An Introduction To PACS

Disease evaluation by imaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) is an accurate, reproducible, and easily accessible methodology used in pharmaceutical trials. The value of imaging tools in the evaluation of response to chemotherapeutic agents and other disease modifying agents has been noted in the literature.1,2
Imaging tools such as CT, MRI, and positron emission tomography (PET) scans have complemented serological markers like CEA (carcino-embryogenic antigen) and PSA (prostate-specific antigen) in disease-response evaluation following chemotherapy in patients with colon carcinoma and prostate carcinoma. Imaging tools give detailed information regarding extent and spread of the cancer when compared to the biochemical markers during disease response evaluation.1
Response evaluation by biochemical markers can give false positive and often inaccurate assessment of tumor response. Imaging modalities such as CT and MRI are advantageous because subtle and early changes in lesion progression can be documented more accurately.
Imaging core labs coordinate clinical trials workflow using imaging modalities as the follow-up tool. The images are acquired at various sites all over the world and sent to the imaging core lab, which is analogous to a radiology department. The images received from various sites are either hard-copy films or soft-copy images on magneto-optical disks (MODs) and CDs. The image visualization on computer monitors is analogous to image interpretation using picture archiving and communication systems (PACS) in hospital settings.
References
1. Y. Kitagawa, S. Nishizawa, K. Sano, T. Ogasawara et al., "Prospective Comparison of 18F-FDG PET with Conventional Imaging Modalities (MRI, CT, and 67Ga scintigraphy) in Assessment of Combined Intra-arterial Chemotherapy and Radiotherapy for Head and Neck Carcinoma," J Nucl Med, 44 (2) 198–206 (2003).
2. A.R. Padhani and L. Ollivier, "The RECIST (Response Evaluation Criteria in Solid Tumors) Criteria: Implications for Diagnostic Radiologists," Br J Radiol, 74 (887) 983–986 (2001).
3. S.R. Prasad, S. Saini, J.E. Sumner, P.F. Hahn, D. Sahani, G.W. Boland, "Radiological Measurement of Breast Cancer Metastases to Lung and Liver: Comparison Between WHO (Bidimensional) and RECIST (Unidimensional) Guidelines," J Comput Assist Tomogr, 27 (3) 380–384 (2003).
4. V. Trillet-Lenoir, G. Freyer, P. Kaemmerlen et al., "Assessment of Tumour Response to Chemotherapy for Metastatic Colorectal Cancer: Accuracy of the RECIST Criteria," Br J Radiol, 75 (899) 903–908 (2002).
5. M. Li, D. Wilson, M. Wong, A. Xthona, "The Evolution of Display Technologies in PACS Applications," Comput Med Imaging Graph, 27(2–3)175–184 (2003). G. Gamsu and E. Perez, "Picture Archiving and Communication Systems (PACS)," J Thorac Imaging, 18 (3) 165–168 (2003).
6. A.A. Twair, W.C. Torreggiani, S.M. Mahmud, N. Ramesh, B. Hogan, "Significant Savings in Radiologic Report Turnaround Time After Implementation of a Complete Picture Archiving and Communication System (PACS)," J Digit Imaging, 13 (4) 175–177 (2000).