Assessing the length of the mandibular ramus and the condylar process: a comparison of OPG, CBCT, CT, MRI, and lateral cephalometric measurements

SummaryBackground/Objectives: To compare different imaging procedures [cone beam computed tomography (CBCT), computed tomography (CT), magnetic resonance imaging (MRI), orthopantomography (OPG), and lateral cephalometry (LC)] for assessing the mandibular height [ramus height (RH)] and condylar process (CondProc) length as they reflect mandibular growth. Materials/Methods: The RH and CondProc of eight cadaver heads (each side separately) were measured using CBCT, CT, MRI, OPG, and LC. They were measured twice by two independent observers parallel to the posterior border of the mandibular ramus. An intraclass correlation coefficient (ICC) was used to assess the inter- and intraobserver reliability. The coefficient of variation was used to elucidate precision. Bland-Altman (BA) plots were used to assess the agreement between the procedures and the intra- and interobserver measurements. Results: All procedures, with the exception of LC, showed good intra- and interobserver agreement (maximum range of agreement: 5.3mm) and excellent reliability (ICC > 0.9). The BA plot analysis for the CondProc and RH showed similar ranges of agreement between MRI, CT, and CBCT (maximum 6.4mm) but higher ranges for OPG and LC. The MRI and OPG values were generally smaller. Conclusions/Implications: All 3D imaging procedures yielded nearly equal results when used to measure the CondProc and RH. MRI is recommended because it avoids ionizing radiation and has higher sensitivity in the detection of inflammation. A 2-year threshold for detecting growth in the follow-up period should be taken into account for all 3D imaging methods. Measuring the RH is recommended for the follow-up of condylar growth because reference values for annual increments are publishe

Magnetic resonance imaging assessment of temporomandibular joint involvement and mandibular growth following corticosteroid injection in juvenile idiopathic arthritis

OBJECTIVE: To assess whether intraarticular corticosteroid injection (CSI) reduces inflammation of the temporomandibular joint (TMJ), prevents growth disturbances of the mandibular condyle, and restores normal growth of the mandibular ramus. METHODS: Retrospective longitudinal magnetic resonance imaging (MRI) evaluation of inflammatory activity, TMJ deformity, and mandibular ramus height in 33 children (23 girls, median age 5.2 yrs) over a median period of 5 years following repetitive CSI to the TMJ. RESULTS: Intraarticular location of CSI led to inflammatory grade improvement in 53% at first MRI followup compared to 20% with extraarticular location (p = 0.005), with more improvement of the mean inflammatory grade after intraarticular CSI (p = 0.001). Rate of osseous deformities of the TMJ deteriorated from 51% at study inclusion to 62% at end of observation period, with progression to severe condylar destruction in 26% of joints including 24% with development of intraarticular calcifications/ossifications. Mean short-term growth rates of the mandibular ramus were negative for intraarticular CSI while positive for extraarticular CSI (p = 0.036). Mean longterm mandibular ramus growth rate (0.7 ± 0.8 mm/yr) after CSI was significantly lower than reported normal mean age- and sex-matched growth rate (1.4 ± 0.1 mm/yr, p < 0.0001). CONCLUSION: Despite improving the inflammatory activity as seen on MRI, repetitive CSI to the TMJ does not reach the treatment goals to prevent progressive osseous deformation and to normalize mandibular ramus growth in children with juvenile idiopathic arthritis

Assessing the length of the mandibular ramus and the condylar process: a comparison of OPG, CBCT, CT, MRI, and lateral cephalometric measurements

Summary Background/Objectives: To compare different imaging procedures [cone beam computed tomography (CBCT), computed tomography (CT), magnetic resonance imaging (MRI), orthopantomography (OPG), and lateral cephalometry (LC)] for assessing the mandibular height [ramus height (RH)] and condylar process (CondProc) length as they reflect mandibular growth. Materials/Methods: The RH and CondProc of eight cadaver heads (each side separately) were measured using CBCT, CT, MRI, OPG, and LC. They were measured twice by two independent observers parallel to the posterior border of the mandibular ramus. An intraclass correlation coefficient (ICC) was used to assess the inter- and intraobserver reliability. The coefficient of variation was used to elucidate precision. Bland-Altman (BA) plots were used to assess the agreement between the procedures and the intra- and interobserver measurements. Results: All procedures, with the exception of LC, showed good intra- and interobserver agreement (maximum range of agreement: 5.3mm) and excellent reliability (ICC > 0.9). The BA plot analysis for the CondProc and RH showed similar ranges of agreement between MRI, CT, and CBCT (maximum 6.4mm) but higher ranges for OPG and LC. The MRI and OPG values were generally smaller. Conclusions/Implications: All 3D imaging procedures yielded nearly equal results when used to measure the CondProc and RH. MRI is recommended because it avoids ionizing radiation and has higher sensitivity in the detection of inflammation. A 2-year threshold for detecting growth in the follow-up period should be taken into account for all 3D imaging methods. Measuring the RH is recommended for the follow-up of condylar growth because reference values for annual increments are published