Adjustable shunt valve-induced magnetic resonance imaging artifact: a comparative study

Area of Science:

• Neurosurgery
• Radiology
• Medical Device Engineering

Background:

• Adjustable shunt valves are implanted to manage cerebrospinal fluid (CSF) pressure.
• These valves can cause artifacts in Magnetic Resonance Imaging (MRI), potentially affecting diagnostic accuracy.
• Understanding and quantifying these artifacts is crucial for patient management.

Purpose of the Study:

• To compare magnetic resonance imaging (MRI) artifacts induced by two types of implanted adjustable shunt valves: proGAV and Strata II.
• To evaluate artifact prevalence across different MRI pulse sequences, including spin echo (SE), diffusion-weighted (DW), and gradient echo (GRE).

Main Methods:

• MR images from 8 patients with proGAV and 6 patients with Strata II valves were analyzed.
• Artifact areas and volumes were quantified for different pulse sequences and imaging planes.
• Statistical comparisons were made between the two valve types.

Main Results:

• The Strata II valve induced significantly larger artifacts than the proGAV valve in both spin echo (SE) and diffusion-weighted (DW) MRI sequences.
• Artifacts were more pronounced on DW images compared to SE sequences for both valve types.
• Specific quantitative differences were noted: Strata II vs. proGAV in SE (29,761 vs. 2450 mm(3), p=0.003) and DW (100,138 vs. 38,955 mm(3), p=0.025).

Conclusions:

• Adjustable shunt valves, particularly the Strata II, can create significant MRI artifacts that may obscure underlying brain pathology.
• The choice of shunt valve type and implantation site should consider potential MRI artifact generation.
• Further development of less artifact-inducing adjustable shunt valves is warranted, especially for applications involving diffusion-weighted imaging.