(1)
Department of Radiology Chair, Central State Medical Academy Department of Radiology, Moscow, Russia
The concept of automated breast US dates back to the 1970s when the first usable systems were reported by Maturo et al. [1]. All automatic US breast scanners have been classified as prone-type or supine-type scanners [2]. The first method used a special water bath-type scanning, the second carried out water-coupled scanning. Old generation automated scanners were of inferior quality with relatively low-frequency transducers of 4–7 MHz [3].
Interest in obtaining three-dimensional images of the breast has increased since the early 1990s after the development of powerful computer programs. Currently 3D imaging is a daily routine all over the world.
At the moment the possibility of computer-aided breast studies is provided by several US diagnostic systems, most of which unfortunately are not certified in the Russian market, although actively and widely used throughout the world, having Food and Drug Administration (FDA) approval. Comparative characteristics of these diagnostic systems are summarized in Table 1.1.
Table 1.1
Comparison of US devices for automatic breast scanning
Type of device | SonoCine (hybrid) | Invenia ABUS (GE), ACUSON S2000 ABVS (Siemens) | Combined US system (Ultrasonix) |
---|---|---|---|
Scanning type | Conventional US sensor mounted on a handle | Large transducer with a special compression paddle | Concave sensor built into a couch, rotating 360° |
Patient position during the study | Supine | Supine | Prone |
With which radiological technique it could be integrated | N/A | Possible with MMG at compatible scans | CT, MRI |
Acquisition time | 15–30 min | 15–20 min | 2–4 min |
FDA approval | 2008 | 2012 | Clinical evaluation |
The first hybrid system included a 2D high-resolution sensor, mounted on a special stand to perform automatic scans [4]. This device was not equipped with a special wide aperture transducer, and scanning was performed mechanically, by moving the conventional transducer over the breast, in a way similar to that used for handheld ultrasound (HHUS). A special silicone pad was applied to facilitate sliding on the breast. This system was approved by the FDA in 2008 for clinical use in the USA [5]. The robotic device could convert from 2000 to 5000 2D axial scans into a 3D image. The first fundamental scientific works and mass screenings using automatic 3D scans were performed on this hybrid system. Several studies using such an ABUS system have been published, showing no improvement in detection of breast cancer in screening programs [6–8]. The disadvantages of the method included the impossibility of subsequent reconstructions of 3D images obtained and the inability to restore the initially collected 2D data from the combined array. The image was analyzed in real time, similar to any standard US examination.