Bronchus sign on thin-section computed tomography is a powerful predictive factor for successful transbronchial biopsy using endobronchial ultrasound with a guide sheath for small peripheral lung lesions: a retrospective observational study

Table 4 Contribution of clinical factors available before bronchoscopy to diagnostic yield (all cases)

Variables		Diagnostic yield	p value
Lesion diameter	<20 mm	51/80 (63.8 %)	0.01*
Lesion diameter	≥20 mm	57/69 (82.6 %)
Lesion location	Upper lobe or sup segment of lower lobe	40/56 (71.4 %)	0.82
Lesion location	Middle or lower lobe ^a	68/93 (73.1 %)
Feature of the lesion	GGO	12/18 (66.7 %)	0.24
Feature of the lesion	Solid	96/131 (73.2 %)
Visibility of the lesion on Chest X-ray	Clearly visible	59/72 (81.9 %)	0.01*
Visibility of the lesion on Chest X-ray	Vague or invisible	49/77 (63.6 %)
Number of bronchial branch to reach the lesion	≥5	35/50 (70.0 %)	0.63
Number of bronchial branch to reach the lesion	≤4	73/99 (73.7 %)
Operator’s experience (years)	≥7	34/52 (65.4 %)	0.16
Operator’s experience (years)	≤6	74/97 (76.3 %)
CT bronchus sign^b	A	72/86 (83.7 %)	0.001*
	B	32/49 (65.3 %)
	C	4/14 (28.6 %)

* significant difference, ^a except for superior segment of the lower lobe, ^b See Methods

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