Magnetic Resonance Imaging of the Ear for Patient-Specific Reconstructive Surgery

Abstract

IntroductionLike a fingerprint, ear shape is a unique personal feature that should be reconstructed with a high fidelity during reconstructive surgery. Ear cartilage tissue engineering (TE) advantageously offers the possibility to use novel 3D manufacturing techniques to reconstruct the ear, thus allowing for a detailed auricular shape. However it also requires detailed patient-specific images of the 3D cartilage structures of the patient’s intact contralateral ear (if available). Therefore the aim of this study was to develop and evaluate an imaging strategy for acquiring patient-specific ear cartilage shape, with sufficient precision and accuracy for use in a clinical setting.Methods and MaterialsMagnetic resonance imaging (MRI) was performed on 14 volunteer and six cadaveric auricles and manually segmented. Reproducibility of cartilage volume (Cg.V), surface (Cg.S) and thickness (Cg.Th) was assessed, to determine whether raters could repeatedly define the same volume of interest. Additionally, six cadaveric auricles were harvested, scanned and segmented using the same procedure, then dissected and scanned using high resolution micro-CT. Correlation between MR and micro-CT measurements was assessed to determine accuracy.ResultsGood inter- and intra-rater reproducibility was observed (precision errors <4% for Cg.S and <9% for Cg.V and Cg.Th). Intraclass correlations were good for Cg.V and Cg.S (>0.82), but low for Cg.Th (<0.23) due to similar average Cg.Th between patients. However Pearson’s coefficients showed that the ability to detect local cartilage shape variations is unaffected. Good correlation between clinical MRI and micro-CT (r>0.95) demonstrated high accuracy.Discussion and ConclusionThis study demonstrated that precision and accuracy of the proposed method was high enough to detect patient-specific variation in ear cartilage geometry. The present study provides a clinical strategy to access the necessary information required for the production of 3D ear scaffolds for TE purposes, including detailed patient-specific shape. Furthermore, the protocol is applicable in daily clinical practice with existing infrastructure.

Bioprinting Complex Cartilaginous Structures with Clinically Compliant Biomaterials

“…Nimeskern et al used MRI to manually segment the cartilaginous structure from surrounding tissues. [ 42 ] Our bioink printing process combined with one of these imaging techniques could provide a more advanced approach to clinical craniofacial cartilage reconstruction where patient-specifi c cartilaginous shape is of interest.…”

MRI and Additive Manufacturing of Nasal Alar Constructs for Patient-specific Reconstruction

“…In order to evaluate the criterion validity of MRI-derived STL models of the alar cartilage all cadaveric STL models were geometrically compared to the μ-CT-derived STL model of the dissected cadaver cartilage (gold standard). A similar method has previously been used to test the precision and accuracy of MRI of ear cartilage 14 . Dissection of the cadaveric alar cartilage demonstrated a complex morphology (Fig.…”

Three‐dimensional reconstruction with serial whole‐mount sections of oral tongue squamous cell carcinoma: A preliminary study

“…Three‐dimensional reconstruction image with CT and MRI had been applied in surgical design . As 3D reconstruction with whole‐mount sample could only be obtained after surgery and with considerable amount of time and human work, to use this method to guide margin design before surgery, in future study, we planned to combine whole‐mount 3D histopathology reconstruction with CT/MRI reconstruction to access the accuracy of CT/MRI 3D reconstruction compared with whole‐mount 3D histopathology reconstruction.…”