Table 2.

Comparison of image-derived volumes and metrics of small-vessel density as well as regional density measures in CTEPH and control groups

	CTEPH	Control	P valuea
Lung volume, L
Right lung	2.16 (1.44–2.63)	1.87 (1.59–2.32)	0.58
Left lung	1.5 (1.25–2.15)	1.76 (1.32–2.07)	0.73
Total blood volume density TBV/lung volume, mL vessel/dL lung
Whole lung	6.0 (5.6–7.2)	6.0 (4.9–6.7)	0.38
Right lung	6.4 (5.6–7.3)	5.9 (4.9–6.8)	0.26
Left lung	6.1 (5.6–7.1)	5.9 (4.8–7.1)	0.49
Small-vessel volume fraction, BV5/TBV
Whole lung	0.45 (0.34–0.49)	0.58 (0.46–0.62)	0.0007
Right lung	0.47 (0.38–0.53)	0.59 (0.54–0.64)	0.0010
Left lung	0.41 (0.27–0.46)	0.57 (0.47–0.62)	0.0009
Large-vessel volume fraction, BV>10/TBV
Whole lung	0.35 (0.32–0.40)	0.28 (0.24–0.34)	0.0009
Right lung	0.34 (0.31–0.45)	0.26 (0.24–0.29)	0.0006
Left lung	0.36 (0.33–0.43)	0.29 (0.24–0.33)	0.002
Small-vessel density ρBV5, mL vessel/dL lung
Whole lung	2.7 (2.5–3.0)	3.2 (3.0–3.8)	0.008
Right lung	2.9 (2.5–3.3)	3.2 (3.1–3.9)	0.04
Left lung	2.5 (2.0–2.8)	3.1 (2.7–3.7)	0.002
Large-vessel density ρBV>10, mL vessel/dL lung
Whole lung	2.5 (1.8–2.8)	1.8 (1.4–2.0)	0.008
Right lung	2.4 (1.7–2.8)	1.7 (1.2–2.1)	0.006
Left lung	2.5 (1.8–2.9)	1.6 (1.5–2.2)	0.009

^NoteData reported as median (interquartile range). BV>10: volume of vessels with cross-sectional area > 10 mm². BV5: volume of vessels with cross-sectional area ≤ 5 mm²; CTEPH: chronic thromboembolic pulmonary hypertension; TBV: total volume of blood vessels detected; ρBV5: BV5/total lung volume; ρBV>10: BV>10/total lung volume.

^aP value based on a Wilcoxon exact test with a 2-sided P value.