Related Experiment Video
Updated: Feb 11, 2026
09:14
Cardiac Magnetic Resonance Imaging at 7 Tesla
Published on: January 6, 2019
12.3K
GRAPPA reconstructed wave-CAIPI MP-RAGE at 7 Tesla
Jolanda M Schwarz1, Eberhard D Pracht1, Daniel Brenner1
1German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
Magnetic Resonance in Medicine
|April 18, 2018
Summary
A new GRAPPA-based reconstruction method for wave-CAIPI MRI enables faster, high-quality brain imaging. This robust technique improves image quality and reduces artifacts without needing precise coil sensitivity maps.
Area of Science:
- Magnetic Resonance Imaging (MRI)
- Medical Imaging Technology
- Neuroimaging
Background:
- Wave-Pointed Auto-calibrating Reconstruction technique (wave-CAIPI) exploits 3D coil sensitivities for improved MRI.
- Standard wave-CAIPI reconstruction can be sensitive to coil estimation accuracy and introduce noise.
- Accelerated MRI acquisition techniques are crucial for reducing scan times and improving patient comfort.
Purpose of the Study:
- To develop and evaluate a GRAPPA-based (Generalized Autocalibrating Partially Parallel Acquisitions) reconstruction algorithm for wave-CAIPI MRI data.
- To assess the robustness and performance of this GRAPPA-based wave-CAIPI method, particularly concerning coil sensitivity estimations.
- To enable ultra-fast, high-quality whole-brain structural imaging using wave-CAIPI at ultra-high field strengths.
Main Methods:
- Developed a noniterative GRAPPA-based reconstruction algorithm using multiple GRAPPA kernels for wave-CAIPI data.
- Implemented a fast 3D magnetization-prepared rapid gradient-echo (MPRAGE) wave-CAIPI sequence for ultra-high field (7T) MRI.
- Evaluated imaging performance by comparing g-factor and root mean square error against Cartesian CAIPIRINHA acquisitions and assessed subcortical segmentation accuracy across five subjects.
Main Results:
- Achieved 16-fold accelerated whole-brain MPRAGE imaging with 1 mm isotropic resolution in 40 seconds at 7T.
- Observed clear image quality improvements compared to Cartesian CAIPIRINHA sampling.
- Demonstrated that 16-fold accelerated wave-CAIPI was comparable to 12-fold accelerated Cartesian CAIPIRINHA, with GRAPPA reconstruction yielding similar quality to SENSitivity Encoding (SENSE).
Conclusions:
- High-quality wave-CAIPI MPRAGE images can be reconstructed using a GRAPPA-based algorithm.
- The noniterative GRAPPA reconstruction is robust, even at high acceleration factors, and does not require coil sensitivity estimations.
- This approach facilitates ultra-fast whole-brain structural imaging by altering the aliasing pattern.
Related Concept Videos
02:12The Wave Nature of Light
61.6K
The nature of light has been a subject of inquiry since antiquity. In the seventeenth century, Isaac Newton performed experiments with lenses and prisms and was able to demonstrate that white light consists of the individual colors of the rainbow combined together. Newton explained his optics findings in terms of a "corpuscular" view of light, in which light was composed of streams of extremely tiny particles traveling at high speeds according to Newton's laws of motion.
61.6K
01:10Wave Parameters
9.4K
The simplest mechanical waves are associated with simple harmonic motion and repeat themselves for several cycles. These simple harmonic waves can be modeled using a combination of sine and cosine functions. Consider a simplified surface water wave that moves across the water's surface. Unlike complex ocean waves, in surface water waves, water moves vertically, oscillating up and down, whereas the disturbance of the wave moves horizontally through the medium. If a seagull is floating on the...
9.4K
01:07Reflection of Waves
4.7K
When a wave travels from one medium to another, it gets reflected at the boundary of the second medium. A common example of this is when a person yells at a distance from a cliff and hears the echo of their voice. The sound waves (longitudinal waves) traveling in the air are reflected from the bounding cliff. Similarly, flipping one end of a string whose other end is tied to a wall causes a pulse (transverse wave) to travel through the string, which gets reflected upon reaching the wall. In...
4.7K
01:20Half wave rectifier
2.5K
A half-wave rectifier is a fundamental circuit in electronics, designed to convert alternating current (AC) voltage into a unidirectional voltage. It utilizes the simplest form of diode rectification, where the circuit comprises a single diode in series with a load resistor and an AC power source.
2.5K
01:22Full wave rectifier
2.8K
A full-wave rectifier is a device that converts alternating current (AC) to direct current (DC) and is more efficient than its half-wave counterpart. It typically includes a center-tapped transformer, two diodes, and a load resistor. The secondary winding of the transformer is divided to provide two equal voltages of opposite polarities, which is the pivotal element of full-wave rectification.
2.8K
01:10Reconstruction of Signal using Interpolation
741
Signal processing techniques are essential for accurately converting continuous signals to digital formats and vice versa. When a continuous signal is sampled with a period T, the resulting sampled signal exhibits replicas of the original spectrum in the frequency domain, spaced at intervals equal to the sampling frequency. To handle this sampled signal, a zero-order hold method can be applied, which creates a piecewise constant signal by retaining each sample's value until the next...
741