AJNR. American journal of neuroradiology最新文献

Aurora (https://aurora-report.com/) is an open-source Web application that introduces structured, standardized reporting for neuroimaging, currently focused on dementia and movement disorders. Developed by and for radiologists and neuroradiologists, Aurora provides a stepwise workflow to support evaluation and reporting. It includes validated atrophy scales such as medial temporal lobe atrophy, global cortical atrophy, entorhinal cortex atrophy, and Koedam posterior atrophy, as well as a systematic approach to describe small vessel disease based on Standards for Reporting Vascular Changes on Neuroimaging, version 2 criteria. Each section offers literature-based guidance and annotated examples for scoring. The platform features built-in calculators for atrophy and movement disorder metrics, including midbrain and pons measurements, midbrain-to-pons ratio, Magnetic Resonance Parkinsonism Index (MRPI), and MRPI version 2.0. Aurora generates structured reports in English (US) or Portuguese (PT). To our knowledge, it is the first freely available platform to unify standardized reporting and calculation for dementia and movement disorders.

CSF-venous fistulas are a common and increasingly recognized cause of spontaneous intracranial hypotension. Most CSF-venous fistulas occur in the thoracic spine and usually arise from nerve root sleeve diverticula. Myelography in the lateral decubitus position is necessary to detect and localize these fistulas, because this technique maximizes contrast density within diverticula, thereby permitting visualization of draining veins. Many modifications to decubitus myelography have been employed in an attempt to improve the conspicuity of CSF-venous fistulas. In theory, maximizing the subarachnoid-venous pressure gradient during imaging should increase contrast flow through CSF-venous fistulas, improving detection of these sometimes-subtle leaks. Augmentation of intrathecal pressure through saline injection before myelography is a simple technique to achieve this and is common in many practices. However, only one prior case report has demonstrated the impact of pressurization on the visualization of a CSF-venous fistula. In this multi-institutional, retrospective case series, we report on a larger cohort of patients in whom CSF-venous fistulas were either occult or nondefinite on myelography without saline pressurization and subsequently definitely seen on myelography with saline pressurization. While our study design precludes determining the incremental yield of saline infusion, it nonetheless provides further support for the value of saline pressurization during myelography in patients with suspected CSF-venous fistulas.

Background and purpose: Advancements in CT myelography (CTM) have improved visualization of CSF-venous fistulas (CVFs), a frequent cause of spontaneous intracranial hypotension (SIH). However, the relative impact of the timing of image acquisition and the contrast density in the subarachnoid space remain unclear. This study compared the effects of timing and contrast density in the ipsilateral subarachnoid space and assessed the impact of other technical factors on CVF conspicuity using a validated instrument to stratify diagnostic confidence.

Materials and methods: A retrospective review of International Classification of Headache Disorders, 3rd edition-confirmed patients with SIH with CVFs was performed. Only fistulas classified as definite by the Duke CSF-Venous Fistula Confidence Score (DCCS) were included. All available CTMs covering each index fistula site were reviewed, excluding examinations occurring after surgery or embolization for a definite CVF. We assigned a DCCS to each acquisition and recorded contrast density in the subarachnoid space ipsilateral to the known CVF and image acquisition time. Patient positioning and scanner type were also collected as potential confounders. Ordinal logistic regression was used to assess associations with CVF conspicuity.

Results: One hundred forty-four patients with 149 definite CVFs comprised the final cohort, from which 222 CTMs and 697 acquisitions were assessed. Both increased contrast density and reduced acquisition time were associated with increased CVF conspicuity in univariate analyses (P < .001). When adjusting for sex, scanner type, and patient positioning in the multivariate model, contrast density and time remained significant predictors of conspicuity (P < .001). Density had a 4-fold greater impact on conspicuity than time, with a 14.3% increase in likelihood of CVF detection per 100 Hounsfield unit (HU) increase in attenuation and an optimal target threshold at 836 HU.

Conclusions: Both contrast density and time influence conspicuity of CVFs on CTM; however, the greater relative impact of density suggests that myelogram technique should prioritize maximization of contrast density for optimal visualization of CVFs. Positioning strategies to increase local contrast pooling may improve CVF detection more effectively than timing adjustments alone.

Background and purpose: A resurgence in recreational misuse of nitrous oxide has been observed in the post-coronavirus disease 2019 (COVID) pandemic era and consequently there has been a surge in cases of nitrous oxide-induced subacute combined degeneration of the cord (N₂O-SACD). It is essential that physicians have an awareness of clinical history, neurologic findings, laboratory investigations, and characteristic features on MR imaging that may suggest a diagnosis of N₂O-SACD.

Materials and methods: This retrospective, hospital-based case series was conducted in a tertiary medical referral center and 1 of 2 National Neuroscience Centers in Ireland. Retrieval of cases was achieved by a keyword search of a radiology PACS archive, using the terms such as "subacute combined degeneration of the cord" and "SACD" to search clinical indications for MR imaging and radiology reports at the institution from July 1, 2012 to December 31, 2024.

Results: Thirty-three patients underwent MRI investigations for suspected subacute combined degeneration of the cord. Twenty-five reported nitrous oxide use. Fourteen of those with reported nitrous oxide use and clinical symptoms had MRI findings suggestive of subacute combined degeneration of the cord. Most prominent symptoms were distal paresthesia (100%), weakness (52%), and ataxia (36%). All cases of N₂O-SACD occurred between 2020 and 2024. The cervical cord was affected in all 14 MRI-positive patients with a characteristic inverted V sign synonymous with subacute combined degeneration of the cord identified in all 14 (100%).

Conclusions: This case series reflects the growing incidence and prevalence of N₂O-SACD. Presentations occurring exclusively between 2020-2024 correlate with the COVID-19 pandemic and its aftermath, which aligns with reported increased misuse across Europe at this time. MRI cervicothoracic spine with T1, T2, and STIR sagittal and T2 axial sequences should suffice for radiologic diagnosis and should be interpreted in conjunction with clinical, laboratory, and, in some cases, electrophysiologic findings.

Background and purpose: Considerable socioeconomic disparities exist among pediatric patients with traumatic brain injury (TBI). This study aims to analyze the effects of social determinants of health on head injury outcomes and to create a novel machine-learning algorithm (MLA) that incorporates socioeconomic factors to predict the likelihood of a positive or negative trauma-related finding on head CT.

Materials and methods: A cohort of patients with blunt trauma younger than age 15 who presented to the largest safety net hospital in New England between January 2006 and December 2013 (n=211) was included in this study. Patient socioeconomic data such as race, language, household income, and insurance type were collected alongside other parameters like Injury Severity Score (ISS), age, sex, and mechanism of injury. Multivariable analysis was performed to identify significant factors in predicting a positive head CT outcome. The cohort was split into 80% training (168 samples) and 20% testing (43 samples) data sets by using stratified sampling. Twenty-two multiparametric MLAs were trained with 5-fold cross-validation and hyperparameter tuning via GridSearchCV, and top-performing models were evaluated on the test data set.

Results: Significant factors associated with pediatric head CT outcome included ISS, age, and insurance type (P < .05). The age of the subjects with a clinically relevant trauma-related head CT finding (median = 1.8 years) was significantly different from the age of patients without such findings (median = 9.1 years). These predictors were utilized to train the machine learning models. With ISS, the fine Gaussian support vector machine (SVM) achieved the highest test AUC (0.923), with accuracy = 0.837, sensitivity = 0.647, and specificity = 0.962. The coarse tree yielded accuracy = 0.837, AUC = 0.837, sensitivity = 0.824, and specificity = 0.846. Without ISS, the narrow neural network performed best with accuracy = 0.837, AUC = 0.857, sensitivity = 0.765, and specificity = 0.885.

Conclusions: Key predictors of clinically relevant head CT findings in pediatric TBI include ISS, age, and social determinants of health, with children younger than 5 at higher risk. A novel fine Gaussian SVM model outperformed other MLAs, offering high accuracy in predicting outcomes. This tool shows promise for improving clinical decisions while minimizing radiation exposure in children.

Background and purpose: SAH is a frequent intracranial finding in patients with trauma and poses significant diagnostic and prognostic challenges. Identifying which patients need closer follow-up because of potential complications of posttraumatic SAH is important because the need for serial imaging is debated. The purpose of this study was to evaluate the rate of posttraumatic subarachnoid hemorrhage enlargement, identify predictors of hemorrhage progression and need for surgical intervention, and propose a risk-stratified approach to follow-up imaging in trauma patients.

Materials and methods: This retrospective study analyzed 32,401 trauma-related NCCT scans from 2 trauma centers during 6 years, identifying 250 cases of traumatic SAH. Patient demographics, clinical presentation, imaging characteristics, and follow-up data were reviewed. Univariate, bivariate, logistic, and linear regression analyses were performed to determine predictors of SAH enlargement and the need for surgical intervention.

Results: Among patients with SAH, 64% were 65 years of age or older, and falls were the most common injury mechanism (66.8%). SAH enlargement occurred in 40/222 (18%) cases that had follow-up CT and was significantly associated with intraparenchymal hemorrhage (IPH), elevated international normalized ratio and prothrombin time, and lower Glasgow Coma Scale scores. Surgical intervention was more commonly required in cases with midline shift or severe traumatic brain injury (Glasgow Coma Scale 3-8). Aneurysms were present in 11/114 patients who underwent CTA, with 9 believed to be the cause of the traumatic episode.

Conclusions: Traumatic SAH is often stable in patients without coexistent hemorrhages or coagulopathy. Risk factors such as IPH and elevated international normalized ratio and prothrombin time should guide follow-up imaging and intervention decisions. A tailored imaging protocol based on risk stratification may optimize patient care while reducing unnecessary imaging.

Background: DTI along the perivascular space (ALPS) has emerged as a measure of cerebral interstitial fluid dynamics, a proposed component of the glymphatic system, which may provide insight into central nervous system fluid transport and waste clearance.

Purpose: Our study aimed to evaluate whether DTI-ALPS can serve as a reliable, noninvasive imaging biomarker of altered interstitial fluid dynamics across the Alzheimer disease (AD) continuum.

Data sources: We searched Scopus, Web of Science, and PubMed for articles published through October 2024.

Study selection: Studies were included if they reported the ALPS index in AD, mild cognitive impairment (MCI), and healthy control (HC) groups. Studies were excluded if they lacked sufficient data or involved overlapping cohorts.

Data analysis: Using standardized mean difference (SMD), we compared the ALPS index in AD and MCI groups to HCs. We assessed the association between the ALPS index and cognitive function by using a random-effects model. A qualitative risk bias assessment was conducted by using the Newcastle-Ottawa Scale (NOS).

Data synthesis: Nineteen studies met the inclusion criteria. The overall ALPS index was significantly lower in AD subjects than in HCs (SMD = -1.07; 95% CI: -1.57 to -0.56). Statistically significant differences were also observed between AD and MCI subjects (SMD = -0.25; 95% CI: -0.40 to -0.10), as well as between MCI and HC subjects (SMD = -0.81; 95% CI: -1.57 to -0.06). Additionally, the ALPS index showed a statistically significant association with Mini-Mental State Examination scores (pooled correlation effect size =0.43; 95% CI: 0.28 to 0.57). A negative correlation was also observed between the ALPS index and amyloid deposition on PET, with a pooled correlation effect size of -0.42 (95% CI: -0.66 to -0.19, P < .001).

Limitations: Potential limitations include heterogeneity across imaging protocols, variability in cognitive assessments, and possible publication bias.

Conclusions: The DTI-ALPS technique showed significant differences among cognitive groups across the AD continuum and was associated with cognitive scores and brain amyloidosis. This provides further evidence that DTI-ALPS could be useful in detecting altered cerebral interstitial fluid dynamics in MCI and AD.

Photon-counting detector CT myelography is an effective technique for the localization of spinal CSF leaks. The initial studies describing this technique used a relatively smooth Br56 kernel. However, subsequent studies have demonstrated that the use of the sharpest quantitative kernel on photon-counting CT (Qr89), particularly when denoised with techniques such as quantum iterative reconstruction or convolutional neural networks, enhances the detection of CSF-venous fistulas. In this clinical report, we sought to determine whether the Qr89 kernel has utility in patients with dural tears, the other main type of spinal CSF leak. We performed a retrospective review of patients with dural tears diagnosed on photon-counting CT myelography, comparing Br56, Qr89 denoised with quantum iterative reconstruction, and Qr89 denoised with a trained convolutional neural network. We specifically assessed spatial resolution, noise level, and diagnostic confidence in 8 such cases, finding that the sharper Qr89 kernel outperformed the smoother Br56 kernel. This finding was particularly true when Qr89 was denoised using a convolutional neural network. Furthermore, in 2 cases, the dural tear was only seen on the Qr89 reconstructions and missed on the Br56 kernel. Overall, our study demonstrates the potential value of further optimizing postprocessing techniques for photon-counting CT myelography aimed at localizing dural tears.

Background and purpose: Sodium (²³Na) MRI provides unique information about ionic homeostasis in the brain. However, in vivo quantification of regional brain sodium is highly challenging due to low SNR and limited spatial resolution. Here, we use our novel anatomically guided reconstruction (AGR) method to overcome these challenges and enable precise quantification of regional brain total sodium concentration (TSC).

Materials and methods: Thirty-four healthy subjects were studied by using a 3T clinical MRI scanner with a dual-tuned (¹H-²³Na) birdcage coil. ²³Na images were acquired by using a twisted projection imaging sequence (TR = 100 ms, TE₁/TE₂ = 0.5/5 ms), while proton (¹H) images were obtained with a standard T1-weighted MPRAGE sequence. AGR was performed with regularization parameters β_r = 0.67, 2.0, and 6.0. As a baseline comparison, standard reconstruction (SR) was also performed by using a regridding algorithm with compensation for nonuniform sampling. To assess partial volume effects (PVEs) on the reconstruction methods, an erosion experiment was conducted. Internal linear calibration using noise-only background and vitreous humor regions was applied to calculate TSC in ROIs including lobar cortical GM, subcortical (including hippocampus, caudate, pallidum, putamen and thalamus), callosal, and whole-brain WM. Bonferroni-corrected pair-wise comparison was performed by using Multivariate Analysis of Variance at a significance level P < .05.

Results: The WM erosion experiments confirmed that TSC_AGR was stabilized beyond 1-voxel erosion in the WM, but TSC_SR was decreasing with erosion increasing, showing a reduced PVE in the AGR images. AGR also shows greater separation in TSC between GM and WM compared with SR (GM TSC_SR = 49.2 ± 4.6 mmol/L, WM TSC_SR = 38.1 ± 3.0 mmol/L; GM TSC_AGR = 48.6 ± 4.9 mmol/L, WM TSC_AGR = 30.5 ± 2.8 mmol/L). We also found smaller variance of TSC_AGR in WM and GM_subcortical compared with TSC_SR.

Conclusions: The AGR helps sodium quantification in healthy human brains by reducing the PVE and variance of TSC in noncortical brain regions. Our normative values of TSC in the brain regions set the stage to better understand derangements of ²³Na metabolism and homeostasis in neurologic disease.

Background and purpose: Motion artifacts remain a key limitation in brain MRI, particularly during 3D acquisitions in cognitively impaired patients. Most deep learning (DL) reconstruction techniques improve the SNR but lack explicit mechanisms to correct for motion. This study aims to validate a DL reconstruction method that integrates retrospective motion correction into the reconstruction pipeline for 3D T1-weighted brain MRI.

Materials and methods: This prospective, intraindividual comparison study included a controlled-motion cohort of healthy volunteers and a clinical cohort of patients undergoing evaluation for memory loss. Each cohort was scanned at distinct imaging sites between October 2022 and August 2023 in staggered periods. All participants underwent 4-fold undersampled 3D MPRAGE with an integrated scout accelerated motion estimation and reduction (SAMER) acquisition. Image volumes were reconstructed by using standard of care methods and the proposed DL approach. Quantitative morphometric accuracy was assessed by comparing brain segmentation results of instructed-motion scans with motion-free reference scans in the healthy volunteers. Image quality was rated by 2 board-certified neuroradiologists by using a 5-point Likert scale. Statistical analysis included Wilcoxon tests and intraclass correlation coefficients.

Results: A total of 41 participants (15 women [37%]; mean age, 58 years) and 154 image volumes were evaluated. The DL-based method with integrated motion correction significantly reduced segmentation error under moderate and severe motion (12.4% to 3.5% and 44.2% to 12.5%, respectively; P < .001). Visual ratings showed improved scores across all criteria compared with standard reconstructions (overall image quality, 4.26 [SD, 0.72] versus 3.59 [SD, 0.82]; P < .001). In 47% of cases, motion artifact severity was improved following DL-based processing. Interreader agreement ranged from moderate to substantial.

Conclusions: Motion-informed DL reconstruction improved both morphometric accuracy and perceived image quality on 3D T1-weighted brain MRI. This technique may enhance diagnostic utility and reduce scan failure rates in motion-prone patients with cognitive impairment.