AJNR. American journal of neuroradiology最新文献

Background and purpose: Whether differences in the O⁶-methylguanine-DNA methyltransferase (MGMT) promoter methylation status of glioblastoma (GBM) are reflected in MRI markers remains largely unknown. In this work, we analyze the ADC in the perienhancing infiltration zone of GBM according to the corresponding MGMT status by using a novel distance-resolved 3D evaluation.

Materials and methods: One hundred one patients with IDH wild-type GBM were retrospectively analyzed. GBM was segmented in 3D with deep learning. Tissue with FLAIR hyperintensity around the contrast-enhanced tumor was divided into concentric distance-resolved subvolumes. Mean ADC was calculated for the 3D tumor core and for the distance-resolved volumes around the core. Differences in group mean ADC between patients with MGMT promoter methylated (mMGMT, n = 43) and MGMT promoter unmethylated (uMGMT, n = 58) GBM was analyzed with Wilcoxon signed rank test.

Results: For both mMGMT and uMGMT GBM, mean ADC values around the tumor core significantly increased as a function of distance from the core toward the periphery of the perienhancing FLAIR hyperintensity (approximately 10% increase within 5 voxels with P < 001). While group mean ADC in the tumor core was not significantly different, the distance-resolved ADC profile around the core was approximately 10% higher in mMGMT than in uMGMT GBM (P < 10^-8 at 5 voxel distance from the tumor core).

Conclusions: Distance-resolved volumetric ADC analysis around the tumor core reveals tissue signatures of GBM imperceptible to the human eye on conventional MRI. The different ADC profiles around the core suggest epigenetically influenced differences in perienhancing tissue characteristics between mMGMT and uMGMT GBM.

Background and purpose: It is estimated that 18%-30% of patients with concussion experience symptoms lasting more than 1 month, known as persistent post-concussion symptoms (PPCS). Symptoms can be debilitating, and include headache, dizziness, nausea, problems with memory and concentration, sleep and mood disruption, and exercise intolerance. Previous studies have used quantitative susceptibility mapping (QSM) to show altered tissue susceptibility levels in adults acutely following concussion, however this finding has yet to be investigated in participants with PPCS.

Materials and methods: In this exploratory case-controlled study, we measured tissue susceptibility using QSM in 24 participants with PPCS after mild traumatic brain injury (mTBI) and 23 healthy controls with no history of concussion. We compute tissue susceptibility for 7 white matter tracts and 3 deep gray matter regions and compare tissue susceptibility between groups using ANCOVA models controlling for age and sex. We also assess the relationship between regional tissue susceptibility and symptoms.

Results: There were no significant differences between tissue susceptibility in participants with PPCS compared with control subjects in any of the evaluated regions. However, we show lower tissue susceptibility across 4 white matter tracts was generally associated with worse symptoms in the PPCS group. Specifically, we saw relationships between white matter susceptibility and headache (p = .006), time since injury (p = .03), depressive symptoms (p = .021), and daytime fatigue (p = .01) in participants with PPCS.

Conclusions: These results provide evidence in support of persistent changes in the brain months to years after injury and highlight the need to further understand the pathophysiology of PPCS, to determine effective prevention and treatment options.

Spinal CSF leaks from dural tears or CSF-venous fistulas are the most common causes of spontaneous intracranial hypotension. Rarely, CSF leaks have also been associated with vascular malformations, which have primarily been discussed in case reports or small series. In this clinical report, we report the clinical features, imaging findings, and treatment of 6 children and adults with CSF leaks associated with vascular malformations in the spine and skull base depicted on CT myelography and cisternography.

Background and purpose: Even though glioblastoma (GB) and brain metastases (BM) can be differentiated using radiomics, it remains unclear if the model performance may vary based on the contrast-enhanced sequence used. Our aim was to evaluate the radiomics-based model performance for differentiation between GB and brain metastases BM using MPRAGE and volumetric interpolated breath-hold examination (VIBE) T1-contrast-enhanced sequence.

Materials and methods: T1 contrast-enhanced (T1-CE) MPRAGE and VIBE sequences acquired in 108 patients (31 GBs and 77 BM) during the same MRI session were retrospectively evaluated. After standardized image preprocessing and segmentation, radiomics features were extracted from necrotic and enhancing tumor components. Pearson correlation analysis of radiomics features from tumor subcomponents was also performed. A total of 90 machine learning pipelines were evaluated using a 5-fold cross-validation. Performance was measured by mean area under the curve (AUC)-receiver operating characteristic (ROC), log loss, and Brier scores.

Results: A feature-wise comparison showed that the radiomics features between sequences were strongly correlated, with the highest correlation for shape-based features. The mean AUC across the top 10 pipelines ranged between 0.851 and 0.890 with T1-CE MPRAGE and between 0.869 and 0.907 with the T1-CE VIBE sequence. The top-performing models for the MPRAGE sequence commonly used support vector machines, while those for the VIBE sequence used either support vector machines or random forest. Common feature-reduction methods for top-performing models included linear combination filter and least absolute shrinkage and selection operator for both sequences. For the same machine learning feature-reduction pipeline, model performances were comparable (AUC-ROC difference range, -0.078-0.046).

Conclusions: Radiomics features derived from T1-CE MPRAGE and VIBE sequences are strongly correlated and may have similar overall classification performance for differentiating GB from BM.

Background: Intrameatal vascular loops (IVL) entering the internal auditory meatus and neurovascular contact (NVC) with the vestibulocochlear nerve (cranial nerve [CN] VIII) have been proposed to have a relationship with audiovestibular symptoms.

Purpose: This systematic review and meta-analysis aimed to determine whether the presence of IVLs and CN VIII NVC on MRI is associated with tinnitus, sensorineural hearing loss (SNHL), or vertigo and any specific subtypes.

Data sources: All studies comparing the presence of IVL or CN VIII NVC in ears with these audiovestibular symptoms and controls were identified through MEDLINE, EMBASE, the Web of Science Core Collection, Scopus, and the Cochrane Register of Controlled Trials databases.

Study selection: Sixteen studies and 3455 ears (1526 symptomatic ears and 1929 control ears) were included.

Data analysis: Meta-analysis was performed using a bivariate random effects model. Pooled ORs were calculated, and heterogeneity was evaluated with the Cochran Q test with statistical significance defined as P < .05.

Data synthesis: There was no significant association between the presence of undefined tinnitus or SNHL and IVL (OR, 0.90; 95% CI, 0.47-1.70; OR, 0.67; 95% CI, 0.36-1.25) or CN VIII NVC (OR, 1.15; 95% CI, 0.68-1.95; OR, 0.89; 95% CI, 0.33-2.40). However, the subgroup of sudden onset SNHL was associated with IVL (OR, 1.34; 95% CI, 1.04-1.73) (P = .02). There was no significant difference in the prevalence of IVL (OR, 0.97; 95% CI 0.64-1.48) or CN VIII NVC (OR, 0.99; 95% CI, 0.42-2.32) between ears with undefined vertigo and control ears. However, there was an association between the presence of CN VIII NVC and the specific diagnosis of vestibular paroxysmia (OR, 13.19; 95% CI, 2.09-83.16) (P = .006).

Limitations: Our meta-analysis is limited by selection bias, the small number of eligible studies, and moderate heterogeneity.

Conclusions: IVL or CN VIII NVC on MRI is unrelated to symptoms of undefined tinnitus, SNHL, and vertigo. However, CN VIII NVC is associated with vestibular paroxysmia, while IVL is associated with sudden onset SNHL.

Background and purpose: Changes in perivascular fat density (PFD) and its association with inflammation have been topics of interest in both atherosclerotic and nonatherosclerotic vasculopathies. The objective of this study was to assess the PFD in patients with spontaneous internal carotid artery dissection (SICAD) or carotid atherosclerotic plaque, with and without intraplaque hemorrhage (IPH).

Materials and methods: A cross-sectional retrospective bicentric analysis of 130 patients (30 with SICAD and 100 with carotid atherosclerotic plaque) who underwent CT angiography was performed. Among the subjects with atherosclerotic plaque, 36 showed the presence of IPH. PFD analysis was performed by 2 radiologists who placed 2 ROIs to identify the perivascular fat tissue attenuation. The Mann-Whitney U test was conducted to evaluate the difference between patient cohorts.

Results: Carotid arteries with SICAD and IPH demonstrated an average PFD of -68.97 HU (95% CI, -72.11 to -65.82 HU) and -69.97 HU (95% CI, -73.00 to -66.95 HU), respectively, in comparison with patients without IPH, who showed an average PFD -77.11 HU (95% CI,-78.78 to -75.44 HU) (P < .001 for both). Conversely, no significant differences were found between patients with SICAD and those with carotid plaque with IPH (P = .324).

Conclusions: The average PFDs in patients with SICAD and carotid atherosclerosis plaque with IPH were similar and higher than those in patients with carotid plaque without IPH. This finding suggests a shared pathologic inflammatory mechanism in these 2 conditions. Studies comparing pathologic specimens directly with radiologic images may be needed to confirm this indirect hypothesis.

Background and purpose: Symptoms indistinguishable from behavioral-variant frontotemporal dementia (bvFTD) can develop in patients with spontaneous intracranial hypotension associated with severe brain sagging. An underlying spinal CSF leak can be identified in only a minority of these patients and the success rate of nondirected treatments, such as epidural blood patching and dural reduction surgery, is low. The disability associated with bvFTD sagging brain syndrome is high and, because of the importance of the venous system in the pathophysiology of CSF leaks in general, we have investigated the systemic venous circulation in those patients with recalcitrant symptoms.

Materials and methods: We reviewed the medical records and imaging studies of 21 consecutive patients with bvFTD sagging brain syndrome in whom no spinal CSF leak could be found and who underwent imaging of the systemic venous circulation (MR- or CT-venography). An SIH Disability Assessment Score (SIHDAS) questionnaire was completed to assess the severity of the symptoms.

Results: The mean age of the 3 women and 18 men was 50 years (range, 26-68 years). Seven patients were found to have venous stenosis. Endovascular stent placement of moderate to high-grade azygos vein stenosis in 3 patients resulted in prompt and remarkable improvement of symptoms in 2 patients (SIHDAS: very severe disability to no or mild disability) and mild improvement in 1 patient (SIHDAS: very severe disability to severe disability). Treatment of internal jugular vein and inferior vena cava stenosis in 2 patients each did not result in any improvement of symptoms. Endovascular (5 patients) or surgical (2 patients) interruption of multiple epidural spinal venous pathways did not result in any clinical improvement.

Conclusions: The azygos vein is the main conduit between the spinal CSF space and the systemic venous circulation and this study demonstrates that isolated azygos vein stenosis may be a cause of spinal CSF loss and sagging brain syndrome. In this study, the yield of finding a clinically important treatable venous lesion among patients with recalcitrant bvFTD sagging brain syndrome was relatively low (15%). However, high quality and safe noninvasive imaging of the systemic venous system is available, eg, MR-venography, and should be considered for those patients who have exhausted treatments for this devastating condition, focusing on the azygos system.

Background and purpose: The efficacy and safety of endovascular thrombectomy (EVT) for elderly patients with basilar artery occlusion (BAO) stroke is unclear. The purpose of this study is to investigate the safety and efficacy of EVT for elderly BAO stroke patients.

Materials and methods: This was an explorative retrospective analysis of the 2016-21 National Inpatient Sample in the United States. Elderly patients with BAO stroke (80 years of age or older) with an NIHSS score of at least 5 were included. Primary outcome was discharge home. Secondary outcomes included in-hospital mortality and intracranial hemorrhage (ICH). Outcomes were compared between patients treated with EVT and those treated with medical management (MM) alone. Propensity score matching (PSM) was performed to control confounders. Subgroup analyses were conducted for patients who did and did not receive IV thrombolysis (IVT).

Results: We identified 2520 elderly patients with BAO stroke; 830 received EVT and 1690 received MM alone. After PSM, 1115 patients and 715 patients remained in the MM and EVT groups, respectively. Compared with PSM controls, EVT was not significantly associated with different rates of home discharge (17.5% versus 12.2%; OR, 1.36 [95% CI, 0.76-2.44], P = .30) or in-hospital mortality (31.5% versus 32.9%; OR, 1.00 [95% CI, 0.63-1.60], P = .99), but it was significantly associated with higher rates of ICH (18.2% versus 7.3%; OR, 2.69 [95% CI, 1.41-5.15], P = .003). Among patients who did not receive IVT, EVT was significantly associated with higher rates of home discharge (21.5% versus 11.5%; OR, 1.93 [95% CI, 1.02-3.66], P = .044), whereas EVT was not significantly associated with a different rate of home discharge among those treated with IVT (5.6% versus 15.0%; OR, 0.28 [95% CI, 0.05-1.46], P = .13). Interaction analysis revealed that IVT was a negative modulator of the positive association of EVTs with home discharge (interaction P = .031).

Conclusions: EVT was not significantly associated with more favorable hospitalization outcomes for elderly patients with BAO stroke, and it was significantly associated with an increased risk of ICH. EVT may be an effective treatment for patients who did not receive IVT.

Background and purpose: Normalized relative cerebral blood volume (nrCBV) and percentage of signal recovery (PSR) computed from dynamic susceptibility contrast (DSC) perfusion imaging are useful biomarkers for differential diagnosis and treatment response assessment in brain tumors. However, their measurements are dependent on DSC acquisition factors, and CBV-optimized protocols technically differ from PSR-optimized protocols. This study aimed to generate "synthetic" DSC data with adjustable synthetic acquisition parameters using dual-echo gradient-echo (GE) DSC datasets extracted from dynamic spin-and-gradient-echo echoplanar imaging (dynamic SAGE-EPI). Synthetic DSC was aimed at: 1) simultaneously create nrCBV and PSR maps using optimal sequence parameters, 2) compare DSC datasets with heterogeneous external cohorts, and 3) assess the impact of acquisition factors on DSC metrics.

Materials and methods: Thirty-eight patients with contrast-enhancing brain tumors were prospectively imaged with dynamic SAGE-EPI during a non-preloaded single-dose contrast injection and included in this cross-sectional study. Multiple synthetic DSC curves with desired pulse sequence parameters were generated using the Bloch equations applied to the dual-echo GE data extracted from dynamic SAGE-EPI datasets, with or without optional preload simulation.

Results: Dynamic SAGE-EPI allowed for simultaneous generation of CBV-optimized and PSR-optimized DSC datasets with a single contrast injection, while PSR computation from guideline-compliant CBV-optimized protocols resulted in rank variations within the cohort (Spearman's ρ = 0.83-0.89, i.e. 31%-21% rank variation). Treatment-naïve glioblastoma exhibited lower parameter-matched PSR compared to the external cohorts of treatment-naïve primary CNS lymphomas (PCNSL) (p<0.0001), supporting a role of synthetic DSC for multicenter comparisons. Acquisition factors highly impacted PSR, and nrCBV without leakage correction also showed parameter-dependence, although less pronounced. However, this dependence was remarkably mitigated by post-hoc leakage correction.

Conclusions: Dynamic SAGE-EPI allows for simultaneous generation of CBV-optimized and PSR-optimized DSC data with one acquisition and a single contrast injection, facilitating the use of a single perfusion protocol for all DSC applications. This approach may also be useful for comparisons of perfusion metrics across heterogeneous multicenter datasets, as it facilitates post-hoc harmonization.