- Email: [email protected]
Storing Medical Images in the Digital Age: The Need for Universal and Technologically Appropriate Guidelines
OPINION
Storing Medical Images in the Digital Age: The Need for Universal and Technologically Appropriate Guidelines Jonathan L. Mezrich, MD, JD, LLM, MBA, Eliot Siegel, MD
Data storage has always represented a balancing act between the utility and need to maintain data and the physical and technological limitations of storage capacity and retrieval time incumbent in storing, cataloging, and manipulating data. At one time, the storage and maintenance of radiologic images were Herculean chores. Today the file room has been reduced to a handful of spinning disks. With the elimination of film, we are no longer faced with the issues of time-related image degradation and loss.
WHY DO WE RETAIN IMAGES? Comparison Studies Much as radiologists tend to make better diagnoses when provided with an accurate history, radiologists also do better with access to prior imaging. A finding such as a lung nodule will be less concerning if it has been stable over time. Defensive Practice It is hard to defend against the claim that a finding was already visible on a prior study even when you have access to the prior study, but nearly impossible without such access. Many patients are provided with
DVDs containing their examinations, so hospitals may even find themselves defending against imaging studies they created that are in the plaintiff’s possession but no longer their own.
State and Federal Requirements Medicare and most states require that all medical records, including imaging, must be maintained for a specific period of time, usually at least 5 years [1,2]. Longer retention may be required for specific types of imaging, such as mammography, pediatric patients, and toxic exposures [3 (at 125-6)]. When multiple requirements are in play, the longest retention period will generally need to be satisfied [3]. State laws requiring storage of images are meant to represent an absolute legal requirement, not a clinical practice minimum or guideline. The specialty is free to adhere to a higher standard of care. The ACR has issued its own opinion that images should be retained for longer than state or federal retention requirements, to the extent that a statute of limitations permits the subsequent filing of a medical malpractice case, often an additional 2 or 3 years after a malpractice claim would reasonably
ª 2017 Published by Elsevier on behalf of American College of Radiology 1546-1440/17/$36.00 n http://dx.doi.org/10.1016/j.jacr.2017.02.029
be discovered [4]. As such, there is no clear-cut answer as to how long one must retain images for every case. It should be noted that the record retention obligation is not radiologyspecific and likely includes all facilities/physicians who utilize imaging (see, for example, Maryland code [5]).
Spoliation The “Spoliation” rule provides that when evidence, such as portions of the medical record (including radiographic imaging), is lost, destroyed, or suppressed, a jury will be entitled to presume that the missing evidence would be unfavorable to the party responsible for its unavailability [3 (at 126)]. One commentator has noted: “Even the allegation that a defendant radiologist lost a patient’s PACS images could be perceived by a jury as deceit or fraud, resulting in a radiologist’s being deemed liable for malpractice despite any concrete evidence .” [3 (at 215)]. There are many examples in the literature of litigation over disappearance of radiographs [6,7]. Thus, in addition to record retention being a statutory legal requirement, it can also result in prejudicial treatment in a medical malpractice suit. Legal recommendations associated with the electronic medical record have
1
traditionally been to retain any data that were used to make diagnostic or therapeutic decisions. Radiologists should strive to maintain records for as long as they may be legally relevant. In some cases the statute of limitations for a cause of action will even extend several years beyond the life of the patient [8].
Failure to Maintain There are also state fines and penalties for failure to retain files. Under the Maryland Regulations, for example, a health care facility that fails to retain records is subject to an administrative fine of up to $10,000 for all violations cited in a single day, and a health care provider who knowingly violates such provision can be personally liable for fines of up to $1,000 to $5,000, depending on whether it is a first or later offense [9]. Case law also suggests that if a lost or misplaced PACS image results in patient injury, the radiologist, personally, bears the liability, especially if the error is caused by the actions of department personnel under the radiologist’s direct supervision [10]. The radiologist is generally deemed obligated to interpret all such studies, even if unaware of the existence of the study or its loss [10]. Lossy Versus Lossless Compressed Images There are two approaches to image compression: a reversible form, which decreases data redundancy without loss of information—lossless; and an irreversible form of compression, which can permanently remove marginally important information—lossy [11]. The former is not controversial because there is no loss of diagnostic information, but compression is limited to ratios of 2:1 to 3:1 [11]. Lossy compression typically creates a visually similar version of the image 2
but does not store the entirety of the original image data. Technically some information will have been lost or altered, but this technique allows for much greater compression ratios in the range of 7:1 for cross-sectional imaging and 30:1 for radiographs [11]. Whether a lossy image that contains most of the data of the prior image is adequate for comparison purposes is subject to debate. A balance must be struck between storage demands and image quality. The ACR guidelines take no position on how much compression is adequately diagnostic, as long as it is reasonably reliable for the clinical task [12]. The US Food and Drug Administration (FDA) requires that where lossy compression is used, the image is labeled with a statement that irreversible compression has been applied, including the compression ratio and the type of compression scheme [12]. The FDA does not allow lossy compression of digital mammograms for retention, transmission, or final interpretation, but does allow it for images from prior studies [12]. For other modalities, the FDA does not restrict the use of lossy compression [12]. The Canadian Association of Radiologists takes a less conservative approach, and allows as much as 30:1 lossy compression for a radiograph and 24:1 compression ratio for an MRI [13].
The Standard of Care The “standard of care” is the degree of care that a reasonably prudent radiologist (in the community/specialty) should exercise under the same or similar circumstances [14]. To a large extent, the standard of care will be determined in the courtroom setting, based on expert testimony [3 (at 11)]. Widespread practice among radiologists in the community
strengthens the argument that it has become the standard of care. Not meeting the standard of care is strong indicia of malpractice. As a result of the logistical burden of managing the various different retention periods for different patient populations (mammography, pediatric, OSHA, etc.), many radiology practices may not have coordinated programs to purge images from their PACS in accordance with the various state and federal retention requirements. Given the fact that many practices typically retain images beyond these minimum retention requirements, it could be argued that the standard of care in the community may be to retain images indefinitely.
RECOMMENDATIONS AND CONCLUSION Now that we have moved to digital imaging, with plummeting storage costs, is the “5-year retention” rule still valid and reasonable? Is there clinical utility to maintain images for longer than the statutory requirements? Given the multiple different retention periods that could be at play for a given image, it would be burdensome to determine which medical records are permitted to be destroyed under which statute at which time. If you have a PACS with pediatric images, images governed by the Mammography Quality Standards Act, Occupational Safety and Health Administration, and Medicare and one or more state jurisdictions represented, that’s a lot of different rules potentially implicated. It is likely that most facilities do not have a clear sense of how long they need to retain each particular image. PACS databases do not typically create an image retention flag/date. The typical practice at present is thus likely to err on the side of maintaining
Journal of the American College of Radiology Volume - n Number - n - 2017
everything, forever; thus arguably, a practice that endeavors to delete files at the statutory minimum retention date actually runs the risk of running afoul of the “standard of care.” It would be helpful to have a single universal guideline, which could become the standard of care. As things are today, it would have to comport with the lengthiest possible statutory duty—the life of the patient plus any potential statute of limitations. That might create logistical issues, as facilities would need to ascertain dates of death. So a focus on strict retention periods is perhaps misplaced. Digital memory is becoming inexpensive [15,16]. In 2017, cloudbased storage of a gigabyte of information is as low as 0.3 cents per month; less if stored locally [17]. Even assuming a very conservative number of $1 per gigabyte of PACS storage would mean that storing a 500-image CT with and without contrast (about half a gigabyte) would cost about $0.50 per study. It seems likely that it would cost more in administrative costs just to determine whether such a study could be deleted than to retain it. There is some value in having older studies for comparison and defensive purposes. And in this day and age, where we are handing patients DVDs with their medical imaging, they may continue to possess this imaging well beyond the requisite statutory retention periods anyhow, so as radiologists we may be putting ourselves at a legal disadvantage whenever we destroy our own copy.
Although lossless may be selected for the first 5 years after acquisition of an image, when most statutory requirements are in effect, for images older than this initial term, perhaps it would be reasonable for a facility to archive images using lossy compression. Our Canadian counterparts have allowed compression to as much as a 30:1 ratio for certain types of images [13]. Compression at these ratios generally maintains enough image integrity to retain even the least conspicuous findings. It also could be argued that as images become older, even greater compression could be applied, so that images 5 years old might be compressed by X, and over 10 years by 8X, and so on. Finally, we would strongly encourage the development of an ACR image retention guideline with input from expert opinion from the informatics community; we believe this will be useful clinically and from a medicolegal perspective.
5.
6. 7. 8. 9.
10.
11.
12.
13.
REFERENCES 1. HealthIT.gov: Privacy and security solutions for interoperable health information exchange: report on state medical record access laws (August 2009) “Table A-7. State Medical Records Laws.” Available at: https:// www.healthit.gov/sites/default/files/appa7-1. pdf. Accessed October 25, 2016. 2. BW Recycling, Inc: “x-ray retention and disposal periods in all states.” Available at: http://www.xrayfilmsrecycling.com/statelaw/. Accessed October 25, 2016. 3. Eisenberg RL. Radiology and the law: Malpractice and other issues. New York: Springer-Verlag; 2004. 4. American College of Radiology: Digest of council actions, 2015-16, Appendix E, p.133. Available at: http://www.acr.org/w/media/ ACR/Documents/PDF/Membership/Govern
14. 15.
16.
17.
ance/Digest%20of%20Council%20Actions. pdf. Accessed October 25, 2016. Maryland Health-Gen Code Section 4-403 (2015). Available at: http://law.justia.com/ codes/maryland/article-ghg/title-4/subtitle-4/ section-4-403/. Accessed March 19, 2017. Miller v Gupta, 656 NE 2d 461 (IL App Ct 1995). Rodgers v St Mary’s Hospital, 556 NE 2d 913 (1990). Keeton WP. Prosser and Keeton on torts. 5th ed. St Paul, MN: West Publishing; 1984:942-4. Maryland Code of Regulations Section 10.01. 16.09 (March 24, 2008). Available at: http:// www.dsd.state.md.us/comar/comarhtml/10/ 10.01.16.09.htm. Accessed March 20, 1917. Smith JJ, Berlin L. Malpractice issues in radiology: picture archiving and communication systems (PACS) and the loss of patient examination records. Am J Roentgenol 2001;176:1381-4. The American Board of Radiology: Noninterpretive skills domain specification and resource guide, “Image data compression,” 2016, p. 95. Available at: http://www. theabr.org/sites/all/themes/abr-media/pdf/ Noninterpretive_Skills_Domain_Specific ation_and_Resource_Guide.pdf. Accessed October 25, 2016. American College of Radiology: ACRAAPM-SIIM technical standard for electronic practice of medical imaging, amended 2014. Available at: http://www.acr.org/ w/media/AF1480B0F95842E7B163F09F1 CE00977.pdf. Accessed October 25, 2016. CAR standards for irreversible compression in digital diagnostic imaging within radiology, approved 2011. Available at: http:// www.car.ca/uploads/standards%20guidelin es/Standard_Lossy_Compression_EN.pdf. Accessed October 25, 2016. Black HC. Black’s law dictionary. 5th ed. St Paul: West Publishing Co; 1979. Meridian L. Consumer SSDs and hard drive prices are nearing parity. Available at: http://www.computerworld.com/article/30 10395/solid-state-drives/consumer-ssds-an d-hard-drive-prices-are-nearing-parity.html. Accessed October 25, 2016. Statistic Brain Research Institute: Average cost of hard drive storage. Available at: http://www. statisticbrain.com/average-cost-of-hard-drivestorage/. Accessed October 25, 2016. Cloudwards.net. Available at: http:// www.cloudwards.net/comparison/. Accessed October 25, 2016.
Jonathan L. Mezrich, MD, JD, LLM, MBA, is from the Department of Diagnostic Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut. Eliot Siegel, MD, is from the Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Medical Center, Baltimore, Maryland. The authors have no conflicts of interest related to the material discussed in this article. Jonathan L. Mezrich, MD, JD, LLM, MBA: Department of Diagnostic Radiology and Biomedical Imaging, Yale University School of Medicine, 333 Cedar Street, TE2, New Haven, CT 06520; e-mail: [email protected]. Journal of the American College of Radiology Mezrich, Siegel n Opinion
3
Storing Medical Images in the Digital Age: The Need for Universal and Technologically Appropriate Guidelines Jonathan L. Mezrich, MD, JD, LLM, MBA, Eliot Siegel, MD
Data storage has always represented a balancing act between the utility and need to maintain data and the physical and technological limitations of storage capacity and retrieval time incumbent in storing, cataloging, and manipulating data. At one time, the storage and maintenance of radiologic images were Herculean chores. Today the file room has been reduced to a handful of spinning disks. With the elimination of film, we are no longer faced with the issues of time-related image degradation and loss.
WHY DO WE RETAIN IMAGES? Comparison Studies Much as radiologists tend to make better diagnoses when provided with an accurate history, radiologists also do better with access to prior imaging. A finding such as a lung nodule will be less concerning if it has been stable over time. Defensive Practice It is hard to defend against the claim that a finding was already visible on a prior study even when you have access to the prior study, but nearly impossible without such access. Many patients are provided with
DVDs containing their examinations, so hospitals may even find themselves defending against imaging studies they created that are in the plaintiff’s possession but no longer their own.
State and Federal Requirements Medicare and most states require that all medical records, including imaging, must be maintained for a specific period of time, usually at least 5 years [1,2]. Longer retention may be required for specific types of imaging, such as mammography, pediatric patients, and toxic exposures [3 (at 125-6)]. When multiple requirements are in play, the longest retention period will generally need to be satisfied [3]. State laws requiring storage of images are meant to represent an absolute legal requirement, not a clinical practice minimum or guideline. The specialty is free to adhere to a higher standard of care. The ACR has issued its own opinion that images should be retained for longer than state or federal retention requirements, to the extent that a statute of limitations permits the subsequent filing of a medical malpractice case, often an additional 2 or 3 years after a malpractice claim would reasonably
ª 2017 Published by Elsevier on behalf of American College of Radiology 1546-1440/17/$36.00 n http://dx.doi.org/10.1016/j.jacr.2017.02.029
be discovered [4]. As such, there is no clear-cut answer as to how long one must retain images for every case. It should be noted that the record retention obligation is not radiologyspecific and likely includes all facilities/physicians who utilize imaging (see, for example, Maryland code [5]).
Spoliation The “Spoliation” rule provides that when evidence, such as portions of the medical record (including radiographic imaging), is lost, destroyed, or suppressed, a jury will be entitled to presume that the missing evidence would be unfavorable to the party responsible for its unavailability [3 (at 126)]. One commentator has noted: “Even the allegation that a defendant radiologist lost a patient’s PACS images could be perceived by a jury as deceit or fraud, resulting in a radiologist’s being deemed liable for malpractice despite any concrete evidence .” [3 (at 215)]. There are many examples in the literature of litigation over disappearance of radiographs [6,7]. Thus, in addition to record retention being a statutory legal requirement, it can also result in prejudicial treatment in a medical malpractice suit. Legal recommendations associated with the electronic medical record have
1
traditionally been to retain any data that were used to make diagnostic or therapeutic decisions. Radiologists should strive to maintain records for as long as they may be legally relevant. In some cases the statute of limitations for a cause of action will even extend several years beyond the life of the patient [8].
Failure to Maintain There are also state fines and penalties for failure to retain files. Under the Maryland Regulations, for example, a health care facility that fails to retain records is subject to an administrative fine of up to $10,000 for all violations cited in a single day, and a health care provider who knowingly violates such provision can be personally liable for fines of up to $1,000 to $5,000, depending on whether it is a first or later offense [9]. Case law also suggests that if a lost or misplaced PACS image results in patient injury, the radiologist, personally, bears the liability, especially if the error is caused by the actions of department personnel under the radiologist’s direct supervision [10]. The radiologist is generally deemed obligated to interpret all such studies, even if unaware of the existence of the study or its loss [10]. Lossy Versus Lossless Compressed Images There are two approaches to image compression: a reversible form, which decreases data redundancy without loss of information—lossless; and an irreversible form of compression, which can permanently remove marginally important information—lossy [11]. The former is not controversial because there is no loss of diagnostic information, but compression is limited to ratios of 2:1 to 3:1 [11]. Lossy compression typically creates a visually similar version of the image 2
but does not store the entirety of the original image data. Technically some information will have been lost or altered, but this technique allows for much greater compression ratios in the range of 7:1 for cross-sectional imaging and 30:1 for radiographs [11]. Whether a lossy image that contains most of the data of the prior image is adequate for comparison purposes is subject to debate. A balance must be struck between storage demands and image quality. The ACR guidelines take no position on how much compression is adequately diagnostic, as long as it is reasonably reliable for the clinical task [12]. The US Food and Drug Administration (FDA) requires that where lossy compression is used, the image is labeled with a statement that irreversible compression has been applied, including the compression ratio and the type of compression scheme [12]. The FDA does not allow lossy compression of digital mammograms for retention, transmission, or final interpretation, but does allow it for images from prior studies [12]. For other modalities, the FDA does not restrict the use of lossy compression [12]. The Canadian Association of Radiologists takes a less conservative approach, and allows as much as 30:1 lossy compression for a radiograph and 24:1 compression ratio for an MRI [13].
The Standard of Care The “standard of care” is the degree of care that a reasonably prudent radiologist (in the community/specialty) should exercise under the same or similar circumstances [14]. To a large extent, the standard of care will be determined in the courtroom setting, based on expert testimony [3 (at 11)]. Widespread practice among radiologists in the community
strengthens the argument that it has become the standard of care. Not meeting the standard of care is strong indicia of malpractice. As a result of the logistical burden of managing the various different retention periods for different patient populations (mammography, pediatric, OSHA, etc.), many radiology practices may not have coordinated programs to purge images from their PACS in accordance with the various state and federal retention requirements. Given the fact that many practices typically retain images beyond these minimum retention requirements, it could be argued that the standard of care in the community may be to retain images indefinitely.
RECOMMENDATIONS AND CONCLUSION Now that we have moved to digital imaging, with plummeting storage costs, is the “5-year retention” rule still valid and reasonable? Is there clinical utility to maintain images for longer than the statutory requirements? Given the multiple different retention periods that could be at play for a given image, it would be burdensome to determine which medical records are permitted to be destroyed under which statute at which time. If you have a PACS with pediatric images, images governed by the Mammography Quality Standards Act, Occupational Safety and Health Administration, and Medicare and one or more state jurisdictions represented, that’s a lot of different rules potentially implicated. It is likely that most facilities do not have a clear sense of how long they need to retain each particular image. PACS databases do not typically create an image retention flag/date. The typical practice at present is thus likely to err on the side of maintaining
Journal of the American College of Radiology Volume - n Number - n - 2017
everything, forever; thus arguably, a practice that endeavors to delete files at the statutory minimum retention date actually runs the risk of running afoul of the “standard of care.” It would be helpful to have a single universal guideline, which could become the standard of care. As things are today, it would have to comport with the lengthiest possible statutory duty—the life of the patient plus any potential statute of limitations. That might create logistical issues, as facilities would need to ascertain dates of death. So a focus on strict retention periods is perhaps misplaced. Digital memory is becoming inexpensive [15,16]. In 2017, cloudbased storage of a gigabyte of information is as low as 0.3 cents per month; less if stored locally [17]. Even assuming a very conservative number of $1 per gigabyte of PACS storage would mean that storing a 500-image CT with and without contrast (about half a gigabyte) would cost about $0.50 per study. It seems likely that it would cost more in administrative costs just to determine whether such a study could be deleted than to retain it. There is some value in having older studies for comparison and defensive purposes. And in this day and age, where we are handing patients DVDs with their medical imaging, they may continue to possess this imaging well beyond the requisite statutory retention periods anyhow, so as radiologists we may be putting ourselves at a legal disadvantage whenever we destroy our own copy.
Although lossless may be selected for the first 5 years after acquisition of an image, when most statutory requirements are in effect, for images older than this initial term, perhaps it would be reasonable for a facility to archive images using lossy compression. Our Canadian counterparts have allowed compression to as much as a 30:1 ratio for certain types of images [13]. Compression at these ratios generally maintains enough image integrity to retain even the least conspicuous findings. It also could be argued that as images become older, even greater compression could be applied, so that images 5 years old might be compressed by X, and over 10 years by 8X, and so on. Finally, we would strongly encourage the development of an ACR image retention guideline with input from expert opinion from the informatics community; we believe this will be useful clinically and from a medicolegal perspective.
5.
6. 7. 8. 9.
10.
11.
12.
13.
REFERENCES 1. HealthIT.gov: Privacy and security solutions for interoperable health information exchange: report on state medical record access laws (August 2009) “Table A-7. State Medical Records Laws.” Available at: https:// www.healthit.gov/sites/default/files/appa7-1. pdf. Accessed October 25, 2016. 2. BW Recycling, Inc: “x-ray retention and disposal periods in all states.” Available at: http://www.xrayfilmsrecycling.com/statelaw/. Accessed October 25, 2016. 3. Eisenberg RL. Radiology and the law: Malpractice and other issues. New York: Springer-Verlag; 2004. 4. American College of Radiology: Digest of council actions, 2015-16, Appendix E, p.133. Available at: http://www.acr.org/w/media/ ACR/Documents/PDF/Membership/Govern
14. 15.
16.
17.
ance/Digest%20of%20Council%20Actions. pdf. Accessed October 25, 2016. Maryland Health-Gen Code Section 4-403 (2015). Available at: http://law.justia.com/ codes/maryland/article-ghg/title-4/subtitle-4/ section-4-403/. Accessed March 19, 2017. Miller v Gupta, 656 NE 2d 461 (IL App Ct 1995). Rodgers v St Mary’s Hospital, 556 NE 2d 913 (1990). Keeton WP. Prosser and Keeton on torts. 5th ed. St Paul, MN: West Publishing; 1984:942-4. Maryland Code of Regulations Section 10.01. 16.09 (March 24, 2008). Available at: http:// www.dsd.state.md.us/comar/comarhtml/10/ 10.01.16.09.htm. Accessed March 20, 1917. Smith JJ, Berlin L. Malpractice issues in radiology: picture archiving and communication systems (PACS) and the loss of patient examination records. Am J Roentgenol 2001;176:1381-4. The American Board of Radiology: Noninterpretive skills domain specification and resource guide, “Image data compression,” 2016, p. 95. Available at: http://www. theabr.org/sites/all/themes/abr-media/pdf/ Noninterpretive_Skills_Domain_Specific ation_and_Resource_Guide.pdf. Accessed October 25, 2016. American College of Radiology: ACRAAPM-SIIM technical standard for electronic practice of medical imaging, amended 2014. Available at: http://www.acr.org/ w/media/AF1480B0F95842E7B163F09F1 CE00977.pdf. Accessed October 25, 2016. CAR standards for irreversible compression in digital diagnostic imaging within radiology, approved 2011. Available at: http:// www.car.ca/uploads/standards%20guidelin es/Standard_Lossy_Compression_EN.pdf. Accessed October 25, 2016. Black HC. Black’s law dictionary. 5th ed. St Paul: West Publishing Co; 1979. Meridian L. Consumer SSDs and hard drive prices are nearing parity. Available at: http://www.computerworld.com/article/30 10395/solid-state-drives/consumer-ssds-an d-hard-drive-prices-are-nearing-parity.html. Accessed October 25, 2016. Statistic Brain Research Institute: Average cost of hard drive storage. Available at: http://www. statisticbrain.com/average-cost-of-hard-drivestorage/. Accessed October 25, 2016. Cloudwards.net. Available at: http:// www.cloudwards.net/comparison/. Accessed October 25, 2016.
Jonathan L. Mezrich, MD, JD, LLM, MBA, is from the Department of Diagnostic Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, Connecticut. Eliot Siegel, MD, is from the Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland Medical Center, Baltimore, Maryland. The authors have no conflicts of interest related to the material discussed in this article. Jonathan L. Mezrich, MD, JD, LLM, MBA: Department of Diagnostic Radiology and Biomedical Imaging, Yale University School of Medicine, 333 Cedar Street, TE2, New Haven, CT 06520; e-mail: [email protected]. Journal of the American College of Radiology Mezrich, Siegel n Opinion
3