Ma Grace Mang Yuet, Amirabadi Afsaneh, Inarejos Emilio, Tolend Mirkamal, Stimec Jennifer, Moineddin Rahim, Spiegel Lynn, Doria Andrea S
Department of Radiology, Ohio State University Wexner Medical Center, 410 West 10th Ave, Columbus, OH, 43210, USA.
Department of Diagnostic Imaging, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G1X8, Canada.
Pediatr Rheumatol Online J. 2015 Dec 1;13:53. doi: 10.1186/s12969-015-0051-7.
Currently there is no consensus agreement on the degree of enhancement in normal temporomandibular joints (TMJ) in children, which makes it difficult for clinicians to distinguish between the presence/absence of mild synovitis. Quantitative measurements of synovial and condylar enhancement may be useful additions to current qualitative methods on early MRI diagnosis and follow up of TMJ involvement in JIA. The purpose of the study is to establish thresholds/tendencies for quantitative measures that enable distinction between mild TMJ involvement and normal TMJ appearance based on the degree of synovial and bone marrow enhancement in JIA patients.
TMJ MRI examinations in 67 children with JIA and in 24 non-rheumatologic children who underwent MRI for neurologic/orbit indications were retrospectively assessed. As a priori determined TMJs of JIA patients were categorized into three groups by experienced staff radiologists based on the degree of synovial and condylar enhancement: no active disease (rheumatologic control), mild and moderate/severe findings. The signal intensity (SI) of the synovial tissue around each condyle and of the bone marrow was measured to calculate the enhancement ratio (ER) and relative SI change. The ER was calculated using signal to noise ratios, while relative SI change was calculated using signal intensities alone. Quantitative measurements of synovial and condylar enhancement of TMJs with mild or moderate/severe findings were compared with the rheumatologic and non-rheumatologic controls.
Mean ER values were significantly different between the TMJs without active disease and those with mild and moderate/severe synovial enhancement, with highest values in the moderate/severe group (P < 0.0001). Similar findings were seen for condylar enhancement with P < 0.005. Relative SI change was unable to differentiate TMJs with mild synovitis from the two controls (P > 0.10). 27/60 (45%) TMJs without active disease had osteochondral changes. 8/40 (20%) TMJs in the mild group did not demonstrate any synovial thickening.
Quantitative signal to noise ratios of TMJ synovial and condylar enhancement generate thresholds/tendencies, which offer additional information to differentiate mild synovitis from normal TMJs in JIA patients. Osteochondral changes and synovial thickening may not be reliable indicators of active TMJ involvement and should be differentiated from synovial enhancement.
目前对于儿童正常颞下颌关节（TMJ）强化程度尚无共识，这使得临床医生难以区分是否存在轻度滑膜炎。滑膜和髁突强化的定量测量可能是对目前定性方法的有益补充，有助于幼年特发性关节炎（JIA）患者TMJ受累情况的早期MRI诊断及随访。本研究的目的是基于JIA患者滑膜和骨髓强化程度，建立能够区分轻度TMJ受累与正常TMJ表现的定量测量阈值/趋势。
回顾性评估67例JIA患儿及24例因神经/眼眶指征接受MRI检查的非风湿性患儿的TMJ MRI检查结果。由经验丰富的放射科工作人员根据滑膜和髁突强化程度，将JIA患者预先确定的TMJ分为三组：无活动性疾病（风湿性对照）、轻度及中度/重度表现。测量每个髁突周围滑膜组织及骨髓的信号强度（SI），计算强化率（ER）及相对SI变化。ER使用信噪比计算，而相对SI变化仅使用信号强度计算。将轻度或中度/重度表现的TMJ滑膜和髁突强化的定量测量结果与风湿性及非风湿性对照进行比较。
无活动性疾病的TMJ与轻度及中度/重度滑膜强化的TMJ之间，平均ER值存在显著差异，中度/重度组最高（P＜0.0001）。髁突强化也有类似发现，P＜0.005。相对SI变化无法区分轻度滑膜炎的TMJ与两个对照组（P＞0.10）。60个无活动性疾病的TMJ中有27个（45%）存在骨软骨改变。轻度组40个TMJ中有8个（20%）未显示任何滑膜增厚。
TMJ滑膜和髁突强化的定量信噪比产生阈值/趋势，为区分JIA患者轻度滑膜炎与正常TMJ提供了额外信息。骨软骨改变和滑膜增厚可能不是TMJ活动性受累的可靠指标，应与滑膜强化相区分。
