Related Experiment Videos
[Pulse triggering for improved diffusion-weighted MR imaging of the abdomen]
1Radiologische Klinik der Universität Bonn. muertz@imsdd.meb.uni-bonn.de
Purpose:
The aim of this work was to reduce the influence of motion on diffusion-weighted MR images of the abdomen by pulse triggering of single-shot sequences.
Methods:
Five healthy volunteers were examined both without and with finger pulse-triggering of a diffusion-weighted single-shot echo planar MR imaging sequence at 1.5 T. Series of diffusion-weighted images were acquired at different phases of the cardiac cycle by varying the time delay between finger pulse and sequence acquisition. The measurements were repeated three times. The diffusion weighted images were analysed by measuring the signal intensities and by determining the ADC values within the spleen, kidney and liver.
Results:
The magnitude of motion artifacts on diffusion weighted images shows a strong dependence on the trigger delay. The optimum trigger delay is found to be between 500 and 600 ms. For these values the abdominal organs appear homogeneous on all diffusion weighted images and the strongest signal intensities are detected. At optimum triggering the accuracy of the apparent diffusion coefficients is up to 10 times better than without triggering. Moreover, the standard deviation of the repeated measurements is smaller than 12% for all volunteers and for all organs. Without triggering the standard deviation is larger by a factor of 4 on average.
Conclusion:
Pulse triggering of single-shot sequences leads to significant reduction of motion related artifacts on diffusion weighted images of the abdomen and provides more accurate and reproducible ADC values.
Insights
Pulse triggering significantly reduces motion artifacts in abdominal diffusion-weighted MRI. This technique improves the accuracy and reproducibility of apparent diffusion coefficient (ADC) values, enhancing diagnostic quality.
Area of Science:
- Medical Imaging
- Radiology
- Biophysics
Context:
- Diffusion-weighted magnetic resonance imaging (DW-MRI) is crucial for abdominal diagnostics.
- Motion artifacts, particularly from cardiac and respiratory cycles, degrade image quality and diagnostic accuracy.
- Single-shot echo planar imaging (EPI) sequences are susceptible to motion due to their rapid acquisition.
Purpose:
- To investigate the efficacy of finger pulse triggering in reducing motion artifacts in abdominal DW-MRI.
- To optimize the trigger delay for single-shot EPI sequences.
- To assess the impact of pulse triggering on apparent diffusion coefficient (ADC) measurements.
Summary:
- A study involving five healthy volunteers utilized finger pulse triggering with a 1.5 T DW-MRI system.
- Diffusion-weighted images were acquired at various cardiac phases, with measurements repeated to evaluate reproducibility.
- Signal intensities and ADC values in the spleen, kidney, and liver were analyzed to quantify artifact reduction and accuracy improvements.
Impact:
- Pulse triggering significantly reduces motion artifacts, leading to more homogeneous abdominal organs on DW-MRI.
- Optimal trigger delays (500-600 ms) enhance signal intensity and improve ADC accuracy by up to tenfold compared to untriggered sequences.
- This method enhances the reproducibility of ADC measurements, with standard deviations below 12%, a fourfold improvement over non-triggered scans.