title: Radiomic Analysis using Density Threshold for FDG-PET/CT-Based N-Staging in Lung Cancer Patients.
abstract: Mediastinal nodal (N)-staging done by integrated 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography/x-ray computed tomography (PET/CT) in lung cancer patients is not always accurate. In order to reduce the need for invasive staging procedures, additional surrogate parameters for the detection of malignant lymph node infiltration would be helpful. The purpose of this study was to evaluate if radiomic semi-automated density profiling in mediastinal lymph nodes can improve preclinical N-staging, irrespective of the specific lung cancer entity.
  
  
  
  This retrospective study was approved by the institutional review board. Two hundred forty-eight histologically proven lymph nodes in 122 lung cancer patients were investigated. In malignantly infiltrated lymph nodes, the specific lung cancer entity was histologically classified; benign lymph nodes were histologically classified as benign. Non-contrast enhanced [18F]FDG-PET/CT was performed before surgery/biopsy. Lymph node analyses were performed on the basis of FDG uptake and volumetric CT histogram analysis for metric lymph node sampling.
  
  
  
  Of the 248 lymph nodes, 118 were benign, 130 malignant. Malignant lymph nodes had a significantly higher median CT density (32.4 Hounsfield units (HU) (min 5.4/max 77.5 HU)) compared to benign lymph nodes (9.3 HU (min -49.5/max 60.4 HU, p < 0.05), irrespective of the histological subtype. The discrimination between different malignant tumour subtypes by means of volumetric density analysis failed. Irrespective of the malignant subtype, a possible cutoff value of 20 HU may help differentiate between benign and malignant lymph nodes.
  
  
  
  Density measurements in unclear mediastinal and hilar lymph nodes with equivocal FDG uptake in PET might serve as a possible surrogate parameter for N-staging in lung cancer patients, irrespective of the specific lung cancer subtype. This could also help to find possible high yield targets in cases where invasive lymph node staging is necessary.
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.|Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.|Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research DZL, Heidelberg, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Flechsig
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Frank
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Kratochwil
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Dusseldorf, 40225, Dusseldorf, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rath
authors.affiliation: Fraunhofer MEVIS, Institute for Medical Imaging Computing, Bremen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Moltz
authors.affiliation: Department of Nuclear Medicine and Endocrinology, Klinikum Klagenfurt, Klagenfurt, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Rieser
authors.affiliation: Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research DZL, Heidelberg, Germany.|Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Arne
authors.initials: A
authors.lastname: Warth
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.|Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research DZL, Heidelberg, Germany.
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.affiliation: Department of Radiology, Columbia University Medical Centre, New York, NY, USA.
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Schwartz
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.|Clinical Cooperation Unit, Department of Nuclear Medicine, DKFZ, Heidelberg, Germany.
authors.forename: Uwe
authors.initials: U
authors.lastname: Haberkorn
authors.affiliation: Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany. frederik@egiesel.com.|Clinical Cooperation Unit, Department of Nuclear Medicine, DKFZ, Heidelberg, Germany. frederik@egiesel.com.
authors.forename: Frederik L
authors.initials: FL
authors.lastname: Giesel
mesh_terms: D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000737:chemistry*; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D008198:Lymph Nodes / Q000000981:diagnostic imaging / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D000072078:Positron Emission Tomography Computed Tomography; D012372:ROC Curve; D011874:Radiometry
chemical_list: D019788:Fluorodeoxyglucose F18
keywords: FDG/PET-CT; Lung cancer; Radiomics; Staging