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Background and Purpose: Assessing the treatment success of intracranial aneurysms treated with Woven EndoBridge (WEB) devices using MRI is important in follow-up imaging. Depicting both the device configuration as well as reperfusion is challenging due to susceptibility artifacts. We evaluated the usefulness of the contrast-enhanced 3D ultrashort TE (UTE) sequence in this setting., Materials and Methods: In this prospective study, 12 patients (9 women) with 15 treated aneurysms were included. These 12 patients underwent 18 MRI examinations. Follow-up UTE-MRI controls were performed on the same 3T scanner. We compared the visualization of device configuration, artifact-related virtual stenosis of the parent vessel, and the WEB occlusion scale in 3D isotropic UTE-MRI postcontrast with standard TOF-MRA with contrast-enhancement (CE) and without IV contrast as well as DSA. Two interventional neuroradiologists rated the images separately and in consensus., Results: Visualization of the WEB device position and configuration was rated superior or highly superior using the UTE sequence in 17/18 MRIs compared with TOF-MRA. Artifact-related virtual stenosis of the parent vessel was significantly lower in UTE-MRI compared with TOF and CE-TOF. Reperfusion was visible in 8/18 controls on DSA. TOF was able to grade reperfusion correctly in 16 cases; CE-TOF, in 16 cases; and UTE, in 17 cases., Conclusions: Contrast-enhanced UTE is a novel MRI sequence that shows benefit compared with the standard sequences in noninvasive and radiation-free follow-up imaging of intracranial aneurysms treated using the WEB device., (© 2025 by American Journal of Neuroradiology.)

Objective: Our study aimed to investigate potential alterations in iron deposition within pulvinar, using susceptibility weighted imaging (SWI) MRI in epilepsy patients through a biomarker termed the "hypointense pulvinar sign.", Methods: A full-text radiological information system search of radiological reports was performed for the term "epilepsy" between 2014 and 2022. Only patients with the diagnosis of epilepsy were included. SWI was assessed by two readers recording lateralization of an asymmetrically more hypointense pulvinar. Cohen's kappa for inter-rater reliability was calculated. Fisher's exact test was performed to assess for significance between groups., Results: Our epilepsy cohort comprised 105 patients with following diagnoses: 45 intra-axial tumor, 13 meningioma, 13 MRI negative, 12 encephalomalacia, seven siderosis, six cavernoma, five arteriovenous malformation, two acute demyelinating encephalomyelitis, one tuberous sclerosis, one giant aneurysm. The hypointense pulvinar sign was correct in 44% of cases. Notably, right hemispheric lesions exhibited a significantly higher proportion of correct hypointense pulvinar signs compared to the left hemisphere (46% vs 24%; p = 0.044). Inter-rater reliability was substantial at 0.62 ( p < 0.001). Only two of 21 (10%) of healthy controls demonstrated a hypointense pulvinar sign, which was significantly different from the epilepsy cohort ( p < 0.01)., Conclusions: The hypointense pulvinar sign has proven to be a reproducible, simple to use biomarker for iron deposition in epilepsy which could be considered for inclusion into multimodal precision medicine models., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Introduction: Magnetic resonance imaging (MRI) is both a crucial clinical and research tool for patients with deep brain stimulation (DBS) devices. However, safety concerns predominantly related to device heating have limited such imaging. Rigorous safety testing has demonstrated that scanning outside of vendor guidelines may be both safe and feasible, unlocking unique opportunities for advanced imaging in this patient population. Currently, however, 3T MRI safety data including advanced MRI sequences in novel directional and sensing DBS devices is lacking., Methods: An anthropomorphic phantom replicating bilateral DBS system was used to assess the temperature rise at the electrode tips, implantable pulse generator, and cranial loop during acquisition of routine clinical sequences (three dimensional [3D] T1, GRE T2*, T2 FSE) and advanced imaging sequences including functional MRI (fMRI), arterial spin labelling (ASL), and diffusion weighted imaging (DWI). Measures of radiofrequency exposure (specific absorption rate [SAR] and root-mean square value of the MRI effective component of the radiofrequency transmission field [B1+rms]) were also recorded as an indirect measure of heating. Testing involved both a new directional and sensing DBS device (Medtronic: B30015 leads and Percept PC neurostimulator) and a previous-generation DBS device (Medtronic: 3,387 leads and Percept PC neurostimulator) in combination with a state-of-the-art (Siemens MAGNETOM Prisma) and a previous-generation (GE Signa HDxt) 3T MRI scanner., Results: On the state-of-the-art 3T MRI scanner, the new DBS device produced safe temperature rises with clinically used sequences and fMRI but not with other advanced sequences such as DWI and ASL, which also exceeded B1+rms vendor guidelines (i.e., ≤2 μT). When scanned on the previous MRI scanner, the recent DBS device produced overall lower and slower temperature rises compared to the previous DBS model. Among the sequences performed on this scanner, several (3D T1, DWI, T2 FSE, and ASL) exceeded the approved SAR vendor limit (<1 W/kg), but only ASL resulted in an unacceptable temperature rise during scanning of the previous DBS model., Conclusion: These phantom safety data show that both clinically used MRI sequences and research sequences such as fMRI can be successfully acquired on 3T MRI scanners with a novel directional and sensing DBS model. As several of these sequences were obtained outside regulatory-approved vendor guidelines, preemptive safety testing should be done. As directional leads become increasingly common, improving MRI safety knowledge is crucial to expand clinical and research possibilities., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

Background: The patency of intracranial stents may not be reliably assessed with either CT angiography or MR angiography due to imaging artifacts. We investigated the potential of ultra-high resolution CT angiography using a photon counting detector (PCD) CT to address this limitation by optimizing scanning and reconstruction parameters., Methods: A phantom with different flow diverters was used to optimize PCD-CT reconstruction parameters, followed by imaging of 14 patients with intracranial stents using PCD-CT. Images were reconstructed using three kernels based on the phantom results (Hv56, Hv64, and Hv72; Hv=head vascular) and one kernel to virtually match the resolution of standard CT angiography (Hv40). Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements were calculated. Subjective image quality and diagnostic confidence (DC) were assessed using a five point visual grading scale (5=best, 1=worst) and a three point grading scale (1=best, 3=worst), respectively, by two independent neuroradiologists., Results: Phantom images demonstrated the highest image quality across dose levels for 0.2 mm reconstructions with Hv56 (4.5), Hv64 (5), and Hv72 (5). In patient images, SNR and CNR decreased significantly with increasing kernel sharpness compared with control parameters. All reconstructions showed significantly higher image quality and DC compared with the control reconstruction with Hv40 kernel (P<0.001), with both image quality and DC being highest with Hv64 (0.2 mm) and Hv72 (0.2 mm) reconstructions., Conclusion: Ultra-high resolution PDC-CT angiography provides excellent visualization of intracranial stents, with optimal reconstructions using the Hv64 and the Hv72 kernels at 0.2 mm., Registration: BASEC 2021-00343., Competing Interests: Competing interests: TF is an employee of Siemens Healthcare. HA has received institutional grants from Bayer, Canon, Guerbet, and Siemens. HA received speaker honoraria from Siemens., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: The impact of therapeutic embolization as a stand-alone treatment of head and neck paragangliomas considered surgically high-risk remains insufficiently understood. The aim of this study was to investigate the procedural risks and long-term volumetric development in head and neck paragangliomas with high surgical risk following therapeutic endovascular embolization as a stand-alone treatment., Materials and Methods: A retrospective database review of patients who underwent endovascular embolization as primary treatment for head and neck paragangliomas lacking appropriate curative treatment options at our institution (from January 2000 to February 2023) was conducted. Tumor volumetric analyses were performed before embolization and during follow-up. To assess the changes in tumor volume over time, the measurements were performed after embolization, first at 6 months and then on a yearly basis up to 6 years (mean follow-up time was 33.7 ± 24.4 months). Subgroup analyses were conducted for vagal and jugular/jugulotympanic paragangliomas., Results: A total of 32 head and neck paragangliomas in 28 patients (mean age, 56.1 years ± 16.5 [standard deviation]; 18 female) with therapeutic embolization as stand-alone treatment were evaluated, of which 11 were vagal paragangliomas, 15 jugular/jugulotympanic paragangliomas, and 6 carotid body tumors. After a mean follow-up duration of 33.7 ± 24.4 months, tumor control was achieved in 75%, with significant median tumor volume reduction at 6 months ( P = .02, n = 21). Vagal paragangliomas responded the most to embolization with a significantly decreased median volume from 22.32 cm 3 to 19.09 cm 3 ( P = .008, n = 8). Transient complications occurred in 3.4%., Conclusions: Therapeutic embolization as a stand-alone treatment offers a low-risk control of tumor growth in surgically high-risk lesions, with a significant reduction in tumor volume after treatment. Among the different subtypes, vagal paragangliomas exhibited the strongest and longest regression of the tumor volume., (© 2024 by American Journal of Neuroradiology.)

Introduction: MRI is the imaging modality of choice for assessing patients with encephalopathy. In this context, we discuss a novel biomarker, the "split ADC sign," where the cerebral cortex demonstrates restricted diffusion (high DWI signal and low ADC) and the underlying white matter demonstrates facilitated diffusion (high or low DWI signal and high ADC). We hypothesize that this sign can be used as a biomarker to suggest either acute encephalitis onset or to raise the possibility of an autoimmune etiology., Materials and Methods: A full-text radiological information system search of radiological reports was performed for all entities known to produce restricted diffusion in the cortex excluding stroke between January 2012 and June 2022. Initial MRI studies performed upon onset of clinical symptoms were screened for the split ADC sign., Results: 25 subjects were encountered with a positive split ADC sign (15 female; median age = 57 years, range 18-82). Diagnosis included six herpes simplex encephalitis, three peri-ictal MRI changes, eight PRES, two MELAS, and six autoimmune (3 anti-GABA A R, two seronegative, and one anti-Ma2/Ta). Subjects were imaged at a mean 1.8 days after the onset of symptoms (range 0-8)., Discussion: We present a novel visual MRI biomarker, the split ADC sign, and highlight its potential usefulness in subjects with encephalopathy to suggest acute disease onset or to raise the possibility of an autoimmune etiology when location-based criteria are applied. When positive, the sign was present on the initial MRI and can therefore be used to help focus further clinical and laboratory workup., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Have you ever been in the trenches of a complicated study only to be interrupted by a not-so urgent phone-call? We were, repeatedly- unfortunately., Purpose: To increase productivity of radiologists by quantifying the main source of interruptions (phone-calls) to the workflow of radiologists, and too assess the implemented solution., Materials and Methods: To filter calls to the radiology consultant on duty, we introduced an automatic voicemail and custom call redirection system. Thus, instead of directly speaking with radiology consultants, clinicians were to first categorize their request and dial accordingly: 1. Inpatient requests, 2. Outpatient requests, 3. Directly speak with the consultant radiologist. Inpatient requests (1) and outpatient requests (2) were forwarded to MRI technologists or clerks, respectively. Calls were monitored in 15-minute increments continuously for an entire year (March 2022 until and including March 2023). Subsequently, both the frequency and category of requests were assessed., Results: 4803 calls were recorded in total: 3122 (65 %) were forwarded to a radiologist on duty. 870 (18.11 %) concerned inpatients, 274 (5.70 %) outpatients, 430 (8.95 %) dialed the wrong number, 107 (2.23 %) made no decision. Throughout the entire year the percentage of successfully avoided interruptions was relatively stable and fluctuated between low to high 30 % range (Mean per month 35 %, Median per month 34.45 %)., Conclusions: This is the first analysis of phone-call interruptions to consultant radiologists in an imaging department for 12 continuous months. More than 35 % of requests did not require the input of a specialist trained radiologist. Hence, installing an automated voicemail and custom call redirection system is a sustainable and simple solution to reduce phone-call interruptions by on average 35 % in radiology departments. This solution was well accepted by referring clinicians. The installation required a one-time investment of only 2h and did not cost any money., Competing Interests: Declaration of competing interest None of the authors has any conflict of interest to disclose., (Copyright © 2024. Published by Elsevier Inc.)

Introduction: MRI is negative in a large percentage of autoimmune encephalitis cases or lacks findings specific to an antibody. Even rarer is literature correlating the evolution of imaging findings with treatment timepoints. We aim to characterize imaging findings in autoimmune encephalitis at presentation and on follow up correlated with treatment timepoints for this rare disease., Methods: A full-text radiological information system search was performed for "autoimmune encephalitis" between January 2012 and June 2022. Patients with laboratory-identified autoantibodies were included. MRI findings were assessed in correlation to treatment timepoints by two readers in consensus. For statistical analysis, cell-surface vs intracellular antibody groups were assessed for the presence of early limbic, early extralimbic, late limbic, and late extralimbic findings using the χ 2 test., Results: Thirty-seven patients (female n = 18, median age 58.8 years; range 25.7 to 82.7 years) with 15 different autoantibodies were included in the study. Twenty-three (62%) patients were MRI-negative at time of presentation; 5 of these developed MRI findings on short-term follow up. Of the 19 patients with early MRI findings, 9 (47%) demonstrated improvement upon treatment initiation (7/9 cell-surface group). There was a significant difference (p = 0.046) between the MRI spectrum of cell-surface vs intracellular antibody syndromes as cell-surface antibody syndromes demonstrated more early classic findings of limbic encephalitis and intracellular antibody syndromes demonstrated more late extralimbic abnormalities., Conclusion: MRI can be used to help narrow the differential diagnosis in autoimmune encephalitis and can be used as a monitoring tool for certain subtypes of this rare disease., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Introduction: The purpose of this retrospective study was to compare two, widely available software packages for calculation of Dynamic Susceptibility Contrast (DSC) perfusion MRI normalized relative Cerebral Blood Volume (rCBV) values to differentiate tumor progression from pseudoprogression in treated high-grade glioma patients., Material and Methods: rCBV maps processed by Siemens Syngo.via (Siemens Healthineers) and Olea Sphere (Olea Medical) software packages were co-registered to contrast-enhanced T1 (T1-CE). Regions of interest based on T1-CE were transferred to the rCBV maps. rCBV was calculated using mean values and normalized using contralateral normal- appearing white matter. The Wilcoxon test was performed to assess for significant differences, and software-specific optimal rCBV cutoff values were determined using the Youden index. Interrater reliability was evaluated for two raters using the intraclass correlation coefficient., Results: 41 patients (18 females; median age = 59 years; range 21-77 years) with 49 new or size-increasing post-treatment contrast-enhancing lesions were included (tumor progression = 40 lesions; pseudoprogression = 9 lesions). Optimal rCBV cutoffs of 1.31 (Syngo.via) and 2.40 (Olea) were significantly different, with an AUC of 0.74 and 0.78, respectively. Interrater reliability was 0.85., Discussion: We demonstrate that different clinically available MRI DSC-perfusion software packages generate significantly different rCBV cutoff values for the differentiation of tumor progression from pseudoprogression in standard-of-care treated high grade gliomas. Physicians may want to determine the unique value of their perfusion software packages on an institutional level in order to maximize diagnostic accuracy when faced with this clinical challenge. Furthermore, combined with implementation of current DSC-perfusion recommendations, multi-center comparability will be improved., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: MH is a recipient of grants by GE Healthcare, the Alfred and Annemarie von Sick legacy and the Clinical Research Priority Program (CRPP) Artificial Intelligence in Oncological Imaging Network (University of Zurich). None of the other authors has any conflict of interest to disclose., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Introduction: Synthetic magnetic resonance imaging (SyMRI) is a novel quantitative and qualitative technique that permits the reconstruction of multiple image contrasts and quantitative maps from a single scan, thereby providing quantitative information and reducing scan times. The purpose of this study is to characterize intracranial meningiomas using SyMRI., Methods: The study included 35 patients with meningiomas (6 males, 29 females; mean age 61 ± 17 years; range 21-90 years). Using 3T MR scanners, SyMRI was performed in addition to conventional FSET2, FLAIR, DWI, T1, and T1 with gadolinium. SyMRI software was used to generate T1, T2, and PD quantitative maps. Osirix MD was used to measure quantitative values of T1, T2, and PD using a ROI., Results: We analyzed 42 meningiomas, 8 of which were associated with edema, and 5 contained calcifications. Mean relaxivity values of meningiomas on synthetic T1, T2, and PD maps at 3T MRI were 1382.6 ± 391.7 ms, 95.6 ± 36.5 ms, and 89.1 ± 9.7 pu, respectively. Signal intensities in terms of T1, T2, and PD did not differ significantly between meningiomas with and without edema (p = .994, p = .356, and p = .221, respectively), nor between meningiomas containing and not containing calcifications (p = .840, p = .710, and p = .455, respectively). Values of T1 and T2 measured in meningiomas and the normal-appearing white matter approximated reference values found in the literature with other quantitative methods., Conclusion: The presented method offers a novel approach to characterize meningiomas through their relaxation parameters measured with a SyMRI sequence., (© 2022 The Authors. Brain and Behavior published by Wiley Periodicals LLC.)