Common use of CT Image analysis Clause in Contracts

CT Image analysis. The Hermes Gold ™ image analysis software provides automatic or manual transfer from Digital Imaging and Communications in Medicine (DICOM) supported CT systems and NM Gamma Cameras such as the Philips Precedence SPECT/CT camera, for local storage or automatic forwarding to other systems such as the picture archiving and communication system (PACS). The scan image was first located on the Hermes Gold browser from the scan storage archives for Guy’s Hospital using the subject study number. For subjects that had repeat scans, images were labelled as scan 1 and scan 2 to enable the reader to distinguish between the first and second scan. The image was opened in a ‘hybrid viewer’ mode enabling the viewer to scroll through each of the transaxial slices and identify anatomical regions of interest. The image slice numbers were obtained and each of the anatomical regions was recorded on an ‘anatomical region data sheet’ that had been developed for this study. Each 3mm scan slice was analysed individually and calcified deposits were defined as any area greater that 1mm2 with an attenuation coefficient of ≥ 130 Hounsfield units (HU). Calcification within an ROI was automatically selected by a thresholding function. For this study an attenuation threshold of 130 Hounsfield Units (HU) had been set, in keeping with other studies. Calcified deposits were labelled to emphasise vascular sites using anatomical location and number; for example a calcified deposit located in the AA was labelled as AAORTA Dep 1.This process was repeated for each transaxial slice and provided a volume measurement of calcification for all contiguous slices. Once image analysis was complete, the data file with information pertaining to the amount of calcification identified was then anonymised and exported for statistical analysis.