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In vivo MRI visualization of mesh shrinkage using surgical implants loaded with superparamagnetic iron oxides
Nicolas Kuehnert1, Nils A Kraemer, Jens Otto
1Department of Surgery, University Hospital, RWTH Aachen University, 52074, Aachen, Germany. nkuehnert@ukaachen.de
Background:
Prosthetic mesh implants are widely used in hernia surgery. To show long-term mesh-related complications such as shrinkage or adhesions, a precise visualization of meshes and their vicinity in vivo is important. By supplementing mesh fibers with ferro particles, magnetic resonance imaging (MRI) can help to delineate the mesh itself. This study aimed to demonstrate and quantify time-dependent mesh shrinkage in vivo by MRI.
Methods:
Polyvinylidenfluoride (PVDF) meshes with incorporated superparamagnetic iron oxides (SPIOs) were implanted as an abdominal wall replacement in 30 rats. On days 1, 7, 14, or 21, MRI was performed using a gradient echo sequence with repetition time (TR)/echo time (TE) of 50/4.6 and a flip angle of 20°. The length, width, and area of the device were measured on axial, coronal, and sagittal images, and geometric deformations were assessed by surgical explantation.
Results:
In all cases, the meshes were visualized and their area estimated by measuring the length and width of the mesh. The MRI presented a mean area shrinkage in vivo of 13% on day 7, 23% on day 14, and 23% on day 21. Postmortem measurements differed statistically from MRI, with a mean area shrinkage of 23% on day 7, 28% on day 14, and 30% on day 21. Ex vivo measurements of shrinkage showed in vivo measurements to be overestimated approximately 8%. Delineation of the mesh helped to show folding or adhesions close to the intestine.
Conclusion:
Loading of surgical meshes with SPIOs allows their precise visualization during MRI and guarantees an accurate in vivo assessment of their shrinkage. The authors' observation clearly indicates that shrinkage in vivo is remarkably less than that shown by illustrated explantation measurements. The use of MRI with such meshes could be a reliable technique for checking on proper operation of implanted meshes and showing related complications, obviating the need for exploratory open surgical revision.
Insights
Magnetic resonance imaging (MRI) with SPIO-loaded meshes accurately assesses in vivo shrinkage, revealing less shrinkage than explantation measurements. This technique aids in monitoring mesh performance and detecting complications non-invasively.
Area of Science:
- Biomedical Engineering
- Medical Imaging
- Materials Science
Background:
- Prosthetic meshes are crucial for hernia repair but can cause long-term complications like shrinkage and adhesions.
- Accurate in vivo visualization of meshes is essential for monitoring these complications.
- Superparamagnetic iron oxides (SPIOs) incorporated into mesh fibers can enhance MRI visualization.
Purpose of the Study:
- To demonstrate and quantify time-dependent mesh shrinkage in vivo using MRI.
- To evaluate the accuracy of MRI in assessing mesh deformation compared to explantation.
- To explore the utility of MRI for detecting mesh-related complications.
Main Methods:
- Polyvinylidenfluoride (PVDF) meshes with SPIOs were implanted in 30 rats.
- MRI was performed at specific time points (days 1, 7, 14, 21) using a gradient echo sequence.
- Mesh dimensions and area were measured from MRI images; geometric deformations were assessed post-explantation.
Main Results:
- MRI successfully visualized all SPIO-loaded meshes.
- Mean in vivo area shrinkage was 13% (day 7), 23% (day 14), and 23% (day 21).
- Postmortem measurements showed greater shrinkage (23-30%) than MRI, with MRI overestimating shrinkage by ~8%.
Conclusions:
- SPIO loading enables precise MRI visualization and accurate in vivo assessment of mesh shrinkage.
- In vivo shrinkage is significantly less than indicated by explantation measurements.
- MRI with SPIO-loaded meshes is a reliable, non-invasive method for monitoring mesh function and complications.
