Reproducibility Analysis of Brain Volumetry Measured from Inter MR Scanner of Multi-Institute

PURPOSE: The aim of this study was to evaluate the variations of brain volumetry between the different MR scanners or the different institutes. MATERIALS AND METHODS: Ten normal subjects were scanned at four different MR scanners, two of them were the same models, to measure inter-MR scanner variations using intraclass correlation coefficient (ICC), coefficient of variation (CV) and percent volume difference (PVD) and to calculate minimal thresholds to detect the significant volumetric changes in gray matter and subcortical regions. RESULTS: Averaged statistical reliability (ICC = 0.837) and volumetric variation (CV = 4.310%) in all segmented regions were observed on overall MR scanners. Comparing the segmented volumes with PVD between two MR scanners, volumetric differences on same models were the lowest (PVD = 3.611%) and volume thresholds were calculated with 7.168%. PVD results and thresholds values on systemically different MR scanners were evaluated with 5.785% and 11.340% respectively. CONCLUSION: Authors conclude that the reliability of brain volumetry is not so high. Calibration studies of MRI system and image processing are essential to reduce the volumetric variability. Additionally, frameworks comprised of database and algorithms with high-speed image processing are also required for the efficient image data management.

A Comparison Study on Human Brain Volume of White Matter, Gray Matter and Hippocampus Depending on Magnetic Resonance Imaging Conditions and Applied Brain Template

PURPOSE: The aim of this study was to examine the volume differences of human brain 3-D MR images obtained by automatic segmentation methods depending on brain templates and image acquisition conditions, respectively. MATERIALS AND METHODS: 3D T1-weighted MR images oriented in coronal and sagittal plane were acquired from eight healthy subjects (29.5+/-5.66 years) using two identical 3T MR scanners at different sites. Caucasian brain template and Korean elderly brain template were applied for the same subject to segment brain structural region. Volumetric differences and variation of gray matter, white matter and hippocampus depending on scan orientations and brain template types were statistically evaluated. RESULTS: Volumetric measurements have some different results for the same subject images depending on scan orientation in identical MR scanners but not significantly. However, all segmented volumes relied upon brain templates were significantly different (p<0.05). Small variation of the volume in gray matter, white matter (coefficient of variation, CV< or =1%) and hippocampus (CV< or =3%) were obtained. Comparing the mean CV in all segmented regions, variation of scan orientation was not significantly different with inter scanner variation but variation relied upon brain templates were significantly different (p<0.001). CONCLUSION: Authors found that brain template regarding the specific properties of the subjects is required to reduce the errors of brain volumetry.