The risk of cannabis use disorder is mediated by altered brain connectivity: A chronnectome study.

The brain mechanisms underlying the risk of cannabis use disorder (CUD) are poorly understood. Several studies have reported changes in functional connectivity (FC) in CUD, although none have focused on the study of time-varying patterns of FC. To fill this important gap of knowledge, 39 individuals at risk for CUD and 55 controls, stratified by their score on a self-screening questionnaire for cannabis-related problems (CUDIT-R), underwent resting-state functional magnetic resonance imaging. Dynamic functional connectivity (dFNC) was estimated using independent component analysis, sliding-time window correlations, cluster states and meta-state indices of global dynamics and were compared among groups. At-risk individuals stayed longer in a cluster state with higher within and reduced between network dFNC for the subcortical, sensory-motor, visual, cognitive-control and default-mode networks, relative to controls. More globally, at-risk individuals had a greater number of meta-states and transitions between them and a longer state span and total distance between meta-states in the state space. Our findings suggest that the risk of CUD is associated with an increased dynamic fluidity and dynamic range of FC. This may result in altered stability and engagement of the brain networks, which can ultimately translate into altered cortical and subcortical function conveying CUD risk. Identifying these changes in brain function can pave the way for early pharmacological and neurostimulation treatment of CUD, as much as they could facilitate the stratification of high-risk individuals.

CIRSE Standards of Practice on Carotid Artery Stenting.

BACKGROUND: Carotid artery stenting has been used effectively to treat internal carotid artery stenosis since 1989 (Mathias et al. in World J Surg. 25(3):328-34, 2001), with refined and expanded techniques and tools presently delivering outstanding results in percutaneous endoluminal treatment of carotid artery stenosis. PURPOSE: This CIRSE Standards of Practice document is directed at interventional radiologists and details the guidelines for carotid artery stenting, as well as the different implementation techniques. In addition to updating all previously published material on the different clinical indications, it will provide all technical details reflective of European practice for carotid artery stenting. CIRSE Standards of Practice documents do not aim to implement a standard of clinical patient care, but rather to provide a realistic strategy and best practices for the execution of this procedure. METHODS: The writing group, which was established by the CIRSE Standards of Practice Committee, consisted of five clinicians with internationally recognised expertise in carotid artery stenting procedures. The writing group reviewed existing literature on carotid artery stenting procedures, performing a pragmatic evidence search using PubMed to select relevant publications in the English language from 2006 to 2022. RESULTS: Carotid artery stenting has an established role in the management of internal carotid artery stenosis; this Standards of Practice document provides up-to-date recommendations for its safe performance.

Acute bilateral vision loss after endovascular treatment of an intracranial aneurysm.

Acute bilateral vision loss (ABVL) is a rare and challenging diagnostic issue that is most often caused by a neurological disorder. Since it can be the presenting symptom of potentially life-threatening diseases, priority should be given to excluding such diagnoses. Special caution is required if ABVL symptoms result after an intracranial intervention. This article reports on a diagnostic approach for a patient suffering from ABVL due to vitreous hemorrhage related to a subarachnoid hemorrhage (SAH) after endovascular intracranial aneurysm treatment. This case study highlights the importance of imaging interpretation and its consequences.

Evaluation of a novel polymer coil for endovascular occlusion of intracranial aneurysms in a rabbit model.

BACKGROUND AND PURPOSE: The results of the preclinical study of a novel polymer coil in treatment of elastase induced aneurysms will be presented in this paper. MATERIAL AND METHODS: We induced 16 aneurysms in 16 New Zealand white rabbits at the origin of the right common carotid artery at the brachiocephalic trunk. Newly developed polymer coils in both groups for six aneurysms each and platinum coils for two aneurysms each were used. Control angiographies followed in both groups immediately after coiling as well as in the first eight animals 30 days after intervention (30 days group) and in the other eight animals 90 days after (90 days group). An explanation and histological evaluation of the treated aneurysms followed. RESULTS: The 12 animals in which the aneurysms were treated with polymer coils showed a complete occlusion (grade IV) in only 6 out of 12 aneurysms (50%), an almost complete occlusion (grade III) in 5 out of 12 (42%) and an incomplete occlusion in the treatment of one aneurysm (8%). Histologically, we observed a significantly more pronounced inflammatory response and neoangiogenesis in aneurysms treated with polymer coils only in the 30 days group. CONCLUSION: Most difficulties and concerns with the polymer coils were related to the flexibility and detachment behaviour. Therefore, and due to the technical challenges of delivery, the novel polymer coil cannot be considered an alternative to the current platinum coils.

Development and Evaluation of an MRI Artifact-Free Aneurysm Clip.

BACKGROUND AND OBJECTIVES: The digital subtraction angiography is still the gold standard in the follow-up after aneurysm surgery, although it remains a repeating invasive technique with accumulating X-ray exposure. An alternative magnetic resonance angiography has the disadvantage of metal-related artifacts. A metal-free aneurysm clip could overcome this problem. Recent advances in manufacturing technologies of fiber-reinforced plastics might allow developing a prototype of a metal-free clip. METHODS: The prototype was formed out of carbon fiber-reinforced polyetheretherketone (CF-PEEK) in accordance with the standard clip design. In vivo and in vitro studies were performed to analyze the central nervous system biocompatibility. The prototype was tested in a phantom in a 3 T MRI scanner and microtomography scanner. For in vivo assessment, the left renal artery of rats was either ligated with a suture, clipped with a regular titanium clip or with the CF-PEEK prototype clip. The animals underwent standard MRI sequences and magnetic resonance angiography and assessment by a blinded neuroradiologist. RESULTS: Phantom studies showed no signs of artifacts. The prototype showed a reliable clamping and reopening after clip application, although the clamping force was reduced. In vivo studies showed a successful occlusion of the renal artery in all cases in the magnetic resonance angiography. Clip artifacts were statistically significant reduced in the prototype group (P < .01). CF-PEEK showed no signs of impaired biocompatibility compared with the titanium samples in vitro and in vivo. CONCLUSION: Former attempts of metal-free aneurysm clips did not meet the criteria of the standard clip design. In this study, the practicability of this new CF-PEEK artifact-free aneurysm clip has been proven. The further fabrication developments should overcome the problem of a reduced clamping force in the future. After clinical approval, it will improve the magnetic resonance image quality and might help to reduce the amount of digital subtraction angiography in the follow-up.

Extracranial internal carotid aneurysm treated with a covered stent in an infant.

BACKGROUND: Extracranial internal carotid aneurysms consist a rare pathology with an overall incidence less than 1% in the general population, and warrant treatment due to their association with cerebrovascular events and neurological complications. The incidence is even lower in the pediatric population. CASE REPORT: A 14-month infant presented in our clinic with neck swelling of unknown origin, with subsequent MR imaging revealing an extracranial internal carotid aneurysm. Due to the patient's age and risk of surgical complications, the decision to proceed with endovascular repair with stent placement and complete exclusion of the aneurysm from the circulation was made, after multidisciplinary consultation. RESULTS: In the pediatric population, pediatric population, endovascular stent placement can be considered at least as a last resort treatment when surgical access harbors significant risks or is impossible.

Impact of cannabis use on brain metabolism using 31P and 1H magnetic resonance spectroscopy.

PURPOSE: This prospective cross-sectional study investigated the influence of regular cannabis use on brain metabolism in young cannabis users by using combined proton and phosphorus magnetic resonance spectroscopy. METHODS: The study was performed in 45 young cannabis users aged 18-30, who had been using cannabis on a regular basis over a period of at least 2 years and in 47 age-matched controls. We acquired 31P MRS data in different brain regions at 3T with a double-resonant 1H/31P head coil, anatomic images, and 1H MRS data with a standard 20-channel 1H head coil. Absolute concentration values of proton metabolites were obtained via calibration from tissue water as an internal reference, whereas a standard solution of 75 mmol/l KH2PO4 was used as an external reference for the calibration of phosphorus signals. RESULTS: We found an overall but not statistically significant lower concentration level of several proton and phosphorus metabolites in cannabis users compared to non-users. In particular, energy-related phosphates such as adenosine triphosphate (ATP) and inorganic phosphate (Pi) were reduced in all regions under investigation. Phosphocreatine (PCr) showed lowered values mainly in the left basal ganglia and the left frontal white matter. CONCLUSION: The results suggest that the increased risk of functional brain disorders observed in long-term cannabis users could be caused by an impairment of the energy metabolism of the brain, but this needs to be verified in future studies.

[Secondary tumors following radiation therapy and chemotherapy : Incidence of cavernous hemangiomas]. / Zweittumoren nach Bestrahlung und Chemotherapie : Auftreten von Kavernomen.

PROBLEM: There is a risk of developing secondary central nervous system (CNS) tumors after cranial radiation therapy. Meningiomas and pituitary tumors are also increasingly treated with radiation therapy, which means that the risk of secondary tumors from radiation in children and adults must be communicated. METHODS: Studies in children show that radiation causes a 7- to 10-fold increase in subsequent CNS tumors with a cumulative incidence over 20 years ranging from 1.03 to 28.9. The latency period for the occurrence of secondary tumors ranged from 5.5 to 30 years, with gliomas developing after 5-10 years and meningiomas around 15 years after irradiation. The latency period for secondary CNS tumors in adults ranged from 5 to 34 years. CONCLUSION: After radiation treatment, tumors can rarely occur as secondary sequelae, mostly meningiomas and gliomas, but also cavernomas. The treatment and long-term results of radiation-induced CNS tumors showed no worse results than primary CNS tumors over the course of time.

Recurrent reversible in-stent-stenosis after flow diverter treatment.

Flow diverter stents (FDS) are well established in the treatment of intracranial aneurysms which are difficult to treat with conventional endovascular techniques. However, they carry a relatively high risk of specific complications compared to conventional stents. A minor but frequent finding is the occurrence of reversible in-stent-stenosis (ISS) that tend to resolve spontaneously over time. Here, we report the case of a patient in their 30s who was treated with FDS for bilateral paraophthalmic internal carotid artery (ICA) aneurysms. ISS were found at the respective early follow-up examinations on both sides and had resolved at the 1-year follow-up examinations. Surprisingly ISS reoccurred at both sides in later follow-up examinations and again resolved spontaneously. The recurrence of ISS after resolution is a finding that has not been described previously. Its incidence and further development should be investigated systematically. This might contribute to our understanding of the mechanisms underlying the effect of FDS.

Functional correlates of neurological soft signs in heavy cannabis users.

Sensorimotor dysfunction has been previously reported in persons with cannabis dependence. Such individuals can exhibit increased levels of neurological soft signs (NSS), particularly involving motor coordination, sensorimotor integration and complex motor task performance. Abnormal NSS levels can also be detected in non-dependent individuals with heavy cannabis use (HCU), yet very little is known about the functional correlates underlying such deficits. Here, we used resting-state functional magnetic resonance imaging (MRI) to investigate associations between NSS and intrinsic neural activity (INA) in HCU (n = 21) and controls (n = 26). Compared with controls, individuals with HCU showed significantly higher NSS across all investigated subdomains. Three of these subdomains, that is, motor coordination, sensorimotor integration and complex motor task behaviour, were associated with specific use-dependent variables, particularly age of onset of cannabis use and current cannabis use. Between-group comparisons of INA revealed lower regional homogeneity (ReHo) in left precentral gyrus, left inferior occipital gyrus, right triangular pat of the inferior frontal gyrus and right precentral gyrus in HCU compared with controls. In addition, HCU showed also higher ReHo in right cerebellum and left postcentral gyrus compared with controls. Complex motor task behaviour in HCU was significantly related to INA in postcentral, inferior frontal and occipital cortices. Our findings indicate abnormal ReHo in HCU in regions associated with sensorimotor, executive control and visuomotor-integration processes. Importantly, we show associations between ReHo, cannabis-use behaviour and execution of complex motor tasks. Given convergent findings in manifest psychotic disorders, this study suggests an HCU endophenotype that may present with a cumulative risk for psychosis.

Endovascular Treatment Strategies for Aneurysms of the Origin of the Posterior Inferior Cerebellar Artery.

BACKGROUND: Treatment of aneurysms at the origin of the posterior inferior cerebellar artery (PICA) is challenging. Surgery is difficult due to the deep location and proximity to cranial nerves and endovascular treatment is complicated due to the often tortuous anatomy of the PICA and its small diameter. The purpose of this study is to report our experience with the endovascular treatment of aneurysms at the origin of the PICA. METHODS: Consecutive patients with aneurysms at the origin of the PICA who were endovascularly treated at our department were identified from our registry of neuro-angiographies. Clinical, angiographic, and treatment data were analyzed. Endpoints included successful occlusion and recurrence. RESULTS: Twenty-nine patients were included. 79.3% of the aneurysms were wide-neck with a dome-to-neck ratio <2.65.5% of all endovascular procedures were performed by coiling alone. The procedural rupture rate was 18.75% for endovascularly treated aneurysms presenting with subarachnoid hemorrhage (SAH). Successful embolization was achieved non-significantly more often in the coiling-only group (94.7% vs. 70%, P = 0.066). Aneurysm recurrence after successful occlusion was observed in one case. CONCLUSIONS: Though aneurysm and parent vessel characteristics were challenging successful occlusion was achieved in a high rate of treatments, often with standalone coiling. Adjunctive techniques like retrograde stenting seem promising to further enhance endovascular results. Interestingly aneurysms arising solely from the origin of the PICA without the V4-segment involved presented with SAH significantly more often and wide-neck aneurysms presenting with SAH had a significantly higher periinterventional rupture rate.

[Interdisciplinary neurovascular conference-opportunities and benefits]. / Interdisziplinäre Neurovaskuläre Konferenz ­ Chancen und Nutzen.

CLINICAL/METHODOLOGICAL ISSUE: The neurovascular conference is a discussion platform for the fields of neurology, neurosurgery, vascular surgery and neuroradiology. METHODOLOGICAL INNOVATIONS: Interdisciplinary exchange allows creation of individual treatment concepts for elective patients with neurovascular diseases regarding further measures for prevention, treatment and aftercare. ACHIEVEMENTS: Establishment of individual treatment concepts for patients with neurovascular diseases regarding treatment recommendations based on current guidelines, scientific evidence and treatment standards based on them. PERFORMANCE: Elective patients with neurovascular diseases.

Treatment of Wide-Necked Cerebral Aneurysms Using the WEB Device Including Flow Alteration Assessment With Color-Coded Imaging: A Single Center Experience.

Objective: The Woven EndoBridge (WEB) device (MicroVention, Tustin, CA) has extended the treatment of cerebral aneurysms. Despite the fact that the WEB device has shown promising clinical results, little is known about the caused intra-aneurysmal flow alterations. Here we present our clinical experience with the WEB, including examining various syngo iFlow (Siemens AG, Erlangen, Germany) parameters to predict aneurysm occlusion. Methods: We reviewed the data from patients with unruptured cerebral aneurysms treated with a WEB device between 2016 and 2020. Aneurysm occlusion and complications were assessed. Furthermore, different quantitative criteria were evaluated using syngo iFlow after digital subtraction angiography. Results: A total of 26 patients hosting 26 cerebral aneurysms met the inclusion criteria. Follow-up was available for 21 patients, with a mean of 7.3 ± 6.3 months. A total of 71.4% (n = 15) of the aneurysms included were located in the anterior and 28.6% (n = 6) in the posterior circulation. Adequate aneurysm occlusion was achieved in 85.7% (n = 18). The iFlow parameters for reduced aneurysm outflow (ID-R) differed significantly from the parameters for reduced inflow (PI-R and PI-D) (P < 0.001). The parameters did not differ significantly between adequately and insufficiently occluded aneurysms. Only a trend towards a lower ID-R of insufficiently occluded aneurysms was observed (P = 0.063), indicating a potential predictive value for insufficient aneurysmal outflow. There was no treatment-related morbidity or mortality. Conclusions: The applied syngo iFlow parameters confirmed that flow changes induced by the WEB device significantly affect outflow compared to inflow and have potential predictive value for adequate aneurysm occlusion.

Endovascular treatment of unruptured intracranial aneurysms with flow diverters: A retrospective long-term single center analysis.

PURPOSE: The introduction of flow diverters (FDs) in 2007 greatly enhanced the treatment of intracranial aneurysms. Here, we present our long-term clinical experience in treating unruptured intracranial aneurysms with FDs. METHODS: 107 patients with unruptured aneurysms and treated with an FD between 2010 and 2019 were retrospectively reviewed. Aneurysm occlusion, procedural complications, and clinical outcome were evaluated. RESULTS: Angiographic follow-up was available for 93 patients with a mean long-term follow-up time of 28.4 ± 21.6 months. Additional coiling was performed in 15.1% of patients (n = 14). Adequate aneurysm occlusion (Kamran grades 3 and 4) at long-term follow-up was achieved in 94.6% of patients (n = 88). 3.2% (n = 3) required endovascular retreatment since the last follow-up showed a lack of aneurysm occlusion (Kamran grade 0) due to a foreshortening of the FD. Incomplete opening of the FD and parent vessel occlusion was seen in 1.1% (n = 1) and 3.2% (n = 3) of patients, respectively. In-stent stenosis was observed in 57% (n = 53) of cases at short-term follow-up and 22.6% (n = 21) at long-term, which were moderate and asymptomatic overall. In-stent stenosis decreased significantly between short- and long-term follow-ups (31.4 ± 17.0% vs 9.7 ± 13.6%, respectively; p ≤ 0.001). Thromboembolic and hemorrhagic events occurred in 7.5% (n = 7) and 1.1% (n = 1) of patients, respectively. Good clinical outcome (modified Rankin scale: 0-2) was obtained in 97.8% (n = 91) leading to an overall treatment-related morbidity of 2.2% (n = 2). There was no procedural mortality. CONCLUSION: Our study shows that FD treatment of unruptured intracranial aneurysms is effective and safe with high occlusion rates and low rates of permanent morbidity at long-term follow-up.

Transorbital embolization of cavernous sinus dural arterio-venous malformations with surgical exposure and catheterization of the superior ophthalmic vein.

PURPOSE: Cavernous sinus dural arterio-venous malformations (dAVF) represent a pathologic connection between branches of the internal and/or external carotid artery and the cavernous sinus. Standard endovascular approaches for dAVF treatment are transvenous embolization through the inferior petrosal sinus or the facial vein and transarterial embolization. These approaches are not always successful or feasible, and alternative techniques are required. Here, we present a case series of a minimally invasive transorbital approach with surgical exposure and catheterization of the superior ophthalmic vein for transvenous fistula coiling. METHODS: 14 patients with dAVFs (Barrow Type B to D) that were treated at a tertiary care medical center over a period of 13 years were included in the study. Patients with persisting dAVF associated symptoms were selected for this approach when conventional endovascular interventions were not successful or not feasible. The surgical procedure was performed under general anaesthesia. RESULTS: A successful transorbital approach was performed in all 14 cases. In 12 of 14 patients a catheter assisted successful embolization of the fistula was performed using platinum coils with no relevant residual fistula flow. In two cases, a spontaneous thrombosis of the fistula during the surgical procedure required no further embolization. No postoperative therapy-associated complications were observed. CONCLUSION: The described approach is an effective method to embolize dAVFs in selected cases when catheter assisted transvenous and/or transarterial embolization is not successful or not feasible. In this case series we demonstrate an excellent success rate with no therapy-associated major complications.

Cranial MRI in Childhood Acute Leukemia during Treatment and Follow-Up Including the Impact of Intrathecal MTX-A Single-Center Study and Review of the Literature.

Due to high survival rates, long-term sequelae, especially neurotoxicity, need to be considered in childhood acute leukemias. In this retrospective analysis of morphologic changes of the brain in children treated for acute leukemias, we included 94 patients (77 ALL, 17 AML; 51 male, 43 female; median age: 5 years) from a single center. We analyzed 170 cranial MRI scans (T2, FLAIR axial) for morphologic alterations of the brain and variations of the ventricular width (GDAH). In addition, the corresponding literature was reviewed. More than 50% of all patients showed cerebral pathomorphologies (CP). They were seen more often in children with ALL (55.8%), ≤ 6 years of age (60.8%), in relapse (58.8%) or after CNS irradiation (75.0%) and included white matter changes, brain atrophy, sinus vein thrombosis and ischemic events. GDAH significantly enlarged mainly in children up to 6 years, with relapse, high-risk leukemias or ALL patients. However, GDAH can normalize again. The number of intrathecal Methotrexate applications (≤12 vs. >12) showed no correlation to morphologic alterations besides a significant increase in GDAH (−0.3 vs. 0.9 mm) between the first and last follow-up MRI in ALL patients receiving >12 ith. MTX applications. The role of ith. MTX on CP needs to be further investigated and correlated to the neurocognitive outcome of children with acute leukemias.

Schwannoma of the Hypoglossal Nerve Mimicking Carotid Body Paraganglioma.

Carotid body paragangliomas (CBPs) clinically present as highly vascularized cervical masses with a pathognomonic localization at the carotid artery bifurcation. Following ultrasonography and MRI/CT imaging, surgical resection with optional preoperative embolization is considered as the treatment of choice in most cases. We herein present the case of a 60-year-old female with characteristic clinical signs and imaging findings of a right-sided CBP who finally went to surgical treatment. Intraoperatively, the tumor showed an adherent growth to the hypoglossal nerve that had to be partially resected, resulting in a postoperative nerve palsy. Histological examination of the resected tumor revealed the unexpected diagnosis of a hypoglossal nerve schwannoma. To the best of our knowledge, we herein present the third case reported in the literature of a unilateral hypoglossal schwannoma located at the carotid bifurcation mimicking clinical symptoms, imaging and intraoperative findings of a CBP.

Long-term follow-up MRI shows no hastening of adjacent segment degeneration following cervical disc arthroplasty.

Cervical disc arthroplasty is an established procedure, but studies with data on long-term clinical outcome, reoperation for symptomatic adjacent segment degeneration (sASD), and degenerative changes based on MRI findings are rare. Thus, a file review was performed and patients with complete documentation of neurological status at preoperative, postoperative, 12 month, 3-4 years follow-up including surgical reports for reoperation with a minimum follow-up of 9 years were included. Final follow-up assessment included a physical examination, assessment of pain levels, Odoms criteria, Neck disability index. The degeneration of each cervical segment at preoperative and at final follow-up was assessed using an MRI. Forty-six out of 68 included patients participated, the mean follow-up was 11 (range 9-15) years, at which 71.7% of patients were free of arm pain, 52.2% of patients were free of neck pain, 63% of patients had no sensory dysfunction, and full motor strength was noted in 95.6% of patients. The clinical success rate was 76.1%, the mean NDI was 12%. Overall repeated procedure rate was 17%, the reoperation rate for sASD was 9%, and removal of CDA was performed in 4%. MRI showed progressive degeneration but no significant changes of SDI from preoperative to final follow-up.