Value of ARFI Elastography for the Assessement of Ascites Syndrome

Value of ARFI Elastography for the Assessement of Ascites Syndrome, Simona Bota, Ioan Sporea, Roxana Şirli, Alina Popescu, Mirela Dănilă, Mădălina Şendroiu

ABSTRACT:
AIM: To assess the feasibility of performing acoustic radiation force impulse (ARFI) elastography in patients with ascites and its predictive value for the cirrhotic or non-cirrhotic etiology of ascites.

METHODS: Our study included 153 patients with ascites, mean age 58.8 ± 13.1 years. One hundred and fifteen (75.2%) patients had ascites in the context of cirrhosis, 29 (18.9%) had non-cirrhotic ascites (diagnosed by clinical, ultrasound, endoscopic and/or laparoscopic criteria) and in 9 (5.9%) cases we could not establish the etiology of ascites. We performed 10 ARFI measurements and the median value was calculated and expressed in meters/second (m/s). Among the 29 patients with non-cirrhotic ascites were included: 20 laparoscopically demonstrated peritoneal carcinomatosis with histological confirmation, 7 acute pancreatitis with ascites which later resolved, and one case each of lymphatic ascites and ascites in the context of a liver abscess. In 11 of the 20 patients with peritoneal carcinomatosis, the liver structure was homogenous in the ultrasound examination and in 9 patients the ultra-sound exam revealed liver metastases.

RESULTS: We could not obtain valid ARFI measurements in 5 patients (3.2%). The mean liver stiffness measurements by means of ARFI were statistically significantly higher in patients with cirrhotic ascites than in those with non-cirrhotic ascites: 3.04 ± 0.70 vs 1.45 ± 0.59 m/s (P < 0.001). For a cut-off value of 1.8 m/s for predicting cirrhosis (and ascites in the context of cirrhosis), as obtained in a previous study, ARFI had 98.1% sensitivity, 86.2% specificity, 96.4% positive predictive value, 92.5% negative predictive value and 95.6% accuracy for predicting cirrhotic ascites. For a cut-off value of 1.9 m/s the accuracy was 94.9% and for a 2 m/s cut-off value it was 92.8%.

CONCLUSION: ARFI elastography is feasible in most patients with ascites and has a very good predictive value for the cirrhotic or non-cirrhotic etiology of ascites.

© 2011 Baishideng. All rights reserved.

Key words: Ascites; Liver stiffness; Liver cirrhosis; Acoustic radiation force impulse; Elastography

COMMENTS


Background

Ascites syndrome is a quite common discovery in abdominal ultrasonography and several methods are used to establish the cause of ascites.


Innovations and breakthroughs

Acoustic radiation force impulse (ARFI) elastography is a new method, based on ultrasound, used for the evaluation of liver stiffness. The advantage of this elastographic method compared to transient elastography, is that it can be used in the presence of ascites. In our study, ARFI was determinable in 96.8% of the patients with ascites. ARFI had a very good accuracy (95.6% for a 1.8 m/s cut-off value) for the prediction of cirrhotic or non-cirrhotic etiology of the ascites.

Applications

This study supports the conclusion that in the investigation of an ascites syndrome, the first investigation that should be performed after abdominal ultrasound should be ARFI elastography.

Peer review

This is an interesting cross-sectional study evaluating liver stiffness by ARFI in subjects with ascites. The authors noticed higher values in subjects with cirrhosis, which is biological plausible. Additionally authors presented some cut-off points which could be used for the diagnosis of cirrhosis in subjects with ascites. This study is clearly presented and is well written; however, some revisions are needed to improve the manuscript.

DẤU MẮT BÒ và DẤU HÌNH BIA ĐẢO NGƯỢC ở GAN

Bull’s Eye sign hay Target sign và  Reverse Target sign ở Gan

Là các nốt đồng echo (isoechoic mass) của gan  hoặc hơi echo dày (slightly hyperechoic) hơn mô gan bình thường và được bao quanh bởi  quầng echo kém [hypoechoic rim (halo)]. Quầng dày 3-5mm tương ứng với kích thước của u, thường thấy ở di căn gan trên siêu âm B-mode.

Hình của Carol Rumack, Diagnostic Ultrasound, 2005.

Dấu hình bia đảo ngược (Reverse Target sign)

Siêu âm B-mode với các tổn thương macronodular từ isoechoic đến hyperechoic  lan toả với  hyperechoic rim (reverse target sign) trong mô gan xơ dạng nốt. G J KRAUS, P SCHEDLBAUER, S LAX, D ZEBEDIN, and F FLUECKIGER: The reverse target sign in liver disease: a potential ultrasound feature in cirrhotic liver nodules characterization. The British Journal of Radiology, 78 (2005), 355–357.

Tóm tắt: Siêu âm là phương tiện chẩn đoán hình ảnh thường dùng nhất cho bệnh nhân theo dõi bệnh lý gan. Chúng tôi báo cáo về một bệnh nhân chưa từng được chẩn đoán chai gan trước đây có các tổn thương dạng hình bia khắp mô gan; trên siêu âm, là nhiều nốt tròn đồng nhất với tâm thay đổi từ đồng echo đến echo dày với quầng echo dày bao quanh. Chúng tôi gọi là dấu hình bia đảo ngược, vì có sự đảo ngược kiểu sinh echo điển hình ở bệnh lý di căn gan. Xin gợi ý là dấu hiệu siêu âm này có thể giúp chẩn đoán phân biệt các nốt chai gan với các tổn thương gan dạng nốt khác.