1,063 research outputs found
Relationships among auditory representations and overall musicianship of classical and non-classical music students
The focus of this study is on the relationships among three basic auditory representations as well as their interaction with a measure of overall musicianship (sight-singing) among a group of classical and non-classical university music students (N = 112) selected from three different universities. Students were enrolled in level one of an aural skills course at the time. Basic auditory representations included were tonic centrality, measured by Colwell’s (1968) Feeling for Tonal Center, tonal grouping, measured by Colwell’s (1968) Auditory-Visual Discrimination, and harmonic function grouping, measured by a revised version of Holahan, Saunders and Goldberg’s (2000) assessment. I evaluated relationships by correlating scores on each measure and also compared these relationships among classical and non-classical music students.
The participants in this study were the most skilled at forming auditory representations of tonic centrality and non-classical musicians significantly (p = .002) outperformed classical musicians in this area. Tonic centrality was also most strongly correlated with overall musicianship (τ = .45, p < .001) within the sample, and this relationship appeared to be stronger among non-classical musicians (τ = .52, p < .001) than among classical musicians (τ = .39, p < .001). This difference may be accounted for by the increased reliance on grounding in a tonal center required by the musical activities of a typical non-classical music student.
Given the changing balance of musical endeavors present in tertiary music schools today (Lehmann, Sloboda, & Woody, 2007), educators are encouraged to better understand the particular strengths non-classical musicians may bring to the classroom in terms of ear-based musical abilities. Likewise, music educators on each level are encouraged to incorporate ear-based activities such as improvisation and playing by ear to the benefit of musicians of all genres
DCE and DW‐MRI monitoring of vascular disruption following VEGF‐Trap treatment of a rat glioma model
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92143/1/nbm1814.pd
Leveraging Mathematical Modeling to Quantify Pharmacokinetic and Pharmacodynamic Pathways: Equivalent Dose Metric
Treatment response assays are often summarized by sigmoidal functions comparing cell survival at a single timepoint to applied drug concentration. This approach has a limited biophysical basis, thereby reducing the biological insight gained from such analysis. In particular, drug pharmacokinetic and pharmacodynamic (PK/PD) properties are overlooked in developing treatment response assays, and the accompanying summary statistics conflate these processes. Here, we utilize mathematical modeling to decouple and quantify PK/PD pathways. We experimentally modulate specific pathways with small molecule inhibitors and filter the results with mechanistic mathematical models to obtain quantitative measures of those pathways. Specifically, we investigate the response of cells to time-varying doxorubicin treatments, modulating doxorubicin pharmacology with small molecules that inhibit doxorubicin efflux from cells and DNA repair pathways. We highlight the practical utility of this approach through proposal of the “equivalent dose metric.” This metric, derived from a mechanistic PK/PD model, provides a biophysically-based measure of drug effect. We define equivalent dose as the functional concentration of drug that is bound to the nucleus following therapy. This metric can be used to quantify drivers of treatment response and potentially guide dosing of combination therapies. We leverage the equivalent dose metric to quantify the specific intracellular effects of these small molecule inhibitors using population-scale measurements, and to compare treatment response in cell lines differing in expression of drug efflux pumps. More generally, this approach can be leveraged to quantify the effects of various pharmaceutical and biologic perturbations on treatment response
Real-Time Compressive Sensing MRI Reconstruction Using GPU Computing and Split Bregman Methods
Compressive sensing (CS) has been shown to enable dramatic acceleration of MRI acquisition in some applications. Being an iterative reconstruction technique, CS MRI reconstructions can be more time-consuming than traditional inverse Fourier reconstruction. We have accelerated our CS MRI reconstruction by factors of up to 27 by using a split Bregman solver combined with a graphics processing unit (GPU) computing platform. The increases in speed we find are similar to those we measure for matrix multiplication on this platform, suggesting that the split Bregman methods parallelize efficiently. We demonstrate that the combination of the rapid convergence of the split Bregman algorithm and the massively parallel strategy of GPU computing can enable real-time CS reconstruction of even acquisition data matrices of dimension 40962 or more, depending on available GPU VRAM. Reconstruction of two-dimensional data matrices of dimension 10242 and smaller took ~0.3 s or less, showing that this platform also provides very fast iterative reconstruction for small-to-moderate size images
Imaging biomarker roadmap for cancer studies.
Imaging biomarkers (IBs) are integral to the routine management of patients with cancer. IBs used daily in oncology include clinical TNM stage, objective response and left ventricular ejection fraction. Other CT, MRI, PET and ultrasonography biomarkers are used extensively in cancer research and drug development. New IBs need to be established either as useful tools for testing research hypotheses in clinical trials and research studies, or as clinical decision-making tools for use in healthcare, by crossing 'translational gaps' through validation and qualification. Important differences exist between IBs and biospecimen-derived biomarkers and, therefore, the development of IBs requires a tailored 'roadmap'. Recognizing this need, Cancer Research UK (CRUK) and the European Organisation for Research and Treatment of Cancer (EORTC) assembled experts to review, debate and summarize the challenges of IB validation and qualification. This consensus group has produced 14 key recommendations for accelerating the clinical translation of IBs, which highlight the role of parallel (rather than sequential) tracks of technical (assay) validation, biological/clinical validation and assessment of cost-effectiveness; the need for IB standardization and accreditation systems; the need to continually revisit IB precision; an alternative framework for biological/clinical validation of IBs; and the essential requirements for multicentre studies to qualify IBs for clinical use.Development of this roadmap received support from Cancer Research UK and the Engineering and Physical Sciences Research Council (grant references A/15267, A/16463, A/16464, A/16465, A/16466 and A/18097), the EORTC Cancer Research Fund, and the Innovative Medicines Initiative Joint Undertaking (grant agreement number 115151), resources of which are composed of financial contribution from the European Union's Seventh Framework Programme (FP7/2007-2013) and European Federation of Pharmaceutical Industries and Associations (EFPIA) companies' in kind contribution
Predicting the Spatio-Temporal Response of Recurrent Glioblastoma Treated With Rhenium-186 Labelled Nanoliposomes
Rhenium-186 (186Re) labeled nanoliposome (RNL) therapy for recurrent glioblastoma patients has shown promise to improve outcomes by locally delivering radiation to affected areas. To optimize the delivery of RNL, we have developed a framework to predict patient-specific response to RNL using image-guided mathematical models.
METHODS: We calibrated a family of reaction-diffusion type models with multi-modality imaging data from ten patients (NCR01906385) to predict the spatio-temporal dynamics of each patient\u27s tumor. The data consisted of longitudinal magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) to estimate tumor burden and local RNL activity, respectively. The optimal model from the family was selected and used to predict future growth. A simplified version of the model was used in a leave-one-out analysis to predict the development of an individual patient\u27s tumor, based on cohort parameters.
RESULTS: Across the cohort, predictions using patient-specific parameters with the selected model were able to achieve Spearman correlation coefficients (SCC) of 0.98 and 0.93 for tumor volume and total cell number, respectively, when compared to the measured data. Predictions utilizing the leave-one-out method achieved SCCs of 0.89 and 0.88 for volume and total cell number across the population, respectively.
CONCLUSION: We have shown that patient-specific calibrations of a biology-based mathematical model can be used to make early predictions of response to RNL therapy. Furthermore, the leave-one-out framework indicates that radiation doses determined by SPECT can be used to assign model parameters to make predictions directly following the conclusion of RNL treatment.
STATEMENT OF SIGNIFICANCE: This manuscript explores the application of computational models to predict response to radionuclide therapy in glioblastoma. There are few, to our knowledge, examples of mathematical models used in clinical radionuclide therapy. We have tested a family of models to determine the applicability of different radiation coupling terms for response to the localized radiation delivery. We show that with patient-specific parameter estimation, we can make accurate predictions of future glioblastoma response to the treatment. As a comparison, we have shown that population trends in response can be used to forecast growth from the moment the treatment has been delivered.In addition to the high simulation and prediction accuracy our modeling methods have achieved, the evaluation of a family of models has given insight into the response dynamics of radionuclide therapy. These dynamics, while different than we had initially hypothesized, should encourage future imaging studies involving high dosage radiation treatments, with specific emphasis on the local immune and vascular response
Predicting High-Grade Glioma Response to Chemoradiation via MRI-Calibrated
https://openworks.mdanderson.org/sumexp21/1085/thumbnail.jp
Current and Future Trends in Magnetic Resonance Imaging Assessments of the Response of Breast Tumors to Neoadjuvant Chemotherapy
The current state-of-the-art assessment of treatment response in breast cancer is based on the response evaluation criteria in solid tumors (RECIST). RECIST reports on changes in gross morphology and divides response into one of four categories. In this paper we highlight how dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted MRI (DW-MRI) may be able to offer earlier, and more precise, information on treatment response in the neoadjuvant setting than RECIST. We then describe how longitudinal registration of breast images and the incorporation of intelligent bioinformatics approaches with imaging data have the potential to increase the sensitivity of assessing treatment response. We conclude with a discussion of the potential benefits of breast MRI at the higher field strength of 3T. For each of these areas, we provide a review, illustrative examples from clinical trials, and offer insights into future research directions
An untrained deep learning method for reconstructing dynamic magnetic resonance images from accelerated model-based data
The purpose of this work is to implement physics-based regularization as a
stopping condition in tuning an untrained deep neural network for
reconstructing MR images from accelerated data. The ConvDecoder neural network
was trained with a physics-based regularization term incorporating the spoiled
gradient echo equation that describes variable-flip angle (VFA) data.
Fully-sampled VFA k-space data were retrospectively accelerated by factors of
R={8,12,18,36} and reconstructed with ConvDecoder (CD), ConvDecoder with the
proposed regularization (CD+r), locally low-rank (LR) reconstruction, and
compressed sensing with L1-wavelet regularization (L1). Final images from CD+r
training were evaluated at the \emph{argmin} of the regularization loss;
whereas the CD, LR, and L1 reconstructions were chosen optimally based on
ground truth data. The performance measures used were the normalized root-mean
square error, the concordance correlation coefficient (CCC), and the structural
similarity index (SSIM). The CD+r reconstructions, chosen using the stopping
condition, yielded SSIMs that were similar to the CD (p=0.47) and LR SSIMs
(p=0.95) across R and that were significantly higher than the L1 SSIMs
(p=0.04). The CCC values for the CD+r T1 maps across all R and subjects were
greater than those corresponding to the L1 (p=0.15) and LR (p=0.13) T1 maps,
respectively. For R > 12 (<4.2 minutes scan time), L1 and LR T1 maps exhibit a
loss of spatially refined details compared to CD+r. We conclude that the use of
an untrained neural network together with a physics-based regularization loss
shows promise as a measure for determining the optimal stopping point in
training without relying on fully-sampled ground truth data.Comment: 45 pages, 7 figures, 2 Tables, supplementary material included (10
figures, 4 tables
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