Person:
Ryou, Marvin

Profile Picture

Email Address

AA Acceptance Date

Birth Date

Research Projects

Organizational Units

Job Title

Last Name

Ryou

First Name

Marvin

Name

Ryou, Marvin
Author's Publications: search.filters.isAuthorOfPublication.a0f4ea5d-e4e1-4e04-87b2-364717df51bb

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Publication
    A Prospective Blinded Study of Endoscopic Ultrasound Elastography in Liver Disease: Towards a Virtual Biopsy
    (Korean Society of Gastrointestinal Endoscopy, 2018) Schulman, Allison R.; Lin, Ming V.; Rutherford, Anna; Chan, Walter; Ryou, Marvin
    Background/Aims Liver biopsy has traditionally been used for determining the degree of fibrosis, however there are several limitations. Endoscopic ultrasound (EUS) real-time elastography (RTE) is a novel technology that uses image enhancement to display differences in tissue compressibility. We sought to assess whether liver fibrosis index (LFI) can distinguish normal, fatty, and cirrhotic liver tissue. Methods: A total of 50 patients undergoing EUS were prospectively enrolled. RTE of the liver was performed to synthesize the LFI in each patient. Univariate and multivariable analyses were performed. Chi-square and t-tests were performed for categorical and continuous variables, respectively. A p-value of <0.05 was considered significant. Results: Abdominal imaging prior to endoscopic evaluation suggested normal tissue, fatty liver, and cirrhosis in 26, 16, and 8 patients, respectively. Patients with cirrhosis had significantly increased mean LFI compared to the fatty liver (3.2 vs. 1.7, p<0.001) and normal (3.2 vs. 0.8, p<0.001) groups. The fatty liver group showed significantly increased LFI compared to the normal group (3.8 vs. 1.4, p<0.001). Multivariable regression analysis suggested that LFI was an independent predictor of group features (p<0.001). Conclusions: LFI computed from RTE images significantly correlates with abdominal imaging and can distinguish normal, fatty, and cirrhotic-appearing livers; therefore, LFI may play an important role in patients with chronic liver disease.
  • Thumbnail Image
    Publication
    An implantable wireless biosensor for the immediate detection of upper GI bleeding: a new fluorescein-based tool for diagnosis and surveillance (with video)
    (Elsevier BV, 2011) Ryou, Marvin; Nemiroski, Alex; Azagury, Dan; Shaikh, Sohail N.; Ryan, Michele B.; Westervelt, Robert; Thompson, Christopher C.
    Background: Early recurrent hemorrhage after endoscopic intervention for acute upper GI bleeding (UGIB) can approach 20% and leads to increased morbidity and mortality. Little has changed over the past several decades regarding immediate posthemorrhage surveillance, and there has likewise been no significant improvement in outcomes. Objective: To develop and test an endoscopically implantable wireless biosensor for real-time detection of fluorescein-labeled blood in ex vivo and in vivo porcine models of UGIB. Setting: Animal laboratory. Design: Benchtop and acute animal studies. Subjects: Five pigs. Interventions: UGIB models were surgically created in living pigs. Biosensors were endoscopically deployed in the stomach using standard endoscopic clips. The ability to detect acute UGIB and estimated blood loss leading to biosensor activation were recorded. Feasibility of wireless data transmission out of the body to an external computer and cell phone was assessed. Main Outcome Measurements: Technical feasibility and immediate complications. Results: A porcine UGIB model was successfully created. Biosensors were able to detect all acute bleeding events and wirelessly transmit out of the body, and successfully sent an emergency text message to the intended cell phone in all cases. Average estimated blood loss leading to biosensor activation was 30 mL (10 –75 mL). Limitations: Animal study; small numbers. Conclusions: An endoscopically implantable wireless biosensor successfully detected acute hemorrhage in a porcine UGIB model and sent an emergency cell-phone alert in real time.