Motion Robust MR Fingerprinting Scan to Image Neonates With Prenatal Opioid Exposure.

PURPOSE: To explore whether MR fingerprinting (MRF) scans provide motion-robust and quantitative brain tissue measurements for non-sedated infants with prenatal opioid exposure (POE). STUDY TYPE: Prospective. POPULATION: 13 infants with POE (3 male; 12 newborns (age 7-65 days) and 1 infant aged 9-months). FIELD STRENGTH/SEQUENCE: 3T, 3D T1-weighted MPRAGE, 3D T2-weighted TSE and MRF sequences. ASSESSMENT: The image quality of MRF and MRI was assessed in a fully crossed, multiple-reader, multiple-case study. Sixteen image quality features in three types-image artifacts, structure and myelination visualization-were ranked by four neuroradiologists (8, 7, 5, and 8 years of experience respectively), using a 3-point scale. MRF T1 and T2 values in 8 white matter brain regions were compared between babies younger than 1 month and babies between 1 and 2 months. STATISTICAL TESTS: Generalized estimating equations model to test the significance of differences of regional T1 and T2 values of babies under 1 month and those older. MRI and MRF image quality was assessed using Gwet's second order auto-correlation coefficient (AC2) with confidence levels. The Cochran-Mantel-Haenszel test was used to assess the difference in proportions between MRF and MRI for all features and stratified by the type of features. A P value <0.05 was considered statistically significant. RESULTS: The MRF of two infants were excluded in T1 and T2 value analysis due to severe motion artifact but were included in the image quality assessment. In infants under 1 month of age (N = 6), the T1 and T2 values were significantly higher compared to those between 1 and 2 months of age (N = 4). MRF images showed significantly higher image quality ratings in all three feature types compared to MRI images. CONCLUSIONS: MR Fingerprinting scans have potential to be a motion-robust and efficient method for nonsedated infants. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY STAGE: 1.

Virtual versus true non-contrast images of the brain from spectral detector CT: comparison of attenuation values and image quality.

BACKGROUND: Prior studies focused on utilization of dual-energy computed tomography (DECT) to better detect intracranial pathology and to reduce artifacts. It is still unclear whether virtual non-contrast (VNC) images of DECT can replace true non-contrast (TNC) images. PURPOSE: To compare attenuation values and image quality of VNC images to TNC images of the brain, obtained using spectral detector CT (SDCT). MATERIAL AND METHODS: We retrospectively evaluated patients that underwent head CT with and without contrast material, on a SDCT scanner at our institution (n = 33). The attenuation values of different brain structures were obtained from TNC images, the conventional images of the post-contrast exams (n = 16) or the CT angiography (CTA) (n = 17), and the derived VNC images. In total, 591 regions of interest were obtained, including white and gray matter. Two neuroradiologists independently evaluated the image quality of the VNC and TNC images, using a 5-point Likert scale. RESULTS: The mean difference between the attenuation values on the VNC versus the TNC images was <4 HU for almost all the structures. The difference reached statistical significance (P < 0.05) for the deep gray structures but not for the white matter. The image quality score of the TNC images was 5 in all the patients (excellent gray-white matter differentiation). The scores of the VNC images differed between post-contrast and CTA examinations, with means of 4.9 ± 0.3 (excellent) and 3.2 ± 0.4 (fair), respectively (P < 0.001). CONCLUSION: Our results show minor differences between attenuation values of different brain structures on VNC versus TNC images of SDCT.

High Body Mass Index and Change in Cervical Carotid Artery Position on Serial Scans: A Retrospective Study of an Unexplained Phenomenon.

OBJECTIVE: The purpose of this study was to investigate the relationship between increased body mass index (BMI) and abdominal circumference and prevalence of the change of position of common and internal carotid arteries on serial imaging, termed wandering carotid artery. METHODS: We retrospectively reviewed computed tomography/magnetic resonance imaging neck scans and determined whether the common and internal carotid arteries moved in position on serial scans. We correlated patients' demographic and medical information along with abdominal circumference, BMI, location of the aortic arch, and area of soft tissue surrounding the carotid arteries with the prevalence of a wandering carotid artery. RESULTS: Computed tomography/magnetic resonance imaging neck performed on 56 randomly selected patients between 2017 and 2020 were reviewed. A total of 42.9% of the patients had a wandering common or internal carotid artery. The abdominal circumference and BMI were significantly higher in the patients with wandering carotid arteries compared with the patients without (abdominal circumference = 102.9 ± 14.13 vs 91.61 ± 13.9 cm [ P = 0.01] and BMI = 34.27 ± 8.58 [obese] vs 26.21 ± 4.89 [overweight, P = 0.0001]). After adjusting for age, sex, hypertension, diabetes, atherosclerosis grade, and aortic arch location, the odds of wandering carotid artery was 1.23 (95% confidence interval, 1.1-1.44) times higher for every one-unit increase in BMI. CONCLUSIONS: There is a higher prevalence of wandering common and internal carotid arteries in obese patients with large abdominal circumference irrespective of age, sex, diabetes, hypertension, or carotid atherosclerosis.

"Are They Listening, and Do They Find It Useful?"-Evaluation of Mid-Rotation Formative Subjective and Objective Feedback to Radiology Trainees.

BACKGROUND: Residents commonly receive only end-of-rotation evaluations and thus are often unaware of their progress during a rotation. In 2021, our neuroradiology section instituted mid-rotation feedback in which rotating residents received formative subjective and objective feedback. The purpose of this study was to describe our feedback method and to evaluate if residents found it helpful. METHODS: Radiology residents rotate 3-4 times on the neuroradiology service for 1-month blocks. At the midpoint of the rotation (2 weeks), 7-10 neuroradiology attendings discussed the rotating residents' subjective performance. One attending was tasked with facilitating this discussion and taking notes. Objective metrics were obtained from our dictation software. Compiled feedback was relayed to residents via email. A 16-question anonymous survey was sent to 39 radiology residents (R1-R4) to evaluate the perceived value of mid-rotation feedback. Odds ratios and 95% confidence intervals were computed using logistic regression. RESULTS: Sixty-nine percent (27/39) of residents responded to the survey; 92.6% (25/27) of residents reported receiving mid-rotation feedback in ≥50% of neuroradiology rotations; 92.3% (24/26) of residents found the subjective feedback helpful; 88.4% (23/26) of residents reported modifying their performance as suggested (100% R1-R2 vs 70% R3-R4; OR: 15.4 CI:1.26, >30.0);59.1% (13/22) of residents found the objective metrics helpful (75% R1-R2 vs 40% R3-R4; OR: 3.92 CI:0.74, 24.39) and 68.2% (15/22) stated they modified their performance based on these metrics (83.3% R1-R2 vs 50.0% R3-R4; OR:4.2 CI:0.73, 30.55); and 84.6% (22/26) of residents stated that mid-rotation subjective feedback and 45.5% (10/22) stated that mid-rotation objective feedback should be implemented in other sections. CONCLUSIONS: Majority of residents found mid-rotation feedback to be helpful in informing them about their progress and areas for improvement in the neuroradiology rotation, more so for subjective feedback than objective feedback. The majority of residents stated all rotations should provide mid-rotation subjective feedback.

nnU-Net-based Segmentation of Tumor Subcompartments in Pediatric Medulloblastoma Using Multiparametric MRI: A Multi-institutional Study.

Purpose To evaluate nnU-Net-based segmentation models for automated delineation of medulloblastoma tumors on multi-institutional MRI scans. Materials and Methods This retrospective study included 78 pediatric patients (52 male, 26 female), with ages ranging from 2 to 18 years, with medulloblastomas, from three different sites (28 from hospital A, 18 from hospital B, and 32 from hospital C), who had data available from three clinical MRI protocols (gadolinium-enhanced T1-weighted, T2-weighted, and fluid-attenuated inversion recovery). The scans were retrospectively collected from the year 2000 until May 2019. Reference standard annotations of the tumor habitat, including enhancing tumor, edema, and cystic core plus nonenhancing tumor subcompartments, were performed by two experienced neuroradiologists. Preprocessing included registration to age-appropriate atlases, skull stripping, bias correction, and intensity matching. The two models were trained as follows: (a) the transfer learning nnU-Net model was pretrained on an adult glioma cohort (n = 484) and fine-tuned on medulloblastoma studies using Models Genesis and (b) the direct deep learning nnU-Net model was trained directly on the medulloblastoma datasets, across fivefold cross-validation. Model robustness was evaluated on the three datasets when using different combinations of training and test sets, with data from two sites at a time used for training and data from the third site used for testing. Results Analysis on the three test sites yielded Dice scores of 0.81, 0.86, and 0.86 and 0.80, 0.86, and 0.85 for tumor habitat; 0.68, 0.84, and 0.77 and 0.67, 0.83, and 0.76 for enhancing tumor; 0.56, 0.71, and 0.69 and 0.56, 0.71, and 0.70 for edema; and 0.32, 0.48, and 0.43 and 0.29, 0.44, and 0.41 for cystic core plus nonenhancing tumor for the transfer learning and direct nnU-Net models, respectively. The models were largely robust to site-specific variations. Conclusion nnU-Net segmentation models hold promise for accurate, robust automated delineation of medulloblastoma tumor subcompartments, potentially leading to more effective radiation therapy planning in pediatric medulloblastoma. Keywords: Pediatrics, MR Imaging, Segmentation, Transfer Learning, Medulloblastoma, nnU-Net, MRI Supplemental material is available for this article. © RSNA, 2024 See also the commentary by Rudie and Correia de Verdier in this issue.

Head and neck vessel magnetic resonance angiography appearance and artifacts after therapeutic intravenous ferumoxytol infusion.

Intravenous ferumoxytol infusions are an effective treatment option for iron deficiency anemia. Ferumoxytol contains a superparamagnetic iron oxide core which causes artifacts on multiple MRI brain sequences. However, in our experience, there is not much information on the appearance of intracranial and neck vessels on MR angiography (MRA) after recent therapeutic i.v. administration of ferumoxytol. MRA is an integral part of the work-up for multiple diseases processes including for acute stroke and for detection of aneurysm(s), vasculopathy/vasculitis, vascular malformations, among others and are often performed without the acquisition of MRI brain. Without proper knowledge of the appearance of vessels after administration of i.v. feruomoxytol, radiologists may misinterpret the findings leading to unnecessary further investigation or errant diagnosis. We present the case of a patient who underwent MRI brain and MRA head and neck imaging after recent therapeutic i.v. infusion of ferumoxytol and discuss relevant imaging findings and imaging artifact caused by this medication.

"The Up and Down Approach" to Localize and Exclude Sites of Intraspinal CSF Leaks.

Myelography is a commonly performed procedure to locate cerebrospinal fluid (CSF) leaks in patients with spontaneous intracranial hypotension. Often, the site of leak within the spinal canal cannot be located creating a diagnostic dilemma for clinicians. This technical report describes a novel method to locate and exclude intraspinal CSF leaks in patients with multiple potential sites of CSF leak using a lumbar and cervical approach to inject intrathecal contrast and subsequently performing CT myelography.

Psychological Safety as a New ACGME Requirement: A Comprehensive All-in-One Guide to Radiology Residency Programs.

RATIONALE AND OBJECTIVES: With the Accreditation Council for Graduate Medical Education recently updating their common program requirements to include components of psychological safety as a core principle, radiology training programs and academic radiology institutions will need to evaluate psychological safety within their residency programs and implement practices to sustain a safety culture. This article reviews current literature to present a concise guide for radiology programs on best practices for implementing psychological safety, considering the plethora of literature that is available. MATERIALS AND METHODS: We searched PubMed for published studies evaluating safety culture in medical education and residency. The key words used were Psychological Safety, Education, Radiology, Workplace Culture, and Leadership. RESULTS: Ninety two studies were reviewed that contributed to the topics examined throughout this manuscript, including a brief history of psychological safety, evolving challenges, and a summation of best practices at the institutional, interpersonal, and individual levels that can result in a sustainable psychologically safe culture for radiology residents. CONCLUSION: This article will highlight unique considerations pertinent to a radiology residency program, including suggestions for creating a less stressful environment during case conferences, fostering and supporting residents who are struggling, and inclusive psychological safety practices that also consider non-resident contributors to a residency program, such as attending physician faculty and non-physician radiology technicians.

Decoding Program Signals: A Radiology Residency Program's Experience With the ERAS Supplemental Application.

The ERAS supplemental application has had a profound impact on the interview selection process. At our institution, we found the information in the supplemental application, particularly program signals, especially useful when inviting applicants for interviews. Applicant data was reviewed from this application cycle and the previous cycle and was subcategorized according to various demographic variables. Our analysis revealed that we were able to invite more geographically diverse candidates compared to last year. Program signaling was also beneficial for applicants in demonstrating interest in our program. 47% of interview offers were sent to those who had signaled, despite only 5% of total applications containing a program signal to our institution. Overall, we viewed the supplemental application favorably and reaffirmed its value in the interview selection process.

Motion robust MR fingerprinting scan to image neonates with prenatal opioid exposure.

BACKGROUND: A noninvasive and sensitive imaging tool is needed to assess the fast-evolving baby brain. However, using MRI to study non-sedated babies faces roadblocks, including high scan failure rates due to subjects motion and the lack of quantitative measures for assessing potential developmental delays. This feasibility study explores whether MR Fingerprinting scans can provide motion-robust and quantitative brain tissue measurements for non-sedated infants with prenatal opioid exposure, presenting a viable alternative to clinical MR scans. ASSESSMENT: MRF image quality was compared to pediatric MRI scans using a fully crossed, multiple reader multiple case study. The quantitative T1 and T2 values were used to assess brain tissue changes between babies younger than one month and babies between one and two months. STATISTICAL TESTS: Generalized estimating equations (GEE) model was performed to test the significant difference of the T1 and T2 values from eight white matter regions of babies under one month and those are older. MRI and MRF image quality were assessed using Gwets second order auto-correlation coefficient (AC2) with its confidence levels. We used the Cochran-Mantel-Haenszel test to assess the difference in proportions between MRF and MRI for all features and stratified by the type of features. RESULTS: In infants under one month of age, the T1 and T2 values are significantly higher (p<0.005) compared to those between one and two months. A multiple-reader and multiple-case study showed superior image quality ratings in anatomical features from the MRF images than the MRI images. CONCLUSIONS: This study suggested that the MR Fingerprinting scans offer a motion-robust and efficient method for non-sedated infants, delivering superior image quality than clinical MRI scans and additionally providing quantitative measures to assess brain development.

Unusual progression of osmotic demyelination after liver transplantation on MRI brain.

Osmotic demyelination syndrome, comprised of central pontine and extrapontine myelinolysis, is an important and potentially fatal complication primarily related to rapid overcorrection of serum sodium leading to devastating neurological symptoms. While traditionally presenting in the pons, we report the case of a 43-year-old female patient who recently underwent a liver transplant and developed extrapontine myelinolysis and subsequently central pontine myelinolysis resulting in irreversible spastic quadriparesis. This rare case highlights the variability of presentation of osmotic demyelination syndrome on imaging.

Radiology Performed Fluoroscopy-Guided Lumbar Punctures Decrease Volume of Diagnostic Study Interpretation - Impact on Resident Training and Potential Solutions.

OBJECTIVES: Lumbar punctures performed in radiology departments have significantly increased over the last few decades and are typically performed in academic centers by radiology trainees using fluoroscopy guidance. Performing fluoroscopy-guided lumbar punctures (FGLPs) can often constitute a large portion of a trainee's workday and the impact of performing FGLPs on the trainee's clinical productivity (i.e. dictating reports on neuroradiology cross-sectional imaging) has not been studied. The purpose of the study was to evaluate the relationship between the number of FGLPs performed and cross-sectional neuroimaging studies dictated by residents during their neuroradiology rotation (NR). MATERIAL AND METHODS: The number of FGLPs and myelograms performed and neuroimaging studies dictated by radiology residents on our neuroradiology service from July 2008 to December 2017 were retrospectively reviewed. The relationship between the number of FGLPs performed and neuroimaging studies (CT and MRI) dictated per day by residents was examined. RESULTS: Radiology residents (n = 84) performed 3437 FGLPs and myelograms and interpreted 33402 cross-sectional studies. Poisson regression demonstrated an exponential decrease in number of studies dictated daily with a rising number of FGLPs performed (P = 0.0001) and the following formula was derived: Number of expected studies dictated per day assuming no FGLPs × e-0.25 x number of FGLPs = adjusted expected studies dictated for the day. CONCLUSION: We quantified the impact performing FGLPs can have on the number of neuroimaging reports residents dictate on the NR. We described solutions to potentially decrease unnecessary FGLP referrals including establishing departmental guidelines for FGLP referrals and encouraging bedside lumbar punctures attempts before referral. We also emphasized equally distributing the FGLPs among trainees to mitigate procedural burden.

Venous structures can mimic masses in the foramen magnum.

Benign enhancing lesions at the foramen magnum is a recently described entity and believed to represent a varix or ganglion. These lesions are typically described as being single, located posterior to the intradural vertebral artery, and not attached to the dura. These 2 cases demonstrate previously undescribed variations in appearance of these lesions including contacting the posterior inferior cerebellar artery and lateral epidural plexus/dura, segmental dilatations, transverse and linear configuration, and visualization on an unenhanced CT head. These lesions most likely reflect bridging veins and are structures that clinicians should be aware of to avoid unnecessary follow-up or surgical intervention.

Infrahyoid wandering carotid arteries.

Knowledge of retropharyngeal carotid arteries in patients is important in order to avoid potential catastrophic injuries. Previous studies demonstrated that carotid arteries can change in position at or near the level of the hyoid bone on serial scans. We report the presence of wandering carotid arteries at the level of the cricoid cartilage and superiorly in the neck of a 74-year-old female patient over multiple months. The potential for carotid arteries to randomly change positions in the suprahyoid and infrahyoid neck should be known by clinicians to avoid misdiagnosing occult neck masses and to avoid potential arterial injury during neck surgery. Although the exact etiology for wandering carotid arteries remains uncertain, we propose that reduced axial tension on carotid arteries and increased body mass Index may play a causative role.

Mass Effect Deformation Heterogeneity (MEDH) on Gadolinium-contrast T1-weighted MRI is associated with decreased survival in patients with right cerebral hemisphere Glioblastoma: A feasibility study.

Subtle tissue deformations caused by mass-effect in Glioblastoma (GBM) are often not visually evident, and may cause neurological deficits, impacting survival. Radiomic features provide sub-visual quantitative measures to uncover disease characteristics. We present a new radiomic feature to capture mass effect-induced deformations in the brain on Gadolinium-contrast (Gd-C) T1w-MRI, and their impact on survival. Our rationale is that larger variations in deformation within functionally eloquent areas of the contralateral hemisphere are likely related to decreased survival. Displacements in the cortical and subcortical structures were measured by aligning the Gd-C T1w-MRI to a healthy atlas. The variance of deformation magnitudes was measured and defined as Mass Effect Deformation Heterogeneity (MEDH) within the brain structures. MEDH values were then correlated with overall-survival of 89 subjects on the discovery cohort, with tumors on the right (n = 41) and left (n = 48) cerebral hemispheres, and evaluated on a hold-out cohort (n = 49 subjects). On both cohorts, decreased survival time was found to be associated with increased MEDH in areas of language comprehension, social cognition, visual perception, emotion, somato-sensory, cognitive and motor-control functions, particularly in the memory areas in the left-hemisphere. Our results suggest that higher MEDH in functionally eloquent areas of the left-hemisphere due to GBM in the right-hemisphere may be associated with poor-survival.

Trends in Fluoroscopy Time in Fluoroscopy-Guided Lumbar Punctures Performed by Trainees Over an Academic Year.

RATIONALE AND OBJECTIVES: Fluoroscopy-guided lumbar puncture (FGLP) is an operator-dependent procedure that can contribute to lifetime cumulative radiation dose. Benchmark fluoroscopic times (FTs) have been published for ranges of body mass index (BMI), but trends in FT in FGLPs performed by neuroradiology trainees during their training have not been studied. The purpose of this study was to investigate the trends in FTs in FGLPs performed by neuroradiology fellows in an academic year. MATERIALS AND METHODS: We retrospectively reviewed FGLPs performed at our institution from July 2013 to June 2015 and determined the FT average and standard deviation of residents and non-neuroradiology fellows, neuroradiology fellows, and neuroradiology attendings. We used the Kruskal-Wallis test to evaluate group differences in FT in operator groups and academic quarters and by patient age, BMI, and needle length. Linear and Poisson regression analyses were performed to directly examine the relationship between the number of FGLPs performed and FTs. RESULTS: A total of 776 patients had successful FGLPs; 594 cases (77%) were performed by neuroradiology fellows (n = 14). The average FT and variance for neuroradiology fellows significantly decreased over the year (P = 0.004 and P < 0.001) with an estimated decrease of 0.01 minute of FT per FGLP. BMI, long needle length, and age ≥65 years old significantly affected the average FT (P = 0.03, P < 0.001, and P < 0.001) and FT decreased in all of these subgroups in the academic year. CONCLUSIONS: FT in FGLP cases performed by neuroradiology fellows decreases during the year. Our data can be utilized by radiology training programs and practices as a benchmark to monitor individual operator FT.

Cardiac damage after lesions of the nucleus tractus solitarii.

Humans with central lesions that augment sympathetic nerve activity are predisposed to cardiac arrhythmias, myocardial lesions, and sudden death. Previously, we showed that selectively killing neurons with neurokinin-1 receptors in the nucleus tractus solitarii (NTS) of rats attenuated the baroreflex and, in some animals, led to sudden unexplained death within approximately 2 wk. Interruption of arterial baroreflexes is known to increase sympathetic activity. Here we tested the hypothesis that lesions in the NTS lead to fatal cardiac arrhythmias and myocardial lesions. We studied electrocardiograms, echocardiograms, blood pressure, and heart rate in 14 adult male rats after bilateral microinjection into the NTS of stabilized substance P conjugated to the toxin saporin and compared the variables in five sham control rats and in five animals with toxin injected outside the NTS. Only injection of toxin into the NTS led to increased lability of arterial blood pressure, a sign of baroreflex interruption. Two animals treated with toxin died suddenly. All animals engaged in normal activity until, in two, rapid development of asystole and death over 6-8 min. Cardiac function when examined by echocardiography was normal, but pathologic examination of the heart revealed diffuse microscopic areas of acute coagulation necrosis in the myocardium in five animals, focal subacute necrosis in two animals, and both changes in one animal. This study supports the hypothesis that NTS lesions interrupting the baroreflex may induce cardiac arrhythmias and myocardial changes similar to those seen in humans with central lesions and may lead to sudden cardiac death.