Discover the EACVI Textbook of Echocardiography 2nd edition
Chapter 17 Digital echocardiography laboratory Reidar Bjørnerheim, Genevieve Derumeaux, and Andrzej Gackowski Contents Digital imaging: principles and equipment 115 Background 115 Storage format 115 Digital echo laboratory: organization and cost-effectiveness 116 Image analysis and post-processing 117 Computerized reporting of echo studies 118 Conclusion 119 References 119 Digital imaging: principles and equipment Background Modern ultrasound machines are based on digital techniques, both in image acquisition and handling, while the early machines were analogue in image processing and image output, usually to video tape. The first digital media that both stored the images without deterioration over time and enabled finding the right echo-study in acceptable time, were magneto-optical (MO) disks. They combined magnetic recording, as in digital video tape, and optical, as in rewritable computer disks (RW-CD). The reviewer could access any part of the study at any time (random access). Both the disks and the necessary machinery were relatively slow, expensive, and required a physical archive. Only when the ultrasound machines were connected with work stations in a computer network were the benefits of digital imaging fully appreciated. At first, many laboratories formed their own networks, with an on-site work station as the file server. These networks were dedicated to handling echocardiography, and many of them had no automatic backup of images, due to the large volumes of data. It soon became obvious that a remote file server was superior, especially as the cost of the hardware decreased, while server performance and bandwidth increased. From then on, the hospital IT departments had to be involved. The ordinary switched hospital computer network was sufficient, and the server could be situated anywhere . Now, information security could be in focus, since it was possible to organize automatic back-up of images, measurements, and reports. At first, back-up was based on digital tape, but currently, most back-up is based on disks in RAID (Redundant Array of Independent Disks), since such technology has plummeted in cost, the stored data are more easily accessed, and double storage allows data recovery in case of disk failure. It has become routine practice to divide the storage in a near archive, with almost instant access to the most recent recordings, and a remote archive, with delayed access. % Table 17.1 compares some storage systems. Storage format Machine vendors deliver their own proprietary formats of digital output, allowing for post-processing and analysis of their own studies in work stations and office computers with the same flexibility and quality as during the image acquisition on the echo machine. These proprietary data cannot be analysed in other vendor’s software. Also, the data volume can be huge, more than 1 GB for a comprehensive study. For routine work, there are many reasons for using a standardized protocol. Over the last two decades, the DICOM (Digital Imaging and Communications in Medicine) has become the protocol of choice for echocardiography, as it is for radiology and electrocardiography (ECG) [2,3].
SECTION 2 Cardiac morphology, haemodynamics, and physiology 18 Left ventricle: morphology and geometry 123 Peng-Fei Zhang, Yun Zhang, and Siew Yen Ho 19 Left ventricle: cardiac mechanics and left ventricular performance 126 Erwan Donal, Seisyou Kou, and Partho Sengupta 20 Left ventricle: systolic function 131 Bernard Cosyns, Thor Edvardsen, Krasimira Hristova, and Hyung-Kwan Kim 21 Left ventricle: diastolic function 147 Otto A. Smiseth, Maurizio Galderisi, and Jae K. Oh 22 Left atrium 162 Monica Rosca, Sergio Mondillo, and Kim O’Connor 23 Right ventricle and pulmonary arterial pressure 171 Annemien E. van den Bosch, Luigi P. Badano, and Julia Grapsa 24 Right atrium 185 Thierry Le Tourneau, Luis Caballero, and Tsai Wei-Chuan