Table 1. Study design.

Phase	Aim(s)	Methods	Samples/Animals
1	Describing equine echographic bronchial anatomy	NPE	26 bronchial samples from lungs of 6 slaughtered horses*
2	Comparing measures of interest performed with EBUS and histology	EBUS and histology	109 bronchial samples from lungs of 13 slaughtered horses*
3	Ex vivo technique optimization and “proof of concept”	EBUS on isolated lungs	lungs from 4 horses with heaves and 7 controls
4	In vivo EBUS	EBUS on horses	4 horses with heaves and 3 controls
5	Validation a. assessing the effect of lung removal from the thorax (collapse) on EBUS; b. histological validation.	EBUS and histology on post-mortem specimens of horses studied in phase 4	same horses studied in phase 4

* Lungs with obvious macroscopic alterations were excluded from the study. NPE: needle puncture experiments; EBUS: endobronchial ultrasound.