Board-certified Neuroradiologists Research Articles

CP-14. VOLUMETRIC ANALYSIS OF PAEDIATRIC CRANIOPHARYNGIOMAS: CLINICAL-RADIOLOGICAL CORRELATION STUDY

Abstract BACKGROUND Craniopharyngioma are heterogeneous hypothalamopituitary tumours with solid and cystic components which have a distinct natural history. Neuroimaging follow-up and the definition of progressive disease is challenging due to unpredictable growth of the inflammatory cystic component. METHODS This multicentre retrospective observational study aimed to describe the clinical-radiological correlation of craniopharyngiomas at two paediatric neurosurgery units (GOSH,UK and USP,Brazil). Craniopharyngiomas treated over a 20-year period were identified and standardized clinical outcomes recorded. Baseline MRIs were reviewed and volumetric T1-weighted images segmented by a board-certified paediatric neuroradiologist. RESULTS Of 123 patients, 92 baseline MRIs were available for image analysis (USP=32; GOSH=60). No differences between series were identified in either demography (mean age: USP=9.2±4.6; GOSH=8.2±4.1 years) or tumour characteristics, with tumours being predominantly cystic (USP=75%; GOSH=76%), localised to the sellar/suprasellar region (USP=84%; GOSH: 88%), and on pre-chiasmatic (USP=34%; GOSH=22%) or retro-chiasmatic (USP=59%; GOSH=67%) locations. Pre-chiasmatic tumours were associated with an increased prevalence of visual symptoms at presentation (p=0.006) and worse recovery of visual acuity at long-term follow-up (p=0.021). Regarding volumetric analysis, mean volumes were 16.6±25.1cm3 for the cystic component and 38.3±10cm3 for the solid component. Volumes of the solid and cystic components had no correlation with each other. Larger cystic tumour volumes were correlated with a greater prevalence of diabetes insipidus at presentation (p=0.06). Larger solid tumours were significantly related to younger ages (p=0.02) and had worse PFS in our series. In terms of long-term outcomes, high volume cystic tumours were related to worse hypothalamic outcomes. In multivariate analysis (n=92), Paris classification did not predict long-term outcomes. CONCLUSIONS Volumetric analysis of craniopharyngiomas showed significant correlation with the onset of diabetes insipidus and hypothalamic long-term outcomes. Larger cystic craniopharyngioma were more common in younger patients. The Paris classification did not predict long-term outcomes in multivariate analysis.

Synthesizing 4D Magnetic Resonance Angiography From 3D Time-of-Flight Using Deep Learning: A Feasibility Study.

Objective and background This study aimed to develop a deep convolutional neural network (DCNN) model capable of generating synthetic 4D magnetic resonance angiography (MRA) from 3D time-of-flight (TOF) images, allowing estimation of temporal changes in arterial flow. TOF MRA provides static information about arterial structures through maximum intensity projection (MIP) processing, but it does not capture the dynamic information of contrast agent circulation, which is lost during MIP processing. Considering the principles of TOF, it is hypothesized that dynamic information about arterial blood flow is latent within TOF signals. Although arterial spin labeling (ASL) can extract dynamic arterial information, ASL MRA has drawbacks, such as longer imaging times and lower spatial resolution than TOF MRA. This study's primary aim is to extend the utility of TOF MRA by training a machine-learning model on paired TOF and ASL data to extract latent dynamic information from TOF signals. Methods A DCNN combining a modified U-Net and a long-short-term memory (LSTM) network was trained on a dataset of 13 subjects (11 menand two women, aged 42-77 years) using paired 3D TOF MRA and 4D ASL MRA images. Subjects had no history of cerebral vessel occlusion or significant stenosis. The dataset was acquired using a 3T MRI system with a 32-channel head coil. Preprocessing involved resampling and intensity normalization of TOF and ASL images, followed by data augmentation and arterial mask generation. The model learned to extract flow information from TOF images and generate 8-phase 4D MRA images. The precision of flow estimation was evaluated using the coefficient of determination (R²) and Bland-Altman analysis. A board-certified neuroradiologist validated the quality of the images and the absence of significant stenosis in the major cerebral arteries. Results The generated 4D MRA images closely resembled the ground-truth ASL MRA data, with R² values of 0.92, 0.85, and 0.84 for the internal carotid artery (ICA), proximal middle cerebral artery (MCA), and distal MCA, respectively. Bland-Altman analysis revealed a systematic error of -0.06, with 95% agreement limits ranging from -0.18 to 0.12. Additionally, the model successfully identified flow abnormalities in a subject with left MCA stenosis, displaying a delayed peak and subsequent flattening distal to the stenosis, indicative of reduced blood flow. Visualization of the predicted arterial flow overlaid on the original TOF MRA images highlighted the spatial progression and dynamics of the flow. Conclusions The DCNN model effectively generated synthetic 4D MRA images from TOF images, demonstrating its potential to estimate temporal changes in arterial flow accurately. This non-invasive technique offers a promising alternative to conventional methods for visualizing and evaluating healthy and pathological flow dynamics. It has significant potential to improve the diagnosis and treatment of cerebrovascular diseases by providing detailed temporal flow information without the need for contrast agents or invasive procedures. The practical implementation of this model could enable the extraction of dynamic cerebral blood flow information from routine brain MRI examinations, contributing to the early diagnosis and management of cerebrovascular disorders.

Temporal Muscle Thickness and Sarcopenia Components in Healthy Adults, Validated through Allgeun Diagnostic Tool.

Sarcopenia, characterized by progressive muscle loss and functional decline, poses significant risks, including falls, impaired daily activities, and increased mortality. We developed Allgeun, a novel device that measures handgrip strength, muscle mass, and physical performance. This study aimed to investigate whether temporal muscle thickness (TMT) could be used as a sarcopenia marker and to evaluate the usability of Allgeun. This prospective study enrolled 28 participants without medical or neurological disorders. They underwent three-dimensional T1-weighted imaging using a 3 Tesla magnetic resonance imaging scanner. TMT was measured based on T1-weighted images by a board-certified neuroradiologist. Allgeun was used to measure the following three key components of sarcopenia: muscle strength (handgrip strength), muscle mass (calf and thigh circumference), and physical performance (five times the chair stand test). Correlation analysis was conducted between TMT and the results of the handgrip strength, calf and thigh circumferences, and chair stand tests. There were moderate positive correlations between TMT and calf circumference (r = 0.413, p = 0.029), thigh circumference (r = 0.486, p = 0.008), and handgrip strength (r = 0.444, p = 0.018). However, no significant correlation was observed between TMT and physical performance (r = -0.000, p = 0.998). Our findings underscore TMT's potential as an indicator of sarcopenia, particularly regarding muscle mass and strength. Additionally, we demonstrated that the new device, Allgeun, is useful for screening and diagnosing the severity of sarcopenia.

Implementation of a Survey Spine MR Imaging Protocol for Cord Compression in the Emergency Department: Experience at a Level 1 Trauma Center.

Imaging stewardship in the emergency department (ED) is vital in ensuring patients receive optimized care. While suspected cord compression (CC) is a frequent indication for total spine MR imaging in the ED, the incidence of CC is low. Recently, our level 1 trauma center introduced a survey spine MR imaging protocol to evaluate for suspected CC while reducing examination time to avoid imaging overutilization. This study aims to evaluate the time savings, frequency of ordering patterns of the survey, and the symptoms and outcomes of patients undergoing the survey. This retrospective study examined patients who received a survey spine MR imaging in the ED at our institution between 2018 and 2022. All examinations were performed on a 1.5T GE Healthcare scanner by using our institutional CC survey protocol, which includes sagittal T2WI and STIR sequences through the cervical, thoracic, and lumbar spine. Examinations were read by a blinded, board-certified neuroradiologist. A total of 2002 patients received a survey spine MR imaging protocol during the study period. Of these patients, 845 (42.2%, mean age 57 ± 19 years, 45% women) received survey spine MR imaging examinations for the suspicion of CC, and 120 patients (14.2% positivity rate) had radiographic CC. The survey spine MR imaging averaged 5 minutes and 50 seconds (79% faster than routine MR imaging). On multivariate analysis, trauma, back pain, lower extremity weakness, urinary or bowel incontinence, numbness, ataxia, and hyperreflexia were each independently associated with CC. Of the 120 patients with CC, 71 underwent emergent surgery, 20 underwent nonemergent surgery, and 29 were managed medically. The survey spine protocol was positive for CC in 14% of patients in our cohort and acquired at a 79% faster rate compared with routine total spine. Understanding the positivity rate of CC, the clinical symptoms that are most associated with CC, and the subsequent care management for patients presenting with suspected cord compression who received the survey spine MR imaging may better inform the broad adoption and subsequent utilization of survey imaging protocols in emergency settings to increase throughput, improve allocation of resources, and provide efficient care for patients with suspected CC.

263 Radiographic Structural Changes in Brain Anatomy of Pediatric Fetal Versus Postnatal Myelomeningocele Repair Patients

INTRODUCTION: Postnatally repaired myelomeningocele (MMC) patients have twice the risk of needing shunt treatment for hydrocephalus compared to fetally repaired patients, however it is unknown why exactly this occurs as well as what structural brain changes may be predictive of hydrocephalus. We radiographically characterized anatomic changes in fetally vs postnatally treated infants to understand early developmental anatomy. METHODS: MRIs were characterized by two board-certified neuroradiologists for the following variables: 1) The ratio of ventricular-to-subarachnoid space (VSAR) using bifrontal (BF), left frontal lobe thickness (LV), and extra-axial (EA) spaces as parameters. 2) The ratio of 2 planes within the lateral ventricle (LVR). These ratios, elongation of the choroid plexus glomus and body, and Chiari were measured. RESULTS: 54 MMC repair patients met criteria, yielding 109 MRIs. In the one-to-three month time frame, VSAR at BF and LV parameters in addition to LVR were all significantly different in the fetally repaired group (n = 14) compared to the postnatally repaired group (n = 13, p<0.05). VSAR was not significantly different in early life. Chiari was significantly different in the early life and one-to-three month time between fetal and postnatal repair cohorts (p < 0.05). CONCLUSIONS: Fetally and postnatally repaired MMC brain MRIs were examined by two neuroradiologists to characterize differences in early brain development. This study identified significant differences in the ventricular to subarachnoid space ratio during the one-to-three month time point between fetally and postnatally repaired patients. We suspect that subarachnoid anatomy may be predictive of the need for surgical treatment of hydrocephalus.

Abstract 3785: Clinical and genomic characterization of melanoma brain metastases

Abstract Introduction: Melanoma has a high propensity for brain metastasis (BM). Although advancements in brain-penetrant treatments have resulted in improved central nervous system (CNS) disease control, BMs remain a significant cause of morbidity and mortality. The molecular features of melanoma BM are poorly defined, and there is an unmet need to identify biomarkers associated with CNS-specific outcomes. Methods: We retrospectively identified 109 patients with melanoma BM who underwent craniotomy at Memorial Sloan Kettering Cancer Center (MSK) between 01/2014 and 04/2023. BM specimens were sequenced using MSK-IMPACT, an FDA-approved next-generation sequencing assay covering 341-505 genes with 700X coverage. Clinical characteristics and CNS-specific outcomes were available from 107 patients; CNS-specific radiographic endpoints were verified through direct inspection of contrast-enhanced MRI imaging by a board-certified neuroradiologist. Clinical data included baseline characteristics, prior systemic or radiotherapy (RT), and CNS-directed follow up including recording local progression of disease (POD), regional POD, and development of leptomeningeal disease (LMD). Results: Majority (68%,73/107) patients were male with a median age at the time of primary diagnosis of 56 (range 3-88). Forty-eight patients (45%) had advanced disease (stages III and IV) at the time of initial diagnosis. At the time of BM development, half of the patients had 2-5 intracranial tumors present (50%) with a median diameter of largest BM of 33.4mm (range .9mm-64mm). The median KPS was 80 at the time of BM diagnosis, and 79% had neurologic symptoms prior to resection. 81 patients (76%) were treatment naïve at the time of resection and 56 patients (53%) developed CNS recurrence with the majority of those having local POD (29%,16/56) followed closely by regional POD of 1 lesion (25%,14/56). The most frequent genomic alterations in the cohort were TERT (87%), CDKN2A (50%), BRAF (43%), NRAS (28%), and PTEN (25%). The median fraction genome altered was 0.3047 and the median tumor mutational burden was 13.2 muts/Mb. We compared the genomic profiles of BM tumors of patients that had no progression, local POD, regional POD, and LMD. Compared to patients with no progression, patients with local POD were more likely to have RB1 alterations (18.1% vs 2.1%, p = 0.04, q = 0.83) and patients with LMD were less likely to have TERT alterations (62.5% vs 93.8%, p = 0.03, q = 0.75). Conclusions: Our analysis between genomic markers and clinical outcomes in melanoma BM reveals genomic features which may improve prediction and treatment strategies. Citation Format: Michel Padilla Mazzeo, Henry S. Walch, Rahul Kumar, Jordan Eichholz, Claire Cooper, Nishta Nandakumar, Junchao Shen, Ishaani Khatri, Luke Del Balzo, Anna Skakodub, Emily Miao, Daniel W. Kelly, Kenny Kwok Hei Yu, Jessica Wilcox, Brandon S. Imber, Yao Yu, Yoshiya Yamada, Harish Vasudevan, Ahmet Ilica, Nikolaus Schultz, Luke R. Pike. Clinical and genomic characterization of melanoma brain metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3785.

Sensitivity of Magnetic Resonance Imaging in Detection of Choroidal Metastases

Introduction: The objective of this study was to determine the sensitivity of brain magnetic resonance imaging (MRI) in the detection of choroidal metastasis (CM) from systemic primary cancers. Methods: A retrospective chart review identified patients with clinically confirmed CM seen on the Oncology Service (Byers Eye Institute) between January 2018 and March 2022. Patients had an MRI brain and/or orbits performed within 3 months of CM diagnosis. Evaluation of CM detection by MRI was then divided into two parts: an initial “standard read,” where determination of CM detection was based solely on the original radiology report, to reflect real-world performance, and a subsequent “dedicated read,” for which a board-certified neuroradiologist, blinded to the laterality and location of the CM, reevaluated the studies to provide an objective “gold standard” interpretation regarding the radiographic detection of CM. Results: The study included 42 eyes of 40 patients with confirmed CM. On standard read, MRI detection of CM occurred in 21 of 42 eyes (50%), with no significant difference between MRI brain and orbit protocols (p = 0.249). Features associated with improved detection were increased tumor basal diameter (p < 0.001) and ultrasonographic tumor thickness (p = 0.003). On dedicated read, MRI detection of CM improved to 26 of 33 eyes (76%; limited to eyes with full complement of pre- and post-gadolinium sequences). Post-gadolinium 3D fluid-attenuated inversion recovery (FLAIR) sequence with fat suppression was the most sensitive (88%) for CM detection. 42% and 58% of lesions were visualized using conventional pre-gadolinium T1- and T2-weighted imaging, respectively. Conclusions: MRI sensitivity to detect CM improved from 50% to 76% with focused reinterpretation. Increased utilization of the post-gadolinium 3D FLAIR sequence and increased ocular scrutiny in cancer patients undergoing brain imaging may facilitate earlier diagnosis of CM.

Abstract TMP50: Deep Learning for Hyperdense Middle Cerebral Artery Detection Using High Resolution CT

Introduction: While CT angiography (CTA) remains the gold-standard for non-invasive diagnosis of large-vessel occlusion (LVO), accurate identification of potential thrombectomy patients on non-contrast CT (NCCT) has many practical workflow benefits. However, current evidence suggests that the hyperdense MCA sign on NCCT is an insensitive marker of LVO. In this study, we hypothesize that high-resolution NCCT (HR-NCCT) greatly increases the sensitivity of the hyperdense MCA sign and that a deep learning model can successfully identify the majority of LVO patients on HR-NCCT. Methods: A retrospective cohort of LVO and non-LVO patients with HR-NCCT (0.5-1.0 mm slice thickness) and CTA imaging was identified. For each patient, the location of a hyperdense MCA was annotated by an expert board-certified neuroradiologist after cross-referencing both HR-NCCT and CTA data. A convolutional neural network (CNN) was developed for localization of hyperdense MCA from HR-NCCT imaging only. In brief, the CNN is a 3D contracting-expanding network (18 layers; 596,364 trainable parameters) optimized with deep supervision and class weights. All model statistics are reported after aggregating results from a five-fold cross-validation. Results: A total of 97 LVO-positive and 110 LVO-negative cases were identified. Of the LVO cases, 81.4% (79/97) contained a hyperdense MCA upon expert review. Using these 79 positive (visible dense MCA) and 110 negative cases for training, the model demonstrated an overall 90.0% accuracy in hyperdense MCA detection (92.9% sensitivity, 88.2% specificity). Overall sensitivity was similar for M1 (91.7%) and M2-M3 (94.7%) occlusions. Additionally, of the 18 LVO cases labeled without a hyperdense MCA by expert review, 5 cases were identified correctly by the model and visually confirmed to match occlusion location on CTA. Conclusion: A deep learning model can identify 80.4% of all CTA-confirmed LVO patients using only HR-NCCT, with sensitivity approaching human experts. Combined with ASPECTS evaluation, NCCT-based imaging triage alone may be sufficient to identify the majority of candidate thrombectomy patients.

Bright diffusion sign: A sensitive and specific radiologic biomarker for multinodular and vacuolating neuronal tumor

Background and purposeAccurate differentiation between multinodular and vacuolating neuronal tumor (MVNT) and dysembryoplastic neuroepithelial tumor (DNET) is important for treatment decision-making. We aimed to develop an accurate radiologic diagnostic model for differentiating MVNT from DNET using T2WI and diffusion-weighted imaging (DWI). Materials and methodsA total of 56 patients (mean age, 47.48±17.78 years; 31 women) diagnosed with MVNT (n = 37) or DNET (n = 19) who underwent brain MRI, including T2WI and DWI, were included. Two board-certified neuroradiologists performed qualitative (bubble appearance, cortical involvement, bright diffusion sign, and bright apparent diffusion coefficient [ADC] sign) and quantitative (nDWI and nADC) assessments. A diagnostic tree model was developed with significant and reliable imaging findings using an exhaustive chi-squared Automatic Interaction Detector (CHAID) algorithm. ResultsIn visual assessment, the imaging features that showed high diagnostic accuracy and interobserver reliability were the bright diffusion sign and absence of cortical involvement (bright diffusion sign: accuracy, 94.64 %; sensitivity, 91.89 %; specificity, 100.00 %; interobserver agreement, 1.00; absence of cortical involvement: accuracy, 92.86 %; sensitivity, 89.19 %; specificity, 100.00 %; interobserver agreement, 1.00). In quantitative analysis, nDWI was significantly higher in MVNT than in DENT (1.52 ± 0.34 vs. 0.91 ± 0.27, p < 0.001), but the interobserver agreement was fair (intraclass correlation coefficient = 0.321). The overall diagnostic accuracy of the tree model with visual assessment parameters was 98.21 % (55/56). ConclusionThe bright diffusion sign and absence of cortical involvement are accurate and reliable imaging findings for differentiating MVNT from DNET. By using simple, intuitive, and reliable imaging findings, such as the bright diffusion sign, MVNT can be accurately differentiated from DNET.

P13.05.B INCORPORATION OF AI-BASED AUTOSEGMENTATION AND CLASSIFICATION INTO NEURORADIOLOGY WORKFLOW: PACS-BASED AI TO BUILD YALE GLIOMA DATASET

Abstract BACKGROUND Translation of AI algorithms into clinical practice is significantly limited by lack of large individual hospital-based datasets with expert annotations. Current methods for generation of annotated imaging data are significantly limited due to inefficient imaging data transfer, complicated annotation software, and time required for experts to generate ground truth information. We incorporated AI tools for auto-segmentation of gliomas into PACS that is used at our institution for reading clinical studies and developed a workflow for annotation of images and development of volumetric segmentations in neuroradiology clinical workflow. MATERIAL AND METHODS 1990 patients from Yale Radiation Oncology Registry (2012-2019) were screened. Segmentations were performed using a UNETR algorithm trained on BRaTS 2021 and an internal dataset of manually segmented tumors. AI generated segmentation can be revised and confirmed in PACS. Segmentations were validated by a board-certified neuro-radiologist, after which natively embedded PyRadiomics in PACS was used for direct feature extraction. RESULTS In 7 Months (05/2021 - 08/2021, 03/2022 - 05/2022) segmentations and annotations were performed in 1033 patients (429 female, 604 male, mean age 53 yrs). Dataset includes 595 Grade 4 Gliomas (96 Grade 3, 105 Grade 2, 45 Grade 1, 192 unknown). Molecular subtypes include IDH (129 mutated, 651 wildtype, 253 unknown), 1p/19q (94 deleted or co-deleted, 135 intact, 804 unknown), MGMT promotor (216 methylated, 110 partially methylated, 321 unmethylated, 383 unknown), EGFR (125 amplified, 248 not amplified, 660 unknown), ATRX (41 mutated, 238 retained, 754 unknown), Ki-67 (726 known, 307 unknown) and p53 (639 known, 394 unknown). Classification of gliomas between grade 3/4 and grade 1/2, yielded AUC of 0.85. CONCLUSION We developed a method for incorporation of volumetric segmentation, feature extraction, and classification that is easily incorporated into neuroradiology workflow. These tools allowed us to annotate over 100 gliomas per month, thus establishing a proof of concept for rapid development of annotated imaging database for AI applications.

P11.16.B THE MAYO CLINIC MULTIDISCIPLINARY NF2 CLINIC EXPERIENCE OF BEVACIZUMAB IN NEUROFIBROMATOSIS TYPE 2-RELATED SCHWANNOMATOSIS PATIENTS WITH VESTIBULAR SCHWANNOMAS

Abstract BACKGROUND Neurofibromatosis type 2-related schwannomatosis (NF2) is an autosomal dominant tumor-predisposition syndrome characterized by bilateral vestibular schwannomas (VS) as well as other nervous system tumors. Management decisions for NF2-related VS are typically predicated on tumor size, associated symptoms, patient age, and comorbidities. Observation, surgical resection, and stereotactic radiosurgery can be viable options. In patients with VS associated with NF2, vascular endothelial growth factor A (VEGF-A) inhibitor, bevacizumab, is a systemic treatment option. In this single institution study, we review our clinical experience in patients with NF2 who received bevacizumab for VS and evaluate the effect of bevacizumab treatment on VS growth and symptom progression. MATERIAL AND METHODS This is a retrospective analysis of patients seen at the Mayo Clinic Rochester Multidisciplinary NF2 Clinic. Three-dimensional volumetric data for VS were measured using manual segmentation with Visage PACS software under the direct supervision of a board-certified neuroradiologist. RESULTS Out of 76 patients with NF2 evaluated in the past 3 years, we identified 19 that received treatment with bevacizumab. Median age of NF2 diagnosis was 19 years (range 0.5-61) with a median NF2 phenotype severity score of 2 (range 1-3). Thirteen of these patients have discontinued bevacizumab, accounting for a median duration of 12.2 months (range 3.3-88 months) of bevacizumab treatment. Bevacizumab was discontinued due to hypertension (n=5), proteinuria and renal dysfunction (n=3), tumor progression (n=2), fatigue or other intolerance (n=2), or non-compliance (n=1). The remaining 6 patients are currently receiving bevacizumab treatment for a median duration of 9.4 months as of March 2023 (range 3.7-48.3 months). Fifteen patients had brain MRI data available to evaluate VS change during bevacizumab treatment, with partial response observed in 5 patients, stable disease in 8, and progression in 2. Ten of the 13 patients who stopped bevacizumab had MRI data to evaluate VS change following treatment termination. Within 6 months of bevacizumab discontinuation, 6 patients had rebound growth of their VS between 21-95% from their previous tumor volume, while 4 did not. Three patients with rebound growth went on to have surgery or irradiation for VS management. CONCLUSION Our single institution experience confirms that bevacizumab can slow progression of VS and symptoms associated with VS growth. However, we note that there is the potential for rapid VS growth following bevacizumab discontinuation, for which we propose heightened surveillance imaging and symptom monitoring for at least 6 months upon stopping anti-VEGF therapy.

Evaluation of a compact 3 T MRI scanner for patients with implanted devices

Access to high-quality MR exams is severely limited for patients with some implanted devices due to labeled MR safety conditions, but small-bore systems can overcome this limitation. For example, a compact 3 T MR scanner (C3T) with high-performance gradients can acquire exams of the head, extremities, and infants. Because of its reduced bore size and the patient being advanced only partially into the bore, the associated electromagnetic (EM) fields drop off rapidly caudal to the head, compared to whole-body systems. Therefore, some patients with MR conditional implanted devices can safely receive 3 T brain exams on the C3T using its strong gradients and a multiple-channel receive coil, while a corresponding exam on whole-body MR is precluded. The purpose of this study is to evaluate the performance of a small-bore scanner for subjects with MR conditional spinal or sacral nerve stimulators, or abandoned cardiac implantable electronic device (CIED) leads. The spatial dependence of specific absorption rate (SAR) on the C3T was compared to whole-body scanners. A device assessment tool was developed and applied to evaluate MR safety individually on the C3T for 12 subjects with implanted devices or abandoned CIED leads. Once MR safety was established, the subjects received a C3T brain exam along with their clinical, 1.5 T exam. The resulting images were graded by three board-certified neuroradiologists. The C3T exams were well-tolerated with no adverse events, and significantly outperformed the whole-body 1.5 T exams in terms of overall image quality.

Surgical cytoreduction of deep-seated high-grade glioma through tubular retractor.

Maximal safe resection is the goal of surgical treatment for high-grade glioma (HGG). Deep-seated hemispheric gliomas present a surgical challenge due to safety concerns and previously were often considered inoperable. The authors hypothesized that use of tubular retractors would allow resection of deep-seated gliomas with an acceptable safety profile. The purpose of this study was to describe surgical outcomes and survival data after resection of deep-seated HGG with stereotactically placed tubular retractors, as well as to discuss the technical advances that enable such procedures. This is a retrospective review of 20 consecutive patients who underwent 22 resections of deep-seated hemispheric HGG with the Viewsite Brain Access System by a single surgeon. Patient demographics, survival, tumor characteristics, extent of resection (EOR), and neurological outcomes were recorded. Cannulation trajectories and planned resection volumes depended on the relative location of white matter tracts extracted from diffusion tractography. The surgical plans were designed on the Brainlab system and preoperatively visualized on the Surgical Theater virtual reality SNAP platform. Volumetric assessment of EOR was obtained on the Brainlab platform and confirmed by a board-certified neuroradiologist. Twenty adult patients (18 with IDH-wild-type glioblastomas and 2 with IDH-mutant grade IV astrocytomas) and 22 surgeries were included in the study. The cohort included both newly diagnosed (n = 17; 77%) and recurrent (n = 5; 23%) tumors. Most tumors (64%) abutted the ventricular system. The average preoperative and postoperative tumor volumes measured 33.1 ± 5.3 cm3 and 15.2 ± 5.1 cm3, respectively. The median EOR was 93%. Surgical complications included 2 patients (10%) who developed entrapment of the temporal horn, necessitating placement of a ventriculoperitoneal shunt; 1 patient (5%) who suffered a wound infection and pulmonary embolus; and 1 patient (5%) who developed pneumonia. In 2 cases (9%) patients developed new permanent visual field deficits, and in 5 cases (23%) patients experienced worsening of preoperative deficits. Preoperative neurological or cognitive deficits remained the same in 9 cases (41%) and improved in 7 (32%). The median overall survival was 14.4 months in all patients (n = 20) and in the newly diagnosed IDH-wild-type glioblastoma group (n = 16). Deep-seated HGGs, which are surgically challenging and frequently considered inoperable, are amenable to resection through tubular retractors, with an acceptable safety profile. Such cytoreductive surgery may allow these patients to experience an overall survival comparable to those with more superficial tumors.

Prevalence of intra-osseous veins and venous lakes in the posterior skull base on 3T MRI.

Intra-osseous vessels are normal anatomic structures in the calvarium and skull base. On imaging, these structures-particularly venous lakes-can mimic pathologic abnormalities. This study sought to assess the prevalence of veins and lakes in the skull base on MRI. A retrospective review was completed of consecutive patients that underwent contrast-enhanced MRI imaging of the internal auditory canals. The clivus, jugular tubercles, and basio-occiput were assessed for the presence of both intra-osseous veins (serpentine and/or branching vessels) and venous lakes (well-circumscribed round or oval enhancing structures). Vessels in the adjacent synchondroses major foramina were excluded. Three board-certified neuroradiologists performed independent blinded reviews, with discrepancies agreed upon by consensus. 96 patients were included in this cohort (58.3% female). Mean age was 58.4years (range = 19-85). At least one intra-osseous vessel was identified in 71 (74.0%) patients. 67 (70.0%) had at least one skull base vein, and 14 (14.6%) had at least one venous lake. Both vessel subtypes were observed in 8.3% of patients. Vessels were more commonly observed in women, though this did not reach statistical threshold (p = 0.56). Age was not associated with the presence of vessels (0.59) or vessel location (p values ranged from 0.44-0.84). Intra-osseous skull base veins and venous lakes are relatively common findings on MRI. Both vascular structures should be considered normal anatomy, and care should be taken to not confuse these for pathologic entities.

Prevalence of White Matter Hyperintensities in Young Adults With and Without Mild Traumatic Brain Injury (S28.004)

<h3>Objective:</h3> To determine the prevalence and severity of white matter T2 hyperintensities (WMHs) in young healthy adults and those with recent mild traumatic brain injury (mTBI). <h3>Background:</h3> WMHs on T2-weighted (T2W) MRI are common. Normative data on their prevalence in young healthy adults and in the setting of mTBI is not well characterized, and dependent upon classification system, MRI field strength, scan resolution and imaging parameters. <h3>Design/Methods:</h3> High-resolution 3-Tesla 3D T2W FLAIR and SWI images were retrospectively reviewed from 602 mTBI and control patients who participated in a larger multicenter study of advanced neuroimaging biomarkers. All scans were independently reviewed by 2 board-certified blinded neuroradiologists. All patients with WMHs were identified; patients with excessive WMHs were also identified if ≥5 objective, punctate, white matter foci were present or lesions were &gt;3 mm or atypical in location. <h3>Results:</h3> 413 patients with documented mTBI and 189 controls were analyzed. 32% (134/413) of the mTBI patients and 40% (76/189) of the control patients demonstrated at least 1 WMH on high-resolution T2W-FLAIR imaging. Of these patients, 34% (45/134) of the mTBI group and 34% (26/76) of the control group demonstrated ≥5 lesions, one &gt;3 mm lesion, or lesions in atypical locations. There was no significant difference in number of patients with at least 1 WMH (p=0.064) or excessive WMHs (p=0.313) between mTBI and control groups. <h3>Conclusions:</h3> This represents the largest study cohort of mTBI patients and healthy controls assessing the prevalence of WMHs on high-resolution 3-Telsa 3D T2W-FLAIR. Prevalence of WMHs did not differ between groups and were observed at higher rates than reported in the current literature. These results reflect an evidence-based need to reassess our understanding and clinical interpretation of WMHs in normal healthy adults and patients with mTBI. <b>Disclosure:</b> Dr. Shetty has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Biohaven Pharmaeucticals. Dr. Shetty has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for mTBI, Inc. The institution of Dr. Shetty has received research support from Marker AG. The institution of Dr. Shetty has received research support from Teva Pharmaceuticals Industry. The institution of Dr. Shetty has received research support from GE-NFL. Mr. Westafer has nothing to disclose. Joseph T Nguyen has received personal compensation in the range of $0-$499 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for The American Journal of Sports Medicine. Joseph T Nguyen has received personal compensation in the range of $0-$499 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for The Women’s Journal of Sports Medicine. Miss Coffey has nothing to disclose.

Absence of the torcular, review of venous sinus anatomy, and the simplified dural sinus classification.

Classically, the torcular Herophili is described as the symmetric junction between the superior sagittal sinus (SSS), transverse sinuses (TSs), and straight sinus (SS). However, finding this pattern in practice is not standard. Anatomical variations are common, and different drainage patterns should be expected. Existing literature proposes highly detailed descriptions and classifications of this region. Still, a simplified and practical categorization is not available. We present an anatomical finding of the torcular Herophili discovered on a cadaveric dissection. Then, we conducted a retrospective study examining the 100 most recent cranial magnetic resonance venographies (MRVs) from the Mayo Clinic, labeling them with a new proposed dural sinus classification system. Images were initially classified by two authors and further validated by a board-certified neurosurgeon and a board-certified neuroradiologist from our institution. To measure consistency in image identification, two additional international neurosurgeons were asked to classify a subset of the same MRV images, and their answers were compared. Of the MRV cohort, 33 patients were male and 67 were female. Their ages ranged from 18 to 86years, with a mean of 47.35years and a median of 49years. Upon examination, 53 patients presented as confluent (53%), 9 as SSS divergent (9%), 25 as SS divergent (25%), 11 as circular (11%), and 2 as trifurcated (2%). The inter-rater reliability ranked very good; agreement between the two neurosurgeons was 83% (κ = 0.830, p < 0.0005). The confluence of the venous sinuses is a highly variable anatomical area that is rarely evaluated with neuroimaging before surgery. The classic textbook configuration is not the rule. Using a simplified classification system may increase awareness and hopefully patient safety by preparing the physician for anatomical variations that they will encounter in a surgical or clinical scenario.

676 Anatomic Assessment of L1-S1 Neural Foraminal Dimensions Using Computed Tomography

INTRODUCTION: While radiographic parameters for diagnosis of central lumbar canal stenosis are well known, parameters for diagnosis of neural foraminal stenosis are less well defined. Previous research has used magnetic resonance imaging (MRI) to describe neural foraminal dimensions. However, the blooming artifact on MRI may distort these measurements. There is limited research using computed tomography (CT) to investigate normal neuroforamina dimensions. METHODS: We evaluated CT imaging of 55 female and 55 male subjects between 18 and 35 years of age. Those with history of degenerative disc disease, spondylolisthesis, fracture, neoplasm, trauma, existing spinal hardware, CT imaging performed due to back pain, or previous spinal surgery were excluded from review. Three independent reviewers were trained by a board-certified neuroradiologist to measure L1-S1 neural foraminal dimensions bilaterally. Intraclass correlation coefficient (ICC) two-way mixed model on absolute agreement was used to analyze interrater reliability. Pearson’s correlation was used to evaluate associations among variables. Differences between sexes were analyzed using independent sample t-tests. Measurement differences between disc levels and left- and right-sided measurements were analyzed using paired sample t-tests and one-way analysis of variance. RESULTS: Mean subject age, height, weight, and BMI were 27.16 years, 1.71 m, 88.1 kg, and 29.63 kg/m2, respectively. No moderate or strong correlations were found between measurements and age, height, weight, or BMI for all levels L1-S1. No sex differences were found for measurements at all levels L1-S1. CONCLUSIONS: This study describes CT-based L1-S1 neural foraminal dimensions in patients without pathology affecting the neuroforamina. Dimensions were not strongly influenced by demographic or anthropometric factors.

Aluminum Thin Film Nanostructure Traces in Pediatric EEG Net for MRI and CT Artifact Reduction.

Magnetic resonance imaging (MRI) and continuous electroencephalogram (EEG) monitoring are essential in the clinical management of neonatal seizures. EEG electrodes, however, can significantly degrade the image quality of both MRI and CT due to substantial metallic artifacts and distortions. Thus, we developed a novel thin film trace EEG net ("NeoNet") for improved MRI and CT image quality without compromising the EEG signal quality. The aluminum thin film traces were fabricated with an ultra-high-aspect ratio (up to 17,000:1, with dimensions 30 nm × 50.8 cm × 100 µm), resulting in a low density for reducing CT artifacts and a low conductivity for reducing MRI artifacts. We also used numerical simulation to investigate the effects of EEG nets on the B1 transmit field distortion in 3 T MRI. Specifically, the simulations predicted a 65% and 138% B1 transmit field distortion higher for the commercially available copper-based EEG net ("CuNet", with and without current limiting resistors, respectively) than with NeoNet. Additionally, two board-certified neuroradiologists, blinded to the presence or absence of NeoNet, compared the image quality of MRI images obtained in an adult and two children with and without the NeoNet device and found no significant difference in the degree of artifact or image distortion. Additionally, the use of NeoNet did not cause either: (i) CT scan artifacts or (ii) impact the quality of EEG recording. Finally, MRI safety testing confirmed a maximum temperature rise associated with the NeoNet device in a child head-phantom to be 0.84 °C after 30 min of high-power scanning, which is within the acceptance criteria for the temperature for 1 h of normal operating mode scanning as per the FDA guidelines. Therefore, the proposed NeoNet device has the potential to allow for concurrent EEG acquisition and MRI or CT scanning without significant image artifacts, facilitating clinical care and EEG/fMRI pediatric research.

Multi-Parametric Radiomic Model to Predict 1p/19q Co-Deletion in Patients with IDH-1 Mutant Glioma: Added Value to the T2-FLAIR Mismatch Sign.

The T2-FLAIR mismatch sign has shown promise in determining IDH mutant 1p/19q non-co-deleted gliomas with a high specificity and modest sensitivity. To develop a multi-parametric radiomic model using MRI to predict 1p/19q co-deletion status in patients with newly diagnosed IDH1 mutant glioma and to perform a comparative analysis to T2-FLAIR mismatch sign+. In this retrospective study, patients with diagnosis of IDH1 mutant gliomas with known 1p/19q status who had preoperative MRI were included. T2-FLAIR mismatch was evaluated independently by two board-certified neuroradiologists. Texture features were extracted from glioma segmentation of FLAIR images. eXtremeGradient Boosting (XGboost) classifiers were used for model development. Leave-one-out-cross-validation (LOOCV) and external validation performances were reported for both the training and external validation sets. A total of 103 patients were included for model development and 18 patients for external testing validation. The diagnostic performance (sensitivity/specificity/accuracy) in the determination of the 1p/19q co-deletion status was 59%/83%/67% (training) and 62.5%/70.0%/66.3% (testing) for the T2-FLAIR mismatch sign. This was significantly improved (p = 0.04) using the radiomics model to 77.9%/82.8%/80.3% (training) and 87.5%/89.9%/88.8% (testing), respectively. The addition of radiomics as a computer-assisted tool resulted in significant (p = 0.02) improvement in the performance of the neuroradiologist with 13 additional corrected cases in comparison to just using the T2-FLAIR mismatch sign. The proposed radiomic model provides much needed sensitivity to the highly specific T2-FLAIR mismatch sign in the determination of the 1p/19q non-co-deletion status and improves the overall diagnostic performance of neuroradiologists when used as an assistive tool.

Abstract TP185: Lipoprotein(a) Levels In Patients With Embolic Stroke Of Undetermined Source And Its Association With Non-stenotic Atherosclerotic Disease

Background: Lipoprotein(a) [Lp(a)]has been linked to increased atherosclerotic cardiovascular disease risk however there is limited data on Lp(a) in ischemic stroke subtypes. Current cholesterol management and ASCVD prevention guidelines include Lp(a) &gt;50 mg/dL as a risk enhancer. Methods: This is a retrospective cohort of consecutive embolic stroke of undetermined source (ESUS) patients seen at the Emory Stroke Clinic and underwent Lp(a) testing in the outpatient setting from January 1, 2020 to March 31, 2022. Abnormal levels were defined as ≥ 30 mg/dl. Cerebrovascular imaging was reviewed by a board-certified neuroradiologist who was blinded to Lp(a) data. Results: Of 105 ESUS patients [median age 57 years (IQR 44-68), 51% female, 44% African American (AA)], median Lp(a) was 40 mg/dl (IQR 15-74) with 67 patients (64%) having Lp(a) ≥ 30 mg/dl, 45 (43%) ≥ 50 mg/dl and 30 (29%) having Lp(a) ≥ 70 mg/dl. Lp(a) levels were higher in AAs compared to other races (median 46 mg/dl vs 26 mg/dl , p= 0.002). Lp(a) level ≥ 30 mg/dl was associated with a higher serum D-dimer level median 536 (IQR 337-947, p=0.02), non-large vessel occlusion (LVO) stroke on initial imaging (p=0.012) and absence of MRI-FLAIR sequence abnormalities (p=0.044). In the subset of ESUS patients who underwent CT angiography of the head and neck (n=46), patients with Lp(a) level ≥ 50 mg/dl were more likely to have non-stenotic atherosclerotic plaque ipsilateral to the stroke territory (OR 6.1, 95% CI 1.3-28, p= 0.02). Conclusion: Lp(a) level ≥ 50 mg/dl was present in 43% of our cohort. This may be an under-recognized risk factor in ESUS. Further investigation is needed regarding the impact of Lp(a) on ESUS however our results suggest that ESUS patients with ≥ 50 mg/dl may benefit from a careful assessment of cerebrovascular imaging for ipsilateral non-stenotic atherosclerotic plaque in the territory of the stroke.