Basal Ganglia versus Peripheral Infarcts: Predictive Value of Early Fiber Alterations.

BACKGROUND AND PURPOSE: Impairment of fiber integrity of the corticospinal tract in the subacute and chronic phases after ischemic stroke has been linked to poor motor outcome. The aim of the study was an assessment of fiber integrity in the acute poststroke phase and an evaluation of its association with the clinical course dependent on the infarction pattern (subtypes: peripheral versus basal ganglia infarction). MATERIALS AND METHODS: All patients who underwent mechanical recanalization of a large-vessel occlusion in the anterior circulation and postinterventional DTI were included (n = 165). The fractional anisotropy index of the patient-specific corticospinal tract within the posterior limb of the internal capsule was correlated to clinical parameters (NIHSS scores/mRS at 90 days), and the interaction of stroke subtype (peripheral infarcts versus basal ganglia infarction) was tested in a moderation analysis. RESULTS: The fractional anisotropy index was reduced in the acute poststroke phase with a correlation to clinical presentation, especially in case of peripheral infarcts (eg, with the NIHSS motor subscore: r = -0.4, P < .001). This correlation was absent for basal ganglia infarction (r = -0.008, P > .05). There was a significant association between the fractional anisotropy index and clinical outcome (mRS after 90 days, P < .01), which is moderated by stroke subtype with significant effects only for peripheral infarcts. CONCLUSIONS: Corticospinal tract abnormalities can be observed in the early stage after mechanical recanalization and have prognostic capacity. This finding increases the clinical value of early DTI imaging parameters. Because the effects observed were limited to peripheral infarcts, further and longitudinal evaluation of fiber integrities within basal ganglia infarction is required.

A short history of thrombectomy - Procedure and success analysis of different endovascular stroke treatment techniques.

BACKGROUND: The historical development of interventional stroke treatment shows a wide variation of different techniques and materials used. Thus, the question of the present work is whether the technical and procedural differences of thrombectomy techniques lead to different technical and clinical results. METHODS AND RESULTS: Analysis of a mixed retrospective/prospective database of all endovascular treated patients with an occlusion of the Carotid-T or M1 segment of the MCA at a single comprehensive stroke center since 2008. Patients were classified regarding the technical approach used. Six hundred sixty-eight patients were available for the final analysis. Reperfusion rates ranged between 56% and 100% depending on the technical approach. The use of balloon guide catheters and most recently the establishment of combination techniques using balloon guide catheters, aspiration catheters and stent retrievers have shown a further significant increase in the rates of successful recanalization, full recanalization and first-pass recanalization. Additionally, the technical development of interventional techniques has led to a subsequent drop in complications, embolization into previously unaffected territories in particular. CONCLUSION: Technical success of MT has improved substantially over the past decade owing to improved materials and procedural innovations. Combination techniques including flow modulation have emerged to be the most effective approach and should be considered as a standard of care.Level of evidence: Level 3, retrospective study.

Thrombus Histology of Basilar Artery Occlusions : Are There Differences to the Anterior Circulation?

BACKGROUND: For patients with acute vessel occlusions of the anterior circulation histopathology of retrieved cerebral thrombi has been reported to be associated to stroke etiology. Due to the relatively small incidence of posterior circulation stroke, exclusive histopathologic analyses are missing for this subgroup. The aim of the study was to investigate thrombus histology for patients with basilar artery occlusions and uncover differences to anterior circulation clots with respect to underlying etiology. METHODS: A total of 59 basilar thrombi were collected during intracranial mechanical recanalization and quantitatively analyzed in terms of their relative fractions of the main constituents, e.g. fibrin/platelets (F/P), red (RBC) and white blood cells (WBC). Data were compared to histopathological analyses of 122 thrombi of the anterior circulation with respect to underlying pathogenesis. RESULTS: The composition of basilar thrombi differed significantly to thrombi of the anterior circulation with an overall higher RBC amount (median fraction in % (interquartile range):0.48 (0.37-0.69) vs. 0.37 (0.28-0.50), p < 0.001) and lower F/P count (0.45 (0.21-0.58) vs. 0.57 (0.44-0.66), p < 0.001). Basilar thrombi composition did not differ between the different etiological stroke subgroups. CONCLUSION: The results depict a differing thrombus composition of basilar thrombi in comparison to anterior circulation clots with an overall higher amount of RBC. This may reflect different pathophysiologic processes between anterior and posterior circulation thrombogenesis, e.g. a larger proportion of appositional thrombus growth in the posterior circulation.

Etiology of recurrent large vessel occlusions treated with repeated thrombectomy.

BACKGROUND: Repeated mechanical thrombectomy for acute stroke treatment in individual patients has been proven feasible. However, less is known about the etiology of recurrent vessel occlusions after prior thrombectomy. We aimed to understand if the etiology of such recurrent events differs from the first stroke. METHODS: Retrospectively, we identified all patients at our center who received a repeated mechanical thrombectomy between 2007 and 2019. Clinical data were retrieved from medical records. Etiology of stroke was evaluated retrospectively, and angiographic studies were revisited. RESULTS: Twenty-three patients (1.5%) were identified. Median age was 68 years (IQR 56-77). Median NIHSS at first admission was 11 points (IQR 5-15). In nine cases (39.1%), the recurrent vessel occlusion was located exactly at the same position as the prior occlusion. Overall, five (21.7%) patients had a remarkable extracranial pathology as likely cause of stroke recurrence. In 16 patients (69.6%), the etiology of the first stroke and its recurrence was considered as likely being the same, mostly of cardioembolic or unknown origin. In the seven remaining patients (30.4%), the cause of stroke possibly differed from the first event, with five patients (21.7%) having a postinterventional intracranial intimal lesion as possible cause of stroke. CONCLUSION: Incidence of repeated thrombectomy was low. However, the high number of patients with known origin of stroke etiology raises the question how their monitoring may be optimized. The number of patients with remarkable extracranial pathologies or intracranial endothelial lesions supports current clinical practice to pay attention to final angiographic series.

Microstructural Integrity of Salvaged Penumbra after Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: There are sparse data on the microstructural integrity of salvaged penumbral tissue after mechanical thrombectomy of large-vessel occlusions. The aim of the study was to analyze possible microstructural alteration in the penumbra and their association with clinical symptoms as well as angiographic reperfusion success in patients undergoing mechanical thrombectomy. MATERIALS AND METHODS: All patients who underwent mechanical thrombectomy for large-vessel occlusions in the anterior circulation and who received an admission CT perfusion together with postinterventional DTIs were included (n = 65). Angiographic reperfusion success by means of modified Thrombolysis in Cerebral Infarction (mTICI) scale and clinical outcome were recorded. Microstructural integrity was assessed by DTI evaluating the mean diffusivity index within the salvaged gray matter of the former penumbra. RESULTS: The mean diffusivity index was higher in completely recanalized patients (mTICI 3: -0.001 ± 0.034 versus mTICI <3: -0.030 ± 0.055, P = .03). There was a positive correlation between the mean diffusivity index and NIHSS score improvement (r = 0.49, P = .003) and the mean diffusivity index was associated with midterm functional outcome (r = -0.37, P = .04) after adjustment for confounders. In mediation analysis, the mean diffusivity index and infarction growth mediated the association between reperfusion success and clinical outcomes. CONCLUSIONS: The macroscopic salvaged penumbra included areas of microstructural integrity changes, most likely related to the initial hypoperfusion. These abnormalities were found early after mechanical thrombectomy, were dependent on angiographic results, and correlated with the clinical outcome. When confirmed, these findings prompt the evaluation of therapies for protection of the penumbral tissue integrity.

Aspiration thrombectomy in clinical routine interventional stroke treatment : Is this the end of the stent retriever era?

PURPOSE: The aim of our study was the technical evaluation of a first pass approach of primary thrombus aspiration (AST) in patients with emergency large intracerebral vessel occlusions (ELVO) under routine clinical conditions. MATERIALS AND METHODS: We collected procedural and clinical data of 104 patients who underwent mechanical thrombectomy due to ELVO between June 2014 and January 2016 with intentional first-line thrombus aspiration. Procedures were conducted due to occlusions of the distal internal carotid artery, middle cerebral artery, anterior cerebral artery, basilar artery and posterior cerebral artery and were performed with the patient under either conscious sedation or general anesthesia. If the AST technique failed completely or to some extent, stent retriever-based thrombectomy (SRT) was performed. RESULTS: As a stand-alone method AST was successful in achieving TICI (Thrombolysis in Cerebral Infarction) score 2b or 3 results in 29 cases (27.8%). After additional use of SRT successful recanalization was achieved in a total of 95 cases (91.3%, p = 0.048). If AST was performed exclusively, median procedure time until TICI 2b/3 was 15 min, in cases of combined procedures 35 min (p = 0.001). Subarachnoid hemorrhage (SAH) after thrombectomy appeared only if additional SRT was performed (12.0%) and not in cases of AST maneuvers alone (p = 0.09). CONCLUSION: When used as a first pass attempt AST is a fast and safe approach for patients suffering from stroke due to ELVO. Nonetheless, early conversion to SRT is needed in most cases and leads to overall excellent procedural results with low complication rates.

Risk of Thrombus Fragmentation during Endovascular Stroke Treatment.

BACKGROUND AND PURPOSE: Periprocedural thrombus fragmentation is a relevant risk in endovascular stroke treatment. Because factors influencing its occurrence are largely unknown, this study addresses a potential relationship between thrombus histology and clot stability. MATERIALS AND METHODS: Eighty-five patients with anterior circulation stroke treated with thrombectomy were included in this retrospective study. The number and location of emboli after retrieving the primary thrombus, the number of maneuvers, and TICI scores were evaluated. H&E and neutrophil elastase staining of retrieved clots was performed, and semiquantitative measurements of thrombus components were correlated with procedural parameters. RESULTS: An inverse correlation between maneuvers required for thrombus retrieval and the number of distal and intermediate emboli was observed (Spearman r, -0.23; P = .032). Younger patients were at higher risk for periprocedural thrombus fragmentation (Spearman r, -0.23; P = .032). Bridging thrombolysis tended to be associated with fewer maneuvers (2 vs 3, P = .054) but more emboli (1 vs 0, P = .067). While no consistent correlation between procedural parameters and red/white blood cells and fibrin-/platelet fractions could be found, higher amounts of neutrophil elastase-positive cells within the thrombus were independently associated with the occurrence of multiple emboli (adjusted OR, 4.6; 95% CI, 1.1-19.7; P = .041) and lower rates of complete recanalization (adjusted OR, 0.3; 95% CI, 0.1-0.9; P = .050). CONCLUSIONS: Younger age, easy-to-retrieve thrombi, and bridging thrombolysis may be risk factors for periprocedural thrombus fragmentation. Findings from standard histologic stains did not provide insight into thrombectomy-relevant thrombus stability. However, higher neutrophil levels in the thrombus tissue were related to an increased risk of periprocedural thrombus fragmentation. This observation aligns with the proposed thrombolytic capacity of neutrophil elastase and points to its potential clinical relevance in the context of stroke thrombectomy.

Reliability of Semi-Automated Segmentations in Glioblastoma.

PURPOSE: In glioblastoma, quantitative volumetric measurements of contrast-enhancing or fluid-attenuated inversion recovery (FLAIR) hyperintense tumor compartments are needed for an objective assessment of therapy response. The aim of this study was to evaluate the reliability of a semi-automated, region-growing segmentation tool for determining tumor volume in patients with glioblastoma among different users of the software. METHODS: A total of 320 segmentations of tumor-associated FLAIR changes and contrast-enhancing tumor tissue were performed by different raters (neuroradiologists, medical students, and volunteers). All patients underwent high-resolution magnetic resonance imaging including a 3D-FLAIR and a 3D-MPRage sequence. Segmentations were done using a semi-automated, region-growing segmentation tool. Intra- and inter-rater-reliability were addressed by intra-class-correlation (ICC). Root-mean-square error (RMSE) was used to determine the precision error. Dice score was calculated to measure the overlap between segmentations. RESULTS: Semi-automated segmentation showed a high ICC (> 0.985) for all groups indicating an excellent intra- and inter-rater-reliability. Significant smaller precision errors and higher Dice scores were observed for FLAIR segmentations compared with segmentations of contrast-enhancement. Single rater segmentations showed the lowest RMSE for FLAIR of 3.3 % (MPRage: 8.2 %). Both, single raters and neuroradiologists had the lowest precision error for longitudinal evaluation of FLAIR changes. CONCLUSIONS: Semi-automated volumetry of glioblastoma was reliably performed by all groups of raters, even without neuroradiologic expertise. Interestingly, segmentations of tumor-associated FLAIR changes were more reliable than segmentations of contrast enhancement. In longitudinal evaluations, an experienced rater can detect progressive FLAIR changes of less than 15 % reliably in a quantitative way which could help to detect progressive disease earlier.

Discrimination of Different Brain Metastases and Primary CNS Lymphomas Using Morphologic Criteria and Diffusion Tensor Imaging.

Purpose: Brain metastases are a common complication of cancer and occur in about 15 - 40 % of patients with malignancies. The aim of this retrospective study was to differentiate between metastases from different primary tumors/CNS lymphyomas using morphologic criteria, fractional anisotropy (FA) and apparent diffusion coefficient (ADC). Materials and Methods: Morphologic criteria such as hemorrhage, cysts, pattern of contrast enhancement and location were reported in 200 consecutive patients with brain metastases/primary CNS lymphomas. FA and ADC values were measured in regions of interest (ROIs) placed in the contrast-enhancing tumor part, the necrosis and the non-enhancing peritumoral region (NEPTR). Differences between histopathological subtypes of metastases were analyzed using non-parametric tests, decision trees and hierarchical clustering analysis. Results: Significant differences were found in morphologic criteria such as hemorrhage or pattern of contrast enhancement. In diffusion measurements, significant differences between the different tumor entities were only found in ADC analyzed in the contrast-enhancing tumor part. Among single tumor entities, primary CNS lymphomas showed significantly lower median ADC values in the contrast-enhancing tumor part (ADClymphoma 0.92 [0.83 - 1.07] vs. ADCno_lymphoma 1.35 [1.10 - 1.64] P = 0.001). Further differentiation between types of metastases was not possible using FA and ADC. Conclusion: There were morphologic differences among the main subtypes of brain metastases/CNS lymphomas. However, due to a high variability of common types of metastases and low specificity, prospective differentiation remained challenging. DTI including FA and ADC was not a reliable tool for differentiation between different histopathological subtypes of brain metastases except for CNS lymphomas showing lower ADC values. Biopsy, surgery and staging remain essential for diagnosis. Key Points: • Histopathological subtypes of brain metastases/CNS lymphomas show different morphologic features on MRI• Primary CNS lymphomas show significantly reduced ADC values• DTI is not a reliable tool for differentiation between brain metastases Citation Format: • Bette S, Wiestler B, Delbridge C et al. Discrimination of Different Brain Metastases and Primary CNS Lymphomas Using Morphologic Criteria and Diffusion Tensor Imaging. Fortschr Röntgenstr 2016; 188: 1134 - 1143.

The Impact of Histological Clot Composition in Embolic Stroke.

PURPOSE: Thrombus composition has been suggested to have a decisive impact on the outcome of patients treated by mechanical thrombectomy because of embolic stroke. The recent development of stent retrievers allows collection and, hence, histopathological analysis of fresh thrombus material. Against this background, the aim of this prospective study was to assess the impact of thrombus composition on mechanical recanalization, clinical outcome and stroke etiology. METHODS: Thirty-four patients suffering from acute ischemic stroke due to occlusion of the distal internal carotid artery/carotid-T, anterior cerebral artery, or middle cerebral arteries were mechanically recanalized, and thrombus material was obtained. Histological thrombus composition was compared with imaging, clinical, and neurointerventional data. RESULTS: The main findings were that a higher percentage of white blood cells (WBCs) in the thrombus was associated with (i) cardioembolic etiology, (ii) extended mechanical recanalization time, and (iii) less favorable recanalization (Thrombolysis in Cerebral Infarction score) and clinical outcome (National Institute of Health Stroke Scale). CONCLUSION: Our results suggest that thrombi with a high WBC fraction are related to more organized thrombi of cardioembolic origin associated with less favorable recanalization and clinical outcome in acute ischemic anterior circulation stroke. WBC-mediated immunological and coagulatory processes may play a key role in thrombus formation and pathogenesis of stroke warranting further investigation.

Susceptibility-weighted angiography (SWAN) of cerebral veins and arteries compared to TOF-MRA.

PROBLEM: High resolution, non-contrast imaging of both cerebral veins and arteries by use of gradient echo T2 star weighted angiography (SWAN) is a new method for susceptibility-weighted imaging with short acquisition times. We assessed the potential of this sequence for the depiction of both cerebral veins and arteries. METHODS: 15 healthy volunteers were included in the study. MRI was performed on a 3T MR scanner using the following sequences: (1) a 3D multi-echo gradient echo T2 star weighted angiography (SWAN), (2) an arterial 3D TOF MR angiography and (3) a venous 2D TOF. With regard to the SWAN sequence, both MinIP and MIP images were reconstructed and systematically compared to MIP reconstructions of the artTOF and the venTOF. To suggest possible clinical implications of our findings, we additionally included two illustrative cases. RESULTS: With regard to the visualization of the cerebral veins, the MinIP reconstructions of the SWAN sequence were considerably superior compared to the venTOF. Concerning the depiction of the main segments of the big cerebral arteries the value of the MIP reconstructions of the SWAN was comparable to that of the artTOF with limitations in the homogenity and in the depiction of smaller arteries. CONCLUSIONS: SWAN allows for high-resolution visualization of both cerebral veins and arteries in one sequence without application of contrast agent and with significantly shortened scan time compared to the combined scan time of TOF-MRA and TOF-MRV. By use of either MinIP or MIP reconstructions, the arteries can be distinguished from the veins.

[Improved localization of spinal AV fistulas using contrast-enhanced MR angiography at 3 T]. / Verbesserte Lokalisationsdiagnostik der spinalen duralen AV-Fistel durch die CE-MRA bei 3 T.

PURPOSE: The standard for the detection and localization of spinal dural and perimedullary AV fistulas has been digital subtraction angiography. The purpose of this study was to correctly locate dural AV fistulas using high-resolution (hr), contrast-enhanced (ce) MRA at 3 T or at least to estimate the site within a range of two to three segments. As a result, the radiation exposure, contrast dose and risk of complications were able to be reduced. METHODS: Five patients with typical clinical symptoms and the characteristic signs in spinal MRI were examined at 3 T (GE Signa Excite HD). Hr, ce MR angiography and a time-resolved sequence (TRICKS) were compared and correlated with the subsequent DSA and the operation record with respect to the site of the fistula. In addition, the amount of contrast agent and the number of selectively catheterized segmental arteries in DSA were analyzed. RESULTS: In all patients, a dural AV fistula was able to be demonstrated by hr, ce MRA, and the side and the segmental level of the point of the fistula were correctly predicted and confirmed in subsequent DSA as well as in the operation record. In time-resolved MRA the determined location was correct in one of the five cases. In the remaining 4 cases no definitive mapping was possible. CONCLUSION: In hr, ce MRA at 3 T the localization of the point of the fistula in a spinal AVF is highly reliable so that the radiation time and the amount of contrast medium can be reduced. Hr, ce MRA is superior to the time-resolved sequence (TRICKS).

[Stent-assisted angioplasty for atherosclerotic stenosis of the carotid artery. An overview]. / Stentgeschützte Angioplastie der arteriosklerotischen Stenose der A. carotis interna. Ein Uberblick.

For symptomatic stenosis of the carotid artery the invasive options for treatment (by means of stent or operation) are superior to conservative medical treatment. Recent multi-center randomized controlled trials, which will be presented here, indicate that stenting in the treatment of symptomatic carotid stenosis is neither safer nor more effective than carotid endarterectomy. When carried out by an experienced interventionalist stent-assisted angioplasty (CAS) is an alternative to carotid endarterectomy. Subgroup-analysis indicates that for patients older than 70 years of age invasive techniques should be the method of choice. In the case of contralateral high-grade stenosis or occlusion, CAS is the method of choice. For patients treated by stenting, the periprocedural complication rate is not influenced by the use of protection systems. The present results on symptomatic carotid stenosis should not be transferred to the therapy of asymptomatic carotid stenosis. A 3-armed study (SPACE2) on the comparison of the best medical treatment with the invasive treatment modalities (CAS or CEA) is in preparation and will be started in 2 months.

Lack of evidence of foetal microchimerism in female Spanish patients with systemic sclerosis.

Our objective was to study the presence of microchimerism in a series of 47 female Spanish patients with scleroderma (SSc) and to compare with a control group. Polymerase chain reaction was used to identify Y-chromosome sequences in DNA extracted from peripheral blood cells. Y-chromosome sequences were found in DNA from peripheral blood cells in four out of 47 (8.5%) patients with scleroderma (two limited and two diffuse) and in two out of 40 (5%) healthy women (no statistical differences were found). When we compared SSc patients and healthy controls who had had at least one male child, four out of 29 (13.7%) and two out of 26 (7.6%) had microchimerism respectively (no statistically significant differences were found). Patients with both scleroderma and persistent microchimerism had had a male offspring. Foetal microchimerism does not seem to play a major role in most cases of female Spanish patients with SSc.

[Primary Sjögren's syndrome: clinical and immunological characteristics of 114 patients]. / Síndrome de Sjögren primario: características clínicas e inmunológicas de 114 pacientes.

BACKGROUND: To analyze the clinical and immunological characteristics of a series of 114 patients with primary Sjögren's syndrome (PSS), and to evaluate the different diagnostic criteria and the association to lymphoproliferative disorders. PATIENTS AND METHOD: We included 114 patients (108 female and 6 male) with a diagnosis of PSS. All patients fulfilled the 1993 European Community criteria for the diagnosis of PSS and 76 patients fulfilled the San Diego Criteria. RESULTS: Mean age was 51 years with a mean follow-up of 7.3 years. The commonest clinical manifestation at onset (70%) was xerostomia/xerophtalmia (sicca syndrome). Extra glandular involvement was articular in 42% of cases, neurologic (35%), respiratory (21%) and hepatic (13%). Eleven patients (9%) developed vasculitis, and three (2%) developed a lympho-proliferative disorder. No statistically significant differences regarding symptoms at onset, frequency of glandular or extra glandular manifestations and severity of disease were observed between the two diagnostic criteria groups. HCV infection was associated with vasculitis (p < 0.001; OR: 20.6; CI 95%, 3.2-129) and lymphoproliferative disorders (p < 0.001). CONCLUSIONS: The clinical evolution of PSS does not vary when using different diagnostic criteria (San Diego and European Community criteria). A subset of patients with vasculitis and lymphoproliferative diseases is found to have an associated HCV infection.