TY - JOUR T1 - Evaluation of Automatic Measurement of the Intracranial Volume Based on Quantitative MR Imaging JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1951 LP - 1956 DO - 10.3174/ajnr.A3067 VL - 33 IS - 10 AU - K. Ambarki AU - T. Lindqvist AU - A. Wåhlin AU - E. Petterson AU - M.J.B. Warntjes AU - R. Birgander AU - J. Malm AU - A. Eklund Y1 - 2012/11/01 UR - http://www.ajnr.org/content/33/10/1951.abstract N2 - BACKGROUND AND PURPOSE: Brain size is commonly described in relation to ICV, whereby accurate assessment of this quantity is fundamental. Recently, an optimized MR sequence (QRAPMASTER) was developed for simultaneous quantification of T1, T2, and proton density. ICV can be measured automatically within minutes from QRAPMASTER outputs and a dedicated software, SyMRI. Automatic estimations of ICV were evaluated against the manual segmentation. MATERIALS AND METHODS: In 19 healthy subjects, manual segmentation of ICV was performed by 2 neuroradiologists (Obs1, Obs2) by using QBrain software and conventional T2-weighted images. The automatic segmentation from the QRAPMASTER output was performed by using SyMRI. Manual corrections of the automatic segmentation were performed (corrected-automatic) by Obs1 and Obs2, who were blinded from each other. Finally, the repeatability of the automatic method was evaluated in 6 additional healthy subjects, each having 6 repeated QRAPMASTER scans. The time required to measure ICV was recorded. RESULTS: No significant difference was found between reference and automatic (and corrected-automatic) ICV (P > .25). The mean difference between the reference and automatic measurement was −4.84 ± 19.57 mL (or 0.31 ± 1.35%). Mean differences between the reference and the corrected-automatic measurements were −0.47 ± 17.95 mL (−0.01 ± 1.24%) and −1.26 ± 17.68 mL (−0.06 ± 1.22%) for Obs1 and Obs2, respectively. The repeatability errors of the automatic and the corrected-automatic method were <1%. The automatic method required 1 minute 11 seconds (SD = 12 seconds) of processing. Adding manual corrections required another 1 minute 32 seconds (SD = 38 seconds). CONCLUSIONS: Automatic and corrected-automatic quantification of ICV showed good agreement with the reference method. SyMRI software provided a fast and reproducible measure of ICV. CoVcoefficient of variationICVintracranial volumeObs1observer 1Obs 2observer 2PDproton densityQRAPMASTERquantification of relaxation times and proton density by multi-echo acquisition of a saturation-recovery using turbo spin-echo readout ER -