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Updated: May 17, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Repeatability and variation of region-of-interest methods using quantitative diffusion tensor MR imaging of the brain
Ullamari Hakulinen1, Antti Brander, Pertti Ryymin
1Department of Radiology, Medical Imaging Center of Pirkanmaa Hospital District, Teiskontie 35 PL 2000, 33521, Tampere, Finland. ullamari.hakulinen@pshp.fi
Background:
Diffusion 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.
Methods:
Thirty 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.
Results:
The 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 ×10-3 mm2/s with the CM and 0.747 ×10-3 mm2/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.
Conclusions:
With 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.
Insights
This study compared two region-of-interest methods for diffusion tensor imaging (DTI) analysis in healthy volunteers. Both methods showed low variability and moderate repeatability for fractional anisotropy (FA) and apparent diffusion coefficient (ADC) measures.
Area of Science:
- Neuroimaging
- Radiology
- Biomedical Engineering
Background:
- Diffusion tensor imaging (DTI) is vital for assessing white matter integrity in various neurological conditions.
- Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) are key DTI metrics, but their interpretation is limited by variability and lack of a gold standard.
- Understanding normal variation and repeatability is crucial for accurate DTI interpretation in clinical settings.
Purpose of the Study:
- To compare the variability and repeatability of two region-of-interest (ROI) based methods for calculating DTI measures.
- To assess the performance of the circular method (CM) and freehand method (FM) for FA and ADC quantification.
- To determine the optimal ROI method for specific white matter tracts.
Main Methods:
- Thirty healthy volunteers underwent 3T MRI DTI scans.
- FA and ADC values were calculated using both circular (CM) and freehand (FM) ROI methods at eleven anatomical locations.
- Intra- and inter-observer variability (CV%) and repeatability (ICC) were assessed for both methods, and compared against a DTI phantom.
Main Results:
- Both CM and FM demonstrated low variability (<13% CV) and moderate to excellent repeatability (ICC).
- FA values were higher with CM (0.663) than FM (0.621); ADC values were slightly higher with FM (0.747 ×10-3 mm2/s) than CM (0.727 ×10-3 mm2/s).
- Specific regions showed excellent repeatability for both methods, with CM excelling in the posterior limb of the internal capsule and FM in the corona radiata for FA.
Conclusions:
- Both circular and freehand ROI methods offer low variability and moderate repeatability for DTI measures.
- The circular method demonstrated higher repeatability, while the freehand method showed slightly lower variation.
- The circular method is recommended for the posterior limb of the internal capsule and splenium of the corpus callosum, while the freehand method is suitable for the corona radiata.
