Appendix IV: Entity table

This section compiles the entities (key-value pairs) described throughout this specification, and establishes a common order within a filename. For example, if a file has an acquisition and reconstruction label, the acquisition entity must precede the reconstruction entity. REQUIRED and OPTIONAL entities for a given file type are denoted. Entity formats indicate whether the value is alphanumeric (<label>) or numeric (<index>).

A general introduction to entities is given in the section on file name structure

Entity	Subject	Session	Task	Acquisition	Contrast Enhancing Agent	Reconstruction	Phase-Encoding Direction	Run	Corresponding modality	Echo	Recording	Processed (on device)	Space
Format	sub-<label>	ses-<label>	task-<label>	acq-<label>	ce-<label>	rec-<label>	dir-<label>	run-<index>	mod-<label>	echo-<index>	recording-<label>	proc-<label>	space-<label>
anat (T1w T2w T1rho T1map T2map T2star FLAIR FLASH PD PDmap PDT2 inplaneT1 inplaneT2 angio)	REQUIRED	OPTIONAL		OPTIONAL	OPTIONAL	OPTIONAL
anat (defacemask)	REQUIRED	OPTIONAL		OPTIONAL	OPTIONAL	OPTIONAL			OPTIONAL
func (bold cbv phase sbref events)	REQUIRED	OPTIONAL	REQUIRED	OPTIONAL	OPTIONAL	OPTIONAL	OPTIONAL	OPTIONAL		OPTIONAL
func (physio stim)	REQUIRED	OPTIONAL	REQUIRED	OPTIONAL		OPTIONAL		OPTIONAL			OPTIONAL	OPTIONAL
dwi (dwi bvec bval)	REQUIRED	OPTIONAL		OPTIONAL			OPTIONAL	OPTIONAL
fmap (phasediff phase1 phase2 magnitude1 magnitude2 magnitude fieldmap)	REQUIRED	OPTIONAL		OPTIONAL				OPTIONAL
fmap (epi)	REQUIRED	OPTIONAL		OPTIONAL	OPTIONAL		REQUIRED	OPTIONAL
beh (events stim physio)	REQUIRED	OPTIONAL	REQUIRED
meg	REQUIRED	OPTIONAL	REQUIRED	OPTIONAL				OPTIONAL				OPTIONAL
eeg	REQUIRED	OPTIONAL	REQUIRED	OPTIONAL				OPTIONAL
ieeg	REQUIRED	OPTIONAL	REQUIRED	OPTIONAL				OPTIONAL
channels (meg/eeg/ieeg)	REQUIRED	OPTIONAL	REQUIRED					OPTIONAL
headshape (meg)	REQUIRED	OPTIONAL		OPTIONAL									OPTIONAL
markers (meg)	REQUIRED	OPTIONAL	OPTIONAL	OPTIONAL									OPTIONAL
photo (meg/eeg/ieeg)	REQUIRED	OPTIONAL		OPTIONAL
electrodes (eeg/ieeg)	REQUIRED	OPTIONAL		OPTIONAL									OPTIONAL
events (meg/eeg/ieeg)	REQUIRED	OPTIONAL	REQUIRED					OPTIONAL