| 1. |
- Gard, Anna, et al.
(author)
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Widespread White Matter Abnormalities in Concussed Athletes Detected by 7T Diffusion Magnetic Resonance Imaging
- 2024
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In: Journal of Neurotrauma. - : Mary Ann Liebert. - 0897-7151 .- 1557-9042. ; 41:13-14, s. 1533-1549
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Journal article (peer-reviewed)abstract
- Sports-related concussions may cause white matter injuries and persistent post-concussive symptoms (PPCS). We hypothesized that athletes with PPCS would have neurocognitive impairments and white matter abnormalities that could be revealed by advanced neuroimaging using ultra-high field strength diffusion tensor (DTI) and diffusion kurtosis (DKI) imaging metrics and cerebrospinal fluid (CSF) biomarkers. A cohort of athletes with PPCS severity limiting the ability to work/study and participate in sport school and/or social activities for ≥6 months completed 7T magnetic resonance imaging (MRI) (morphological T1-weighed volumetry, DTI and DKI), extensive neuropsychological testing, symptom rating, and CSF biomarker sampling. Twenty-two athletes with PPCS and 22 controls were included. Concussed athletes performed below norms and significantly lower than controls on all but one of the psychometric neuropsychology tests. Supratentorial white and gray matter, as well as hippocampal volumes did not differ between concussed athletes and controls. However, of the 72 examined white matter tracts, 16% of DTI and 35% of DKI metrics (in total 28%) were significantly different between concussed athletes and controls. DKI fractional anisotropy and axial kurtosis were increased, and DKI radial diffusivity and radial kurtosis decreased in concussed athletes when compared with controls. CSF neurofilament light (NfL; an axonal injury marker), although not glial fibrillary acidic protein, correlated with several diffusion metrics. In this first 7T DTI and DKI study investigating PPCS, widespread microstructural alterations were observed in the white matter, correlating with CSF markers of axonal injury. More white matter changes were observed using DKI than using DTI. These white matter alterations may indicate persistent pathophysiological processes following concussion in sport.
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| 2. |
- Grip, Helena, et al.
(author)
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Three dimensional kinematic analyses of finger movement control and association to brain activity responses : A pilot study on healthy individuals
- 2017
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In: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 57, s. 355-
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Journal article (peer-reviewed)abstract
- Introduction: An increased knowledge of how the brain control finger movements give us keys to understand the recovery of motor function after a brain injury. This knowledge is crucial for the development of reliable and valid assessment methods in the clinical evaluation of hand function.Research question: How are individual finger movements represented in the brain? Investigating the associations between kinematics and brain activity responses in healthy individuals.Methods: Keeping the others still. Finger movements were performed lying in the MR scanner in order to register brain activity response during the task. Optoelectronic cameras simultaneously monitored the positions of reflective markers affixed to each finger. The marker position data were used to calculate each finger's movement frequency (MF), movement independence (“Individuation Index”, II), stationary ability (Stationarity Index, SI)[1][1]. fMRI data was analyzed by contrasting the finger movements against its active rest.Results: Preliminary analyses showed that (1) the finger movements primarily activate sensorimotor areas in the contralateral hemisphere (Fig. 1A), (2) that use of kinematic parameters in the fMRI analyses improved spatial specificity and (3) II engage a number of cortical areas, while MF engage fewer areas (Fig. 1B–D). Further analyses will further explore activations maps for each individual finger.Discussion: The inclusion of movement parameters in the fMRI analyses improves the specificity in the derived activation map, increasing the interpretability of the neural correlates of movement control. This advancement carries the promise for the development of better assessment methods of the recovery of function post-stroke with usability in rehabilitation practices.
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| 3. |
- Khodadad, Davood, 1985-, et al.
(author)
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B-spline based free form deformation thoracic non-rigid registration of CT and PET images
- 2011
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In: International Conference on Graphic and Image Processing (ICGIP 2011). - : SPIE - International Society for Optical Engineering. ; 8285
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Conference paper (peer-reviewed)abstract
- Accurate attenuation correction of emission data is mandatory for quantitative analysis of PET images. One of the main concerns in CT-based attenuation correction(CTAC) of PET data in multimodality PET/CT imaging is misalignment between PET and CT images. The aim of this study, is to proposed a hybrid method which is simple, fast and accurate, for registration of PET and CT data which affected from respiratory motion in order to improve the quality of CTAC. The algorithm is composed of three methods: First, using B-spline Free Form Deformation to describe both images and deformation field. Then applying a pre-filtering on both PET and CT images before segmentation of structures in order to reduce the respiratory related attenuation correction artifacts of PET emission data. In this approach, B-spline using FFD provide more accurate adaptive transformation to align the images, and structure constraints obtained from prefiltering applied to guide the algorithm to be more fast and accurate. Also it helps to reduce the radiation dose in PET/CT by avoiding repetition of CT imaging. These advances increase the potential of the method for routine clinical application.
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| 4. |
- Kruse, Johan, et al.
(author)
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Scrutinized with inadequate control and support : Interns' experiences communicating with and writing referrals to hospital radiology departments - A qualitative study
- 2016
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In: Radiography. - : Elsevier BV. - 1078-8174 .- 1532-2831. ; 22:4, s. 313-318
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Journal article (peer-reviewed)abstract
- Introduction: Interns' experiences communicating with and writing referrals to hospital radiology departments are important for patient safety, image quality, and decision-making in the diagnostic process. Understanding roles within the department and in the diagnostic process is important for communication. This study aimed to describe interns' experiences communicating with and writing referrals to their hospital's radiology department. Method: A qualitative study design was used. Data was collected from focus discussions with ten interns in three focus groups in Northern Sweden during 2012. The data were subjected to qualitative content analysis. Results: One theme, "a feeling of being scrutinized and lacking control", was identified in the final categories. The interns experienced that the radiology department placed high demands on them and desired more diagnostic skills training, resources and feedback. The interns suggested the following improvements: enhanced dialogue and feedback, improved education, handy guidelines, and practice writing referrals. Conclusion: Interns need more feedback from, and dialogue with, members of the Department of Radiology. They also need more knowledge of referral guidelines, appropriateness criteria and more practice to develop their knowledge and skill for writing referrals. They describe feelings of inadequate support and feel scrutinized in demanding work conditions and need more collaboration. They also need more time and more control of radiology outcomes, and they are eager to learn.
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| 5. |
- Gard, Anna, et al.
(author)
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Post-Concussive Vestibular Dysfunction Is Related to Injury to the Inferior Vestibular Nerve
- 2022
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In: Journal of Neurotrauma. - : Mary Ann Liebert Inc. - 0897-7151 .- 1557-9042. ; 39:11-12
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Journal article (peer-reviewed)abstract
- Symptoms of vestibular dysfunction such as dizziness and vertigo are common after sports-related concussions (SRC) and associated with a worse outcome and a prolonged recovery. Vestibular dysfunction after SRC can be because of an impairment of the peripheral or central neural parts of the vestibular system. The aim of the present study was to establish the cause of vestibular impairment in athletes with SRC who have persisting post-concussive symptoms (PPCS). We recruited 42 participants-21 athletes with previous SRCs and PPCS >= 6 months and 21 healthy athletic age- and sex-matched controls-who underwent symptom rating, a detailed test battery of vestibular function and 7T magnetic resonance imaging with diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) of cerebellar white matter tracts, and T1-weighted imaging for cerebellar volumetrics. Vestibular dysfunction was observed in 13 SRC athletes and three controls (p = 0.001). Athletes with vestibular dysfunction reported more pronounced symptoms on the Dizziness Handicap Inventory (DHI; p < 0.001) and the Hospital Anxiety and Depression Scale (HADS; p < 0.001). No significant differences in DTI metrics were found, while in DKI two metrics were observed in the superior and/or inferior cerebellar tracts. Cerebellar gray and white matter volumes were similar in athletes with SRC and controls. Compared with controls, pathological video head impulse test results (vHIT; p < 0.001) and cervical vestibular evoked myogenic potentials (cVEMP; p = 0.002) were observed in athletes with SRC, indicating peripheral vestibular dysfunction and specifically suggesting injury to the inferior vestibular nerve. In athletes with persisting symptoms after SRC, vestibular dysfunction is associated with injury to the inferior vestibular nerve.
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| 6. |
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| 7. |
- Rönnqvist, Louise, et al.
(author)
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Effects of twin-births on IQ, handedness, and brain volumes in 8-years-old preterm born twins and matched singletons: a pilot study
- 2016
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In: Developmental Medicine & Child Neurology. - : Wiley. - 0012-1622 .- 1469-8749. ; 58:S6, s. 57-
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Journal article (peer-reviewed)abstract
- Background: Children born preterm have a high prevalence of long-term cognitive and behavioral disturbances. Still, studies of how preterm-twin-births may effect brain maturation and thus, contribute to long-term effects on brain-behavioral development and functions are rare.Aim: To investigate whether brain volumes differ between twin (TPB) and singleton preterm born (SPB) and full-term born children (FTB) and associate to long-term cognitive and behavioral outcomes as well as to gestational age (GA), birth weight (BW) and head circumference (BHC) at birth.Method: A sample of 22 twin born preterm (Mean GA=32.1, BW=1781), 23 matched singletons preterm (Mean GA=31.8, BW=1751), and 22 full-term singletons were included. All children were investigated by means of their cognition functions (WISC-IV), handedness performance index and brain volumes (3 Tesla MRI) at early school ages (M=7.8y) in 40 children (9 TPB, 10 SPB, 21 FTB).Results: The FTB-children performed better than both TPB and SPB on cognitive performance, and showed higher IQ. Brain volumes, especially Gray matter were stronger associated with IQ in the twins. Furthermore it was found that the SPB singletons had smaller Total Brain volume and less Grey Matter than FTB. The twins showed a higher prevalence of non-right handedness associated to GA, than both SPB and FTB. Independently of birth status, GA, BW and BHC were found to correlate positively with IQ, Total Brain volume, and Gray-and White matter volumes.Conclusion: Discordant handedness in TPB children and associations to lower GA indicate effect of twin-births on early functional laterality. The overall associations found between low GA/BW and smaller BHC at birth in preterm born and associations with lower IQ and smaller brain volumes at 8-y indicate that a very preterm birth are a higher predictor for long-term effects on brain development and cognitive performance than twin-birth per se.
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| 8. |
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| 9. |
- Drake, Anna Maria, et al.
(author)
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Assessment of contractile and noncontractile components in human skeletal muscle by magnetic resonance imaging.
- 2002
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In: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 25:2, s. 251-258
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Journal article (peer-reviewed)abstract
- A magnetic resonance imaging (MRI) technique for the assessment of contractile and noncontractile components of human skeletal muscle is described, and the inter-rater and intra-rater test-retest reliability for repeated measurements from the same MR image are examined. Twenty cross-sectional MR images from the right lower leg were obtained from 30 healthy young men and women (mean age 24.1 years, SD 3.3). The anatomical cross-sectional area (aCSA; cm2), the cross-sectional area of noncontractile components (Noncon; cm2), the contractile cross-sectional area (cCSA = aCSA minus Noncon; cm2), and the relative amount of Noncon (%), of the ankle dorsiflexor muscle compartment were determined for each slice using a computer-based image analysis system. Reliability for repeated measurements of the slice with the largest aCSA for the 30 subjects was analyzed by two raters on two different occasions. Inter-rater reliability on both occasions, assessed by the intraclass correlation coefficient (ICC), was excellent for cCSA (ICC3.1 = 0.99) and Noncon (ICC(3.1)
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| 10. |
- Filippov, Andrei, et al.
(author)
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Dynamic properties of water in silicalite-1 powder
- 2012
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In: Magnetic Resonance Imaging. - : Elsevier BV. - 0730-725X .- 1873-5894. ; 30:7, s. 1022-1031
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Journal article (peer-reviewed)abstract
- Self-diffusion of D2O in partially filled silicalite-1 crystals was studied at 25 degrees C by H-2 nuclear magnetic resonance (NMR) with bipolar field gradient pulses and longitudinal Eddy-current-delay. For the first time, reliable experimental diffusion data for this system were obtained. Analysis of NMR diffusion decays revealed the presence of a continuous distribution of apparent self-diffusion coefficients (SDCs) of water, ranging from 10(-7) to similar to 10(-10) m(2)/s, which include values much higher and lower than that of bulk water (similar to 10(-9) m(2)/s) in liquid phase. The observed distribution of SDC changes with variation of the diffusion time in the range of 10-200 ms. A two-site Karger exchange model was successfully fitted to the data. Finally, the water distribution and exchange in silicalite-1 pores were described by taking into account (a) a gas-like phase in the zeolite pores, a gas-like phase in mesopores and an intercrystalline gas-like phase and (b) intercrystalline liquid droplets with intermediate exchange rate with the other phases. The other phases experience fast exchange on the NMR diffusion time scale. Diffusion coefficients and mean residence times of water in some of these states were estimated.
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