Real-time trajectory guide tracking for intraoperative MRI-guided neurosurgery.

Area of Science:

• Neurosurgery
• Medical Imaging
• Robotics

Background:

• Current intraoperative MRI (iMRI) methods for trajectory guidance are iterative, leading to infrequent updates compared to optical methods.
• Existing iMRI techniques require qualitative image interpretation for device alignment, increasing operator workload.
• There is a need for real-time interactive iMRI guidance to improve efficiency and accuracy in neurosurgical procedures.

Purpose of the Study:

• To develop and evaluate a real-time interactive intraoperative MRI (iMRI) method for aiming trajectory guides at intracerebral targets.
• To overcome the limitations of infrequent updates and subjective image interpretation in current iMRI techniques.
• To enhance the precision and efficiency of image-guided neurosurgery.

Main Methods:

• A real-time platform (RTHawk) was used to control MR sequences and data acquisition for continuous updates.
• Trajectory was computed from two points along the guide's axis by correlating radial spokes with the guide's projection.
• The system provided real-time on-screen visual feedback, enabling simultaneous guide manipulation and alignment with the planned trajectory.

Main Results:

• The real-time interactive iMRI method achieved update rates of 5 Hz.
• Phantom experiments demonstrated high accuracy, with cannula tip placement radial error as low as 0.16 mm (mean 0.29 mm) at 48 mm depth.
• Successful in vivo delivery of gene and cell payloads to 14 targets across nine surgeries was achieved with precise guidance.

Conclusions:

• The developed real-time interactive iMRI method provides rapid, accurate guidance for neurosurgical trajectory aiming.
• Objective computation of device alignment eliminated the need for qualitative image interpretation, reducing operator fatigue.
• This advancement offers a more efficient and accurate alternative to existing iMRI and stereotactic methods.