Division of Nuclear Medicine, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02115, USA.
Eur J Nucl Med Mol Imaging. 2010 May;37(5):1002-10. doi: 10.1007/s00259-009-1337-0. Epub 2009 Dec 22.
Planar scintigraphy using (99m)Tc-labeled methylene diphosphonate ((99m)Tc-MDP) has been established as a method for evaluating mandibular growth and asymmetry. However, (99m)Tc-MDP single photon emission computed tomography (SPECT) provides improved image contrast and quantitative capability potentially allowing the clinician to make a more accurate assessment of the stage of activity of normal and asymmetric mandibular growth. The purpose of this study was to utilize (99m)Tc-MDP SPECT in normal subjects to develop a standardized approach to imaging the mandible that could subsequently be used to evaluate patients with potential for mandibular growth abnormalities.
Thirty-two patients (22 females, 10 males, 8-25 years of age, mean of 14 years) having (99m)Tc-MDP bone scans (7.4 MBq/kg, maximum of 518 MBq) for indications not involving the head were asked to have an additional SPECT that included the mandibular condyles. Internal (clivus) and external (source of known activity included within the field of view) standards were both investigated. Two- and three-dimensional (2-D and 3-D) regions of interest (ROI) were drawn over each condyle and the clivus in a single slice containing the maximum pixel value within the structure. A 3-D ROI was also drawn about the external standard. Maximum and average pixel values within the 2-D and 3-D ROIs were recorded.
Correlation analysis indicated that essentially the same information was obtained whether the maximum or average pixel value within a 2-D or 3-D ROI was used. The right to left ratio provided a parameter that can be used to assess the magnitude of mandibular metabolic asymmetry. Use of an external standard provides the potential for quantifying condylar uptake for assessment of the activity of mandibular growth. Normal ranges for different age groups were determined for condylar uptake using both internal and external standards.
(99m)Tc-MDP SPECT provides a quantitative method for assessing mandibular condylar uptake as a reflection of the activity of mandibular growth. The maximum pixel value of a 2-D ROI using external standardization and the right to left ratio of the condylar uptake provide the potential for quantitative evaluation of patients with mandibular asymmetry. These parameters will be further evaluated in an upcoming clinical investigation.
使用（99m）Tc 标记的亚甲基二膦酸盐（（99m）Tc-MDP）进行平面闪烁显像已被确立为评估下颌生长和不对称的方法。然而，（99m）Tc-MDP 单光子发射计算机断层扫描（SPECT）提供了改进的图像对比度和定量能力，有可能使临床医生更准确地评估正常和不对称下颌生长的活动阶段。本研究的目的是利用（99m）Tc-MDP SPECT 在正常受试者中开发一种标准化的下颌成像方法，随后可用于评估有下颌生长异常潜力的患者。
32 名患者（22 名女性，10 名男性，8-25 岁，平均 14 岁）因不涉及头部的原因进行了（99m）Tc-MDP 骨扫描（7.4 MBq/kg，最大 518 MBq），要求他们进行额外的 SPECT 检查，包括下颌骨髁。内部（枢椎）和外部（视野内已知活动源）标准均进行了研究。在包含结构内最大像素值的单个切片上，在每个髁突和枢椎上绘制二维（2-D）和三维（3-D）感兴趣区（ROI）。还在外部标准周围绘制了 3-D ROI。记录 2-D 和 3-D ROI 内的最大和平均像素值。
相关分析表明，无论使用 2-D 或 3-D ROI 内的最大或平均像素值，都可以获得基本相同的信息。左右比值提供了一个可用于评估下颌代谢不对称程度的参数。使用外部标准为定量评估下颌生长活动提供了评估髁突摄取的潜力。使用内部和外部标准确定了不同年龄组的髁突摄取正常范围。
（99m）Tc-MDP SPECT 提供了一种定量评估下颌骨髁突摄取的方法，作为下颌生长活动的反映。使用外部标准化的 2-D ROI 的最大像素值和髁突摄取的左右比值为评估下颌不对称患者提供了定量评估的潜力。这些参数将在下一个临床研究中进一步评估。
