title: Sphere-enhanced microwave ablation (sMWA) versus bland microwave ablation (bMWA): technical parameters, specific CT 3D rendering and histopathology.
abstract: OBJECTIVE
  This study was designed to compare technical parameters during ablation as well as CT 3D rendering and histopathology of the ablation zone between sphere-enhanced microwave ablation (sMWA) and bland microwave ablation (bMWA).
  
  
  METHODS
  In six sheep-livers, 18 microwave ablations were performed with identical system presets (power output: 80 W, ablation time: 120 s). In three sheep, transarterial embolisation (TAE) was performed immediately before microwave ablation using spheres (diameter: 40 ± 10 μm) (sMWA). In the other three sheep, microwave ablation was performed without spheres embolisation (bMWA). Contrast-enhanced CT, sacrifice, and liver harvest followed immediately after microwave ablation. Study goals included technical parameters during ablation (resulting power output, ablation time), geometry of the ablation zone applying specific CT 3D rendering with a software prototype (short axis of the ablation zone, volume of the largest aligned ablation sphere within the ablation zone), and histopathology (hematoxylin-eosin, Masson Goldner and TUNEL).
  
  
  RESULTS
  Resulting power output/ablation times were 78.7 ± 1.0 W/120 ± 0.0 s for bMWA and 78.4 ± 1.0 W/120 ± 0.0 s for sMWA (n.s., respectively). Short axis/volume were 23.7 ± 3.7 mm/7.0 ± 2.4 cm(3) for bMWA and 29.1 ± 3.4 mm/11.5 ± 3.9 cm(3) for sMWA (P < 0.01, respectively). Histopathology confirmed the signs of coagulation necrosis as well as early and irreversible cell death for bMWA and sMWA. For sMWA, spheres were detected within, at the rim, and outside of the ablation zone without conspicuous features.
  
  
  CONCLUSIONS
  Specific CT 3D rendering identifies a larger ablation zone for sMWA compared with bMWA. The histopathological signs and the detectable amount of cell death are comparable for both groups. When comparing sMWA with bMWA, TAE has no effect on the technical parameters during ablation.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, INF 110, 69120, Heidelberg, Germany, theresa.gockner@med.uni-heidelberg.de.
authors.forename: T L
authors.initials: TL
authors.lastname: Gockner
authors.forename: S
authors.initials: S
authors.lastname: Zelzer
authors.forename: T
authors.initials: T
authors.lastname: Mokry
authors.forename: D
authors.initials: D
authors.lastname: Gnutzmann
authors.forename: N
authors.initials: N
authors.lastname: Bellemann
authors.forename: C
authors.initials: C
authors.lastname: Mogler
authors.forename: A
authors.initials: A
authors.lastname: Beierfuß
authors.forename: E
authors.initials: E
authors.lastname: Köllensperger
authors.forename: G
authors.initials: G
authors.lastname: Germann
authors.forename: B A
authors.initials: BA
authors.lastname: Radeleff
authors.forename: U
authors.initials: U
authors.lastname: Stampfl
authors.forename: H U
authors.initials: HU
authors.lastname: Kauczor
authors.forename: P L
authors.initials: PL
authors.lastname: Pereira
authors.forename: C M
authors.initials: CM
authors.lastname: Sommer
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D007089:Image Enhancement; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging* / Q000648:ultrastructure; D008872:Microwaves; D023421:Models, Animal; D012756:Sheep; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media