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Updated: Jul 7, 2026
Magnetically-Assisted Remote Controlled Microcatheter Tip Deflection under Magnetic Resonance Imaging
Published on: April 4, 2013
Differentiating intrathecal catheter tip granulomas from normal magnetic resonance image distortion caused by
Stephen T Magill1, Paul Wang, Jorge L Eller
1School of Medicine, Oregon Health & Science University, Portland, Oregon 97239, USA.
Objective:
To characterize the normal image distortion produced by metallic intrathecal catheter tips and define features that differentiate them from a catheter tip granuloma.
Methods:
Three Medtronic Inc. (Minneapolis, MN) intrathecal catheter models (M8709, M8711, and M8731) were placed in a water-filled phantom, which was secured with a spinal coil and scanned with a 1.5-T magnetic resonance imaging (MRI) scanner. MRI scans from two patients receiving intrathecal opiate therapy without a granuloma and one patient with a granuloma were analyzed for comparison.
Results:
All three catheter models produced a metallic susceptibility artifact, which distorted the local tissue image. The tip appeared as a round, dark void sandwiched between two bright bands in the sagittal plane. Axial views produced an oval-shaped, dark central void completely surrounded by a bright rim. On MRI scans, catheter tip diameter varied from 2.3 to 6.7 mm and tip length varied from 4.0 to 7.5 mm, which is a 74 to 480% increase over their actual size. The catheter tip appearance in the phantom correlated with the tip appearance in MRI scans from patients with intrathecal catheters. Images from a tip granuloma show a bright rim surrounding the catheter tip in the sagittal plane with or without contrast as well as postcontrast enhancement of the whole granuloma, and the catheter tip appeared greater than 5 mm in diameter and length.
Conclusion:
When evaluating possible granuloma development around an intrathecal catheter tip, it is important to take into account the characteristic metallic susceptibility artifact and increased size of normal metallic catheter tips on MRI scans.
Insights
Metallic intrathecal catheter tips cause image distortion on MRI scans. Understanding these artifacts is key to distinguishing them from granulomas, ensuring accurate patient diagnosis.
Area of Science:
- Radiology
- Neurosurgery
- Medical Imaging
Background:
- Metallic intrathecal catheters are used for pain management.
- Image artifacts can complicate the assessment of catheter tip complications, such as granulomas.
Purpose of the Study:
- To characterize magnetic resonance imaging (MRI) artifacts from metallic intrathecal catheter tips.
- To identify features distinguishing normal catheter tip artifacts from catheter tip granulomas.
Main Methods:
- Three intrathecal catheter models were scanned using a 1.5-T MRI scanner in a phantom study.
- MRI scans from patients with and without catheter tip granulomas were analyzed for comparison.
Main Results:
- Metallic catheter tips produced characteristic susceptibility artifacts, distorting surrounding tissue.
- Artifacts appeared as dark voids with bright rims/bands, with significant size increases (74-480%).
- Granulomas showed distinct postcontrast enhancement and a bright rim in the sagittal plane.
Conclusions:
- Normal metallic catheter tip artifacts on MRI are distinct from granulomas.
- Awareness of artifact characteristics is crucial for accurate diagnosis of catheter tip granulomas.
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