Comparing an Inexpensive Handheld Ultrasound Machine and a Large Mobile Ultrasound System

Ultrasound technology is frequently used to obtain information, usually at patients bedside. The images obtained are used to guide procedure (i.e central line placement, epidural needle guidance) or to make diagnosis (i.e abnormal placentation, presence of pneumothorax). Given that the majority of this procedures and diagnosis are made at bedside, the ideal ultrasound machine should be portable, lightweight, and within an acceptable price range. Our current ultrasound machine (Sonosite - M turbo) has a price range from 15,000-20,000 dollars, not including the different probes that are needed to obtain images at different depths in the human body. Much of the cost is due to the ultrasound transducers, which have been traditionally based on piezoelectric technology. Such probes work by passing current through a piezoelectric crystal (typically quartz) that then vibrates rapidly and generates an ultrasound pulse. Creating crystal arrays is difficult and often requires hand-manufacturing. Furthermore, this technology is analog and requires downstream analog-to-digital processing hardware. Together, these characteristics increase device costs and restrict the broader dissemination of ultrasound technology.

Recently, the Butterfly iQ company created an ultrasound that is portable and at a price of slightly under two thousand dollars it allows the physician to obtain images for diagnostic and/or procedural guidance using a single probe. The company was able to significantly reduced the cost and the need for additional probes by utilizing Capacitive micro-machined ultrasound transducers (CMUTs). Essentially instead of relying on the use of specific piezoelectric crystals (current ultrasound technology), they are using a micro-chip technology to emit the vibrations that would be used to form an image. Butterfly Network has developed a CMUT imaging device that has been designed to be compliant with all applicable FDA safety regulations (see section II.C), while enabling increased portability and real-time smartphone-based image review due to the integrated circuit design. The Butterfly device was FDA-approved as of October 2017. The proposed study will compare the images acquired by the Butterfly iQ and our current Sonosite M-turbo US.

Inclusion criteria

• Patients needing a routine obstetric scan or requesting a transverse abdominis block, labor epidural or spinal for cesarean delivery.

Exclusion criteria

• Body Mass Index (BMI) > 45