Digital panoramic radiography for diagnosis of the temporomandibular joint: CBCT as the gold standard

Three-dimensional imaging modalities have been reported to be more accurate than panoramic radiographs (PR) for the assessment of bone components of the temporomandibular joint (TMJ). No exact prior information is available that demonstrates which specific limitations occur in terms of TMJ diagnosis when using PR for this purpose. This study aimed to assess the clinical validity of digital panoramic radiography (DPR) when diagnosing morphological disorders of the TMJ using cone-beam computed tomography (CBCT) images as the gold standard. A sample composed of TMJ images (N = 848), including 212 DPR and 212 CBCT images obtained from the same patient, was used to assess any morphological changes in the TMJ. Four appraisers diagnosed all of the DPR images, whereas the CBCT images were used to establish the gold standard. The reliability of each appraiser’s response pattern was analyzed using the Kappa test (κ), and diagnostic tests were performed to assess each appraiser’s performance using a significance level setting of 5% (α = 0.05). Reliability of each appraiser’s response pattern compared to the gold standard ranged from a slight-to-moderate agreement (0.18 ≤ κ ≤ 0.45); and among the different appraisers, the response pattern showed a fair agreement (0.22 ≤ κ ≤ 0.39). Diagnostic tests showed a wide range among the different possible morphological changes diagnosed. DPR does not have validity when diagnosing morphological changes in the TMJ; it underestimates the radiological findings with higher prevalence, and thus, it cannot be used effectively as a diagnostic tool for bone components within this region.

已有研究证实，三维成像模态在评估颞下颌关节（temporomandibular joint，TMJ）骨组织成分时，其诊断准确性优于全景X线片（panoramic radiographs，PR）。目前尚无确切前期研究明确，采用全景X线片开展颞下颌关节诊断时存在哪些具体局限。本研究以锥形束计算机断层扫描（cone-beam computed tomography，CBCT）图像作为金标准，旨在评估数字全景X线摄影（digital panoramic radiography，DPR）诊断颞下颌关节形态学异常的临床有效性。本研究纳入共计848张颞下颌关节图像，其中包含来自同一患者的212张数字全景X线摄影图像与212张锥形束计算机断层扫描图像，用于分析颞下颌关节的形态学变化。4名评估者对所有数字全景X线摄影图像进行诊断，锥形束计算机断层扫描图像则用于构建金标准数据集。采用Kappa检验（κ）分析每名评估者诊断结果的一致性可靠性，并设定显著性水平为5%（α=0.05），开展诊断试验以评估每名评估者的诊断性能。各评估者的诊断结果与金标准的一致性处于轻度至中度水平（0.18 ≤ κ ≤ 0.45）；不同评估者之间的诊断结果一致性仅为一般水平（0.22 ≤ κ ≤ 0.39）。诊断试验结果显示，针对不同类型的颞下颌关节形态学异常，各评估者的诊断效能差异显著。数字全景X线摄影无法有效诊断颞下颌关节的形态学变化：其对该区域影像学表现的检出率偏低，因此不能作为该区域骨组织成分的有效诊断工具。