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Original Research |
1 Department of Diagnostic Radiology, Yale University School of Medicine 333
Cedar Street, TE-2, New Haven, CT 06510.
2 Department of Surgery, Division of Emergency Medicine, Yale University School
of Medicine, New Haven, CT.
3 Also affiliated with Yale School of Management, Yale College Department of
Economics, and Yale School of Public Health, New Haven, CT.
Received May 13, 2005;
accepted after revision June 28, 2005.
Address correspondence to H. P. Forman
(howard.forman{at}yale.edu).
Abstract
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MATERIALS AND METHODS. We surveyed 113 radiology chairpersons associated with U.S. academic medical centers using a survey approved by our institutional review board. The need for informed consent for this study was waived. Chairpersons were asked if their institutions have guidelines for nonemergent CT scans (by whom; oral and/or written), if patients are informed of the purpose of their scans (by whom), what specific risks are outlined (allergic reaction, radiation risk and dose, others; by whom), and if patients are informed of alternatives to CT.
RESULTS. The study response rate was 81% (91/113). Of the respondents, two thirds (60/90) currently have guidelines for informed consent regarding CT scans. Radiology technologists were most likely to inform patients about CT (38/60, 63%) and possible risks (52/91, 57%), whereas ordering physicians were most likely to inform patients about CT's purpose (37/66, 56%). Fifty-two percent (30/58) of sites provided verbal information and 5% (3/58) provided information in written form. Possible allergic reaction to dye was explained at 84% (76/91) of sites, and possible radiation risk was explained at 15% (14/91) of sites. Nine percent (8/88) of sites informed patients of alternatives to CT.
CONCLUSION. Radiology technologists are more likely to inform patients about CT and associated risks than their physician counterparts. Although most academic medical centers currently have guidelines for informed consent regarding CT, only a minority of institutions inform patients about possible radiation risks and alternatives to CT.
Keywords: cancer • CT • informed consent • radiation dose • radiation risk • radiology practice
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The organ doses from CT examinations are generally higher than those of conventional radiographs [8], and the effective doses from CT scans are within the range experienced by atomic bomb survivors who experienced a small but statistically significant increase in solid cancer risk [9] and cancer mortality [10]. More recently, studies have supported an increased lifetime cancer risk among the pediatric population undergoing diagnostic CT scans [11, 12] and adults undergoing elective full-body CT screenings [13]. In January 2005, the National Toxicology Program of the National Institutes of Health acted to permanently categorize radiation as a known human carcinogen [14].
Of particular interest to those in the field of radiology are the ethical and legal implications of increased CT use and the purported increased cancer risks. The fundamental principle of informed consent states that patients should be provided sufficient information, in a manner that they can understand, to make an informed decision about their care [15]. Such disclosure must include the benefits, the possible risks of the procedure, and the alternatives—including foregoing the CT scan altogether—to be considered a complete informed consent [16].
To date, informed consent for radiation dose and possible associated risks have not been examined in great detail in the medical literature. Past studies examining informed consent for IV contrast media have elucidated a desire among patients to be educated about medical issues such that they may participate as partners in medical decisions [17-19]. It has been argued that informed consent should be obtained from all patients to provide them with correct information about the radiation exposure and lifetime cancer risk as they are currently understood to respect patient autonomy [20-22].
The purpose of this study was to characterize the current informed consent practices for diagnostic CT scans at U.S. academic medical centers, including whether disclosure of possible radiation risks is a standard part of informed consent procedures, and to identify who is best positioned to obtain such informed consent. We hypothesized that most academic medical centers currently do not have guidelines regarding informed consent for diagnostic CT scans, and that patients, while being informed of possible reactions to contrast dye by a technologist, are not informed of radiation exposure, possible lifetime cancer risks, and alternatives to CT scans.
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The cover letter and survey were first distributed electronically to the 113 U.S. SCARD members during the last week of October 2004. The electronic mailing was followed up with a postal mailing 1 week later to all invited participants who had not responded. Participants were given 3 weeks to complete the survey and return it via electronic mail or a self-addressed stamped envelope provided in the regular mailing. Finally, all participants who had not returned their surveys by the first week of December 2004 were contacted by telephone to ensure they had received and reviewed the study material, and to minimize the amount of data lost to follow-up.
Institutional Guidelines
Study participants were asked several multipart questions and given a
selection of check-box answers and blank space to write their own answers.
First, department chairpersons were asked if their institution currently has
guidelines for informing patients (who are not in an emergent,
life-threatening state) about the nature of their diagnostic CT scan before it
is administered. Answer choices included yes, no, and I don't know. If
answering yes, participants were asked who in their institution usually
provides the patient information about the nature of their CT scan. Answer
choices included the ordering physician, radiologist, radiology technologist,
I don't know, and a space for other answers. Institutions with current
guidelines were also asked by what method their patients are informed about
their CT scans. Answer choices included oral, written, both oral and written,
and I don't know.
CT Scan Purpose
Second, study participants were asked if patients at their institution (who
are not in an emergent, life-threatening state) are informed of the purpose of
the CT scan before it is administered. Answer choices included yes, no, and I
don't know. If answering yes, participants were asked by whom patients are
informed about the nature of their CT scan. Answer choices included the
ordering physician, radiologist, radiology technologist, I don't know, and a
space for other answers.
CT Scan Risks
Third, study participants were asked which specific risks are outlined to
patients pending CT scan for the evaluation of a nonemergent condition.
Participants were asked to check all answers that applied. Answer choices
included possible allergic reaction to contrast dye, possible radiation risk
from the procedure, the mention of actual radiation dose, I don't know, and a
space for other answers. If any specific risks were outlined, study
participants were asked who in their institution usually provides the patient
information about the risks of their CT scan. Answer choices included the
ordering physician, radiologist, radiology technologist, I don't know, and a
space for other answers.
CT Scan Alternatives
Finally, study participants were asked if their institution informed
patients pending CT scan for the evaluation of a nonemergent condition of
alternatives to the CT scan before it is administered. Answer choices included
yes, no, and I don't know. If answering yes, participants were asked by what
method patients are informed about the nature of their CT scan. Answer choices
included the ordering physician, radiologist, radiology technologist, I don't
know, and a space for other answers.
Data Analysis
Completed survey data also included geographic information and data
regarding affiliation with a public or private university. All data were
stripped of personal identifiers before analysis by the study team. Given that
the data were descriptive in nature and initial chi-square test analyses
yielded no statistical significance, further statistical analyses were
unnecessary and all results are reported here in a purely descriptive manner.
Because participants were able to select more than one answer choice for
several questions, the final percentage response was greater than 100% for
some items.
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Institutional Guidelines
Nearly two thirds (60/90) of the respondents reported that their
institutions currently have overall guidelines for informing patients
considering having a CT scan for the evaluation of a nonemergent condition
about their scan before it is administered. At the medical centers that
reported they have such guidelines, the radiology technologist (42%, 38/60)
was most likely to provide the patient with information about the nature of
the CT scan, followed by the ordering physician (21%, 19/60), and then the
attending radiologist (15%, 14/60). Other sources of information for the
patient regarding the nature of a CT scan included nurses, residents, and
clerical staff (Tables 3 and
4).
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Of the academic medical centers that reported they have overall guidelines for informing patients about CT scans, 50% (30/60) provided the information verbally and 42% (25/60) provided the information in both written and verbal formats. Three sites (5%) provided patients with written information only. Two of the sites that reported their institutions have guidelines for providing patients with information did not respond to this item (Table 5).
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CT Scan Purpose
Sixty-six of 91 (73%) academic medical centers reported they regularly
inform patients about the purpose of their CT scans. Five respondents reported
they did not know whether patients are informed of the purpose of their CT
scans, and one survey participant chose not to respond to this item. Of the
centers that do inform patients regarding the purpose of their CT scans
(66/91), 56% (37/66) reported that the ordering physician usually informs
patients about the purpose of CT scans and 53% (35/66) reported that the
radiology technologist usually serves this role
(Table 6). Four medical centers
reported that a resident or fellow usually performs this task, and two centers
reported that nurses usually perform this task.
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CT Scan Risks
Most (84%, 76/91) responding academic medical centers informed patients
about the risk of possible allergic reactions to contrast material before
administering it for CT scans. In comparison, only 15% (14/91) informed
patients about possible radiation risks from the CT scans, and only one site
(1.1%, 1/91) mentioned the actual radiation dose to patients. Five respondents
did not know which risks were outlined to patients, and three academic medical
centers did not outline any risks to patients. Other risks of CT that were
explained to patients included radiation risks to pregnant patients and risk
of nephrotoxicity. Of the centers that provide risk-related information to
patients, radiology technologists were the most likely source of this
information, followed by attending radiologists. Others involved in explaining
risks to patients included nurses, residents, and ordering physicians (Tables
7 and
8).
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CT Scan Alternatives
Sixty-five of 88 (74%) responding academic medical centers do not inform
patients of possible alternatives to CT scans before their administration.
Only eight of 88 centers (9%) routinely inform patients of alternatives to CT
scans. Fifteen of 88 respondents (17%) did not know whether their medical
center informed patients of diagnostic alternatives, and three respondents did
not respond to this item (Table
9). Of the eight sites that provide patients with information
regarding alternatives to CT scans, four of eight (50%) respondents reported
the ordering physician provides patients with such information. Three of eight
centers (38%) reported the radiologist provides patients with information
regarding alternatives to CT, and one of eight centers (13%) identified the
radiology technologist as the source of this information.
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Although the United States has no current national guidelines for informing patients about radiation exposure with diagnostic CT scans, the European Union has codified into law the requirement that all CT dose information accompany electronically stored image data for patients and that anyone referring a patient for a radiologic examination must provide "sufficient medical data" to justify the study [24, 25]. Moreover, U.S. physicians must obtain consent from patients before performing any procedure or risk charges of assault and battery [23]. Furthermore, for the patient's consent to be valid under law, the patient must have sufficient information on which to base the decision [26].
Our study shows that 50% of patients are verbally informed about CT scans in academic medical centers, and 5% receive only written information. The remaining 42% of sites use both verbal and written methods of consent. This study finding agrees with previous studies that have examined informed consent for IV injection of contrast material before radiographic studies [27]. Although written consent procedures are reproducible, create documentation, and standardize the communication of risks, limitations in obtaining written informed consent are numerous including patient understanding, legal department time, and costs [17]. Also, patients may prefer to obtain information person-to-person, enabling discussion with health care providers and offering opportunities for clarification and support [28].
In routine health care delivery, providers may be comfortable eliciting an "informal" informed consent from patients. However, this informality should not undermine the need for patients to understand a test's indications and appreciate its benefits, risks, and limitations [29]. In the case of diagnostic CT scans, which some would categorize as routine delivery of care, this principle still holds. Based on our study's findings, we contend that this information is currently disseminated to patients through a combination of written and verbal methods. The findings also suggest that providing patients with information necessary to make an informed decision regarding diagnostic CT scans occurs in two parts: (1) at the time the ordering physician informs the patient about the purpose of the CT scan, and (2) when the radiology technologist discloses the associated risks of CT.
CT Scan Purpose
Our results show that the ordering physician is most likely to inform
patients about the need for the diagnostic CT scan; however, this duty is
sometimes left to others, most commonly the radiology technologist. This same
technologist is also the person most likely to inform patients about possible
risks. For interventional radiology procedures, most authorities agree that
the radiologists should obtain informed consent
[16,
23]. Although diagnostic
studies are not as invasive as interventional procedures, informed consent for
such studies is usually left to caretakers other than the radiologist.
Most of the information communicated to patients after the disclosure of the purpose of the examination by the ordering physician occurs between the radiology technologist and patient before, during, and after the CT scan. Although the radiology technologist has more direct interactions with the patient regarding the CT scan, liability associated with obtaining informed consent may still involve the radiologist. Thus, if radiology technologists continue to play a large role in the consent process it is important that the radiology community ensure that technologists are educated and trained to provide necessary information to patients concerning the risks, benefits, and alternatives to CT scans.
CT Scan Risks
Currently, radiation exposure and associated risks from diagnostic CT scans
are explained to patients in approximately one in eight academic medical
centers in comparison with risk associated with contrast administration, which
is explained to patients in five of six such centers. Given that guidelines
are currently in place at most academic medical centers to disclose the rare
morbidity and mortality attributed to acute allergic reactions, we believe
that the morbidity and mortality attributable to radiation exposure should
also be explained. Low-dose radiation is an important and necessary medical
tool, but it is also considered a carcinogen
[30] and should be disclosed
for both ethical and legal reasons.
Contrary to arguments that informing patients about possible risks would cause them undo anxiety, past studies have shown that in most cases disclosure of possible IV contrast reactions did not alter anxiety [31]. Furthermore, 90% of patients given a description of risks associated with radiographic contrast material just before undergoing a CT examination said they would rather receive this information than not receive it [17]. Written consent for IV contrast also did not lessen the number of studies performed and offered more specific information to the patient regarding possible complications [32].
From a medical-legal standpoint, the malpractice risks arising from allegations of radiation injury caused by CT are yet unknown and, thus, unlimited [33]. Thus, it would be prudent for the radiology community to disclose possible radiation risks. In the past, a large part of the limitations in the use of clinical radiology consent forms have been the patient's inability to understand them. Consent forms for radiologic procedures have been shown to require a college education to understand [34], and basic information directed at an eighth grade level of education is recommended [35]. One suggested and simple way of communicating the radiation risk to patients is to express radiation dose as multiples of chest radiographs, a method that is widely understood and endorsed by the European Commission's guidelines on imaging [36].
CT Scan Alternatives
Fewer than 10% of academic medical centers returning surveys stated that
they currently inform patients of alternatives to diagnostic CT scans. Without
disclosure of alternative diagnostics, which include not undergoing a CT
examination at all, the medical community is currently not obtaining complete
and thorough informed consents from patients before administration of CT.
Critics have argued that the time, legal resources, and finances to outline
all major benefits, risks, and alternatives to patients would be too costly
[37]. Yet, given the large
proportion of academic medical centers that report already having guidelines
in place regarding many aspects of informed consent for diagnostic CT scans,
we believe that complete disclosure of the benefits, all major risks
(including risk from ionizing radiation), and alternatives is currently
possible without much added effort, time, or infrastructure.
Study Limitations
Although chairpersons of each medical center's radiology department were
targeted for ease of participant identification and uniformity of data
collected, we acknowledge that the chairpersons may not be as involved in
patient care as other physicians in their department. Data from this study are
descriptive in nature, and no statistical analyses of significance could be
performed. Also, some items allowed respondents to select more than one answer
choice, yielding a total greater than 100% response for select survey
questions. Finally, although much of the debate concerning unnecessary
radiation exposure to patients is occurring in the outpatient community
setting, our data are specific to U.S. academic medical centers.
Recommendations
We recommend that the U.S. governing radiologic bodies follow the lead of
the European Union and move to develop national policy guidelines regarding
screening and diagnostic CT-scan informed consent practices, and proper
disclosure of radiation dose and possible cancer risks to all patients
involved. Although most academic medical centers currently have guidelines for
informing patients regarding CT scans, its purpose, and some risks, they are
not obtaining full informed consent because of the failure of disclosing both
the radiation risks and diagnostic alternatives. Such practices disregard
patient autonomy and violate common principles of medical ethics.
In particular, physicians and technologists should be educated about the magnitude of diagnostic CT radiation dose and possible long-term consequences. The disparity in knowledge regarding radiation dose from CT scans between radiologists and nonradiologists suggests that current information is not being disseminated from the radiology community to either requesting physicians or patients [38]. Whether provided verbally, in written form, or both, correct and understandable information concerning possible radiation risks among physicians and patients will help the medical community avoid a substantial public health risk and possible malpractice lawsuits.
Acknowledgments
We thank the members of the Society of Chairmen in Academic Radiology
Departments (SCARD) for their willingness to aid in the dissemination of the
study survey.
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