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Quantitative Imaging: Protocol Development and Quality Assurance Issues for Medical Imaging in Clinical Trials. H. Cecil Charles, Ph.D. Director Duke Image Analysis Laboratory Duke University Medical Center. Overview. Quantitative Imaging vs: Clinical Imaging Protocol Development Issues
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Quantitative Imaging: Protocol Development and Quality Assurance Issues for Medical Imaging in Clinical Trials H. Cecil Charles, Ph.D. Director Duke Image Analysis Laboratory Duke University Medical Center
Overview • Quantitative Imaging vs: Clinical Imaging • Protocol Development Issues • Centrally Monitored QC/QA in multi-center trials • Central Data Analysis/Archival Issues
What Is Quantitative Imaging (QI) and How Is It Different From Clinical Imaging (CI)?
Visualization of lesions and/or disease Radiologic interpretation Rule-out or rule-in a diagnosis Diagnostic tree/1°,2°,3° diagnosis Determination of tissue characteristics from imaging parameters Algorithm/SOP/scaled interpretation Numeric output Incorporation in hypothesis testing or goal driven evaluation CI QI Effect Monitoring Diagnosis
Is there a use for CI in trials • If imaging is part of the diagnostic inclusion or exclusion criteria, a screening scan may be required • The screening scan may or may not be according to the QI protocol • Subsequent imaging sessions (including a baseline scan) are based on the QI protocol
Organ volumes or Subvolumes Perfusion/Permeability/blood flow Atrophy indices Necrosis/Hypoxia Indices Metabolic Indices (e.g. pH, energetics) Ligand Binding Vascular Indices Examples of QI
ISSUES for QI • Study Protocol Design • Data Quality • Data Format Issues • Data “Cleaning” • Data Registration (serial studies) • Data Analysis • Data Archival
Study Protocol: General • Driven by Study goals and QI Algorithm(s) (Analyses) • Maximize Information Content per unit time • Deterministic Figure of Merit (FOM) • CNR/(unit resolution * unit time) • Patient Comfort/Compliance
Multiple Sites/Platforms • Imaging protocol cross-validation • Rationalize Nomenclature • “Uniform” site training tailored to manufacturer/HW/SW status • Retrain with upgrades if necessary • Centrally monitored protocol compliance (QC)
Data Quality Assessment • SNR/CNR • Artifacts (e.g. Motion) [quantitative criteria: clutter/noise] • Protocol Adherence • Scan Parameters • Schedule • Technical Parameters (e.g. contrast dose and rate) • System Performance • Spatial Fidelity! (esp. in serial studies)
Incoming Data Formats • Native data from multiple manufacturers and multiple S/W releases • Varying Media Formats • MOD’s, DAT(s), CDROM(s) • Varying File Formats • DICOM(s) • Proprietary Formats • ACR/NEMA • “Local” formats (non-commercial PACS)
Data Storage Formats • Imaging Industry “standards” • DICOM (a flexible standard) • Alternate Standards • (e.g. Analyze, TIFF)
Data Cleaning • Prospective QC • Rescan if possible • Minimization of Lost Data • Data Rejection • Quantitative Basis! • Site Notification
Data Registration • Minimize positioning errors in protocol • Use Immobilizers to alleviate motion • REGISTER serial scans
Data Registration • Even with on site training and quality technologists, some misalignment will occur in serial studies • Alignment of the datasets minimizes the impact of this problem
Data Analysis • Prospective Criteria based on needs of study • Optimize FOM and QC criteria to match needs of algorithm • SOP • Replicate analysis to address drift
Data Archival • Driven by needs of sponsor and regulatory agencies • Central Consolidation and Storage • Coordinating Center Archival
Summary • Close Intellectual and technological relationship among the sponsor, imaging site(s) and imaging coordinating center • Ongoing QC/QA • Blinded quantitative data analysis • Regulatory compliance