Table 1. Overview of mean values and SD of measured Hounsfield units (HU) of CTs from PET/CT in different lung regions.

A gradient from anterior to posterior can be seen in both contrast-enhanced and non-contrast-enhanced CTs, pronounced between the middle and posterior regions. Values of contrast-enhanced CTs and non-contrast-enhanced CTs as well as the differences between the anterior and posterior regions did not differ significantly.

Hounsfield Units all patients (n = 15)
	Anterior	Middle	Posterior
Mean±SD	-779±64	-746±1	-685±118
Hounsfield Units contrast-enhanced CT (n = 8)
Mean±SD	-770±80	-732±86	679±128
Mean difference anterior-posterior: 94 HU
Hounsfield Units non-contrast-enhanced CT (n = 7)
Mean±SD	-788±40	-761±87	-691±108
Mean Difference anterior-posterior: 97 HU