Chronological changes of radiofrequency ablation zone in rabbit liver: an in vivo correlation between gross pathology and histopathology

Abstract

Objective: To examine the gross pathology and histopathology of ablation zones created from radiofrequency (RF) ablation and to correlate their chronological changes. Methods: A total of 48 in vivo ablation zones (16 rabbit livers) were obtained immediately after and also 30 min, 1 h and 2 h after RF ablation and were subjected to haematoxylin and eosin (H&E) staining, nicotinamide adenine dinucleotide (NADH) diaphorase staining, terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining. Chronological changes in gross pathology and histopathology were evaluated and correlated with each other. Results: Peripheral red zones on gross pathology correlated with peripheral zones on H&E staining, lightly stained peripheral zones on NADH staining and peripheral positive zones on TUNEL staining. Central white zones on gross pathology correlated with combined central and border zones on H&E staining, central negative zones on NADH staining and combined central-positive and middle-negative zones on TUNEL staining. Boundary visibility between central white and peripheral red zones on gross pathology was significantly higher at 1 and 2 h than immediately after RF ablation. As time increased after RF ablation, visibility of the border zone on H&E staining and the grade of positively stained hepatocytes in the peripheral zone on TUNEL staining increased. Conclusion: Chronological changes in gross pathology of RF ablation zones correlated well with histopathology. The boundary between the central white and peripheral red zones tended to become clear at 1 h after RF ablation. Advances in knowledge: (1) RF ablation zones show chronological changes on gross pathology and histopathology. (2) Gross pathology and histopathology correlate well with each other.

Comparison of ablation performance between dual internally cooled wet tip and conventional dual internally cooled tip radiofrequency electrodes: an experimental study in ex vivo bovine liver

“…Third, a histologic analysis was not performed to evaluate cell necrosis. However, previous studies have demonstrated that central white zone corresponds with total necrosis, whereas peripheral red zone is a mixture of dying and dead cells [13]. Considering that the peripheral red zone was thin in our study, this would not significantly affect our results.…”

“…The ablation volume was also significantly larger with ICWT than that with ICT (p ¼ .003) due to the differences in ablation zone diameters. The thickness of the peripheral red zones, comprising a mixture of damaged and dead cells rather than totally dead cells [13], was small in both electrodes, indicating that the rather short 6-min ablation time was sufficient in creating a 3-cm ablation zone. The amount of applied energy was also bigger with ICWT than that with ICT (p ¼ .003), which would correspond with the larger ablation volume since the amount of applied energy is reported to correspond to the volume of the abla-tion zone [21] and thus would be more time-energy efficient [22].…”

“…Only the study coordinator was aware of the type of electrodes used for the ablation of each photograph, whereas the two observers were blinded to this information. They independently measured the three diameters, distances between each electrode and the closest outer margin of the ablation zone along the x-axis (DEM), circularity of the ablation zone on the second cut surface (zx plane), and thickness of peripheral red zones (Figure 3) [13]. They also recorded whether an unexpected vessel was present near the ablation zone margin that could affect its shape.…”

Characterization of the ablation zones produced by three commercially available systems from a single vendor for radiofrequency thermoablation in an ex vivo swine liver model

“…Moreover, we estimated ablation volumes by analysing macroscopic photographs taken only from a single slice. While evidence exists in support of the use of gross pathological examination as a reliable indicator of lethally damaged tissue in RFA (Gemeinhardt et al, 2016;Song et al, 2017), a real 3D ablation analysis (either performed by multi slice histology, macroscopy or CT) might have improved the accuracy of our results and should be preferred for the assessment of in vivo ablated zones.…”

Ablative Outcomes of Various Energy Modes for No-Touch and Peripheral Tumor-Puncturing Radiofrequency Ablation: An Ex Vivo Simulation Study

“…The white zone proportion of AMm at a 25-mm interelectrode distance was the lowest in the DSM mode, although the ablative margin with DSM was the largest when compared with that in the other energy modes. A previous study demonstrated that the central white zone corresponded to total necrosis, whereas the peripheral red zone was a mixture of dying and dead cells [ 14 ]. Although it is unknown which of the two zones (white zone only or white + red zone) should be considered in the evaluation of the true ablation zone, a larger white zone would be preferable to ensure complete tumor necrosis.…”