Technical Note: Development and validation of an open data format for CT projection data
Technical Note: Development and validation of an open data format for CT projection data
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DOI：
10.1118/1.4935406
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发表时间：
2015-12-01
期刊：
影响因子：
3.8
通讯作者：
McCollough, Cynthia
中科院分区：
文献类型：
--
作者：
Chen, Baiyu;Duan, Xinhui;McCollough, Cynthia
目的：无法访问患者 CT 扫描的投影数据是开发和验证新重建算法的主要限制。为了满足这一关键需求，这项工作开发并验证了一种供应商中立的 CT 投影数据格式，该格式将进一步用于构建供公众访问的患者投影数据库。方法：为 CT 投影数据 (CT-PD) 创建了类似医学数字成像和通信 (DICOM) 的格式，称为 DICOM-CT-PD 格式。该格式将衰减信息存储在 DICOM 图像数据块中，并将重建所需的参数存储在 DICOM 标头中的各种标签下（51 个标签用于存储几何和扫描参数，9 个标签用于存储患者信息）。为了验证新格式的准确性和完整性，从两台临床 CT 扫描仪（Somatom Definition Flash，Siemens Healthcare，福希海姆，德国和 Discovery CT750 HD，GE Healthcare，沃克夏，威斯康星州）获取了 ACR CT 认证体模螺旋扫描的 CT 投影数据。解码后（由西门子的作者、GE 的制造商），投影数据被转换为 DICOM-CT-PD 格式。离线 CT 重建由内部和外部重建研究人员仅使用 DICOM-CT-PD 文件中存储的信息和 DICOM-CT-PD 场定义进行。结果：与商业重建 CT 图像相比，使用 DICOM-CT-PD 格式创建的离线重建图像在 CT 数（骨插入物相差 5 HU，空气插入物相差 -9 HU）、图像噪声（+/- 1 HU）和低对比度方面相似。可检测性（两者均可见 6 毫米棒）。由于重建方法不同，与在扫描仪上重建的图像相比，获得的面内和跨面高对比度空间分辨率略有不同（轴向平面：GE离线，7 lp/cm；GE商业，7 lp/cm；西门子离线，8 lp/cm；西门子商业，7 lp/cm。冠状面：西门子离线，6 lp/cm；西门子商业，8 lp/cm）。结论：供应商中立的扩展DICOM 格式的开发可以实现第三代 CT 扫描仪的 CT 投影数据的开放共享。格式验证表明，DICOM-CT-PD 文件中的几何参数和衰减信息已正确存储，可以使用提供的指令进行检索，并且包含足够的数据用于重建 CT 图像，这些数据与商用扫描仪的图像近似。 (C) 2015 年美国医学物理学家协会。
Purpose: Lack of access to projection data from patient CT scans is a major limitation for development and validation of new reconstruction algorithms. To meet this critical need, this work developed and validated a vendor-neutral format for CT projection data, which will further be employed to build a library of patient projection data for public access.Methods: A digital imaging and communication in medicine (DICOM)-like format was created for CT projection data (CT-PD), named the DICOM-CT-PD format. The format stores attenuation information in the DICOM image data block and stores parameters necessary for reconstruction in the DICOM header under various tags (51 tags to store the geometry and scan parameters and 9 tags to store patient information). To validate the accuracy and completeness of the new format, CT projection data from helical scans of the ACR CT accreditation phantom were acquired from two clinical CT scanners (Somatom Definition Flash, Siemens Healthcare, Forchheim, Germany and Discovery CT750 HD, GE Healthcare, Waukesha, WI). After decoding (by the authors for Siemens, by the manufacturer for GE), the projection data were converted to the DICOM-CT-PD format. Off-line CT reconstructions were performed by internal and external reconstruction researchers using only the information stored in the DICOM-CT-PD files and the DICOM-CT-PD field definitions.Results: Compared with the commercially reconstructed CT images, the off-line reconstructed images created using the DICOM-CT-PD format are similar in terms of CT numbers (differences of 5 HU for the bone insert and -9 HU for the air insert), image noise (+/- 1 HU), and low contrast detectability (6 mm rods visible in both). Because of different reconstruction approaches, slightly different in-plane and cross-plane high contrast spatial resolution were obtained compared to those reconstructed on the scanners (axial plane: GE off-line, 7 lp/cm; GE commercial, 7 lp/cm; Siemens off-line, 8 lp/cm; Siemens commercial, 7 lp/cm. Coronal plane: Siemens off-line, 6 lp/cm; Siemens commercial, 8 lp/cm).Conclusions: A vendor-neutral extended DICOM format has been developed that enables open sharing of CT projection data from third-generation CT scanners. Validation of the format showed that the geometric parameters and attenuation information in the DICOM-CT-PD file were correctly stored, could be retrieved with use of the provided instructions, and contained sufficient data for reconstruction of CT images that approximated those from the commercial scanner. (C) 2015 American Association of Physicists in Medicine.