TCCD Fusion Imaging to Estimate Intracranial Pressure and Tissue Displacement with Large Hemispheric Infarction.

BACKGROUND: Despite breakthroughs in stroke treatment, some patients still experience large infarctions of the cerebral hemispheres resulting in mass effect and tissue displacement. The evolution of mass effect is currently monitored using serial computed tomography (CT) imaging. However, there are patients who are ineligible for transport, and there are limited options for bedside monitoring of unilateral tissue shift. METHODS: We used fusion imaging for overlaying transcranial color duplex with CT angiography. This method allows overlay of live ultrasound on top of CT or magnetic resonance imaging scans. Patients with large hemispheric infarctions were eligible to participate. Position data from the source files were used and matched with live imaging and correlation to magnetic probes on the patient's forehead and ultrasound probe. Shift of cerebral parenchyma, displacement of the anterior cerebral arteries, basilary artery and third ventricle were analyzed, as well as pressure on the midbrain, and the displacement of the basilar artery on the head were analyzed. Patients received multiple examinations in addition to standard care of treatment with CT imaging. RESULTS: The sensitivity for diagnosing a shift of 3 mm with fusion imaging was 100%, with a specificity of 95%. No side effects or interactions with critical care equipment were recorded. CONCLUSIONS: Fusion imaging is an easy method to access and acquire measurements for critical care patients and follow-up of tissue and vascular displacement after stroke. Fusion imaging may be a decisive support for indicating hemicraniectomy.

Antiplatelet Therapy in Primary Spontaneous and Oral Anticoagulation-Associated Intracerebral Hemorrhage.

Background and Purpose- This study determined the influence of concomitant antiplatelet therapy (APT) on hematoma characteristics and outcome in primary spontaneous intracerebral hemorrhage (ICH), vitamin K antagonist (VKA)- and non-VKA oral anticoagulant-associated ICH. Methods- Data of retrospective cohort studies and a prospective single-center study were pooled. Functional outcome, mortality, and radiological characteristics were defined as primary and secondary outcomes. Propensity score matching and logistic regression analyses were performed to determine the association between single or dual APT and hematoma volume. Results- A total of 3580 patients with ICH were screened, of whom 3545 with information on APT were analyzed. Three hundred forty-six (32.4%) patients in primary spontaneous ICH, 260 (11.4%) in VKA-ICH, and 30 (16.0%) in non-VKA oral anticoagulant-associated ICH were on APT, and these patients had more severe comorbidities. After propensity score matching VKA-ICH patients on APT presented with less favorable functional outcome (modified Rankin Scale score, 0-3; APT, 48/202 [23.8%] versus no APT, 187/587 [31.9%]; P=0.030) and higher mortality (APT, 103/202 [51.0%] versus no APT, 237/587 [40.4%]; P=0.009), whereas no significant differences were present in primary spontaneous ICH and non-VKA oral anticoagulant-associated ICH. In VKA-ICH, hematoma volume was significantly larger in patients with APT (21.9 [7.4-61.4] versus 15.7 [5.7-44.5] mL; P=0.005). Multivariable regression analysis revealed an association of APT and larger ICH volumes (odds ratio, 1.80 [1.20-2.70]; P=0.005), which was more pronounced in dual APT and supratherapeutically anticoagulated patients. Conclusions- APT does not affect ICH characteristics and outcome in primary spontaneous ICH patients; however, it is associated with larger ICH volume and worse functional outcome in VKA-ICH, presumably by additive antihemostatic effects. Combination of anticoagulation and APT should, therefore, be diligently evaluated and restricted to the shortest possible time frame.

Predictors for occlusion of cerebral AVMs following radiation therapy : Radiation dose and prior embolization, but not Spetzler-Martin grade.

BACKGROUND: Intracranial arteriovenous malformations (AVMs) may show a harmful development. AVMs are treated by surgery, embolization, or radiation therapy. OBJECTIVE: This study investigated obliteration rates and side effects in patients with AVMs treated by radiation therapy. METHODS: A total of 40 cases treated between 2005 and 2013 were analyzed. Single-dose stereotactic radiosurgery (SRS) was received by 13 patients and 27 received hypofractionated stereotactic radiation therapy (HSRT). In 20 patients, endovascular embolization had been performed prior to irradiation and 24 patients (60 %) had a history of previous intracranial hemorrhage. RESULTS: Treatment resulted in complete obliteration (CO) in 23/40 cases and partial obliteration in 8/40. CO was achieved in 85 % of patients receiving SRS compared to 44 % of those receiving HSRT. In the HSRT group, a first indication of an influence of AVM volume on obliteration rate was found. Equivalent 2 Gy fraction doses (EQD2) >70 Gy showed an obliteration rate of 50 %. Prior embolization was significantly associated with a higher portion of CO (p = 0.032). Median latency period (24.2 vs. 26 months) until CO was similar in both groups (SRS vs. HSRT). The rate of intracranial hemorrhage in patients with no prior bleeding events was 0 %. CONCLUSION: Excellent obliteration rates were achieved by SRS. Consistent with the literature, this data analysis suggests that the results of HSRT are volume-dependent. Furthermore, regimens with EQD2 doses >70 Gy appear more likely to achieve obliteration than schemes with lower doses. The findings indicate that radiation therapy does not increase the risk of bleeding. Prior embolization may have a good prognostic impact.

Evaluation of a metal artifact reduction algorithm applied to post-interventional flat detector CT in comparison to pre-treatment CT in patients with acute subarachnoid haemorrhage.

OBJECTIVES: Metal artefacts can impair accurate diagnosis of haemorrhage using flat detector CT (FD-CT), especially after aneurysm coiling. Within this work we evaluate a prototype metal artefact reduction algorithm by comparison of the artefact-reduced and the non-artefact-reduced FD-CT images to pre-treatment FD-CT and multi-slice CT images. METHODS: Twenty-five patients with acute aneurysmal subarachnoid haemorrhage (SAH) were selected retrospectively. FD-CT and multi-slice CT before endovascular treatment as well as FD-CT data sets after treatment were available for all patients. The algorithm was applied to post-treatment FD-CT. The effect of the algorithm was evaluated utilizing the pre-post concordance of a modified Fisher score, a subjective image quality assessment, the range of the Hounsfield units within three ROIs, and the pre-post slice-wise Pearson correlation. RESULTS: The pre-post concordance of the modified Fisher score, the subjective image quality, and the pre-post correlation of the ranges of the Hounsfield units were significantly higher for artefact-reduced than for non-artefact-reduced images. Within the metal-affected slices, the pre-post slice-wise Pearson correlation coefficient was higher for artefact-reduced than for non-artefact-reduced images. CONCLUSION: The overall diagnostic quality of the artefact-reduced images was improved and reached the level of the pre-interventional FD-CT images. The metal-unaffected parts of the image were not modified. KEY POINTS: • After coiling subarachnoid haemorrhage, metal artefacts seriously reduce FD-CT image quality. • This new metal artefact reduction algorithm is feasible for flat-detector CT. • After coiling, MAR is necessary for diagnostic quality of affected slices. • Slice-wise Pearson correlation is introduced to evaluate improvement of MAR in future studies. • Metal-unaffected parts of image are not modified by this MAR algorithm.

Optimized Flat-Detector CT in Stroke Imaging: Ready for First-Line Use?

BACKGROUND: Using flat-detector CT (FD-CT) for stroke imaging has the advantage that both diagnostic imaging and endovascular therapy can be performed directly within the Angio Suite without any patient transfer and time delay. Thus, stroke management could be speeded up significantly, and patient outcome might be improved. But as precondition for using FD-CT as primary imaging modality, a reliable exclusion of intracranial hemorrhage (ICH) has to be possible. This study aimed to investigate whether optimized native FD-CT, using a newly implemented reconstruction algorithm, may reliably detect ICH in stroke patients. Additionally, the potential to identify ischemic changes was evaluated. METHODS: Cranial FD-CT scans were obtained in 102 patients presenting with acute ischemic stroke (n = 32), ICH (n = 45) or transient ischemic attack (n = 25). All scans were reconstructed with a newly implemented half-scan cone-beam algorithm. Two experienced neuroradiologists, unaware of clinical findings, evaluated independently the FD-CTs screening for hemorrhage or ischemic signs. The findings were correlated to CT, and rater and inter-rater agreement was assessed. RESULTS: FD-CT demonstrated high sensitivity (95-100%) and specificity (100%) in detecting intracerebral and intraventricular hemorrhage (IVH). Overall, interobserver agreement (κ = 0.92) was almost perfect and rater agreement to CT highly significant (r = 0.81). One infratentorial ICH and 10 or 11 of 22 subarachnoid hemorrhages (SAHs) were missed of whom 7 were perimesencephalic. The sensitivity for detecting acute ischemic signs was poor in blinded readings (0 or 25%, respectively). CONCLUSIONS: Optimized FD-CT, using a newly implemented reconstruction algorithm, turned out as a reliable tool for detecting supratentorial ICH and IVH. However, detection of infratentorial ICH and perimesencephalic SAH is limited. The potential of FD-CT in detecting ischemic changes is poor in blinded readings. Thus, plain FD-CT seems insufficient as a standalone modality in acute stroke, but within a multimodal imaging approach primarily using the FD technology, native FD-CT seems capable to exclude reliably supratentorial hemorrhage. Currently, FD-CT imaging seems not yet ready for wide adoption, replacing regular CT, and should be reserved for selected patients. Furthermore, prospective evaluations are necessary to validate this approach in the clinical setting.

Presence of Concomitant Systemic Cancer is Not Associated with Worse Functional Long-Term Outcome in Patients with Intracerebral Hemorrhage.

BACKGROUND: Data on clinical characteristics and outcome of patients with intracerebral hemorrhage (ICH) and concomitant systemic cancer disease are very limited. METHODS: Nine hundred and seventy three consecutive primary ICH patients were analyzed using our prospective institutional registry over a period of 9 years (2006-2014). We compared clinical and radiological parameters as well as outcome - scored using the modified Rankin Scale (mRS) and analyzed in a dichotomized fashion as favorable outcome (mRS = 0-3) and unfavorable outcome (mRS = 4-6) - of ICH patients with and without cancer. Relevant imbalances in baseline clinical and radiological characteristics were adjusted using propensity score (PS) matching. RESULTS: Prevalence of systemic cancer among patients with ICH was 8.5% (83/973). ICH patients with cancer were older (77 [70-82] vs. 72 [63-80] years; p = 0.002), had more often prior renal dysfunction (19/83 [22.9%] vs.107/890 [12.0%]; p = 0.005), and smaller hemorrhage volumes (10.1 [4.8-24.3] vs. 15.3 [5.4-42.9] mL; p = 0.017). After PS-matching there were no significant differences neither in mortality nor in functional outcome both at 3 months (mortality: 33/81 [40.7%] vs. 55/158 [34.8%]; p = 0.368; mRS = 0-3: 28/81 [34.6%] vs. 52/158 [32.9%]; p = 0.797) and 12 months (mortality: 39/78 [50.0%] vs. 70/150 [46.7%]; p = 0.633; mRS = 0-3: 25/78 [32.1%] vs. 53/150 [35.3%]; p = 0.620) among patients with and without concomitant systemic cancer. ICH volume tended to be highest in patients with hematooncologic malignancy and smallest in urothelial cancer. CONCLUSIONS: Patients with ICH and concomitant systemic cancer on average are older; however, they show smaller ICH volumes compared to patients without cancer. Yet, mortality and functional outcome is not different in ICH patients with and without cancer. Thus, the clinical history or the de novo diagnosis of concomitant malignancies in ICH patients should not lead to unjustified treatment restrictions.

Influence of different reconstruction parameters in the visualization of intracranial stents using C-arm flat panel CT angiography: experience in an animal model.

BACKGROUND: C-arm flat panel computed tomography angiography (CA-CTA) is a relatively new imaging modality. Consequently, knowledge about postprocessing parameters and their influence on image quality is still limited, especially for the visualization of implanted microstents. PURPOSE: To optimize reconstruction parameters by evaluating the influence of these different parameters for CA-CTA visualization of microstents in an animal model. MATERIAL AND METHODS: Eleven microstents were implanted within the left common carotid artery of 11 New Zealand white rabbits. Both CA-CTA, using intra-venous delivery of contrast material, and conventional digital subtraction angiography (DSA) was performed. CA-CTA datasets were reconstructed using three different image characteristics (normal, sharp, smooth). Two experienced neuroradiologists evaluated the image quality and performed measurements of inner and outer stent diameters as well as measurements of the lumen area. RESULTS: Stent deployment was performed successfully in all animals. Inter-observer correlation coefficient for all measurements was high (r = 0.87-0.92). Lumen area and inner stent diameter were significantly smaller in image characteristic "smooth" (P < 0.01) than in "sharp" and "normal". Outer stent diameter was larger in "smooth" than in "sharp" and "normal" (P < 0.01). Stent strut size was significantly wider using image characteristic "smooth". "Sharp" and "normal" compared best to DSA, with "sharp" providing the closest match to DSA measurements, with the trade-off of significantly more noise than in the "normal" reconstructions. CONCLUSION: The use of different image characteristics in the postprocessing of CA-CTA datasets has an influence on the visualization of implanted stents. Image characteristic "sharp" and "normal" compared best to DSA.

Impact of Perihemorrhagic Edema on Short-Term Outcome After Intracerebral Hemorrhage.

BACKGROUND: Intracerebral hemorrhage (ICH) is a devastating disease with ICH volume being the main predictor of poor outcome. The prognostic role of perihemorrhagic edema (PHE) is still unclear; however, available data are mainly derived from analyses during the first days after symptom onset. As PHE growth may continue up to 14 days after ICH, we evaluated PHE over a longer period of time and investigated its impact on short-term clinical outcome. METHODS: In this monocentric retrospective cohort study, patients with spontaneous supratentorial ICH were identified from our institutional data base. Different time points of CT scans were merged to time clusters for better comparison (day 1, 2-3, 4-6, 7-9, 10-12). Absolute volumes of ICH and PHE were obtained using a validated semiautomatic volumetric algorithm. Clinical outcome at discharge was assessed using the modified Rankin Scale (0-3 = favorable, 4-6 = poor). RESULTS: 220 patients (83 with favorable, 137 with poor outcome) were included in the final analysis. Mean ICH volume on admission was 22.8 [standard deviation (SD) 24.6] cm(3). Mean absolute PHE volume on admission was 22.5 (SD 20.8) cm(3) and increased to a mean peak volume of 38.1 (SD 31.4) cm(3) during 6.7 (SD 4.1) days on average. Besides GCS on admission, functional status before ICH, peak hematoma volume, lobar localization and fever burden, and high peak PHE volume predicted poor outcome at discharge [OR 0.977 (95 % CI 0.957-0.998)] in the multivariable analysis. CONCLUSIONS: PHE may have a negative impact on short-term functional outcome after ICH and therefore represent a possible treatment target.

Time-Resolved C-Arm Computed Tomographic Angiography Derived From Computed Tomographic Perfusion Acquisition: New Capability for One-Stop-Shop Acute Ischemic Stroke Treatment in the Angiosuite.

BACKGROUND AND PURPOSE: Multimodal imaging using cone beam C-arm computed tomography (CT) may shorten the delay from ictus to revascularization for acute ischemic stroke patients with a large vessel occlusion. Largely because of limited temporal resolution, reconstruction of time-resolved CT angiography (CTA) from these systems has not yielded satisfactory results. We evaluated the image quality and diagnostic value of time-resolved C-arm CTA reconstructed using novel image processing algorithms. METHODS: Studies were done under an Institutional Review Board approved protocol. Postprocessing of data from 21 C-arm CT dynamic perfusion acquisitions from 17 patients with acute ischemic stroke were done to derive time-resolved C-arm CTA images. Two observers independently evaluated image quality and diagnostic content for each case. ICC and receiver-operating characteristic analysis were performed to evaluate interobserver agreement and diagnostic value of this novel imaging modality. RESULTS: Time-resolved C-arm CTA images were successfully generated from 20 data sets (95.2%, 20/21). Two observers agreed well that the image quality for large cerebral arteries was good but was more limited for small cerebral arteries (distal to M1, A1, and P1). receiver-operating characteristic curves demonstrated excellent diagnostic value for detecting large vessel occlusions (area under the curve=0.987-1). CONCLUSIONS: Time-resolved CTAs derived from C-arm CT perfusion acquisitions provide high quality images that allowed accurate diagnosis of large vessel occlusions. Although image quality of smaller arteries in this study was not optimal ongoing modifications of the postprocessing algorithm will likely remove this limitation. Adding time-resolved C-arm CTAs to the capabilities of the angiography suite further enhances its suitability as a one-stop shop for care for patients with acute ischemic stroke.

Cerebral aneurysm treatment using flow-diverting stents: in-vivo visualization of flow alterations by parametric colour coding to predict aneurysmal occlusion: preliminary results.

OBJECTIVES: After deployment of flow-diverting stents (FDS), complete aneurysm occlusion is not predictable. This study investigated whether parametric colour coding (PCC) could allow in vivo visualization of flow alterations induced by FDS and identify favourable or adverse flow modulations. METHODS: Thirty-six patients treated by FDS were analyzed. Preinterventional and postinterventional DSA-series were postprocessed by PCC and time-density curves (TDCs) were calculated. The parameters aneurysmal inflow, outflow, and relative time-to-peak (rTTP) were calculated. Preinterventional and postinterventional values were compared and related to occlusion rate. RESULTS: Postinterventional inflow showed a mean reduction of 37%, outflow of 51%, and rTTP a prolongation of 82%. Saccular aneurysm occlusion occurred if a reduction of at least 15% was achieved for inflow and 35% for outflow (sensitivity: 89%, specificity: 82%). Unchanged outflow and a slightly prolonged rTTP were associated with growth in one fusiform aneurysm. CONCLUSIONS: PCC allows visualization of flow alterations after FDS treatment, illustrating "flow diverting effects" by the TDC shape and indicating mainly aneurysmal outflow and lesser inflow changes. Quantifiable parameters (inflow, outflow, rTTP) can be obtained, thresholds for predicting aneurysm occlusion determined, and adverse flow modulations assumed. As a rapid intraprocedural tool, PCC might support the decision to implant more than one FDS. KEY POINTS: • After deployment of a flow-diverting stent, complete aneurysm occlusion is unpredictable. • Parametric colour coding offers new options for visualizing in vivo flow alterations non-invasively. • Quantifiable parameters, i.e., aneurysmal inflow/outflow can be obtained allowing prognostic stratification. • Rapid, intraprocedural application allows treatment monitoring, potentially contributing to patient safety.

Limited versus Whole-Brain Perfusion for the Indication of Thrombolysis in the Extended Time Window of Acute Cerebral Ischemia.

BACKGROUND: Perfusion computed tomography (PCT) has emerged as alternative to magnetic resonance imaging (MRI) for assessment of patients clinically qualifying for off-label thrombolysis within 4.5 to 9 hours after onset of ischemic stroke. However, disadvantage of PCT is its often limited anatomic coverage with only 2 or 3 slices when using a 4- to 64-section scanner. Our purpose was therefore to evaluate the value of 2- and 3-slice perfusion compared to whole-brain perfusion. METHODS: One hundred twenty-five patients undergoing MRI beyond 4.5 hours after symptom onset with supratentorial perfusion deficit were selected retrospectively. Accordingly to PCT slice positioning, 2 or 3 slices of the whole-brain perfusion weighted imaging data set were depicted. Volumes of infarct (using cerebral blood volume) and penumbra (using time-to-peak and cerebral blood volume) were calculated, and results were compared with 2- and 3-slice-derived volumes, respectively. RESULTS: Whole-brain imaging revealed a mismatch of more than 20% in 68.8% of patients (defined as 100%). Two-slice imaging detected a perfusion deficit in 72% and a mismatch in 48.8% (sensitivity = 70.9%). Three-slice imaging detected a perfusion deficit in 76% and a mismatch in 50.4% (sensitivity = 73.3%). Although there was no significant difference between 2- and 3-slice imaging (P > .23), both techniques revealed significantly less patients with mismatch compared to whole-brain coverage (P < .01). CONCLUSIONS: Two- and 3-slice imaging like obtained with PCT on most installed CT systems to assess perfusion deficits with subsequent mismatch calculation in acute stroke outside the 4.5-hour time window is significantly inferior to whole-brain coverage and, hence, has to be considered as a less-than-ideal solution.

Effective dose to patient measurements in flat-detector and multislice computed tomography: a comparison of applications in neuroradiology.

PURPOSE: Flat-detector CT (FD-CT) is used for a variety of applications. Additionally, 3D rotational angiography (3D DSA) is used to supplement digital subtraction angiography (DSA) studies. The aim was to measure and compare the dose of (1) standard DSA and 3D DSA and (2) analogous FD-CT and multislice CT (MSCT) protocols. METHODS: Using an anthropomorphic phantom, the effective dose to patients (according to ICRP 103) was measured on an MSCT and a flat-detector angiographic system using standard protocols as recommended by the manufacturer. RESULTS: (1) Evaluation of DSA and 3D DSA angiography protocols: ap.-lat. Standard/low-dose series 1/0.8 mSv, enlarged oblique projection 0.3 mSv, 3D DSA 0.9 mSv (limited coverage length 0.3 mSv). (2) Comparison of FD-CT and MSCT: brain parenchyma imaging 2.9 /1.4 mSv, perfusion imaging 2.3/4.2 mSv, temporal bone 0.2 /0.2 mSv, angiography 2.9/3.3 mSv, limited to the head using collimation 0.5/0.5 mSv. CONCLUSION: The effective dose for an FD-CT application depends on the application used. Using collimation for FD-CT applications, the dose may be reduced considerably. Due to the low dose of 3D DSA, we recommend using this technique to reduce the number of DSA series needed to identify working projections. KEY POINTS: Effective dose of FD-CT in comparison to MSCT is in comparable range. Collimation decreases the dose of FD-CT effectively. Effective dose of 3-D angiography is identical to 2-D DSA. Different FD-CT programs have different dose.

Comparison of vascular risk profile and clinical outcomes among patients with central (branch) retinal artery occlusion versus amaurosis fugax.

BACKGROUND: Retinal artery occlusions lead to sudden, painless vision loss, affecting millions globally. Despite their significance, treatment strategies remain unestablished, contrasting with acute ischemic stroke (AIS), where IVT has proven efficacy. Similar to AIS, retinal artery occlusions demand urgent evaluation and treatment, reflecting the principle "time is retina". Even for patients with transient monocular vision loss, also known as amaurosis fugax (AF), pertinent guidelines meanwhile recommend immediate emergency assessment in a specialized facility. However, data on the clinical benefit and comparability with persistent occlusions are missing. This study aimed to compare the results of a comprehensive stroke-workup among patients with persistent retinal artery occlusions (RAO), including both central retinal (CRAO) and branch retinal artery occlusion (BRAO) and those with AF. METHODS: Conducted at the University Hospital Giessen, Germany, this exploratory cross-sectional study enrolled patients with transient or permanent unilateral vision loss of non-arteritic origin. The primary outcome were differences between the two groups RAO and AF with regard to cardiovascular risk profiles and comorbidities, vascular and pharmacological interventions and clinical neurological and ophthalmological outcomes. Secondary outcome was a sub-group analysis of patients receiving IVT. RESULTS: Out of 166 patients assessed, 76 with RAO and 40 with AF met the inclusion criteria. Both groups exhibited comparable age, gender distribution, and cardiovascular risk profiles. Notably, RAO patients did not show significantly more severe vascular comorbidities than AF patients. However, AF patients received vascular interventions more frequently. Pharmacological intervention rates were similar across groups. RAO patients had slightly worse neurological outcomes, and IVT did not yield favorable ophthalmological outcomes within any observed patients. CONCLUSION: The study found similar vascular burden and risk factors in patients with RAO and AF, with implications for clinical workflows. IVT for RAO may only be effective in very early treatment windows. This emphasizes the need for public awareness and collaborative protocols between ophthalmologists and neurologists to improve outcomes.

Measurement of quantifiable parameters by time-density curves in the elastase-induced aneurysm model: first results in the comparison of a flow diverter and a conventional aneurysm stent.

BACKGROUND: Quantifiable parameters to evaluate the effectiveness of flow diverters (FDs) are desirable. We measured time-density curves (TDCs) and calculated quantifiable parameters in the rabbit elastase-induced aneurysm model after stent (Neuroform [NF]) and FD (Pipeline embolisation device [PED]) treatment. METHODS: Sixteen rabbit elastase-induced aneurysms were treated with FD (n = 9) or NF (n = 5). Angiography was performed before and after treatment and TDCs were created. The time to peak (TTP), the full width at half maximum (FWHM) and the average slope of the curve which represent the inflow (IF) and outflow (OF) were calculated. RESULTS: Mean values before treatment were TTP = 0.8 s, FWHM = 1.2 s, IF = 153.5 and OF = -54.9. After PED treatment, the TTP of 1.8 s and FWHM of 47.8 s were extended. The IF was 31.2 and the OF was -11.5 and therefore delayed. The values after NF treatment (TTP = 1.1 s, FWHM = 1.8 s, IF = 152.9, OF = -33.2) changed only slightly. CONCLUSION: It was feasible to create TDCs in the rabbit aneurysm model. Parameters describing the haemodynamic effect of PED and NF were calculated and were different according to the type of device used. These parameters could possibly serve as predictive markers for aneurysm occlusion.

Efficient drug-delivery using magnetic nanoparticles--biodistribution and therapeutic effects in tumour bearing rabbits.

To treat tumours efficiently and spare normal tissues, targeted drug delivery is a promising alternative to conventional, systemic administered chemotherapy. Drug-carrying magnetic nanoparticles can be concentrated in tumours by external magnetic fields, preventing the nanomaterial from being cleared by metabolic burden before reaching the tumour. Therefore in Magnetic Drug Targeting (MDT) the favoured mode of application is believed to be intra-arterial. Here, we show that a simple yet versatile magnetic carrier-system (hydrodynamic particles diameter <200nm) accumulates the chemotherapeutic drug mitoxantrone efficiently in tumours. With MDT we observed the following drug accumulations relative to the recovery from all investigated tissues: tumour region: 57.2%, liver: 14.4%, kidneys: 15.2%. Systemic intra-venous application revealed different results: tumour region: 0.7%, liver: 14.4 % and kidneys: 77.8%. The therapeutic outcome was demonstrated by complete tumour remissions and a survival probability of 26.7% (P=0.0075). These results are confirming former pilot experiments and implying a milestone towards clinical studies. FROM THE CLINICAL EDITOR: This team of investigators studied drug carrying nanoparticles for magnetic drug targeting (MDT), demonstrating the importance of intra-arterial administration resulting in improved clinical outcomes in the studied animal model compared with intra-venous.

Rendezvous intervention using combined surgical carotid endarterectomy followed by endovascular thrombectomy in patients with acute tandem occlusions: a proof-of-concept experience at a tertiary care center.

BACKGROUND: Endovascular thrombectomy (EVT) is highly effective in acute stroke patients with intracranial large vessel occlusion (LVO), however, presence of concomitant cervical occlusion of the internal carotid artery (ICA) may limit the endovascular access. This study describes feasibility and efficacy of a surgical carotid access (cutdown) to perform interdisciplinary recanalization therapy including carotid endarterectomy (CEA) followed by EVT for recanalization of intracranial LVO in stroke patients with tandem occlusions. METHODS: We identified stroke patients with tandem occlusions who underwent a combined surgical-endovascular approach over a 5-year period. Surgical cutdown was provided by a cardiovascular surgery team at the angio-suite followed by EVT performed by the neuroradiological team. Demographics, stroke characteristics, treatments including antithrombotic management, procedure times, and clinical follow-up were assessed. RESULTS: Four patients with acute stroke because of tandem occlusions received CEA followed by EVT (two patients after frustrating femoral catheterization, two as first-line approach). Successful recanalization (TICI ≥ 2b) via endovascular thrombectomy was achieved in all patients at a median of 28 min after successful surgical CEA. Intraprocedural complication was observed in one case (25%; i.e. ICA dissection). CONCLUSIONS: This small study provides evidence that a combined interdisciplinary approach of CEA followed by EVT in the angio-suite in acute stroke patients with tandem occlusions is a feasible procedure in patients otherwise not accessible to endovascular recanalizing therapy and, therefore, high likelihood of developing large hemispheric infarction. Prospective data are warranted to identify patients who benefit from this combined approach as first-line therapy.

The hyperintense acute reperfusion marker on fluid-attenuated inversion recovery magnetic resonance imaging is caused by gadolinium in the cerebrospinal fluid.

BACKGROUND AND PURPOSE: The hyperintense acute reperfusion marker (HARM) on fluid-attenuated inversion recovery MRI is believed to be caused by gadolinium-based contrast agents crossing a disrupted blood-brain barrier. However, this hypothesis has never been directly verified in humans. METHODS: In this study, we analyzed cerebrospinal fluid samples of patients with HARM on imaging regarding the presence and concentration of gadolinium-based contrast agents. RESULTS: Gadobutrol was found in concentrations of approximately 50 µmol/L. Using phantom MRI experiments, we demonstrate that the detected concentrations are consistent with the observed HARM imaging pattern. CONCLUSIONS: Our study yields first direct evidence in humans that the imaging phenomenon HARM is indeed caused by leakage of gadolinium-based contrast agents into the cerebrospinal fluid.

Angiographic CT with intravenous contrast agent application for monitoring of intracranial flow diverting stents.

INTRODUCTION: Intracranial flow diverting devices are increasingly used to treat cerebral aneurysms. A reliable, non-invasive follow-up modality would be desirable. Our aim was to compare intra-arterial digital subtraction angiography (ia DSA) to angiographic computed tomography with intravenous contrast agent application (iv ACT) in the visualisation of flow diverting devices and aneurysm lumina. METHODS: Follow-up monitoring by iv ACT (n = 36) and ia DSA (n = 25) in 14 patients treated with flow diverting devices for intracranial aneurysms was evaluated retrospectively. Images were evaluated by two neuroradiologists in anonymous consensus reading regarding the device deployment, wall apposition, neck coverage of the aneurysm, opacification of the vessel and device lumen, as well as the degree of aneurysm occlusion. RESULTS: Corresponding ia DSA and iv ACT images were scored identically in all patients regarding the stent deployment, wall apposition and neck coverage, as well as the degree of aneurysm occlusion and patency status of the device and parent artery. Opacification of the parent vessel lumen and perfused parts of the aneurysm was considered slightly inferior for iv ACT in comparison with ia DSA (seven of 36 cases), without impact on diagnosis. CONCLUSIONS: We demonstrated the feasibility and diagnostic value of iv ACT in follow-up imaging of intracranial flow diverting devices. Due to its high spatial resolution and non-invasive character, this novel technique might become a valuable imaging modality in these patients.

Changes of radial diffusivity and fractional anisotropy in the optic nerve and optic radiation of glaucoma patients.

Purpose of this study was to evaluate with diffusion-tensor imaging (DTI) changes of radial diffusivity (RD) and fractional anisotropy (FA) in the optic nerve (ON) and optic radiation (OR) in glaucoma and to determine whether changes in RD and FA correlate with disease severity. Therefore, glaucoma patients and controls were examined using 3T. Regions of interest were positioned on RD and FA maps, and mean values were calculated for ON and OR and correlated with optic nerve atrophy and reduced spatial-temporal contrast sensitivity (STCS) of the retina. We found, that RD in glaucoma patients was significantly higher in the ON (0.74 ± 0.21 versus 0.58 ± 0.17·10(-3) mm(2) s(-1); P < 0.05) and OR (0.79 ± 0.23 versus 0.62 ± 0.14·10(-3) mm(2) s(-1); P < 0.05) compared to controls. Aside, FA was significantly decreased (0.48 ± 0.15 versus 0.66 ± 0.12 and 0.50 ± 0.20 versus 0.66 ± 0.11; P < 0.05). Hereby, correlation between changes in RD/FA and optic nerve atrophy/STCS was observed (r > 0.77). In conclusion, DTI at 3 Tesla allows robust RD and FA measurements in the ON and OR. Hereby, the extent of RD increase and FA decrease in glaucoma correlate with established ophthalmological examinations.