Single shot MR tagging to quantify local tissue deformation during MRI-guided needle interventions: a feasibility...

Area of Science:

• Medical Imaging
• Interventional Radiology
• Biophysics

Background:

• MRI-guided needle interventions risk localization errors due to tissue deformation from needle movement.
• Accurate monitoring of tissue deformation is crucial for compensating and improving procedural accuracy.
• Existing fast MR scans can track needles but not quantify local tissue deformation without landmarks.

Purpose of the Study:

• To demonstrate the feasibility of single shot MR tagging for quantifying tissue deformation during MRI-guided needle interventions.
• To assess the effectiveness of MR tagging in creating artificial landmarks for deformation monitoring.
• To evaluate tag persistence and visibility in phantom and volunteer experiments.

Main Methods:

• Utilized a 1.5 T MR scanner with a single shot MR tagging sequence.
• Employed a 1331 composite pulse for tag pattern creation and balanced steady state free precession for imaging.
• Conducted experiments on phantoms and a volunteer to quantify translations, rotations, and mimic needle interventions.

Main Results:

• The MR tag pattern was clearly visible and accurately quantified local tissue deformation caused by needle movement (up to 5 mm displacements observed).
• Strong correlations were found between actual and measured phantom motions.
• In vivo tag patterns in the prostate remained visible for at least 2 seconds, with optimized parameters extending persistence.

Conclusions:

• Single shot MR tagging is a viable method for quantifying tissue deformation during MRI-guided needle interventions.
• The demonstrated in-vivo tag persistence is sufficient for clinical application in patients.
• This technique offers a solution for accurate localization and compensation of tissue movement in interventional procedures.