AJNR. American journal of neuroradiology最新文献

Background and purpose: Diffusion MRI measures indicative of white matter integrity have consistently been shown to be altered in the state of the corticospinal tract (CST) and corpus callosum (CC) of patients with amyotrophic lateral sclerosis (ALS). However, diffusion MRI acquisitions are not routinely collected as part of the standard medical imaging of patients with ALS. T1-weighted MRI scans are commonly available in the clinical assessment of most patients with ALS. While visual inspection of these scans reveals little about the cerebral pathology of ALS, analysis of their textural patterns has identified disease-related abnormalities in patients at various stages of the disease. The present study aimed to examine the spatial and temporal profile of CST and CC degeneration in patients with ALS using texture analysis of T1-weighted MRI scans obtained at baseline and at 4- and 8-month follow-ups.

Materials and methods: The study involved data from 64 patients with ALS and 83 healthy controls who participated in the multicenter Canadian ALS Neuroimaging Consortium (CALSNIC) project. The texture feature "autocorrelation" (autoc) was quantified along the superior-inferior course of the CST and along the anterior-posterior direction of the CC of participants.

Results: Progressive textural changes were observed within the bilateral CST, particularly in the primary motor cortex region, posterior limb of the internal capsule, and the cerebral peduncle. As the disease progressed, significant textural changes developed in the middle and anterior parts of the CC. Autoc values in these regions correlated with the degree of upper motor neuron dysfunction on neurologic examination.

Conclusions: Progressive CST and CC degeneration was characterized in ALS using a novel imaging texture analysis approach, with changes observed over an interval of 4 months.

Background and purpose: Brain imaging with MRI or CT is standard in screening for intracranial disease among ambulatory patients with cancer. Though MRI offers greater sensitivity, CT is frequently employed because of its accessibility, affordability, and faster acquisition time. However, the necessity of routinely performing a noncontrast CT with the contrast-enhanced study is unknown. This study evaluates the clinical and economic utility of the noncontrast portion of the brain CT examination.

Materials and methods: A board-certified neuroradiologist reviewed 737 brain CT reports from outpatients at The University of Texas MD Anderson Cancer Center who underwent contrast and noncontrast CT for cancer staging (October 2014 to March 2016) to assess if clinically meaningful findings were identified only on noncontrast CT. A Generative Pretrained Transformers-3 (GPT-3) model was then fine-tuned to extract reports with a high likelihood of unique and meaningful noncontrast findings from 1980 additional brain CT reports (January 2017 to April 2022). These reports were manually reviewed by 2 neuroradiologists, with adjudication by a third reviewer if needed. The incremental cost-effectiveness ratio of noncontrast CT inclusion was then calculated based on Medicare reimbursement and the 95% CI of the proportion of all reports in which noncontrast CT was necessary for identifying meaningful findings.

Results: Seven of 737 reports in the initial data set revealed meaningful findings unique to the noncontrast CT, all of which were hemorrhage. The GPT-3 model identified 145 additional reports with a high unique noncontrast CT finding likelihood for manual review from the second data set of 1980 reports. Nineteen of these reports were found to have unique and meaningful noncontrast CT findings. In total, 0.96% (95% CI: 0.63-1.40) of reports had meaningful findings identified only on noncontrast CT. The incremental cost-effectiveness ratio for the identification of a single meaningful finding on noncontrast CT missed on the contrast-enhanced study was $1855 to $4122.

Conclusions: In brain CT for ambulatory screening for intracranial disease in patients with cancer, noncontrast CT offers limited additional diagnostic value compared with contrast-enhanced CT alone. Considering the associated financial cost, workload, and patient radiation exposure associated with performing a noncontrast CT, contrast-enhanced brain CT alone is sufficient for cancer staging in patients with asymptomatic cancer.

Background and purpose: CSF-venous fistulas (CVFs) are an important and underrecognized cause of spontaneous intracranial hypotension. They are direct communications between the subarachnoid space and paraspinal vein resulting in loss of CSF. We performed a systematic review and meta-analysis to evaluate the prevalence of affected laterality or spinal levels.

Methods and materials: A literature review identified 587 studies for possible inclusion and 43 were selected as relevant by two screeners. Studies from the same institution with data overlap and <3 subjects were removed. Demographic characteristics, side of involvement and spinal levels of CVFs were collected when available and included in the analysis. Pooled prevalence rates were computed, and age and gender distribution across studies were analyzed. Pairwise meta-regression was used, and laterality was further assessed at each spinal level to determine the distribution of right- versus left-sided leaks. Statistical significance was defined as p < 0.05.

Results: CVFs were most common on the right compared to other patterns such as left-sidedness and bilaterally (67% CI: 0.62-0.73; p <0.001). Nearly all were in the thoracic spine (96% CI: 0.93-0.98). T7 and T9 demonstrated the highest prevalence rate for specific spinal levels out of the analyzed CVFs at 19% each. T10 also showed high prevalence rate of 17%. The lumbar and cervical spine demonstrated significantly lower prevalence when compared to the thoracic region (P<0.001). Descriptive analysis of the CVFs by spinal level and laterality demonstrated that the major leak sites were right T7 (7.8%), T6 (6%), and T10 (5.5%).

Conclusions: Localization of CVFs is crucial in therapeutic planning and intervention. We found significantly more on the right utilizing the available literature for analysis. The greatest prevalence rates by level were in the lower thoracic spine at T7, T9, and T10. One possible etiology for this pattern could be the azygous vein and an abundance of arachnoid granulations at these levels.

Background and purpose: Primary central nervous system Epstein-Barr Virus-negative diffuse large B-cell lymphoma (PCNSL) of immunocompetent patients is an aggressive extranodal lymphoma with challenging imaging features. In a large histopathologically-confirmed cohort, we aimed to update conventional MRI characteristics of PCNSL, identify radiological subtypes, and explore early survival differences across subgroups.

Materials and methods: We retrospectively evaluated the consecutive cohort of immunocompetent patients diagnosed with PCNSL who presented to our Lymphoma Unit between 2010 and 2023, enrolling patients with available pre-biopsy 1.5T or 3.0T brain MRI including T1-weighted, T2-weighted, FLAIR, DWI, and post-contrast T1 sequences. Two neuroradiologists independently assessed lesion characteristics (number, location, morphology, volume, signal).Unsupervised hierarchical clustering was applied to identify radiologically-homogeneous subgroups. Associations between subgroup and progression-free/overall survival were assessed using Cox regression in prespecified models adjusted for age, sex, International Extranodal Lymphoma Study Group (IELSG) score and induction regimen.

Results: We enrolled 100 patients (median age 63.9 years, 51% female). Lesions were multifocal in 55% and involved only supratentorial brain in 66%, both supratentorial and infratentorial compartments in 28% and only infratentorial in 6%. Morphology was predominantly mass-like (75%). Median volume was 5.5 mL (IQR 2.0 - 14.9). Relative to brain cortex, T2 signal was hypointense in 63%, isointense in 21%, and hyperintense in 16%; T1 was isointense in 50%, hypointense in 44%, and hyperintense in 6%. Enhancement was solid in 74%, patchy in 7%, closed-ring in 4%, mixed solid-patchy in 15%. Hierarchical clustering identified four subgroups according to radiological characteristics: 1) classical mass-forming (40%): supratentorial, T2-hypointense, solidly enhancing masses; 2) CSF surface-predominant (22%): ependymal, intraventricular, or cortical-pial locations with homogeneous enhancement; 3) infiltrative (20%): small enhancing foci with extensive T2/FLAIR hyperintensity and perivascular enhancement; and 4) atypical mass-forming (18%): large, heterogeneous lesions enriched in necrosis and haemorrhage. Adjusted overall survival differed across subgroups in exploratory analyses (p=0.02), with higher mortality in CSF surface-predominant and infiltrative patterns and lower mortality in the atypical mass-forming group compared with classical mass-forming.

Conclusion: This study updates MRI features of PCNSL and identifies four radiological subgroups, offering a basis for future molecular correlations and prognostic stratification.

Background and purpose: Artificial intelligence (AI) models have shown promise in neuroradiology, yet their real-world generalizability remains uncertain, partly due to variability in imaging acquisition and protocols. We aimed to evaluate the impact of data source, scanner manufacturer, scan mode, slice thickness, and the AI models developed by participating teams on AI performance in this secondary analysis of the 2019 American Society of Functional Neuroradiology (ASFNR) AI Competition.

Materials and methods: We included 1,177 anonymized noncontrast head CT scans from five institutions. Four teams participated, developing models to detect acute ischemic stroke, intracranial hemorrhage, mass effect, and to assess age-appropriate normality. Generalized estimating equations (GEE) were used to evaluate the effects of the aforementioned variables on model performance, and collinearity diagnostics were applied to exclude redundant variables.

Results: Due to collinearity with scanner manufacturer, data source was excluded from the model. Across all tasks, the AI model employed significantly influenced performance. Scanner manufacturer was significantly associated with accuracy in detecting intracranial hemorrhage and acute ischemic stroke but not mass effect or age-based normality. Slice thickness significantly associated with detection of intracranial hemorrhage and mass effect, with thinner slices yielding higher accuracy, but showed no effect on ischemic stroke or normality assessments. Scan mode did not significantly influence performance for any task.

Conclusion: This secondary analysis demonstrates that imaging acquisition and protocol variability may significantly affect AI model performance. Scanner manufacturer, slice thickness, and the developed AI model were significantly associated with model accuracy, whereas scan mode had no significant impact. Among these, the developed AI model consistently proved most influential, reflecting the importance of training data, model architecture, and preprocessing methods.

Aim/objectives/background: This practice parameter was revised collaboratively by the American College of Radiology (ACR), the American Society of Neuroradiology (ASNR), and the Society for Pediatric Radiology (SPR).The document summarizes clinical indications, protocol and equipment specifications, and radiation safety considerations for head CT.

Methods: This practice parameter was revised according to the process described under the heading The Process for Developing ACR Practice Parameters and Technical Standards on the ACR website (https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards) by the Committee on Practice Parameters - Neuroradiology of the ACR Commission on Neuroradiology and the Committee on Practice Parameters - Pediatric Radiology of the ACR Commission on Pediatric Radiology in collaboration with the ASNR and the SPR.

Results: CT of the head is useful for rapid assessment of osseous structures, acute hemorrhage, and calcifications. Primary clinical indications include emergent/urgent imaging of trauma, acute neurologic deficits, ventricle evaluation, interventional planning, and postoperative follow-up. Secondary indications include situations in which MRI is unavailable or contraindicated. Examinations can be performed with conventional energy integrating detector or new photon counting technologies, and should meet specific performance standards. When radiation exposure is deemed medically necessary, dose minimization can be achieved through multiple approaches and depends on patient age, anatomy, and use case.

Conclusions: Appropriate use of head CT requires awareness of clinical indications, protocol and equipment specifications, and radiation safety considerations.

Background and purpose: Flow diversion for intracranial aneurysm treatment traditionally requires dual antiplatelet therapy, creating a clinical dilemma balancing between ischemic and hemorrhagic risks, particularly for those with increased hemorrhagic risks such as ruptured aneurysms. Novel surface-modified flow diversion devices, such as the Pipeline Flex Embolization Device with Shield Technology, reduce thrombogenicity. This technology offers the opportunity to use a de-escalated antiplatelet therapy regimen. However, robust clinical evidence about the safety of this approach on the Pipeline Shield is lacking. Therefore, we compared the safety of single versus dual antiplatelet therapy in patients with intracranial aneurysms treated with this device.

Materials and methods: We performed a retrospective single-center comparative study of patients treated with either single or dual antiplatelet therapy. The primary endpoint was major ischemic stroke (NIHSS score increase of ≥4 points for >24 hours) within 1 year. Secondary endpoints included minor and transient ischemic events, in-stent stenosis, major hemorrhagic events, and aneurysm occlusion rates. The primary endpoint data were analyzed using the Kaplan-Meier method.

Results: A total of 172 patients were included, with 91 in the single antiplatelet therapy group and 81 in the dual antiplatelet therapy group. The main drug used for single antiplatelet therapy was clopidogrel (95.6%). The single antiplatelet therapy group included a significantly greater proportion of patients with aneurysms in higher-risk, non-ICA locations (16.0% vs. 4.4%; P = .004). Despite this baseline imbalance, the estimated 1-year risk of major ischemic stroke did not differ significantly between groups (2.2% [2/91; 95% CI, 0-5.2%] vs. 1.3% [1/81; 95% CI, 0-3.7%]; P = .62). The rates of minor or transient ischemic events, major hemorrhage, in-stent stenosis, and complete aneurysm occlusion were comparable between the groups.

Conclusions: In this exploratory study, no statistically significant difference was observed between the safety profiles of clopidogrel-based single and dual antiplatelet therapies for patients treated with the Pipeline Shield, despite the higher-risk baseline characteristics in the single-therapy cohort. These preliminary findings suggest that clopidogrel monotherapy might be a feasible alternative in select patients, potentially simplifying treatment and reducing DAPT-associated hemorrhagic complications.

Objective: Carotid artery tortuosity, quantified by the carotid elongation ratio (CER), may hinder mechanical thrombectomy (MT). We evaluated whether CER independently predicts procedural efficiency and 90-day functional outcome.

Material and methods: We retrospectively analyzed data from 412 patients from Vall d'Hebron University Hospital prospectively maintained registry, who underwent MT for anterior circulation acute ischemic stroke between 2017 and 2023. CER was computed from pre-treatment CT angiography using an AI-based centerline algorithm. Associations with procedural time (groin-to-reperfusion) and 90-day modified Rankin Scale (mRS) were assessed via correlation, quartile comparison, and multivariable logistic regression adjusted for confounders. Mediation analysis tested whether CER mediates the effect of age on procedural time.

Results: Mean CER was 1.33 ± 0.15. CER correlated with longer procedure time (ρ = 0.11, p = 0.049), but not with final reperfusion success or number of passes. In univariate analysis, higher CER was associated with worse 90-day outcome (mRS 0-2 vs. 3-6: 1.30 vs. 1.35, p = 0.001), and quartile analysis showed a significant trend (p = 0.004). However, CER was not independently predictive after adjustment (adjusted OR per 0.1 CER = 0.97, 95% CI 0.80-1.18, p = 0.77). Mediation analysis showed CER significantly mediated the relationship between age and procedural time (indirect effect = +0.13 min/year, Sobel p = 0.047).

Conclusion: While CER is associated with procedural delay and outcome in unadjusted analyses, it is not an independent predictor of 90-day mRS. Its clinical relevance lies in anticipating technical difficulty, especially in older patients.

This case report uses magnetoencephalography (MEG), electroencephalography (EEG), diffusion kurtosis imaging (DKI), pseudo-continuous arterial spin labelling (pCASL), and resting-state functional MRI (rs-fMRI) to compare female, high-school soccer dizygotic twins who differed in recent concussion history. One twin, "Twin A", sustained her first clinically diagnosed concussion 72 hours before baseline imaging. "Twin B" was not concussed and served as a control for Twin A. Participants completed clinical, neuropsychological, and neurophysiological assessments at baseline (T1), 1 month (T2), and 3 months (T3) timepoints. Imaging and electrophysiology were acquired using a harmonized protocol across modalities. MEG was collected with a MEGIN Triux Neo whole-head system, and 64-channel EEG was acquired simultaneously. MRI was conducted on a 3T Siemens Prisma scanner following the Adolescent Brain Cognitive Development (ABCD) protocol. DKI was processed using FSL to generate fractional anisotropy and mean diffusivity maps. pCASL was analyzed using BASIL to estimate cerebral blood flow. rs-fMRI preprocessing and denoising were performed in CONN, and voxel-wise power spectral density (0.01-0.1 Hz) was computed to quantify low-frequency oscillatory activity. Twin A demonstrated acute symptoms, left frontal hypoperfusion, reduced rs-fMRI power, and increased low-frequency electrophysiological activity at T1, with gradual recovery across modalities. Twin B exhibited stable findings across all assessments. Our findings highlight the potential of multimodal brain imaging to localize sports-related concussion and to help inform return-to-play decisions.

Background: Traumatic brain injury (TBI) remains a major public health issue, with intraparenchymal hemorrhage (IPH) contributing significantly to morbidity and mortality. While computed tomography (CT) is central to initial diagnosis, the value of routine follow-up imaging for IPH remains uncertain. This study aimed to identify clinical and radiographic predictors of IPH enlargement and determine whether certain patients may be safely managed without repeat CT. Such a strategy, could not only reduce avoidable imaging (and its associated radiation), but have implications for patient length of stay, impacting patient safety, care quality, costs and hospital capacity.

Methods: We retrospectively reviewed all non-contrast head CTs performed for trauma at two academic hospitals between July 2018 and May 2024. Reports were screened for acute IPH using defined search terms, and electronic medical records were reviewed for demographics, comorbidities, injury mechanism, imaging findings, management, and outcomes. Enlargement was defined as >1 mm increase in any dimension on follow-up CT. Associations were tested using univariate and multivariable analyses, including logistic regression.

Results: Out of the nearly 25,000 CT scans from patients with acute trauma, 239 patients were identified who had acute IPH. Older age, female sex, hypertension, and antithrombotic therapy were associated with larger baseline hematomas. Enlargement occurred in 30% of cases and was independently predicted by larger initial size (OR 1.02 per mm increase, p = 0.003) and concomitant subarachnoid hemorrhage (OR 3.50, p = 0.002). Enlargement was associated with ICU admission, surgical intervention, and increased mortality (25.8% vs. 8.6%, p = 0.001). Patients with small isolated IPHs (<5 mm) did not demonstrate progression or required intervention.

Conclusions: Initial hematoma size and coexisting subarachnoid hemorrhage strongly predict IPH growth. The rate of enlargement and the absence of intervention for small (< 5mm) isolated IPHs did not warrant follow-up imaging.