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Journal articleGrech-Sollars M, Vaqas B, Thompson G, et al., 2015,
NIMG-30an MRS and PET guided biopsy tool for ultrasound-based intra-operative neuro-navigational systems
, Neuro-Oncology, Vol: 17, Pages: v160.2-v160, ISSN: 1522-8517 -
Journal articleAbraham CL, Bangerter NK, McGavin LS, et al., 2015,
Accuracy of 3D dual echo steady state (DESS) MR arthrography to quantify acetabular cartilage thickness
, Journal of Magnetic Resonance Imaging, Vol: 42, Pages: 1329-1338, ISSN: 1053-1807<jats:sec><jats:title>Purpose</jats:title><jats:p>To deploy and quantify the accuracy of 3D dual echo steady state (DESS) MR arthrography with hip traction to image acetabular cartilage. Clinical magnetic resonance imaging (MRI) sequences used to image hip cartilage often have reduced out‐of‐plane resolution and may lack adequate signal‐to‐noise to image cartilage.</jats:p></jats:sec><jats:sec><jats:title>Materials and Methods</jats:title><jats:p>Saline was injected into four cadaver hips placed under traction. 3D DESS MRI scans were obtained before and after cores of cartilage were harvested from the acetabulum; the two MRIs were spatially aligned to reference core positions. The thickness of cartilage cores was measured under microscopy to serve as the reference standard. 3D reconstructions of cartilage and subchondral bone were generated using automatic and semiautomatic image segmentation. Cartilage thickness estimated from the 3D reconstructions was compared to physical measurements using Bland–Altman plots.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>As revealed by the automatic segmentation mask, saline imbibed the joint space throughout the articulating surface, with the exception of the posteroinferior region in two hips. Locations where air bubbles were introduced and regions of suspected low density bone disrupted an otherwise smooth automatic segmentation mask. Automatic and semiautomatic segmentation yielded a bias ± repeatability coefficient (95% limits of agreement) of 0.10 ± 0.51 mm (−0.41 to 0.61 mm) and 0.06 ± 0.43 mm (−0.37 to 0.49 mm), respectively.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Cartilage thickness can be estimated to within ∼0.5 mm of the physical value with 95% conf
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Conference paperOrdidge K, Grech-Sollars M, Honeyfield L, et al., 2015,
18F-FLUOROMETHYLCHOLINE (18F-FMC) PET/CT AND MAGNETIC RESONANCE SPECTROSCOPY (MRS) IMAGING AND TISSUE BIOMARKERS OF CELL MEMBRANE TURNOVER IN PRIMARY BRAIN GLIOMAS-A PILOT STUDY
, Meeting of the British-Neuro-Oncology-Society (BNOS), Publisher: OXFORD UNIV PRESS INC, Pages: 5-5, ISSN: 1522-8517- Author Web Link
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- Citations: 1
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Journal articleWang H, Bangerter NK, Park DJ, et al., 2015,
Comparison of centric and reverse‐centric trajectories for highly accelerated three‐dimensional saturation recovery cardiac perfusion imaging
, Magnetic Resonance in Medicine, Vol: 74, Pages: 1070-1076, ISSN: 0740-3194<jats:sec><jats:title>Purpose</jats:title><jats:p>Highly undersampled three‐dimensional (3D) saturation‐recovery sequences are affected by k‐space trajectory since the magnetization does not reach steady state during the acquisition and the slab excitation profile yields different flip angles in different slices. This study compares centric and reverse‐centric 3D cardiac perfusion imaging.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>An undersampled (98 phase encodes) 3D ECG‐gated saturation‐recovery sequence that alternates centric and reverse‐centric acquisitions each time frame was used to image phantoms and in vivo subjects. Flip angle variation across the slices was measured, and contrast with each trajectory was analyzed via Bloch simulation.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Significant variations in flip angle were observed across slices, leading to larger signal variation across slices for the centric acquisition. In simulation, severe transient artifacts were observed when using the centric trajectory with higher flip angles, placing practical limits on the maximum flip angle used. The reverse‐centric trajectory provided less contrast, but was more robust to flip angle variations.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Both of the k‐space trajectories can provide reasonable image quality. The centric trajectory can have higher CNR, but is more sensitive to flip angle variation. The reverse‐centric trajectory is more robust to flip angle variation. Magn Reson Med 74:1070–1076, 2015. © 2014 Wiley Periodicals, Inc.</jats:p></jats:sec>
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Journal articleLally P, PAULIAH S, MONTALDO P, et al., 2015,
Magnetic Resonance Biomarkers in Neonatal Encephalopathy (MARBLE): A Prospective Multi-Country Study
, BMJ Open, Vol: 5, ISSN: 2044-6055Despite cooling adverse outcomes are seen in upto half of the surviving infants after neonatal encephalopathy. A number of novel adjunct drug therapies with cooling have been shown to be highly neuroprotective in animal studies, and are currently awaiting clinical translation. Riggorous evaluation of these therapies in phase II trials using surrogate magnetic resonance biomarkers may speed up thier bench to bedside translation. A recent systematic review of single centres studies have suggested that Magnetic resonance spectroscopy biomarkers offers the best promise, however the prognostic accuracy of these biomarkers in cooled encephalopathic babies in a multicentre setting using different MR scan makes is not known.
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Journal articleIbrahim T, Few K, Greenwood R, et al., 2015,
'Feed and wrap' or sedate and immobilise for neonatal brain MRI?
, ARCHIVES OF DISEASE IN CHILDHOOD-FETAL AND NEONATAL EDITION, Vol: 100, Pages: F465-U95, ISSN: 1359-2998- Author Web Link
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- Citations: 14
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Journal articleSoo A, Taha S, Lally P, et al., 2015,
Assessment of optic nerve development using post-mortem Magnetic Resonance Imaging (MRI) in fetuses and newborns
, Prenatal Diagnosis, Vol: 35, Pages: 1262-1264, ISSN: 0197-3851What's already known about this topic?Biometric studies of fetal orbit and lens development have been shown to correlate with gestational age.No available data on optic nerve measurements in fetuses/neonates.What does this study add?Normal fetal/neonatal optic nerve diameter measurements for gestational age as measured on post‐mortem MRI scans.
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Journal articleArthurs OJ, Thayyil S, Pauliah SS, et al., 2015,
Diagnostic accuracy and limitations of post-mortem MRI for neurological abnormalities in fetuses and children
, CLINICAL RADIOLOGY, Vol: 70, Pages: 872-880, ISSN: 0009-9260- Author Web Link
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- Citations: 73
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Journal articleMontaldo P, Chaban B, Lally PJ, et al., 2015,
Quantification of ante-mortem hypoxic ischemic brain injury by post-mortem cerebral magnetic resonance imaging in neonatal encephalopathy
, European Journal of Paediatric Neurology, Vol: 19, Pages: 665-671, ISSN: 1090-3798Post-mortem (PM) magnetic resonance imaging (MRI) is increasingly used as an alternative to conventional autopsy in babies dying from neonatal encephalopathy. However, the confounding effect of post-mortem changes on the detection of ante-mortem ischemic injury is unclear. We examined whether quantitative MR measurements can accurately distinguish ante-mortem ischemic brain injury from artifacts using post-mortem MRI.Methods:We compared PM brain MRI (1.5 T Siemens, Avanto) in 7 infants who died with neonatal encephalopathy (NE) of presumed hypoxic-ischemic origin with 7 newborn infants who had sudden unexplained neonatal death (SUND controls) without evidence of hypoxic-ischemic brain injury at autopsy. We measured apparent diffusion coefficients (ADCs), T1-weighted signal intensity ratios (SIRs) compared to vitreous humor and T2 relaxation times from 19 predefined brain areas typically involved in neonatal encephalopathy.Results:There were no differences in mean ADC values, SIRs on T1-weighted images or T2 relaxation times in any of the 19 predefined brain areas between NE and SUND infants. All MRI images showed loss of cortical gray/white matter differentiation, loss of the normal high signal intensity (SI) in the posterior limb of the internal capsule on T1-weighted images, and high white matter SI on T2-weighted images.Conclusion:Normal post-mortem changes may be easily mistaken for ante-mortem ischemic injury, and current PM MRI quantitative assessment cannot reliably distinguish these. These findings may have important implications for appropriate interpretation of PM imaging findings, especially in medico-legal practice.
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Journal articleYang G, Jones TL, Howe FA, et al., 2015,
Morphometric model for discrimination between glioblastoma multiforme and solitary metastasis using three-dimensional shape analysis
, Magnetic Resonance in Medicine, Vol: 75, Pages: 2505-2516, ISSN: 0740-3194Purpose:Glioblastoma multiforme (GBM) and brain metastasis (MET) are the most common intra-axial brain neoplasms in adults and often pose a diagnostic dilemma using standard clinical MRI. These tumor types require different oncological and surgical management, which subsequently influence prognosis and clinical outcome.Methods:Here, we hypothesize that GBM and MET possess different three-dimensional (3D) morphological attributes based on their physical characteristics. A 3D morphological analysis was applied on the tumor surface defined by our diffusion tensor imaging (DTI) segmentation technique. It segments the DTI data into clusters representing different isotropic and anisotropic water diffusion characteristics, from which a distinct surface boundary between healthy and pathological tissue was identified. Morphometric features of shape index and curvedness were then computed for each tumor surface and used to build a morphometric model of GBM and MET pathology with the goal of developing a tumor classification method based on shape characteristics.Results:Our 3D morphometric method was applied on 48 untreated brain tumor patients. Cross-validation resulted in a 95.8% accuracy classification with only two shape features needed and that can be objectively derived from quantitative imaging methods.Conclusion:The proposed 3D morphometric analysis framework can be applied to distinguish GBMs from solitary METs.
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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