Acoustic Liver Biopsy in Patients with Hepatitis C and Advanced Liver Fibrosis Using Endoscopic Ultrasound

Introduction Patients with Hepatitis C and Advanced Liver Fibrosis Using Endoscopic Ultrasound Transabdominal ultrasound (TUS) is commonly used to evaluate the liver. It is excellent for the assessment of the blood vessels, to determine ductal dilatation, and as a screening lest for hepatocellular carcinoma in cirrhosis. Even though TUS can be used lo evaluate liver parenchyma, it bas certain limitations. TUS of the liver varies from person to person because the acoustic waves have lo traverse the abdominal wall before entering the liver and when returning to the transducer. The composition of Ibe abdominal wall is highly variable between individuals. The acoustic waves are attenuated by abdominal wall fal and muscle layers. To compensate for the for the differences between individuals The sonografer must adjust the range, gain, contrast, frequency, and slope time gain (.STG) on the ultrasound processor. Since these setting differ from individual to individual, it is possible to standardize these parameters to compare individuals using TUS.

In a prior sludy we demonstrated that ultrasound imaging through the gastric wall using endoscopic ultrasound (EUS) allows the ultrasound transducer id be placed at a constant distance from the liver Because of this it was possible to keep the sellings on the ultrasound processor constant so that the entire procedure can be standardised and images from one subject can be compared to images from another subject. Using EUS For previous data suggest thin we can differentiate between patients with cirrhosis, steatosis and normal controls.

Aim

The aim of ihis study was to use EUS to determine the severity of Fibrosis in patients with advanted liver fibrosis due to chronic hepatitis. C infection. This was based on the hypothesis that the amount or fibrous in the liver, in different grades of cirrhosis, will produce different degrees of luminosity on endoltmiinal ultrasound images after standardizing ihe ultrasound parameters.

Methods

Seven patients wilh hepatitis C and advanced liver fibrosis, Ishak ymdes 4-6, were evaluated . All patient give informed consent which was approved by the institutional review board for participation in the study. The study was registered with the clinical trials registry under the number.

The histological specimens of the liver were read by a pathologist and were scored based on Ishak staging (Ishak score 4 is defined as

marked bridging, Ishak score 5 is defined as marked bridging with occasional nodules: and. Ishak score 6 is defined as extensive scarring and cirrhosis, All subjects had well compensated liver disease.

Dala was collected using an Aloka ultrasound processor (SSD-5000. Aloka Co., Ltd, Tokyo, Japan) and an Olympus radial echo endoscope (GF-UCWP-ALS. Olympus America Inc.. Melville, New York. USA). Before ihe start of the procedure the settings on die Aloka. processor were kepi constant for all subjects (range 6, gain &2. contrast S, Irequency 16 H?.. STC 50%).

All patients underwent conscious sedation using midazolam and fenlanyl. An Olympus radial echo endoscope was passed into the stomach to an area just below the gastroesophageal junction to image the left lobe of the liver. The EUS transducer was placed againt the wall of the stomach to maintain a constant distance from the liver.

The balloon around (he EUS transducer was inflated with a minimum amount of water to achieve acouslk coupling.

The ultrasound procedure was recorded on super VHS videotape.

Evaluation of Standardised Endoluminal Ultrasound Images Images were digitized from the recorded ultrasound videotape using Image Pro Plus software (version 4,U Media Cybernetics, Maryland, USA). Five images of ihe liver were chosen per patieni based on the quality of the digitized images. Image analysis was performed using Photoshop by two independent investigators blinded lo ihe Ishak fibrosis store uf the patient and Ihe readings of the other investigator. The two independent investigators performed the image analysis on the same images in the same palients hut were given ihe freedom to choose the area of interest and to eliminate (he major blood vessels, major bile duels and artifacts, and do the measurements independently of eachh other.