Publications by authors named "Chencai Wang"

14 Publications

  • Page 1 of 1

A study of 3D radial density adapted trajectories for sodium imaging.

Magn Reson Imaging 2021 Jul 13. Epub 2021 Jul 13.

Department of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, CA, USA.

Sodium imaging typically employs ultrashort echo time radial, density adapted and cones trajectories to capture the rapidly decaying short T2 signal. The present study considers the parameter choices involved in the use of these trajectories in terms of their impact on the resolution and signal to noise ratio. Many parameters have a strong effect on these image properties, particularly the number of spokes used which impacts voxel size. The present article develops an understanding of the trade-offs involved and how to choose optimal (or at least reasonable) parameter values. This has a practical role in designing clinical protocols for imaging sodium.
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http://dx.doi.org/10.1016/j.mri.2021.07.004DOI Listing
July 2021

Supraspinal functional and structural plasticity in patients undergoing surgery for degenerative cervical myelopathy.

J Neurosurg Spine 2021 Jun 11:1-9. Epub 2021 Jun 11.

2Neurosurgery, and.

Objective: The aim of this study was to investigate cerebral reorganization, both structurally and functionally, occurring in patients with degenerative cervical myelopathy (DCM) after surgical decompression.

Methods: In the current observational study of 19 patients, high-resolution T1-weighted structural MRI and resting-state functional MRI scans were obtained pre- and postoperatively in patients with DCM and healthy controls (HCs). The resting-state functional MRI data were utilized to perform region-of-interest (ROI)-to-ROI and ROI-to-voxel functional connectivity (FC) analysis and were similarly compared between and within cohorts. Macroscopic structural plasticity was evaluated by assessing for changes in cortical thickness within the DCM cohort after decompression surgery.

Results: Prior to surgery, FC patterns were significantly different between DCM patients and HCs in cerebral areas responsible for postural control, motor regulation, and perception and integration of sensory information. Significantly stronger FC between the cerebellum and frontal lobes was identified in DCM patients postoperatively compared with DCM patients preoperatively. Additionally, increased FC between the cerebellum and primary sensorimotor areas was found to be positively associated with neurological improvement in patients with DCM. No macroscopic structural changes were observed in the DCM patients after surgery.

Conclusions: These results support the authors' hypothesis that functional changes within the brain are associated with effective postoperative recovery, particularly in regions associated with motor regulation and with perception and integration of sensory information. In particular, increased FC between the cerebellum and the primary sensorimotor after surgery appears to be associated with neurological improvement. Macroscopic morphological changes may be too subtle to be detected within 3 months after surgery.
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http://dx.doi.org/10.3171/2020.11.SPINE201688DOI Listing
June 2021

Cortical morphometric correlational networks associated with cognitive deficits in first episode schizophrenia.

Schizophr Res 2021 05 16;231:179-188. Epub 2021 Apr 16.

Dept. of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States of America; Dept. of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States of America; Neuroscience Interdisciplinary Graduate Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States of America. Electronic address:

Schizophrenia (SCZ) is a chronic cognitive and behavioral disorder associated with abnormal cortical activity during information processing. Several brain structures associated with the seven performance domains evaluated using the MATRICS (Measurement and Treatment Research to Improve Cognition in Schizophrenia) Consensus Cognitive Battery (MCCB) have shown cortical volume loss in first episode schizophrenia (FES) patients. However, the relationship between morphological organization and MCCB performance remains unclear. Therefore, in the current observational study, high-resolution structural MRI scans were collected from 50 FES patients, and the morphometric correlation network (MCN) using cortical volume was established to characterize the cortical pattern associated with poorer MCCB performance. We also investigated topological properties, such as the modularity, the degree and the betweenness centrality. Our findings show structural volume was directly and strongly associated with the cognitive deficits of FES patients in the precuneus, anterior cingulate, and fusiform gyrus, as well as the prefrontal, parietal, and sensorimotor cortices. The medial orbitofrontal, fusiform, and superior frontal gyri were not only identified as the predominant nodes with high degree and betweenness centrality in the MCN, but they were also found to be critical in performance in several of the MCCB domains. Together, these results suggest a widespread cortical network is altered in FES patients and that performance on the MCCB domains is associated with the core pathophysiology of SCZ.
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http://dx.doi.org/10.1016/j.schres.2021.04.001DOI Listing
May 2021

Modified RANO, Immunotherapy RANO, and Standard RANO Response to Convection-Enhanced Delivery of IL4R-Targeted Immunotoxin MDNA55 in Recurrent Glioblastoma.

Clin Cancer Res 2021 Jul 16;27(14):3916-3925. Epub 2021 Apr 16.

Medicenna BioPharma, Houston, Texas.

Purpose: The current study compared the standard response assessment in neuro-oncology (RANO), immunotherapy RANO (iRANO), and modified RANO (mRANO) criteria as well as quantified the association between progression-free (PFS) and overall survival (OS) in an immunotherapy trial in recurrent glioblastoma (rGBM).

Patients And Methods: A total of 47 patients with rGBM were enrolled in a prospective phase II convection-enhanced delivery of an IL4R-targeted immunotoxin (MDNA55-05, NCT02858895). Bidirectional tumor measurements were created by local sites and centrally by an independent radiologic faculty, then standard RANO, iRANO, and mRANO criteria were applied.

Results: A total of 41 of 47 patients (mean age 56 ± 11.7) were evaluable for response. PFS was significantly shorter using standard RANO compared with iRANO (log-rank, < 0.0001; = 0.3) and mRANO ( < 0.0001; = 0.3). In patients who died and had confirmed progression on standard RANO, no correlation was observed between PFS and OS (local, = 0.47; central, = 0.34). Using iRANO, a weak association was observed between confirmed PFS and OS via local site measurements ( = 0.017), but not central measurements ( = 0.18). A total of 24 of 41 patients (59%) were censored using iRANO and because they lacked confirmation of progression 3 months after initial progression. A strong correlation was observed between mRANO PFS and OS for both local ( = 0.66, < 0.0001) and centrally determined reads ( = 0.57, = 0.0007).

Conclusions: No correlation between radiographic PFS and OS was observed for standard RANO or iRANO, but a correlation was observed between PFS and OS using the mRANO criteria. Also, the iRANO criteria was difficult to implement due to need to confirm progression 3 months after initial progression, censoring more than half the patients.
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http://dx.doi.org/10.1158/1078-0432.CCR-21-0446DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8282697PMC
July 2021

Detection of cerebral reorganization associated with degenerative cervical myelopathy using diffusion spectral imaging (DSI).

J Clin Neurosci 2021 Apr 5;86:164-173. Epub 2021 Feb 5.

Dept. of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Neuroscience Interdisciplinary Graduate Program, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA; Dept. of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Degenerative Cervical Myelopathy (DCM) is a spinal cord disorder that causes significant physical disabilities in older patients. While most DCM research focuses on the spinal cord, widespread reorganization of the brain may occur to compensate for functional impairment. This observational study used diffusion spectrum imaging (DSI) to examine reorganization of cerebral white matter associated with neurological impairment as measured by the modified Japanese Orthopedic Association (mJOA), and severity of neck disability as measured by the Neck Disability Index (NDI) score. A total of 47 patients were included in the cervical spondylosis (CS) cohort: 38 patients with DCM (mean mJOA = 14.6, and mean NDI = 12.0), and 9 neurologically asymptomatic patients with spinal cord compression (mJOA = 18, and mean NDI = 7.0). 28 healthy volunteers (HCs) served as the control group. Lower generalized fractional anisotropy (GFA) was observed throughout much of the brain in patients compared to HCs (p < 0.05). Fiber pathways associated with somatosensory functions, such as the corpus callosum and corona radiata, showed increased quantitative anisotropy (QA) in patients compared to HCs. Correlation analyses further suggested that structural connectivity was enhanced to compensate for neurological dysfunction within sensorimotor regions, where fibers such as the posterior corona radiata had NQA values that were negatively associated with mJOA (p = 0.0020, R = 0.2935) and positively associated with NDI score (p = 0.0164, R = 0.1889). Altogether, these results suggest that DCM and neurologically asymptomatic spinal cord compression patients tend to have long-term reorganization within the brain, particularly in those regions responsible for the perception and integration of sensory information, motor regulation, and pain modulation.
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http://dx.doi.org/10.1016/j.jocn.2021.01.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8007933PMC
April 2021

A physical phantom for amine chemical exchange saturation transfer (CEST) MRI.

MAGMA 2021 Aug 23;34(4):569-580. Epub 2021 Jan 23.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, University of California, Los Angeles, Los Angeles, CA, USA.

Objective: To develop a robust amine chemical exchange saturation transfer (CEST) physical phantom, validate the temporal stability, and create a supporting software for automatic image processing and quality assurance.

Materials And Methods: The phantom was designed as an assembled laser-cut acrylic rack and 18 vials of phantom solutions, prepared with different pHs, glycine concentrations, and gadolinium concentrations. We evaluated glycine concentrations using ultraviolet absorbance for 70 days and measured the pH, relaxation rates, and CEST contrast for 94 days after preparation. We used Spearman's correlation to determine if glycine degraded over time. Linear regression and Bland-Altman analysis were performed between baseline and follow-up measurements of pH and MRI properties.

Results: No degradation of glycine was observed (p > 0.05). The pH and MRI measurements stayed stable for 3 months and showed high consistency across time points (R = 1.00 for pH, R, R, and CEST contrast), which was further validated by the Bland-Altman plots. Examples of automatically generated reports are provided.

Discussion: We designed a physical phantom for amine CEST-MRI, which is easy to assemble and transfer, holds 18 different solutions, and has excellent short-term chemical and MRI stability. We believe this robust phantom will facilitate the development of novel sequences and cross-scanners validations.
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http://dx.doi.org/10.1007/s10334-020-00902-zDOI Listing
August 2021

Maximum Uptake and Hypermetabolic Volume of 18F-FDOPA PET Estimate Molecular Status and Overall Survival in Low-Grade Gliomas: A PET and MRI Study.

Clin Nucl Med 2020 Dec;45(12):e505-e511

Department of Radiological Science, David Geffen School of Medicine.

Purpose: We evaluated F-FDOPA PET and MRI characteristics in association with the molecular status and overall survival (OS) in a large number of low-grade gliomas (LGGs).

Methods: Eighty-six patients who underwent F-FDOPA PET and MRI and were diagnosed with new or recurrent LGGs were retrospectively evaluated with respect to their isocitrate dehydrogenase (IDH) and 1p19q status (10 IDH wild type, 57 mutant, 19 unknown; 1p19q status in IDH mutant: 20 noncodeleted, 37 codeleted). After segmentation of the hyperintense area on fluid-attenuated inversion recovery image (FLAIRROI), the following were calculated: normalized SUVmax (nSUVmax) of F-FDOPA relative to the striatum, F-FDOPA hypermetabolic volume (tumor-to-striatum ratios >1), FLAIRROI volume, relative cerebral blood volume, and apparent diffusion coefficient within FLAIRROI. Receiver operating characteristic curve and Cox regression analyses were performed.

Results: PET and MRI metrics combined with age predicted the IDH mutation and 1p19q codeletion statuses with sensitivities of 73% and 76% and specificities of 100% and 94%, respectively. Significant correlations were found between OS and the IDH mutation status (hazard ratio [HR] = 4.939), nSUVmax (HR = 2.827), F-FDOPA hypermetabolic volume (HR = 1.048), and FLAIRROI volume (HR = 1.006). The nSUVmax (HR = 151.6) for newly diagnosed LGGs and the F-FDOPA hypermetabolic volume (HR = 1.038) for recurrent LGGs demonstrated significant association with OS.

Conclusions: Combining F-FDOPA PET and MRI with age proved useful for predicting the molecular status in patients with LGGs, whereas the nSUVmax and F-FDOPA hypermetabolic volume may be useful for prognostication.
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http://dx.doi.org/10.1097/RLU.0000000000003318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7950323PMC
December 2020

Compensatory brainstem functional and structural connectivity in patients with degenerative cervical myelopathy by probabilistic tractography and functional MRI.

Brain Res 2020 12 17;1749:147129. Epub 2020 Sep 17.

Dept. of Neurosurgery, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States. Electronic address:

Degenerative cervical myelopathy (DCM) is the most common cause of spinal cord impairment in adults. Previous supraspinal investigations have primarily focused on cortical changes in this patient population. As the nexus between the brain and the spinal cord, the brainstem has been understudied in patients with DCM. The current study examined the structural and functional connectivity between the brainstem and cortex in DCM patients using probabilistic tractography and resting-state functional MRI. A total of 26 study patients and 32 neurologically intact, healthy volunteers (HCs) participated in this prospective analysis. The study cohort included DCM patients (n = 18), as well as neurologically asymptomatic patients with evidence of cervical spine degenerative changes and spinal cord compression (n = 8). Results of the study demonstrated significant differences in fiber density (FD), fiber cross-section (FDC), and the functional connectivity (FC) between the study cohort and HCs. Through seeding the brainstem, the study cohort showed reductions in FD and FDC along the corticospinal tract, including regions extending through the corona radiata and internal capsule. By correlating FD and FDC with the Neck Disability Index (NDI), and the modified Japanese Orthopaedic Association (mJOA), we identified increasing total volume of projections to the thalamus, basal ganglia, and internal capsule, and increased functional connectivity to visual network and the posterior parietal cortices. These results support our hypothesis that DCM patients tend to have long-term FC reorganization not only localized to sensorimotor regions, but also to regulatory and visual processing regions, designed to ultimately preserve neurological function.
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http://dx.doi.org/10.1016/j.brainres.2020.147129DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7606789PMC
December 2020

Influence of phosphate concentration on amine, amide, and hydroxyl CEST contrast.

Magn Reson Med 2021 02 16;85(2):1062-1078. Epub 2020 Sep 16.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, University of California, Los Angeles, Los Angeles, California, USA.

Purpose: To evaluate the influence of phosphate on amine, amide, and hydroxyl CEST contrast using Bloch-McConnell simulations applied to physical phantom data.

Methods: Phantom solutions of 4 representative metabolites with exchangeable protons-glycine (α-amine protons), Cr (η-amine protons), egg white protein (amide protons), and glucose (hydroxyl protons)-were prepared at different pH levels (5.6 to 8.9) and phosphate concentrations (5 to 80 mM). CEST images of the phantom were collected with CEST-EPI sequence at 3 tesla. The CEST data were then fitted to full Bloch-McConnell equation simulations to estimate the exchange rate constants. With the fitted parameters, simulations were performed to evaluate the intracellular and extracellular contributions of CEST signals in normal brain tissue and brain tumors, as well as in dynamic glucose-enhanced experiments.

Results: The exchange rates of α-amine and hydroxyl protons were found to be highly dependent on both pH and phosphate concentrations, whereas the exchange rates of η-amine and amide protons were pH-dependent, albeit not catalyzed by phosphate. With phosphate being predominantly intracellular, CEST contrast of α-amine exhibited a higher sensitivity to changes in the extracellular microenvironment. Simulations of dynamic glucose-enhanced signals demonstrated that the contrast between normal and tumor tissue was mostly due to the extracellular CEST effect.

Conclusion: The proton exchange rates in some metabolites can be greatly catalyzed by the presence of phosphate at physiological concentrations, which substantially alters the CEST contrast. Catalytic agents should be considered as confounding factors in future CEST-MRI research. This new dimension may also benefit the development of novel phosphate-sensitive imaging methods.
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http://dx.doi.org/10.1002/mrm.28481DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8258865PMC
February 2021

Multiparametric MR-PET measurements in hypermetabolic regions reflect differences in molecular status and tumor grade in treatment-naïve diffuse gliomas.

J Neurooncol 2020 Sep 14;149(2):337-346. Epub 2020 Sep 14.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, 924 Westwood Blvd, Suite 615, Los Angeles, CA, 90024, USA.

Purpose: To assess whether hypermetabolically-defined regions of interest (ROIs) on 3,4-dihydroxy-6-[18F]-fluoro-L-phenylalanine (FDOPA) positron emission tomography (PET) could be used to evaluate physiological features and whether there are measurable differences between molecular subtypes and tumor grades.

Methods: Sixty-eight treatment-naïve glioma patients who underwent FDOPA PET and magnetic resonance imaging (MRI) were retrospectively included. Fluid-attenuated inversion recovery hyperintense regions (FLAIR) were segmented. FDOPA hypermetabolic regions (FDOPA, tumor-to-striatum ratios > 1) within FLAIR were extracted. Normalized maximum standardized uptake value (nSUV), volume of each ROI, and median relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) within FLAIR or FDOPA were calculated. Imaging metrics were compared using Students t or Mann-Whitney U tests. Area under the curve (AUC) of receiver-operating characteristic curves were used to determine whether imaging metrics within FLAIR or FDOPA can discriminate different molecular statuses or grades.

Results: Using either FLAIR or FDOPA, the nSUV and rCBV were significantly higher and the ADC was lower in isocitrate dehydrogenase (IDH) wild-type than mutant gliomas, and in higher-grade gliomas (HGGs) than lower-grade gliomas (LGGs). The FDOPA volume was significantly higher in 1p19q codeleted than non-codeleted gliomas, and in HGGs than LGGs. Although not significant, imaging metrics extracted by FDOPA discriminated molecular status and tumor grade more accurately than those extracted by FLAIR (AUC of IDH status, 0.87 vs. 0.82; 1p19q status, 0.78 vs. 0.73; grade, 0.87 vs. 0.76).

Conclusion: FDOPA hypermetabolic ROI may extract useful imaging features of gliomas, which can illuminate biological differences between different molecular status or tumor grades.
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http://dx.doi.org/10.1007/s11060-020-03613-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7682113PMC
September 2020

Decorin expression is associated with predictive diffusion MR phenotypes of anti-VEGF efficacy in glioblastoma.

Sci Rep 2020 09 9;10(1):14819. Epub 2020 Sep 9.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers (CVIB), Dept. of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, 924 Westwood Blvd, Suite 615, Los Angeles, CA, 90024, USA.

Previous data suggest that apparent diffusion coefficient (ADC) imaging phenotypes predict survival response to anti-VEGF monotherapy in glioblastoma. However, the mechanism by which imaging may predict clinical response is unknown. We hypothesize that decorin (DCN), a proteoglycan implicated in the modulation of the extracellular microenvironment and sequestration of pro-angiogenic signaling, may connect ADC phenotypes to survival benefit to anti-VEGF therapy. Patients undergoing resection for glioblastoma as well as patients included in The Cancer Genome Atlas (TCGA) and IVY Glioblastoma Atlas Project (IVY GAP) databases had pre-operative imaging analyzed to calculate pre-operative ADC values, the average ADC in the lower distribution using a double Gaussian mixed model. ADC values were correlated to available RNA expression from these databases as well as from RNA sequencing from patient derived mouse orthotopic xenograft samples. Targeted biopsies were selected based on ADC values and prospectively collected during resection. Surgical specimens were used to evaluate for DCN RNA and protein expression by ADC value. The IVY Glioblastoma Atlas Project Database was used to evaluate DCN localization and relationship with VEGF pathway via in situ hybridization maps and RNA sequencing data. In a cohort of 35 patients with pre-operative ADC imaging and surgical specimens, DCN RNA expression levels were significantly larger in high ADC tumors (41.6 vs. 1.5; P = 0.0081). In a cohort of 17 patients with prospectively targeted biopsies there was a positive linear correlation between ADC levels and DCN protein expression between tumors (Pearson R = 0.3977; P = 0.0066) and when evaluating different targets within the same tumor (Pearson R = 0.3068; P = 0.0139). In situ hybridization data localized DCN expression to areas of microvascular proliferation and immunohistochemical studies localized DCN protein expression to the tunica adventitia of blood vessels within the tumor. DCN expression positively correlated with VEGFR1 & 2 expression and localized to similar areas of tumor. Increased ADC on diffusion MR imaging is associated with high DCN expression as well as increased survival with anti-VEGF therapy in glioblastoma. DCN may play an important role linking the imaging features on diffusion MR and anti-VEGF treatment efficacy. DCN may serve as a target for further investigation and modulation of anti-angiogenic therapy in GBM.
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http://dx.doi.org/10.1038/s41598-020-71799-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7481206PMC
September 2020

Diffusion MRI changes in the anterior subventricular zone following chemoradiation in glioblastoma with posterior ventricular involvement.

J Neurooncol 2020 May 1;147(3):643-652. Epub 2020 Apr 1.

UCLA Brain Tumor Imaging Laboratory (BTIL), Center for Computer Vision and Imaging Biomarkers, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, USA.

Introduction: There is growing evidence that the subventricular zone (SVZ) plays a key role in glioblastoma (GBM) tumorigenesis. However, little is known regarding how the SVZ, which is a harbor for adult neural stem cells, may be influenced by chemoradiation. The current diffusion-weighted imaging (DWI) study explored ipsilateral and contralateral alterations in the anterior SVZ in GBM patients with posterior enhancing lesions following chemoradiation.

Methods: Forty GBM patients with tumor involvement in the posterior SVZ (mean age = 57 ± 10; left-hemisphere N = 25; right-hemisphere N = 15) were evaluated using DWI before and after chemoradiation. Regions-of-interest were drawn on the ipsilesional and contralesional anterior SVZ on apparent diffusion coefficient (ADC) maps for both timepoints. ADC histogram analysis was performed by modeling a bimodal, double Gaussian distribution to obtain ADC, defined as the mean of the lower Gaussian distribution.

Results: The ipsilesional SVZ had lower ADC values compared to the contralesional SVZ before treatment (mean difference = 0.025 μm/ms; P = 0.007). Following chemoradiation, these changes were no longer observed (mean difference = 0.0025 μm/ms; P > 0.5), as ADC values of the ipsilesional SVZ increased (mean difference = 0.026 μm/ms; P = 0.037). An increase in ipsilesional ADC was associated with shorter progression-free (P = 0.0119) and overall survival (P = 0.0265).

Conclusions: These preliminary observations suggest baseline asymmetry as well as asymmetric changes in the SVZ proximal (ipsilesional) to the tumor with respect to contralesional SVZ regions may be present in GBM, potentially implicating this region in tumorigenesis and/or treatment resistance.
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http://dx.doi.org/10.1007/s11060-020-03460-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769136PMC
May 2020

Neck disability in patients with cervical spondylosis is associated with altered brain functional connectivity.

J Clin Neurosci 2019 Nov 13;69:149-154. Epub 2019 Aug 13.

Dept. of Radiological Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Physics and Biology in Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States; Dept. of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States. Electronic address:

Cervical degenerative disease is a major cause of neck disability, but it has been understudied in patients with cervical spondylotic (CS), largely due to the fact that the neurological impairment associated with this condition tends to be the primary treatment focus. This observational study examined the cerebral functional alterations occurring in advanced cervical spondylosis and myelopathy using resting state functional MRI. Associations between functional connectivity (FC) and neck disability using the Neck Disability Index (NDI) were assessed. Results of the study demonstrated an increase in FC with increasing in neck disability in regions associated with sensorimotor system (both postcentral gyri and precentral gyri, bilaterally, with the SMA; bilateral precentral gyri and the left postcentral gyrus, with the left superior frontal gyrus; bilateral SMA and the left putamen, with the superior frontal gyri). Accounting for the difference in neurological function (mJOA score), strong connectivity between the precentral gyri and the SMA associated with the neck disability. Consistent with studies in chronic pain conditions, these findings suggest neck disability is associated with altered cerebral FC in cervical spondylosis patients.
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http://dx.doi.org/10.1016/j.jocn.2019.08.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829058PMC
November 2019

Effective heating of magnetic nanoparticle aggregates for in vivo nano-theranostic hyperthermia.

Int J Nanomedicine 2017 28;12:6273-6287. Epub 2017 Aug 28.

Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, USA.

Magnetic resonance (MR) nano-theranostic hyperthermia uses magnetic nanoparticles to target and accumulate at the lesions and generate heat to kill lesion cells directly through hyperthermia or indirectly through thermal activation and control releasing of drugs. Preclinical and translational applications of MR nano-theranostic hyperthermia are currently limited by a few major theoretical difficulties and experimental challenges in in vivo conditions. For example, conventional models for estimating the heat generated and the optimal magnetic nanoparticle sizes for hyperthermia do not accurately reproduce reported in vivo experimental results. In this work, a revised cluster-based model was proposed to predict the specific loss power (SLP) by explicitly considering magnetic nanoparticle aggregation in in vivo conditions. By comparing with the reported experimental results of magnetite FeO and cobalt ferrite CoFeO magnetic nanoparticles, it is shown that the revised cluster-based model provides a more accurate prediction of the experimental values than the conventional models that assume magnetic nanoparticles act as single units. It also provides a clear physical picture: the aggregation of magnetic nanoparticles increases the cluster magnetic anisotropy while reducing both the cluster domain magnetization and the average magnetic moment, which, in turn, shift the predicted SLP toward a smaller magnetic nanoparticle diameter with lower peak values. As a result, the heating efficiency and the SLP values are decreased. The improvement in the prediction accuracy in in vivo conditions is particularly pronounced when the magnetic nanoparticle diameter is in the range of ~10-20 nm. This happens to be an important size range for MR cancer nano-theranostics, as it exhibits the highest efficacy against both primary and metastatic tumors in vivo. Our studies show that a relatively 20%-25% smaller magnetic nanoparticle diameter should be chosen to reach the maximal heating efficiency in comparison with the optimal size predicted by previous models.
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http://dx.doi.org/10.2147/IJN.S141072DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5584909PMC
March 2018
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