title: Detection of bladder metabolic artifacts in (18)F-FDG PET imaging.
abstract: Positron emission tomography using (18)F-fluorodeoxyglucose ((18)F-FDG-PET) is a widely used imaging modality in oncology. It enables significant functional information to be included in analyses of anatomical data provided by other image modalities. Although PET offers high sensitivity in detecting suspected malignant metabolism, (18)F-FDG uptake is not tumor-specific and can also be fixed in surrounding healthy tissue, which may consequently be mistaken as cancerous. PET analyses may be particularly hampered in pelvic-located cancers by the bladder׳s physiological uptake potentially obliterating the tumor uptake. In this paper, we propose a novel method for detecting (18)F-FDG bladder artifacts based on a multi-feature double-step classification approach. Using two manually defined seeds (tumor and bladder), the method consists of a semi-automated double-step clustering strategy that simultaneously takes into consideration standard uptake values (SUV) on PET, Hounsfield values on computed tomography (CT), and the distance to the seeds. This method was performed on 52 PET/CT images from patients treated for locally advanced cervical cancer. Manual delineations of the bladder on CT images were used in order to evaluate bladder uptake detection capability. Tumor preservation was evaluated using a manual segmentation of the tumor, with a threshold of 42% of the maximal uptake within the tumor. Robustness was assessed by randomly selecting different initial seeds. The classification averages were 0.94±0.09 for sensitivity, 0.98±0.01 specificity, and 0.98±0.01 accuracy. These results suggest that this method is able to detect most (18)F-FDG bladder metabolism artifacts while preserving tumor uptake, and could thus be used as a pre-processing step for further non-parasitized PET analyses.
authors.affiliation: INSERM, U1099, Rennes F-35000, France; Université de Rennes 1, LTSI, Rennes F-35000, France; Keosys Medical Imaging, Saint-herblain F-44815, France. Electronic address: geoffrey.roman-jimenez@keosys.com.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Roman-Jimenez
authors.affiliation: INSERM, U1099, Rennes F-35000, France; Département de Radiothérapie, Centre Eugène Marquis, Rennes F-35000, France.
authors.forename: Renaud De
authors.initials: RD
authors.lastname: Crevoisier
authors.affiliation: Département de Radiothérapie, Centre Eugène Marquis, Rennes F-35000, France.
authors.forename: Julie
authors.initials: J
authors.lastname: Leseur
authors.affiliation: Département de Radiothérapie, Centre Eugène Marquis, Rennes F-35000, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Devillers
authors.affiliation: INSERM, U1099, Rennes F-35000, France; Université de Rennes 1, LTSI, Rennes F-35000, France.
authors.forename: Juan David
authors.initials: JD
authors.lastname: Ospina
authors.affiliation: INSERM, U1099, Rennes F-35000, France; Université de Rennes 1, LTSI, Rennes F-35000, France.
authors.forename: Antoine
authors.initials: A
authors.lastname: Simon
authors.affiliation: Keosys Medical Imaging, Saint-herblain F-44815, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Terve
authors.affiliation: INSERM, U1099, Rennes F-35000, France; Université de Rennes 1, LTSI, Rennes F-35000, France.
authors.forename: Oscar
authors.initials: O
authors.lastname: Acosta
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016208:Databases, Factual; D005260:Female; D019298:Glucose-6-Phosphate / Q000008:administration & dosage / Q000031:analogs & derivatives*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography / Q000379:methods*; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging / Q000378:metabolism
chemical_list: C047515:2-fluoro-2-deoxyglucose-6-phosphate; D019298:Glucose-6-Phosphate
keywords: Bladder artifact; Cervical cancer; Image processing; Nuclear medicine; PET/CT; Radiotherapy