Journal of Neuroimaging最新文献

Background and Purpose

The role of high-resolution nerve ultrasound (HRUS) in the diagnosis of chemotherapy-induced polyneuropathy is unclear. The present prospective longitudinal controlled study evaluates the utility of HRUS in vincristine-induced polyneuropathy (VIPN).

Methods

Twelve patients receiving vincristine and 12 healthy age-matched controls were included. Visits before and 3 weeks, 8 weeks, and 6 months after the start of vincristine treatment included clinical examination, the total neuropathy score (TNS), nerve conduction studies (NCSs), and HRUS of the bilateral median, ulnar, radial, tibial, peroneal, and sural nerve cross-sectional areas (CSAs).

Results

Median TNS increased from 0 points (interquartile range [IQR] 0) to 0.5 points (IQR 1, p = .26) at Week 3 and to 4 points (IQR 2.5, p < .001) at Week 8. At 6 months, there was a nonsignificant decrease to 2 points (IQR 2, p = .66). HRUS of individual nerve sites showed no significant changes in CSA and intranerve variability. The total CSA of all entrapment sites increased significantly (p = .007) at Week 8. Sensory nerve action potentials decreased significantly after 6 months (sural nerve, p = .001; radial nerve, p = .004; ulnar and median nerve, p < .001). The tibial nerve compound muscle action potential (p = .006) and nerve conduction velocity (p < .001) were reduced.

Conclusions

At mid-treatment, there is an increase in the total CSA at entrapment sites parallel to an increase in clinical symptoms. In individual nerve sites, HRUS does not detect significant signs of VIPN. NCSs exhibit signs of a predominantly sensory axonal polyneuropathy. The clinical examination remains the most sensitive tool in the early detection of VIPN.

Background and purpose

Despite multimodal treatment of glioblastoma (GBM), recurrence beyond the initial tumor volume is inevitable. Moreover, conventional MRI has shortcomings that hinder the early detection of occult white matter tract infiltration by tumor, but diffusion tensor imaging (DTI) is a sensitive probe for assessing microstructural changes, facilitating the identification of progression before standard imaging. This sensitivity makes DTI a valuable tool for predicting recurrence. A systematic review was therefore conducted to investigate how DTI, in comparison to conventional MRI, can be used for predicting GBM progression.

Methods

We queried three databases (PubMed, Web of Science, and Scopus) using the search terms: (diffusion tensor imaging OR DTI) AND (glioblastoma OR GBM) AND (recurrence OR progression). For included studies, data pertaining to the study type, number of GBM recurrence patients, treatment type(s), and DTI-related metrics of recurrence were extracted.

Results

In all, 16 studies were included, from which there were 394 patients in total. Six studies reported decreased fractional anisotropy in recurrence regions, and 2 studies described the utility of connectomics/tractography for predicting tumor migratory pathways to a site of recurrence. Three studies reported evidence of tumor progression using DTI before recurrence was visible on conventional imaging.

Conclusions

These findings suggest that DTI metrics may be useful for guiding surgical and radiotherapy planning for GBM patients, and for informing long-term surveillance. Understanding the current state of the literature pertaining to these metrics’ trends is crucial, particularly as DTI is increasingly used as a treatment-guiding imaging modality.

Background and Purpose

Flow diversion has become a key treatment option for complex intracranial aneurysms. Recent advancements include coated flow diverters (FDs), designed to potentially reduce the need for dual antiplatelet therapy, thereby removing the associated secondary risks while maintaining patency and low complication rates. Comparing coated and uncoated FDs may offer insights into long-term outcomes and treatment optimization.

Method

In this retrospective single-center study, we investigated the data of 21 consecutive patients with cerebral aneurysms, treated between 2021 and 2023 with the coated Derivo 2heal Embolization Device and the uncoated Derivo Embolization Device (both Acandis). We described the procedure and analyzed clinical and radiological data, along with long-term outcomes after 18 months of follow-up.

Results

Nine patients (42.9%) had incidental, while 12 (57.1%) had symptomatic aneurysms, including 10 with World Federation of Neurosurgical Societies classification IV subarachnoid hemorrhages. Aneurysm locations included mostly the internal carotid (n = 9) and the vertebral artery (n = 7). All FDs were successfully deployed: 11 patients received the coated and 10 the uncoated device. After 18 months, 73.3% of patients had favorable outcomes (modified Rankin Score 0-2). One coated FD occluded asymptomatically after 6 months, and one uncoated FD occluded immediately but could be recanalized.

Conclusions

We observed favorable occlusion rates for both coated and uncoated FDs. The role of dual antiplatelet therapy remains debated. Large multicenter studies are essential to evaluate the patency of coated compared to uncoated FDs and determine whether they can reduce thrombogenicity, potentially allowing for less or no antiplatelet therapy in emergencies.

Background and Purpose

Differentiation between functioning and nonfunctioning pituitary adenomas/pituitary neuroendocrine tumors (PAs) is clinically relevant. The goal of this study was to determine the feasibility of using time-dependent diffusion MRI (dMRI) for microstructural characterization of PAs.

Methods

The study included 54 participants, 24 with functioning PA and 30 with nonfunctioning PA. Time-dependent dMRI of the pituitary gland was performed using an inner field-of-view echo-planar imaging based on 2-dimensional-selective radiofrequency excitations with oscillating gradient and pulsed gradient preparation (effective diffusion time: 7.1 and 36.3 ms) at b-values of 0 and 1000 seconds/mm². Each tumor had its apparent diffusion coefficients (ADCs) measured at two diffusion times (ADC_7.1 ms and ADC_36.3 ms), its ADC change (cADC), and relative ADC change. The mean values of diffusion parameters were compared between functioning and nonfunctioning PAs. We compared the diffusion parameters of nonfunctioning PAs with those of each type of hormone-producing PAs. The diagnostic performances of the diffusion parameters were assessed.

Results

The cADC was significantly higher in functioning PAs than nonfunctioning PAs (p = .0124). The receiver operating characteristic (ROC) curve analysis revealed that cADC (area under the ROC curve [AUC] = .677, p = .017) is effective in distinguishing between functioning and nonfunctioning PAs. The cADC was significantly higher in growth hormone (GH)-producing PAs compared to nonfunctioning PAs (p = .006). The ROC curve analysis indicated that cADC (AUC = .771, p < .001) effectively distinguishes between GH-producing and nonfunctioning PAs.

Conclusions

The cADC derived from time-dependent dMRI could distinguish between functioning and nonfunctioning PAs, particularly those producing GH.

Multiple sclerosis-related cognitive impairment (MSrCI) affects most patients with multiple sclerosis (MS), significantly contributing to disability and socioeconomic challenges. MSrCI manifests across all disease stages, mainly impacting working memory, information processing, and attention. To date, the underlying mechanisms of MSrCI remain unclear, with its pathogenesis considered multifactorial. While conventional MRI findings correlate with MSrCI, there is no consensus on reliable imaging metrics to detect or diagnose cognitive impairment (CI). Functional MRI (fMRI) has provided unique insights into the brain's neuroplasticity mechanisms, revealing evidence of compensatory mechanisms in response to tissue damage, both beneficial and maladaptive. This review summarizes the current literature on the application of resting-state fMRI (rs-fMRI) and task-based fMRI (tb-fMRI) in understanding neuroplasticity and its relationship with cognitive changes in people with MS (pwMS). Searches of databases, including PubMed/Medline, Embase, Scopus, and the Web of Science, were conducted for the most recent fMRI cognitive studies in pwMS. Key findings ifrom rs-fMRI studies reveal disruptions in brain connectivity and hub integration, leading to CI due to decreased network efficiency. tb-fMRI studies highlight abnormal brain activation patterns in pwMS, with evidence of increased fMRI activity in earlier disease stages as a beneficial compensatory response, followed by reduced activation correlating with increased lesion burden and cognitive decline as the disease progresses. This suggests a gradual exhaustion of compensatory mechanisms over time. These findings support fMRI not only as a diagnostic tool for MSrCI but also as a potential imaging biomarker to improve our understanding of disease progression.

Background and Purpose

Neuromix is a fast, motion robust multi-contrast sequence capable of providing all diagnostic contrasts in ∼3.5 minutes. However, more evaluation is needed across the various contrasts compared to gold standard, optimized sequences routinely used in the clinic. The goal of this study was to prospectively determine how NeuroMix performs in the clinical setting compared to routine clinical MRI.

Methods

NeuroMix and routine clinical MRI sequences were acquired on a 3 Tesla clinical scanner for 39 patients clinically indicated for brain MRI. Three radiologists were asked to assess the diagnostic confidence of NeuroMix compared to the routine MRI using a series of questions. Signal-to-noise and contrast-to-noise ratios (SNR and CNR) were assessed for NeuroMix. Fleiss’ free-marginal multirater kappa was calculated for the qualitative assessment performed by the radiologists.

Results

Radiologists were comfortable substituting or reading some of the NeuroMix sequences in place of the corresponding conventional sequence for some contrasts, including diffusion-weighted imaging, single-shot T₂, and susceptibility-weighted imaging. The image quality, SNR, and CNR allowed the radiologists to visualize anatomy and pathology on NeuroMix images. There was no significant difference between coefficient of variation for the apparent diffusion coefficient maps (p = .084).

Conclusions

Analysis revealed both positives and some pitfalls of NeuroMix. However, these results indicate Neuromix as having the capability to be a backup sequence in case artifacts are present in routine sequences, or potentially a replacement for some contrasts altogether.

Background and Purpose

Neuromyelitis optica spectrum disorder (NMOSD) affects the optic nerves and spinal cord but can also cause focal brain inflammation. Subcortical pathology may contribute to the etiology of cognitive deficits in NMOSD. Using myelin water imaging, we investigated cerebral normal-appearing white matter (NAWM) and thalamic metrics and their association with cognition in NMOSD participants compared to healthy controls (HC).

Methods

Seventeen NMOSD participants and 21 HC were scanned on a 3.0-Tesla MRI scanner using a multicomponent driven-equilibrium single-pulse observation of T₁ and T₂ protocol. Tissue compartment and thalamic volumes (normalized to intracranial volume), T₁ relaxation time, and myelin water fraction (MWF) were reported. Eleven NMOSD participants underwent the Symbol Digit Modalities Test (SDMT) for cognitive evaluation. Group comparisons were performed using Student's t-test. The association between thalamic metrics and SDMT score was assessed using multiple regression analysis with age as a covariate.

Results

Compared to HC, NMOSD participants had reduced white matter volume (−14.2%, p < .0001), increased T₁ relaxation time (+2.29%, p = .022), and lower MWF (−3.64%, p = .024) in NAWM. NMOSD group had a trend for smaller thalamic volumes than HC (−5.52%, p = .082) and no differences in thalamic MWF (p = .258) or T₁ (p = .714). Thalamic T₁ predicted SDMT score (adjusted R² = .51, p = .04) when controlling for age.

Conclusions

NAWM in NMOSD demonstrates diffuse abnormalities with increased water content and demyelination, suggesting a diffuse disease process overlooked by focal inflammation measures. Increased water content, as a biomarker for diffuse thalamic pathology, may partially explain cognitive impairment in NMOSD.

Background and Purpose

Different types of physical training can lead to changes in brain activity and function, and these changes can vary depending on the type of training. However, it remains unclear whether there are commonalities in how different types of training affect brain activity and function. The purpose of this study is to compare the brain activity states of professional athletes with those of ordinary university students and to explore the relationship between training and differences in brain activity states.

Methods

This study primarily utilizes resting-state MRI and the degree centrality metric to investigate spontaneous brain activity in 86 high-level athletes with extensive training and 74 age- and gender-matched nonathletes. Additionally, a correlation analysis between brain activity in relevant regions and years of training was conducted.

Results

The analysis revealed that, compared to nonathletes, high-level athletes exhibited reduced activity in the Calcarine (a visual area) and Middle Temporal Gyrus. Furthermore, changes in the activity of the Calcarine and Middle Temporal Gyrus were significantly correlated with the number of years of professional training.

Conclusions

The study results indicate that long-term physical training is associated with changes in brain activity in athletes, providing insights into the neural mechanisms underlying behavioral performance in professional athletes.

Background and Purpose

The absence of a consensus data quality control (DQC) process inhibits the widespread adoption of MR spectroscopy. Poor DQC can lead to unreliable clinical diagnosis and irreproducible research conclusions. Currently, manual visual assessment or the standard quantitative metrics of signal-to-noise, linewidth, and model fit are used as classifiers, but these measures may not be sufficient. To supplement standard metrics, this paper proposes a novel automated DQC pipeline named Visual Evaluative Control Technology Of Resonance Spectroscopy (VECTORS).

Methods

Manual DQC ratings were conducted on 7180 spectra obtained from 110 young adults using short-echo chemical shift imaging at 3 Tesla. Four reviewers conducted manual ratings on the presence of artifacts and location of metabolites. The ratings were labor intensive, taking over 180 hours. VECTORS was developed to quantify their DQC criteria, detecting artifacts that present as duplicate peaks, vertical shifts, and glutamine + glutamate and myoinositol peak shapes. Run on the same data using a standard laptop, VECTORS only took 2 hours.

Results

The manual ratings were not monotonic to the standard quantitative metrics. VECTORS correctly flagged spectra that the manual ratings missed. VECTORS accurately flagged an additional 126 poor DQ spectra that consensus cutoffs of the standard quantitative metrics deemed good DQ.

Conclusion

Standard quantitative metrics may not account for all DQC artifacts as they are not monotonic to the manual ratings. However, manual ratings are labor intensive, subjective, and irreproducible. VECTORS addresses these issues and should be used in conjunction with standard quantitative metrics.

Background and Purpose

Sonothrombolysis is a potential adjunctive therapy for large vessel occlusion (LVO) stroke. Bedside ultrasound image-guided high-intensity focused ultrasound (HIFU) therapy could deliver higher energy therapeutic ultrasound to the thrombus with higher precision than what was previously accomplished in human trials. The aim is to test the feasibility of diagnostic transcranial contrast-enhanced ultrasound (CEUS) to image the occlusion site and continuously maintain the guidance image on-target for a sufficient exposure time for HIFU to be effective during LVO stroke evaluation and treatment.

Methods

This prospective, single center, observational cohort study included adult patients, presenting within 6 hours of stroke symptom onset, with LVO identified on computed tomography angiography (CTA). A hand-held CEUS imaging study was initiated following CTA and lasted up to 30 minutes. The primary outcome is the proportion of patients where a guidance CEUS image of the occlusion was achieved.

Results

A CEUS image of the occluded artery was obtained in 32/35 of the included patients. The median total imaging time was 23 minutes (interquartile range 15-30). Patients undergoing thrombectomy had a lower total imaging time (17 vs. 29.5 minutes, p = .002). When imaging was successful, on-target image was maintained for only 58% (standard deviation 23.8%) of total imaging time. No complications related to CEUS were observed.

Conclusions

This feasibility study explored the use of diagnostic transcranial CEUS for continuous imaging of occlusion sites in LVO strokes. Challenges in maintaining target image during HIFU were identified, highlighting the need for technical advances for clinical application.