Closed-loop asymmetric-tip needle steering under continuous intraoperative MRI guidance.

Area of Science:

• Medical Imaging
• Robotics
• Interventional Medicine

Background:

• Magnetic resonance imaging (MRI) offers superior tissue contrast for image-guided needle interventions.
• Robot-assisted surgery is advancing, but MRI-guided procedures lack continuous needle tracking, limiting accuracy.
• Closed-loop systems are needed to enhance needle tip placement accuracy through real-time trajectory correction.

Purpose of the Study:

• To develop and evaluate a robot-assisted system for flexible needle interventions guided by continuous intraoperative MRI.
• To enable real-time manipulation of needle insertion depth and rotation for precise target localization.

Main Methods:

• An MRI-compatible robot was used to control a flexible needle within the MRI scanner bore.
• Continuous multi-planar MRI acquisition guided the robot in adjusting the needle's path.
• Experiments were conducted on gelatin phantoms to assess targeting accuracy.

Main Results:

• The system successfully guided the flexible needle using live MR imaging.
• An average total targeting error of 2.5±0.47mm was achieved.
• An average in-plane error of 2.09±0.33mm demonstrated high precision.

Conclusions:

• The proposed system facilitates accurate robot-assisted needle placement under continuous MRI guidance.
• Real-time image guidance and robotic control significantly improve needle targeting accuracy.
• This technology holds promise for enhancing the precision of minimally invasive procedures.