title: Incorporation of preprocedural PET into CT-guided radiofrequency ablation of hepatic metastases: a nonrigid image registration validation study.
abstract: This study evaluates the accuracy of augmenting initial intraprocedural computed tomography (CT) during radiofrequency ablation (RFA) of hepatic metastases with preprocedural positron emission tomography (PET) through a hardware-accelerated implementation of an automatic nonrigid PET-CT registration algorithm. The feasibility of augmenting intraprocedural CT with preprocedural PET to improve localization of CT-invisible but PET-positive tumors with images from actual RFA was explored. Preprocedural PET and intraprocedural CT images from 18 cases of hepatic RFA were included. All PET images in the study originated from a hybrid PET/CT scanner, and PET-CT registration was performed in two ways: (1) direct registration of preprocedural PET with intraprocedural CT and (2) indirect registration of preprocedural CT (i.e., the CT of hybrid PET/CT scan) with intraprocedural CT. A hardware-accelerated registration took approximately 2 min. Calculated registration errors were 7.0 and 8.4 mm for the direct and indirect methods, respectively. Overall, the direct registration was found to be statistically not distinct from that performed by a group of clinical experts. The accuracy, execution speed, and compactness of our implementation of nonrigid image registration suggest that existing PET can be overlaid on intraprocedural CT, promising a novel, technically feasible, and clinically viable approach for PET augmentation of CT guidance of RFA.
authors.affiliation: Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, 22 S. Greene St., Baltimore, MD 21201, USA.
authors.forename: Peng
authors.initials: P
authors.lastname: Lei
authors.forename: Omkar
authors.initials: O
authors.lastname: Dandekar
authors.forename: David
authors.initials: D
authors.lastname: Widlus
authors.forename: Raj
authors.initials: R
authors.lastname: Shekhar
mesh_terms: D000465:Algorithms; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods*