OBJECTIVE: Pseudoenhancement of an avascular region on contrast-enhanced ultrasound often occurs within an echogenic region of a radiofrequency ablation zone due to nonlinear ultrasound propagation through intervening microbubble-perfused tissue. The purpose of this study was to describe the imaging features of this artifact. MATERIALS AND METHODS: Twenty-six patients with no tumor recurrence within ablation zones were included. Two radiologists assessed contrast-enhanced ultrasound pseudoenhancement in the arterial (< 30 seconds), portal (30-90 seconds), and late (> 90 seconds) phases. If pseudoenhancement was present, the following information was recorded: the degree, time to first appearance, progression over time, and location. The corresponding gray-scale echogenicity (hypo-, iso-, or hyperechoic) and lesion depth were also noted. RESULTS: Fourteen lesions (14/26, 54%) showed pseudoenhancement on contrast-enhanced ultrasound. Fourteen (100%) corresponded to the hyperechoic area within the ablation zone on gray-scale ultrasound and were nonmarginal in location. Pseudoenhancement occurred more frequently in deep lesions (> or = 5 cm) than in superficial lesions (< 5 cm) (p = 0.002). Pseudoenhancement was initiated most frequently in the portal phase (9/14, 64%), followed by the arterial phase (4/14, 29%) and late phase (1/14, 7%). Progression in the degree of pseudoenhancement was shown in most cases (12/14, 86%) and no washout was seen. CONCLUSION: Pseudoenhancement is frequently seen within ablation zones on contrast-enhanced ultrasound, particularly in deep echogenic lesions. However, pseudoenhancement follows enhancement of the parenchyma between the transducer and target. This observation is consistent with nonlinear propagation of the ultrasound beam, which increases with bubble concentration. Pseudoenhancement shows relatively late initiation, progression over time, and nonmarginal location; these findings are different from those seen in typical tumor recurrence, which shows early enhancement and washout at the margin of the ablation zone.
OBJECTIVE: Pseudoenhancement of an avascular region on contrast-enhanced ultrasound often occurs within an echogenic region of a radiofrequency ablation zone due to nonlinear ultrasound propagation through intervening microbubble-perfused tissue. The purpose of this study was to describe the imaging features of this artifact. MATERIALS AND METHODS: Twenty-six patients with no tumor recurrence within ablation zones were included. Two radiologists assessed contrast-enhanced ultrasound pseudoenhancement in the arterial (< 30 seconds), portal (30-90 seconds), and late (> 90 seconds) phases. If pseudoenhancement was present, the following information was recorded: the degree, time to first appearance, progression over time, and location. The corresponding gray-scale echogenicity (hypo-, iso-, or hyperechoic) and lesion depth were also noted. RESULTS: Fourteen lesions (14/26, 54%) showed pseudoenhancement on contrast-enhanced ultrasound. Fourteen (100%) corresponded to the hyperechoic area within the ablation zone on gray-scale ultrasound and were nonmarginal in location. Pseudoenhancement occurred more frequently in deep lesions (> or = 5 cm) than in superficial lesions (< 5 cm) (p = 0.002). Pseudoenhancement was initiated most frequently in the portal phase (9/14, 64%), followed by the arterial phase (4/14, 29%) and late phase (1/14, 7%). Progression in the degree of pseudoenhancement was shown in most cases (12/14, 86%) and no washout was seen. CONCLUSION: Pseudoenhancement is frequently seen within ablation zones on contrast-enhanced ultrasound, particularly in deep echogenic lesions. However, pseudoenhancement follows enhancement of the parenchyma between the transducer and target. This observation is consistent with nonlinear propagation of the ultrasound beam, which increases with bubble concentration. Pseudoenhancement shows relatively late initiation, progression over time, and nonmarginal location; these findings are different from those seen in typical tumor recurrence, which shows early enhancement and washout at the margin of the ablation zone.
Authors: M-X Tang; H Mulvana; T Gauthier; A K P Lim; D O Cosgrove; R J Eckersley; E Stride Journal: Interface Focus Date: 2011-05-18 Impact factor: 3.906
Authors: Brooks D Lindsey; Jinwook Kim; Paul A Dayton; Xiaoning Jiang Journal: IEEE Trans Ultrason Ferroelectr Freq Control Date: 2017-05-08 Impact factor: 2.725
Authors: Andrej Lyshchik; Yuko Kono; Christoph F Dietrich; Hyun-Jung Jang; Tae Kyoung Kim; Fabio Piscaglia; Alexander Vezeridis; Juergen K Willmann; Stephanie R Wilson Journal: Abdom Radiol (NY) Date: 2018-04
Authors: Christoph F Dietrich; Michalakis Averkiou; Michael Bachmann Nielsen; Richard G Barr; Peter N Burns; Fabrizio Calliada; Vito Cantisani; Byung Choi; Maria C Chammas; Dirk-André Clevert; Michel Claudon; Jean-Michel Correas; Xin-Wu Cui; David Cosgrove; Mirko D'Onofrio; Yi Dong; JohnR Eisenbrey; Teresa Fontanilla; Odd Helge Gilja; Andre Ignee; Christian Jenssen; Yuko Kono; Masatoshi Kudo; Nathalie Lassau; Andrej Lyshchik; Maria Franca Meloni; Fuminori Moriyasu; Christian Nolsøe; Fabio Piscaglia; Maija Radzina; Adrian Saftoiu; Paul S Sidhu; Ioan Sporea; Dagmar Schreiber-Dietrich; Claude B Sirlin; Maria Stanczak; Hans-Peter Weskott; Stephanie R Wilson; Juergen Karl Willmann; Tae Kyoung Kim; Hyun-Jung Jang; Alexandar Vezeridis; Sue Westerway Journal: Ultrasound Int Open Date: 2018-02-07