Steven Lee, University of Virginia Health System; Sean J. Moynihan; Matthew J. Bassignani, MD; Brandi Nicholson, MD

To ascertain the feasibility of a multiphase project, phase one was proof of the concept, whereby the ability to transmit images in near-real time was evaluated over available network infrastructures in rural areas. Phase two will assess near-term benefits extrapolated from the number of patients who avail themselves of the service who never before have had a screening mammogram, despite being of screening age.

Preliminary data on study transfer times include the following: A single, 2 MB mammogram image takes approximately 1.125 min to transfer across three bound T1 lines, regardless of distance. Study transfer times were equivalent for site #1 (28 miles from the main hospital) with an average 8 images per study, and site #2 Remote Access Medicine Mobile (RAMM) clinic in Wise, Virginia (290 miles from the main hospital) with an average 12 images per study. Thus, transfer times of 9 minutes (site #1) and 13.5 minutes (site #2) are felt to represent acceptable transfer times to allow for contemporaneous reading of mammograms with immediate recommendations made to the on-site technologist (e.g., additional magnification or compression views vs. ultrasound). Results can be conveyed to the patient and patient’s physician while the patient is still in the “mammo van.” Details of network specifics will be included in the poster.

The mobile mammography van provides a critical component in our efforts to improve patient care in underserved areas by bringing this important screening service to the patient, thus enabling the storage and distribution of the exam images for contemporaneous expert subspecialist mammography interpretation and results reporting. However, screening loses its benefit if the patient does not receive the report in a timely manner. With the remoteness of some patient populations, the convenience of the service increases the likelihood that a patient will avail themselves of screening for breast cancer. We outfitted our preexisting mobile mammography van with a smaller version of our PACS server to store and forward the exams to the main hospital for interpretation while the van remained in the field. Reporting occurred within 7 days, which is the same turn around time for screening mammography for patient’s being imaged at our main hospital.

Internet upload bandwidth is limited in rural areas, if available at all. Compressing data transmission preserves this limited resource, requiring less bandwidth and time for transmission of screenings back to the institutional PACS. The mammography unit sends studies directly to the mini PACS server on the mobile mammography van via a local network for data protection and image distribution back to the institutional PACS. Images are uploaded to the centralized storage facility of our institutional PACS via the Internet, using a proprietary 2:1 lossless compression of the data stream. Server connections to the hospital are secured with a Cisco PIX virtual private network appliance (Cisco systems, Inc., San Jose, CA). The PIX is configured to automatically obtain an IP address on its external network interface, so it can establish an IPSec tunnel back to the main hospital from any DHCP/BOOTP-enabled Internet connection.

Modalities are generally not designed for data protection or image distribution. At best, they may only be able to store images on removable media as a backup. In certain areas, Internet connectivity back to the main hospital is not available. The server has redundant components, including mirrored storage and redundant power supplies, to avoid data loss or inaccessibility from single points of failure. The server can upload images whenever Internet connectivity is available, or once the mammography van returns to the main hospital. If a radiologist were available at the screening site, the server has a network distributable client software that allows for reading of the screening mammogram locally. The client is fully featured and can display exams with the same advanced mammography viewing tools available on the main hospital’s PACS system. The client also has access to all of the patient’s historical comparison images, stored in the institutional PACS. The local client connection is tunneled through SSL and the comparisons are tunneled through the PIX IPSec tunnel. An onboard CD burning station can also create a CD copy of the screening mammogram for the patient to take to their primary physician.

Using the same available Internet connectivity, patients are registered in the hospital’s registration system wirelessly from the mammovan’s laptop, reducing the risk of losing patient information or misidentification of images. Orders are placed in the hospital’s radiology information system (RIS) (Novius, version 26.1, Siemens, Erlangen, Germany), ensuring that the study is recorded properly, that an accession number is generated for final reading, and that a report is sent to the patient and the patient’s physician. Internet access also provides online resources for researching patient history, for email, and for quick communication with the technologist should any questions arise and cellular phone access is unavailable.