title: How accurate are measurements of skin-lesion depths on prebiopsy supine chest computed tomography for transthoracic needle biopsies?
abstract: OBJECTIVE
  To evaluate the accuracy of depth measurements on supine chest computed tomography (CT) for transthoracic needle biopsy (TNB).
  
  
  METHODS
  We 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.
  
  
  RESULTS
  Skin-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 ± 6.5mm) lung zones than for the lower lung zones (3.1 ± 3.3mm) in the prone position (p=0.011), and were larger for the upper lung zone (4.6 ± 5.0mm) than for the middle (2.4 ± 2.0mm) and lower (2.3 ± 2.3mm) lung zones in the supine position (p=0.004).
  
  
  CONCLUSIONS
  Skin-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.
authors.affiliation: Department of Radiology, School of Medicine, Ewha Womans University, 911-1, Mokdong, Yancheon-gu, Seoul 158-710, Republic of Korea.
authors.forename: Joo Yeon
authors.initials: JY
authors.lastname: Cheung
authors.forename: Yookyung
authors.initials: Y
authors.lastname: Kim
authors.forename: Sung Shine
authors.initials: SS
authors.lastname: Shim
authors.forename: Jin Hwa
authors.initials: JH
authors.lastname: Lee
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Chang
authors.forename: Yon Ju
authors.initials: YJ
authors.lastname: Ryu
authors.forename: Rena J
authors.initials: RJ
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D056888:Patient Positioning / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D011300:Preoperative Care; D016684:Prone Position; D013902:Radiography, Thoracic / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000175:diagnosis*; D016683:Supine Position; D013909:Thorax / Q000473:pathology