Advances in the field of neuromodulation provide patients with medically refractory epilepsy without surgical options the possibility of effective alternative treatments. Three FDA approved electronic neuromodulation devices now exist, vagal nerve stimulation (VNS), responsive neurostimulation (RNS), and deep brain stimulation (DBS). MRI plays a central role in defining stimulation targets. Essential MR safety conditions must be strictly adhered to. Some situations require off-label MR scanning, such as the presence of more than one neuromodulation system or during MR guided therapy, (eg, laser interstitial thermal ablation). Active engagement of well-trained MR safety expert MR physicists is essential in these scenarios.

MR imaging is the imaging modality of choice in epilepsy for detecting structural brain abnormalities, particularly those being considered for surgery. A dedicated epilepsy protocol typically includes high-resolution 3 dimensional (3D) T1-weighted imaging (eg, magnetization prepared rapid acquisition gradient echo) and 3D T2 fluid-attenuation inversion recovery (FLAIR) of the whole brain for anatomic detail and characterization of suspected malformations of cortical development including subtle focal cortical dysplasias. Coronal T2-weighted and/or T2/FLAIR sequences perpendicular to the hippocampus are critical for assessing the architecture of the hippocampus and evaluating for mesial temporal sclerosis and other temporal lobe pathologies.

Auricular acupressure, rooted in traditional Chinese medicine, uses small seeds or metallic beads applied to specific ear acupoints to manage physical and mental health symptoms. It is being used increasingly in oncology and palliative care for relief of pain, nausea, and anxiety. However, its safety during magnetic resonance imaging (MRI) remains unclear due to concerns about potential overheating and image artifact from the metallic beads. Titanium-based beads are commonly used but their MRI compatibility has not been systematically evaluated. In this study, we aimed to quantify potential harm and assess MRI artifacts caused by titanium-based auricular beads, hypothesizing minimal risk and negligible impact on image quality. Titanium auricular beads were tested in a phantom model and on a human volunteer to assess safety and image artifact at 3 tesla (T) and 7T MRI. Standard methodology was used to evaluate radiofrequency-induced heating and magnetic forces. An experienced radiologist interpreted the imaging studies to assess the extent of the artifact caused by the beads. No radiofrequency-induced heating or magnetic forces were observed at either field strength. Image artifact was minimal and did not interfere with diagnostic interpretation. These findings suggest that the titanium beads tested pose negligible risk and have minimal impact on image quality. However, the clinicians should remain aware of bead composition and screen for nontitanium materials to ensure patient safety and preserve image quality for patients undergoing MRI. Trial Registration: N/A.

In epilepsy patients lacking magnetic resonance imaging-visible lesions such as focal cortical dysplasia (FCD), surgical resections target regions with abnormal electroencephalographic (EEG) activity. However, histopathological identification of subtle cortical architectural abnormalities in these specimens remains challenging. We investigated whether artificial intelligence (AI)-based morphometric and spatial analysis of NeuN-stained cortical sections could detect neuronal architectural disorganization in epilepsy resections, including regions without definitive histologic dysplasia. Whole slide images were generated from 83 FCD regions and 19 neurologically normal autopsy controls. Regions of interest were annotated in QuPath as FCD, FCD-adjacent, FCD-distant, apparently normal (abnormal EEG without histologic dysplasia), and true normal (autopsy controls). NeuN-positive neurons were detected using QuPath (90% sensitivity, 12% false positive rate). Spatial and morphometric features-including neuronal clustering, distribution inhomogeneity, and nuclear morphology-were extracted and used to train a multinomial, Least Absolute Shrinkage and Selection Operator-regularized regression classifier. The classifier achieved 70.6% accuracy in subregion classification and 88.2% accuracy in overall specimen diagnosis. Notably, regions with abnormal EEG but lacking histologic dysplasia exhibited quantifiable architectural disorganization similar to those seen in areas adjacent to FCD and distinct from control tissue. AI-driven analysis of neuronal morphology and spatial distribution reveals subtle cortical disorganization in epilepsy resections, including in histologically ambiguous regions. Further investigation is warranted to determine if this methodology can enhance the diagnostic yield of neuropathological evaluation and support more precise surgical targeting in epilepsy.

We describe a simple, reproducible patient-positioning protocol to facilitate acquisition of plain film radiographs that reliably depict CI magnet orientation, thereby minimizing the need for repeat imaging or CT to determine the presence of magnet displacement. This approach leverages widely available imaging equipment and can be easily adopted in multiple patient care settings without specialized hardware or software. The image below depicts plain skull radiographs obtained using the standardized patient positioning protocol demonstrating bilateral cochlear implant magnet position before (A, B) and after (C, D) manual reduction.

BACKGROUND AND PURPOSE:7T MRI has specific technical features that are advantageous for epilepsy. This study aims to evaluate whether new potentially epileptogenic abnormalities can be identified on 7T MRI in patients with epilepsy with negative 3T MRI findings. MATERIALS AND METHODS:Clinical 7T epilepsy MRI examinations in patients with prior negative 3T imaging findings were retrospectively reviewed by 3 neuroradiologists. Their consensus 7T scan interpretations were reviewed by a neurologist for concordance with EEG findings. Descriptive characteristics of any 7T MRI abnormalities and their locations were recorded. The clinical and EEG findings in subjects with abnormal 7T scan findings were compared with those of subjects without a 7T abnormality. RESULTS:In patients with epilepsy with nonlesional 3T MRI, new abnormal findings were identified on 7T MRI in 36% (18/50) of cases. Of the 14 pediatric cases, there were 7T MRI abnormal findings in 6/14 (42.9%). Across all cases, a total of 21 discrete abnormal findings were identified, including meningoencephaloceles (5/21, 23.8%), cavernous malformations/possible vascular lesions (5/21, 23.8%), focal cortical dysplasia (3/21, 14.3%), gray matter heterotopia (3/21, 14.3%), mesial temporal sclerosis (3/21, 14.3%), 1 indeterminant hippocampal morphology finding (1/21), and 1 case of a diffuse migrational abnormality (1/21). Noninvasive EEG monitoring unit data were concordant with the location of 7T abnormalities in 60.0% (9/15) of cases with these clinical data available. Participants with generalized seizures (OR, 0.2; 95% CI, 0.041-0.75) and those with multiple seizure types (OR, 0.14; 95% CI, 0.027-0.52) were significantly less likely to have new potentially epileptogenic lesions detected at 7T. Two 7T cases with abnormal findings underwent surgical resection with good clinical outcomes (Engel Class IA). CONCLUSIONS:In clinical practice, 7T MRI revealed additional epileptogenic lesions in 36% of nonlesional 3T MRI cases.

MR imaging is a central component of the diagnosis and management of epilepsy, especially in identifying candidates for surgical resection or planning for neuromodulatory interventions. A standardized, high-resolution epilepsy protocol enables the detection of subtle epileptogenic abnormalities. Radiologists must be attuned to the wide spectrum of lesions and aware of potential imaging pitfalls.

Since the introduction of the American College of Radiology (ACR) MRI safety guidelines in 2002, the indications for use of MRI in clinical care and research have continued to expand. Similarly, MRI technologies have evolved, with multiple field strengths now available for human imaging. While several publications have updated the ACR recommendations since the first guidelines, a single source in a structured format was lacking. Accordingly, the ACR Committee on MR Safety recently updated the online ACR Manual on MR Safety that compiles ACR recommendations for safe use of MRI equipment in humans into a single document. This review describes the new structure of the ACR Manual on MR Safety, discusses new content, indicates gaps in knowledge that require further research, and explains the rationale for the Committee on MR Safety recommendations on certain topics, such as remote operation of MRI systems.

Epilepsy is a common disease with significant impacts on patients. Evaluation and management can be dynamic over time. After an initial seizure, focus is on risk stratification to decide whether treatment is necessary. Once epilepsy is diagnosed, then management with antiseizure medications is first-line in treatment, with individual patient factors considered in treatment decision making. Surgical treatments and invasive neuromodulation may be used if patients fail at least 2 appropriate seizure medications.

IV contrast media improve the diagnostic power of radiology examinations. These media include gadolinium-based contrast media and iron oxide nanoparticles for MRI, iodinated contrast material for CT, microbubbles for ultrasound, and radiopharmaceuticals for nuclear medicine. As do all medications, contrast media carry risks, which may be heightened in the conditions of pregnancy and lactation. Radiologists must understand the potential risks from contrast media exposure to the pregnant patient, fetus, and nursing infant, as well as understand these administrations' impact on the clinical utility of examinations. This article reviews the available literature on these media, along with key regulatory bodies' and professional societies' current recommendations for their use, in the settings of pregnancy and lactation. This knowledge should help radiologists make well-reasoned risk-benefit analyses regarding contrast media administration and allow informed consent discussions with pregnant and nursing patients for whom contrast media administration is being considered. This information and analysis can also assist facilities in designing policies and standard operating procedures of possible clinical benefit to the pregnant patient, fetus, or nursing infant, balancing contrast media exposure considerations against augmented diagnostic capabilities.

For acute stroke patients requiring MR examination and unable to provide a reliable history, screening for potentially MRI-incompatible objects (PMIOs) typically necessitates the use of plain-film radiographs (PFRs). However, using a whole body CT scout at the time of non-contrast head CT scans can preclude critical delays. Here, we aim to compare the effectiveness of PFRs and CT scouts in detecting PMIOs. A case-control study was conducted at a tertiary care institution, involving 408 imaging studies from 200 patients, half of which contained PMIOs. The diagnostic performances of CT scouts and PFRs were evaluated by six blinded readers, including two board-certified neuroradiologists, one neuroradiology fellow, and three radiology residents. 2448 interpretations from the 6 readers were analyzed. The diagnostic performance of combined CT scout images (full-body and regional) was not significantly different from that of PFRs for all six readers (p = 0.06). However, PFRs outperformed full-body CT scouts in PMIO detection (p = 0.01), with no significant differences observed between PFRs and regional CT scouts (p = 0.4). Notably, the diagnostic accuracy of the radiology residents was found to be equivalent to radiologists across all imaging techniques. Integrating CT scouts in acute stroke protocols may help expedite MRI screening. The scouts should include the head, neck, chest, upper arms, abdomen, pelvis, and thighs. Including radiology residents in the screening process for PMIOs may be an avenue for resource optimization in acute care settings.

Extremely severe nausea was experienced by four subjects positioned prone on a 7T scanner table with their arm extended overhead for a wrist examination and their head positioned approximately 10-20 cm above the magnet's central axis. Movement through the large static and spatial field gradients of current 7T MRI scanner magnets typically causes mild vestibular activation which is well tolerated by most individuals. However, when positioned off-axis, the head moves through regions of even larger and more rapidly changing magnetic fields which in the current study were sufficient to induce the extremely severe nausea. Ensuring the head remains on-axis mitigates this effect.

ObjectiveTo describe the development, implementation, and validation of a radiology-administered protocol to obtain magnetic resonance imaging (MRI) in patients with cochlear implants and auditory brainstem implants without magnet removal.Study DesignRetrospective review and description of novel care pathway.MethodsA radiology-administered protocol was designed based on careful input from the radiology safety committee and neurotology. Radiology technologist training modules, consent instructions, patient educational material, clinical audits, and other safeguards were implemented, with samples provided in this report. The primary outcomes measured included instances of magnet displacement during MRI and premature termination of MRI studies secondary to pain.ResultsBetween June 19, 2018, and October 12, 2021, 301 implanted ears underwent MRI without magnet removal, including 153 devices housing diametric MRI-conditional magnets, and 148 implants with conventional axial (i.e., nondiametric) magnets. Among cases with diametric MRI-conditional magnets, all studies were completed without magnet dislodgement or need to terminate imaging early due to pain. Among cases with conventional axial (nondiametric) magnets, 29 (19.6%) MRI studies were stopped prematurely secondary to pain or discomfort; the overall rate of this event was 9.6% (29 of 301) among the entire study cohort. In addition, 6.1% (9 of 148) experienced confirmed magnet displacement despite headwrap placement; the overall rate among all cases was 3.0% (9 of 301). Eight of these patients received successful external magnet reseating through manual pressure on the external scalp without surgery, and one required surgical replacement of the magnet in the operating room. There were no documented instances of hematoma, infection, device or magnet extrusion, internal device movement (i.e., gross receiver-stimulator migration), or device malfunction in this cohort related to MRI.ConclusionsWe present the successful implementation of a radiology-administered protocol designed to streamline care for cochlear implant and auditory brainstem implant recipients who require MRI and ease clinical demands for otolaryngology providers. Examples of resources developed, including a process map, radiology training modules, consent instructions, patient educational materials, clinical audit, and other procedural safety measures are provided so interested groups may consider adapting and implementing related measures according to need.

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.

ABSTRACT OBJECTIVE MRI and CT are indispensable imaging modalities for the evaluation of patients with neurologic disease, and each is particularly well suited to address specific clinical questions. Although both of these imaging modalities have excellent safety profiles in clinical use as a result of concerted and dedicated efforts, each has potential physical and procedural risks that the practitioner should be aware of, which are described in this article. LATEST DEVELOPMENTS Recent advancements have been made in understanding and reducing safety risks with MR and CT. The magnetic fields in MRI create risks for dangerous projectile accidents, radiofrequency burns, and deleterious interactions with implanted devices, and serious patient injuries and deaths have occurred. Ionizing radiation in CT may be associated with shorter-term deterministic effects on biological tissues at extremely high doses and longer-term stochastic effects related to mutagenesis and carcinogenesis at low doses. The cancer risk of radiation exposure in diagnostic CT is considered extremely low, and the benefit of an appropriately indicated CT examination far outweighs the potential risk. Continuing major efforts are centered on improving image quality and the diagnostic power of CT while concurrently keeping radiation doses as low as reasonably achievable. ESSENTIAL POINTS An understanding of these MRI and CT safety issues that are central to contemporary radiology practice is essential for the safe and effective treatment of patients with neurologic disease.