AJNR. American journal of neuroradiology最新文献

Background and purpose: Accurate localization of the ventral intermediate nucleus (VIM) within the dentatorubrothalamic tract (DRTT) is critical for effective neurosurgical treatment of essential tremor (ET). This study evaluated the feasibility and anatomic specificity of quantitative susceptibility mapping (QSM) for direct VIM/DRTT visualization, comparing it with conventional diffusion tractography-based reconstructions.

Materials and methods: Twenty-seven participants (10 healthy controls, 17 patients with ET) were enrolled across 2 institutions and imaged on 3T MRI systems. QSM-defined VIM/DRTT regions were manually segmented on the basis of characteristic hypointense susceptibility contrast. Whole-brain diffusion tractography was performed to reconstruct the DRTT, pyramidal tract (PT), and medial lemniscus (ML) tracts. Spatial overlap between QSM- and tractography-defined VIM/DRTT regions was calculated, as well as overlap with neighboring PT and ML tracts to assess specificity.

Results: Two participants were excluded due to insufficient VIM/DRTT streamlines in tractography reconstruction. In healthy controls, QSM- and tractography-defined VIM/DRTT showed high spatial correspondence (left: 87.6% [SD, 5.1%]; right: 85.3% [SD, 6.5%]). Patients with ET had slightly lower overlap (mean range: 71.5%-85.1%). Overlap with neighboring PT and ML tracts was minimal (<3.3%), confirming high anatomic specificity of QSM-derived VIM/DRTT regions.

Conclusions: QSM enables direct visualization of the VIM/DRTT with high spatial agreement with conventional tractography-based approaches while demonstrating minimal overlap with adjacent tracts. These findings support QSM as a complementary or stand-alone imaging technique for improved, patient-specific neurosurgical targeting in ET.

Background and purpose: Although the otic capsule is fully formed at birth, the vestibular aqueduct (VA) continues to mature postnatally. Failure of this maturation-VA hypoplasia-identifies a subgroup of patients with Menière disease and can be detected on CT by measuring the angular trajectory of the VA (ATVA). However, the age at which the ATVA stabilizes and hypoplasia can be reliably diagnosed remains unclear. We, therefore, defined the normal timeline of ATVA development to establish age-specific CT norms for distinguishing physiologic VA development from fetal/hypoplastic arrest.

Materials and methods: We retrospectively reviewed temporal bone and head CTs in 159 children (318 ears) 0-16 years of age without an otologic abnormality. Two head and neck radiologists measured the ATVA and retrolabyrinthine bone (RL) thickness-previously established surrogates of VA hypoplasia-on axial reformatted images. Interreader reliability was assessed by the intraclass correlation coefficient. We modeled the ATVA versus age by using generalized additive mixed models. First-derivative analysis of the age spline identified when ATVA change plateaued. Eighty percent and 95% prediction intervals determined the ages at which the ATVA reliably fell below clinical thresholds (140°, 130°, 120°).

Results: Interreader agreement was excellent (intraclass correlation coefficient = 0.92 ATVA; 0.88, RL thickness). The mean ATVA declined from 135° (SD, 7.5°) in infants to 98° (SD, 6.0°) in adolescents. At the 80% prediction interval, the ATVA upper limit fell below 140° by ∼1.8 years; 130° by ∼3.1 years; and 120° by ∼10.4 years. The 95% interval excluded ATVA ≥140° by ∼3.0 years and ≥130° by ∼10.3 years, but not >120° before 16 years of age. No ears older than 8 years of age fell in the fetal category (≥140°), and none older than 12 years of age fell in the intermediate category (121°-139°). First-derivative analysis showed that ATVA change plateaued at ∼5.0 years. RL thickness of ≥1.2 mm universally corresponded to a mature ATVA (≤120°).

Conclusions: ATVA transitions from a fetal (≥140°) to mature (≤120°) trajectory across the first decade, stabilizing by ∼5 years. ATVA >120° before ∼10 years reflects normal development; after ∼12 years, it indicates adult-persistent hypoplasia. RL thickness of ≥1.2 mm serves as a practical surrogate for mature VA orientation. These benchmarks empower radiologists to differentiate normal maturation from Menière disease associated VA hypoplasia, enabling early risk-stratification and management.

Background and purpose: With the workforce shortage in the United States, neuroadiologists' workloads are increasing with associated increase in burnout and interpretive errors. This article reports on an updated survey deployed to reexamine the neuroradiology work environment in the United States, evaluating changes in key results from a prior survey.

Materials and methods: A survey was deployed to subscribers of the American Journal of Neuroradiology. Selected measures included work hours, volume, subjectively reported errors and malpractice, burnout symptoms, participation in nonclinical activities, intention to retire early or change careers, preparation for early retirement or career change, availability of artificial intelligence (AI) tools and remote work.

Results: Survey respondents (n=113) included 57.5% with teaching responsibilities. There was a high prevalence of burnout with 79% reporting at least 1 symptom, despite an increasing percentage of respondents (50.8%) reporting the availability of advanced informatics or AI tools in their practices. More respondents who have AI tools reported anxiety (30/54; 55.6%) compared with those without AI (P = .04). Being involved in or having a colleague involved in a malpractice suit as a primary defendant was reported by 33% of respondents and was associated with the burnout measure, having difficulty in relaxing after work (P = .03). Part-time work, remote work hours or percentage, or after-hours remote work were not correlated with burnout (P > .11). Need to be faster than optimal for interpreting and signing reports, poorly indicated orders, and increases in work hours, workdays, and risk for malpractice suits were correlated with burnout (P < .05). Intent to retire early was reported by 38.6% of respondents and correlated with all burnout factors (P < .04) and cutbacks in other nonclinical activities (P < .003). Among respondents with intent to retire early or make a career change, 27.9% reported making specific preparations.

Conclusions: Despite the increasing availability of AI tools, US neuroradiologists report high rates of burnout and high rates of intention and preparation to retire early in the face of increasing clinical workloads and workforce shortage. These results underscore the challenges facing the leaders of radiology practices in balancing the growing demand for radiology services and the available and incoming workforce.

Background and purpose: Bell palsy (BP) is the most common cause of facial nerve (FN) palsy. This study aimed to investigate the diagnostic ability of the 3D double-echo steady-state with water excitation (3D-DESS-WE) sequence to visualize pathologic changes in the FN of patients with BP.

Materials and methods: We retrospectively analyzed 30 patients with BP who underwent 3T MRI including 3D-DESS-WE within 30 days of onset and 60 sex- and age (SD, 2) matched controls. Qualitative evaluation of FN signal intensity (SI_FN) and thickness (TH_FN) was performed using a 3-point scale. Quantitative metrics included SI_FN and TH_FN measurements and affected-to-unaffected signal intensity and thickness ratios (SR_A/U and TR_A/U) in the BP group, and right-to-left ratios in controls. Interobserver agreement, group comparisons, correlations with clinical severity (Yanagihara score), and diagnostic performance were assessed. In a subset of 17 matched pairs, the diagnostic performance of contrast-enhanced (CE) T1WI was assessed, and its agreement with 3D-DESS-WE-based qualitative assessment was evaluated.

Results: Qualitative scores for SI_FN and TH_FN were significantly higher in the BP group than in controls (P < .001), with high interobserver agreement (κ = 0.810, 0.788, respectively). When dichotomized (score 0 versus 1-2), qualitative assessments showed good diagnostic performance with a sensitivity and specificity of 0.87 and 0.82 for SI_FN, and 0.90 and 0.80 for TH_FN, respectively. Neither qualitative score correlated significantly with clinical severity. Agreement between 3D-DESS-WE-based and CE T1WI-based qualitative assessments was substantial to almost perfect (κ = 0.766-0.882). In quantitative analysis, both SI_FN and TH_FN were significantly higher on the affected side in the BP group (P < .001), whereas no significant lateral differences were observed in controls. Although SI_FN, TH_FN, and SR_A/U did not correlate significantly with clinical severity, TR_A/U was significantly inversely correlated with the Yanagihara score (r = -0.413, P = .02), which corresponds to a positive correlation with clinical severity. The Yanagihara score was the only independent predictor of TR_A/U in multiple regression analysis (β = -0.425, P = .04). Receiver operating characteristic analysis showed high diagnostic performance: area under the curve = 0.908 for SR_A/U and 0.927 for TR_A/U.

Conclusions: 3D-DESS-WE may be a valuable tool for the routine clinical assessment of BP.

Innovations that introduce new knowledge domains face greater barriers to adoption, often requiring investment in infrastructure, training/education, and cultural change. Sustaining and scaling an advanced clinical vessel wall MR imaging program requires technical resources and subspecialized neuroradiologists with advanced cerebrovascular expertise. A multifaceted educational program, including lectures, reporting templates, and an online resource, was implemented within a large academic Neuroradiology Division to address neuroradiology workforce readiness. Seven faculty "superusers" interested in cerebrovascular imaging were identified to facilitate case discussions and provide daily support for colleagues, clinicians, and MR technologists. Impact was assessed through a 12-month pre-/postintervention survey measuring confidence levels in evaluating vessel wall MR imaging examination appropriateness (a), assessing image quality (b), and diagnostic interpretations (c). Results showed division-wide increases in self-reported confidence and statistically significant increases among the superusers. These results show that a structured, expert-led peer-support model can enhance clinical readiness and sustain advanced imaging programs.

Background and purpose: The TICI score determines the reperfusion grade on DSA after endovascular treatment (EVT) in patients with acute ischemic stroke. Despite successful macrovascular reperfusion, almost one-half of patients have poor clinical outcomes. In addition to the large vessels, DSA also depicts the passage of contrast in the capillaries. We aim to study differences in DSA perfusion parameters generated from the time-intensity curves that might differentiate between good and poor clinical outcome in patients who achieved successful reperfusion.

Materials and methods: Patients from the MR CLEAN Registry with an ICA, M1, and M2 occlusion, and successful reperfusion extended TICI (eTICI ≥2b) were selected. Perfusion parameters of the capillary pixels were computed on post-EVT DSA by deconvolving the time-intensity curve with the arterial input function obtained from the ICA. We extracted 4 perfusion parameters: CBV, CBF, time-to-maximum (Tmax), and mean transit time (MTT). The association between the perfusion parameters and favorable functional outcome at 90 days (0-2 mRS) was analyzed using logistic regression with adjustments for prognostic patient characteristics including eTICI.

Results: In total, 743 of 5768 patients were included. There was no association between eTICI scores and favorable functional outcome. In contrast, a shorter MTT and Tmax were associated with favorable functional outcome (adjusted OR, 1.25 [95% CI, 1.03-1.51], 1.39 [95% CI, 1.06-1,82]). DSA-CBV and DSA-CBF were not significantly associated with mRS.

Conclusions: Quantifying DSA perfusion parameters provides additional information about reperfusion status and could contribute to differentiating between favorable and unfavorable functional outcomes. The code for producing the quantitative digital subtraction perfusion angiography is publicly available at: https://github.com/RuishengSu/perfDSA.

Over the past 25 years, progress in the treatment of CNS tumors has been limited, and outcomes for malignancies, such as glioblastoma and diffuse intrinsic pontine glioma, remain dismal. There has been great interest in harnessing endovascular neurointerventional techniques and using the cerebral vasculature as a route for therapeutic delivery in neuro-oncology. Several selective intra-arterial clinical trials are currently underway targeting a range of CNS tumors with different therapeutic agents. The Society of NeuroInterventional Surgery (SNIS) convened the inaugural Neurointerventional Oncology Summit, which was held on April 26-27, 2024, at the University of Texas MD Anderson Cancer Center in Houston, Texas. The group consisted of neurointerventionists, neurosurgeons, neuro-oncologists, neuroradiologists, basic scientists, and industry representatives who are current practitioners in this emerging space. We report the current state of practice and our efforts to develop an organizational platform to treat patients with CNS cancers and to advance research in this emerging field. Endovascular surgical neuro-oncology is an emerging clinical endeavor that aims to provide novel therapeutic options for CNS cancers. Novel therapeutic agents, including yttrium-90, oncolytic viruses, and cellular immunotherapy, are being tested as intra-arterial therapy. Technological advances in imaging modalities, selective methods of BBB opening, and devices and catheters will aid the advancement of the field. Multidisciplinary cooperation and collaboration will be integral to the success of this endeavor.

Background and purpose: CTA is an established technique for imaging intracranial arteries, enabling rapid assessment of stenosis, vessel occlusions and aneurysm in various acute and elective clinical settings. This study aims to evaluate. Our purpose was to evaluate the diagnostic benefits of deep learning-based image reconstruction for neurovascular imaging by using ultra-high-resolution (UHR)-CT compared with standard hybrid iterative reconstruction (HIR) applied to both UHR-CT and normal-resolution (NR)-CT data sets.

Materials and methods: This retrospective, single-center study included 100 consecutive patients who underwent cranial CT and CTA for acute neurologic symptoms. Imaging was performed on a UHR-CT system. HIR was applied to CTA data sets reconstructed with: 1) an NR matrix of 512 × 512 pixels and 0.5 mm slice thickness (NR-CTA) and 2) a UHR matrix of 1024 × 1024 pixels and 0.25 mm slice thickness (UHR-CTA). Downscaling from the UHR data was performed for the NR-CTA by averaging 4 voxels (2 × 2) into 1 voxel, effectively converting the 1024 × 1024 matrix to a 512 × 512 matrix. A vendor-specific deep-learning algorithm trained for neurovascular analysis was additionally applied to UHR-CTA data sets (deep-learning UHR-CTA [DL-UHR-CTA]). Quantitative analyses included SNR, contrast-to-noise ratio (CNR), and slope evaluations in 3 vessel sections: the MCA, basilar artery (BA), and a subcortical vessel (SV) by using a Matlab-tool. Qualitative assessments of image quality, contrast, artifacts, diagnostic confidence, and vessel assessability (proximal, intermediate, and subcortical segments) were conducted by 2 radiologists by using a 4-point Likert scale.

Results: No significant differences between DL-UHR-CTA and NR-CTA were observed in SNR and CNR for BA and MCA; however, DL-UHR-CTA outperformed NR-CTA in SNR and CNR for SV (P < .001). NR-CTA revealed significantly lower SNR for BA and MCA (P < .05) and lower CNR for BA (P = .02) compared with UHR-CTA. No significant differences in CNR for MCA and SNR for SV were observed between NR-CTA and UHR-CTA. DL-UHR-CTA (-359.6 ± 116.0) was significantly steeper than both NR-CTA (-226.5 ± 64.2 Hounsfield unit [HU]) and UHR-CTA (-249.2 ± 67.1 HU) across all vessel segments (P < .001). Qualitative analysis showed DL-UHR-CTA provided significantly better overall image quality, contrast, diagnostic confidence, and accessibility across all vessel segments, with fewer artifacts, compared with UHR-CTA and NR-CTA (P < .05).

Conclusions: Deep learning-based reconstruction of UHR-CTA images in neurovascular imaging significantly improves overall image quality, vascular delineation, SNR, and CNR compared with HIR alone.

Background and purpose: In patients with acute large vessel occlusion (LVO) of the MCA and underlying intracranial artery stenosis (ICAS), rescue stenting (RS) has been associated with better angiographic outcomes and higher rates of functional independence compared with mechanical thrombectomy (MT) alone. However, uncertainty exists regarding safety of RS in patients at higher risk for intracranial bleeding. The primary aim of this retrospective multicenter study was to compare safety outcomes between patients with acute ICAS-LVO of the MCA who underwent MT and RS with or without prior intravenous thrombolysis (IVT). Efficacy outcomes were assessed as a secondary aim.

Materials and methods: We screened the prospective databases of 26 stroke centers across Europe, the United States, and China for consecutive patients with acute MCA ICAS-LVO who received RS. Patients were divided into 2 groups based on prior administration of IVT: IVT/RS and no-IVT/RS. Propensity score matching (PSM), based on a set of covariates that also included periprocedural antiplatelet therapies, was used to estimate the effect of IVT treatment. Primary safety outcomes were the occurrence of symptomatic intracranial hemorrhage (sICH) and 90-day mortality.

Results: After PSM, 52 pairs of patients were available for analysis. No significant differences were observed between the 2 groups regarding rates of sICH (11.5% in IVT/RS group versus 9.6% in no-IVT/RS group; OR = 1.2; 95% CI, 0.4-4.3; P = .75) and 90-day mortality (14.3% in the IVT/RS group versus 11.7% in the no-IVT/RS group; OR = 1.3; 95% CI, 0.4-4.2; P = .71). There were also no significant differences in the occurrence of parenchymal hemorrhage types 1 and 2, successful recanalization rates, and 90-day functional outcome.

Conclusions: The safety of RS in ICAS-LVO is not significantly affected by prior IVT administration. Furthermore, IVT does not result in improved recanalization and clinical outcome. These findings should be interpreted with caution and require validation through future randomized controlled studies.

Background and purpose: Brain injury in monochorionic pregnancies complicated by twin-to-twin transfusion syndrome (TTTS) remains incompletely understood, and reported patterns vary widely due to heterogeneous imaging protocols. This study aimed to characterize fetal brain lesions after endoscopic laser surgery for TTTS using a structured MRI-based classification.

Materials and methods: We conducted a retrospective observational study of TTTS pregnancies treated with endoscopic equatorial laser photocoagulation between January 2012 and January 2023. Fetuses with post-treatment brain abnormalities on MRI were included. MRI was performed 2-4 weeks after laser therapy following a standardized protocol. Lesions were independently reviewed and classified by neuroradiologists as ischemic or hemorrhagic, then categorized by radiologic pattern (focal, multifocal, diffuse) and vascular territory. Clinical variables, including donor/recipient status and Quintero stage, were compared using Fisher's exact test and the Mann-Whitney U test.

Results: Thirty-six fetuses met inclusion criteria. Twenty (55.6%) were ex-recipients and 16 (44.4%) ex-donors. MRI was performed at a median gestational age of 22.7 weeks (range: 19.7-31.7). Ischemic lesions were identified in 31/36 fetuses (86.1%) and hemorrhagic lesions in 5/36 (13.9%). Among ischemic injuries, focal lesions predominated (22/31, 71.0%), most commonly within the middle cerebral artery (MCA) territory (18/22, 81.8%). Multifocal (6/31, 19.3%) and diffuse (3/31, 9.7%) patterns were less frequent. Hemorrhagic lesions involved the cerebellum (2/5, 40.0%) or thalamo-caudate sulcus (3/5, 60.0%). Ex-recipients more often exhibited focal ischemic lesions, while ex-donors showed a higher proportion of hemorrhagic injuries; however, no significant differences were detected by donor/recipient status or by Quintero stage.

Conclusions: A structured MRI-based classification demonstrates that focal ischemia in the MCA territory is the predominant brain lesion after laser-treated TTTS, supporting thromboembolism as a likely mechanism. These findings contribute to understanding lesion patterns in TTTS and may aid future diagnostic and prognostic assessments.

Abbreviations: ACA＝ anterior cerebral artery; DWI＝ diffusion-weighted imaging; GA＝ gestational age; ICA＝ internal carotidartery; IUD＝ intrauterine demise; IUGR/S-IUGR＝ (selective) intrauterine growth restriction; IVH＝ intraventricular hemorrhage; MC＝ monochorionic; PCA＝ posterior cerebral artery; TAPS＝ twin anemia-polycythemia sequence; TC＝ thalamo-caudate; TTTS＝twin-to-twin transfusion syndrome.