AJNR. American journal of neuroradiology最新文献

Background and purpose: Precise and individualized targeting of the ventral intermediate thalamic nucleus for the MR-guided focused ultrasound is crucial for enhancing treatment efficacy and avoiding undesirable side effects. In this study, we tested the hypothesis that the spatial relationships between Thalamus Optimized Multi Atlas Segmentation derived segmentations and the post-focused ultrasound lesion can predict post-operative side effects in patients treated with MR-guided focused ultrasound.

Materials and methods: We retrospectively analyzed 30 patients (essential tremor, n = 26; tremor-dominant Parkinson's disease, n = 4) who underwent unilateral ventral intermediate thalamic nucleus focused ultrasound treatment. We created ROIs of coordinate-based indirect treatment target, focused ultrasound-induced lesion, and thalamus and ventral intermediate thalamic nucleus segmentations. We extracted imaging features including 1) focused ultrasound-induced lesion volumes, 2) overlap between lesions and thalamus and ventral intermediate thalamic nucleus segmentations, 3) distance between lesions and ventral intermediate thalamic nucleus segmentation and 4) distance between lesions and the indirect standard target. These imaging features were compared between patients with and without post-operative gait/balance side effects using Wilcoxon rank-sum test. Multivariate prediction models of side effects based on the imaging features were evaluated using the receiver operating characteristic analyses.

Results: Patients with self-reported gait/balance side effects had a significantly larger extent of focused ultrasound-induced edema, a smaller fraction of the lesion within the ventral intermediate thalamic nucleus segmentation, a larger fraction of the off-target lesion outside the thalamus segmentation, a more inferior centroid of the lesion from the ventral intermediate thalamic nucleus segmentation, and a larger distance between the centroid of the lesion and ventral intermediate thalamic nucleus segmentation (p < 0.05). Similar results were found for exam-based side effects. Multivariate regression models based on the imaging features achieved areas under the curve of 0.99 (95% CI: 0.88 to 1.00) and 0.96 (95% CI: 0.73 to 1.00) for predicting self-reported and exam-based side effects, respectively.

Conclusions: Thalamus Optimized Multi Atlas Segmentation-based patient-specific segmentation of the ventral intermediate thalamic nucleus can predict post-operative side effects, which has implications for aiding the direct targeting of MR-guided focused ultrasound and reducing side effects.

CT-guided injection and radiofrequency ablation (RFA) of the C2 dorsal root ganglion (DRG) is a safe and effective treatment for cervicogenic headache arising from C1-C2 joint arthritis. The C2 nerve root is unique in that it lacks a motor component; RFA can be performed with pain relief in exchange for occipital numbness. This video article outlines the imaging anatomy and technical considerations of this procedure.

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: Anatomically adapted cochlear implantation and efficient postoperative cochlear implant-fitting strategies benefit from reliable and highly detailed imaging techniques. Since image quality in CT is related to the applied radiation dose, this study aimed to evaluate low-dose cochlear imaging with a photon-counting detector by investigating the accuracy of pre- and postoperative cochlear analysis.

Materials and methods: Photon-counting CT images of 10 temporal bone specimens were acquired with 3 different radiation dose levels (regular dose: 27.1 mGy, low dose: 4.81 mGy, and ultra-low dose: 3.43 mGy) before and after cochlear implant electrode carrier insertion. A clinical scan protocol was used with a tube potential of 120 kV in ultra-high-resolution scan mode (detector collimation 120 × 0.2 mm). The accuracy of cochlear duct length measurements for the organ of Corti and electrode contact determination was investigated for all applied settings by 2 independent otosurgeons.

Results: No substantial differences were ascertained between photon-counting CT scans performed with standard dose and dedicated low-dose imaging regarding the accuracy of neither pre- and postoperative cochlear analysis nor postoperative cochlear implant electrode analysis. Radiation dose reduction of 82.3% (low dose) and 87.3% (ultra-low dose) could be realized compared with the clinical standard protocol.

Conclusions: Ultra-high-resolution cochlear imaging is feasible with very low radiation exposure when using a first-generation photon-counting CT in combination with dedicated low-dose protocols. The accuracy of pre- and postoperative cochlear analysis with the applied dose reduction settings was comparable with a clinical regular-dose protocol.

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.

Background and purpose: The quality of resting-state fMRI (rs-fMRI) under anesthesia is variable and there are no guidelines on optimal image acquisition or anesthesia protocol. We aim to identify the factors that may lead to compromised clinical rs-fMRI under anesthesia.

Materials and methods: In this cross-sectional study, we analyzed clinical rs-fMRI data acquired under anesthesia from 2009-2023 at Massachusetts General Hospital. Independent component analysis-driven resting-state networks (RSNs) of each patient were evaluated qualitatively and quantitatively and grouped as robust or weak. Overall networks were evaluated by using the qualitative method, and motor and language networks were evaluated by using the quantitative method. RSN robustness was analyzed in 4 outcome categories: overall, combined motor-language, individual motor, and language networks. Predictor variables included rs-fMRI acquisition parameters, anesthesia medications, underlying brain structural abnormalities, age, and sex. Logistic regression was used to examine the effect of the study variables on RSN robustness.

Results: Sixty-nine patients were identified. With qualitative assessment, 40 had robust and 29 had weak overall RSN. Quantitatively, 45 patients had robust, while 24 had weak motor-language networks. Among all the predictor variables, only sevoflurane significantly contributed to the outcomes, with sevoflurane administration reducing the odds of having robust RSN in overall (OR = 0.2, 95% CI = 0.05-0.79, P = .02), motor-language (OR = 0.18, 95% CI = 0.04-0.80, P = .02), and individual motor (OR = 0.1, 95% CI = 0.02-0.64, P = .02) categories. Individual language network robustness was not associated with the tested predictor variables.

Conclusions: Sevoflurane anesthesia may compromise the visibility of fMRI RSN, particularly impacting motor networks. This finding suggests that the type of anesthesia is a critical factor in rs-fMRI quality. We did not observe the association of the MR acquisition technique or underlying structural abnormality with the RSN robustness.

Background and purpose: Flat panel conebeam CT (CBCT) is essential for detecting hemorrhagic complications during neuroendovascular treatments. Despite its superior image quality and trajectory over conventional CBCT (circular scan), the dual-axis butterfly scan has a slightly higher radiation dose relative to conventional CBCT. This study evaluates the image quality in dose-reduction mode to uncover the appropriate radiation dose for the butterfly scan.

Materials and methods: We prospectively included patients who were scheduled for neuroendovascular treatment and underwent conventional CBCT and the dose-reduction mode of the butterfly scan. Two reduced radiation dose modes were used for the butterfly scan: medium-dose butterfly scan (70% of the original dose, 45 mGy) or low-dose butterfly scan (50% of the original dose, 30 mGy). The enrolled patients were assigned alternately to undergo either the medium- or low-dose butterfly scan. We evaluated and compared artifacts, contrast, and discrimination of the corticomedullary junction between conventional CBCT and one of the dose-reduction modes of the butterfly scan, with a 5-point scale scoring system.

Results: Twenty patients were enrolled in each of the medium- and low-dose groups, totaling 40 patients. Compared with conventional CBCT, the medium-dose butterfly group exhibited reduced artifacts, enhanced contrast, and corticomedullary junction discrimination (except in the occipital lobe). While the low-dose butterfly group exhibited markedly reduced artifacts and improved contrast (except in the occipital lobe), a significant improvement in corticomedullary junction discrimination was not observed.

Conclusions: Even with dose reduction, the specialized trajectory of the butterfly scan enables artifact reduction, contrast improvement, and enhanced corticomedullary junction discrimination. However, the impact of the reduced dose was more noticeable, particularly in the occipital region where susceptibility to bone interference resulted in decreased contrast and compromised corticomedullary junction discrimination.

Background: While the diagnosis of frontotemporal dementia (FTD) is based mostly on clinical features, [¹⁸F]-FDG-PET has been investigated as a potential imaging standard in ambiguous cases, with arterial spin-labeling (ASL) MRI gaining recent interest.

Purpose: The purpose of this study is to conduct a systematic review and meta-analysis on the diagnostic performance of ASL MRI in patients with FTD and compare it with that of [¹⁸F]-FDG-PET.

Data sources: A systematic search of PubMed, Scopus, and Embase was conducted until March 13, 2024.

Study selection: Inclusion criteria were original articles, patients with FTD and/or its variants, use of ASL MR perfusion imaging with or without [¹⁸F]-FDG-PET, and presence of sufficient diagnostic performance data. Exclusion criteria were meeting abstracts, comments, summaries, protocols, letters and guidelines, longitudinal studies, and overlapping cohorts.

Data analysis: The quality of eligible studies was assessed by using the Quality Assessment of Diagnostic Accuracy Studies-2. Pooled sensitivity, specificity, and diagnostic odds ratio (DOR) for [¹⁸F]-FDG-PET and ASL MRI were calculated, and a summary receiver operating characteristic curve was plotted.

Data synthesis: Seven eligible studies were identified, which included a total of 102 patients with FTD. Aside from some of the studies showing, at worst, an unclear risk of bias in patient selection, index test, flow, and timing, all studies showed low risk of bias and applicability concerns in all categories. Data from 4 studies were included in our meta-analysis for ASL MRI and 3 studies for [¹⁸F]-FDG-PET. Pooled sensitivity, specificity, and DOR were 0.70 (95% CI: 0.59-0.79), 0.81 (95% CI: 0.71-0.88), and 8.00 (95% CI: 3.74-17.13) for ASL MRI and 0.88 (95% CI: 0.71-0.96), 0.89 (95% CI: 0.43-0.99), and 47.18 (95% CI: 10.77-206.75) for [¹⁸F]-FDG-PET.

Limitations: The number of studies was relatively small, with a small sample size. The studies used different scanning protocols as well as a mix of diagnostic metrics, all of which might have introduced heterogeneity in the data.

Conclusions: While ASL MRI performed worse than [¹⁸F]-FDG-PET in the diagnosis of FTD, it exhibited a decent diagnostic performance to justify its further investigation as a quicker and more convenient alternative.

Background: The use of a Pipeline Embolization Device (PED) in combination with coils (PEDC) to treat intracranial aneurysms remains unclear as to whether it offers significant benefits for the patients because the results have varied.

Purpose: This study aimed to investigate the clinical outcome of the PEDC compared with the PED in treating intracranial aneurysms.

Data sources: We systematically searched the articles from PubMed, Web of Science, and the Cochrane Library databases published before January 25, 2024.

Study selection: We selected studies comparing the PEDC versus the PED to treat intracranial aneurysms. Patients treated with the PEDC but using dense coiling were excluded from the study.

Data analysis: The clinical outcomes observed in this meta-analysis were intraprocedural complications, postoperative complications (stenosis, stroke, hemorrhage, mortality), favorable outcome (mRS ≤2), complete occlusion rate, and retreatment rate. A forest plot was used to analyze pooled OR of clinical outcomes.

Data synthesis: A total of 3001 subjects from 9 observational studies were included. The PEDC was mainly used to treat larger aneurysms. The PEDC has a significantly higher complete occlusion rate at 6 months (OR = 2.66; 95% CI, 1.26-115.59; P = .01), a lower retreatment rate (OR = 0.18; 95% CI, 0.05-0.07; P = .010), higher stroke-related complications (OR= 1.66, 95% CI, 1.16-2.37; P = .005), and higher hemorrhage-related complications (OR = 1.98; 95% CI, 1.22-13.21; P = .005). There was no significant difference in intraprocedural complications, stenosis-related complications, mortality, favorable outcomes, and complete occlusion at the end of the study.

Limitations: No randomized controlled trials have been performed comparing the PEDC and PED. Considering that all the included studies were observational, the patients' baseline characteristics were not completely balanced.

Conclusions: This meta-analysis study showed that the PEDC in large intracranial aneurysms induces a faster complete occlusion rate at 6 months and a lower retreatment rate. However, it increases the risk of stroke-related postoperative complications, and the faster complete aneurysm occlusion rate found in this study did not correlate with a reduction in long-term aneurysm or distal artery ruptures. Thus, this study suggests the need to find a better strategy to improve long-term hemorrhage-related complications in large intracranial aneurysms.

Background and purpose: Accurately identifying patients with CSF-venous fistulas (CVF) causing spontaneous intracranial hypotension, is a diagnostic dilemma. This conundrum underscores the need for a CVF biomarker to help select who should undergo an invasive myelogram for further diagnostic work-up. β-trace protein (BTP) is the most abundant CNS-derived protein in the CSF and, therefore, is a potential venous biomarker for CVF detection. The purpose of our study was to measure venous BTP levels as a potential CVF biomarker.

Materials and methods: We prospectively enrolled 14 patients with CVFs and measured the BTP in venous blood samples from the paraspinal veins near the CVF and compared those levels with those in the peripheral blood. Myelograms used initially to identify the CVF were evaluated for technique, CVF laterality, CVF level, and the venous drainage pattern. Patient sex and age and symptom duration were also collected. Brain MR images were reviewed for Bern scores. We also measured the peripheral blood BTP levels in 20 healthy controls.

Results: In patients with CVF, the mean BTP level near the CVF was 54.5% higher (0.760 [SD, 0.673] mg/L versus 0.492 [SD, 0.095] mg/L; P = .069) compared with peripheral blood. Nine (64.3%) patients with CVFs had a higher paraspinal BTP level than peripheral BTP level. The 20 control patients had a higher mean peripheral BTP level of 0.720 (SD, 0.191) mg/L compared with patients with CVF (P < .001).

Conclusions: We found that venous blood at the site of the CVF had higher BTP values compared with peripheral blood in most but not all patients with CVF. This finding may reflect the intermittent leaking nature of CVF. Additionally, we found that patients with CVF had a lower peripheral blood BTP level compared with healthy controls. BTP requires further evaluation as a potential CVF biomarker.