QUASAR™ MRID3D is a new, patent pending, cost-effective QA system for quantifying geometric distortion in 3D MR images. Analysis is performed on images for MRgRT and diagnostic imaging applications.
Unlike other distortion analysis products, which only sample a few imaging planes, the QUASAR™ MRID3D Geometric Distortion Analysis System analyzes the entire 3D field of view in a single acquisition.
The system uses a novel method based on 3D harmonic analysis of distortion by analyzing the Boundary Distortion Vector Field derived from the location of known control points on the surface of the phantom. 3D Laplace Partial Differential Equations are used to calculate the entire 3D Distortion Vector Field with ROI selector permitting user analysis of smaller custom volumes. The large, hollow, lighter phantom is easy to setup in MRI scanners and comes with quick and easy-to-use image analysis software.
A submission to Medical Physics is available online:
The QUASAR™ MRID3D Geometric Distortion Analysis System results compare favourably to conventional grid phantoms, which have higher inherent susceptibility/sample distortion.
- Patent Pending
- Waterless Phantom
- Isocenter Detection
- Fiducial Markers
- Reference Markers
- Fast Processing
- Feature-rich Graphics
- Built-in 3D DICOM Viewer
- Frequency Plots
- Automated Analysis
- Trend Analysis
- Export Results
- Detailed Reports
- Multi-Use Phantom
- Large Field of View
- Light Weight
- Complete System
- Optional Inserts
- Uses a novel method for quantifying 3D geometric distortion in MRI based on 3D harmonic analysis
- The removable end plate, XYZ cuboid and fiducial markers are delivered pre-filled with mineral oil for best scanning results
- Features an XYZ orientation and scale cuboid containing fiducialcal channels to easily visualize the phantom isocenter
- Contains 1,496 precisely machined 3mm fiducial markers as recommended by NEMA standard MS 12-2010
- Contains 6 precisely machined 5mm reference fiducials to detect image position when distortion is high or correction is off
- Acquire T1 weighted 3D isotropic GRE scans at 3T under 5 minutes or at 1.5T as quick as 10 minutes
- Enables users to easily visualize analysis results and update visually stunning charts, graphics and plots in real-time
- Ability to update statistical analysis in real-time within a selected region of interest (ROI)
- Allows the user to select 2 identical MR scans with opposite polarities to quickly compare and visualize patterns
- Software automatically locates fiducials, compares it against the truth and calculates the geometric distortion for QA analysis
- Track results over time to identify patterns, prevent potential errors and make adjustments to improve patient care
- Capable of exporting the entire 3D Distortion Vector Field (DVF) data into Microsoft Excel (.CSV) format
- Save distortion measurement results in PDF format to share with physicist, MRI technician and radiation therapists
- Designed for multiple QA applications including MRI-guided radiation therapy, MR simulation and diagnostic imaging
- 37cm x 32cm (W x L) phantom enables users to accurately simulate and QA treatment plans for a wide range of patient sizes
- Phantom weighs 21 kg for easy and fast setup compared to similar sized water-based phantoms that weigh 41 kg or more
- Maintenance free phantom comes complete with XYZ cuboid, analysis software and instructions for safe assembly
- Interchangeable inserts are available upon request for additional QA applications such as image quality and dosimetry
INNOVATIVE DESIGN & FUNCTIONALITY
Features an XYZ orientation and scale cuboid containing fiducial channels to enable users to easily visualize the phantom isocenter
Contains 1,496 precisely machined 3mm fiducial markers with 6 contrastive 5mm central reference fiducials for rapid position detection when imaging distortion is high or while geometric correction is turned off
Designed to work with the MRI laser positioning system to ensure that there is no roll, pitch or yaw displacement of the phantom
Integrated Feet and Handles
Comes with built-in 3 point contact feet for quick set-up on uneven surfaces and fixed handles for convenient carrying and easy storage
Pressure/vacuum sealed fill ports to lock-in mineral oil and prevent leaks due to changes in temperature
Integrated mineral oil thermal expansion tubes provide internal pressure relief to ensure geometric stability
The large, lightweight phantom contains 1,502 mineral oil filled control points on the surface of a hollow twin walled closed acrylic cylinder, weighs less than 21 kg for straightforward practical setup, and comes with quick and easy-to-use image analysis software.
The patent pending temperature compensating oil expansion reservoirs maintain geometric dimensional stability of phantom with temperature variation while in service or transit. This eliminates a potential source of measurement error commonly found in large conventional grid phantoms.
The mineral oil is susceptibility matched to acrylic to minimize susceptibility artefact around the control point. The physical dimensions of the phantom are 39.4 cm diameter by 39.1 cm long – with a hollow internal volume of ~25 liters.
A small insert at the center of the phantom includes a 3,4,5 orientation cube to facilitate initial 3 plane MR Image localizing and establish a frame of reference. This central insert can be replaced with task specific objects for image guidance applications.
Figure caption: 3D comparison of Control Point Image locations (yellow) vs Truth Template from CAD data (green) to calculate Boundary Distortion Vector Field (red) from the difference between control point image location and truth. Results are easily visualized in 3D.
Watch the Demonstration Video →
A video demonstration of the QUASAR™ MRID3D software analysis features for quantifying geometric distortion in 3D MR images.
Read the latest Press Release →
Modus QA Updates MRI Geometric Distortion QA Analysis System with faster isocenter detection, improved fiducial markers, convenient alignment crosshairs and additional visualization tools, making the fastest, lightweight, large field of view MRgRT QA Phantom better than ever.
The robust QUASAR™ MRID3D software automatically identifies the location of the control points in acquired images of the phantom under conditions of low or high distortion e.g. with vendor geometric distortion correction turned off. The results are shown graphically in a 3D display and numerically in a spreadsheet.
The software is compatible with Windows 7 or higher operating systems.
Automated processes are used to identify location of Control Points, quantify Geometric Distortion, calculate Distortion Vector Fields and produce Statistical Analysis.
Complex equations and algorithms are put to use to calculate the phantom Boundary Distortion Vector Field, Volumetric 3D DVF and B0 Distortion vs Gradient Distortions.
Enriched analysis tools make it easier to examine the geometric distortion measurements of a single acquisition or compare the distortion among a collection of series.
Sophisticated 3D DICOM Viewer with ROI selector enables users with the ability to update charts and graphs in real-time to user-defined volumes to gain further insights.
Interactive statistical graphics allow users to explore, discover, summarize and visualize quantitative data in the way they see fit to form conclusions and make decisions.
Control how your data is managed by adjusting settings, image viewer properties, graphic resolution display, change plot line colours and configure the database path.
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