Scans

Role of the Radiology Core Laboratory

The LTRC Radiology Core Laboratory (RCL) will coordinate the collection of CT scans of lung that may be diagnostic of fibrotic and non-fibrotic lung disease.

The role of the RCL is to:

  • Collect, quantitatively assess, and qualitatively assess CT scans sent to the RCL from the LTRC Clinical Centers
  • Transmit CT scans to the Data Coordinating Center for archival and distribution to qualified researchers
  • Transmit quantitative and qualitative CT scan data to the Coordinating Center

Role of the Data Coordinating Center

The DCC is the repository for all CT scans collected for the LTRC. They are responsible for maintaining records on CT scans sent to them by the RCL. These CT scans will be used in future, to-be-determined studies. The CT scans can be collected from the different sources which are described below.

The following types of CT scans are being collected as part of the LTRC:

Horizontal Tabs

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.

Historical CT Scan

A less desirable alternative to the LTRC CT Scan for participants enrolled in the LTRC that still fulfills the imaging requirements is a CT scan of the chest previously obtained for clinical reasons. These historical exams must have been obtained less than six months from the time of evaluation at the clinical center and must also be in digital DICOM format for transfer to the RCL. Volumetric high-resolution imaging (slice thickness less than 2mm) with a field of view sufficient to visualize the entire lung volume with non-contrast technique is preferred.  The CT portion of a PET/CT, imaging performed with intravenous contrast, image acquisition/reconstruction that is not volumetric (i.e. HRCT with gap) or slice thickness greater than 2mm is not preferred.  Subjects who do not have historical imaging with a preferred technique should be strongly encouraged to obtain the LTRC Protocol CT prior to surgery. Radiographs (chest x-ray) and other imaging modalities (MRI, V/Q scans, Ultrasound) are not acceptable. The participant must consent to use of a clinical scan for research purposes, its storage at the Mayo Clinic, or another repository designated by the NHLBI, and the sharing of results and de-identified image data with future researchers as part of the LTRC data repository. If more than one historical exam is available, the most recent examination with optimal acquisition and reconstruction parameters (non-contrast-enhanced, volumetric, high-resolution CT images with (thickness of 2mm or less) will be sent to the RCL for analysis and storage as described in the sections below. In order of preference, non-contrast exam, volumetric high-resolution technique and age of exam are to be considered.  For example, if a 1 week old enhanced pulmonary embolism protocol CT, a 1 month old PET/CT and a 3 month old non-contrast volumetric high-resolution CT are available, the 3-month old non-contrast high-resolution CT would be preferred). The LTRC Protocol CT acquired prospectively would be preferred to any of the historical exams, if that can be acquired prior to surgery.

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