Neuroradiology最新文献

Aims: To test utility of diffusion MRI-derived indices in carotid endarterectomy (CEA), change of diffusion tensor imaging (DTI) metrics, cerebral white matter (WM) volumes were evaluated and predictors of overall mortality determined.

Methods: Prospectively enrolled participants had preoperative, immediate and late postoperative DTI after CEA. WM volumes, DTI metrics (fractional anisotropy, FA; axial, radial, mean diffusivities; AD, RD, MD, respectively) were calculated for the index/contralateral hemispheres at all time points. Temporal changes, predictors of log₂-transformed WM volumes, DTI values were analyzed using linear mixed model. Uni- and multivariable Cox proportional hazards models were used to identify predictors of mortality.

Results: 60 subjects (57% male, 69.5 ± 7.2years) were included. Significantly increased AD and MD was observed in both hemispheres comparing the preoperative and immediate postoperative DTI metrics (index AD: β = 0.02 [95%CI:0.01,0.02], p < 0.001; index MD: β = 0.02 [95%CI:0.01,0.03], p < 0.001; contralateral AD: β = 0.01 [95%CI:0.01,0.02], p = 0.001; contralateral MD: β = 0.02 [95%CI:0.01,0.03], p = 0.003). The index MD decreased (β = 0.01 [95%CI:0.01,0.001], p = 0.04), bilateral WM volumes (index WM: β = 0.04 [95%CI:0.02,0.07], p < 0.001; contralateral WM: β = 0.05 [95%CI:0.03,0.07], p < 0.001) decreased significantly between the immediate and late postoperative scans. Postoperative contralateral FA correlated significantly with lower mortality (HR = 0.001 [95%CI:0.001,0.19], p = 0.02); postoperative contralateral RD (HR = 3.74 × 10⁴ [95%CI:1.62,8.60 × 10⁸], p = 0.04) and MD (HR = 1.19 × 10⁵ [95%CI:1.03,1.37 × 10¹⁰], p = 0.049) were significant predictors of mortality.

Conclusion: The increase of various DTI metrics from pre-to-postoperative may be indicative of microstructural deterioration following CEA. Temporal changes between the immediate and late postoperative scans suggest, however, reversal of detrimental WM changes and clearance of presumed subclinical WM edema. Our results also imply, that preserved cerebral properties are protective after CEA.

Purpose: We aimed to validate a clinically available artificial intelligence (AI) model to assist general radiologists in the detection of intracranial aneurysm (IA) in a multi-reader multi-case (MRMC) study, and to explore its performance in routine clinical settings.

Methods: Two distinct cohorts of head CT angiography (CTA) data were assembled to validate an AI model. Cohort 1, comprising gold-standard consecutive CTA cases, was used in an MRMC study involving six board-certified general radiologists. Cohort 2, representing clinical CTA cases, was used to simulate a routine clinical setting. Following these evaluations, an algorithmic audit was conducted to identify any unusual or unexpected behaviors exhibited by the model.

Results: Cohort 1 consisted of 131 CTA cases, while Cohort 2 included 515 CTA cases. In the MRMC study, the AI-assisted strategy demonstrated a significant improvement in aneurysm diagnostic performance, with the area under the receiver operating characteristic curve increasing from 0.815 (95%CI: 0.754-0.875) to 0.875 (95%CI: 0.831-0.921; p = 0.008). In the AI-based first-reader study, 60.4% of the CTA cases were identified as negative by the AI, with a high negative predictive value of 0.994 (95%CI: 0.977-0.999). The algorithmic audit highlighted two issues for improvement: the accurate detection of tiny aneurysms and the effective exclusion of false-positive lesions.

Conclusion: This study highlights the clinical utility of a high-performance AI model in detecting IAs, significantly improving general radiologists' diagnostic performance with the potential to reduce their workload in routine clinical practice. The algorithmic audit offers insights to guide the development and validation of future AI models.

Introduction: This study investigates the influence of carotid artery elongation on neurovascular intervention and outcome in acute stroke treatments proposing an easily assessable imaging marker for carotid elongation.

Methods: 118 patients who underwent mechanical thrombectomy for middle cerebral artery occlusions were included. The carotid elongation ratio (CER), center-line artery length to scan's Z-axis, was measured on the affected side in CT-angiographies. Full and partial correlations of CER with periprocedural times, complications and outcome were computed. Multivariate logistic regression, including comorbidities, for prediction of dichotomized mRS outcome after 3 months was performed.

Results: CER showed no significant correlation with recanalization success. Weak, outlier-driven correlation was found with recanalization time (p = 0.021, cor = 0.2). Weak correlations were found with improvement of NIHSS score at discharge and mRS score after 3 months (p = 0.023 and p = 0.031, each rho=-0.2). There was moderate correlation with NIHSS score at discharge (p = 0.001, rho = 0.3). Patients with favorable outcomes (mRS 0-2) exhibited lower CER (p = 0.012). Partial correlations of CER with favorable outcomes were observed after correcting for age, sex and cardiovascular risk factors (cor = 0.2, p = 0.048). Multivariate analysis (Nagelkerke's R2 = 0.42) identified NIHSS score at admission, diabetes, hypertension and intervention time as significant factors for predicting outcome at 3 month, while CER showed the highest log Odd's (2.97).

Conclusion: Correlations between CER and clinical improvement suggest that carotid elongation might be a risk factor for poorer outcome without relevant effect on endovascular treatment and should not guide treatment decisions. Further studies should consider carotid elongation as an individual neurovascular risk factor, independent of hypertension.

Background: Subarachnoid hyperdensity (SAH) after endovascular thrombectomy is a well-known phenomenon. Nevertheless, the clinical significance and natural history of this phenomenon is not well described. In addition, we test previously postulated hypotheses of distal occlusions sites and antithrombotic use to SAH prevalence and extent.

Methods: We performed a retrospective analysis of all patients presenting with acute stroke and treated by endovascular thrmbectomy in our tertiary center January 2016 and February 2021. Only patients who underwent CT scan of the brain within 24 h after procedure were included.

Results: 394 patients were included in this study. SAH after EVT was evident on CT in18.3% of those. Most of these (10.7%), had non-resolving hyperdensity (persistent SAH) on follow up imaging. A minority (2.6%) had resolving hyperdensity (transient SAH). Only 2% had a combination of subarachnoid hyperdensity and intracerebral hemorrhage (SAH + ICH). Transient and persistent SAH were associated with good functional and imaging outcomes as compared to SAH + ICH patients. Older age, large infarct size, stentretriever use and partial recanalization were correlated with SAH + ICH. Distal occlusions and distal vessel angulations resulting in higher traction potential were more prevalent in persistent SAH group. Higher number of thrombectomy passes was correlated with the extent of persistent SAH. Transient SAH group did not show statistically significant demographic or procedural trends.

Discussion: We propose therefore a distinct classification of the post thrombectomy SAH subtypes and discuss the putative pathophysiological mechanisms of the three distinct phenomena and their predictive factors.

Introduction: Residual dizziness (RD) is common in patients with benign paroxysmal positional vertigo (BPPV) after successful canalith repositioning procedures. This study aimed to investigate the therapeutic effects of vestibular rehabilitation (VR) on BPPV patients experiencing RD, and to explore the impact of VR on functional connectivity (FC), specifically focusing on the bilateral parietal operculum (OP) cortex.

Methods: Seventy patients with RD were randomly assigned to either a four-week VR group or a control group that received no treatment. Assessments included the dizziness Visual Analog Scale (VAS), Dizziness Handicap Inventory (DHI), Hamilton Anxiety/Depression Scale (HAMA/HAMD), and resting-state functional magnetic resonance imaging.

Results: The VR group exhibited a significant decline in scores on VAS, DHI, HAMA and HAMD following training (all p < 0.05). Furthermore, the VR group demonstrated increased FC between the left OP and both the left precuneus and left middle frontal gyrus (MFG), and between the right OP and the right MFG (voxel-level p < 0.001; cluster-level p < 0.05, FDR corrected). Additionally, these changes in FC were found to correlate with clinical features, including scores on HAMA (p = 0.012, r =  - 0.513) and DHI (p = 0.022, r =  - 0.475) after the intervention.

Conclusion: This study demonstrated the therapeutic effects of VR in alleviating RD and emotional disorders, as well as in improving overall quality of life. Notably, these positive outcomes might be associated with increased FC between brain regions involved in mood regulation and vestibular processing. Our findings offer novel neuroimaging evidence that supports the hypothesis that VR facilitates dynamic vestibular compensation.

Objective: Young migraine patients often present with white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI). This study aimed to analyze whether synthetic (Syn) T2-FLAIR and Syn double inversion recovery (DIR) can reveal WMHs more clearly and sensitively than conventional T2-FLAIR.

Materials and methods: Conventional MRI and Syn MRI data from 50 young migraine patients were analyzed prospectively. WMHs in each anatomical region (periventricular, deep white matter, and juxtacortical) were recorded separately. The differences in the clarity of lesion boundaries and the number of lesions displayed in the three sequences in the same anatomical region were analyzed.

Results: A total of 80 (periventricular area, 15; deep white matter, 31; juxtacortical area, 34), 163 (17, 50, 96), and 134 (18, 42, 74) lesions were observed with conventional T2-FLAIR, Syn T2-FLAIR, and Syn DIR, respectively. Syn T2-FLAIR and Syn DIR can show lesions more clearly than conventional T2-FLAIR (all P < 0.001). There was no significant difference in the number of lesions observed in the periventricular white matter among the three sequences (P = 0.159, 0.083, 0.322). Syn T2-FLAIR and Syn DIR can detect more lesions in the deep white matter than conventional T2-FLAIR (P < 0.001, P = 0.006). Syn T2-FLAIR revealed more lesions in the juxtacortical white matter than Syn DIR and conventional T2-FLAIR imaging (all P < 0.001), and conventional T2-FLAIR revealed the fewest lesions (P < 0.001).

Conclusion: Syn T2-FLAIR and Syn DIR sequences can clearly and sensitively detect WMHs, especially in deep and juxtacortical white matter areas.

Purpose: Various angiographic assessment scales have been used to report the results of endovascular treatment with the WEB device. We aimed to review the use and reliability of these scales.

Methods: We systematically reviewed studies reporting angiographic outcomes of WEB-treated aneurysms from January 2010 to May 2023. We identified the studies that reported the reliability of the various scales. Data from eligible studies were extracted and evaluated by two independent reviewers, with discrepancies resolved by a third reviewer.

Findings: The review identified 138 studies that used 12 different occlusion scales. The non-specific Raymond-Roy occlusion classification (RROC) was most commonly used (94/138 (68%)), followed by the Bicêtre Occlusion Scale Score (BOSS; 21/138 (15%)) and the Web Occlusion Scale (WOS; 16/138 (12%)), both specifically adapted to the WEB. Six reliability studies were identified, which included 16-30 cases evaluated by few (2-7) raters. Studies were too heterogenous to proceed with a meta-analysis. Substantial agreement in reporting angiographic results was shown in one study using the WOS (K = 0.70; 0.64-0.75), and one using the BOSS (K = 0.82; 0.68-0.96), but only when categories were dichotomized as complete versus incomplete occlusion. Most classifications can be translated into the RROC, allowing comparisons with other devices and treatment modalities. The RROC reached substantial agreement, but only between 2 raters in a small 26-patient study (k = 0.69; 0.46-0.93).

Conclusion: More agreement studies are needed to validate the reliability of angiographic outcome scales that can be used to compare WEB with other endovascular or surgical treatments.

Introduction: Mechanical thrombectomy (MT) efficacy in medium vessel occlusion (MeVO) stroke, particularly in patients with low Alberta Stroke Program Early Computed Tomography Score (ASPECTS), remains less explored.

Methods: This retrospective study analyzed data from 443 AIS patients treated with MT for MeVO and low ASPECTS (4-7) at 37 centers across North America, Asia, and Europe, from September 2017 to July 2021. Patients were categorized into ASPECTS of 4-5 and 6-7.

Results: Of 443 patients, 51 (12%) had ASPECTS of 4-5, and 392 (88%) had scores of 6-7. The median age was 65 years (IQR: 46-79), with a balanced sex distribution between the groups. The most common site of initial occlusion was M2 branch in both groups (92% in ASPECTS 4-5 and 85% in ASPECTS 6-7) (p = 0.68). The ASPECTS 4-5 group had lower TICI 2c-3 achievement (31% vs. 55%, p = 0.002) and poorer functional outcomes (mRS 0-1 at 90 days: 12% vs. 29%, p = 0.03) compared to the ASPECTS 6-7 group. Intracranial hemorrhagic complications were higher in the ASPECTS 4-5 group (69% vs. 47%, p = 0.007). Multivariable analysis revealed ASPECTS 6-7 to be associated with higher odds of TICI 2c-3 (OR: 2.5; CI: 1.28 to 4.89, p = 0.007) and lower odds of intracranial hemorrhagic complications (OR: 0.4; CI: 0.19 to 0.81, p = 0.012).

Conclusion: MT may be associated with improved outcomes in patients with moderate-to-low ASPECTS (6-7), though the lack of a control group limits definitive conclusions about its effectiveness. In patients with very low ASPECTS (4-5), higher rates of hemorrhagic complications and poorer outcomes were observed, but this does not necessarily preclude the use of MT. These findings highlight the need for further research and careful patient selection.

Purpose: The time-intensive nature of acquiring 3D T1-weighted MRI and analyzing brain volumetry limits quantitative evaluation of brain atrophy. We explore the feasibility and reliability of deep learning-based accelerated MRI scans for brain volumetry.

Methods: This retrospective study collected 3D T1-weighted data using 3T from 42 participants for the simulated acceleration dataset and 48 for the validation dataset. The simulated acceleration dataset consists of three sets at different simulated acceleration levels (Simul-Accel) corresponding to level 1 (65% undersampling), 2 (70%), and 3 (75%). These images were then subjected to deep learning-based reconstruction (Simul-Accel-DL). Conventional images (Conv) without acceleration and DL were set as the reference. In the validation dataset, DICOM images were collected from Conv and accelerated scan with DL-based reconstruction (Accel-DL). The image quality of Simul-Accel-DL was evaluated using quantitative error metrics. Volumetric measurements were evaluated using intraclass correlation coefficients (ICCs) and linear regression analysis in both datasets. The volumes were estimated by two software, NeuroQuant and DeepBrain.

Results: Simul-Accel-DL across all acceleration levels revealed comparable or better error metrics than Simul-Accel. In the simulated acceleration dataset, ICCs between Conv and Simul-Accel-DL in all ROIs exceeded 0.90 for volumes and 0.77 for normative percentiles at all acceleration levels. In the validation dataset, ICCs for volumes > 0.96, ICCs for normative percentiles > 0.89, and R² > 0.93 at all ROIs except pallidum demonstrated good agreement in both software.

Conclusion: DL-based reconstruction achieves clinical feasibility of 3D T1 brain volumetric MRI by up to 75% acceleration relative to full-sampled acquisition.