Novel whole brain segmentation and volume estimation using quantitative MRI

Abstract

• A method for segmenting the brain and estimating tissue volume is presented • This method measures white matter, grey matter, cerebrospinal fluid and remaining tissue • The method calculates tissue fractions in voxel, thus accounting for partial volume • Repeatability was 2.2% for total brain volume with imaging resolution <2.0 mm.

Automated Determination of Brain Parenchymal Fraction in Multiple Sclerosis

“…Voxels containing 2 or more tissue types display values in an area between these positions, enabling estimation of partial volume values. 13 All voxels containing CSF, gray matter, or WM were included in an ICV mask, followed by a region growing algorithm to ensure that the ICV was represented as a continuous volume and thus also including NON. Special care was taken to ensure that the ICV edge lies at a PD of 50%, under the assumption that it is the interface between CSF (with visible PD ϭ 100%) and bone (with visible PD ϭ 0%).…”

“…This is a further development of synthetic MR imaging, where conventional MR images are synthesized based on MR imaging quantification of the longitudinal R1 relaxation rate, the transverse R2 relaxation rate (defined as 1/T1 relaxation time and 1/T2 relaxation time, respectively), and the proton attenuation PD. [10][11][12] Rather than using images, this new technique defines the tissue types of the brain as specific combinations of these 3 parameters and can thereby synthesize tissue maps, 13 similar to the Alfano method. [14][15][16] In this way, the major components of the ICV (gray matter, WM, and CSF) can be defined by physical properties rather than by relative image characteristics.…”

“…This method includes calculation of tissue fractions in each voxel, decreasing errors caused by partial volume effect. 13 This method is relatively fast, with a postprocessing time that makes it feasible for use in the clinical setting.…”

Clinical Feasibility of Synthetic MRI in Multiple Sclerosis: A Diagnostic and Volumetric Validation Study

“…4,5 The quantitative nature of the method and its ability to probe multiple physical properties in a single sequence make it suitable for volumetric analysis. [6][7][8][9][10] Synthetic MR imaging has shown promising initial results for use in MS and patients with an ischemic event. 11,12 The technique is consequently gaining interest as a potentially time-efficient alternative to conventional MR imaging to visualize and quantify brain tissue properties.…”

Automatic brain segmentation using fractional signal modeling of a multiple flip angle, spoiled gradient-recalled echo acquisition

“…Although such segmentation methods do exist, they are still not readily available [7,8]. One way of performing such a data-driven segmentation is to use quantitative T1 mapping, as suggested by Shin et al [7], employing a multi inversion time (multi-TI) inversion recovery (IR) sequence.…”