title: Computed Tomography Perfusion, Magnetic Resonance Imaging, and Histopathological Findings After Laparoscopic Renal Cryoablation: An In Vivo Pig Model.
abstract: The present study investigates how computed tomography perfusion scans and magnetic resonance imaging correlates with the histopathological alterations in renal tissue after cryoablation. A total of 15 pigs were subjected to laparoscopic-assisted cryoablation on both kidneys. After intervention, each animal was randomized to a postoperative follow-up period of 1, 2, or 4 weeks, after which computed tomography perfusion and magnetic resonance imaging scans were performed. Immediately after imaging, open bilateral nephrectomy was performed allowing for histopathological examination of the cryolesions. On computed tomography perfusion and magnetic resonance imaging examinations, rim enhancement was observed in the transition zone of the cryolesion 1week after laparoscopic-assisted cryoablation. This rim enhancement was found to subside after 2 and 4 weeks of follow-up, which was consistent with the microscopic examinations revealing of fibrotic scar tissue formation in the peripheral zone of the cryolesion. On T2 magnetic resonance imaging sequences, a thin hypointense rim surrounded the cryolesion, separating it from the adjacent renal parenchyma. Microscopic examinations revealed hemorrhage and later hemosiderin located in the peripheral zone. No nodular or diffuse contrast enhancement was found in the central zone of the cryolesions at any follow-up stage on neither computed tomography perfusion nor magnetic resonance imaging. On microscopic examinations, the central zone was found to consist of coagulative necrosis 1 week after laparoscopic-assisted cryoablation, which was partially replaced by fibrotic scar tissue 4 weeks following laparoscopic-assisted cryoablation. Both computed tomography perfusion and magnetic resonance imaging found the renal collecting system to be involved at all 3 stages of follow-up, but on microscopic examination, the urothelium was found to be intact in all cases. In conclusion, cryoablation effectively destroyed renal parenchyma, leaving the urothelium intact. Both computed tomography perfusion and magnetic resonance imaging reflect the microscopic findings but with some differences, especially regarding the peripheral zone. Magnetic resonance imaging seems an attractive modality for early postoperative follow-up.
authors.affiliation: 1 Department of Urology, Aarhus University Hospital, Denmark.
authors.forename: Tommy Kjærgaard
authors.initials: TK
authors.lastname: Nielsen
authors.affiliation: 1 Department of Urology, Aarhus University Hospital, Denmark.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Østraat
authors.affiliation: 2 Department of Radiology, Aarhus University Hospital, Denmark.
authors.forename: Ole
authors.initials: O
authors.lastname: Graumann
authors.affiliation: 3 MRI Center, Aarhus University Hospital, Denmark.
authors.forename: Bodil Ginnerup
authors.initials: BG
authors.lastname: Pedersen
authors.affiliation: 2 Department of Radiology, Aarhus University Hospital, Denmark.
authors.forename: Gratien
authors.initials: G
authors.lastname: Andersen
authors.affiliation: 4 Department of Pathology, Aarhus University Hospital, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Høyer
authors.affiliation: 1 Department of Urology, Aarhus University Hospital, Denmark.
authors.forename: Michael
authors.initials: M
authors.lastname: Borre
mesh_terms: D000818:Animals; D003452:Cryosurgery; D005260:Female; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D009392:Nephrectomy / Q000379:methods; D034421:Sus scrofa; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: CT-perfusion; MRI scan; animal; computed tomography; cryo surgery; cryoablation; kidney cancer; pathology