Delegation of the Primary Responsibility for MRI Informed Consent to Technical Assistants

Findings from the NAKO health study

As part of the German National Cohort health study (NAKO for short), specially trained technical assistants (TA) take primary responsibility to obtain informed consent from volunteers for non-contrast full-body magnetic resonance imaging (MRI). The process differs from clinical practice in that the TAs not only conduct a preparatory discussion with the patient but are also responsible for the informed consent that is otherwise obtained by medical staff.

The aim of the present study is to analyze termination frequencies, their reasons, and complications associated with the MRI examinations of more than 10 000 participants after informed consent had been obtained by non-medical staff according to the study protocol.

MRI examinations have established themselves as low-risk procedures with an associated low termination frequency of one to two percent (1). The main reason given for termination is usually discomfort due to the confined space in the MRI machine (1). Nevertheless, a standardized and safety-oriented procedure for risk prevention is extremely important, as three elements of the machine technically interact with the person being examined during the MRI scan: 1. the static magnetic field (attractive forces on foreign bodies, implants), 2. audible, pulsed-gradient magnetic fields (muscle twitching), and 3. high-frequency fields (patient heating, burns, interference with implanted electronic devices) (2). These interactions represent only minor or avoidable risks.

Generally, the responsibility for informed consent and examination in everyday clinical practice is delegated to medical staff (3). They may also delegate tasks that are otherwise part of the doctor-patient relationship to qualified personnel but which do not require a physician’s expertise (Federal Court of Justice ref. nr.: VI ZR 72/74). Informed consent by a TA for an MRI examination without administration of a contrast agent therefore falls into this category and does not constitute explanation of risks and possible complications. During the NAKO, there is no legal doctor-patient relationship, and the precondition for the capacity to obtain informed consent is regulated by a certification based on the Imaging Core for Coordination and Training.

Methods

After obtaining approval from the Ethics Committee of the Medical Faculty of the University of Duisburg-Essen, a full body MRI examination was performed on 10 442 participants (48.6% women, 51.4% men; 13.4% under 40 years of age, 75.2% 40–65 years, 11.4% >65 years) during the period January 01, 2014, thru December 31, 2016, after informed consent had been obtained by TAs (a total of 62 certified individuals). The protocol, comprising 16 sequences (Table), was completed at five MRI centers of the total of 18 NAKO centers.

Table

Order of all MRI sequences performed and their anatomical allocation*

Examinations that had at least one interruption or were completely terminated were categorized according to the reason for discontinuation (by participant or TA) and subjected to further analysis. The impact of the MRI examination on the mental state of the patient was not explored.

Results

No participants came to harm during any of the investigations. Six hundred and nine (5.8%) of the examinations were terminated either by the participants (n = 404) or the TA (n = 205) for various reasons (Figure). The time of, and reason for, the terminations are detailed in the Table.

Figure

Reasons for termination

Discussion

As expected, the present study confirms MRI as a low-risk imaging modality with a low termination frequency. The termination rate by participants (3.9% of 10 442) is twice as high as that in a cohort study comprising over 50 000 participants (2.1% terminations in total) (1). The lower termination rate (only 0.7%) of this prospective cohort study conducted from 1984 thru 2005, using more modern MRI scanners from 2004 onwards, appears to be explained by the reduced noise exposure and their less restrictive design. The construction of today’s MRI scanners is comparable to the latter group. The lower termination rate of the above cohort study can be attributed to less stressful examination protocols: in 42.3% of cases, head and neck examinations were performed as opposed to full-body examinations; in 14.3%, positioning was done feet first (termination frequency 0.2%). Furthermore, the cohort study examined patients with clinical symptoms who were more highly motivated. The participants in the present study ended the examination during the first sequence in 44.2% (n = 269) of cases.

Transferring primary responsibility to specially trained TAs, including the explanation of risks and possible complications (MRI with contrast agent administration), could reduce the workload of the medical service. In English-speaking countries, nurse practitioners/physician assistants have established themselves as TAs with additional qualifications who can take on some of these tasks (4). There is a high level of acceptance for the theoretical transfer of medical tasks to TAs for minor illnesses (5).

The limitation is that this retrospective cross-sectional analysis of centrally collected study data does not represent a systematic prospective survey of all participants, which would have enabled a more comprehensive database query and documentation of side effects and serious side effects. The descriptive study design does not include a comparison group of participants informed by physicians, so that a direct association between the termination rate and the informed consent by TAs cannot be methodologically proven within this study and TAs cannot be resolved as possible cause for termination (confounding factor). Due to the study design and the group of people responsible for the informed consent, these results are not comparable with other population studies. Whereas the UK Biobank study did not document whether TAs or medical staff conducted the informed consent, in other population studies contrast agents were applied and only medical staff were responsible for providing the informed consent (Hamburg Health, SCAPIS, SHIP, and MESA).

In summary, the use of modern high-performance MRI scanners for population-based research remains a low-risk modality, and the assumption of responsibility by TAs within safety management is an adequate approach.

Anton Sheahan Quinsten, Johannes Haubold, Thomas Kröncke, Lena Friedrich, Tobias Pischon, Thoralf Niendorf, Michael Forsting, Norbert Hosten, Henry Völzke, Fabian Bamberg, Christopher L. Schlett, Hans-Ulrich Kauczor, Simone Brandelik, Jens Theysohn

Our thanks go to the sponsors of the NAKO health study: BMBF (funding codes 01ER1301A/B/C and 01ER1511D), Federal States, the Helmholtz Association, the Institutes of the Leibniz Association.

Conflict of interest statement

FB: Support by the Speakers’ Bureau (Siemens Healthineers) and by the Unrestricted Research Grant (Siemens Healthineers)

CLS: Grants from the Speaking Bureau Siemens Healthineers

The other authors confirm that there are no conflicts of interest.

Manuscript received on 18 June 2023, revised version accepted on 12 December 2023

Translated from the original German by Dr Grahame Larkin MD.

Cite this as:
Quinsten AS, Haubold J, Kröncke T, Friedrich L, Pischon T, Niendorf T, Forsting M, Hosten N, Völzke H, Bamberg F, Schlett CL, Kauczor HU, Brandelik S, Theysohn J: Delegation of the primary responsibility for MRI informed consent to technical assistants—findings from the NAKO health study. Dtsch Arztebl Int 2024; 121: 228–9.
DOI: 10.3238/arztebl.m2023.0273

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