Arteriovenous shunts and capillary blush as an early sign of basal ganglia infarction after successful mechanical intra-arterial thrombectomy in ischaemic stroke.

OBJECTIVES: Recent studies indicate an interest in early infarct assessment, mainly using post-interventional perfusion imaging. This work evaluated two specific angiographic signs for infarct prediction in the basal ganglia immediately after successful mechanical intra-arterial thrombectomy. METHODS: In this retrospective study, 57 consecutive patients (mean ± SD age 67 ± 15 years) with acute occlusion of the proximal anterior circulation who underwent mechanical thrombectomy of the M1 segment of the middle cerebral artery were included. Two separate angiographic signs, early venous drainage and capillary blush, were identified and analysed regarding their statistical significance for infarct prediction within the basal ganglia. RESULTS: Four patients were excluded due to parenchymal haemorrhage. Forty-four of 53 patients developed infarction of the basal ganglia. Sensitivity/specificity were 93%/27%, respectively, for the capillary blush sign and 88%/63%, respectively, for the early venous drainage sign. Combining both signs increased the sensitivity and specificity to 88% and 81%, respectively, and increased the positive predictive value to 95%. CONCLUSIONS: Both angiographic signs seem to predict the irreversible damage of tissue in the basal ganglia reliably despite successful recanalization of the middle cerebral artery in patients with ischaemic stroke. KEY POINTS: • Evaluation of success in neurointerventional procedures is mainly based on recanalization rates. • Two separate angiographic signs can predict infarction immediately after proximal MCA recanalization. • Combining both signs increases their specificity.

Quantification of Internal Carotid Artery Stenosis with 3D Ultrasound Angiography.

PURPOSE: The aim of this study was to evaluate a new method of three-dimensional ultrasound (3D-US) angiography of carotid vessels including 3D-US quantification of internal carotid artery (ICA) stenosis (ICAS). MATERIALS AND METHODS: Two neurologists performed native ultrasound scans of the brain-supplying carotid arteries in 73 probands (including 22 patients with 25 cases of ICAS) using a Toshiba Aplio 500 ultrasound machine equipped with the 3 D application of Curefab CS. Additionally, 25 probands underwent contrast-enhanced magnetic resonance angiography (CE-MRA) of the neck vessels. RESULTS: The mean length of the proximal ICA was 32.1 mm ±â€Š9.8 mm & 31.3 mm ±â€Š9.0 mm (each n = 97). The interrater reliability (intraclass correlation, ICC) was 0.75 ±â€Š0.23 for the common carotid artery (CCA, n = 90) and 0.78 ±â€Š0.21 (n = 92) for the ICA. The intermethod agreement between 3D-US angiography and CE-MRA was 0.67 ±â€Š0.19 (n = 45) & 0.66 ±â€Š0.19 (n = 44) for the CCA and 0.79 ±â€Š0.17 (n = 47) & 0.75 ±â€Š0.19 (n = 46) for the ICA. Quantification of ICAS applying 3D-US in comparison to 2D color-coded duplexsonography (2D-CDS) showed a moderate to good intermethod agreement both by the Bland and Altman analysis and by ICC (0.8 & 0.72; with each p < 0.001). The interrater reliability for quantification of ICAS was 0.79; p < 0.001. CONCLUSION: Native 3D-US angiography of carotid vessels shows good interrater and intermethod agreement in comparison to CE-MRA. Together with a moderate to good intermethod and interrater agreement in the quantification of ICAS, when compared to 2D-CDS, 3D-US angiography is thus a promising complementary imaging technique for carotid artery disease.

High Resolution Imaging of Viscoelastic Properties of Intracranial Tumours by Multi-Frequency Magnetic Resonance Elastography.

PURPOSE: In recent years Magnetic Resonance Elastography (MRE) emerged into a clinically applicable imaging technique. It has been shown that MRE is capable of measuring global changes of the viscoelastic properties of cerebral tissue. The purpose of our study was to evaluate a spatially resolved three-dimensional multi-frequent MRE (3DMMRE) for assessment of the viscoelastic properties of intracranial tumours. METHODS: A total of 27 patients (63 ± 13 years) were included. All examinations were performed on a 3.0 T scanner, using a modified phase-contrast echo planar imaging sequence. We used 7 vibration frequencies in the low acoustic range with a temporal resolution of 8 dynamics per wave cycle. Post-processing included multi-frequency dual elasto-visco (MDEV) inversion to generate high-resolution maps of the magnitude |G*| and the phase angle φ of the complex valued shear modulus. RESULTS: The tumour entities included in this study were: glioblastoma (n = 11), anaplastic astrocytoma (n = 3), meningioma (n = 7), cerebral metastasis (n = 5) and intracerebral abscess formation (n = 1). Primary brain tumours and cerebral metastases were not distinguishable in terms of |G*| and φ. Glioblastoma presented the largest range of |G*| values and a trend was delineable that glioblastoma were slightly softer than WHO grade III tumours. In terms of φ, meningiomas were clearly distinguishable from all other entities. CONCLUSIONS: In this pilot study, while analysing the viscoelastic constants of various intracranial tumour entities with an improved spatial resolution, it was possible to characterize intracranial tumours by their mechanical properties. We were able to clearly delineate meningiomas from intraaxial tumours, while for the latter group an overlap remains in viscoelastic terms.

[Deep brain stimulation using simultaneous stereotactic electrode placement: an alternative to conventional functional stereotaxy?]. / Tiefe Hirnstimulation mittels simultaner stereotaktischer Elektrodenplatzierung : Eine Alternative zur konventionellen funktionellen Stereotaxie?

BACKGROUND: Deep brain stimulation (DBS) has become a reliable method in the treatment of movement disorders, e.g. idiopathic Parkinson's disease (IPD) and is technically based on stereotaxy. The Starfix® platform is a new type of stereotactic frame that allows an individualized and patient-optimized therapeutic regimen in IPD. OBJECTIVES: The aim of this study was to retrospectively compare the outcomes of IPD patients who underwent surgery with the use of conventional stereotactic frames (31 patients) to those who underwent implantation of DBS with the use of Starfix® frames (29 patients). MATERIAL AND METHODS: Surgery time, the unified Parkinson's disease rating scale III (UPDRS/III) score, L-dopa and L-dopa equivalent doses (LED) were compared prior to surgery as well as 4 weeks, 12 weeks, 6 months and 1 year postoperatively. RESULTS: The IPD-related symptoms improved significantly in both groups with respect to the UPDRS III score (conventional 69.6% vs. 72.4% Starfix®). After surgery significant reductions of L-dopa and LED were seen in both groups. Inherent advantages of the Starfix® platform included simultaneous positioning of the stimulating electrodes and a significant reduction in surgical time. CONCLUSION: In summary, both stereotactic procedures are reliable and safe procedures for the placement of stimulating electrodes as well as the stimulation effect achieved. The logistical uncoupling of presurgical planning from surgical therapy emphasizes the benefits of the individualized stereotactic procedure.

Predicting intracerebral hemorrhage by baseline magnetic resonance imaging in stroke patients undergoing systemic thrombolysis.

OBJECTIVES: Intracerebral hemorrhage (ICH) remains a serious complication in ischemic stroke patients undergoing systemic thrombolysis. Here, we examined whether the risk of treatment-associated hemorrhage can be predicted from magnetic resonance imaging (MRI) using fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted imaging (DWI) within 3 h after symptom onset. METHODS: In this single-center observational study involving 122 ischemic stroke patients between January 2005 and December 2008, the incidence of FLAIR-positive lesions within diffusion-restricted areas was determined on baseline MRI, which was carried out prior to treatment with tissue plasminogen activator (Actilyse(®) ) within 3 h from symptom onset. The rate of ICH was assessed by computed tomography performed within 24 h after treatment. Relationships between FLAIR-positive lesions, DWI lesion size, proportion of FLAIR/DWI-positive lesions, and occurrence of bleeding were explored. RESULTS: Data from 97 patients were evaluated. FLAIR-positive lesions were present in 25 patients (25.8%) and ICH occurred in 32 patients (33.0%). FLAIR-positive lesions were associated with a bleeding rate of 80.0% compared with 16.7% in FLAIR-negative patients (P < 0.001; odds ratio 20.0, positive predictive value 0.8). DWI lesion size was significantly correlated with the rate of ICH (P = 0.001). In contrast, FLAIR/DWI proportion was not associated with ICH (P = 0.788). CONCLUSIONS: In ischemic stroke patients within 3 h from symptom onset, the existence of FLAIR-positive lesions on pretreatment MRI is significantly associated with an increased bleeding risk due to systemic thrombolysis. Therefore, considering FLAIR-positive lesions on baseline MRI might guide treatment decisions in ischemic stroke.

[Use of a newly developed piezoelectrically driven drilling machine for MR-guided bone biopsies]. / Einsatz einer neu entwickelten Bohrmaschine mit piezoelektrischem Antrieb für die Durchführung von Knochenbiopsien im offenen MRT.

PURPOSE: Development and clinical testing of an MR-compatible bone biopsy system, to enable the sample collection from osteosclerotic or subcortical lesions for histological investigation under MR control. MATERIALS AND METHODS: A piezoelectrically driven drilling machine was constructed and tested in connection with an MR-compatible bone biopsy set in a vertical open MR scanner (0.5 T) on a phantom and 10 patients with ambiguous bone lesions. Images were obtained using T(1)-weighted spin-echo sequences and, in case of real-time imaging, a fast spoiled gradient-echo sequence. RESULTS: The influence of the enabled motor (RF-interference) leads to a reduction of the signal to noise ratio of the images, but can be minimised by appropriate measures. The observed slight field distorsions do not affect the image quality during real time acquisition in a substantial manner. No complications occurred. The extracted biopsy material was sufficient and of good quality. CONCLUSIONS: In spite of slightly restricted image quality, the described drilling machine combined with the bone biopsy set is well suited for MR-guided bone biopsies, which require the application of a motor driven drill. Its application within an interventional MR scanner is safe and its handling simple and manageable.