The Contribution of Common Surgically Implanted Hardware to Functional MR Imaging Artifacts

Area of Science:

• Medical Imaging
• Neuroimaging
• Radiology

Background:

• Blood oxygenation level-dependent (BOLD) MRI is crucial for assessing brain function.
• Metallic implants can cause susceptibility artifacts, compromising BOLD MRI data.
• Assessing the impact of surgical hardware on BOLD MRI is essential for clinical interpretation.

Purpose of the Study:

• To quantify the volume of BOLD MRI artifacts caused by metallic implants.
• To evaluate the impact of these artifacts on the clinical interpretability of functional MRI data.
• To identify specific types of hardware that pose the greatest challenge to BOLD MRI.

Main Methods:

• Retrospective analysis of 343 BOLD MRIs (3T, gradient echo EPI) acquired between 2006-2014.
• Categorization of patients by cerebrovascular disease or functional localization (language/motor).
• Measurement of artifact volume and assessment of interpretability by a neuroradiologist.

Main Results:

• Intracranial hardware produced mean artifact volumes of 4.3 cm³ with no-to-mild interpretability impact.
• Extracranial hardware resulted in larger artifacts (28.4-39.9 cm³), with no-to-moderate impact, except for one case.
• Ventriculoperitoneal shunts generated the largest artifacts (mean 95.7 cm³), causing moderate-to-severe limitations in interpretation.

Conclusions:

• BOLD MRI provides interpretable functional maps for most patients with metallic implants, even with artifacts up to 30-40 cm³.
• Ventriculoperitoneal shunts, especially those with programmable valves, and numerous KLS-Martin maxDrive screws are exceptions.
• Careful consideration of hardware type and location is necessary for accurate BOLD MRI interpretation.