were classified as follows: ischaemia (48%), microbleeds (34%), haemorrhages (16%), abscesses (9%) and microbial aneurysms (4%). Of the 37 patients who underwent both MRI and CT examinations, ischaemia (48% vs 35%) and microbleeds (34%) demonstrated the difference between the two imaging methods. Conclusion: Through the early diagnosis of cerebral damage, even in asymptomatic cases, MRI may have a role in the IE management, influence any surgical decision and assist in prognosis assessment.

Greater occipital nerve MR tractography: Feasibility and anatomical considerations

BACKGROUND AND PURPOSE To assess the feasibility of greater occipital nerve (GON) tractography using a fully automated tractography technique on the whole-neck volume, in comparison with anatomical knowledge. METHODS Healthy subjects were consecutively included in this study if they had no history or symptoms of headache or brain disorder. A 3T MRI scanner with a 32 channel head coil was used. The following parameters for Diffusion Weighed (DWI) were used: b value of 1000 s/mm2, 32 directions, acquired voxel size: 2 mm isotropic. High-Order tractography with the Constrained Spherical Deconvolution (CSD) model was generated. Track-Weighted Imaging (TWI) maps were generated with MRTrix. Two radiologists performed blind evaluations of the GON pathways on TWI maps. RESULTS A total of 20 healthy subjects were included (12 males and eight females, mean age 53.8 years old). In comparison with anatomical atlas, GON complete visualization (from C1-C2 origin to muscular emergence) was possible in 18 out of 20 healthy subjects. In two cases, GON was not visible in the cervical spine foramen. CONCLUSION Tractography through TWI is a feasible technique to accurately depict GON. This technique may appear as a promising technique for therapeutic management of patients with occipital neuralgia.

Facet joint syndrome: from diagnosis to interventional management

Low back pain (LBP) is the most common pain syndrome, and is an enormous burden and cost generator for society. Lumbar facet joints (FJ) constitute a common source of pain, accounting for 15–45% of LBP. Facet joint degenerative osteoarthritis is the most frequent form of facet joint pain. History and physical examination may suggest but not confirm facet joint syndrome. Although imaging (radiographs, MRI, CT, SPECT) for back pain syndrome is very commonly performed, there are no effective correlations between clinical symptoms and degenerative spinal changes. Diagnostic positive facet joint block can indicate facet joints as the source of chronic spinal pain. These patients may benefit from specific interventions to eliminate facet joint pain such as neurolysis, by radiofrequency or cryoablation. The purpose of this review is to describe the anatomy, epidemiology, clinical presentation, and radiologic findings of facet joint syndrome. Specific interventional facet joint management will also be described in detail.Teaching points• Lumbar facet joints constitute a common source of pain accounting of 15–45%.• Facet arthrosis is the most frequent form of facet pathology.• There are no effective correlations between clinical symptoms, physical examination and degenerative spinal changes.• Diagnostic positive facet joint block can indicate facet joints as the source of pain.• After selection processing, patients may benefit from facet joint neurolysis, notably by radiofrequency or cryoablation.