VolCT - Group 1B

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Current Goals & Status:

Question: What is the minimum detectable level of change in patient datasets under a “No Change” condition?

    • AIMS: For patient datasets acquired over a very short time interval (“no change” condition”) investigate variance in measuring change in volume, diameter and bi-directional diameters of lesions
    • Investigate inter-observer variability in each task
    • Investigate Intra-observer variability in each task
    • Methods - Materials
      • Image Data from MSK Coffee Break Experiment
      • 32 NSCLC patients, imaged twice on same scanner over period < 15 minutes
      • Thin slice (1.25 mm thick) image data
      • Selected one lesion per patient
      • no outcome data
      • Publicly Available on NCIA
    • Methods - Readings
      • 5 readers
      • Read CT at timepoint 1, CT at timepoint 2 and repeat either CT timepoint 1 or timeoint 2 to assess intra-reader variability
    • Methods - Measurements
      • Measure Single Longest Diameter, manually (SLD)
      • Measure Longest Diameter and Perpendicular Diameter; take product to obtain Product of Diameters (POD)
      • Contour Full Boundary of lesion with semiautomated tool; calculate volume (Vol)
      • Extract other measures as well (SLD from POD measureement; SLD from VOl and POD from Vol).
    • The Order of Readers, Lesions and Measurement Methods were Randomized (Measurements done in Blocks of 10)
    • Analyses
      • Pooled Analysis across readers and lesions; Percent Difference between Scan 1 and Scan 2 for each measurement method
      • Subgroup Analyses: (a) Based on Measureable/Non-Measureable lesions identified by Mike O'Neal of CoreLabs; (b) Difficult, Moderate and Easy as Identified by Mike McNitt-Gray
  • Conference Paper on Reproducibility and Accuracy of Uni- and Bi-Dimensional Tumor Measurements from MRI and CT Volumes, which looks at RECIST, WHO and Volume measurements.

Downloadable Images and Data Sets

Round 2 Images and Results

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