Reliability of the Freehand Region-of-Interest Method in Quantitative Cerebral Diffusion Tensor Imaging

Abstract

Background: Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique used for evaluating changes in the white matter in brain parenchyma. The reliability of quantitative DTI analysis is influenced by several factors, such as the imaging protocol, pre-processing and post-processing methods, and selected diffusion parameters. Of the post-processing methods, the region-of-interest (ROI) method is most widely used because it is found in commercial programs. The focus of our research was to study the reliability of the freehand ROI method using various intra- and inter-observer analyses.Methods: This study included 40 neurologically healthy participants who underwent diffusion MRI of the brain with a 3T scanner. The measurements were performed at nine different anatomical locations using a freehand ROI method. The data extracted from the ROIs included the regional mean values, intra- and inter-observer variability and reliability. The used DTI parameters were fractional anisotropy (FA), the apparent diffusion coefficient (ADC), and axial (AD) and radial (RD) diffusivity.Results: The average ICC of the intra-observer was found to be 0.9 (excellent). The single ICC results were excellent (> 0.8) or adequate (> 0.69) in eight out of the nine regions in terms of FA and ADC. The most reliable results were found in the frontobasal regions. In terms of the regional mean values, significant differences between age groups were found in the frontobasal regions. Specifically, the FA and AD values were significantly higher and the RD values lower in the youngest age group (18-30 years) compared to the other age groups.Conclusions: The quantitative freehand ROI method can be considered highly reliable for the average ICC and mostly adequate for the single ICC. The freehand method is suitable for research work with a well-experienced observer. Measurements should be performed at least twice in the same region to ensure that the results are sufficiently reliable. In our study, reliability was undermined by artifacts in some regions such as the cerebral peduncle, corona radiata and centrum semiovale. From a clinical point of view, the results are most reliable in adults under the age of 30, when age-related changes in brain white matter have not yet occurred.

Muscle sodium content in patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

“…All data were processed and analyzed in Horos by one person. Previous analyses of inter-and intra-operator variability in ROI-based measurements, however, revealed no significant differences between measurements [17,37,42]. Fig.…”

Comparison of region-of-interest delineation methods for diffusion tensor imaging in patients with cervical spondylotic radiculopathy

“…Currently, there are no published studies on ROI delineation methods in nerve root measurement. Wu et al [28] and Wang et al [29] used the multi-point averaging method for the evaluation of the spinal cord and the grading of cervical spondylotic myelopathy, and Zhu et al [25] and Hakulinen et al [26] used the freehand method for the evaluation of cervical spinal cord trauma and brain matter, respectively. These four studies did not examine specifically the nerve roots, and they did not compare different delineation methods.…”

“…Four delineation methods were used: 1) freehand method (Fig. 2A): manually tracing the ROI along the nerve root contour to avoid cerebrospinal fluid interference [25,26]; 2) maximum roundness (Fig. 2B): the round ROI was drawn as large as possible, tangential to the edge of the nerve root, covering the maximum nerve root area and not exceeding the edge [27]; 3) quadrilateral method (Fig.…”

High-frequency longitudinal white matter diffusion- & myelin-based MRI database: reliability and variability

“…To date, consistency of MRI-based WM measurements has been evaluated through numerous studies, especially for the DWI technique (Boekel et al, 2017; Grech-Sollars et al, 2015; Hakulinen et al, 2021; Magnotta et al, 2012; Teipel et al, 2011; Thieleking et al, 2021; Veenith et al, 2013). These studies reported moderate to high reliability in the WM using Intraclass correlation coefficient (ICC) or Pearson’s correlation ranging from 0.5 to >0.8 as well as within- and between-subject coefficients of variation (CV) ranging from 1 to 8% and 1 to 15% respectively.…”

“…These studies reported moderate to high reliability in the WM using Intraclass correlation coefficient (ICC) or Pearson’s correlation ranging from 0.5 to >0.8 as well as within- and between-subject coefficients of variation (CV) ranging from 1 to 8% and 1 to 15% respectively. Among DTI-derived measures, Fractional anisotropy (FA) and Mean Diffusivity (MD) generally show the highest reliability across different WM regions (Acheson et al, 2017; Hakulinen et al, 2021; Luque Laguna et al, 2020; Palacios et al, 2017; Shahim et al, 2017; Thieleking et al, 2021; Zhou et al, 2018). For NODDI-derived measures, studies reported similar (intracellular volume fraction, ICvf) or higher (orientation dispersion, OD) reliability compared to DTI measures, while isotropic volume fraction (ISOvf) showed the poorest reliability (ICC<0.6) (Andica et al, 2020; Chung et al, 2016; Granberg et al, 2017; Lucignani et al, 2021; Tariq, 2013).…”