title: Thoracic lymph node delineation at dose-reduced (1 mSv) dose-modulated contrast enhanced MDCT: a retrospective pilot study.
abstract: OBJECTIVE
  To compare contrast-enhanced low-dose multidetector-row computed tomography (CE-LDCT) of the chest with unenhanced (UN-) LDCT and contrast-enhanced standard-dose CT (CE-SDCT) in regard to the delineation of intrathoracic lymph nodes.
  
  
  METHODS
  Based on the international association for the study of lung cancer (IASLC) grouping of thoracic lymph nodes, two independent radiologists retrospectively assessed lymph node delineation in 9 CE-LDCTs (64 rows, 120 KV, p < 30 mAs/slice) and in 2 control groups of 36 UN-LDCTs and 36 CE-SDCTs, each matched for gender, age, chest/lung diameters, and clinical history. At a significance level of p < 0.025 (Bonferroni-correction for two control groups), two-tailed Chi-square and Fisher's exact tests were applied. For the evaluation of the inter-observer agreement, Cohen's kappa statistics were used.
  
  
  RESULTS
  CE-LDCT delineated lymph node groups significantly more often than UN-LDCT, in general (p < 0.001) and individually in the subcarinal (p < 0.025), the hilar (p < 0.001), and the peripheral lung (p < 0.001) zones. There were no significant differences in lymph node delineation between CE-LDCT and CE-SDCT. Inter-observer agreement was substantial to perfect for all lymph node zones (κ 0.64-1.0). Measurable lymph nodes did not significantly differ in size between cases and controls.
  
  
  CONCLUSIONS
  At CE-LDCT of the chest, delineation of mediastinal and hilar lymph node groups was superior to UN-LDCT and similar to CE-SDCT. CE-LDCT may be a promising alternative for patients with non-malignant lung disease, unclear chest X-ray findings, or the need for follow-up.
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilian University of Munich, Ziemssenstr. 1, 80336, Munich, Germany. marco.paolini@med.uni-muenchen.de.
authors.forename: Marco
authors.initials: M
authors.lastname: Paolini
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilian University of Munich, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Wirth
authors.affiliation: Division of Respiratory Medicine and Thoracic Oncology, Department of Internal Medicine, Ludwig Maximilian University of Munich, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: Amanda
authors.initials: A
authors.lastname: Tufman
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilian University of Munich, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Reiser
authors.affiliation: Division of Respiratory Medicine and Thoracic Oncology, Department of Internal Medicine, Ludwig Maximilian University of Munich, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: Rudolf M
authors.initials: RM
authors.lastname: Huber
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilian University of Munich, Ziemssenstr. 1, 80336, Munich, Germany.
authors.forename: Ullrich G
authors.initials: UG
authors.lastname: Mueller-Lisse
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003287:Contrast Media; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D010865:Pilot Projects; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D013902:Radiography, Thoracic / Q000379:methods*; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media
keywords: Chest CT; IASLC classification; Low dose; Lymph node delineation