Washington UniversitySchool of Medicine
Electronic Radiology Laboratory Electronic Radiology Lab banner

Silent Infarct Transfusion (SIT) Study


Sickle Cell Disease Background

Sickle cell disease is an inherited blood disorder in which red blood cells contain an abnormal form of hemoglobin, the protein in red blood cells that carries oxygen throughout the body. This abnormality leads to anemia. Red blood cells become misshapen so that they look like "sickles" under the microscope. These sickle-shaped cells can clog the blood stream and cause obstructions resulting in serious medial problems. Sickle cell disease is the most common genetic disorder in African-Americans. The disease affects one in 400 African-American infants — and 22 percent of these children will suffer a silent stroke before they finish high school. Identifying silent strokes are important because preliminary research at Washington University over the past decade reveals that silent strokes seriously affect children’s educational attainment and they remain at increased risk for further neurologic injury.

SIT Project Description

The Silent Infarct Transfusion (SIT) Study is an international, multi-center clinical study aimed at evaluating the effectiveness of blood transfusion therapy for silent strokes, a common and serious complication of sickle cell disease.  The six-year study involves 25 sites in the United States, Canada, England and France. The trial is funded by an $18.5 million National Institutes of Health grant, awarded to Washington University School of Medicine in Saint Louis, serving as the coordinating center with Michael DeBaun, Associate Professor of Pediatrics, Biostatistics and Neurology.


The study’s goal is to determine the efficacy of blood transfusion therapy as a treatment for preventing silent strokes. Silent strokes — strokes that do not cause immediately obvious symptoms — frequently go unrecognized and are one of the most serious afflictions associated with sickle cell disease. They can cause declines in school performance, increased forgetfulness and a diminished ability to follow even simple instructions.

The Role of ERL

The Electronic Radiology Laboratory serves as the Imaging Core for the SIT Study and is responsible for managing the electronic image processing system that obtains the MRI studies on the children enrolled in the study and presents the images to a panel of radiologists for interpretation.  ERL created a software package known as the Clinical Studies Workstation (CSW). This software, normally installed on a laptop computer, is used to acquire images via the Digital Imaging and Communications in Medicine (DICOM) communication protocol.  The images are then de-identified and study specific identifiers added.  The laptop may be physically transported to another location to be connected to the Internet. The CSW package includes firewall software and virtual private network (VPN) client software.  A site coordinator initiates a VPN connection to the secure network at ERL, the VPN software encrypts all traffic between the workstation and ERL, and the workstation transmits images via DICOM over the encrypted channel. Patient identity is protected by both de-identification software and encrypted transmission.

After a study is received ERL personnel perform quality assurance (QA) steps to check for compliance with the study imaging protocol and to make sure the entire PHI has been removed.  If the study passes QA it is uploaded to the image viewing system.  The check-in process also creates a web based work list for the radiologists who use a VPN connection over the Internet to view the studies on a PC with dual, image-quality monitors.

A web based reporting process provides the radiologist with a series of different Case Report Forms (CRFs).  Each CRF is designed to collect the appropriate information for the type of MRI being read.  In addition to collecting the findings from the individual radiologist, ERL also supports a web based consensus reporting process whereby the radiology panel provides a consensus reading.  Data collected during check-in and readings from the individual radiologists and consensus reports are stored in a database.