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SPIE Medical Imaging Conference Lung Imaging Database Consortium (LIDC) LIDC Data Elements and Data Collection Process February 13, 2005
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The Database The Database will contain:The Database will contain: 1) A collection of CT scan images
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1 Low Dose Lung Cancer Screen CTs
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The Database CT scan image dataCT scan image data a)Low Dose, Full Chest Lung Cancer Screening CTs b)Conventional Dose, Full Chest CTs (Retrospective Cases, e.g. Lung Ca Patients) c)Conventional Dose, Limited Chest CTs (e.g. Scan of a single nodule; biopsy) All image data in DICOM formatAll image data in DICOM format Indexing to identify cases of each typeIndexing to identify cases of each type
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The Database The database will contain:The database will contain: 1) A collection of CT scan images 2) Technical factors about the CT scan
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The Database Technical factors about the CT scanTechnical factors about the CT scan All Image data will be anonymizedAll Image data will be anonymized Much of DICOM header info will be preserved and stored along with image dataMuch of DICOM header info will be preserved and stored along with image data Database fields (can be queried) will have Non-patient information from DICOM headerDatabase fields (can be queried) will have Non-patient information from DICOM header
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The Database Technical factors about the CT scanTechnical factors about the CT scan Technical factors such as:Technical factors such as: kVpkVp Tube currentTube current Rotation timeRotation time ExposureExposure Reconstructed slice thickness and slice location (will still have to calc. spacing)Reconstructed slice thickness and slice location (will still have to calc. spacing) Reconstruction algorithmReconstruction algorithm Reconstructed field of view, pixel sizeReconstructed field of view, pixel size Content in private fields WILL BE removedContent in private fields WILL BE removed
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The Database The database will contain:The database will contain: 1) A collection of CT scan images 2) Technical factors about the CT scan 3) Nodule Markings and Descriptions
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The Database Nodule Markings and DescriptionsNodule Markings and Descriptions 1) For Nodules > 3 mm diameter Radiologist drawn boundariesRadiologist drawn boundaries Description of characteristics (from defined list)Description of characteristics (from defined list) 2) For Nodules < 3 mm Radiologist marks only centroidRadiologist marks only centroid No description characteristicsNo description characteristics
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Nodule Marking Initial Approach Multiple Reads with Multiple Readers Multiple Reads with Multiple Readers First Read – 4 readers, each reads independently (Blinded) First Read – 4 readers, each reads independently (Blinded) Compile 4 blinded reads and distribute to readers Compile 4 blinded reads and distribute to readers Second Read – Same 4 readers, this time unblinded to the results of the other readers from the first reading. Second Read – Same 4 readers, this time unblinded to the results of the other readers from the first reading. No forced consensus on either location of nodules nor on their boundaries. No forced consensus on either location of nodules nor on their boundaries.
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Blinded Reads – Each Reader Reads Independently (Blinded to Results of Other Readers)
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Reader 1 Blinded Read for Reader 1 – Marks Only One Nodule
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Reader 2 Blinded Read for Reader 2 – Marks Two Nodules (Note: One nodule is same as Reader 1)
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Reader 3 Blinded Read for Reader 3 – Marks Two Nodules (Note: Again, One nodule is same as for Reader 1)
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Reader 4 Blinded Read for Reader 4 – Did Not Mark Any Nodules
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2 nd Round - UnBlinded Reads Readings in Which Readers Are Shown Results of Other Readers Each Reader Marks Nodules After Being Shown Results From Their Own and Other Readers’ Blinded Reads (Each Reader Decides to Include or Ignore).
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Reader 1 Unblinded Read for Reader 1 – Now Marks Two Nodules (Originally only marked one)
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Reader 2 Unblinded Read for Reader 2 – Still Marks Two Nodules (No Change)
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Reader 3 Unblinded Read for Reader 3 – Now Marks Three Nodules (Originally only marked two)
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Reader 4 Unblinded Read for Reader 4 – Now Marks Three Nodules (Originally did not mark any)
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4/4 Markings 2/4 Markings Results of Unblinded Reads from All Four Readers We will capture one aspect of reader variability in this way
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Case 5, Slice 19
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Radiologist 1 - Method 1
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Radiologist 1 - Method 2
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Radiologist 1 - Method 3
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Radiologist 2 - Method 1
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Radiologist 2 - Method 3
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Radiologist 3 - Method 1
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Radiologist 3 - Method 2
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Radiologist 3 - Method 3
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Radiologist 4 - Method 1
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Radiologist 4 - Method 2
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Radiologist 4 - Method 3
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Radiologist 5 - Method 1
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Radiologist 5 - Method 3
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Probabilistic Description of Boundary
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Apply Threshold if Desired
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The Database The database will contain:The database will contain: 1) A collection of CT scan images 2) Technical factors about the CT scan 3) Nodule Markings and Descriptions 4) Pathology results or diagnosis information whenever available
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Pathology Information In those cases in which pathology is available, we will extract from reports: Whether histology or cytology was performed Whether histology or cytology was performed If histology, try to establish the cell type according to WHO classifications If histology, try to establish the cell type according to WHO classifications If cytology, establish whether it was benign or malignant If cytology, establish whether it was benign or malignant
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Pathology Information If no pathology, other diagnostic information may be substituted when available (such as 2 years Dx F/U with no change in radiographic appearance). If no pathology, other diagnostic information may be substituted when available (such as 2 years Dx F/U with no change in radiographic appearance). If neither is available, then case will be used for detection purposes only. If neither is available, then case will be used for detection purposes only.
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Summary LIDC Data Elements LIDC Data Elements Image Data Image Data Technical Factors Technical Factors Radiologists’ Contours of Nodules Radiologists’ Contours of Nodules Data Collection Process Data Collection Process Diagnosis Information where available Diagnosis Information where available
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