An open-source software tool for the generation of relaxation time maps in magnetic resonance imaging

Abstract

BackgroundIn magnetic resonance (MR) imaging, T1, T2 and T2* relaxation times represent characteristic tissue properties that can be quantified with the help of specific imaging strategies. While there are basic software tools for specific pulse sequences, until now there is no universal software program available to automate pixel-wise mapping of relaxation times from various types of images or MR systems. Such a software program would allow researchers to test and compare new imaging strategies and thus would significantly facilitate research in the area of quantitative tissue characterization.ResultsAfter defining requirements for a universal MR mapping tool, a software program named MRmap was created using a high-level graphics language. Additional features include a manual registration tool for source images with motion artifacts and a tabular DICOM viewer to examine pulse sequence parameters. MRmap was successfully tested on three different computer platforms with image data from three different MR system manufacturers and five different sorts of pulse sequences: multi-image inversion recovery T1; Look-Locker/TOMROP T1; modified Look-Locker (MOLLI) T1; single-echo T2/T2*; and multi-echo T2/T2*. Computing times varied between 2 and 113 seconds. Estimates of relaxation times compared favorably to those obtained from non-automated curve fitting. Completed maps were exported in DICOM format and could be read in standard software packages used for analysis of clinical and research MR data.ConclusionsMRmap is a flexible cross-platform research tool that enables accurate mapping of relaxation times from various pulse sequences. The software allows researchers to optimize quantitative MR strategies in a manufacturer-independent fashion. The program and its source code were made available as open-source software on the internet.

Native T1 Relaxation Time and Extracellular Volume Fraction as Accurate Markers of Diffuse Myocardial Fibrosis in Heart Valve Disease – Comparison With Targeted Left Ventricular Myocardial Biopsy –

“…The analysis of the T1 relaxation time was performed using the V1.4, MRmap software (https:// sourceforge.net/projects/mrmap) with manual registration of source images and T1 Look-Locker correction. 23 In brief, on parametric maps the ROI was drawn manually on the midwall of the basal interventricular segment matching the region of subsequent perioperative biopsy (Figure 1). Great care was exercised to exclude epicardial structures and blood from the contours.…”

Heart and liver T2* assessment for iron overload using different software programs

“…Therefore, finding similar values with the other two approaches used in comparison to that standard seemed encouraging. Another limitation is that we restricted our comparisons to only three solutions while other tools like MRmap [19] and Hippo-MIOT IFC-CNR [20] are also available and might provide similar findings. We also could have used free spreadsheet software to verify the data as we did with the commercial software Excel.…”

Absolute quantification of perfusion by dynamic susceptibility contrast MRI using Bookend and VASO steady-state CBV calibration: a comparison with pseudo-continuous ASL

“…Images from the 3D Look-Locker sequence were processed by MRmap [23] for calculation of T1 maps, and CBV Bookend was subsequently calculated using Eqs. 3 and 4 by first calculating the mean value of T1 pre and T1 post in the ROIs used for estimation of calibration factors (further described below).…”