The Ultrasound 2 on the International Space Station is a modified Commercial Off-The-Shelf (COTS) Ultrasound system that provides high-resolution ultrasound images of target areas in the human body. The Ultrasound unit works in conjunction with the HRF Video Power Converter which provides the capability of real-time ultrasound video downlink. The real time video allows ground personnel to remotely guide crewmembers in order to obtain the best possible images for use by investigators or medical personnel.Facility Manager(s)
Ames Research Center, Moffett Field, CA, United States
National Aeronautics and Space Administration (NASA)Expeditions Assigned
27/28,29/30,31/32Previous ISS Missions
The Ultrasound 2 is a modified Commercial Off-The-Shelf (COTS) system that includes the General Electric (GE) Medical Systems Vivid-qTM model ultrasound unit, a Video Power Converter (VPC), probes, and an ECG cable. This system replaces the original HRF Ultrasound (launched in March 2001) and includes additional features that allow for panoramic image construction to estimate muscle volume changes, speckle tracking functions to analyze cardiac stress-strain, and dynamic morphology. The Ultrasound 2 also has a decreased power consumption compared to the original unit, which permits this unit to be used on a more flexible schedule.
Ultrasound images are generated by computer and digital memory via transmission and reception of mechanical, high-frequency waves applied by a transducer. When the transducer is applied to a specific region of the body, the mechanical ultrasound waves spread through the body and produce an echo where density changes occur. The signals are transformed from high-frequency electrical signals to digital images through amplification and processing by analog and digital circuits, which filter frequency and time response options. These digital images, once saved to the memory, are displayed real-time and can be examined using different features of the unit.
The JSC team has created presets on the Ultrasound 2 for experiments such as NASA’s Integrated Cardiovascular (ICV) and Sprint, ESAs Vessel Imaging, and Space Medicine’s Ocular Scans. These presets can be further customized, if necessary, to optimize the images collected for studies, as well as facilitate crew use while aboard the International Space Station (ISS). Additionally, the ultrasound team has created the Video Power Converter (VPC), a unique full-aluminum enclosure that is outfitted with five (5) circular mil connectors, Power Switch/Breaker, Output power breaker, tether ring, USB Access panel, LED and cooling fans (5). The function of the VPC is to convert VGA video outputted from the Ultrasound 2 to balanced RS-170a (NTSC) which is then sent to the HRF Rack 1 for downlink via a connection/pass through for Ultrasound 2 Ethernet Data. The VPC also converts power from the Rack at 28V to the 20V needed by the Ultrasound 2. Hardware specifications of the VPC include resolutions up to 1280 x 1024 at 60 Hz, VGA input and output for simultaneous television/CRT viewing, and composite and S-Video outputs. It also contains an enclosed USB connection for data storage and transfer or for loading of secondary/back-up Ultrasound software onto the unit. After a scan, the data on the Ultrasound 2 is exported to the USB drive in the VPC. The data is then sent to the PC via ground commanding and subsequently downlinked for analysis.
A color-coded Overlay is installed on the Ultrasound 2 keyboard. It was designed to facilitate remote guidance during experiments. In remote guidance, a sonographer views real-time ultrasound images on the ground and directs (via privatized voice loops) the inflight crewmember-scanner on how to adjust the placement of the probe to improve the image, which keys to press in order to maximize image quality, and which images to store for later analysis. This method significantly reduces preflight crew training time and, at the same time, produces better images for experiment or medical use. Addition of the keyboard overlay allows crew members to navigate the keyboard with greater ease and efficiency, as well as ensures proper execution of procedures and prevents loss of data.
There are three probes available for use with the Ultrasound 2, curved, phased, and linear array, which are designed for particular functions on specific body parts. The curved array probe operates at a frequency of 1.8-6.0 MHz and is used for Abdominal, Renal, Fetal Heart, Urological, and Peripheral Vascular analysis. Images collected by the curved array probe can be viewed in the following modes: 2D, M-Mode, Color Flow, and Pulsed Wave Doppler. The phased array probe is used for cardiac scans. The cardiac transducer performs at a frequency of 1.5-3.6 MHz and can be used in the following modes: 2D, M-Mode, Color Flow, Continuous Wave Doppler, and Pulsed Wave Doppler. Intended uses include: Cardiological, Pediatric heart, Adult Cephalic, Abdominal, Renal, and Fetal Heart analysis. The linear array probe is used for the following applications: Peripheral Vascular, Small Organ, and Musculo-skeletal superficial analysis. It operates at a frequency of 6.0-13.0 MHz and can be viewed in the 2D, M-Mode, Color Flow, and Pulsed Wave Doppler modes. Each experiment’s probe selection is based on the function(s) and body part(s) of interest. For instance, the curved array probe is used for ESA’s Vessel Imaging experiment, while the phased array probe is used for NASA’s ICV, and the linear array probe for NASA’s Sprint experiment. Additionally, a three-lead ECG cable is also available to provide an ECG signal in conjunction with echo images when desired. NASA’s Integrated Cardiovascular and ESA’s Vessel Imaging experiment both utilize this capability.
The Ultrasound 2 can also be used for medical emergencies and for periodic assessments of crew health. Currently, ocular scans are conducted once a month or as requested by Space Medicine and utilize the 12L-RS probe.
The Ultrasound 2 unit and components were flown on STS-135/Flight ULF7 and its first use was on 23 August 2011 for an Integrated Cardiovascular cardiac echo scan.
The Ultrasound 2 is used in a variety of experiments in order to monitor the physiological changes that result from exposure to microgravity. It is also used to monitor the health of the crew and can be used in the event of a medical contingency. The Ultrasound 2 is connected to the HRF Rack 1, powered on, and peripherals are attached based on the requirements for the planned activity. Remote guidance of the scan is enabled by real-time downlink of scanhead video and direct, privatized voice communication between the crew and a sonographer. After the scan is complete, data is copied from the Ultrasound 2 to the USB in the VPC and then from the USB to the HRF PC. The data is then downlinked for analysis. At the end of the activity, the Ultrasound 2 is powered off, disconnected from the HRF Rack and stowed until the next use.