title: Semiautomatic algorithm for lymph node analysis corrected for partial volume effects in combined positron emission tomography-computed tomography.
abstract: Positron emission tomography-computed tomography (PET-CT) is superior compared to stand-alone PET in evaluation of malignancies. Few studies have employed high-resolution structural information to correct PET. We designed a semiautomatic algorithm using CT and PET to obtain a partial volume corrected (PVC) standardized uptake value (SUV) and a combined morphologic and functional parameter (multimodal SUV) for lymph node assessment. Lesions were segmented by a semiautomatic algorithm in CT images. Lesion volume was used for PVC and for calculating the multimodal SUV. The method was applied to 47 lymph nodes (30 patients) characterized as suspicious in 18F-fluorodeoxyglucose-PET-CT. In phantoms, PVC improved significantly the measured uptake of the lesion. In patients, 36 lymph nodes could be segmented without problems; in 11 lesions, a manual interaction was necessary. SUVs before PVC (mean 1.29) increased significantly (p < .0005) after PVC (mean 2.8). If SUV 2.5 was used as a threshold value to distinguish between benign and malignant lesions, 11 of the 47 lesions changed from benign to malignant after the PVC. The mean multimodal SUV was 0.39 mL for the benign lesions and 4.47 mL for the malignant lesions. In this work we presented a method for quantitative analysis of lymph nodes in PET-CT. PVC leads to significant differences in SUV.
authors.affiliation: Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar der Technischen Universität München, Ismaninger Strasse 22, Munich, Germany. ralph.bundschuh@tum.de
authors.forename: Ralph A
authors.initials: RA
authors.lastname: Bundschuh
authors.forename: Markus
authors.initials: M
authors.lastname: Essler
authors.forename: Julia
authors.initials: J
authors.lastname: Dinges
authors.forename: Christian
authors.initials: C
authors.lastname: Berchtenbreiter
authors.forename: Jan
authors.initials: J
authors.lastname: Mariss
authors.forename: Axel
authors.initials: A
authors.lastname: Martínez-Möller
authors.forename: Gaspar
authors.initials: G
authors.lastname: Delso
authors.forename: Melanie
authors.initials: M
authors.lastname: Hohberg
authors.forename: Stephan G
authors.initials: SG
authors.lastname: Nekolla
authors.forename: Dominik
authors.initials: D
authors.lastname: Schulz
authors.forename: Sibylle I
authors.initials: SI
authors.lastname: Ziegler
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
mesh_terms: D000465:Algorithms; D001331:Automation; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008198:Lymph Nodes / Q000000981:diagnostic imaging*; D008875:Middle Aged; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18