Liver Fibrosis Staging with a New 2D-Shear Wave Elastography using Comb-Push Technique

Abstract

The purpose of study was to evaluate the applicability, reproducibility, and diagnostic performance of a new 2D-shear wave elastography (SWE) using the comb-push technique (2D CP-SWE) for detection of hepatic fibrosis, using histopathology as the reference standard. This prospective study was approved by the institutional review board, and informed consent was obtained from all patients. The liver stiffness (LS) measurements were obtained from 140 patients, using the new 2D-SWE, which uses comb-push excitation to produce shear waves and a time-aligned sequential tracking method to detect shear wave signals. The applicability rate of 2D CP-SWE was estimated, and factors associated with its applicability were identified. Intraobserver reproducibility was evaluated in the 105 patients with histopathologic diagnosis, and interobserver reproducibility was assessed in 20 patients. Diagnostic performance of the 2D CP-SWE for hepatic fibrosis was evaluated by receiver operating characteristic (ROC) curve analysis. The applicability rate of 2D CP-SWE was 90.8% (109 of 120). There was a significant difference in age, presence or absence of ascites, and the distance from the transducer to the Glisson capsule between the patients with applicable LS measurements and patients with unreliable measurement or technical failure. The intraclass correlation (ICC) of interobserver agreement was 0.87, and the value for the intraobserver agreement was 0.95. The area under the ROC curve of LS values for stage F2 fibrosis or greater, stage F3 or greater, and stage F4 fibrosis was 0.874 (95% confidence interval [CI]: 0.794–0.930), 0.905 (95% CI: 0.832–0.954), and 0.894 (95% CI: 0.819–0.946), respectively. 2D CP-SWE can be employed as a reliable method for assessing hepatic fibrosis with a reasonably good diagnostic performance, and its applicability might be influenced by age, ascites, and the distance between the transducer and Glisson capsule.;목적: 조직 소견을 기준표준으로 하여, 간 섬유화 발견에 있어 comb-push technique을 이용한 새로운 2D-shear wave elastography (2D CP-SWE)의 적용 가능성, 재현성, 그리고 진단능에 대해 알아보고자 하였다. 대상 및 방법: 전향적 연구로서 140명의 환자를 대상으로 2D CP-SWE을 이용하여 간 경직도 (liver stiffness)를 측정하였다. 2D CP-SWE의 적용가능성을 평가하고, 적용가능성과 연관된 요소를 확인하였다. 조직병리학적 진단이 가능하였던 105명의 환자에서 관찰자 내 재현성을 평가하였고, 20명의 환자에서는 관찰자 간 재현성을 평가하였다. 간 섬유화 에 대한 2D CP-SWE의 진단 능력은 수신자 조작 특성 (receiver operating characteristic) 곡선 분석에 의해 평가되었다. 결과: 2D CP-SWE의 적용률은 90.8%(109/120)이었다. 간 경직도 측정이 적용 가능한 환자와 그렇지 않은 환자 사이에는 연령, 복수의 유무, 그리고 초음파 탐촉자에서 간의 피막까지의 거리가 유의미한 차이를 보였다. 관찰자간 일치도의 급내 상관관계(intraclass correlation)는 0.87이었고, 관찰자내 일치도의 급내 상관관계는 0.95였다. F2 이상의 섬유화, F3 이상의 섬유화 및 F4 섬유화에 대한 간 경직도 값의 ROC곡선 아래의 면적은 0.874 (95% 신뢰구간[CI]:0.794-0.930), 0.905 (95% CI: 0.832-0.954), 0.894 (95%CI:0.819-0.96)이었다. 결론: 2D CP-SWE는 간 섬유화를 평가함에 있어 좋은 진단능력을 보이는 신뢰성 있는 검사방법으로 사용될 수 있으며, 그 적용가능성은 환자의 연령, 복수의 유무, 및 초음파 탐촉자와 간 피막사이의 거리에 의해 영향을 받을 수 있다.