Retrospective respiratory triggering renal perfusion MRI.

Area of Science:

• Medical Imaging
• Renal Physiology
• Magnetic Resonance Imaging

Background:

• Respiratory motion significantly limits the quality of dynamic contrast-enhanced MRI (DCE-MRI) in kidney imaging.
• Motion artifacts can obscure important details in renal perfusion measurements.

Purpose of the Study:

• To introduce and assess a retrospective triggering technique for minimizing respiratory motion effects in renal DCE-MRI.
• To evaluate the impact of this method on the accuracy of renal perfusion parameters.

Main Methods:

• Nine patients underwent renal perfusion measurements using a 2D saturation-recovery TurboFLASH sequence.
• Three distinct triggering regions of interest (ROIs) were manually defined to assess their impact on results.
• Renal function parameters including plasma flow (F(P)), plasma volume (V(P)), and transit times (T(P), T(T)) were calculated.

Main Results:

• The triggered data demonstrated sufficient temporal resolution for accurate blood flow measurement.
• Average renal function parameters were calculated, with low variability across different triggering ROIs (e.g., F(P) variability: 0.81%-9.87%).
• The method effectively reduced oscillations and sharpened parametric maps.

Conclusions:

• Retrospective triggering is a clinically viable method to reduce respiratory motion artifacts in renal DCE-MRI.
• This technique enhances signal curve consistency and improves the clarity of parametric maps.
• While effective, a semi-automatic method for ROI selection is recommended to decrease user dependency.