Evolving Characteristics of Gadolinium-Based Contrast Agents for MR Imaging: A Systematic Review of the Importance of Relaxivity.

Gadolinium-based contrast agents (GBCAs) are widely and routinely used to enhance the diagnostic performance of magnetic resonance imaging and magnetic resonance angiography examinations. T1 relaxivity (r1) is the measure of their ability to increase signal intensity in tissues and blood on T1-weighted images at a given dose. Pharmaceutical companies have invested in the design and development of GBCAs with higher and higher T1 relaxivity values, and "high relaxivity" is a claim frequently used to promote GBCAs, with no clear definition of what "high relaxivity" means, or general concurrence about its clinical benefit. To understand whether higher relaxivity values translate into a material clinical benefit, well-designed, and properly powered clinical studies are necessary, while mere in vitro measurements may be misleading. This systematic review of relevant peer-reviewed literature provides high-quality clinical evidence showing that a difference in relaxivity of at least 40% between two GBCAs results in superior diagnostic efficacy for the higher-relaxivity agent when this is used at the same equimolar gadolinium dose as the lower-relaxivity agent, or similar imaging performance when used at a lower dose. Either outcome clearly implies a relevant clinical benefit. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 3.

[Large Language Models for Rapid Simplification of Quality Assurance Data Input: Field Trial with Real Data in the Context of Tumour Documentation in Urology]. / Large Language Modelle zur schnellen Vereinfachung der Eingabe von Qualitätssicherungsdaten: Performance-Test mit Echtdaten am Beispiel der Tumordokumentation in der Urologie.

INTRODUCTION: Large Language Models (LLMs) such as ChatGPT have rapidly brought the application of artificial intelligence into widespread use. Among many different use cases for text generation and processing, one application is the extraction of data from existing documents and conversations for simplified and automated form-filling. OBJECTIVE: In the field of quality assurance and documentation of cancer diseases, there is currently a significant workload involved in transferring data under various aspects into slightly varying formats and applying interpretations such as the TNM classification of tumours. However, there is a lack of trials with real data to assess the applicability of LLM-supported processes in this area, which would enable an evaluation of efficiency and practicality. This study aims to implement and assess such a trial. METHODOLOGY: A trial was conducted with N=153 privacy-compliant and ethics committee-cleared medical reports from 25 patients. Using the publicly available version of ChatGPT 4.0, an automated script was used to extract the date of initial diagnosis and common tumor classifications. The results were then individually checked for accuracy. Based on this, the utility of a simple system for guided support in tasks related to tumour documentation was assessed. Additionally, the approach was evaluated in terms of operational costs for the model and its applicability. RESULTS: In summary, the study concludes that the use of generative AI in this field is promising and suitable as a tool even in an untrained state. In a simplified calculation, costs of 35 cents are offset by a value creation of 61,54 euros. However, it also becomes clear that AI can only act in a supportive role, and the correct integration with pre-made specific prompts and tools into the workflow is crucial for a relevant performance. CONCLUSION: The use of generative AI in the context of search, transfer, and interpretation tasks in the creation of tumor documentation is a promising approach. However, its implementation in practical applications must be closely monitored, and the optimal interaction between man and machine should continue to be evaluated and must be accompanied by tools and task-specific prompts.

Potential effects of a mobile stroke unit on time to treatment and outcome in patients treated with thrombectomy or thrombolysis: A Danish-German cross-border analysis.

BACKGROUND AND PURPOSE: A mobile stroke unit (MSU) reduces delays in stroke treatment by allowing thrombolysis on board and avoiding secondary transports. Due to the beneficial effect in comparison to conventional emergency medical services, current guidelines recommend regional evaluation of MSU implementation. METHODS: In a descriptive study, current pathways of patients requiring a secondary transport for mechanical thrombectomy were reconstructed from individual patient records within a Danish (n = 122) and an adjacent German region (n = 80). Relevant timestamps included arrival times (on site, primary hospital, thrombectomy centre) as well as the initiation of acute therapy. An optimal MSU location for each region was determined. The resulting time saving was translated into averted disability-adjusted life years (DALYs). RESULTS: For each region, the optimal MSU location required a median driving time of 35 min to a stroke patient. Time savings in the German region (median [Q1; Q3]) were 7 min (-15; 31) for thrombolysis and 35 min (15; 61) for thrombectomy. In the Danish region, the corresponding time savings were 20 min (8; 30) and 43 min (25; 66). Assuming 28 thrombectomy cases and 52 thrombolysis cases this would translate to 9.4 averted DALYs per year justifying an annual net MSU budget of $0.8M purchasing power parity dollars (PPP-$) in the German region. In the Danish region, the MSU would avert 17.7 DALYs, justifying an annual net budget of PPP-$1.7M. CONCLUSION: The effects of an MSU can be calculated from individual patient pathways and reflect differences in the hospital infrastructure between Denmark and Germany.

Neuroradiological diagnosis and therapy of cerebral vasospasm after subarachnoid hemorrhage. / Neuroradiologische Diagnostik und Therapie von zerebralen Vasospasmen nach Subarachnoidalblutung.

BACKGROUND: Cerebral damage after aneurysmal subarachnoid hemorrhage (SAH) results from various, sometimes unrelated causes. After the initial hemorrhage trauma with an increase in intracranial pressure, induced vasoconstriction, but also microcirculatory disturbances, inflammation and pathological electrophysiological processes (cortical spreading depolarization) can occur in the course of the disease, resulting in delayed cerebral ischemia (DCI). In the neuroradiological context, cerebral vasospasm (CVS) remains the focus of diagnostic imaging and endovascular therapy as a frequent component of the genesis of DCI. METHODS: The amount of blood leaked during aneurysm rupture (which can be detected by CT, for example) correlates with the occurrence and severity of CVS. CT perfusion is then an important component in determining the indication for endovascular spasm therapies (EST). These include intra-arterial drug administration (also as long-term microcatheter treatment) and mechanical procedures (balloon angioplasty, vasodilatation using other instruments such as stent retrievers, stenting). CONCLUSION: This review summarizes the current findings on the diagnosis and treatment of CVS after aneurysmal SAH from a neuroradiological perspective, taking into account the complex and up-to-date international literature. KEY POINTS: · Vasospasm is a frequent component of the multifactorial genesis of delayed cerebral ischemia after SAH and remains the focus of diagnosis and treatment in the neuroradiological context.. · The initial extent of SAH on CT is associated with the occurrence and severity of vasospasm.. · CT perfusion is an important component in determining the indication for endovascular spasm therapy.. · Endovascular spasm therapies include local administration of medication (also as long-term therapies with microcatheters) and mechanical procedures (balloon angioplasty, dilatation using other devices such as stent retreivers, stenting).. CITATION FORMAT: · Neumann A, Schacht H, Schramm P. Neuroradiological diagnosis and therapy of cerebral vasospasm after subarachnoid hemorrhage. Fortschr Röntgenstr 2024; DOI: 10.1055/a-2266-3117.

Needle electromyography does not meaningfully impact findings in MR-neurography/-myography.

INTRODUCTION: Magnetic resonance neurography (MRN) and myography (MRM) are emerging imaging methods for detecting diseases of the peripheral nerve system (PNS). Most patients with PNS diseases also undergo needle electromyography (EMG). This study examined whether EMG led to lesions that were detectable using MRN/MRM and whether these lesions could impair image interpretation. METHODS: Ten patients who underwent clinically indicated EMG were recruited. MRN/MRM was performed before and 2-6 h after EMG, and if achievable, 2-3 days later. T2 signal intensity (SI) of the tibialis anterior muscle (TA) was quantified, and sizes and SI of the new lesions were measured. Visual rating was performed independently by three neuroradiologists. RESULTS: T2 lesions at the site of needle insertion, defined as focal edema, were detectable in 9/10 patients. The mean edema size was 31.72 mm2 (SD = 14.42 mm2 ) at the first follow-up. Susceptibility-weighted imaging lesions, defined as (micro) hematomas were detected in 5/10 patients (mean size, 23.85 mm2 [SD = 12.59 mm2 ]). General muscle SI of the TA did not differ between pre- and post-EMG examinations. Lesions size was relatively small, and the readers described image interpretation as not impaired by these lesions. DISCUSSION: This study showed that focal edema and hematomas frequently occurred after needle EMG and could be observed using MRN/MRM. As general muscle SI was not affected and image interpretation was not impaired, we concluded that needle EMG did not interfere with MRN/MRM.

Thrombectomy With the pRESET vs Solitaire Stent Retrievers as First-Line Large Vessel Occlusion Stroke Treatment: A Randomized Clinical Trial.

Importance: Stent retriever-based thrombectomy is highly beneficial in large vessel occlusion (LVO) strokes. Many stent retriever designs are currently available, but comparison of these technologies in well-conducted studies is lacking. Objective: To determine whether thrombectomy for LVO stroke with the pRESET stent retriever is noninferior to treatment with the Solitaire stent retriever. Design, Setting, and Participants: This study was a multicenter, prospective, randomized, controlled, open-label, adaptive, noninferiority trial with blinded primary end point evaluation. Between October 2019 and February 2022, multicenter participation occurred across 19 research hospitals and/or universities in the US and 5 in Germany. Patients with LVO stroke were enrolled and included up to 8 hours after symptom onset. Interventions: Patients underwent 1:1 randomization to thrombectomy with the pRESET or Solitaire stent retriever. Main Outcomes and Measures: The primary outcome was the difference in the rate of 90-day functional independence across the 2 devices, using a -12.5% noninferiority margin for the lower bound of the 1-sided 95% CI of the difference between pRESET and Solitaire retrievers. Results: Of 340 randomized patients, 170 (50.0%) were female, and the median (IQR) age was 73.0 (64.0-82.0) years. The study procedure was completed in 322 of the 340 randomized patients. The primary end point of 90-day functional independence was achieved by 95 patients (54.9%; 95% CI, 48.7-61.1) in the pRESET group and in 96 (57.5%; 95% CI, 51.2-63.8) in the Solitaire group (absolute difference, -2.57%; 95% CI, -11.42 to 6.28). As the lower bound of the 95% CI was greater than -12.5%, the pRESET retriever was deemed noninferior to the Solitaire retriever. The noninferiority of pRESET over Solitaire was also observed in the secondary clinical end point (90-day shift in modified Rankin Scale score) and in both angiographic end points (Expanded Treatment in Cerebral Infarction [eTICI] score of 2b50 or greater within 3 passes: 146 of 173 [84.4%] vs 149 of 167 [89.2%]; absolute difference, -4.83%; 95% CI, -10.84 to 1.19; eTICI of 2c or greater following the first pass: 76 of 173 [43.7%] vs 74 of 167 [44.3%]; absolute difference, -0.63%; 95% CI, -9.48 to 8.21). Symptomatic intracranial hemorrhage occurred in 0 patients in the pRESET group and 2 (1.2%) in the Solitaire group. Mortality occurred in 25 (14.5%) in the pRESET group and in 24 (14.4%) in the Solitaire group at 90 days. Findings of the per-protocol and as-treated analyses were in concordance with findings of the intention-to-treat analysis. Conclusions and Relevance: In this study, among patients with LVO stroke, thrombectomy with the pRESET stent retriever was noninferior to thrombectomy with the Solitaire stent retriever. Findings suggest that pRESET offers a safe and effective option for flow restoration and disability reduction in patients with LVO stroke.

Reversible intracranial contrast medium accumulation after embolization of unruptured cerebral aneurysms and its association with transient neurological deficits: A single center experience.

BACKGROUND: Use of iodine-containing contrast medium (CM) is obligatory for endovascular treatment (EVT) of cerebral aneurysms. After EVT, intracranial density increases (DIs) can be detected in cranial computed tomography (CT). Those DI can correspond to subarachnoid hemorrhage (SAH), infarction or reversible CM accumulation (RCMA). The latter can be mistaken for hemorrhage, especially if they are accompanied by neurological deficits. OBJECTIVE: To analyze postinterventional DI after EVT of unruptured cerebral aneurysms and associated clinical symptoms and to identify risk factors for the occurrence of RCMA. METHODS: For differentiation of DI, we compared CT scans following EVT and additionally 24 h ± 5 h later. Diagnosis of RCMA was based on marked regression of DI on follow-up scans. We analyzed continuous variables (age, duration of intervention and anesthesia, aneurysm diameter, amount of CM and renal function) and categorial variables (gender, aneurysm location, devices for EVT, antiplatelet therapy [APT] and associated neurological deficits) to identify risk factors for the occurrence of RCMA. RESULTS: We studied 58 patients (44 female, mean age 59.5 [range 39-81]) who underwent EVT for a total of 68 cerebral aneurysms in 62 therapy sessions over a 3-year period without periprocedural complications. Postinterventional DI occurred after 17 therapy sessions. All 17 DI turned out to be RCMA in the follow-up imaging. Two patients who had no DI on initial postinterventional CT showed new SAH on follow-up CT. Infarctions were not observed. Transient neurological deficits occurred in eight patients (12.9%) and were associated with RCMA (P = 0.010). Postinterventional RCMA was associated with the duration of EVT (P = 0.038) and with APT (acetylsalicylic acid [ASA] + clopidogrel: P =0.040; ASA alone: P =0.011). CONCLUSIONS: RCMA is common after EVT of unruptured cerebral aneurysms and often accompanied by transient neurological deficits. Long procedure duration and APT appear to predispose to the occurrence of RCMA.

Preserved Corticospinal Tract Revealed by Acute Perfusion Imaging Relates to Better Outcome After Thrombectomy in Stroke.

BACKGROUND: The indication for mechanical thrombectomy (MT) in stroke patients with large vessel occlusion has been constantly expanded over the past years. Despite remarkable treatment effects at the group level in clinical trials, many patients remain severely disabled even after successful recanalization. A better understanding of this outcome variability will help to improve clinical decision-making on MT in the acute stage. Here, we test whether current outcome models can be refined by integrating information on the preservation of the corticospinal tract as a functionally crucial white matter tract derived from acute perfusion imaging. METHODS: We retrospectively analyzed 162 patients with stroke and large vessel occlusion of the anterior circulation who were admitted to the University Medical Center Lübeck between 2014 and 2020 and underwent MT. The ischemic core was defined as fully automatized based on the acute computed tomography perfusion with cerebral blood volume data using outlier detection and clustering algorithms. Normative whole-brain structural connectivity data were used to infer whether the corticospinal tract was affected by the ischemic core or preserved. Ordinal logistic regression models were used to correlate this information with the modified Rankin Scale after 90 days. RESULTS: The preservation of the corticospinal tract was associated with a reduced risk of a worse functional outcome in large vessel occlusion-stroke patients undergoing MT, with an odds ratio of 0.28 (95% CI, 0.15-0.53). This association was still significant after adjusting for multiple confounding covariables, such as age, lesion load, initial symptom severity, sex, stroke side, and recanalization status. CONCLUSIONS: A preinterventional computed tomography perfusion-based surrogate of corticospinal tract preservation or disconnectivity is strongly associated with functional outcomes after MT. If validated in independent samples this concept could serve as a novel tool to improve current outcome models to better understand intersubject variability after MT in large vessel occlusion stroke.

Evaluation of DeGIR registry data on endovascular treatment of cerebral vasospasm in Germany 2018-2021: an overview of the current care situation. / Auswertung der DeGIR-Registerdaten zur endovaskulären Therapie von zerebralen Vasospasmen in Deutschland 2018­2021: Ein Überblick über die aktuelle Versorgungssituation.

BACKGROUND: Evaluation of endovascular therapies for cerebral vasospasm (CVS) documented in the DeGIR registry from 2018-2021 to analyse the current clinical care situation in Germany. METHODS: Retrospective analysis of the clinical and procedural data on endovascular spasm therapies (EST) documented anonymously in the DeGIR registry. We analysed: pre-interventional findings of CTP and consciousness; radiation dose applied, interventional-technical parameters (local medication, devices, angiographic result), post-interventional symptoms, complications and mortality. RESULTS: 3584 patients received a total of 7628 EST (median age/patient: 53 [range: 13-100, IQR: 44-60], 68.2 % women) in 91 (2018), 92 (2019), 100 (2020) and 98 (2021) centres; 5388 (70.6 %) anterior circulation and 378 (5 %) posterior circulation (both involved in 1862 cases [24.4 %]). EST was performed once in 2125 cases (27.9 %), with a mean of 2.1 EST/patient. In 7476 times, purely medicated EST were carried out (nimodipine: 6835, papaverine: 401, nitroglycerin: 62, other drug not specified: 239; combinations: 90). Microcatheter infusions were documented in 1132 times (14.8 %). Balloon angioplasty (BA) (additional) was performed in 756 EST (9.9 %), other mechanical recanalisations in 154 cases (2 %) and stenting in 176 of the EST (2.3 %). The median dose area product during ET was 4069 cGycm² (drug: 4002/[+]BA: 8003 [p < 0.001]). At least 1 complication occurred in 95 of all procedures (1.2 %) (drug: 1.1 %/[+]BA: 4.2 % [p < 0.001]). Mortality associated with EST was 0.2 % (n = 18). After EST, overall improvement or elimination of CVS was found in 94.2 % of cases (drug: 93.8 %/[+]BA: 98.1 % [p < 0.001]). In a comparison of the locally applied drugs, papaverine eliminated CVS more frequently than nimodipine (p = 0.001). CONCLUSION: EST have a moderate radiation exposure and can be performed with few complications. Purely medicated EST are predominantly performed, especially with nimodipine. With (additional) BA, radiation exposure, complication rates and angiographic results are higher or better. When considering drug EST alone, there is evidence for an advantage of papaverine over nimodipine, but a different group size has to be taken into account. In the analysis of EST, the DeGIR registry data are suitable for answering more specific questions, especially due to the large number of cases; for this purpose, further subgroupings should be sought in the data documentation. KEY POINTS: · In Germany, there are currently no guidelines for the endovascular treatment of cerebral vasospasm following spontaneous subarachnoid hemorrhage.. · In addition to oral nimodipine administration endovascular therapy is used to treat cerebral vasospasm in most hospitals.. · This is the first systematic evaluation of nationwide registry data on endovascular treatment of cerebral vasopasm in Germany.. · This real-world data shows that endovascular treatment for cerebral vasospasm has a moderate radiation exposure and can be performed with few complications overall. With (additional) balloon angioplasty, radiation exposure, complication rates and angiographic therapy results are higher or better.. CITATION FORMAT: · Neumann A, Weber W, Küchler J et al. Evaluation of DeGIR registry data on endovascular treatment of cerebral vasospasm in Germany 2018-2021: an overview of the current care situation. Fortschr Röntgenstr 2023; 195: 1018 - 1026.

Radiation Exposure in Interventional Stroke Treatment : Analysis of the German Neurointerventional Database (DeGIR/DGNR) from 2019 to 2021.

PURPOSE: To evaluate patient-related radiation exposure in interventional stroke treatment by analyzing data from the German Society for Interventional Radiology and Minimally Invasive Therapy (DeGIR) and the German Society of Neuroradiology (DGNR) quality registry from 2019-2021. METHODS: The DeGIR/DGNR registry is the largest database of radiological interventions in Germany. Since the introduction of the registry in 2012, the participating hospitals have entered clinical and dose-related data on the procedures performed. To evaluate the current diagnostic reference level (DRL) for mechanical thrombectomy (MT) in stroke patients, we analyzed interventional data from 2019 to 2021 with respect to the reported dose area product (DAP) and factors that might contribute to the radiation dose, such as the localization of the occlusion, technical success using the modified treatment in cerebral ischemia (mTICI) score, number of passages, technical approach, additional intracranial/extracranial stenting, and case volume per center. RESULTS: A total of 41,538 performed MTs from 180 participating hospitals were analyzed. The median DAP for MT was 7337.5 cGy∙cm2 and the corresponding interquartile range (IQR) Q25 = 4064 cGy∙cm2 to Q75 = 12,263 cGy∙cm2. In addition, we discovered that the dose was significantly influenced by occlusion location, number of passages, case volume per center, recanalization score, and additional stenting. CONCLUSION: We conducted a retrospective study on radiation exposure during MT in Germany. Based on the results of more than 41,000 procedures, we observed that the DRL of 14,000 cGy·cm2 is currently appropriate but may be lowered over the next years. Furthermore, we identified several factors that contribute to high radiation exposure. This can aid in detecting the cause of an exceeded DRL and optimize the treatment workflow.

Patterns of acute ischemic stroke and intracranial hemorrhage in patients with COVID-19 : Results of a retrospective multicenter neuroimaging-based study from three central European countries.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is an infection which can affect the central nervous system. In this study, we sought to investigate associations between neuroimaging findings with clinical, demographic, blood and cerebrospinal fluid (CSF) parameters, pre-existing conditions and the severity of acute COVID-19. MATERIALS AND METHODS: Retrospective multicenter data retrieval from 10 university medical centers in Germany, Switzerland and Austria between February 2020 and September 2021. We included patients with COVID-19, acute neurological symptoms and cranial imaging. We collected demographics, neurological symptoms, COVID-19 severity, results of cranial imaging, blood and CSF parameters during the hospital stay. RESULTS: 442 patients could be included. COVID-19 severity was mild in 124 (28.1%) patients (moderate n = 134/30.3%, severe n = 43/9.7%, critical n = 141/31.9%). 220 patients (49.8%) presented with respiratory symptoms, 167 (37.8%) presented with neurological symptoms first. Acute ischemic stroke (AIS) was detected in 70 (15.8%), intracranial hemorrhage (IH) in 48 (10.9%) patients. Typical risk factors were associated with AIS; extracorporeal membrane oxygenation therapy and invasive ventilation with IH. No association was found between the severity of COVID-19 or blood/CSF parameters and the occurrence of AIS or IH. DISCUSSION: AIS was the most common finding on cranial imaging. IH was more prevalent than expected but a less common finding than AIS. Patients with IH had a distinct clinical profile compared to patients with AIS. There was no association between AIS or IH and the severity of COVID-19. A considerable proportion of patients presented with neurological symptoms first. Laboratory parameters have limited value as a screening tool.

Association Between Net Water Uptake and Functional Outcome in Patients With Low ASPECTS Brain Lesions: Results From the I-LAST Study.

BACKGROUND AND OBJECTIVES: The effect of mechanical thrombectomy (MT) on functional outcome in patients with ischemic stroke with low ASPECTS is still uncertain. ASPECTS rating is based on the presence of ischemic hypoattenuation relative to normal; however, the degree of hypoattenuation, which directly reflects net uptake of water, is currently not considered an imaging biomarker in stroke triage. We hypothesized that the effect of thrombectomy on functional outcome in low ASPECTS patients depends on early lesion water uptake. METHODS: For this multicenter observational study, patients with anterior circulation stroke with ASPECTS ≤5 were consecutively analyzed. Net water uptake (NWU) was assessed as a quantitative imaging biomarker in admission CT. The primary end point was the rate of favorable functional outcome defined as modified Rankin Scale score 0-3 at day 90. The effect of recanalization on functional outcome was analyzed according to the degree of NWU within the early infarct lesion. RESULTS: A total of 254 patients were included, of which 148 (58%) underwent MT. The median ASPECTS was 4 (interquartile range [IQR] 3-5), and the median NWU was 11.4% (IQR 8.9%-15.1%). The rate of favorable outcome was 27.6% in patients with low NWU (<11.4%) vs 6.3% in patients with high NWU (≥11.4%; p < 0.0001). In multivariable logistic regression analysis, NWU was an independent predictor of outcome, whereas vessel recanalization (modified thrombolysis in cerebral infarction ≥2b) was only significantly associated with better outcomes if NWU was lower than 12.6%. In inverse-probability weighting analysis, recanalization was associated with 20.7% (p = 0.01) increase in favorable outcome in patients with low NWU compared with 9.1% (p = 0.06) in patients with high NWU. DISCUSSION: Early NWU was independently associated with clinical outcome and might serve as an indicator of futile MT in low ASPECTS patients. NWU could be tested as a tool to select low ASPECTS patients for MT. TRIAL REGISTRATION INFORMATION: The study is registered within the ClinicalTrials.gov Protocol Registration and Results System (NCT04862507).

Detection of Traumatic and Postoperative Nerve Lesions following Upper Extremity Fractures in a Pediatric Cohort Using MR Neurography.

INTRODUCTION: Fractures of the upper extremity are common traumatic injuries in children. Nerve lesions are a rare but typical complication of these fractures. Additional to physical, electrophysiological, and sonographic examinations, magnetic resonance neurography (MRN) can be used to assess the degree and exact localization of nerve damage. This retrospective study was conducted to evaluate the potential role of this examination technique for children and to test a proposed MRN classification of traumatic nerve injury according to Chhabra in a pediatric cohort. MATERIALS AND METHODS: Pediatric patients undergoing MRN for traumatic nerve injury from January 2016 to December 2020 were retrospectively identified. A total of 12 consecutive patients with sufficient clinical data, an MRN, and if available follow-up examination were enrolled and analyzed. RESULTS: In 10 of 12 cases one or more nerve lesions could be identified by MRN using the classification proposed by Chhabra et al. MRN was used to assess nerve injuries, imaging results were compared with clinical course. Clinical follow-up examinations of 10 patients showed an overall good clinical recovery, even in one case with severe trauma and nerve surgery. CONCLUSION: MRN as a noninvasive procedure can help in the evaluation of nerve injury, especially for the identification of lower grade nerve damage and to objectify suspected nerve damage in case of uncertain clinical examination results; thus, can help in decision making whether surgical revision or conservative treatment is preferable.

Computed tomography hypoperfusion-hypodensity mismatch vs. automated perfusion mismatch to identify stroke patients eligible for thrombolysis.

Background and purpose: Automated perfusion imaging can detect stroke patients with unknown time of symptom onset who are eligible for thrombolysis. However, the availability of this technique is limited. We, therefore, established the novel concept of computed tomography (CT) hypoperfusion-hypodensity mismatch, i.e., an ischemic core lesion visible on cerebral perfusion CT without visible hypodensity in the corresponding native cerebral CT. We compared both methods regarding their accuracy in identifying patients suitable for thrombolysis. Methods: In a retrospective analysis of the MissPerfeCT observational cohort study, patients were classified as suitable or not for thrombolysis based on established time window and imaging criteria. We calculated predictive values for hypoperfusion-hypodensity mismatch and automated perfusion imaging to compare accuracy in the identification of patients suitable for thrombolysis. Results: Of 247 patients, 219 (88.7%) were eligible for thrombolysis and 28 (11.3%) were not eligible for thrombolysis. Of 197 patients who were within 4.5 h of symptom onset, 190 (96.4%) were identified by hypoperfusion-hypodensity mismatch and 88 (44.7%) by automated perfusion mismatch (p < 0.001). Of 22 patients who were beyond 4.5 h of symptom onset but were eligible for thrombolysis, 5 patients (22.7%) were identified by hypoperfusion-hypodensity mismatch. Predictive values for the hypoperfusion-hypodensity mismatch vs. automated perfusion mismatch were as follows: sensitivity, 89.0% vs. 50.2%; specificity, 71.4% vs. 100.0%; positive predictive value, 96.1% vs. 100.0%; and negative predictive value, 45.5% vs. 20.4%. Conclusion: The novel method of hypoperfusion-hypodensity mismatch can identify patients suitable for thrombolysis with higher sensitivity and lower specificity than established techniques. Using this simple method might therefore increase the proportion of patients treated with thrombolysis without the use of special automated software.The MissPerfeCT study is a retrospective observational multicenter cohort study and is registered with clinicaltrials.gov (NCT04277728).

Simplified Assessment of Lesion Water Uptake for Identification of Patients within 4.5 Hours of Stroke Onset: An Analysis of the MissPerfeCT Study.

BACKGROUND AND PURPOSE: Many patients with stroke cannot receive intravenous thrombolysis because the time of symptom onset is unknown. We tested whether a simple method of computed tomography (CT)-based quantification of water uptake in the ischemic tissue can identify patients with stroke onset within 4.5 hours. METHODS: This retrospective analysis of the MissPerfeCT study (August 2009 to November 2017) includes consecutive patients with known onset of symptoms from seven tertiary stroke centers. We developed a simplified algorithm based on region of interest (ROI) measurements to quantify water uptake of the ischemic lesion and thereby quantify time of symptom onset within and beyond 4.5 hours. Perfusion CT was used to identify ischemic brain tissue, and its density was measured in non-contrast CT and related to the density of the corresponding area of the contralateral hemisphere to quantify lesion water uptake. RESULTS: Of 263 patients, 204 (77.6%) had CT within 4.5 hours. Water uptake was significantly lower in patients with stroke onset within (6.7%; 95% confidence interval [CI], 6.0% to 7.4%) compared to beyond 4.5 hours (12.7%; 95% CI, 10.7% to 14.7%). The area under the curve for distinguishing these patient groups according to percentage water uptake was 0.744 with an optimal cut-off value of 9.5%. According to this cut-off the positive predictive value was 88.8%, sensitivity was 73.5%, specificity 67.8%, negative predictive value was 42.6%. CONCLUSIONS: Ischemic stroke patients with unknown time of symptom onset can be identified as being within a timeframe of 4.5 hours using a ROI-based method to assess water uptake on admission non-contrast head CT.

Analysis of Angiographic Treatment Response to Intra-Arterial Nimodipine Bolus Injection in Patients with Medically Refractory Cerebral Vasospasm After Spontaneous Subarachnoid Hemorrhage.

BACKGROUND: Intra-arterial nimodipine (IAN) injections are performed in refractory delayed cerebral ischemia (DCI) related to cerebral vasospasm (CVS) after spontaneous subarachnoid hemorrhage (sSAH), but the clinical benefits are inconclusive and angiographic treatment failure is observed. We analyzed angiographic IAN response in a detailed vessel-specific manner and examined the impact of poor angiographic response on the further clinical course. METHODS: Clinical data were retrospectively assessed in patients with spontaneous subarachnoid hemorrhage with symptomatic CVS receiving IAN bolus treatment. Clinical and angiographic predictors for poor angiographic response, DCI-related infarction, and unfavorable outcome were analyzed. RESULTS: Eighty-nine patients were included and 356 treated vessel segments, mainly located in the anterior circulation (93%), were analyzed. Angiographic response was good in 77% of the treated segments. Older age, poor World Federation of Neurosurgical Societies (WFNS) grade 4-5 and early onset of CVS were independently associated with poor angiographic response. The factors short-segment, distal, and bilateral CVS as well as treatment of multiple vessel segments, WFNS grade 4-5, and early onset of CVS were significantly associated with an increased risk of DCI-related infarction. Clinical outcome was significantly influenced by poor WFNS grade and early onset of CVS, whereas poor angiographic response was not related to DCI-related infarction or unfavorable outcome. CONCLUSIONS: The risk of angiographic treatment failure is significantly increased in older patients and those with poor WFNS grade as in cases of early-onset CVS. Although the extent of angiographic CVS significantly affected the development of DCI-related infarction, poor angiographic response had no impact on cerebral infarction and clinical outcome.

The Safety and Effectiveness of the Contour Neurovascular System (Contour) for the Treatment of Bifurcation Aneurysms: The CERUS Study.

BACKGROUND: The Contour is a novel intra-aneurysmal flow disrupting device to treat intracranial aneurysms. OBJECTIVE: To evaluate the safety and effectiveness of the Contour device for treatment of nonruptured intracranial bifurcation aneurysms through a prospective, multicenter, single-arm study. METHODS: Thirty-four patients were enrolled. Primary end points were successful occlusion at 6 mo for efficacy and any major stroke or nonaccidental death up to 30 d or major disabling stroke within 6 mo for safety. Secondary end points were occlusion at 12 mo, retreatment rate, procedure time, and procedure-related/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee. RESULTS: In total, 32 of 34 aneurysms were successfully implanted and, 2 of 34 in the intention-to-treat (ITT) group did not receive the Contour and were excluded from follow-up after 30 d. In addition, 2 of 32 were lost to angiographic follow-up and regarded as treatment failure. The primary safety end point was met in 2 patients in the ITT group. In the perprotocol (PP) group, complete occlusion was seen in 14 of 32 (44%) at 6 mo and 22 of 32 (69%) at 12 mo. Adequate occlusion (Raymond-Roy [RR] 1 and 2) was reached in 84% at a last available follow-up. One patient from the ITT group and 1 from the PP group received additional treatment during follow-up. CONCLUSION: The Contour seems to be both safe and effective in the treatment of intracranial bifurcation aneurysms.

Multi-centric European post-market follow-up study of the Neuroform Atlas Stent System: primary results.

BACKGROUND: Few prospective series have described the safety and effectiveness of the Neuroform Atlas Stent System. We aimed to investigate the efficacy and safety of the device in patients treated for unruptured aneurysm. METHODS: ATLAS EU PMCF is a consecutive, prospective, multicentric study that included patients with unruptured saccular aneurysm of all sizes. Follow-up visits were scheduled at 3-6 months and 12-16 months with digital subtraction angiography (DSA) or MRI imaging follow-up as per the site standard of care. The primary efficacy endpoint was adequate aneurysm occlusion (Raymond Roy occlusion grade I and II) on 12 month angiography. The primary safety endpoint was any major stroke or ipsilateral stroke or neurological death within 12 months. RESULTS: Of the 106 patients consented, 105 were treated with at least one Neuroform Atlas stent. There was a failed implantation attempt in 1 patient, 85 patients received lateral stenting, and 19 patients received Y-stenting. Mean aneurysm neck size was 4.2 mm (range 1.9-33 mm). Adequate occlusion was observed in 95.1% immediately after the procedure and in 98.9% of cases at 1 year DSA follow-up. Overall, 1.0% (1/102; 95% CI 0.0% to 5.3%) of patients experienced a primary safety endpoint of major stroke. Three minor strokes resulted in a modified Rankin Scale score of 2. CONCLUSIONS: In this multicentric, prospective study, stent-assisted coiling of medium size unruptured aneurysms with the Neuroform Atlas stent resulted in a favorable rate of satisfactory occlusion. In our findings, the use of the Y-stenting technique was associated with increased rates of procedural complications. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT02783339.

The "Shiny and Thick High Heel Sign" : A novel radiologic sign for detecting intracranial dural arteriovenous fistulas with time-of-flight magnetic resonance angiography.

PURPOSE: Together with the foramen ovale, the middle meningeal artery (MMA) looks like a high heel shoe print on axial time-of-flight magnetic resonance angiography (TOF-MRA) images, with the MMA resembling the heel. Cranial dural arteriovenous fistulas (DAVF) are often fed by the MMA, which can lead to an increase of signal intensity and diameter of this vessel, resulting in a more "shiny" and "thick" high heel print appearance than on the contralateral side. We describe this finding as a novel radiologic sign and provide cut-off values for the ratios of MMA signal intensities and diameters for predicting the presence of a DAVF. METHODS: A total of 84 TOF-MRA examinations of 44 patients with DAVFs (40 with unilateral MMA feeders, 4 with bilateral feeders) and of 40 patients without DAVFs were included. Diameters and signal intensities of both MMAs were measured by two raters and evaluated using receiver operating characteristic analysis. RESULTS: The diameters of feeding and non-feeding MMAs differed significantly, as did the ratios of signal intensities and of diameters of DAVF and control patients (P < 0.0001). Cut-off values were 1.25 for average signal intensity ratio (shiny high heel sign) and 1.21 for diameter ratio (thick high heel sign). The combination of the "shiny" and the "thick" high heel sign resulted in the highest sensitivity (92.5%) and positive predictive value (95%). CONCLUSION: The described sign seems promising for the detection of DAVFs with noncontrast-enhanced MRI. The TOF-MRA source images should be reviewed with special attention to the MMA.