Digital echocardiography 2002: now is the time

John Sutton MG, Ferrari VA, Scott CH, Wiegers SE. Failure of digital echocardiography to accurately diagnose intracardiac shunts

BACKGROUND

Intravenous agitated saline injection during transthoracic echocardiography assists in the detection of right to left intracardiac and intrapulmonary shunts. Whether digital echocardiography offers comparable sensitivity and specificity to analog tape recording to assess shunts is unknown. Technical differences between methods could lead to significant differences in shunt detection.

METHODS

Agitated saline was injected intravenously at rest and with Valsalva in 189 consecutive patient studies (406 injections). Echocardiographers assessed presence and degree of left ventricle contrast on simultaneously recorded analog tape and digital echocardiography images in blinded fashion.

RESULTS

Digital echocardiography had low overall sensitivity (rest 0.50, valsalva 0.63, late 0.39) compared to analog tape. Longer clip lengths improved sensitivity for detection of late contrast passage (rest 0.50, valsalva 0.67, late 0.46).

CONCLUSION

Digital echocardiography saline contrast studies have poor sensitivity for assessment of intracardiac shunts versus analog tape, and increasing clip length only modestly increases sensitivity. Joint Photographic Experts Group digital compression losses may be an important cause of failure to detect intracardiac shunts, including patent foramen ovale.

Clinically Compressed Digital Echocardiography: A Patient-safe Alternative to Videotape Review

Introduction: Digital storage of echocardiographic data offers logistical advantages over videotape archival. However, limited information is available on the accuracy of clinically compressed digitised examinations, an important consideration for patient safety. Materials and Methods: Transthoracic echocardiograms of 520 consecutive patients were prospectively acquired digitally and on videotape. Two echocardiologists, in consensus, reported studies in both formats sequentially. Using the videotape as a reference, the significance of any reported differences was graded from both imaging and clinical standpoints, and the reasons for these differences identified. Results: From an imaging perspective, differences between digital and videotaped studies were absent or minor in 459 cases (88%), fairly significant in 55 (11%) and very significant in 6 (1%). The main reasons for the observed differences were inadequate acquisition of optimal views (59%), an insufficient number of acquired cardiac cycles (25%) and suboptimal image quality (9%). These differences were considered to be of possible or definite clinical importance in 21 (4%) and 8 (2%) cases, respectively. In multinominal logistic regression models, the only independent predictor of significant difference between digitised and videotaped images was study complexity. Regardless of case complexity, most diagnostic errors arising from digital review were attributable to technical failure rather than observer error. Conclusions: The potential for important errors arising from exclusive reporting of clinically compressed digital echocardiograms is small. Digital echocardiography, as practiced in a routine clinical setting, offers a patient-safe alternative to videotape review. Key words: Clinical implications, Digital echocardiography, Patient safety, Videotape

Enterprise imaging and multi-departmental PACS

The aim of this review is to present the status of digital image acquisition and archiving outside of radiology and to describe the technical concepts and possibilities of how a "radiology" Picture Archiving and Communication System (PACS) can become a multi-departmental (MD-)PACS. First the principles of system integration technology are explained and illustrated by the description of a typical radiology system integration. Then four types of modality integration approaches are defined: the direct modality integration (Type-I), the integration via DICOM acquisition software (Type-II) the integration via specialised systems either with (Type-III) or without PACS connection (Type-IV). The last section is dedicated to the presentation of the PACS requirements of selected interdisciplinary modality types [Endoscopy, Ultrasound and Electrocardiography (ECG)] and clinical disciplines (Pathology, Dermatology, Ophthalmology and Cardiology), which are then compared with the technical possibilities of a MD-PACS.

A low-cost digital filing system for echocardiography data with MPEG4 compression and its application to remote diagnosis

The high cost of digital echocardiographs and the large size of data files hinder the adoption of remote diagnosis of digitized echocardiography data. We have developed a low-cost digital filing system for echocardiography data. In this system, data from a conventional analog echocardiograph are captured using a personal computer (PC) equipped with an analog-to-digital converter board. Motion picture data are promptly compressed using a moving pictures expert group (MPEG) 4 codec. The digitized data with preliminary reports obtained in a rural hospital are then sent to cardiologists at distant urban general hospitals via the internet. The cardiologists can evaluate the data using widely available movie-viewing software (Windows Media Player). The diagnostic accuracy of this double-check system was confirmed by comparison with ordinary super-VHS videotapes. We have demonstrated that digitization of echocardiography data from a conventional analog echocardiograph and MPEG 4 compression can be performed using an ordinary PC-based system, and that this system enables highly efficient digital storage and remote diagnosis at low cost.

From the echocardiography machine to the lecture room: a simple method for transferring echocardiographic frames and loops to a personal computer

The use of computers in scientific and educational presentations is rapidly increasing. As a digital presentation is ideal for showing moving images, the use of multimedia files, e.g., echocardiographic loops within these presentations, is common. Even though recent echocardiography machines store acquired data in a digital format, these data are often not readily accessible to be transferred to a personal computer. We present an easy and cost-efficient method for transferring frames and loops from any echocardiography machine into a personal computer using a digital video camera equipped with a standard analog input and flash memory. Still images and movies are stored in the camera to be subsequently transferred to a personal computer. In the computer, still images and movies are post-processed with graphical and video editing software. Finally, the still images and movies can be projected from the video camera or presented with specialized software such as PowerPoint. The images can also be used for Web-based publications and production of educational material or books on electronic media such as CD-ROM. The described method can also be used to transfer images from other proprietary devices and programs, as long as the devices are equipped with an analog video outlet.

IMPLICATIONS

The transfer of frames and loops from echocardiographic machines to personal computers is often useful for publication, teaching, and educational purposes. We present an easy and cost-effective method for transferring frames and loops from any echocardiography machine into a personal computer using a digital video camera.

Changing paradigms in dermatology: information technology

Medicine and specifically, dermatology, is undergoing enormous changes in the way in which it is practiced. Much of this is a result of a fundamental change in the manner in which information is exchanged through information technology. With the advent of more advanced telecommunications, imaging capabilities and information transfer, the very ways in which we examine patients, develop diagnoses and plan treatments as dermatologists have changed dramatically. This chapter will briefly review the development of personal computers and the Internet, as well as changes in telecommunications capabilities and how these changes have already altered how we see patients and care for them, as well as how new advances may continue to change the world of medicine and dermatology in the near future.

Comparison of diagnostic quality of motion picture experts group-2 digital video with super VHS videotape for echocardiographic imaging

BACKGROUND

Motion Picture Experts Group-2 (MPEG2) is a broadcast industry standard that allows high-level compression of echocardiographic data. Validation of MPEG2 digital images compared with super VHS videotape has not been previously reported.

METHODS

Simultaneous super VHS videotape and MPEG2 digital images were acquired. In all, 4 experienced echocardiographers completed detailed reporting forms evaluating chamber size, ventricular function, regional wall-motion abnormalities, and measures of valvular regurgitation and stenosis in a blinded fashion. Comparisons between the 2 interpretations were then performed and intraobserver concordance was calculated for the various categories.

RESULTS

A total of 80 paired comparisons were made. The overall concordance rate was 93.6% with most of the discrepancies being minor (4.1%). Concordance was 92.4% for left ventricle, 93.2% for right ventricle, 95.2% for regional wall-motion abnormalities, and 97.8% for valve stenosis. The mean grade of valvular regurgitation was similar for the 2 techniques.

CONCLUSIONS

MPEG2 digital imaging offers excellent concordance compared with super VHS videotape.