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Background: The thalamus plays an essential role in cognition. Cognitive deficits have to date mostly been studied retrospectively in chronic thalamic stroke in small cohorts. Studies prospectively evaluating the evolution of cognitive deficits and their association with thalamic stroke topography are lacking. This knowledge is relevant for targeted patient diagnostics and rehabilitation. Methods: Thirty-seven patients (57.5±17.5 [mean±SD] years, 57% men) with first-ever acute isolated ischemic stroke covering the anterior (n=5), paramedian (n=12), or inferolateral (n=20) thalamus and 37 in-patient controls without stroke with similar vascular risk factors matched for age and sex were prospectively studied. Cognition was evaluated using predefined tests at 1, 6, 12, and 24 months. Voxel-based lesion-symptom mapping was used to determine associations between neuropsychological deficits and stroke topography. Results: Patients with anterior thalamic stroke revealed severe deficits in verbal memory (median T score [Q1–Q3]: 39.1 [36.1–44.1]), language (31.8 [31.0–43.8]), and executive functions (43.8 [35.5–48.1]) at 1 month compared with controls (verbal memory: 48.5 [43.6–61.0], language: 55.7 [42.3–61.1], executive functions: 51.3 [50.1–56.8]). Patients with paramedian thalamic stroke showed moderate language (44.7 [42.8–55.9]) and executive (49.5 [44.3–55.1]) deficits and no verbal memory deficits (48.1 [42.5–54.7]) at 1 month compared with controls (59.0 [47.0–64.5]; 59.6 [51.1–61.3]; 52.5 [44.2–55.3]). The language and executive deficits in paramedian thalamic stroke patients almost completely recovered during follow-up. Intriguingly, significant deficits in verbal memory (44.7 [41.5–51.9]), language (47.5 [41.8–54.1]), and executive functions (48.2 [46.2–59.7]) were found in inferolateral thalamic stroke patients at 1 month compared with controls (50.5 [46.7–59.9]; 57.0 [51.2–62.9]; 57.4 [51.2–60.7]). Language, but not executive deficits persisted during follow-up. Voxel-based lesion-symptom mapping revealed an association of verbal memory deficits with anterior thalamus lesions and an association of non-verbal memory, language, and executive deficits with lesions at the anterior/paramedian/inferolateral border. Conclusions: All 3 stroke topographies exhibited significant deficits in diverse cognitive domains, which recovered to a different degree depending on the stroke localization. Our study emphasizes the need for comprehensive neuropsychological diagnostics to secure adequate patient rehabilitation.

Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. The objective of this study was to evaluate the image quality and diagnostic reliability of knee MRI performed at 0.55T compared with 1.5T. Methods: A total of 20 volunteers (9 female, 11 male; mean age = 42 years) underwent knee MRI on a 0.55T system (MAGNETOM Free.Max, Siemens Healthcare, Erlangen, Germany; 12-channel Contour M Coil) and a 1.5T scanner (MAGNETOM Sola, Siemens Healthcare, Erlangen, Germany; 18-channel transmit/receive knee coil). Standard two-dimensional (2D) turbo spin echo (TSE), fat-suppressed (fs) proton density-weighted (PDw), T1w TSE, and T2w TSE sequences were acquired in approximately 15 min. In total, 2 radiologists blinded to the field strength subjectively assessed all MRI sequences (overall image quality, image noise, and diagnostic quality) using a 5-point Likert scale (1–5; 5 = best). Additionally, both radiologists evaluated the possible pathologies of menisci, ligaments, and cartilage. Contrast ratios (CRs) of different tissues (bone, cartilage, and menisci) were determined on coronal PDw fs TSE images. The statistical analysis included Cohen’s kappa and the Wilcoxon rank sum test. Results: The overall image quality of the 0.55T T2w, T1w, and PDw fs TSE sequences was diagnostic and rated similar for T1w (p > 0.05), but lower for PDw fs TSE and T2w TSE compared with 1.5T (p < 0.05). The diagnostic accordance of meniscal and cartilage pathologies at 0.55T was similar to 1.5T. The CRs of the tissues were not significantly different between 1.5T and 0.55T (p > 0.05). The inter-observer agreement of the subjective image quality was generally fair between both readers and almost perfect for the pathologies. Conclusions: Deep learning-reconstructed TSE imaging at 0.55T yielded diagnostic image quality for knee MRI compared with standard 1.5T MRI. The diagnostic performance of meniscal and cartilage pathologies was equal for 0.55T and 1.5T without a significant loss of diagnostic information.

BACKGROUND AND PURPOSE: Detailed insight into the composition of thrombi retrieved from patients with ischemic stroke by mechanical thrombectomy might improve pathophysiologic understanding and therapy. Thus, this study searched for links between histologic thrombus composition and stroke subtypes and mechanical thrombectomy results. MATERIALS AND METHODS: Thrombi from 85 patients who had undergone mechanical thrombectomy for acute ischemic stroke between December 2016 and March 2018 were studied retrospectively. Thrombi were examined histologically. Preinterventional imaging features, stroke subtypes, and interventional parameters were re-analyzed. Statistical analysis was performed with the Kruskal-Wallis test, Mann-Whitney U test, or Spearman correlation as appropriate. RESULTS: Cardioembolic thrombi had a higher percentage of macrophages and a tendency toward more platelets than thrombi of large-artery atherosclerotic stenosis (P = .021 and .003) or the embolic stroke of undetermined source (P = .037 and .099) subtype. Thrombi prone to fragmentation required the combined use of contact aspiration and stent retrieval (P = .021) and were associated with an increased number of retrieving maneuvers (P = .001), longer procedural times (P = .001), and a higher lymphocyte content (P = .035). CONCLUSIONS: We interpreted the higher macrophage and platelet content in cardioembolic thrombi compared with large-artery atherosclerotic stenosis or embolic stroke of undetermined source thrombi as an indication that the latter type might be derived from an atherosclerotic plaque rather than from an undetermined cardiac source. The extent of thrombus fragmentation was associated with a more challenging mechanical thrombectomy and a higher lymphocyte content of the thrombi. Thus, thrombus fragmentation not only might be caused by the recanalization procedure but also might be a feature of a lymphocyte-rich, difficult-to-retrieve subgroup of thrombi.

Rationale and Objectives This retrospective single-center study aims to evaluate endovascular therapy (EVT) of cranial dural arteriovenous fistulas (dAVF) with ethylene vinyl alcohol (EVOH) copolymer (Onyx) regarding occlusion rates, complications, and recurrences. Material and Methods From January 2008 to April 2018, 75 patients with dAVF (41 men, 34 women; mean age 56 years) underwent EVT with the nonadhesive liquid embolic agent as primary treatment. Patient records and angiograms were reviewed for demographic data, symptoms, fistula type and size, number of EVTs, amount of embolic material, occlusion rates, and recurrences. Results Seventy-five patients with dAVFs were primarily embolized with EVOH in 96 EVTs. According to the Merland-Cognard classification the majority of dAVFs treated were type 4 (42.7%), followed by type 2a (18.7%), type 2a+b (17.3%), type 1 (8%), type 2b (5.3%), type 3 (5.3%), and type 5 (2.7%). Complete occlusion (CO) of the dAVF was achieved in 45/75 (60%) of cases after a single EVT and in 58 (77%) patients after one or several EVTs. Seven patients (9%) required additional surgical therapy for CO. Successful treatment was achieved for 70/75 (93%) patients including 10 (13%) patients with residual dAVFs type 1–2a. Recurrence after CO occurred in one (1.3%) patient and four (5.3%) patients remained refractory to therapy with dAVFs type > 2a. Procedure-related permanent morbidity occurred in 4/75 (5.3%) patients. Conclusion For more than a decade transarterial EVOH embolization has established as the first-line treatment for cranial dAVFs with high cure rates and low rates of complications and recurrences. Additional neurosurgical therapy is rarely required for curative treatment.

Background: Computer-aided diagnosis is increasingly used in radiology and may support not only unexperienced readers but also senior radiologists. It appears promising, especially in the sometimes challenging detection of early ischemic changes in stroke CT. Purpose: To compare the new post-processing software prototype Frontier_ASPECTS against two senior radiologists in ASPECTS evaluation. Material and Methods: Retrospectively, pre-interventional CTs of 100 patients, who underwent endovascular revascularization for acute middle cerebral artery ischemia, were blindly re-analyzed with respect to ASPECTS by two neuroradiologists (separately and in consensus) and by use of Frontier_ASPECTS. In addition to a fully automatic Frontier_ASPECTS reading (Frontier_1), Frontier_ASPECTS readings subsequently manually corrected for old cerebral defects (Frontier_2a), the affected hemisphere (known from CT angiography, Frontier_2b), and both (Frontier_3) were assessed. Statistical analysis was performed by intraclass correlation and Bland–Altman analysis. Results: Median ASPECTS was 10 for Frontier_3 (range = 5–10), 10 for radiologist_1 (range = 4–10), 9 for radiologist_2 (range = 2–10), and 10 for consensus reading (range = 2–10). All Frontier_ASPECTS variants correlated lowly with consensus reading (Frontier_1, r = 0.281; Frontier_2a, r = 0.357; Frontier_2b, r = 0.333; Frontier_3, r = 0.350; always P

Mechanical thrombectomy is common practice in proximal anterior vessel occlusion. However, it remains unclear whether peripheral artery occlusions should be treated as well. This retrospective study aimed to prove the effectiveness of endovascular recanalization treatment for the M2 segment by comparison of intracranial internal carotid artery (ICA), M1 segment, and M2 segment thrombectomy.All patients who received endovascular treatment for distal ICA, M1, or M2 segment occlusions between January 2010 and July 2017 at our center were re-analyzed with respect to reperfusion success, interventional and clinical parameters. Statistical analysis was performed by Mann Whitney test, Chi square test, and Spearman correlation analysis.A total of 261 patients (median age, 72 years), 100 with ICA, 137 with M1, and 24 with M2 segment occlusion, were included. Duration of endovascular treatment was significantly longer in ICA occlusions (median, 83 minutes, p0.001) compared to M1 (56 minutes) or M2 segment occlusions (49 minutes). Recanalization and reperfusion success and rate of endovascular complications did not differ between occlusion sites (AOL, p = 0.071; mTICI, p = 0.540; complications, p = 0.064). No significant difference in revascularization success was found between the different thrombectomy devices (direct thrombus aspiration, stent retrieving, or a sequential combined approach; p = 0.112). Successful M2 recanalization (mTICI 2b-3) correlated significantly with stronger posttherapeutic NIHSS reduction (r = 0.691, p0.001).We found endovascular treatment of M2 segment occlusions as safe and successful as endovascular therapy of the ICA or M1 segment, with stronger posttherapeutic NIHSS reduction after successful compared to insufficient M2 recanalization.

BACKGROUND: Amino acid positron emission tomography (PET) and magnetic resonance spectroscopy (MRS) are at the forefront of non-invasive imaging techniques used for detection and subtyping of glioma-suspicious lesions. No reported studies so far attempted to compare those techniques performed during one single preoperative session in their ability to predict glioma subtypes. METHODS: Twenty patients with histologically confirmed newly diagnosed glioma underwent preoperative MET PET and MRS during one single diagnostic session. According to the molecular portfolio and histopathological diagnosis, patients were subdivided in isocitrate dehydrogenase (IDH) wildtype glioblastoma (GBM), IDH wildtype grade II/III glioma (IDHW), IDH mutant grade II/III glioma without 1p/19q codeletion (IDHMnc) and with 1p/19q codeletion (IDHMcod). Maximum tumor-to-brain ratio (TBRmax), creatine, choline and N-acetyl aspartate (NAA) peaks were correlated with postoperative histopathological tumor diagnoses. To gain generalizable implications from our data we subdivided the full study cohort into a development and validation subcohort. A support vector machine model was fitted to the development subcohort and evaluated on the validation subcohort. Receiver operating characteristic (ROC) curve with area under the curve (AUC) as metric served to assess model performance. RESULTS: TBRmax was highest in GBM patients (4.18), followed by IDHW patients (3.04). The latter TBRmax values were higher compared to those in IDHMnc patients (1.95) and in IDHMcod patients (2.79). MRS marker distribution showed no clear trend. ROC analysis revealed TBRmax to be the best performing parameter in identifying IDH status (AUC: 0.67) and all spectroscopy markers combined in identifying glioma subgroups (AUC: 0.68). CONCLUSIONS: MET PET and MRS bear limited potential in glioma subgrouping. However, MET PET appears to be slightly superior in differentiating IDH status. Investigation in a larger cohort is required to draw definite conclusions.

BACKGROUND AND PURPOSE: Arterial transdural blood supply is a rare angiographic phenomenon in cerebral AVMs. This study aimed to evaluate angiographic transdural blood supply characteristics and to describe the clinical peculiarities of these lesions. MATERIALS AND METHODS: A prospective AVM data base of 535 patients, enrolled from 1990 to 2016, was analyzed retrospectively. Clinical information was reviewed through patients9 medical charts and radiologic studies. Patients with previous AVM treatment were excluded (n = 28). RESULTS: Patients with (n = 32, male/female ratio = 10:22; mean age, 46 ± 15 years; range, 13–75 years) and without transdural blood supply (n = 475, male/female ratio = 260:215; mean age, 40 ± 18 years; range, 2–87 years) did not show significant differences in clinical presentation (age, hemorrhage, seizures, chronic headache). The predominant nidus size in patients with transdural blood supply was ≥30 mm, with significantly more patients with large AVMs (>60 mm, P = .001). To describe the transdural blood supply, we used 3 grades based on the angiographic transdural blood supply proportion and intensity of AVM nidus perfusion (I–III). Fifty-seven percent of patients with chronic headache had a strong and substantial transdural nidus perfusion (III) and a high-flow transdural blood supply. CONCLUSIONS: Cerebral AVMs with transdural blood supply represent a rare and heterogeneous subgroup. Lesions can be graded by quantifying the transdural blood supply of the nidus and by capturing hemodynamic characteristics. The broad spread of angiographic features and comparable clinical patterns of patients with or without transdural blood supply raises questions about the relevance of the transdural blood supply to the natural history risk of an AVM and the intention for treatment.

Radiological assessment of brain tumors is widely based on the Radiology Assessment of Neuro-Oncology (RANO) criteria that consider non-specific T1 and T2 weighted images. Limitation of the RANO criteria is that they do not include metabolic imaging techniques that have been reported to be helpful to differentiate treatment related changes from true tumor progression. In the current study, we assessed if the combined use of MRI and PET with hybrid 11C–MET PET/MRI can improve diagnostic accuracy and diagnostic confidence of the readers to differentiate treatment related changes from true progression in recurrent glioma. Fifty consecutive patients with histopathologically proven glioma were prospectively enrolled for a hybrid 11C–MET PET/MRI to differentiate recurrent glioma from treatment induced changes. Sole MRI data were analyzed based on RANO. Sole PET data and in a third evaluation hybrid 11C–MET-PET/MRI data were assessed for metabolic respectively metabolic and morphologic glioma recurrence. Diagnostic performance and diagnostic confidence of the reader were calculated for the different modalities, and the McNemar test and Mann-Whitney U Test were applied for statistical analysis. Hybrid 11C–MET PET/MRI was successfully performed in all 50 patients. Glioma recurrence was diagnosed in 35 of the 50 patients (70%). Sensitivity and specificity were calculated for MRI (86.11% and 71.43%), for 11C–MET PET (96.77% and 73.68%), and for hybrid 11C–MET-PET/MRI (97.14% and 93.33%). For diagnostic accuracy hybrid 11C–MET-PET/MRI (96%) showed significantly higher values than MRI alone (82%), whereas no significant difference was found for 11C–MET PET (88%). Furthermore, by rating on a five-point Likert scale significantly higher scores were found for diagnostic confidence when comparing 11C–MET PET/MRI (4.26 ± 0,777) to either PET alone (3.44 ± 0.705) or MRI alone (3.56 ± 0.733). This feasibility study showed that hybrid PET/MRI might strengthen RANO classification by adding metabolic information to conventional MRI information. Future studies should evaluate the clinical utility of the combined use of 11C–MET PET/MRI in larger patient cohorts.

Background The reliable detection of intracranial hemorrhages is important, but just 1 year after the hemorrhage onset it might be missed using T2-weighted spin-echo and gradient-echo sequences. Susceptibility-weighted imaging (SWI) is a new magnetic resonance imaging sequence that is extremely sensitive in hemorrhage detection and that might improve the detection of hemorrhages over time. Purpose To investigate whether the detectability of intracranial blood and its degradation products is independent of the time span after intracranial hemorrhage using SWI. Material and Methods Sixty-six consecutive patients (28 men, 38 women) with definitely known time point of intracranial hemorrhage and available SWI sequence (1.5 or 3 T) were analyzed retrospectively. Twenty-one patients had a SWI follow-up. All SWI images were assessed by two radiologists in consensus regarding hemorrhage visibility using a 5-point scale. Statistical analysis was performed using Spearman’s correlation test. Results Median time interval between hemorrhage and first available SWI measurement was 819 days (range, 0 days to 13.2 years). Nine of 66 patients had an isolated subarachnoid hemorrhage (iSAH) and were therefore analyzed separately. In eight of these nine patients the hemorrhage could clearly be detected, the remaining one had minor iSAH. Spearman analysis showed no significant correlation between time span and visibility ( P = 0.660). In the remaining 57 patients (no iSAH) the hemorrhage was always visible achieving at least 3/5 points on the 5-point scale, and Spearman’s analysis revealed only a weak correlation between time span and visibility (r = 0.493, P Conclusion The detectability of blood and its degradation products using SWI is reliably possible over a long period after intracranial hemorrhage.

The aim of this study was to describe lesion patterns, distribution, and evolution in posterior reversible encephalopathy syndrome (PRES) in a larger single-center population. Scans and follow-up, if available, of 50 patients with PRES between 2002 and 2011 were reviewed retrospectively. Lesion patterns, extent, and signal intensity changes were identified and graded on fluid-attenuated inversion recovery (FLAIR) and diffusion-weighted images. Hemorrhagic changes were identified on T2* or susceptibility-weighted images, and gadolinium enhancement on T1-weighted images was identified if available. The most frequently affected regions on FLAIR were the frontal lobes in 54 %, occipital lobes in 34.3 %, and parietal lobes in 31.0 % of cases, thus 65.3 % in the posterior regions. Temporal lobes were affected in 10.6 %, the cerebellum in 6.5 %, and basal ganglia in 1.6 %. Division into vascular supply showed involvement in the anterior circulation in 66.5 % and in the posterior circulation in 33.5 % of cases. On diffusion-weighted imaging (DWI), vasogenic edema was observed in 6.9 %, cytotoxic edema in 9.1 %, and both in 2 % of cases. In 31.9 %, there was shine through, and in 15.9 %, there was shine through as well as cytotoxic or vasogenic edema. Topologic distribution on DWI showed affection of the frontal lobes in 43.5 %, occipital lobes in 25.8 %, parietal lobes in 17.7 %, temporal lobes in 11.3 %, and cerebellum in 1.6 %. T2* or susceptibility-weighted images showed spot-like hemosiderin accumulation in 17.2 % of cases. In 23.1 %, enhancement was seen. Follow-up magnetic resonance imaging showed complete resolution in 66.6 % of patients. The spectrum of imaging findings in PRES is wide. Almost always subcortical and cortical structures are involved. Although posterior changes are prominent in this syndrome, frontal involvement is more frequent than posterior on FLAIR imaging and DWI. On DWI, mixed patterns are not uncommon. Reversibility generally takes place independent of DWI pathology. Hypertension was not a prognostic factor.

Purpose To intraindividually compare the delineation of intracranial arterial vasculature in nonenhanced versus contrast-enhanced magnetization prepared rapid gradient echo (MPRAGE) imaging at 7 Tesla (T). Materials and Methods Sixteen subjects were examined on a 7 T whole-body magnetic resonance system (Magnetom 7T) equipped with a 32-channel transmit/receive head coil. MPRAGE imaging was performed pre- and postcontrast after the application of 0.1 mmol/kg bodyweight gadobutrol. For qualitative analysis, the delineation of the intracranial arteries, overall image quality, and image impairment were assessed in the nonenhanced and contrast-enhanced datasets using a 5-point scale (5 = excellent to 1 = nondiagnostic). Additionally, contrast ratios (CR) of the middle cerebral artery in correlation to surrounding gray matter in nonenhanced and postcontrast images were obtained. For statistical analysis a Wilcoxon signed-rank test was applied. Results Nonenhanced MPRAGE imaging offered an excellent delineation of the central vessel segments of the anterior circulation (mean anterior circulation 4.6) and a moderate- to high-quality assessment of the vessels of the posterior circulation (mean posterior circulation 3.9). Vessel delineation was improved in all assessed segments in the contrast-enhanced datasets, except for the cavernous segment of the internal carotid artery. Quantitative analysis revealed a mild, nonsignificant increase in CR mean values of the M1 segment (CR nonenhanced 0.67; CR contrast-enhanced 0.69). Conclusion Our results demonstrate the high diagnostic value of nonenhanced 7 T MPRAGE imaging for the assessment of the intracranial arterial vasculature, with improved assessment of the peripheral segments because of the application of a contrast agent.

The objective of this study was to evaluate the potential of integrated 11C-MET PET/MR for response assessment of relapsed glioblastoma (GBM) receiving bevacizumab treatment. Eleven consecutive patients with relapsed GBM were enrolled for an integrated 11C-MET PET/MRI at baseline and at follow-up. Treatment response for MRI was evaluated according to Response Assessment in Neuro-oncology (RANO) criteria and integrated 11C-MET PET was assessed by the T/N ratio. MRI showed no patient with complete response (CR), six of 11 patients with PR, four of 11 patients with SD, and one of 11 patients with progressive disease (PD). PET revealed metabolic response in five of the six patients with partial response (PR) and in two of the four patients with stable disease (SD), whereas metabolic non-response was detected in one of the six patients with PR, in two of the four patients with SD, and in the one patient with PD. Morphological imaging was predictive for PFS and OS when response was defined as CR, PR, SD, and non-response as PD. Metabolic imaging was predictive when using T/N ratio reduction of >25 as discriminator. Based on the morphologic and metabolic findings of this study a proposal for applying integrated PET/MRI for treatment response in relapsed GBM was developed, which was significantly predictive for PFS and OS (P = 0.010 respectively 0,029, log). This study demonstrates the potential of integrated 11C-MET-PET/MRI for response assessment of GBM and the utility of combined assessment of morphologic and metabolic information with the proposal for assessing relapsed GBM.

One prerequisite for transferring ultra-high-field magnetic resonance imaging (MRI) (3T) into clinical diagnostic workup is a low rate of side effects. To our knowledge, publications of subjective acceptance and willingness to undergo examinations at3T are rare. We present first results from our research site.Exposure to 7 T whole-body MRI of head, extremities, or breast was assessed in 102 subjects. They judged sources of discomfort (examination duration, room temperature) and physiological sensations (vertigo, light flashes) on a 10-point scale, differentiating between examination phases: table stationary or moving. For comparison, the same questionnaire was completed by 43 of these subjects after undergoing a 1.5 T examination. Vertigo was the most pronounced sensation at 7 T with 5% rating it as very unpleasant (none at 1.5 T). This should be compared with the fact that the lengthy exam duration was regarded as even more uncomfortable. Compared to 1.5 T, average study duration at 7 T was roughly doubled, and 7 T elicited a wider range of complaints.Although the number of side effects is increased at 7 T compared to 1.5 T, 7 T was well tolerated by the majority of subjects. Further data collection is necessary for better understanding of these effects.

This study aimed to determine the yield of repetitive catheter angiography (digital subtraction angiography (DSA)) for the detection of causative vascular lesions in patients with nontraumatic subarachnoidal hemorrhage (SAH) and negative initial DSA. We hypothesize that a second DSA might be helpful to detect an initially occult bleeding source. We retrospectively evaluated 649 patients with acute SAH and invasive catheter angiographies between 2004 and 2012. In 90 SAH patients initial imaging was negative concerning a causative bleeding source. A total of 113 repetitive DSA were performed. Two neuroradiologists reanalyzed the initial imaging and the result of the reangiography independently. In 4/90 patients (4.5 %) bleeding source was first detected in the second or third DSA. In all other patients, no causative vascular lesion was found. Reasons for the initially false negative diagnostics were one dissecting aneurysm and thrombosis of three aneurysms within the acute phase of SAH. Repetitive DSA revealed the cause of SAH in 4.5 % of the cases. These findings have a therapeutic and prognostic impact. We think that at least a second DSA should be part of diagnostic work-up in patients with SAH and missing bleeding source, even considering the risk of an additional invasive angiography itself.

Background The risk of clinically apparent, periprocedural stroke after thoracic endovascular aortic repair (TEVAR) due to dislodgement and embolization of aortic debris from intravascular manipulation of guidewires, catheters, and large-bore delivery systems ranges between 2% and 6% and has been associated with increased postoperative mortality. The rate of clinically silent cerebral ischemia is yet unknown, but may be even higher. Methods Nineteen patients (13 male, 6 female) who underwent TEVAR were included into this descriptive study. Periprocedural apparent and silent cerebral ischemia was assessed by daily clinical neurologic assessment and serial cerebral diffusion-weighted magnetic resonance imaging (DW-MRI) at baseline and 5 days (median, interquartile range: 3.5) after the procedure. Results The TEVAR was successful in all patients without immediate clinically apparent neurologic deficits. Postinterventional cerebral DW-MRI detected a total of 29 new foci of restricted diffusion in 12 of 19 TEVAR patients (63%). Lesions were usually multiple (1 to 6 lesions per patient) and ranged in size between 15 mm 3 and 300 mm 3 ; 16 lesions were found in the left hemisphere, 13 lesions in the right hemisphere. Overstenting of the left subclavian artery was performed in 8 cases, but was not associated with lateralization of lesions. There were no additional apparent neurologic events during the in-hospital period. Conclusions Thoracic endovascular aortic repair resulted in a high incidence of new foci of restricted diffusion on cerebral DW-MRI in a pattern suggestive of periprocedural embolization. Although multiple lesions per patients were found, these lesions were not associated with apparent neurologic deficits during the in-hospital period. Further developments in TEVAR should be directed toward reducing the risk of periprocedural cerebral embolization.

Purpose New ischemic brain lesions are common findings after cerebral diagnostic angiography and endovascular therapy. Diffusion-weighted MRI (DWI) can be used for detection of these lesions. The aim of the present study was to investigate the incidence of DWI lesions after stent-assisted coiling and the evaluation of possible risk factors. Methods The study included a total of 75 consecutive patients treated with stent-assisted coiling. Post-procedural DWI of the brain was performed to detect ischemic lesions. Demographic data, aneurysm characteristics and angiographic parameters were correlated with properties of DWI lesions. Results In post-procedural DWI, 48 of the 75 patients (64%) had 163 DWI lesions in a pattern consistent with embolic events. The number of patients with DWI lesions was significantly increased in older patients (≥55 years) and longer intervention times (≥120 min). The ischemic brain volume was significantly increased in older patients (≥55 years) as well as in patients who were implanted with a shorter stent ( Conclusions Thromboembolic events are common after stent-assisted coiling with an incidence comparable to DWI studies after coiling alone. Despite several devices and low operator experience, stent-assisted coiling for intracranial aneurysms has a very low risk of permanent neurologic disability. Further studies are necessary to improve the safety of stent-assisted coiling for patients in conditions with increased risk potential (age, procedure time, stent length).

Workflow efficiency and workload of radiological technologists (RTs) were compared in head examinations performed with two 1.5 T magnetic resonance (MR) scanners equipped with or without an automated user interface called "day optimizing throughput" (Dot) workflow engine.Thirty-four patients with known intracranial pathology were examined with a 1.5 T MR scanner with Dot workflow engine (Siemens MAGNETOM Aera) and with a 1.5 T MR scanner with conventional user interface (Siemens MAGNETOM Avanto) using four standardized examination protocols. The elapsed time for all necessary work steps, which were performed by 11 RTs within the total examination time, was compared for each examination at both MR scanners. The RTs evaluated the user-friendliness of both scanners by a questionnaire. Normality of distribution was checked for all continuous variables by use of the Shapiro-Wilk test. Normally distributed variables were analyzed by Student's paired t-test, otherwise Wilcoxon signed-rank test was used to compare means.Total examination time of MR examinations performed with Dot engine was reduced from 24:53 to 20:01 minutes (P.001) and the necessary RT intervention decreased by 61% (P.001). The Dot engine's automated choice of MR protocols was significantly better assessed by the RTs than the conventional user interface (P = .001).According to this preliminary study, the Dot workflow engine is a time-saving user assistance software, which decreases the RTs' effort significantly and may help to automate neuroradiological examinations for a higher workflow efficiency.

To intraindividually compare the delineation of intracranial arterial vasculature in nonenhanced versus contrast-enhanced magnetization prepared rapid gradient echo (MPRAGE) imaging at 7 Tesla (T).Sixteen subjects were examined on a 7 T whole-body magnetic resonance system (Magnetom 7T) equipped with a 32-channel transmit/receive head coil. MPRAGE imaging was performed pre- and postcontrast after the application of 0.1 mmol/kg bodyweight gadobutrol. For qualitative analysis, the delineation of the intracranial arteries, overall image quality, and image impairment were assessed in the nonenhanced and contrast-enhanced datasets using a 5-point scale (5 = excellent to 1 = nondiagnostic). Additionally, contrast ratios (CR) of the middle cerebral artery in correlation to surrounding gray matter in nonenhanced and postcontrast images were obtained. For statistical analysis a Wilcoxon signed-rank test was applied.Nonenhanced MPRAGE imaging offered an excellent delineation of the central vessel segments of the anterior circulation (mean anterior circulation 4.6) and a moderate- to high-quality assessment of the vessels of the posterior circulation (mean posterior circulation 3.9). Vessel delineation was improved in all assessed segments in the contrast-enhanced datasets, except for the cavernous segment of the internal carotid artery. Quantitative analysis revealed a mild, nonsignificant increase in CR mean values of the M1 segment (CRnonenhanced 0.67; CRcontrast-enhanced 0.69).Our results demonstrate the high diagnostic value of nonenhanced 7 T MPRAGE imaging for the assessment of the intracranial arterial vasculature, with improved assessment of the peripheral segments because of the application of a contrast agent.

Lhermitte-Duclos disease (LDD; dysplastic cerebellar gangliocytoma) is a rare hamartomatous lesion of the cerebellar cortex and this was first described in 1920. LDD is considered to be part of the autosomal-dominant phacomatosis and cancer syndrome Cowden disease (CS). We examined the brain of a 46-year-old man, who displayed the manifestations of CS, with 7 Tesla (T) and 1.5T MRI and 1.5T MR spectroscopy ( 1 H-MRS). We discuss the possible benefits of employing ultrahigh-field MRI for making the diagnosis of this rare lesion.

In this study tumour vascularity and necrosis of intracranial astrocytomas were compared using 7 T and 1.5 T magnetic resonance imaging (MRI). Fifteen patients with histologically proven astrocytomas (WHO grades II–IV) were prospectively examined at 1.5 T (Magnetom Espree or Sonata) and 7 T (Magnetom 7 T, Siemens, Erlangen, Germany) with T2*-w (weighted), T1-w with (only a subset of five patients at 7 T) and without contrast medium, T2-w and proton-density (PD)-w MRI. Clinically used 1.5 T sequences were adapted to 7 T. Histological findings and T2*-w MR images at both field strengths were compared for the presence of assumed tumour microvascularity and necrosis. Two diffusely infiltrating astrocytomas, four anaplastic astrocytomas and nine glioblastomas were included. T2*-w images depicted susceptibility patterns representing presumed tumour microvascularity in 8 out of 15 (53%) gliomas at 7 T compared with 5 out of 15 (33%) gliomas at 1.5 T. Compared with 1.5 T MRI three additional necrotic tumour areas were depicted only on 7 T T2- and T2*-w images of one glioblastoma. On T1-w MR images, contrast enhancement of five out of five glioblastomas was similar at both field strengths. 7 T gradient-echo sequences provide excellent image contrast of presumed microvasculature and necrosis in astrocytomas.

The purpose of this study was to optimize and to evaluate 3D time-of-flight (TOF)-like non-contrast enhanced MR-angiography (MRA) techniques for display of the intracranial vessels on a 7 T whole-body scanner. Three different gradient echo sequences (TOF, VIBE, MPRAGE) were compared in 12 healthy volunteers and 13 patients. Two blinded senior radiologists independently rated the presence or absence of artefacts and the conspicuity of ten different vessel segments in source and maximum-intensity-projection (MIP) images. In source images, MPRAGE achieved the best results; even the fine vessels and the vessels near the air-containing mastoid were depicted very well. Intraluminal signal loss, which was a problem in the greater vessels in TOF and VIBE imaging, was less pronounced in MPRAGE images. In the MIP images, TOF performed best. Both VIBE and MPRAGE can generate TOF-like contrast and cover the whole brain in less than 15 min, whereas TOF covered only a subvolume of the brain. MPRAGE performed especially well in this 7 T imaging study. The accuracy of the sequence deserves further evaluation in patients with vessel stenoses and aneurysms.

An 81-year old female underwent percutaneous coronary intervention (PCI) because of atrial fibrillation on current anticoagulation with 100 mg aspirin/d. 48-hours following the procedure, the patient became hypotensive. Signs of hematoma at the puncture site in the right groin were recoded on general physical examination. The abdomen was distended with tenderness in the right iliac fossa. Additionally the patient suffered from stabbing pain in the right lower abdomen. The hemoglobin level fell from 13 to 8 g/dl. An abdominal CT scan performed with administration of intravenous contrast media revealed a large, biphasic right retroperitoneal hematoma (zone II) with a craniocaudal dimension of 22 cm (Figure 1). An active bleeding from the right external iliac artery was demonstrated by an ascending contrast extravasation (arrow) between the hematoma layers (serum/corpuscular part). The patient was managed by exploratory laparotomy. Intraoperative findings were significant for a retroperitoneal hematoma (RPH) with an injured right external iliac artery due to puncture wound and diffuse bleeding. These could be surgically controlled by running suture reconstruction of the artery lesion and subtly, retroperitoneal hemostasis.