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Purpose: Pilomyxoid astrocytomas (PMA) are pediatric brain tumors predominantly located in the suprasellar region, third ventricle and posterior fossa, which are considered to be more clinically aggressive than pilocytic astrocytomas (PA). Another entity, intermediate pilomyxoid tumors (IPT), exists within the spectrum of pilocytic/pilomyxoid astrocytomas. The 2021 WHO CNS classification refrained from assigning grade 1 or 2 status to PMA, thereby reflecting the need to further elucidate their clinical and imaging characteristics., Methods: We included a total of 15 patients with PMA, IPT and suprasellar PA. We retrospectively evaluated immunohistochemistry, imaging findings and diffusion characteristics within these tumors as well as whole exome sequencing for three of the cases., Results: 87% of the tumors were supratentorial with 11 cases suprasellar in location, 1 case located in the frontal white matter and 1 in the hippocampus. 6 cases demonstrated intraventricular extension. ADC values were higher in PMA and IPT than PA. 3 cases demonstrated KIAA1549-BRAF-fusion, 2 had BRAF[Formula: see text]-mutation and 6 were BRAF-wildtype. All cases had recurrence/progression on follow-up., Conclusion: PMA and IPT do not demonstrate aggressive imaging characteristics in respect to their diffusion imaging with ADC values being higher than PA. Lack of BRAF-alteration in PMA corresponded to atypical location of tumors with atypical driver mutations and mechanisms., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: The distance to thrombus (DT) on CT angiography was recently proposed as a predictor of outcome in patients treated by intravenous thrombolysis (IVT) for stroke due to occlusion of the middle cerebral artery (MCA). The purpose of the present study was to validate its inter-rater reliability and its prognostic value on contrast-enhanced magnetic resonance angiography (CE-MRA). Furthermore, we investigated the relation between DT and FLAIR-vascular hyperintensities (FVH) as a surrogate of collateral circulation and hypoperfusion., Methods: Patients with acute MCA occlusions treated by IVT and diagnosed with magnetic resonance imaging (MRI) were included. Two readers measured DT. FVH and acute DWI lesion volumes were quantified. Clinical status was determined using the initial NIH stroke scale (NIHSS) and 90-day modified Rankin Scale (90d mRS)., Results: Sixty-one patients showed a lesion on diffusion-weighted magnetic resonance images and an occlusion of the MCA on CE-MRA. We found significant inverse correlations between DT and NIHSS scores at admission (ρ = -0.29; P = 0.02), DT and mRS at 90 days (ρ = -0.29; P = 0.04), and between DT and FVH (ρ = -0.32; P = 0.01). For a DT <22 mm, the likelihood of an unfavorable outcome (90d mRS 3-6 or NIHSS score improvement of ≤10 points at discharge) was >50 %. Initial DWI lesion volumes showed no correlation with the outcome. Excellent inter-rater agreement for DT was observed (Cronbach's α = 0.98; P < 0.001)., Conclusions: DT on CE-MRA is reliably measurable, correlates inversely with FLAIR-vascular hyperintensities, and predicts outcome in patients with acute MCA occlusion treated with IVT.

Introduction: The purpose of this study is to investigate the efficacy and safety of mechanical thrombectomy in patients with acute vertebrobasilar artery occlusion (VBAO) using the Trevo Stentriever™ device., Methods: Twenty patients diagnosed with VBAO underwent digital subtraction angiography (DSA) with the intention to perform mechanical thrombectomy with stent-retrievers between August 2011 and October 2013. Two patients were excluded because another device was primarily used; in two other patients, thrombectomy was not possible., Results: Thrombectomy with the Trevo device was performed in 16 patients. The Stentriever™ was used either as the sole device (56.3 %) or in conjunction with up to four additional devices or techniques. Thirty-three clot retrieval manoeuvres were performed (mean 2.1 ± 1.3, range 1-5); the device could be deployed and retrieved in all manoeuvres (100 %). No device-related complications occurred. Mean duration of the endovascular intervention was 71.8 min (±39.9; range 22-144). Complete or near complete recanalization (thrombolysis in cerebral infarction (TICI) ≥2b) was achieved in 13 patients (81.3 %). Eleven patients (68.8 %) survived and seven patients (43.8 %) showed a good clinical outcome at discharge, defined as modified Rankin Scale (mRS) 0-2 or National Institute of Health Stroke Scale (NIHSS) improvement ≥10 points. Including the two patients in whom thrombectomy was not possible, successful recanalization, good clinical outcome and survival were achieved in 72.2, 38.9 and 61.1 %, respectively., Conclusions: Thrombectomy in patients with acute VBAO using the Trevo Stentriever™-either as the sole device or in conjunction with other devices-is feasible and seems to be similarly effective and safe as in the anterior circulation compared to reported data in the literature.

Background: Despite new methods for treating complete stenosis of the nasolacrimal duct dacryocystorhinostomy remains the standard operation. Implanting a nasolacrimal polyurethane stent through the nasolacrimal duct to preserve the natural lacrimal pathway seems to offer alternative procedure with similar success rate and without skin incision and general anesthesia. We examined whether an anatomically correct position increases its success rates., Methods: This prospective study included 40 patients (mean age 57 years). The polyurethane stent was implanted during dacryocystography, and its position was checked at follow-up visits after 6 months. In the event of an additional canalicular stenosis a 45-mm-long stent was implanted, in the other patients a 35-mm-long stent., Results: A dacryocystographically correct position was found in only 21 of 40 patients; in the other 19 the stent did not enter the nose under the inferior concha. However, there was no correlation between correct position under the inferior concha and success rate. In 8 of the 40 patients the stent was not patent., Conclusion: The postoperative success rate cannot be predicted by the radiographic position along the ductus nasolacrimalis.

We report hemimegalencephaly in a 44-year-old woman with mental retardation, epilepsy and a mild hemiparesis. In addition to typical findings on MRI, 2-deoxy-2[18F]fluorodeoxyglucose positron-emission tomography (PET) demonstrated glucose hypometabolism of the affected hemisphere. The results of PET have been coregistered with morphological information from the MRI studies by image fusion.

Unlabelled: Dacryocystorhinostomy is still the standard procedure complete stenosis of the nasolacrimal duct. New methods try to preserve the natural lacrimal pathway. Song implanted in 1995 a nasolacrimal polyurethane stent through the nasolacrimal duct. The results and complications of this new method are described in this prospective study., Methods: Thirty consecutive patients with complete obstruction of the nasolacrimal duct or lacrimal sac were included in the study. The stenosis was localized by dacryocystography. The ages ranged from 22 to 87 years (mean, 58.9 +/- 16 years). Dacryocystography was performed immediately, 4 weeks and 8 months after the procedure to verify the position and patency of the stent., Results: Twenty-five short (35 mm) and 5 long (45 mm) stents were implanted. Twenty-four of 30 patients after 4 weeks and 9 of 10 patients after 8 months had reduced or no complaints. In 1 patient the stent was obstructed. Forceful irrigation with saline solution permitted recanalization. In 1 patient the stent had moved into the upper canaliculus. Because of irritation of the canaliculus it had to be pulled out after 2 months., Conclusion: The follow-up is still too short to recommend stent implantation as a real alternative to dacryocystorhinostomy. The main advantages are that the procedure is faster, no incision is necessary, and the local anesthesia is easier. The disadvantage is the need for X-ray examination.

We assessed high-resolution MRI of the lacrimal system with conjunctival contrast enhancement in patients with suspected stenosis. We studied 18 patients with epiphora affecting 22 eyes, using a surface coil, before and after conjunctival and intravenous Gd-DTPA. Stenosis or obstruction of the ducts was found in 18 of 22 cases: at canalicular level in 3 cases, at the sac in 7 cases, and in the nasolacrimal duct in 8 cases. Periductal pathology following surgery to the maxillary sinus or dacryocystorhinostomy was seen in three cases. In conjunction with the findings on syringing and/or conventional dacryocystography, the narrowing was classified as stenosis or obstruction.

Unlabelled: Both dacryocystography and dacryoscintigraphy are well established in the evaluation of stenoses of the lacrimal drainage system. They provide limited information about the ductal anatomy itself and about periductal structures. MR imaging was evaluated for its capability to directly visualize the lacrimal drainage system in detail and simultaneously provide functional characterization of dacryostenosis., Subjects and Methods: Twenty-seven lacrimal drainage systems of 23 patients suffering from epiphora were examined in an MR unit before and after conjunctival and intravenous application of Gd-DTPA using a surface coil., Results: Dacryostenosis was found in 23 of 27 lacrimal systems. Stenoses were localized to the canalicular (n = 3), saccular (n = 8), and ductal (n = 12) level, and were classified as stenosis or occlusion., Conclusion: MR imaging with conjunctival contrast application allows within one examination both detailed morphological and functional assessment of the lacrimal drainage system with depiction of surrounding structures. Limitations arise mainly from demands on technical and patient-related preconditions.

Cranial and cervical vessels are rarely involved in neurofibromatosis type 1. Stenoses and occlusion due to intimal or medial dysplasia are most often seen, followed by aneurysms. We report a rare asymptomatic giant aneurysm of the vertebral artery in a 59-year old man with von Recklinghausen's neurofibromatosis and review the literature.