Computed tomography versus magnetic resonance imaging in stereotactic localization

Area of Science:

• Neurosurgery
• Medical Imaging
• Radiology

Background:

• Neurosurgeons often encounter intracranial lesions clearly visible on MRI but poorly defined on CT.
• Concerns exist regarding geometric distortion within MRI images.
• Accurate lesion localization is critical for stereotactic biopsy and radiosurgery.

Purpose of the Study:

• To compare the accuracy and reliability of CT and MRI stereotaxy for intracranial lesions.
• To evaluate the utility of different MRI imaging planes (axial, coronal, sagittal) in stereotactic procedures.
• To determine the correlation between CT and MRI coordinates for neurosurgical targeting.

Main Methods:

• Five patients with diverse intracranial lesions underwent both CT and MRI.
• The Brown-Roberts-Wells stereotactic system was employed for both imaging modalities.
• Key anatomical landmarks and lesion coordinates were recorded in all three MRI planes and compared with CT data.
• Statistical analysis using Pearson correlation coefficients was performed.

Main Results:

• Axial MRI coordinates were found to be more consistently available and retrievable compared to coronal and sagittal planes.
• Lateral targets, like the optic nerve-globe junction, were more challenging to precisely locate on coronal and sagittal MRI.
• The correlation between MRI and CT was strongest for axial MRI, followed by coronal, then sagittal planes.
• Geometric image distortion in MRI is attributed to magnetic field non-linearity and tissue susceptibility.

Conclusions:

• MRI stereotaxy, particularly using axial views, can be effectively integrated with CT for verifying lesion coordinates in neurosurgery.
• This combined approach is especially beneficial for large lesions or those poorly delineated on CT.
• Axial MRI provides the most reliable spatial correlation with CT for stereotactic neurosurgical applications.