MRI OF THE INFERIOR ALVEOLAR NERVE AND LINGUAL NERVE--BENCHMARK VALUES AND ANATOMICAL VARIETY IN HEALTHY SUBJECTS

• Published in: Clinical neuroradiology (Munich) Vol. 29; no. S1; p. S114
• Main Authors: Burian, Egon, Probst, Florian, Robl, Teresa, Zimmer, Claus, Ritschl, Lucas, Probst, Monika
• Format: Journal Article
• Language: English
• Published: Springer 01.09.2019
• Subjects: CT imaging; Magnetic resonance imaging; Visualization (Computers)
• ISSN: 1869-1439

Background: Radiation based imaging techniques like panoramic radiography, computed tomography (CT) or cone beam computed tomography (CBCT) are currently the standard for depicting the mandibular canal prior to surgical procedures. However, these modalities are lacking sufficient soft tissue visualization of the inferior alveolar nerve (IAN) and the lingual nerve (LN), which is particularly exposed to injury during wisdom tooth removal. Magnetic resonance imaging (MRI) using dedicated imaging sequences showed promising results in the direct visualization of the IAN and the LN with high spatial resolution and signal-to-noise-ratio (SNR) quantification. The aim of this study was to define standard specifications in MRI which allow for benchmark definition of SNR values in healthy subjects. Methods: 33 healthy volunteers were examined on a 3T scanner. The conducted sequence protocol consisted of a 3D STIR, 3D WATS and a 3D T1 FFE "black bone"-sequence. Results: The study highlights the feasibility of a direct visualization of proximal and peripheral branches of the IAN and proximal LN. STIR and WATS sequences allowed for morphological discrimination of nerval and vascular components and their anatomical localization within the mandible. The STIR sequence showed significantly higher signalto-noise-ratios for IAN as well as for the LN in the proximal and distal part of the corresponding nerves (p < 0.05). Discussion: The data presented in this study reveal, that a direct visualization of the course of the IAN and LN is feasible using high resolution STIR and WATS sequences. Furthermore, the imaging protocol conducted not only allowed for reproducible nerve diameter measurements but also for subsequent calculation of quantitative parameters like aSNR. Conclusion: MRI using a dedicated sequence protocol allows for detection, nerve signal quantification and morphological characterization of the course of the IAN and the LN with its variant forms in healthy subjects.