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BMC Medical Imaging

, 12:30

First Online: 11 October 2012Received: 21 December 2011Accepted: 02 October 2012

Abstract

BackgroundDiffusion tensor imaging DTI is increasingly used in various diseases as a clinical tool for assessing the integrity of the brain’s white matter. Reduced fractional anisotropy FA and an increased apparent diffusion coefficient ADC are nonspecific findings in most pathological processes affecting the brain’s parenchyma. At present, there is no gold standard for validating diffusion measures, which are dependent on the scanning protocols, methods of the softwares and observers. Therefore, the normal variation and repeatability effects on commonly-derived measures should be carefully examined.

MethodsThirty healthy volunteers mean age 37.8 years, SD 11.4 underwent DTI of the brain with 3T MRI. Region-of-interest ROI -based measurements were calculated at eleven anatomical locations in the pyramidal tracts, corpus callosum and frontobasal area. Two ROI-based methods, the circular method CM and the freehand method FM, were compared. Both methods were also compared by performing measurements on a DTI phantom. The intra- and inter-observer variability coefficient of variation, or CV% and repeatability intra-class correlation coefficient, or ICC were assessed for FA and ADC values obtained using both ROI methods.

ResultsThe mean FA values for all of the regions were 0.663 with the CM and 0.621 with the FM. For both methods, the FA was highest in the splenium of the corpus callosum. The mean ADC value was 0.727 ×10 mm-s with the CM and 0.747 ×10 mm-s with the FM, and both methods found the ADC to be lowest in the corona radiata. The CV percentages of the derived measures were < 13% with the CM and < 10% with the FM. In most of the regions, the ICCs were excellent or moderate for both methods. With the CM, the highest ICC for FA was in the posterior limb of the internal capsule 0.90, and with the FM, it was in the corona radiata 0.86. For ADC, the highest ICC was found in the genu of the corpus callosum 0.93 with the CM and in the uncinate fasciculus 0.92 with FM.

ConclusionsWith both ROI-based methods variability was low and repeatability was moderate. The circular method gave higher repeatability, but variation was slightly lower using the freehand method. The circular method can be recommended for the posterior limb of the internal capsule and splenium of the corpus callosum, and the freehand method for the corona radiata.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2342-12-30 contains supplementary material, which is available to authorized users.

Antti Brander, Pertti Ryymin, Juha Öhman, Seppo Soimakallio, Mika Helminen, Prasun Dastidar and Hannu Eskola contributed equally to this work.

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Autor: Ullamari Hakulinen - Antti Brander - Pertti Ryymin - Juha Öhman - Seppo Soimakallio - Mika Helminen - Prasun Dastidar - Ha

Fuente: https://link.springer.com/







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