studies

JSON array

An array of imaging studies, with information about each study. An imaging study (or imaging session) is defined as a set of related series collected on a piece of equipment during a time period. An example is a research participant receiving an MRI exam. The participant goes into the scanner, has several MR images collected, and comes out. The time spent in the scanner and all of the data collected from it is considered to be a study.

Valid squirrel modalities are derived from the DICOM standard and from NiDB modalities. Modality can be any string, but some squirrel readers may not correctly interpret the modality or may convert it to “other” or “unknown”. See full list of modalities.

JSON variables

🔵 Primary key 🔴 Required 🟡 Computed (squirrel writer/reader should handle these variables)

Variable	Type	Default	Description
AgeAtStudy	number	🔴	Subject’s age in years at the time of the study.
Datetime	datetime	🔴	Date of the study.
DayNumber	number		For repeated studies and clinical trials, this indicates the day number of this study in relation to time 0.
Description	string	🔴	Study description.
Equipment	string		Equipment name, on which the imaging session was collected.
Height	number		Height in m of the subject at the time of the study.
Modality	string	🔴	Defines the type of data. See table of supported modalities.
StudyNumber	number	🔴 🔵	Study number. May be sequential or correspond to NiDB assigned study number.
StudyUID	string		DICOM field StudyUID.
TimePoint	number		Similar to day number, but this should be an ordinal number.
VisitType	string		Type of visit. ex: Pre, Post.
Weight	number		Weight in kg of the subject at the time of the study.
AnalysisCount	number	🟡	Number of analyses for this study.
SeriesCount	number	🟡	Number of series for this study.
VirtualPath	string	🟡	Relative path to the data within the package.
series	JSON array		Array of series.
analyses	JSON array		Array of analyses.

Directory structure

Files associated with this section are stored in the following directory. SubjectID and StudyNum are the actual subject ID and study number, for example /data/S1234ABC/1.

/data/<SubjectID>/<StudyNum>