AJNR. American journal of neuroradiology最新文献

Background and purpose: Subpial hemorrhage (SPH) is a rare form of intracranial hemorrhage, typically observed in neonates. It differs from subarachnoid and subdural hemorrhages in both anatomic location and underlying pathophysiology. The primary aim of this study was to describe the distinct fetal MRI features of cerebellar SPH.

Materials and methods: This retrospective multicenter study included 24 fetuses, aged between 20 + 5 and 34 + 0 weeks of gestation, from 3 institutions. Postmortem 3T MRI and neuropathologic work-up were available for 4 cases and 1 postnatal MRI.

Results: SPH was located infratentorially along the cerebellum and vermis in all 24 cases. SPH was observed as either unilateral, bilateral, or multifocal, with several distinct morphologic patterns, crescentic or spherical/punctate shapes along the cerebellar surface. Postmortem MRI in one case confirmed the prenatal MRI findings, and neuropathological analysis confirmed SPH extending from the pia-arachnoid through the molecular layer and hemosiderin-containing macrophages within the external granular layer associated with reduced and disrupted Bergmann glial processes in areas adjacent to SPH.

Conclusions: Fetal cerebellar SPHs are characterized by crescentic foci of signal abnormality that appear "attached" to the cerebellar surface. Cerebellar SPH constitutes a distinct entity that may be detected on prenatal imaging, either in isolation or in association with fetal germinal matrix-intraventricular hemorrhage.

Background and purpose: T1-weighted hypointense lesions resulting from MS reflect chronic, irreversible tissue injury mediated by autoimmune inflammation and are associated with neurologic disability. The evolution of such lesions is heterogeneous in the presence or absence of disease-modifying therapy (DMT). We investigated dynamic changes of T1-weighted hypointense lesions along with total T1-weighted hypointense lesion volumes to further understand MRI features that may reflect clinically silent disease activity.

Materials and methods: A retrospective study was performed involving people with MS with 3 consecutive standardized MRI time points within a single academic center. Individuals with formal neuroradiology interpretations lacking evidence of T1-weighted hypointense lesion change were included. Approximately 8-12 nongadolinium-enhancing T1-weighted hypointense lesions measuring at least 3 mm² were selected from a 3D MPRAGE from each individual. Total T1-weighted hypointense lesion volumes were also quantified at each time point. The Lambda, Mu, and Sigma method was used to estimate the SD of the annualized volume rate of change as a function of the lesion volume at the prior time point. The longitudinal associations between treatment class on T1-weighted hypointense lesion dynamics and relationship to patient- or physician-reported disease worsening, acute clinical relapse, and MRI advancement were evaluated.

Results: The cohort comprised 91 people (71.4% women; mean disease duration of 9.32 years; SD: 7.22 years) who were primarily white (80.2%). Of treated individuals, most were exposed to non-high-efficacy DMTs at least once (48.4%). In total, 273 MRI studies yielding 790 T1-weighted hypointensities were studied longitudinally. Predominantly enlarging T1-weighted hypointense lesions were seen in 82.4% of individuals over 3 MRI time points. The odds of overall T1-weighted lesion volume contraction did not differ between those on high-efficacy treatment (P = .71) or those untreated (P = .85), compared with non-high-efficacy agents. Treatment group did not influence total change in T1-weighted hypointense lesion volumes, and correlations with clinical or MRI outcomes were not observed.

Conclusions: Current DMT classifications may have minimal influence on T1-weighted hypointense outcomes, highlighting the need for treatments that directly target ongoing tissue injury.

Background and purpose: Stent-assisted coiling (SAC) is widely used for the treatment of wide-neck, unruptured intracranial aneurysms. However, direct comparative data between different stent platforms remain limited. This study aimed to evaluate the safety and efficacy of the Low-profile Visualized Intraluminal Support (LVIS) stent versus the Neuroform Atlas stent in the treatment of unruptured ICA aneurysms measuring <10 mm in diameter.

Materials and methods: A retrospective analysis was performed on 287 unruptured ICA aneurysms (<10 mm) in 247 patients treated with SAC using either the LVIS or Neuroform Atlas stent across 3 affiliated institutions between March 2017 and December 2023. Patients were divided into 2 groups: group A (Neuroform Atlas) and group L (LVIS). After 1:1 propensity score matching for demographic, clinical, anatomic, and procedural variables, key outcomes including Raymond class 1 occlusion, volume embolization ratio, and periprocedural complications were compared between the 2 groups.

Results: Among the 287 aneurysms, 237 (82.6%) were treated with the Neuroform Atlas stent and 50 (17.4%) with the LVIS stent. Propensity score matching yielded 46 matched pairs. Immediately after treatment, group L demonstrated significantly higher rates of complete occlusion and a greater volume embolization ratio compared with group A (P = .022 and .004, respectively). At the 1-year follow-up, the complete occlusion rate remained significantly higher in group L than in group A (52% versus 24%; P = .007). The incidence of ischemic and hemorrhagic complications did not differ significantly between the 2 groups.

Conclusions: For unruptured ICA aneurysms <10 mm in diameter, SAC using the LVIS stent was associated with a significantly higher rate of complete occlusion at 1 year compared with the Neuroform Atlas stent, without an increase in periprocedural complications. These results support the safety and efficacy of the LVIS stent in achieving favorable long-term angiographic outcomes in small- to medium-sized unruptured ICA aneurysms.

Background and purpose: Spontaneous intracranial hypotension (SIH) is caused by CSF leakage at the spinal level, resulting in craniospinal CSF depletion and often debilitating symptoms. While changes in intracranial CSF volume in SIH, particularly early depletion and normalization after treatment, are documented, reports of spinal CSF volumetry remain scarce. This study aimed to quantify intrathecal spinal CSF volume in patients with SIH before and after definitive leak closure and compare it with that in a non-SIH control cohort.

Materials and methods: This retrospective, single-center study included 35 patients with SIH with confirmed spinal CSF leaks (types 1-3) and 10 non-SIH controls. All patients with SIH underwent surgical or endovascular leak closure and had high-quality pre- and posttreatment isotropic 3D T2-weighted MR imaging. Spinal intrathecal CSF volume was measured using semi-automated segmentation, excluding spinal longitudinal epidural fluid collections (SLEC), if present. Paired and unpaired statistical tests were applied.

Results: In total 18, SLEC-positive (+) and 17 SLEC-negative (-) patients and 10 non-SIH controls were evaluated. After successful leak closure, spinal CSF volume increased significantly in patients with SIH (+13%, P < .001). This increase was seen in both SLEC+ (+18%, P < .001) and SLEC- (+5%, P = .02) subgroups. No significant difference was observed between patients with SIH pretreatment and controls. However, posttreatment volumes in patients with SIH were significantly higher than those in controls (+13%, P = .04).

Conclusions: Spinal CSF volumetry reliably detects a significant increase in intrathecal CSF volume following definitive leak closure in patients with SIH. Notably, posttreatment spinal CSF volumes exceeded those of non-SIH controls, suggesting a potential compensatory mechanism with overshooting CSF volume after prolonged CSF depletion.

Background and purpose: Gadolinium-based contrast agents (GBCAs) are essential in pediatric neuroimaging, enabling visualization of pathology that disrupts the blood-brain barrier. Gadopiclenol is a new macrocyclic GBCA with higher T1 relaxivity, permitting a 50% dose reduction while maintaining diagnostic quality. However, it is unknown whether this higher relaxivity alters background extra-axial vascular enhancement. We hypothesized that gadopiclenol, despite its lower dose, would increase background enhancement on postcontrast pediatric brain MRI compared with gadoterate meglumine (Gd-DOTA).

Materials and methods: In this retrospective observational study, 302 contrast-enhanced brain MRI studies in patients aged 2-18 years were reviewed: 151 with gadopiclenol (0.05 mmol/kg) and 151 with Gd-DOTA (0.1 mmol/kg). Postcontrast sequences included 3D T1 spin-echo (SE), 3D T1 spoiled gradient-echo (SPGR), 2D T1 TSE, and 2D FLAIR. Two neuroradiologists established binary enhancement categories based on sulcal enhancement thresholds (high versus low). One reader assigned scores for all studies; a second reader evaluated a subset for interobserver agreement. Logistic regression assessed the association between contrast agent and high enhancement, adjusting for age, sex, anesthesia, and scanner field strength.

Results: Gadopiclenol was independently associated with significantly greater odds of high extra-axial enhancement on all T1-weighted sequences: 3D T1 SE (OR = 10.2; P < .001), 3D T1 SPGR (OR = 10.7; P < .001), and 2D T1 TSE (OR = 14.0; P < .001). Anesthesia was also an independent predictor of high enhancement on 3D SE and SPGR. On 2D FLAIR, contrast agent had no effect; instead, younger age was associated with high enhancement (P = .022), with an age-anesthesia interaction suggesting attenuation of this effect under sedation. Interobserver agreement was moderate to substantial (κ = 0.530-0.632).

Conclusions: Gadopiclenol increases background extra-axial enhancement on T1-weighted postcontrast sequences in pediatric brain MRI, likely reflecting its higher relaxivity. Radiologists should be aware of this effect to avoid misinterpretation as leptomeningeal pathology. Postcontrast FLAIR remains unaffected and continues to serve as a reliable sequence for detecting true meningeal disease.

Background and purpose: Isolated congenital middle ear malformation (CMEM) contributes significantly to congenital hearing loss and growth problems. This study aims to compare 0.1-mm isotropic ultra-high-resolution CT (U-HRCT) and conventional high-resolution CT (HRCT) for assessing isolated CMEM, using surgical exploration as the standard.

Materials and methods: This single-center retrospective study included patients with surgically confirmed isolated CMEM who underwent U-HRCT or HRCT from January 2015 to April 2025. Middle ear abnormalities were identified based on operative outcomes and 4 subtypes were classified via the Teunissen standard. Two neuroradiologists blinded to surgical outcomes reviewed CT images for 10 subtle structural abnormalities and specific subtypes. The comparison of U-HRCT and HRCT in terms of interobserver and intraobserver agreement and detection of structural abnormalities and subtypes of CMEM were analyzed.

Results: The U-HRCT and HRCT groups included 61 patients (69 ears) and 37 patients (44 ears), respectively. U-HRCT exhibited significantly higher interobserver and intraobserver agreement and stronger concordance with surgical findings for all 10 abnormalities compared with HRCT. It also showed superior diagnostic sensitivity for CMEM (100.0% versus 90.9%; P = .013) and outperformed HRCT in differentiating clinical subtypes (0.774 versus 0.352; P<.001). U-HRCT achieved accuracies exceeding 0.85 in identifying all abnormalities and outperformed HRCT in detecting specific abnormalities including abnormal long process of the incus, lenticular process, abnormal stapes superstructure, stapes footplate fixation, and oval window atresia (P < .05).

Conclusions: Isotropic 0.1-mm U-HRCT significantly outperforms conventional HRCT in diagnosing CMEM, differencing subtypes, and detecting subtle abnormalities, supporting its clinical superiority for precise preoperative evaluation.

Background and purpose: Fetal ventriculomegaly (VM) is common and largely benign when isolated. However, it can occasionally progress to hydrocephalus, a more severe condition associated with increased mortality and neurodevelopmental delay that may require surgical postnatal intervention. Accurate differentiation between VM and hydrocephalus is essential but remains challenging, relying on subjective assessment and limited 2D measurements. Deep learning-based segmentation offers a promising solution for objective and reproducible volumetric analysis. This work presents an artificial intelligence-powered method for segmentation, volume quantification, and classification of the ventricles in fetal brain MRI to predict the need for postnatal intervention.

Materials and methods: This retrospective study included 222 patients with singleton pregnancies. An nnUNet was trained to segment the fetal ventricles on 20 manually segmented, institutional fetal brain MRIs combined with 80 studies from a publicly available data set. The validated model was then applied to 138 normal fetal brain MRIs to generate a normative reference range across a range of gestational ages (18-36 weeks). Finally, it was applied to 64 fetal brains with VM (14 of which required postnatal intervention). Receiver operating characteristic curves and area under curve (AUC) to predict VM and a need for postnatal intervention were calculated.

Results: The nnUNet predicted segmentation of the fetal ventricles in the reference data set were of high quality and accurate (median Dice score: 0.96; interquartile range: 0.93-0.99). A normative reference range of ventricular volumes across gestational ages was developed by using automated segmentation volumes. The optimal threshold for identifying VM was 2 SD from normal with a sensitivity of 92% and a specificity of 93% (AUC 0.97; 95% CI: 0.91-0.98). When normalized to intracranial volume, fetal ventricular volume was higher and subarachnoid volume lower among those who required postnatal intervention (P < .001, P = .003). The optimal threshold for identifying the need for postnatal intervention was 11 SD from normal, with a sensitivity of 86% and a specificity of 100% (AUC: 0.97; 95% CI: 0.86-1.00).

Conclusions: This work introduces a deep learning-based method for fast and accurate quantification of ventricular volumes in fetal brain MRI. A normative reference standard derived by using this method can predict VM and a need for postnatal CSF intervention. Increased ventricular volume is a strong predictor of postnatal intervention.

Background and purpose: Diffuse midline gliomas (DMGs) with concurrent H3K27M and BRAF V600E mutations represent a rare and poorly studied subset of pediatric CNS tumors. While traditionally associated with poor prognosis, recent evidence suggests that mitogen-activated protein kinase (MAPK) pathway alterations may confer improved outcomes in select cases. This study aims to explore the imaging characteristics of H3K27M/BRAF V600E coaltered midline gliomas.

Materials and methods: Eight pediatric patients (6 boys, 2 girls; age range: 3-18 years, mean: 11 years) with H3K27M/BRAFV600E-mutant midline tumors were retrospectively reviewed. Data collected included MR imaging features, histopathologic and molecular data, treatment, and follow-up outcomes.

Results: Of the 8 patients identified, 6 (n=6/8; 75%) tumors were thalamic, with the remainder involving the hypothalamus/optic pathway and cervical spine. Tumors demonstrated heterogeneous histology: pediatric-type low-grade glioma-like (n=3), ganglioglioma-like (n=3), and high-grade glioma-like (n=2). All tumors were midline in location. Thalamic tumors were well-demarcated but demonstrated infiltrative and exophytic components, with frequent involvement of the third ventricle (n=4/6; 66.7%) and internal capsule (n=4/6; 66.7%). Imaging demonstrated heterogeneous T1/T2 signal with coarse calcifications in 5 of the thalamic tumors. Hydrocephalus was present in all patients with thalamic lesions. These tumors demonstrated varied diffusion characteristics with areas of intermediate and reduced diffusivity. Enhancement was present but heterogeneous across tumor types. Both high-grade glioma-like tumors presented with cranial and spinal leptomeningeal metastases.

Conclusions: DMGs harboring both H3K27M and BRAFV600E mutations may represent a distinct subtype, with radiologic, histopathologic, and molecular features that appear different from those of non-MAPK-altered H3K27M DMGs.

Background and purpose: It is important to predict complete obliteration of symptomatic aneurysms after flow diverter (FD) treatment, such as large or giant internal carotid artery aneurysms at the cavernous portion (IC-cav ANs) during the perioperative period for the symptom resolution. Because 3D quantitative color-coding analysis (QCA) is an application of 4D digital subtraction angiography that can evaluate the flow change before and after FD treatment, the aim of this study was to predict the FD treatment outcome for large or giant IC-cav ANs using 3D-QCA during the perioperative period.

Materials and methods: 3D-QCA images were acquired before and after the FD deployment. The ROIs were set in the terminal bifurcation and petrous segment of the internal carotid artery, and the 3D-QCA transit time was measured by comparing the peak contrast intensities in 2 ROIs (Δtransit time). We investigated the change rate in 3D-QCA transit time before and after placing FD (change rate = post-FD Δtransit time/pre-FD Δtransit time). Treatment outcomes were evaluated using the O'Kelly-Marotta (OKM) grading scale with DSA at 6 months after treatment.

Results: The FD was successfully deployed in all 10 cases without coils. The number of OKM grades B, C, and D with DSA at 6 months after treatment was 3, 3, and 4, respectively. The change rate in 3D-QCA transit time was significantly lower in OKM grade D cases compared with grade B and C (57.8% versus 90.1%; P = .01).

Conclusions: 3D-QCA may be effective in predicting the treatment outcome of large or giant IC-cav ANs after FD treatment.

Background and purpose: The telomerase reverse transcriptase (TERT) gene promoter mutation is a crucial factor for identifying an isocitrate dehydrogenase (IDH) wild-type glioblastoma with poor prognosis, and the epidermal growth factor receptor (EGFR) amplification may be a potential prognostic factor. The purpose of this study was to investigate the value of the tumor habitats imaging model on advanced MRI in predicting TERT promoter mutation and EGFR gene amplification phenotype of IDH wild-type glioblastoma.

Materials and methods: One hundred seventy-nine patients with pretreatment conventional MRI, DWI, and DSC-PWI were included. The data were divided into the training set (n=112), test set (n=29), and time-independent validation set (n=38). Based on the ADC and CBV map, the solid tumor area was split into several habitat subregions using the k-means clustering algorithm (hypovascular hypercellular area, hypervascular area, and hypovascular hypocellular area). In the training set, TERT promoter mutation and EGFR gene amplification phenotype prediction models were constructed using the random forest method. The reliability of prediction models was validated in the test and the time-independent validation sets. Receiver operating characteristic (ROC) curve analysis, calibration curve, and decision curve analysis (DCA) were used.

Results: The area under the curve (AUC) of the training, test, and validation sets of the TERT promoter prediction model was 0.877, 0.783, and 0.796, respectively. The accuracy of the TERT promoter prediction model was 82.1%, 75.9%, and 76.3%, respectively. The AUCs of the 3 sets for the EGFR gene amplification status prediction model were 0.877, 0.784, and 0.878, respectively. The accuracy of the EGFR gene amplification status prediction model was 79.5%, 75.9%, and 89.5%, respectively. Moreover, the prediction probability of these models was in good agreement with the actual result.

Conclusions: The tumor habitat imaging model based on advanced MRI was useful for accurately predicting TERT promoter mutation and EGFR amplification status in IDH wild-type glioblastoma.