How accurate are measurements of skin-lesion depths on prebiopsy supine chest computed tomography for transthoracic needle biopsies?

AimTo evaluate the accuracy of depth measurements on supine chest computed tomography (CT) for transthoracic needle biopsy (TNB).Materials and methodsWe measured skin-lesion depths from the skin surface to nodules on both prebiopsy supine CT scans and CT scans obtained during cone beam CT-guided TNB in the supine (n = 29) or prone (n = 40) position in 69 patients, and analyzed the differences between the two measurements, based on patient position for the biopsy and lesion location.ResultsSkin-lesion depths measured on prebiopsy supine CT scans were significantly larger than those measured on CT scans obtained during TNB in the prone position (p < 0.001; mean difference ± standard deviation (SD), 6.2 ± 5.7 mm; range, 0-18 mm), but the differences showed marginal significance in the supine position (p = 0.051; 3.5 ± 3.9 mm; 0-13 mm). Additionally, the differences were significantly larger for the upper (mean ± SD, 7.8 ± 5.7 mm) and middle (10.1 ± 6.5 mm) lung zones than for the lower lung zones (3.1 ± 3.3 mm) in the prone position (p = 0.011), and were larger for the upper lung zone (4.6 ± 5.0 mm) than for the middle (2.4 ± 2.0 mm) and lower (2.3 ± 2.3 mm) lung zones in the supine position (p = 0.004).ConclusionsSkin-lesion depths measured on prebiopsy supine chest CT scans were inaccurate for TNB in the prone position, particularly for nodules in the upper and middle lung zones.