BrainMask (Preclinical)
=======================

**Purpose.** Robust in-brain mask via thresholding + morphology (mricloud_inbrain-inspired).

Context I/O
-----------

- **Reads:** ``ImageCtr`` (X,Y,Z,NR), ``savedir``
- **Writes:** ``BrainMask`` (X,Y,Z)
- Optional: If ``relCBF`` is present, writes ``MaskedCBF.png`` (masked mosaic).

Parameters
----------

=================  ===================  ==========================================
Key                Type / Default       Meaning
=================  ===================  ==========================================
``thres``          float / ``0.2``      Threshold scale factor (mean-of-center-box × thres)
``open_iter``      int / ``2``          2D erosions per slice
``close_iter``     int / ``2``          2D dilations per slice
=================  ===================  ==========================================

YAML example
------------

.. code-block:: yaml

    modules:
      - name: BrainMask
        params:
          thres: 0.25
          open_iter: 2
          close_iter: 2