diff --git a/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md b/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md
index f52e2b38ea..5b7312a47b 100644
--- a/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md
+++ b/src/04-modality-specific-files/01-magnetic-resonance-imaging-data.md
@@ -127,7 +127,7 @@ Template:
 ```Text
 sub-<label>/[ses-<label>/]
     anat/
-        sub-<label>[_ses-<label>][_acq-<label>][_ce-<label>][_rec-<label>][_run-<index>]_<modality_label>.nii[.gz]
+        sub-<label>[_ses-<label>][_acq-<label>][_ce-<label>][_rec-<label>][_run-<index>][_part-<label>]_<modality_label>.nii[.gz]
         sub-<label>[_ses-<label>][_acq-<label>][_ce-<label>][_rec-<label>][_run-<index>][_mod-<label>]_defacemask.nii[.gz]
 ```
 
@@ -195,6 +195,37 @@ fields specific to anatomical scans:
 | ----------------------- | --------------------- | ------------- | ---------------------------------------------------------------------------------------------------------------------------------------- |
 | ContrastBolusIngredient | OPTIONAL              | [string][]    | Active ingredient of agent. Values MUST be one of: IODINE, GADOLINIUM, CARBON DIOXIDE, BARIUM, XENON Corresponds to DICOM Tag 0018,1048. |
 
+The [`part-<label>`](../99-appendices/09-entities.md#part) key/value pair is
+used to indicate which component of the complex representation of the MRI
+signal is represented in voxel data.
+This entity is associated with the DICOM tag `0008,9208`.
+Allowed label values for this entity are `phase`, `mag`, `real` and `imag`,
+which are typically used in `part-mag`/`part-phase` or `part-real`/`part-imag`
+pairs of files.
+For example:
+
+```Text
+sub-01_part-mag_T1w.nii.gz
+sub-01_part-mag_T1w.json
+sub-01_part-phase_T1w.nii.gz
+sub-01_part-phase_T1w.json
+```
+
+Phase images MAY be in radians or in arbitrary units.
+The sidecar JSON file MUST include the units of the `phase` image.
+The possible options are `rad` or `arbitrary`.
+For example:
+
+sub-01_part-phase_T1w.json
+
+```Text
+{
+   "Units": "rad"
+}
+```
+
+When there is only a magnitude image of a given type, the `part` key MAY be omitted.
+
 Similarly, the OPTIONAL [`rec-<label>`](../99-appendices/09-entities.md#rec)
 key/value can be used to distinguish
 different reconstruction algorithms (for example ones using motion correction).
@@ -203,19 +234,20 @@ different reconstruction algorithms (for example ones using motion correction).
 
 Currently supported image contrasts include:
 
-| **Name**  | `contrast_label` | **Description**                                                                                      |
-|---------- | ---------------- | ---------------------------------------------------------------------------------------------------- |
-| BOLD      | bold             | Blood-Oxygen-Level Dependent contrast (specialized T2\* weighting)                                   |
-| CBV       | cbv              | Cerebral Blood Volume contrast (specialized T2\* weighting or difference between T1 weighted images) |
-| Phase     | phase            | Phase information associated with magnitude information stored in BOLD contrast                      |
+| **Name**  | `suffix` | **Description**                                                                                                                                                                                                                                                          |
+|---------- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| BOLD      | bold     | Blood-Oxygen-Level Dependent contrast (specialized T2\* weighting)                                                                                                                                                                                                       |
+| CBV       | cbv      | Cerebral Blood Volume contrast (specialized T2\* weighting or difference between T1 weighted images)                                                                                                                                                                     |
+| Phase     | phase    | [DEPRECATED](../02-common-principles.md#definitions). Phase information associated with magnitude information stored in BOLD contrast. This suffix should be replaced by the [`part-phase`](../99-appendices/09-entities.md#part) in conjunction with the `bold` suffix. |
 
 Template:
 
 ```Text
 sub-<label>/[ses-<label>/]
     func/
-        sub-<label>[_ses-<label>]_task-<label>[_acq-<label>][_ce-<label>][_dir-<label>][_rec-<label>][_run-<index>][_echo-<index>]_<contrast_label>.nii[.gz]
-        sub-<label>[_ses-<label>]_task-<label>[_acq-<label>][_ce-<label>][_dir-<label>][_rec-<label>][_run-<index>][_echo-<index>]_sbref.nii[.gz]
+        sub-<label>[_ses-<label>]_task-<label>[_acq-<label>][_ce-<label>][_dir-<label>][_rec-<label>][_run-<index>][_echo-<index>][_part-<label>]_bold.nii[.gz]
+        sub-<label>[_ses-<label>]_task-<label>[_acq-<label>][_ce-<label>][_dir-<label>][_rec-<label>][_run-<index>][_echo-<index>][_part-<label>]_cbv.nii[.gz]
+        sub-<label>[_ses-<label>]_task-<label>[_acq-<label>][_ce-<label>][_dir-<label>][_rec-<label>][_run-<index>][_echo-<index>][_part-<label>]_sbref.nii[.gz]
 ```
 
 Functional imaging consists of techniques that support rapid temporal repetition.
@@ -283,7 +315,30 @@ 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.
 
-Some meta information about the acquisition MUST be provided in an additional
+Complex-valued data MUST be split into one file for each data type.
+For BOLD data, there are separate suffixes for magnitude (`_bold`) and phase
+(`_phase`) data, but the `_phase` suffix is [deprecated](../02-common-principles.md#definitions).
+Newly generated datasets SHOULD NOT use the `_phase` suffix, and the suffix will be removed
+from the specification in the next major release.
+For backwards compatibility, `_phase` is considered equivalent to `_part-phase_bold`.
+When the `_phase` suffix is not used, each file shares the same
+name with the exception of the `part-<mag|phase>` or `part-<real|imag>` key/value.
+For example:
+
+```Text
+sub-01/
+   func/
+      sub-01_task-cuedSGT_part-mag_bold.nii.gz
+      sub-01_task-cuedSGT_part-mag_bold.json
+      sub-01_task-cuedSGT_part-phase_bold.nii.gz
+      sub-01_task-cuedSGT_part-phase_bold.json
+      sub-01_task-cuedSGT_part-mag_sbref.nii.gz
+      sub-01_task-cuedSGT_part-mag_sbref.json
+      sub-01_task-cuedSGT_part-phase_sbref.nii.gz
+      sub-01_task-cuedSGT_part-phase_sbref.json
+```
+
+Some meta information about the acquisition MUST be provided in an additional
 JSON file.
 
 ### Required fields
@@ -389,12 +444,12 @@ Template:
 ```Text
 sub-<label>/[ses-<label>/]
     dwi/
-       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>]_dwi.nii[.gz]
-       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>]_dwi.bval
-       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>]_dwi.bvec
-       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>]_dwi.json
-       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>]_sbref.nii[.gz]
-       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>]_sbref.json
+       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>][_part-<label>]_dwi.nii[.gz]
+       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>][_part-<label>]_dwi.bval
+       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>][_part-<label>]_dwi.bvec
+       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>][_part-<label>]_dwi.json
+       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>][_part-<label>]_sbref.nii[.gz]
+       sub-<label>[_ses-<label>][_acq-<label>][_dir-<label>][_run-<index>][_part-<label>]_sbref.json
 ```
 
 If more than one run of the same acquisition and direction has been acquired, the
diff --git a/src/99-appendices/04-entity-table.md b/src/99-appendices/04-entity-table.md
index 9f3002bf33..f9ae4bd520 100644
--- a/src/99-appendices/04-entity-table.md
+++ b/src/99-appendices/04-entity-table.md
@@ -18,16 +18,17 @@ while entity definitions are in [Appendix IX](09-entities.md).
 
 ## Magnetic Resonance Imaging
 
-| Entity                                                                                         | Subject                             | Session                             | Task                                  | Acquisition                         | Contrast Enhancing Agent          | Reconstruction                      | Phase-Encoding Direction            | Run                                 | Corresponding Modality              | Echo                                  | Recording                                       |
-|------------------------------------------------------------------------------------------------|-------------------------------------|-------------------------------------|---------------------------------------|-------------------------------------|-----------------------------------|-------------------------------------|-------------------------------------|-------------------------------------|-------------------------------------|---------------------------------------|-------------------------------------------------|
-| Format                                                                                         | [`sub-<label>`](09-entities.md#sub) | [`ses-<label>`](09-entities.md#ses) | [`task-<label>`](09-entities.md#task) | [`acq-<label>`](09-entities.md#acq) | [`ce-<label>`](09-entities.md#ce) | [`rec-<label>`](09-entities.md#rec) | [`dir-<label>`](09-entities.md#dir) | [`run-<index>`](09-entities.md#run) | [`mod-<label>`](09-entities.md#mod) | [`echo-<index>`](09-entities.md#echo) | [`recording-<label>`](09-entities.md#recording) |
-| anat<br>(T1w T2w T1rho T1map T2map T2star FLAIR FLASH PD PDmap PDT2 inplaneT1 inplaneT2 angio) | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            | OPTIONAL                          | OPTIONAL                            |                                     | OPTIONAL                            |                                     |                                       |                                                 |
-| anat<br>(defacemask)                                                                           | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            | OPTIONAL                          | OPTIONAL                            |                                     | OPTIONAL                            | OPTIONAL                            |                                       |                                                 |
-| dwi<br>(dwi sbref)                                                                             | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            |                                   |                                     | OPTIONAL                            | OPTIONAL                            |                                     |                                       |                                                 |
-| fmap<br>(phasediff phase1 phase2 magnitude1 magnitude2 magnitude fieldmap)                     | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            |                                   |                                     |                                     | OPTIONAL                            |                                     |                                       |                                                 |
-| fmap<br>(epi)                                                                                  | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            | OPTIONAL                          |                                     | REQUIRED                            | OPTIONAL                            |                                     |                                       |                                                 |
-| func<br>(bold cbv phase sbref events)                                                          | REQUIRED                            | OPTIONAL                            | REQUIRED                              | OPTIONAL                            | OPTIONAL                          | OPTIONAL                            | OPTIONAL                            | OPTIONAL                            |                                     | OPTIONAL                              |                                                 |
-| func<br>(physio stim)                                                                          | REQUIRED                            | OPTIONAL                            | REQUIRED                              | OPTIONAL                            |                                   | OPTIONAL                            |                                     | OPTIONAL                            |                                     |                                       | OPTIONAL                                        |
+| Entity                                                                                         | Subject                             | Session                             | Task                                  | Acquisition                         | Contrast Enhancing Agent          | Reconstruction                      | Phase-Encoding Direction            | Run                                 | Corresponding Modality              | Echo                                  | Recording                                       | Part                                  |
+|------------------------------------------------------------------------------------------------|-------------------------------------|-------------------------------------|---------------------------------------|-------------------------------------|-----------------------------------|-------------------------------------|-------------------------------------|-------------------------------------|-------------------------------------|---------------------------------------|-------------------------------------------------|---------------------------------------|
+| Format                                                                                         | [`sub-<label>`](09-entities.md#sub) | [`ses-<label>`](09-entities.md#ses) | [`task-<label>`](09-entities.md#task) | [`acq-<label>`](09-entities.md#acq) | [`ce-<label>`](09-entities.md#ce) | [`rec-<label>`](09-entities.md#rec) | [`dir-<label>`](09-entities.md#dir) | [`run-<index>`](09-entities.md#run) | [`mod-<label>`](09-entities.md#mod) | [`echo-<index>`](09-entities.md#echo) | [`recording-<label>`](09-entities.md#recording) | [`part-<label>`](09-entities.md#part) |
+| anat<br>(T1w T2w T1rho T1map T2map T2star FLAIR FLASH PD PDmap PDT2 inplaneT1 inplaneT2 angio) | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            | OPTIONAL                          | OPTIONAL                            |                                     | OPTIONAL                            |                                     |                                       |                                                 | OPTIONAL                              |
+| anat<br>(defacemask)                                                                           | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            | OPTIONAL                          | OPTIONAL                            |                                     | OPTIONAL                            | OPTIONAL                            |                                       |                                                 |                                       |
+| dwi<br>(dwi sbref)                                                                             | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            |                                   |                                     | OPTIONAL                            | OPTIONAL                            |                                     |                                       |                                                 | OPTIONAL                              |
+| fmap<br>(phasediff phase1 phase2 magnitude1 magnitude2 magnitude fieldmap)                     | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            |                                   |                                     |                                     | OPTIONAL                            |                                     |                                       |                                                 |                                       |
+| fmap<br>(epi)                                                                                  | REQUIRED                            | OPTIONAL                            |                                       | OPTIONAL                            | OPTIONAL                          |                                     | REQUIRED                            | OPTIONAL                            |                                     |                                       |                                                 |                                       |
+| func<br>(bold cbv sbref)                                                                       | REQUIRED                            | OPTIONAL                            | REQUIRED                              | OPTIONAL                            | OPTIONAL                          | OPTIONAL                            | OPTIONAL                            | OPTIONAL                            |                                     | OPTIONAL                              |                                                 | OPTIONAL                              |
+| func<br>(phase events)                                                                         | REQUIRED                            | OPTIONAL                            | REQUIRED                              | OPTIONAL                            | OPTIONAL                          | OPTIONAL                            | OPTIONAL                            | OPTIONAL                            |                                     | OPTIONAL                              |                                                 |                                       |
+| func<br>(physio stim)                                                                          | REQUIRED                            | OPTIONAL                            | REQUIRED                              | OPTIONAL                            |                                   | OPTIONAL                            |                                     | OPTIONAL                            |                                     |                                       | OPTIONAL                                        |                                       |
 
 ## Encephalography (EEG, iEEG, and MEG)
 
diff --git a/src/99-appendices/09-entities.md b/src/99-appendices/09-entities.md
index 5ab5d57a73..b0c1e7a9fb 100644
--- a/src/99-appendices/09-entities.md
+++ b/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
 
@@ -153,6 +154,27 @@ sampling frequencies).
 In such case use different labels.
 For example: `_recording-contrast`, `_recording-saturation`.
 
+## part
+
+Full name: Part
+
+Format: `part-<label>`
+
+Definition: This entity is used to indicate which component of the complex
+representation of the MRI signal is represented in voxel data.
+The `part-<label>` key/value pair is associated with the DICOM tag
+`0008,9208`.
+Allowed label values for this entity are `phase`, `mag`, `real` and `imag`,
+which are typically used in `part-mag`/`part-phase` or
+`part-real`/`part-imag` pairs of files.
+
+Phase images MAY be in radians or in arbitrary units.
+The sidecar JSON file MUST include the units of the `phase` image.
+The possible options are `rad` or `arbitrary`.
+
+When there is only a magnitude image of a given type, the `part` key MAY be
+omitted.
+
 ## proc
 
 Full name: Processed (on device)
diff --git a/src/schema/datatypes/anat.yaml b/src/schema/datatypes/anat.yaml
index bae17648ce..e0b8bad9fb 100644
--- a/src/schema/datatypes/anat.yaml
+++ b/src/schema/datatypes/anat.yaml
@@ -26,6 +26,7 @@
     acq: optional
     ce: optional
     rec: optional
+    part: optional
 # Second group
 - suffixes:
     - defacemask
diff --git a/src/schema/datatypes/dwi.yaml b/src/schema/datatypes/dwi.yaml
index 26f78761cf..291db298e9 100644
--- a/src/schema/datatypes/dwi.yaml
+++ b/src/schema/datatypes/dwi.yaml
@@ -14,6 +14,7 @@
     acq: optional
     dir: optional
     run: optional
+    part: optional
 # Second group
 - suffixes:
     - sbref
@@ -27,3 +28,4 @@
     acq: optional
     dir: optional
     run: optional
+    part: optional
diff --git a/src/schema/datatypes/func.yaml b/src/schema/datatypes/func.yaml
index 62a26b60b8..8c99a3689d 100644
--- a/src/schema/datatypes/func.yaml
+++ b/src/schema/datatypes/func.yaml
@@ -3,7 +3,6 @@
 - suffixes:
     - bold
     - cbv
-    - phase
     - sbref
   extensions:
     - .nii.gz
@@ -19,7 +18,25 @@
     dir: optional
     run: optional
     echo: optional
+    part: optional
 # Second group
+- suffixes:
+    - phase
+  extensions:
+    - .nii.gz
+    - .nii
+    - .json
+  entities:
+    sub: required
+    ses: optional
+    task: required
+    acq: optional
+    ce: optional
+    rec: optional
+    dir: optional
+    run: optional
+    echo: optional
+# Third group
 - suffixes:
     - events
   extensions:
@@ -35,7 +52,7 @@
     dir: optional
     run: optional
     echo: optional
-# Third group
+# Fourth group
 - suffixes:
     - physio
     - stim
diff --git a/src/schema/entities.yaml b/src/schema/entities.yaml
index 86471b1d8f..dbeffa98b7 100644
--- a/src/schema/entities.yaml
+++ b/src/schema/entities.yaml
@@ -118,6 +118,25 @@ recording:
     In such case use different labels.
     For example: `_recording-contrast`, `_recording-saturation`.
   format: label
+part:
+  name: Part
+  entity: part
+  description: |
+    This entity is used to indicate which component of the complex
+    representation of the MRI signal is represented in voxel data.
+    The `part-<label>` key/value pair is associated with the DICOM tag
+    `0008,9208`.
+    Allowed label values for this entity are `phase`, `mag`, `real` and `imag`,
+    which are typically used in `part-mag`/`part-phase` or
+    `part-real`/`part-imag` pairs of files.
+
+    Phase images MAY be in radians or in arbitrary units.
+    The sidecar JSON file MUST include the units of the `phase` image.
+    The possible options are `rad` or `arbitrary`.
+
+    When there is only a magnitude image of a given type, the `part` key MAY be
+    omitted.
+  format: label
 processing:
   name: Processed (on device)
   entity: proc