MIMIC-IV-ECHO-Ext-LVVOLUMES-A4C-ROI: Annotated Subset of Apical Four-Chamber Echocardiography for PoCUS-Style LV Volume and Function Analysis

**MIMIC-IV-ECHO-Ext-LVVOLUMES-A4C-ROI** is a curated, credentialed subset of
_MIMIC-IV-ECHO v0.1_ focusing on apical four-chamber (A4C) echocardiographic
views with accompanying left-ventricular volumetric labels. The release
includes 1,064 de-identified A4C DICOM video sequences from 806 unique
patients, each paired with a manually annotated region-of-interest (ROI) mask
in both PNG and JSON formats at the original DICOM 4D resolution. ROI-applied,
downsampled (256 × 256) MP4 and NPZ derivatives are provided for efficient
model development. The full-resolution masks preserve native geometry,
enabling regeneration of higher-resolution datasets directly from the source
DICOMs.

This resource supports three primary use cases: (i) as an _out-of-distribution
(OOD) PoCUS external test set_ for evaluating state-of-the-art LV volume and
ejection fraction (EF) models trained on laboratory echocardiography; (ii)
_training and benchmarking ROI segmentation models_ for background and overlay
removal; and (iii) _developing LV-focused video models_ using preprocessed
MP4/NPZ inputs that eliminate DICOM parsing overhead.

Both single-plane (A4C) and biplane (BP) volumetric and EF labels are
included, enabling transparent comparison between monoplane interpretability
and biplane geometric precision. Access is provided under the PhysioNet
Credentialed Health Data License (v1.5.0).