Teleradiology : An Introduction
- Ganesh Bdr. Thapa BScMIT 3rd Batch
- Deelip Saud BScMIT 5th Batch
I. INTRODUCTION AND DEFINITION
Teleradiology is the electronic transmission of radiologic images from one location to another for the purposes of interpretation and/or consultation. Teleradiology may allow more timely interpretation of radiologic images and give greater access to secondary consultations and to improved continuing education. Users in different locations may simultaneously view images. Appropriately utilized, teleradiology may improve access to radiologic interpretations and thus significantly improve patient care. Teleradiology is not appropriate if the available teleradiology system does not provide images of sufficient quality to perform the indicated task. When a teleradiology system is used to render the official interpretation, there should not be a clinically significant loss of data from image acquisition through transmission to final image display. For transmission of images for display use only, the image quality should be sufficient to satisfy the needs of the clinical circumstance. This standard defines goals, qualifications of personnel, equipment guidelines, licensing, credentialing, liability, communication, quality control, and quality improvement for teleradiology. While not all-inclusive, the standard should serve as a model for all physicians and health care workers who utilize teleradiology.
II. GOALS
Teleradiology is an evolving technology. New goals will continue to emerge. The current goals of teleradiology include:
A. Providing consultative and interpretative radiologic services.
B. Making radiologic consultations available in medical facilities without on-site radiologic support.
C. Providing timely availability of radiologic images and image interpretation in emergent and nonemergent clinical care areas.
D. Facilitating radiologic interpretations in on-call situations.
E. Providing subspecialty radiologic support as needed.
F. Enhancing educational opportunities for practicing radiologists.
G. Promoting efficiency and quality improvement.
H. Providing interpreted images to referring providers.
I. Supporting telemedicine.
J. Providing supervision of off-site imaging studies.
III. QUALIFICATIONS OF PERSONNEL
The radiologic examination at the transmitting site must be performed by qualified personnel trained in the examination to be performed. In all cases this means a licensed and/or registered radiologic technologist, radiation therapist, nuclear medicine technologist, or sonographer. This technologist must be under the supervision of a qualified licensed physician. It is desirable to have a Qualified Medical Physicist and/or image management specialist on site or as consultants.
A. Physician
The official interpretation of images must be done by a physician.
B. Radiologic Technologist, Radiation Therapist, Nuclear Medicine Technologist, or Sonographer
The technologist, therapist, or sonographer should be:
1. Certified by the appropriate registry
2. Trained to properly operate and supervise the teleradiology system.
C. Qualified Medical Physicist
D. Image Management Specialist
IV. EQUIPMENT SPECIFICATIONS
Specifications for equipment used in teleradiology will vary depending on the individual facility’s needs but in all cases should provide image quality and availability appropriate to the clinical need. Digital Imaging and Communication in Medicine (DICOM) Standard is strongly recommended for all new equipment acquisitions, and consideration of periodic upgrades incorporating the expanding features of that standard should be part of the continuing quality-improvement program. Equipment guidelines cover two basic categories of teleradiology when used for rendering the official interpretation: small matrix size (e.g., computed tomography [CT], magnetic resonance imaging [MRI], ultrasound, nuclear medicine, digital fluorography, and digital angiography) and large matrix size (e.g. digital radiography and digitized radiographic films). Small matrix: The data set should provide a minimum of 512 x512 matrix size at a minimum 8-bit pixel depth for processing or manipulation with no loss of matrix size or bit depth at display.
CR STANDARDS Teleradiology
General Diagnostic Radiology
Large matrix: The data set should allow a minimum of 2.5 lp/mm spatial resolution at a minimum 10-bit pixel depth.
A. Acquisition or Digitization
1. Direct image capture
The entire image data set produced by the digital modality both in terms of image matrix size and pixel bit depth should be transferred to the teleradiology system. It is recommended that the DICOM standard be used.
2. Secondary image capture
a. Small matrix images. Each individual image should be digitized to a matrix size as large or larger than that of the original image by the imaging modality. The images should be digitized to a minimum of 8 bits pixel depth. Film digitization or video frame grab systems conforming to the above specifications are acceptable.
b. Large matrix images. These images should be digitized to a matrix size corresponding to 2.5 lp/mm or greater, measured in the original detector plane. These images should be digitized to a minimum of 10 bits pixel depth.
3. General requirements
At the time of acquisition (small or large matrix), the system must include: Annotation capabilities including patient name, identification number, date and time of examination, name of facility or institution of acquisition, type of examination, patient or anatomic part orientation (e.g., right, left, superior, inferior), and amount and method of data compression. The capability to record a brief patient history is desirable.
B. Compression
Data compression may be used to increase transmission speed and reduce storage requirements. Several methods, including both reversible and irreversible techniques, may be used, under the direction of a qualified physician, with no reduction in clinically significant diagnostic image quality. The types and ratios of compression used for different imaging studies transmitted and stored by the system should be selected and periodically reviewed by the responsible physician to ensure appropriate clinical image quality.
C. Transmission
The type and specifications of the transmission devices used will be dictated by the environment of the studies to be transmitted. In all cases, for official interpretation, the digital data received at the receiving end of any transmission must have no loss of clinically significant information. The transmission system shall have adequate error-checking capability.
D. Display Capabilities
Display workstations used for official interpretation and employed for small matrix and large matrix systems should provide the following characteristics:
1. Luminance of the gray-scale monitors should be at least 50 foot-lamberts.
2. Lighting in the reading room should be controlled to eliminate reflections in the monitor and to lower the ambient lighting level as much as is feasible.
3. Capability for selecting image sequence.
4. Capability of accurately associating the patient and study demographic characterizations with the study images.
5. Capability of window and level adjustment, if those data are available.
6. Capability of pan and zoom functions.
7.Capability of rotating or flipping the images provided correct labeling of patient orientation is preserved.
8. Capability of calculating and displaying accurate linear measurements and pixel value determinations in appropriate values for the modality (e.g., Hounsfield units for CT images), if those data are available.
9. Capability of displaying prior image compression ratio, processing, or cropping.
10. Should have the following elements of display available:
a. Matrix size.
b. Bit depth.
c. Total number of images acquired in the study.
d. Clinically relevant technical parameters. When the display systems are not used for the official interpretation, they need not meet all the characteristics listed above.
E. Archiving and Retrieval If electronic archiving is to be employed, the guidelines listed
below should be followed:
1. Teleradiology systems should provide storage capacity sufficient to comply with all facility, state, and federal regulations regarding medical record retention. Images stored at either site should meet the jurisdictional requirements of the transmitting site. Images interpreted
off-site need not be stored at the receiving facility, provided they are stored at the transmitting site.
However, if the images are retained at the receiving site, the retention period of that jurisdiction must be met as well. The policy on record retention must be in writing.
2. Each examination data file must have an accurate corresponding patient and examination database record, which includes patient name, identification number, examination date, type of examination, and facility at which examination was performed. It is desirable that space be available for a brief clinical history.
3. Prior examinations should be retrievable from archives in a time frame appropriate to the clinical needs of the facility and medical staff.
4. Each facility should have policies and procedures for archiving and storage of digital image data equivalent to the policies for protection of hard-copy storage media to preserve imaging records.
F. Security
Teleradiology systems should provide network and software security protocols to protect the confidentiality of patients’ identification and imaging data consistent with federal and state
legal requirements. There should be measures to safeguard the data and to ensure data integrity against intentional or unintentional corruption of the data.
G. Reliability and Redundancy
Quality patient care may depend on timely availability of the image interpretation. Written policies and procedures should be in place to ensure continuity of teleradiology services at a level consistent with those for hard-copy imaging studies and medical records within a facility or institution. This should include internal redundancy systems, backup telecommunication links, and a disaster plan.
V. LICENSING, CREDENTIALING, AND LIABILITY
Physicians who provide the official interpretation of images transmitted by teleradiology should maintain licensure as may be required for provision of radiologic service at both the transmitting and receiving sites. When providing the official interpretation of images from a hospital, the physician should be credentialed and obtain appropriate privileges at that institution. These physicians should consult with their professional liability carrier to ensure coverage in both the sending and receiving sites (state or jurisdiction). The physician performing the official interpretations is responsible for the quality of the images being reviewed. Images stored at either site should meet the jurisdictional requirements of the transmitting site. Images interpreted off-site need not be stored at the receiving facility, provided they are stored at the transmitting site. However, if images are retained at the receiving site, the retention period of that jurisdiction must be met as well. The policy on record retention should be in writing. The physicians who are involved in practicing teleradiology will conduct their practice in a manner consistent with the bylaws, rules, and regulations for patient care at the transmitting site.
VI. DOCUMENTATION
Communication is a critical component of teleradiology. Physicians interpreting teleradiology examinations should render reports in accordance with the best Standard for Communication: Diagnostic Radiology.
VII. QUALITY CONTROL AND IMPROVEMENT, SAFETY, INFECTION CONTROL, AND PATIENT EDUCATION CONCERNS
policies and procedures related to quality, patient education, infection control, and safety should be developed and implemented on Quality Control and Improvement, Safety, Infection Control, and Patient Education Concerns appearing elsewhere. Any facility using a teleradiology system must have documented policies and procedures for monitoring and evaluating the effective management, safety, and proper performance of acquisition, digitization, compression, transmission, archiving, and retrieval functions of the system. The quality-control program should be designed to maximize the quality and accessibility of diagnostic information. A test image, such as the SMPTE test pattern, should be captured, transmitted, archived, retrieved, and displayed at appropriate intervals, but at least monthly, to test the overall operation of the system under conditions that simulate the normal operation of the system. As a spatial resolution test, at least 512 x 512 resolution should be confirmed for small-matrix official interpretation, and 2.5 lp/mm resolutions for large-matrix official interpretation. As a test of the display, SMPTE pattern data files sized to occupy the full area used to display images on the monitor should be displayed. The overall SMPTE image appearance should be inspected to assure the absence of gross artifacts (e.g., blurring or bleeding of bright display areas into dark areas or aliasing of spatial resolution patterns). Display monitors used for primary interpretation should be tested at least monthly. As a dynamic range test, both the 5% and the 95% areas should be seen as distinct from the respective adjacent 0% and 100% areas.
2 The Rules of Ethics state: “it is proper for a diagnostic radiologist to provide a consultative opinion on radiographs and other images regardless of their origin. A diagnostic radiologist should regularly interpret radiographs and other images only when the radiologist reasonably participates in the quality of medical imaging, utilization review, and matters of policy which affect the quality of patient care.”
Nepal and Teleradiology
Nepal has a large rural population and the number of radiologists is very less. So the importance of Teleradiology is more in Nepal.
Where to find more:
The essential physics of medical imaging
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