Recording Echocardiograms

Recording Echocardiograms

• The development of instruments for creating images and gathering physiologic information of the heart has been accompanied by a parallel history of developing techniques for recording this information.
• Helmut Hertz focused on recording rather than creating ultrasonic images, leading to the development of ink-jet technology.
• Early echocardiography (early 1960s) primarily used Polaroid cameras for recording A-mode and M-mode echocardiograms.
• This method was limited and problematic.
• Some researchers, like Gramiak, used 35-mm film to record M-mode echocardiograms.
• Early efforts focused on getting commercial companies to provide strip chart recorders for M-mode echocardiograms.
• Real-time two-dimensional images required new recording schemes.
• Initially, super 8 movie film was used, achieved by directing a movie camera at the oscilloscope.
• This was quickly replaced by videotape.
• Reel-to-reel tape recorders were used first, followed by cassette recorders.
• Sanyo produced a popular tape recorder in the early years.
• Analyzing studies frame by frame was difficult, requiring the use of a small button-like control, with no backward viewing.
• Panasonic developed a tape recorder allowing forward and backward viewing as well as frame-by-frame analysis.
• Videotape became the standard for recording echocardiograms due to the prevalence of two-dimensional echocardiography.
• Videotape also has limitations:
  • Problematic for serial studies.
  • Inconvenient accessibility.
  • Measurements could not be made from videotaped images.
  • Copies of videotaped images were degraded.
• Digital recording of echocardiograms began in the early 1980s, with increasing interest since then.
• Digital recording has numerous advantages:
  • Facilitated side-by-side comparisons.
  • Easy to make measurements.
  • More accessible images.
• Initially, digital images were generated by grabbing the video signal (from the instrument or by digitizing the videotape).
• Direct digital output from ultrasonic instruments has become available in recent years.
• DICOM (Digital Imaging and Communication in Medicine) standards have facilitated the use of digital imaging, enhancing its utility.