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Updated: Apr 24, 2026
Role of Diffusion MRI Tractography in Endoscopic Endonasal Skull Base Surgery
Published on: July 5, 2021
Spatial distortion due to field inhomogeneity in 3.0 tesla intraoperative MRI
Asim F Choudhri1, Eric M Chin2, Paul Klimo3
1Department of Radiology, University of Tennessee Health Science Center; Memphis, TN, USA - Le Bonheur Neuroscience Institute, Le Bonheur Children's Hospital; Memphis, TN, USA - achoudhri@uthsc.edu.
Abstract:
We describe a 14-year-old boy with a pilocytic astrocytoma of the left caudate head. Preoperative localization MR imaging (MRI) was performed in the operating room, and spatial distortion was noted felt to be related to head positioning relative to the isocenter of the magnetic field. The distortion artifact was subtle enough to be difficult to detect, but large enough to change the location of the lesion potentially leading to a non-diagnostic stereotactic biopsy. Repeat imaging after changing the head position to allow scanning closer to the isocenter of the magnetic field showed decreased distortion, an improvement greater than that using the manufacturer's distortion correction algorithm on the initial images. Intraoperative MRI, and its requisite limitations in positioning, requires vigilance to detect possible distortion that could alter surgical outcomes if not identified and corrected prospectively.
Insights
Intraoperative MRI (magnetic resonance imaging) can have spatial distortion artifacts due to head positioning. Vigilance is needed to detect and correct these subtle distortions for accurate surgical biopsies.
Area of Science:
- Neurosurgery
- Neuroradiology
- Medical Imaging
Background:
- Intraoperative magnetic resonance imaging (iMRI) is crucial for precise neurosurgical procedures.
- Accurate lesion localization is essential for stereotactic biopsy and surgical planning.
- Spatial distortion in iMRI can compromise diagnostic accuracy and surgical outcomes.
Observation:
- A 14-year-old boy presented with a pilocytic astrocytoma in the left caudate head.
- Preoperative iMRI revealed subtle spatial distortion artifacts attributed to patient head positioning.
- The distortion was significant enough to potentially mislocate the lesion for biopsy.
Findings:
- Altering head position to scan closer to the magnetic field's isocenter significantly reduced distortion artifacts.
- The improvement in image quality from repositioning surpassed the manufacturer's distortion correction algorithm.
- This highlights the impact of head positioning on iMRI fidelity.
Implications:
- Intraoperative MRI requires careful attention to patient positioning to mitigate spatial distortion.
- Detecting and correcting these artifacts prospectively is vital for ensuring diagnostic accuracy in stereotactic biopsies.
- Vigilance in iMRI interpretation can prevent potential surgical complications and improve patient outcomes.
