Tartaro A, Larici A R, Antonucci D, Merlino B, Colosimo C, Bonomo L
Istituto di Scienze Radiologiche, Università G. D'Annunzio, Chieti.
Radiol Med. 1998 Jul-Aug;96(1-2):10-7.
Conventional Computed Tomography (CT) with three-dimensional (3D) reconstructions is considered the most complete and accurate imaging modality to diagnose craniosynostosis. However, the introduction of Spiral CT (SCT) opened new possibilities for 3D studies of the skull in pediatric patients with craniosynostosis. The purpose of our study is two fold: first, to optimize the scanning and imaging parameters to obtain diagnostic images in a single spiral scan; second, to assess the diagnostic accuracy of such images in the identification of normal and abnormal cranial vault sutures.
Seventy-eight pediatric patients (age range: 1-35 months; mean: 11.8 months) with craniosynostosis were submitted to SCT of the head. The images were acquired with the following parameters: 3- and 5-mm nominal slice thickness, 5-6 mm/s table feed (pitch 1-2), 165 mAs and 120 kV. Two different algorithms and increases were used for image reconstructions. A first set of images was reconstructed with 2-mm increases and a soft tissue algorithm: these images were used for brain studies and for 3D reconstructions. A second set of slices was reconstructed with 5-mm increases and a bone algorithm to visualize the sutures of the axial plane. The 3D images were processed with the Shaded Surface Display software with threshold values ranging 120-150 HU. All images were acquired with a single spiral scan lasting less than 30 seconds. Two blinded radiologists analyzed the 3D and the planar images independently to evaluate the course and depth of each cranial suture. The sensitivity, specificity and diagnostic accuracy of both 3D and planar SCT images were evaluated. The frequency of artifacts (the Lego effect, boiled egg, pseudoforamina, movement, and chainsaw artifacts) and their influence on the final diagnosis were studied on 3D SCT images.
The diagnostic accuracy rates of 3D SCT images, by suture, were: sagittal 90.7%, metopic 100%, left lamboid 90.9%, right lamboid 93.9%, left coronal 85.7%, right coronal 91.1%. The diagnostic accuracy rates of the axial images, by suture, were: sagittal 90.7%, metopic 95.5%, left lamboid 86.4%, right lamboid 90.9%, left coronal 83.7%, right coronal 91.1%. The interobserver agreement on 3D images was: sagittal 91.1%, metopic 100%, left lamboid 88.9%, right lamboid 91.1%, left coronal 88.9%, right coronal 84.4%. The Lego effect artifact was the most frequent one (82%) and affected image evaluation in 6.3% of cases.
Our results prove that 3D SCT is a very accurate technique for identifying normal and abnormal sutures and presents many advantages over conventional 3D CT in the examination of pediatric patients with craniosynostosis. The quality of 3D SCT images was adequate and the artifacts did not affect the final diagnostic yield significantly.
采用三维（3D）重建的传统计算机断层扫描（CT）被认为是诊断颅缝早闭最完整、准确的成像方式。然而，螺旋CT（SCT）的引入为患有颅缝早闭的儿科患者的颅骨3D研究开辟了新的可能性。我们研究的目的有两个：第一，优化扫描和成像参数，以便在单次螺旋扫描中获得诊断图像；第二，评估此类图像在识别正常和异常颅顶缝方面的诊断准确性。
78例患有颅缝早闭的儿科患者（年龄范围：1 - 35个月；平均：11.8个月）接受了头部SCT检查。图像采集参数如下：标称层厚3毫米和5毫米，床速5 - 6毫米/秒（螺距1 - 2），165毫安秒和120千伏。图像重建使用了两种不同的算法及间隔。第一组图像以2毫米间隔和软组织算法重建：这些图像用于脑部研究和3D重建。第二组切片以5毫米间隔和骨算法重建，以观察轴位平面的缝。3D图像使用阈值范围为120 - 150亨氏单位（HU）的表面阴影显示软件进行处理。所有图像均通过单次螺旋扫描采集，持续时间不到30秒。两名不知情的放射科医生独立分析3D图像和平面图像，以评估每条颅缝的走行和深度。评估了3D和平面SCT图像的敏感性、特异性和诊断准确性。在3D SCT图像上研究了伪影（乐高效应、煮鸡蛋效应、假孔、运动和电锯伪影）的频率及其对最终诊断的影响。
3D SCT图像按缝的诊断准确率分别为：矢状缝90.7%，额缝100%，左侧人字缝90.9%，右侧人字缝93.9%，左侧冠状缝85.7%，右侧冠状缝91.1%。轴位图像按缝的诊断准确率分别为：矢状缝90.7%，额缝95.5%，左侧人字缝86.4%，右侧人字缝90.9%，左侧冠状缝83.7%，右侧冠状缝91.1%。3D图像的观察者间一致性分别为：矢状缝91.1%，额缝100%，左侧人字缝88.9%，右侧人字缝91.1%，左侧冠状缝88.9%，右侧冠状缝84.4%。乐高效应伪影最为常见（82%），在6.3%的病例中影响图像评估。
我们的结果证明，3D SCT是一种用于识别正常和异常缝的非常准确的技术，在检查患有颅缝早闭的儿科患者方面比传统3D CT具有许多优势。3D SCT图像质量良好，伪影对最终诊断结果影响不大。
