Radiology - Research Publications

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    Normative retrobulbar measurements of the optic nerve using ultra high field magnetic resonance imaging
    Nguyen, BN ; Cleary, JO ; Glarin, R ; Kolbe, SC ; Moffat, BA ; Ordidge, RJ ; Bui, BV ; McKendrick, AM (Association for Research in Vision and Ophthalmology, 2019-07-01)
    Purpose : We exploit the improved spatial resolution and signal-to-noise gain of ultra high field (7T) magnetic resonance imaging (MRI) with a dedicated eye coil for more accurate morphometric measurements of the optic nerve ~2.5mm behind the globe. Methods : Coronal T2-weighted oblique images (TR=2000ms, TE=64ms, FOV=155mm, matrix=384 x 384, slice thickness=0.7mm, scan time=2’34”) through the optic nerve were obtained in 21 healthy adults (20-41 years, 11 emmetropes: +0.75 to -0.50D, 10 myopes: -4.5 to -12D) using a 7T Siemens Magnetom scanner (Erlangen, Germany) and 6-channel eye coil (MRI.TOOLS GmbH, Berlin, Germany). Horizontal and vertical outer diameter of the optic nerve, subarachnoid space (fluid gap) and optic sheath were measured by hand using biomedical imaging software (OsiriX, Pixmeo, Switzerland) (Figure). Significant motion artefacts were avoided with customised fixation and preparation techniques. Results : Horizontal and vertical measurements were similar so were averaged. Right and left eye diameters did not differ and were highly correlated (optic nerve: Pearson r=0.9, p<0.001; fluid gap: r=0.8, p<0.001; optic sheath: r=0.7, p<0.001); hence we report left eye data only. Optic nerve diameter (average of horizontal and vertical diameters) ranged from 2.8-4.1mm in emmetropes and 1.5-4.2mm in myopes and correlated with refractive error (Spearman r=0.46, p=0.04). Similarly, fluid gap diameter (emmetropes: 3.6-5.5mm, myopes: 2.5-5.6mm), but not optic sheath diameter (emmetropes: 4.5-6.8mm, myopes: 4.2-6.8mm), correlated with refractive error (r=0.47, p=0.03). Conclusions : Ultra high field MRI with thinner slices enables more accurate demarcation of the optic nerve, surrounding fluid/subarachnoid space and optic sheath without overlapping of neighbouring anatomy (minimal partial volume artefact). Our 7T MRI-derived normative measurements of optic nerve, fluid gap and sheath diameter are comparable with published reports in healthy observers obtained at conventional MRI magnetic fields (1.5-3T). Our findings suggest a trend for retrobulbar optic nerve and subarachnoid space, but not optic sheath, to be smaller in high myopes.
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    Cerebrovascular disease, Alzheimer's disease biomarkers and longitudinal cognitive decline
    Yates, PA ; Villemagne, VL ; Ames, D ; Masters, CL ; Martins, RN ; Desmond, P ; Burnham, S ; Maruff, P ; Ellis, KA ; Rowe, CC (WILEY-BLACKWELL, 2016-06-01)
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    Objective speech marker correlates with clinical scores in non-dysarthric MS
    Noffs, G ; Boonstra, F ; Kolbe, S ; Perera, T ; Shanahan, C ; Evans, A ; Butzkueven, H ; Vogel, A ; Van der Walt, A (SAGE PUBLICATIONS LTD, 2017-10-01)
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    Pathophysiology of MS tremor: an fMRI study
    Boonstra, FMC ; Noffs, G ; Perera, T ; Shanahan, CJ ; Vogel, AP ; Evans, A ; Butzkueven, H ; van der Walt, A ; Kolbe, SC (SAGE PUBLICATIONS LTD, 2017-10-01)
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    Subclinical speech signs correlate with MS disease severity and differentiates patients with and without clinical cerebellar dysfunction
    Noffs, G ; Boonstra, F ; Perera, T ; Kolbe, S ; Shanahan, C ; Evans, A ; Butzkueven, H ; Vogel, A ; van der Walt, A (SAGE PUBLICATIONS LTD, 2017-10-01)
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    Objective analysis of speech correlates with disease severity in Multiple Sclerosis and differentiates groups with and without upper limb tremor
    Noffs, G ; Boonstra, F ; Perera, T ; Kolbe, SC ; Shanahan, CJ ; Evans, A ; Butzkueven, H ; Vogel, AP ; van der Walt, A (SAGE PUBLICATIONS LTD, 2017-11-01)
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    Pathophysiology of MS tremor: an fMRI study
    Boonstra, F ; Noffs, G ; Perera, T ; Shanahan, C ; Vogel, A ; Evans, A ; Butzkueven, H ; van der Walt, A ; Kolbe, S (SAGE PUBLICATIONS LTD, 2017-11-01)
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    Validation of the tremor biomechanics analysis laboratory (TREMBAL) software in MS tremor
    Van der Walt, A ; Boonstra, FMC ; Yohanandan, SAC ; Vogel, AP ; Kolbe, SC ; Ly, J ; Noffs, G ; Butzkueven, H ; Evans, AH ; Perera, T (SAGE PUBLICATIONS LTD, 2016-09-01)
    Type: Poster Abstract Category: Clinical aspects of MS - Clinical assessment tools Background: Tremor in MS (MST) is difficult to treat and the development of new interventions is limited by the absence of universal measuring systems. At present, therapeutic outcomes are measured by a variety of clinical rating scales that are subjective and lack sufficient sensitivity. With increasing use of interventional treatments such as Botulinum toxin injections or Deep Brain Stimulation for MST, it has become critical to develop precise measurement instruments. Objective: To clinically validate the TREMBAL software in MST. Methods: TREMBAL (Bionics Institute, Melbourne, Australia) utilises an electromagnetic motion tracker (Ascension, Vermont, US) to acquire absolute displacements and rotations of a tremulous body part. Tremor was recorded bilaterally from four locations (second phalanx of the middle finger, wrist dorsum, forearm and upper arm) in five positions (hands resting on lap, arms outstretched in front, finger-nose, batwing static and batwing action). Tremor exercises were video recorded (GoPro Hero3, GoPro Inc., San Mateo, California) and rated by two experts using the 5-point Unified Tremor Rating Assessment (UTRA) scale where 0=no tremor and 4=severe. TREMBAL tremor displacements (measured in units of millimetres) were averaged and log transformed to match the distribution of clinical ratings. Data were pooled across exercises. Congruence between TREMBAL measures and mean clinical ratings was explored using regression analysis and Pearson´s correlation. Results: We assessed ten MST patients over 6 months and rated 200 videos. The median pooled UTRA score was 0.5 (interquartile range 0, 1.5). The average TREMBAL recorded tremor displacement was 1.65 mm (standard deviation 2.1). A strong correlation between UTRA scores and log transformed TREMBAL displacement was found, r = 0.749, p< 0.001. Conclusions: TREMBAL measurements are highly accurate when compared to clinical measurements. While other objective tremor measures exist, only a few have been benchmarked specifically against MST clinical ratings. The validation of an objective, 3 dimensional tremor measurement system provides real-time tremor severity measurements for clinicians and can be applied in clinical trials of putative therapies for MST.