Clinical Implications of Pixel Values in PACS ( Picture Archiving and Communications System ) : A comparison with Dual energy X-ray Absorptiometry

Lee, Chong Suh; Shim, Jong Sup; Oh, Won Hwan; Park, Youn Soo; Sung, Ki Sun

Abstract

PACS (Picture Archiving and Communications System) is a computer-based image storage and retrieval system that can store, recall and display medical images rapidly on high resolution workstations. The image acquisition system consists of direct digital interface to computed radiography (CR) system. We reviewed X-rays of 84 patients who had both studies of Dual energy X-ray Absorptiometry (DXA) and AP, lateral views of lumbar vertebrae between January and December of 1995. We tried to verify the clinical implication of pixel values on PACS for DXA by comparing pixel values and bone mineral density (BMD) of the 2nd, 3rd and 4th lumbar vertebrae. They were all female between 44 and 72 years old, average age of 59. Bone mineral density (BMD), represented in DXA of a total of 252 vertebrae were mostly in the range of between 0.228 (22%) and 1.318 (121%). Pixel values of the AP and lateral views of the 2nd, 3rd and 4th vertebrae in the PACS workstation were closely correlated to bone mineral density (p=0.0001). The values of the DXA (bone mineral density and T score) get comparatively lower as the pixel values get smaller. In conclusion, the pixel value on PACS interfaced to CR could be utilized as an easy, speedy and economical tool for screening of osteoporosis.