Journal of Neuroimaging最新文献

Background and purpose: Prolonged venous transit (PVT), derived from computed tomography perfusion (CTP) time-to-maximum (T_max) maps, reflects compromised venous outflow (VO) in acute ischemic stroke due to large vessel occlusion (AIS-LVO). Poor VO is associated with worse clinical outcomes, but pre-treatment markers predictive of PVT are not well described.

Methods: We conducted a retrospective analysis of 189 patients with anterior circulation AIS-LVO who underwent baseline CT evaluation, including non-contrast CT, CT angiography, and CTP. PVT was assessed on T_max maps; PVT+ was defined as T_max ≥ 10 s within the posterior superior sagittal sinus or torcula. Baseline clinical data were collected. Multivariable logistic regression identified independent associations between pre-treatment markers and PVT.

Results: PVT+ was identified in 65 patients (34%). In multivariable analysis, higher admission National Institutes of Health Stroke Scale (NIHSS) scores (adjusted odds ratio [aOR], 1.05 per point; 95% confidence interval [CI], 1.01-1.11; P  =  0.028) and male sex (aOR, 1.98; 95% CI, 1.03-3.89; P  =  0.043) were independently associated with PVT+.

Conclusions: Higher admission NIHSS scores and male sex are independently associated with PVT in anterior circulation AIS-LVO, suggesting that readily available clinical markers may help identify patients with poor VO profiles.

Background and purpose: Anxiety during pregnancy is common, and exposure to heightened anxiety during pregnancy may influence children's brain development and functioning. However, it is unclear if exposure to low levels of anxiety in utero would also impact the developing brain. The current prospective and longitudinal study included 40 healthy pregnant women without pregnancy complications or previous diagnosis of anxiety disorders.

Methods: Pregnant women's anxiety symptoms were measured at 12, 24, and 36 weeks of gestation. Their healthy, full-term offspring underwent a brain MRI scan without sedation, including resting-state functional MRI, at 2 weeks postnatal age. The associations between neonatal brain cortical functional connectivity originating from the amygdala and maternal prenatal anxiety symptom scores were examined using correlational analyses.

Results: Significant correlations were identified after controlling for child sex, postmenstrual age at MRI, and mother's depression symptom scores. Higher maternal anxiety during pregnancy was related to alterations in offspring's functional connectivity between the amygdala and other brain regions involved in fear learning. Specifically, higher maternal prenatal anxiety during the first trimester of pregnancy was associated with lower connectivity between the amygdala and fusiform gyrus and higher connectivity between the amygdala and thalamus. Higher maternal prenatal anxiety during the third trimester was also associated with lower connectivity between the amygdala and fusiform gyrus.

Conclusions: The findings from this study indicate that exposure to low levels of anxiety in utero may also impact offspring brain development and functioning, particularly brain regions that are important for threat detection.

Background and purpose: Endovascular thrombectomy (EVT) for acute ischemic stroke (AIS) with M2 segment occlusion of the middle cerebral artery (MCA) is debatable. This study assessed the efficacy, safety, and functional outcomes of EVT in M2 occlusion patients, examining differences in outcomes based on the dominance of the occluded segment (DomM2 vs. Non-DomM2).

Methods: A prospective cohort of 108 patients with AIS resulting from M2 segment occlusion of the MCA who underwent EVT was analyzed. We compared demographic, clinical, angiographic, and clinical outcome data (National Institutes of Health Stroke Scale [NIHSS] score at 24 h and modified Rankin Scale [mRS] score at 3 months) between patients with or without DomM2. The primary endpoint was the first-pass effect (FPE), defined as achieving modified Thrombolysis in Cerebral Infarction 2c-3 after one pass. We examined the symptomatic hemorrhagic transformation, 3-month functional outcomes, and mortality rates.

Results: Seventy-five patients (69.44%) had DomM2. FPE rates (48.48% for DomM2; 42.66% for Non-DomM2, p = 0.521), final successful recanalization rate, and functional outcomes were comparable between subgroups. Direct aspiration yielded a higher FPE rate (56.25%). FPE was associated with lower NIHSS scores at discharge (median, 2 [interquartile range 0-4] vs. 5 [1-10]; p < 0.001) and higher 3-month functional independence (83.33% vs. 60.34%; p < 0.001). Direct aspiration independently predicted FPE, with a 75% likelihood compared to stent retriever (p = 0.007).

Conclusions: EVT is a safe and effective treatment for acute M2 occlusion regardless of the dominance of the M2 segment. Direct aspiration used as a frontline technique increases the likelihood of FPE.

Background and purpose: This study aims to investigate the longitudinal changes in translocator protein (TSPO) following stroke in different brain regions and potential associations with chronic brain infarction.

Methods: Twelve patients underwent SPECT using the TSPO tracer 6-Chloro-2-(4'-123I-Iodophenyl)-3-(N,N-Diethyl)-Imidazo[1,2-a]Pyridine-3-Acetamide, as well as structural MRI, at 10, 41, and 128 days (median) after ischemic infarction in the middle cerebral artery. TSPO expression was measured in lesional (MRI lesion and SPECT lesion), connected (pons and ipsilesional thalamus), and nonconnected (ipsilesional cerebellum and contralesional occipital cortex) regions. Correlations were explored between the volume of chronic infarction and TSPO expression in nonconnected regions of interest (ROIs) at 128 days RESULTS: Throughout the study period, TSPO levels decreased by 24%-33% in lesional ROIs, while levels increased in connected ROIs by 35%-69% and in nonconnected ROIs by 53%-77%. At 128 days poststroke, TSPO expression in ipsilesional cerebellum positively correlated with chronic infarction volume (p = 0.002, r² = 0.72).

Conclusions: This study expands the current knowledge of spatial and temporal TSPO expression in humans by quantifying TSPO changes in lesional, connected, and nonconnected brain regions at three time points after cerebral infarction as well as correlating late-stage TSPO upregulation and chronic infarction volume.

Background and purpose: The central vein sign (CVS) is a diagnostic imaging biomarker for multiple sclerosis (MS). FLAIR* is a combined MRI contrast that provides high conspicuity for CVS at 3 Tesla (3T), enabling its sensitive and accurate detection in clinical settings. This study evaluated whether CVS conspicuity of 3T FLAIR* is reliable across imaging sites and MRI vendors and whether gadolinium (Gd) contrast increases CVS conspicuity.

Methods: A cross-sectional, multicenter study recruited adults referred for possible diagnosis of MS at 10 sites. FLAIR* contrast was generated using high-resolution T2*-weighted (acquired pre- and post-injection of Gd) and T2-weighted fluid-attenuated inversion recovery (T2-FLAIR) brain images at 3T from two MRI vendors. Lesions and veins were segmented to compute lesion-to-vein contrast-to-noise ratio (CNR_{lesion-to-vein}), a quantitative measure of CVS conspicuity. CNR_{lesion-to-vein} measures for pre- and post-Gd FLAIR* were compared across sites and vendors.

Results: Eighty-seven participants from nine sites were included in the analysis. There was no significant difference in mean CNR_{lesion-to-vein} between sites for pre-Gd (p-value = 0.07) or post-Gd (p-value = 0.27) FLAIR*. There were also no significant differences between vendors for pre-Gd (p-value = 0.10) or post-Gd (p-value = 0.31) FLAIR*. Patient-level pairwise differences in CNR_{lesion-to-vein} between pre-Gd and post-Gd FLAIR* revealed a significant increase for post-Gd FLAIR* (p-value < 0.001).

Conclusions: CVS conspicuity on 3T FLAIR* is consistent across imaging sites and MRI vendors. Moreover, Gd-based contrast agent significantly improved CVS conspicuity on 3T FLAIR*. These findings support the implementation of FLAIR* in clinical settings for MS.

Background and purpose: Endovascular thrombectomy (EVT) is the standard for acute ischemic stroke from large vessel occlusion, but post-EVT functional independence varies. Brain atrophy, linked to higher cerebrospinal fluid volume (CSFV), may affect outcomes. Baseline CSFV could predict EVT benefit by assessing brain health. We aimed to quantify total CSFV from clinical T1-weighted (w) magnetic resonance imaging (MRI) to assess global brain atrophy and its association with functional outcomes following successful EVT.

Methods: We performed a retrospective analysis of patients achieving thrombolysis-in-cerebral-infarction ≥2b revascularization via prospectively maintained single-institution stroke thrombectomy registry (n = 432) between 2015 and 2021. We included 214 patients (mean age 67.5 ± 14.6, 49% female) with acceptable quality MRI within 14 days of EVT and available modified Rankin-scale (mRS) at 90 days post EVT. Clinical T1w images were transformed into high-resolution images using the convolutional neural-network SynthSR. FreeSurfer software was then used to estimate total cranial CSFV. To correct for head size, percentage of CSFV to intracranial volume was used.

Results: Baseline CSFV% significantly predicted 90-day mRS in an ordinal regression model adjusted for baseline mRS (p < 0.001). Further modeling was performed to account for age, sex, 24-h National-Institutes-Health-Stroke-Scale (NIHSS), smoking history, prior stroke, hypertension, congestive heart failure, hemoglobin-A1c, atrial fibrillation, and Alberta-Stroke-Program-Early-CT-Score (ASPECTS). Total CSFV% remained an independent predictor of 90-day mRS (p = 0.012). CSFV% did not significantly predict the occurrence of any type of hemorrhagic transformation in a logistic regression model.

Conclusions: Increased CSFV% correlates with poorer functional outcomes post EVT. Total CSFV% may serve as a useful imaging biomarker for clinicians determining patient prognostication prior to EVT.

Background and purpose: In idiopathic normal pressure hydrocephalus (iNPH) patients, cerebrospinal fluid (CSF) flow is typically evaluated with a cardiac-gated two-dimensional (2D) phase-contrast (PC) MRI through the cerebral aqueduct. This approach is limited by the evaluation of a single location and does not account for respiration effects on flow. In this study, we quantified the cardiac and respiratory contributions to CSF movement at multiple intracranial locations using a real-time 2D PC-MRI and evaluated the diagnostic value of CSF dynamics biomarkers in classifying iNPH patients.

Methods: This study included 37 participants: 16 iNPH, 10 Alzheimer's disease (AD), and 11 cognitively unimpaired (CU) controls. Anatomical and real-time (non-gated) PC images were acquired in a 3T Philips scanner. CSF flow was assessed at the foramen magnum, fourth ventricle, Sylvian fissure, lateral ventricle, and cerebral aqueduct. We calculated three CSF dynamics biomarkers: mean velocity amplitude, cardiac signal power, and respiratory signal power. Biomarkers from each location were evaluated for classifying iNPH versus AD and CU using support vector machine (SVM). A p-value of 0.05 or less was considered statistically significant.

Results: The velocity amplitude and cardiac signal power were significantly reduced in iNPH compared to CU (p < 0.005) and AD (p < 0.05) at the lateral ventricle. The SVM model using biomarkers from the lateral ventricle performed significantly better at classifying iNPH than the other locations in terms of accuracy (p < 0.005) and diagnostic odds ratio (p < 0.05).

Conclusion: Evaluation of CSF movement beyond the cerebral aqueduct may aid in identifying patients with and understanding the pathophysiology of iNPH.

Background and purpose: Working memory, a primary cognitive domain, is often impaired in pediatric brain tumor survivors, affecting their attention and processing speed. This study investigated the long-term effects of treatments, including surgery, radiotherapy (RT), and chemotherapy (CT), on working memory tracts in children with posterior fossa tumors (PFTs) using resting-state functional MRI (rs-fMRI) and diffusion MRI tractography.

Methods: This study included 16 medulloblastoma (MB) survivors treated with postoperative RT and CT, 14 pilocytic astrocytoma (PA) survivors treated with surgery alone, and 16 healthy controls from the Imaging Memory after Pediatric Cancer in children, adolescents, and young adults study (NCT04324450). Working memory tracts were identified by combining seed masks from rs-fMRI maps and whole-brain tractography from diffusion MRI. Connectivity alterations were assessed qualitatively and quantitatively, alongside neuropsychological evaluations and correlations with behavioral outcomes and mean supratentorial dose.

Results: Compared to controls, MB survivors exhibited significant impairments in the working memory network, including reductions in tract volume (TV), fiber density, fiber cross-section (FC), mean streamline length (MLS), and fractional anisotropy (FA) (all p = 0.04). Lower working memory scores were correlated with reduced TV and FA in MB survivors. Higher mean supratentorial doses were associated with lower TV, FC, and FA values across multiple tracts, particularly in the arcuate and superior longitudinal fasciculi.

Conclusions: Tractography-derived features highlighted white matter damage as a biomarker of treatment-related neurotoxicity in PFTs survivors. These findings underscore the detrimental impact of RT and CT on working memory networks and emphasize the importance of preserving cognitive function during treatment planning.

Background and purpose: We investigated the relationship between serotonergic and dopaminergic specific binding transporter ratios (SBRs) over 4 years in Parkinson's disease (PD) patients. We assessed serotonergic innervation's potential compensatory role for dopaminergic denervation, association with PD symptoms, and involvement in the development of levodopa-induced dyskinesia (LID).

Methods: SBRs of the midbrain and striatum were evaluated from [I-123] N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane SPECT images at baseline and after 4 years. Correlations between SBRs and PD symptoms were analyzed, alongside interval changes.

Results: Study included 177 PD patients (110 males, 67 females; mean age 61.0 ± 9.0 years). Significant worsening was observed in Hoehn and Yahr staging and Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part II and III scores over 4 years (p < 0.05, p < 0.001, and p < 0.001, respectively). SBRs of the caudate, putamen, and midbrain declined significantly (p < 0.001). Midbrain and striatal SBRs correlated significantly at both baseline and 4-year follow-up (p < 0.0001). Striatal SBRs correlated significantly with MDS-UPDRS II and III scores at both time points, while midbrain SBRs correlated with changes in MDS-UPDRS III scores over the 4 years (p < 0.01). Putamen and midbrain SBRs at 4 years were significantly lower in patients who developed LID compared to those who did not (p < 0.05).

Conclusion: The study demonstrates correlations between midbrain and putamen SBRs and MDS-UPDRS scores over 4 years in PD patients. Midbrain serotonin dysfunction may contribute to the development of LID.

Intracranial pressure (ICP) monitoring is a cornerstone of neurocritical care in managing severe brain injury. However, current invasive ICP monitoring methods carry significant risks, including infection and intracranial hemorrhage, and are contraindicated in certain clinical situations. Additionally, these methods are not universally available. Optic nerve sheath diameter (ONSD) measurement presents a promising noninvasive alternative for ICP monitoring, though its clinical adoption has been limited due to its operator dependence and inconsistencies in imaging acquisition and measurement techniques. Automating both ONSD image acquisition and measurement could enhance accuracy and reliability, thereby improving its utility as a noninvasive ICP estimation tool. A range of image analysis and machine learning (ML) techniques have been applied to address these challenges. In this paper, we provide a narrative review of the current literature on ONSD automation, examining the strengths and limitations of classical image analysis and ML models in improving ONSD-based ICP assessment.