[ENH] BEP001 - New entity: flip

src/99-appendices/09-entities.md

@@ -106,7 +106,8 @@ Full name: Phase-Encoding Direction
 Format: `dir-<label>`
 
 Definition: The `dir-<label>` key/value can be set to an arbitrary alphanumeric label
-(for example, `dir-LR` or `dir-AP`) to distinguish different phase-encoding directions.
+(for example, `dir-LR` or `dir-AP`) to distinguish different phase-encoding
+directions.
 
 ## run
 
@@ -135,12 +136,26 @@ Full name: Echo
 
 Format: `echo-<index>`
 
-Definition: Multi-echo data MUST be split into one file per echo.
-Each file shares the same name with the exception of the `_echo-<index>`
-key/value.
-Please note that the `<index>` denotes the number/index (in the form of a
-nonnegative integer) of the echo not the echo time value which needs to be
-stored in the field `EchoTime` of the separate JSON file.
+Definition: If files belonging to an entity-linked file collection are acquired at different
+echo times, the `_echo-<index>` key/value pair MUST be used to distinguish
+individual files.
+This entity represents the `EchoTime` metadata field. Please note that the `<index>`
+denotes the number/index (in the form of a nonnegative integer), not the
+`EchoTime` value which needs to be stored in the field `EchoTime` of the separate
+JSON file.
+
+## flip
+
+Full name: Flip Angle
+
+Format: `flip-<index>`
+
+Definition: If files belonging to an entity-linked file collection are acquired at different
+flip angles, the `_flip-<index>` key/value pair MUST be used to distinguish
+individual files.
+This entity represents the `FlipAngle` metadata field. Please note that the `<index>`
+denotes the number/index (in the form of a nonnegative integer), not the `FlipAngle`
+value which needs to be stored in the field `FlipAngle` of the separate JSON file.
 
 ## recording
 

src/schema/entities.yaml

@@ -102,12 +102,24 @@ echo:
   name: Echo
   entity: echo
   description: |
-    Multi-echo data MUST be split into one file per echo.
-    Each file shares the same name with the exception of the `_echo-<index>`
-    key/value.
-    Please note that the `<index>` denotes the number/index (in the form of a
-    nonnegative integer) of the echo not the echo time value which needs to be
-    stored in the field `EchoTime` of the separate JSON file.
+    If files belonging to an entity-linked file collection are acquired at different
+    echo times, the `_echo-<index>` key/value pair MUST be used to distinguish
+    individual files.
+    This entity represents the `EchoTime` metadata field. Please note that the `<index>`
+    denotes the number/index (in the form of a nonnegative integer), not the
+    `EchoTime` value which needs to be stored in the field `EchoTime` of the separate
+    JSON file.
+  format: index
+flip:
+  name: Flip Angle
+  entity: flip
+  description: |
+    If files belonging to an entity-linked file collection are acquired at different
+    flip angles, the `_flip-<index>` key/value pair MUST be used to distinguish
+    individual files.
+    This entity represents the `FlipAngle` metadata field. Please note that the `<index>`
+    denotes the number/index (in the form of a nonnegative integer), not the `FlipAngle`
+    value which needs to be stored in the field `FlipAngle` of the separate JSON file.
   format: index
 recording:
   name: Recording

tools/bids_schema.py

@@ -224,8 +224,7 @@ def save_entities(schema_path, out_file):
             fo.write('\n\n')
             fo.write('Full name: {}'.format(entity_info['name']))
             fo.write('\n\n')
-            fo.write('Format: `{}-<{}>`'.format(entity_info['entity'],
-                                                entity_info['format']))
+            fo.write('Format: `{}-<{}>`'.format(entity_info['entity'], entity_info['format']))
             fo.write('\n\n')
             fo.write('Definition: {}'.format(entity_info['description']))