Introduction
Materials and methods
Search strategy, information sources, and eligibility criteria
Focused question (PICO) | Does preoperative MRI provide accurate and feasible diagnostic information in healthy volunteers and patients undergoing MTM surgery? | |
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Search strategy | Population | Human studies (patients and/or healthy subjects), aged older than 12 years undergoing MRI prior to MTM surgery #1—((third molar extraction [MeSH]) OR (inferior alveolar nerve [MeSH]) OR (lingual nerve [MeSH]) OR (mandibular nerve [MeSH]) OR (trigeminal nerve [MeSH])) |
Intervention | Magnetic resonance imaging #2—((magnetic resonance imaging [MeSH]) OR (MRI) OR (nuclear magnetic resonance imaging [MeSH]) OR (NMR) OR (diffusion tensor imaging [MeSH]) OR (DTI) OR (ultra-short echo-time [MeSH]) OR (UTE) OR (maxillofacial imaging)) #3—((visualization) OR (neurography)) | |
Comparison | Conventional preoperative radiological assessment #4—((computed tomography [MeSH]) OR (cone-beam computed tomography [MeSH]) #5—(panoramic radiography [MeSH]) | |
Outcome | Feasibility and accuracy of preoperative radiological assessment of MTM region using MRI #6—((accuracy) OR (feasibility) OR (signal-to-noise-ratio [MeSH])) | |
Search combination(s) | (#1) AND (#2 or #3) OR (#6) |
Data extraction and collection
Quality assessment in individual studies
Results
Study selection
Study characteristics
Study number | Author, year, country | Study | Sample size | Age | Study objectives | MRI sequences | Field strengths | Type of MRI coil | Acquisition time | MR device | Outcome (feasibility/accuracy) |
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1 | Miloro et al. 1997, USA | Assessment of the lingual nerve in the third molar region using magnetic resonance imaging | 10 | 21–35 years | Determination of the precise in situ location of the lingual nerve in the third molar region by high-resolution MRI | Phase encode time reduction acquisition (PETRA) sequence | 1.5 T | surface coil | 9:17 min | Signa MRI Unit, General Electric Medical Systems, Milwaukee, Wisconsin, USA | Precise lingual nerve visualization in the third molar region using the PETRA sequence. Assessment of the nerve diameter, the different shapes of the nerve, and the mean vertical and horizontal distances to the lingual crest and the lingual plate of the mandible |
2 | Ferretti et al. 2009, Italy | Dental magnetic resonance imaging: study of impacted mandibular third molars | 29 | 15–28 years | Evaluation of the relationship between the mandibular canal and impacted mandibular third molars using MRI | T1 weighted (short repetition time (TR)/short echo time (TE)) with spin echo (SE) technique or proton-density (PD)-weighted (long TR/short TE) with turbo spin echo (TSE) technique | 1.0 T | radiofrequency head coil | N/A | Magnetom Expert; Siemens Medical Systems, Erlangen, Germany | MRI provided a good depiction of anatomical details of the mandibular canal and its relationship to the MTMs |
3 | Chau et al. 2012, Hong Kong | Comparison between the use of magnetic resonance imaging and cone-beam computed tomography for mandibular nerve identification | 11 | N/A | Evaluation of the reliability of the radiographic assessment of the mandibular nerve in MRI or the mandibular canal in CBCT prior to mandibular third molar extraction | T1 weighted Volumetric Interpolated Breath-hold Examination (VIBE) sequence with fat suppression | 3.0 T | 12-channel birdcage head and neck coil | 4 min | Magnetom Trio Tim syngo, Siemens Medical Solutions, Erlangen, Germany | MRI provided better results in identifying the inferior alveolar nerve/canal and can be used to identify the mandibular nerve in cases that are not accurately visualized on CBCT |
4 | Kirnbauer et al. 2018, Austria | Assessment of impacted and partially impacted lower third molars with panoramic radiography compared to magnetic resonance imaging—a proof of principle study | 28 | 13–24 years | Comparison of panoramic radiography and MRI in preoperative radiological assessment considering the positional relationship of impacted and partially impacted mandibular thirds | 3D turbo spin echo (TSE) sequence and 3D constructive interference in steady-state (CISS) sequence | 3.0 T | 8-channel receive-only CPC coil | 20:31 min | Magnetom Trio, a TIM System, Siemens AG, Erlangen, Germany | MRI provided the same information compared with panoramic radiography, with the added advantage of providing three-dimensional information generated without radiation |
5 | Kang et al. 2018, China | Investigation of Zero TE MR in preoperative planning in dentistry | 22 | 26–65 years | Comparison of preoperative assessment of the positional relationship between the mandibular third molar and the mandibular canal in mandibular third molar surgery using CBCT and zero echo-time MRI | Ultrashort and zero echo-time (ZTE) MRI | 3.0 T | 8-channel head neck coil | 3:30 min | MR Discovery 750 W, GE Healthcare, Milwaukee, Wisconsin, USA | ZTE MRI demonstrated the delineation of the teeth and mandible and provided superior visualization of the mandibular canal compared to CBCT Identical results were obtained in the assessment of the spatial relationship between the mandibular third molar and the mandibular canal |
6 | Burian et al. 2020, Germany | MRI of the inferior alveolar nerve and lingual nerve—anatomical variation and morphometric benchmark values of nerve diameters in healthy subjects | 30 | 21–32 years | Imaging of the inferior alveolar nerve and lingual nerve in the mandibular third molar region using black bone MRI sequences | 3D Short tau inversion recovery (STIR), 3D Double-echo steady-state (DESS), and 3D T1 fast field echo (FFE) | 3.0 T | 16-channel Head and Neck Spine Coil | s 5:31 min | Ingenia Elition, Philips Healthcare, Best, the Netherlands | Possibility of accurate visualization of the inferior alveolar nerve and the lingual nerve in the mandibular third molar region. STIR provided the best signal-to-noise ratio. Accurate discrimination of the tissue composition of the mandibular neurovascular bundle was achieved |
7 | Beck et al. 2021, Austria | Is MRI a viable alternative to CT/CBCT to identify the course of the inferior alveolar nerve in relation to the roots of the third molars? | 53 | N/A | Assessment of the spatial relationship between the inferior alveolar and the mandibular third molar using MRI or CT/CBCT images | PD T2 TSE fat saturation (FS) axial, PD TSE FS coronal | 3.0 T | 64 channel head-and-neck coil | 10:44 min | Magnetom Skyra, Siemens Healthcare, Erlangen, Germany | Good inter- and intra-rater agreement in assessing the spatial relationship between IAN and MTM. Additionally, MRI offered advantages in identifying of accessory IAN in comparison to CT/CBCT |
8 | Al-Haj Husain et al. 2021, Switzerland | Mandibular third molar surgery: intraosseous localization of the inferior alveolar nerve using 3D double-echo steady-state MRI (3D-DESS) | 19 | 18–63 years | Evaluation of the intraosseous position of the inferior alveolar nerve within the mandibular canal’s osseous boundaries prior to third molar extraction treatment using preoperative cone-beam computed tomography and magnetic resonance imaging. Assessment of a conversion factor between both imaging modalities | 3D-DESS with water excitation sequence | 3.0 T | 64 channel head-and-neck coil | 12:24 min | Skyra (release VE11c), Siemens Healthi- neers, Erlangen, Germany | Accurate simultaneous visualization of the nerve tissues within osseous boundaries. A conversion factor from IAC in CBCT and MRI to IAN in MRI was determined |
9 | Al-Haj Husain et al. 2021, Switzerland | Preoperative visualization of the lingual nerve by 3D double-echo steady-state MRI in surgical third molar extraction treatment | 19 | 18–63 years | Evaluation of the focal and continuous anatomy of the lingual nerve in the surgically relevant region before mandibular third molar surgery | 3D-DESS with water excitation sequence | 3.0 T | 64 channel head-and-neck coil | 12:24 min | Skyra (release VE11c), Siemens Healthi- neers, Erlangen, Germany | Preoperative clarification of the focal and continuous anatomy of the lingual nerve in the third molar region with high reliability |
10 | Valdec et al. 2021, Switzerland | Comparison of Preoperative Cone-Beam Computed Tomography and 3D-Double Echo Steady-State MRI in Third Molar Surgery | 19 | 18–63 years | Evaluation of the reliability of assessing the positional relationship between the inferior alveolar nerve and the mandibular third molar using CBCT, MRI, and CBCT/MRI image fusion | 3D-DESS with water excitation sequence | 3.0 T | 64 channel head-and-neck coil | 12:24 min | Skyra (release VE11c), Siemens Healthi- neers, Erlangen, Germany | Moderate intra- and inter-rater agreement for the positional relationship was observed, independent of the reader’s experience. MRI provided superior diagnostic benefit regarding early detection of inflammation |
Quality assessment in individual studies
Checklist | Miloro et al. [42] | Ferretti et al. [55] | Chau et al. [43] | Kirnbauer et al. [45] | Kang et al. [56] | Burian et al. [30] | Beck et al. [44] | Al-Haj Husain et al. [31] | Al-Haj Husain et al. [28] | Valdec et al. [26] |
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Objectives: clearly formatted | + | + | + | + | + | + | + | + | + | + |
Study design: described in detail | + | + | + | + | + | + | + | + | + | + |
Settings: described in terms of location; and relevant dates | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + |
Participants:eligibility criteria; and methods of selection described | + ; + | + ; + | −; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + |
Bias: any efforts to address potential sources of bias described | + | − | + | + | + | + | + | + | + | + |
Sample size: explanation of derivation; adequate | −; + | −; + | −; + | −; + | −; + | −; + | + ; + | −; + | −; + | + ; + |
Statistical Methods: described; appropriate for data | −; + | −; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + |
Participants: described | + | + | + | + | + | + | + | + | + | + |
Outcome data: number of outcome events reported | + | + | + | + | + | + | + | + | + | + |
Other analysis: any other analyses conducted reported | − | + | − | − | − | + | + | + | + | + |
Limitations: limitations of the study; and any potential bias discussed | −; + | −; - | −; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + | + ; + |
Interpretation: overall interpretation of results provided | + | + | + | + | + | + | + | + | + | + |
External validity: generalizability of the results discussed | + | − | + | − | − | − | − | − | + | − |
Total out of 18 (percentage) | 14 (78%) | 12 (67%) | 14 (78%) | 15 (83%) | 15 (83%) | 16 (89%) | 17 (94%) | 16 (89%) | 17 (94%) | 17 (94%) |