LONI: Laboratory of Neuro Imaging

Quality Control for Data Integrity

ICBM has designed and implemented four different levels of quality assurance and quality control. These levels include checks for validity, type, and range of behavioral data, an explicit data entry/completeness check, a check of the integrity and completeness of the received data, and finally an in-depth verification of all received information.

Quality Control Stages

  • At each site, during and after the data entry. The behavioral data are checked automatically for validity, type, and range as the data are entered in the on-screen test forms. The MRI and PET scans are visually checked at the scanner consoles.
  • At each site, before the data is transferred to ICBM. For behavioral data, this includes an explicit data entry/completeness check. The tests are displayed in the order of administration, making it easier to monitor the data entry process. Once the user enters all the data for a certain Instrument he/she has to mark that the data entry is completed. This informs other users that the test's data entry is completed and disables anyone else but that user from editing the entered data. For MRI or PET data, this QC stage consists of a qualitative evaluation of the data using visualization software that allows multiple simultaneous cross-sectional views.

    Once a test's data entry or image acquisition has been completed and checked as such, the authorized user may evaluate the instrument and mark it as "Completed PASS" or "Completed FAILURE".

    If the instrument was not administered for some reason, it may be also checked as "Not Administered." Simultaneously, a record (related to the QC level) is updated, while an entry (comment) is inserted into the comment history table of the Database. Each time this is done, the QC flag table gets updated, keeping the latest entry, while the table comment history keeps the chronological listing of all comments.
  • At ICBM upon receipt of the data. This stage verifies the integrity and completeness of the received data and scans, i.e., if the received files were correctly transmitted, whether the data is complete, and whether the correct acquisition parameters were used. At this point the data are under quarantine.
  • At ICBM, following data receipt and integrity check. This level of Quality Control is the most comprehensive, in-depth verification of all received information. The validation at this QC level initiates the candidate's data "promotion" into the status of a full subject, when a study wide, unique Subject ID is assigned to it. For behavioral data, this involves a complete verification of all data against source documents (paper forms) on a random subset of candidates, and rapid data consistency checks of all data. For imaging data, this involves the qualitative and quantitative assessment of image quality