LTRC Protocol CT Scan
The LTRC CT Scan is the preferred CT scan protocol to be collected for phenotyping the participant in the LTRC. The LTRC CT Scan is designed specifically to allow quantitative analysis of the lung as part of the LTRC project, and requires specific acquisition and reconstruction parameters that enable data to be as comparable as possible between the different participants. A subset of the CT scanners available at the clinical centers will be certified for use in obtaining this specific LTRC CT scan trial through an ongoing QA assessment and Protocol validation process. The precise parameters used for obtaining this LTRC CT dataset will be optimized for each specific CT scanner at a clinical center. Specifically, the full LTRC CT Scan Protocol will consist of helically acquired datasets on a multidetector CT scanner (with no less than 16 detectors) as well as scout/localization images as needed. Thin-slice images (1.0 mm or less) will be obtained and reconstructed at 50% overlap in both a high-resolution kernel (with specific accommodation for this kernel's density accuracy) and a kernel with lower noise and spatial frequency. These scans will be obtained in the supine position at full inspiration, supine and suspended full expiration and prone full inspiration. Scans will be optimized to allow for single breath acquisition in less than 10 seconds. Radiation dose will be adjusted for the participant's size. The ALARA (as low as reasonably allowable) principle will be utilized in these studies with accommodation for the adequate signal/noise ratio to realize the experimental quantitative analysis goals of the LTRC. The effective dose for the inspiratory phase LTRC CT Scan will be approximately 3-5 millisieverts (mSv), and a lower dose expiratory phase and prone series will each be approximately 2-3 mSv.
The images obtained from these scans will be sent to the Radiology Core Laboratory for analysis and storage as described below. Several scan protocols, based on different CT scanner brands and models, with appropriate weight-based dose adjustments and specific breathing instructions for participants and technologist information sheets are included in the LTRC Manual of Operations.