Publications by authors named "Timo J I Kurki"

2 Publications

  • Page 1 of 1

Diffusion parameters of the core of cingulum are associated with age-related ventricular enlargement: a diffusion tensor tractography study.

Neuroradiology 2018 Oct 8;60(10):1013-1018. Epub 2018 Aug 8.

Department of Neurology, University of Turku, 20014, Turku, Finland.

Purpose: To evaluate the influence of the size of lateral ventricles on diffusion parameters of the normal cingulate bundle.

Methods: Eighty normal subjects (17-55 years) underwent MRI at 3 T including diffusion tensor imaging. Superior (SC) and inferior (IC) cingulum were analyzed separately. Mean diffusivity (MD) and fractional anisotropy (FA) were measured by tractography at FA threshold 0.30; further diffusion parameters were analyzed by tractography-based core analysis in volumes of 3.0 cm/1.5 cm. The diffusion parameters were correlated with corresponding cross-sectional coronal areas of lateral ventricles. The analysis was performed also separately for young (17-34) and middle-aged (35-55) subjects.

Results: FA values did not correlate with ventricular size, but there was a weak negative correlation (r = - 0.225) between MD of SC and ventricular size. In all controls and in the older age group, ventricular size correlated positively with core FA of SC (r = 0.262/r = 0.391) and negatively with mean diffusivity (r = - 0.324/r = - 0.303) and radial diffusivity (λ: r = - 0.238/r = - 0.277; λ: r = - 0.353/r = - 0.424) of the core of SC. In the younger age group, only the mean diffusivity of SC correlated with ventricular size (r = - 0.273). Ventricular size was not associated with axial diffusivity. The core parameters of IC did not correlate with ventricular size.

Conclusion: Radial diffusivity of the core of cingulum decreases in age-dependent ventricular enlargement, which can be related to tissue compaction with stretching of axons and diminution of extracellular spaces. The phenomenon, which is reverse to the assumed effect of age-related myelin loss, can influence on DTI parameters in middle-aged subjects.
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October 2018

Diffusion tensor tractography of the uncinate fasciculus: pitfalls in quantitative analysis due to traumatic volume changes.

J Magn Reson Imaging 2013 Jul 3;38(1):46-53. Epub 2013 Jun 3.

Pulssi Medical Centre, Turku, Finland.

Purpose: To demonstrate the sensitivity of quantitative diffusion tensor tractography to traumatic injury of the uncinate fasciculus (UF), and to evaluate the effect of volume changes on the accuracy of quantitative analysis.

Materials And Methods: Diffusion tensor imaging (DTI) was performed at 3 T for 110 patients with traumatic brain injury (TBI) and 60 control subjects. Volume, mean diffusivity (MD), and mean fractional anisotropy (FA) of the UF were measured by means of tractography. The influence of FA threshold on mean FA values was determined and the values were further related to the tract volume.

Results: In patients with TBI, 16% of the volumes and 29% of the FA values were decreased and 25% of the MD values were increased (>2 SD from the mean of controls). Small tracts (6% of trajectories) often had normal mean FA, but low volume-related FA values. Large UFs often had decreased mean FA values, but normal volume-related central values (3% of trajectories).

Conclusion: Posttraumatic FA and MD changes and volume reductions are common in the tractography of UF. Trauma-induced volume changes can cause misleading whole-tract mean FA values. Therefore, additional volume-based analysis of the central part is beneficial for clinical assessment.
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July 2013