From adb0e62a79f5b18cbe0761b88fda826f6a4f0770 Mon Sep 17 00:00:00 2001
From: Robert Smith <robert.smith@florey.edu.au>
Date: Wed, 15 May 2024 12:11:58 +1000
Subject: [PATCH] DWI models: Force presence of "param" entity

---
 src/derivatives/05-diffusion-derivatives.md | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/src/derivatives/05-diffusion-derivatives.md b/src/derivatives/05-diffusion-derivatives.md
index fc8d6633..0192c996 100644
--- a/src/derivatives/05-diffusion-derivatives.md
+++ b/src/derivatives/05-diffusion-derivatives.md
@@ -81,16 +81,6 @@ that warrant explicit mention due to their consequence in how they are represent
     they MUST also specify requisite metadata fields regarding
     how data across dimensions beyond the three spatial dimensions are to be interpreted.
 
-In cases where a pipeline yields only a single parameter from a model,
-entity "`_param-<label>`" MUST NOT be included; e.g.:
-```Text
-<pipeline_name>/
-    sub-<participant_label>/
-        dwi/
-            <source_keywords>[_space-<space>]_model-<label>_dwimap.nii[.gz]
-            <source_keywords>[_space-<space>]_model-<label>_dwimap.json
-```
-
 ### Orientation encoding types
 
 There are many mathematical bases that may be used
@@ -406,6 +396,10 @@ Dictionary `"ResponseFunction"` has the following reserved keywords:
         rather, it is the *diffusivity* that is the estimated parameter,
         and the *way in which the anisotropy of that parameter is encoded* is a tensor.
 
+    -   Even if image `sub-01_model-tensor_param-diffusivity_dwimap.nii.gz`
+        were to be the only image yielded by the pipeline,
+        it is nevertheless REQUIRED to include entity "`_param-`" in those file names.
+
     -   Metadata fields relevant to the interpretation of the anisotropy of the tensor
         are *not relevant* to the scalar measures
         "`s0`" (estimated signal intensity with no diffusion weighting)