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Journal articleYang G, Nawaz T, Barrick T, et al., 2015,
Discrete Wavelet Transform Based Whole-Spectral and Sub-Spectral Analysis for Improved Brain Tumour Clustering using Single Voxel MR Spectroscopy
, IEEE Transactions on Biomedical Engineering, Vol: 62, Pages: 2860-2866, ISSN: 0018-9294Many approaches have been considered for automatic grading of brain tumours by means of pattern recognition with magnetic resonance spectroscopy (MRS). Providing an improved technique which can assist clinicians in accurately identifying brain tumour grades is our main objective. The proposed technique, which is based on the discrete wavelet transform (DWT) of whole-spectral or sub-spectral information of key metabolites, combined with unsupervised learning, inspects the separability of the extracted wavelet features from the MRS signal to aid the clustering. In total, we included 134 short echo time single voxel MRS spectra (SV MRS) in our study that cover normal controls, low grade and high grade tumours. The combination of DWT-based whole-spectral or sub-spectral analysis and unsupervised clustering achieved an overall clustering accuracy of 94.8% and a balanced error rate of 7.8%. To the best of our knowledge, it is the first study using DWT combined with unsupervised learning to cluster brain SV MRS. Instead of dimensionality reduction on SV MRS or feature selection using model fitting, our study provides an alternative method of extracting features to obtain promising clustering results.
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Journal articleBosaily AE-S, Parker C, Brown LC, et al., 2015,
PROMIS - Prostate MR imaging study: A paired validating cohort study evaluating the role of multi-parametric MRI in men with clinical suspicion of prostate cancer
, CONTEMPORARY CLINICAL TRIALS, Vol: 42, Pages: 26-40, ISSN: 1551-7144- Author Web Link
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- Citations: 84
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PatentYang G, Barrick T, Howe F, 2015,
Analysing MRI Data to Determine Tumour Type
, WO/2015/079235 -
Journal articleMontaldo P, Pauliah SS, Lally PJ, et al., 2015,
Cooling in a low-resource environment: Lost in translation
, SEMINARS IN FETAL & NEONATAL MEDICINE, Vol: 20, Pages: 72-79, ISSN: 1744-165X- Author Web Link
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- Citations: 54
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PatentYang G, Barrick T, Jones T, et al., 2015,
Analysing MRI Data to Determine Tumour Type
, WO/2015/040434 -
Journal articleGrech-Sollars M, Hales PW, Miyazaki K, et al., 2015,
Multi-centre reproducibility of diffusion MRI parameters for clinical sequences in the brain.
, NMR in Biomedicine, Vol: 28, Pages: 468-485, ISSN: 0952-3480The purpose of this work was to assess the reproducibility of diffusion imaging, and in particular the apparent diffusion coefficient (ADC), intra-voxel incoherent motion (IVIM) parameters and diffusion tensor imaging (DTI) parameters, across multiple centres using clinically available protocols with limited harmonization between sequences. An ice-water phantom and nine healthy volunteers were scanned across fives centres on eight scanners (four Siemens 1.5T, four Philips 3T). The mean ADC, IVIM parameters (diffusion coefficient D and perfusion fraction f) and DTI parameters (mean diffusivity MD and fractional anisotropy FA), were measured in grey matter, white matter and specific brain sub-regions. A mixed effect model was used to measure the intra- and inter-scanner coefficient of variation (CV) for each of the five parameters. ADC, D, MD and FA had a good intra- and inter-scanner reproducibility in both grey and white matter, with a CV ranging between 1% and 7.4%; mean 2.6%. Other brain regions also showed high levels of reproducibility except for small structures such as the choroid plexus. The IVIM parameter f had a higher intra-scanner CV of 8.4% and inter-scanner CV of 24.8%. No major difference in the inter-scanner CV for ADC, D, MD and FA was observed when analysing the 1.5T and 3T scanners separately. ADC, D, MD and FA all showed good intra-scanner reproducibility, with the inter-scanner reproducibility being comparable or faring slightly worse, suggesting that using data from multiple scanners does not have an adverse effect compared with using data from the same scanner. The IVIM parameter f had a poorer inter-scanner CV when scanners of different field strengths were combined, and the parameter was also affected by the scan acquisition resolution. This study shows that the majority of diffusion MRI derived parameters are robust across 1.5T and 3T scanners and suitable for use in multi-centre clinical studies and trials.
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Conference paperWang H, Bangerter NK, Chen L, et al., 2015,
Radial CAIPIRINHA for Rapid 6 Slice Myocardial Perfusion Without Magnetization Preparation
, ISMRM 23rd Annual Meeting & Exhibition -
Journal articleScott AD, Nielles-Vallespin S, Ferreira P, et al., 2015,
Improving the accuracy of cardiac DTI by averaging the complex data
, Journal of Cardiovascular Magnetic Resonance, Pages: 1-3, ISSN: 1097-6647 -
Journal articleMcGill LA, Scott AD, Ferreira P, et al., 2015,
Heterogeneity of diffusion tensor imaging measurements of fractional anisotropy and mean diffusivity in normal human hearts in vivo
, Journal of Cardiovascular Magnetic Resonance, Vol: 17, ISSN: 1097-6647 -
Journal articleKilner PJ, McCarthy K, Murillo M, et al., 2015,
Histology of human myocardial laminar microstructure and consideration of its cyclic deformations with respect to interpretation of in vivo cardiac diffusion tensor imaging
, Journal of Cardiovascular Magnetic Resonance, Pages: 1-3, ISSN: 1097-6647
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Contact
For enquiries about the MRI Physics Collective, please contact:
Mary Finnegan
Senior MR Physicist at the Imperial College Healthcare NHS Trust
Pete Lally
Assistant Professor in Magnetic Resonance (MR) Physics at Imperial College
Jan Sedlacik
MR Physicist at the Robert Steiner MR Unit, Hammersmith Hospital Campus