Terence J T Norton, Marcelo Pereyra, Michael J Knight, Bryony M McGarry, Kimmo T Jokivarsi, Olli H J Gröhn, Risto A Kauppinen
{"title":"Stroke Onset Time Determination Using MRI Relaxation Times without Non-Ischaemic Reference in A Rat Stroke Model.","authors":"Terence J T Norton, Marcelo Pereyra, Michael J Knight, Bryony M McGarry, Kimmo T Jokivarsi, Olli H J Gröhn, Risto A Kauppinen","doi":"10.3233/BSI-160155","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Objective timing of stroke in emergency departments is expected to improve patient stratification. Magnetic resonance imaging (MRI) relaxations times, T<sub>2</sub> and T<sub>1<i>ρ</i></sub> , in abnormal diffusion delineated ischaemic tissue were used as proxies of stroke time in a rat model.</p><p><strong>Methods: </strong>Both 'non-ischaemic reference'-dependent and -independent estimators were generated. Apparent diffusion coefficient (ADC), T<sub>2</sub> and T<sub>1<i>ρ</i></sub> , were sequentially quantified for up to 6 hours of stroke in rats (n = 8) at 4.7T. The ischaemic lesion was identified as a contiguous collection of voxels with low ADC. T<sub>2</sub> and T<sub>1<i>ρ</i></sub> in the ischaemic lesion and in the contralateral non-ischaemic brain tissue were determined. Differences in mean MRI relaxation times between ischaemic and non-ischaemic volumes were used to create reference-dependent estimator. For the reference-independent procedure, only the parameters associated with log-logistic fits to the T<sub>2</sub> and T<sub>1<i>ρ</i></sub> distributions within the ADC-delineated lesions were used for the onset time estimation.</p><p><strong>Result: </strong>The reference-independent estimators from T<sub>2</sub> and T<sub>1<i>ρ</i></sub> data provided stroke onset time with precisions of ±32 and ±27 minutes, respectively. The reference-dependent estimators yielded respective precisions of ±47 and ±54 minutes.</p><p><strong>Conclusions: </strong>A 'non-ischaemic anatomical reference'-independent estimator for stroke onset time from relaxometric MRI data is shown to yield greater timing precision than previously obtained through reference-dependent procedures.</p>","PeriodicalId":44239,"journal":{"name":"Biomedical Spectroscopy and Imaging","volume":null,"pages":null},"PeriodicalIF":0.3000,"publicationDate":"2017-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.3233/BSI-160155","citationCount":"13","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biomedical Spectroscopy and Imaging","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3233/BSI-160155","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"SPECTROSCOPY","Score":null,"Total":0}
引用次数: 13
Abstract
Background: Objective timing of stroke in emergency departments is expected to improve patient stratification. Magnetic resonance imaging (MRI) relaxations times, T2 and T1ρ , in abnormal diffusion delineated ischaemic tissue were used as proxies of stroke time in a rat model.
Methods: Both 'non-ischaemic reference'-dependent and -independent estimators were generated. Apparent diffusion coefficient (ADC), T2 and T1ρ , were sequentially quantified for up to 6 hours of stroke in rats (n = 8) at 4.7T. The ischaemic lesion was identified as a contiguous collection of voxels with low ADC. T2 and T1ρ in the ischaemic lesion and in the contralateral non-ischaemic brain tissue were determined. Differences in mean MRI relaxation times between ischaemic and non-ischaemic volumes were used to create reference-dependent estimator. For the reference-independent procedure, only the parameters associated with log-logistic fits to the T2 and T1ρ distributions within the ADC-delineated lesions were used for the onset time estimation.
Result: The reference-independent estimators from T2 and T1ρ data provided stroke onset time with precisions of ±32 and ±27 minutes, respectively. The reference-dependent estimators yielded respective precisions of ±47 and ±54 minutes.
Conclusions: A 'non-ischaemic anatomical reference'-independent estimator for stroke onset time from relaxometric MRI data is shown to yield greater timing precision than previously obtained through reference-dependent procedures.
期刊介绍：
Biomedical Spectroscopy and Imaging (BSI) is a multidisciplinary journal devoted to the timely publication of basic and applied research that uses spectroscopic and imaging techniques in different areas of life science including biology, biochemistry, biotechnology, bionanotechnology, environmental science, food science, pharmaceutical science, physiology and medicine. Scientists are encouraged to submit their work for publication in the form of original articles, brief communications, rapid communications, reviews and mini-reviews. Techniques covered include, but are not limited, to the following: • Vibrational Spectroscopy (Infrared, Raman, Teraherz) • Circular Dichroism Spectroscopy • Magnetic Resonance Spectroscopy (NMR, ESR) • UV-vis Spectroscopy • Mössbauer Spectroscopy • X-ray Spectroscopy (Absorption, Emission, Photoelectron, Fluorescence) • Neutron Spectroscopy • Mass Spectroscopy • Fluorescence Spectroscopy • X-ray and Neutron Scattering • Differential Scanning Calorimetry • Atomic Force Microscopy • Surface Plasmon Resonance • Magnetic Resonance Imaging • X-ray Imaging • Electron Imaging • Neutron Imaging • Raman Imaging • Infrared Imaging • Terahertz Imaging • Fluorescence Imaging • Near-infrared spectroscopy.
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