Universal MRI Patient Preparation & Safety

Universal Patient Preparation for Magnetic Resonance Imaging

A Comprehensive Evidence-Based Reference Document

1. Introduction and Rationale

Magnetic resonance imaging represents one of the most diagnostically powerful and physiologically complex modalities in modern medical imaging. Unlike radiography, fluoroscopy, or computed tomography, the safety risks associated with MRI do not arise from ionising radiation but from three distinct physical phenomena that are active continuously during scanner operation: the static magnetic field (B0), the time-varying gradient magnetic fields (dB/dt), and the radiofrequency (RF) electromagnetic field (B1). Each of these constitutes a distinct hazard profile with specific relevance to patient preparation, device screening, and environmental control [1,2].

The consequences of inadequate pre-procedural patient preparation in MRI are disproportionately severe compared with other imaging modalities. Projectile accidents involving ferromagnetic objects, thermal injuries from RF-induced heating of conductive implants or clothing, and device malfunction in patients with active implants are all potentially life-threatening and largely preventable through rigorous, standardised preparation protocols. Deaths and serious injuries have occurred in MRI facilities; such events are most commonly linked to unsafe practices, failure to follow MRI safety policies, or gaps in safety policies and standard operating procedures — equipment failures are rarely the primary cause [1].

The elements of patient preparation described in this document are universal. They apply to every patient, every anatomical region, and every field strength from 1.5 T to 7 T. Preparation elements that are specific to individual anatomical districts or clinical indications (e.g., bowel preparation for MR enterography, bladder filling protocols for pelvic MRI) are intentionally excluded and are addressed in protocol-specific child documents.

2. The ACR Four-Zone Safety Model: Structural Framework for Patient Preparation

Patient preparation does not occur in isolation but is embedded within a physical and operational safety architecture. The most widely adopted international standard is the four-zone model established by the American College of Radiology (ACR), first formalised in the ACR White Paper on MR Safety (2002) and progressively updated through the 2024 edition of the ACR Manual on MR Safety [1,3].

Zone I encompasses public areas outside the MRI environment, including waiting areas, where access is unrestricted. Zone II is the interface between the general public space and the MRI-controlled environment, where patients are brought into the procedural workflow; it is here that patients change into MR-safe gowns and are screened for MR safety issues, with supervision required. Zone III constitutes the control room and areas where the static magnetic fringe field is significant — access is highly restricted to personnel who have been screened and cleared [1,2]. Zone IV is the MRI scanner room itself, where the static magnetic field is continuously present at full strength [1].

The 2024 ACR Manual updates the prior 5-G line convention: a recent revision of the IEC standard IEC 60601-2-33:2022 has revised the fringe field limit to 9 G (0.9 mT), and the ACR endorses this updated standard. Facilities following prior 5-G line recommendations do not require physical adjustments, as the 9-G line is located within (closer to the magnet than) the former 5-G boundary [1,3].

This zonal framework directly governs the sequence and location of all patient preparation activities.

3. Pre-Examination Safety Screening

3.1 Rationale and Mandatory Nature

Safety screening is the single most critical operational step in MRI patient preparation. It is mandatory without exception for every individual — patient, companion, or staff member — prior to entry into Zone III [1].

The ACR recommends a two-level screening process for non-emergent patients:

The first level of screening should take place when the examination is ordered. The MRI staff member scheduling the examination should have basic training in MRI safety and should pose a brief set of screening questions to the referring healthcare provider ordering the study. At a minimum, these questions should include: whether the patient has any implanted cardiac devices (pacemakers, wires, defibrillators) or other active devices (cochlear implants, neurostimulators, infusion pumps); the presence of a cerebral aneurysm clip; and any known metal fragments in critical locations such as the orbit [1].

The second level of screening is performed in Zone II at the time of the examination, consisting of a comprehensive written questionnaire followed by a verbal review with an MRI-trained technologist.

3.2 Standardised Screening Questionnaire: Domains of Inquiry

The screening questionnaire must systematically address the following domains. Each category carries a specific risk profile relative to the three MRI field hazards.

3.2.1 Cardiovascular Implantable Electronic Devices (CIEDs)

Cardiac implantable electronic devices — including pacemakers, implantable cardioverter-defibrillators (ICDs), and cardiac resynchronisation therapy (CRT) devices — pose significant risks during MRI [1,20]. Risks include device reprogramming, inhibition of pacing output, induction of tachyarrhythmias, lead heating, and physical displacement of leads or device housing. The management of patients with CIEDs requires specific protocols beyond the scope of universal preparation and is addressed in dedicated guidelines (currently referenced by the ACR Manual to the Heart Rhythm Society consensus document) [1].

All patients with implanted cardiac pacemakers, implantable cardioverter-defibrillators, diaphragmatic pacemakers, medication pumps, cochlear implants, or other electromechanically activated devices should be precluded from entering Zone IV and prevented from passing the 9-G line unless specifically cleared in writing by a Level 2 MRI Physician or the MRI Medical Director. Documentation defending the risk-benefit rationale must be provided in writing [1].

3.2.2 Intracranial Aneurysm Clips and Neurovascular Devices

Ferromagnetic aneurysm clips represent one of the most historically significant absolute contraindications to MRI. The hazard is displacement of the clip within the cerebral vasculature, with risk of catastrophic haemorrhage. It is essential to ascertain the manufacturer, model number, and material composition of any such clip before proceeding. If it is unclear whether a patient has an implanted intracranial aneurysm clip, plain films should be obtained. Alternatively, if available, recent cranial plain films, CT, or MRI examinations should be reviewed to assess for the presence of such a clip [1].

Critically, a patient with an aneurysm clip who has previously undergone MRI safely at any given field strength cannot be assumed to be safe for subsequent examinations. Variations in static field strength, static field gradient, and orientation of the clip relative to the static field are variables that are impossible to control or reproduce across separate examinations [1].

3.2.3 Other Implanted Devices and Foreign Bodies

The screening questionnaire must address the full spectrum of implanted devices that may interact with one or more MRI fields:

Device Category               | Primary Hazard                         | Action Required

------------------------------|----------------------------------------|--------------------------------------------------- Cochlear implants | Device malfunction, displacement | Manufacturer/model verification; typically MR Unsafe Neurostimulation systems | Device malfunction, lead heating | Manufacturer/model verification; MR Conditional protocols exist for some Infusion pumps | Device malfunction, heating | Remove if possible; verify MR safety status Metallic orthopaedic implants | Heating (uncommon), artefact | Generally MR Safe or MR Conditional; verify for 7T Ocular metallic foreign bodies| Displacement, retinal injury | Orbital radiography if occupational metal exposure Bullets, shrapnel, fragments | Displacement, heating | Risk-benefit assessment based on anatomical location Penile implants, expanders | Displacement, heating | Manufacturer verification required Retained cardiac leads | Heating via antenna effect | Specific precautions required

All patients with a history of injury or implantation associated with a ferromagnetic foreign body must undergo further investigation prior to being permitted entry to Zone III. Acceptable methods include patient history, plain radiographs, prior CT, or documentation of implant type and material [1].

Particular attention is required for patients with a history of occupational metalwork (grinding, welding, metal lathe operation), military service, or trauma: these populations carry increased probability of occult orbital or intra-ocular metallic foreign bodies. Patients with a history of foreign bodies in the eyes will require a negative CT of the orbits prior to admission to Zone III/IV; if CT is not available, skull radiographs in two projections constitute an acceptable alternative [1].

3.2.4 MRI Safety Classification Terminology

The ACR Manual and ASTM International define three universal safety categories applicable to all implants and devices:

MR Safe: Objects that pose no known hazards in any MRI environment. MR Conditional: Objects that pose no known hazards in a defined MRI environment with specified conditions (e.g., field strength <=1.5 T, specific SAR limits, patient positioning requirements). MR Unsafe: Objects that pose unacceptable hazards in any MRI environment; such objects must not enter Zone III or IV.

These classifications apply equally to in-dwelling implants and to external devices including monitoring equipment, infusion pumps, wheelchairs, and patient transport hardware.

3.3 Screening of Unconscious or Incapacitated Patients

Unconscious, sedated, or cognitively impaired patients represent a critical safety challenge, as reliable history cannot be obtained from the patient directly. Family members or guardians of such patients should complete a written MRI safety screening questionnaire prior to the patient's introduction to Zone III. If no reliable patient history can be obtained and the MRI cannot reasonably be delayed, such patients should undergo plain-film radiography of the anatomical regions in question to exclude potentially harmful embedded implants [1].

3.4 Ferromagnetic Detection Systems

The use of ferromagnetic detection systems (FDMS) is recommended as an adjunct to thorough and conscientious screening of persons and devices prior to entry into Zone IV. FDMS is a supplement to, not a replacement for, a thorough screening practice. Conventional metal detectors that do not differentiate between ferrous and non-ferromagnetic materials are not recommended for use in the MRI environment [1].

4. Patient Clothing, Personal Effects, and RF Heating Considerations

4.1 Removal of External Metallic Objects

All patients must remove all externally worn metallic items prior to entry into Zone III. This requirement is absolute and non-negotiable. Items to be removed include, but are not limited to:

• Jewellery of any type (rings, necklaces, bracelets, earrings, body piercings)
• Watches and wearable electronic devices (smartwatches, fitness trackers)
• Hearing aids (external, non-implanted type)
• Hairpins, clips, barrettes, and metallic hair accessories
• Dental appliances that are removable (dentures, removable orthodontic retainers)
• Glasses and spectacles with metallic frames
• Keys, coins, and all pocket contents
• Transdermal medication patches containing metallic components
• Clothing with metallic zippers, clasps, underwire brassières, metallic threads or fibres

The 2024 ACR Manual recommends that patients or research participants remove all clothing, including undergarments, when within the range of RF transmission — for example, within the scanner bore when the built-in body coil is used for RF transmission — and wear site-supplied MR Safe pocketless garments [1].

4.2 Textile Safety and Conductive Fabrics

An emerging and underappreciated safety concern relates to clothing containing electrically conductive fibres. The increasing use of silver or copper fibres for their antimicrobial properties in athletic wear, underwear, and socks increases the likelihood of MRI patients wearing such materials. While silver and copper are non-ferromagnetic, they are excellent electrical conductors, and the risk of induced current and subsequent RF heating exists [9].

Metal zippers located within the RF field region may match the appropriate wavelength of transmitted RF to result in resonance and induce heating in the conductor [9]. Similarly, wearable technology devices that incorporate heart rate or respiratory sensors built into clothing should be treated as MR Unsafe and removed before scanning.

All patients should change into facility-provided MR Safe pocketless gowns or scrubs. Site-provided garments eliminate the risk from unknown textile composition and pocket contents simultaneously.

4.3 Tattoos, Permanent Cosmetics, and Topical Metallic Products

Tattoo-related MRI complications represent a documented but statistically rare phenomenon. Tattoos have been linked with heating and RF burns via the antenna effect, although ferromagnetic pigments in some tattoos may also interact with the static field. Darker tattoo shades appear more prone to reactions. A comprehensive literature review found only 17 published reports of tattoo-related MRI complications, all with full, fast recovery and no lasting sequelae [9,16].

In permanent cosmetic tattoos, the use of iron oxide pigments, sometimes containing the ferrimagnetic substance magnetite, has been identified as a potential ingredient for MRI interactions. The formation of artefacts from permanent eyeliners or eyebrow tattoos during MRI of the head is a recognised phenomenon [16].

In practical terms, the current evidence does not support systematic exclusion of tattooed patients from MRI. The appropriate clinical approach includes:

• Documenting the presence, location, colour, and age of all tattoos and permanent cosmetics;
• Informing patients of the possibility of transient burning or tingling sensations in the tattooed area during the examination;
• Instructing patients to use the emergency alert device immediately if discomfort occurs;
• Applying a cool compress over the tattooed area prior to scanning in high-risk cases.

Makeup, nail polish, and other cosmetics that may contain metallic particles should be removed if applied to the area of the body undergoing MRI examination. This applies particularly to metallic eye shadow, eyeliner, and mascara in patients undergoing brain or head and neck MRI [1].

All transdermal drug delivery patches should be assessed for metallic content. Patches with conductive backing represent a documented burn risk and, where clinically safe, should be removed prior to scanning and replaced after the examination.

5. Patient Identification and Clinical History Verification

Before any patient proceeds to Zone III, positive identification must be confirmed using at least two independent patient identifiers (e.g., full name and date of birth, or full name and hospital identification number). This step is essential to prevent wrong-patient examinations and to ensure that the screening information obtained corresponds to the individual who will undergo the procedure.

Clinical history verification must include:

• Confirmation of the clinical indication and appropriate referral
• Current medication list (particularly anticoagulants, antidiabetics, and metformin)
• Allergy history (with specific emphasis on prior reactions to gadolinium-based contrast agents and on atopic status)
• Prior surgical history (to identify implants that the patient may not recall or be aware of)
• Occupational history (to identify risk of ferromagnetic foreign body exposure)
• Prior MRI history and any documented difficulties (claustrophobia, motion-related scan failure, prior adverse reactions to contrast agents)

6. Pregnancy and Lactation Assessment

6.1 MRI Without Contrast in Pregnancy

Ultrasonography and magnetic resonance imaging are not associated with risk and are the imaging techniques of choice for the pregnant patient, but they should be used prudently and only when use is expected to answer a relevant clinical question or otherwise provide medical benefit to the patient [5].

Both ACOG and the ACR have stated that patients who are pregnant may have an MRI performed during any trimester of pregnancy [5]. Non-contrast MRI does not involve ionising radiation and there is no established evidence of fetal harm attributable to the physical fields used in clinical MRI systems operating at 1.5 T or 3 T.

Institutional policies vary, and it is standard practice to document pregnancy status and obtain written informed consent for MRI examinations during pregnancy, in particular during the first trimester, in accordance with local regulatory requirements and institutional policy [3].

6.2 MRI with Gadolinium-Based Contrast Agents in Pregnancy

The use of GBCAs in pregnancy requires a formal risk-benefit assessment and should not be routine. Gadolinium contrast with MRI may be used in a pregnant woman only if it significantly improves diagnostic performance and is expected to improve fetal or maternal outcome [5].

Gadolinium is known to cross the placenta, and animal studies have demonstrated potential teratogenic effects of GBCAs on developing foetuses. The ACR Committee on Drugs and Contrast Media has noted that there is insufficient evidence to establish a clear association between GBCA exposure during the first trimester and an increased risk of congenital anomalies [14].

The 2016 cohort study by Ray et al. (JAMA) reported a statistically increased risk of stillbirth/neonatal death and childhood rheumatological or skin conditions following GBCA exposure at any point in pregnancy; however, limitations of this study included insufficient sample size to support a statistical comparison of contrast versus non-contrast MRI, inadequate control for the indication prompting MRI, and bundling of rare outcomes [10,15]. Subsequent large-scale studies, including a retrospective analysis of more than 11 million Medicaid-covered pregnancies conducted by the FDA/CDER, have not confirmed these associations. The current consensus recommends avoidance of GBCAs in pregnancy unless clinical necessity is clearly established and non-contrast alternatives are inadequate [1,5,6].

When GBCAs are deemed necessary in pregnancy, macrocyclic agents (classified as Group II by the ACR) are preferred over linear agents due to their superior thermodynamic stability and lower free gadolinium release profile [4].

6.3 Pregnancy Screening Protocol

All women of childbearing age must be asked about current or possible pregnancy before MRI, and specifically before any contrast-enhanced MRI. There is variability in the accuracy of pregnancy tests early in gestation, and at a minimum, testing will be falsely negative in the first two weeks of pregnancy; no screening method is 100% effective in detecting unsuspected pregnancy [7]. Regardless of the screening method employed, women of childbearing age should be informed of this uncertainty prior to any gadolinium-enhanced MRI.

6.4 Breastfeeding and Gadolinium-Based Contrast Agents

Less than 0.04% of an intravascular dose of gadolinium contrast is excreted into breast milk within the first 24 hours, and of this amount, the infant absorbs less than 1% from the gastrointestinal tract. Breastfeeding should not be interrupted after gadolinium administration [5].

This position is endorsed by the ACR Manual on Contrast Media (2024 edition) and by ACOG. Some European guidelines recommend a 24-hour interruption of breastfeeding after GBCA administration, but guidelines developed by several North American professional organisations state that breastfeeding need not be disrupted. The informed decision to temporarily pause breastfeeding should be left to the mother after provision of this information [4,18].

7. Evaluation of Renal Function Prior to Gadolinium-Based Contrast Administration

7.1 Nephrogenic Systemic Fibrosis: Risk Stratification

Nephrogenic systemic fibrosis (NSF) is a fibrotic disorder of the skin, subcutaneous tissue, and visceral organs causally linked to the administration of gadolinium-based contrast agents, predominantly linear-structure agents, in patients with severe renal impairment.

One meta-analysis including seven large series of patients with NSF reported an odds ratio of 26.7 (95% CI 10.3-69.4) for the development of NSF after gadolinium administration in patients with impaired renal function (GFR <30 mL/min/1.73 m2). The incidence of NSF in patients with severe renal dysfunction (GFR <30) varies from 0.19% to 4% in historical series, the overwhelming majority of cases being associated with gadodiamide, gadopentetate dimeglumine, and gadoversetamide — all linear-structure Group I agents [13].

7.2 ACR Classification of GBCAs and Current Risk Assessment

The ACR Manual on Contrast Media classifies GBCAs into groups based on their thermodynamic stability and historical association with NSF:

Group II agents (macrocyclic GBCAs including gadobutrol, gadoterate meglumine, gadoteridol): Extremely low NSF risk at all levels of renal function; currently the recommended agents for all clinical MRI applications.

Group I agents (linear GBCAs including gadodiamide, gadopentetate dimeglumine, gadoversetamide): Substantially higher NSF risk; use is contraindicated or strongly discouraged in patients with eGFR <30 mL/min/1.73 m2 and should be avoided wherever possible.

The 2024 ACR guidelines emphasise that Group II GBCAs should not be withheld in patients with CrCl <30 mL/min/1.73 m2 when clinically indicated. The NSF risk with macrocyclic agents is negligible regardless of renal function [4,8].

7.3 Renal Function Screening Protocol

Routine creatinine or eGFR testing prior to GBCA administration is not required in all patients. Screening is indicated in patients with one or more of the following risk factors:

• Age >60 years
• Known or suspected renal disease (including diabetes mellitus, chronic hypertension, single kidney, renal transplant, prior nephrectomy)
• Current use of nephrotoxic medications
• Recent acute illness with potential renal involvement
• Creatinine elevation or eGFR <60 mL/min/1.73 m2 on prior testing

Radiologist consultation prior to GBCA administration is required in patients with eGFR <30 mL/min/1.73 m2 [4]. For patients on dialysis, same-day dialysis following MRI is recommended where logistically feasible, irrespective of the GBCA group used [1].

8. Prior Contrast Agent Reaction History and Premedication Considerations

8.1 Incidence and Classification of Acute Hypersensitivity Reactions to GBCAs

Acute allergic-like (hypersensitivity) reactions to GBCAs are substantially less common than reactions to iodinated contrast agents. Allergic-like reactions occur in approximately 0.3-1.4% of GBCA administrations, are mostly mild, and severe reactions are rare at approximately 0.04% [8]. There is no cross-reactivity between different classes of contrast agents [4].

Prior reaction to a GBCA confers increased risk of reaction to subsequent GBCA administration. A history of atopy or asthma modestly increases the risk of allergic-like reactions, but restricting contrast use or premedicating solely on the basis of a history of asthma is not recommended by the ACR, given the modest and uncertain magnitude of this increased risk [4].

8.2 Premedication Protocols

Premedication (typically corticosteroid-based, with or without antihistamine addition) is used in patients with a documented prior moderate or severe reaction to a GBCA. The evidence base for premedication before GBCA administration is extrapolated from data collected in the context of iodinated contrast media; no randomised controlled trials exist specifically evaluating premedication efficacy before GBCA administration.

Direct risks of premedication are small and include transient leucocytosis, transient asymptomatic hyperglycaemia (20-80 mg/dL in non-diabetics; 100-150 mg/dL in diabetics), and a small risk of diphenhydramine-induced drowsiness (patients should not operate motor vehicles after diphenhydramine administration). The largest risk of premedication is indirect and related to the diagnostic delay imposed by the multi-hour corticosteroid premedication duration [4].

9. Anxiety, Claustrophobia, and Patient Psychological Preparation

9.1 Epidemiology and Clinical Impact

Anxiety attacks occur in as many as 2% of patients undergoing MRIs, with approximately 1% terminating the study early [13]. Claustrophobia in MRI arises from the combination of scanner bore confinement, acoustic noise from gradient coil switching, and the duration of the examination. Controllable air movement in the magnet bore, along with good patient communication and education, can help reduce these reactions [9,11].

Incomplete examinations due to claustrophobia or anxiety represent a significant quality and resource issue. Systematic pre-procedure screening for anxiety and claustrophobia, combined with targeted intervention, reduces examination failure rates and improves patient experience.

9.2 Systematic Screening and Intervention Strategies

Patients should be screened for claustrophobia and anxiety at the point of scheduling. The Claustrophobia Questionnaire (CLQ), a validated 26-item instrument, has been demonstrated to have predictive value for claustrophobic events during MRI and may be used as a formal screening tool in high-volume or research settings [7 — Enders J et al., Radiology 2011].

Non-pharmacological interventions with evidence of efficacy or clinical consensus support:

1. Detailed pre-procedure information provision: Patients who receive comprehensive written and verbal information about the MRI procedure experience reduced anxiety. Information should include anticipated duration, acoustic noise characteristics, the emergency alert system, and the ability to communicate with staff throughout the examination.
2. Patient positioning strategies: Feet-first entry into the magnet bore, where technically feasible for the anatomical region of interest, reduces subjective claustrophobic perception.
3. Bore ventilation and lighting: Air circulation within the bore and improved lighting reduce the sensation of confinement.
4. Music or audio: Evidence from observational studies supports the use of music or calming audio during the examination to reduce anxiety.
5. Companion presence: A trusted companion in the control room or, where facility design permits, within Zone IV, provides psychological reassurance.
6. Wide-bore MRI systems: Systems with bore diameters of 70 cm or greater and shorter bore lengths significantly reduce claustrophobic responses compared with standard 60 cm bore designs.
7. Virtual reality pre-familiarisation: Emerging evidence supports VR-based preparatory exposure as a method of reducing pre-procedure anxiety, particularly in paediatric and claustrophobic populations [8].

Pharmacological techniques for severe patient anxiety include anxiolytic medications such as benzodiazepines, warm blankets, panic buttons for immediate communication, and relaxation techniques including grounding, meditation, and deep breathing exercises. Open MRI systems or alternative imaging modalities represent the option of last resort for patients with refractory claustrophobia [13].

Patients receiving benzodiazepines for MRI-related anxiety must be accompanied by a responsible adult for transport and should be informed not to operate motor vehicles on the day of the examination. Paediatric sedation and general anaesthesia for MRI are specialised procedures requiring separate protocols addressing anaesthetic safety in the magnetic environment.

10. Fasting and Dietary Preparation

10.1 General Principles

Routine MRI examinations of the brain, spine, and musculoskeletal system do not require fasting in the absence of sedation, anaesthesia, or specific protocol requirements. The rationale for fasting where applicable relates to:

1. Reduction of aspiration risk in patients receiving sedation or general anaesthesia: fasting is mandatory in accordance with anaesthetic society guidelines (typically at least 6 hours for solids and 2 hours for clear fluids in adults).
2. Image quality optimisation for abdominal and pelvic studies: gastrointestinal peristalsis and luminal content can produce motion artefacts and reduce visualisation of adjacent structures.
3. Reduction of nausea risk associated with GBCA administration: this rationale is less clearly supported by current evidence. Recent observational data suggest that pre-procedure fasting does not significantly reduce the incidence of nausea or vomiting following GBCA administration; however, many institutional protocols continue to recommend 2-4 hours of fasting before contrast-enhanced MRI as a precautionary measure.

10.2 Protocol-Specific Fasting Requirements

The following summary reflects common institutional practices and is provided for orientation. Individual protocol-specific requirements supersede these general ranges and are specified in the corresponding child documents:

Examination Type                              | Typical Fasting  | Free Fluid

----------------------------------------------|------------------|---------------------------- Brain, spine, MSK (no sedation, no contrast) | None | None Brain, spine, MSK (with GBCA, no sedation) | None to 2 h | Water permitted Cardiac MRI (anatomical) | None | No caffeine 24h for stress Cardiac MRI (adenosine stress protocol) | 4 h | No caffeine 24h pre-exam Abdominal/pelvic MRI (with GBCA) | 4-6 h | Water permitted MRCP | 4-6 h | Water permitted MR Enterography | 4 h | Oral contrast prep 1-2h pre MRI with general anaesthesia/deep sedation | 6h solids/2h liq | Institution-specific

Patients with diabetes mellitus receiving insulin require special attention: fasting protocols must be coordinated with the treating endocrinologist or diabetologist to avoid hypoglycaemia. Blood glucose should be measured before the examination if fasting is required.

Water intake is generally encouraged in non-fasting patients scheduled for GBCA administration, as adequate hydration supports gadolinium renal clearance and reduces the theoretical risk of contrast nephropathy.

11. Medication Management

11.1 General Principles

Most medications should be continued as prescribed on the day of the MRI examination. There are no pharmacological interactions between standard medications and MRI electromagnetic fields. The relevant considerations are:

• Medications to be continued: Antihypertensives, antiepileptics, anticoagulants, thyroid medications, and most other chronic medications should be taken as usual. In fasting patients, medications may be taken with a small sip of water.

• Metformin: Although the risk of contrast-induced lactic acidosis with metformin is primarily established for iodinated contrast agents, some institutions apply similar precautionary hold guidelines to metformin in the context of GBCA-enhanced MRI in patients with renal impairment. Clinical judgement and institutional policy should guide this decision.

• Benzodiazepines or anxiolytics prescribed for MRI: These must be administered according to the prescribing physician's instructions, with appropriate monitoring during the examination and post-procedure discharge planning.

• Cardiac medications: For dedicated cardiac MRI examinations with stress protocols, specific medication restrictions apply and are detailed in the cardiac MRI-specific protocol.

12. Intravenous Access for Gadolinium-Based Contrast Administration

When GBCA administration is planned, intravenous access must be established prior to scanner entry. Standard peripheral venous cannulation with an appropriate gauge cannula (commonly 20-22 G for adults) is used. The choice of injection site should take into account the need for power injection where applicable: large calibre peripheral veins in the antecubital fossa or forearm are preferred.

The power injector-compatible cannula must be confirmed compatible with the planned injection rate; for dynamic contrast-enhanced sequences requiring rapid bolus injection (e.g., liver multiphasic, breast MRI, dynamic susceptibility contrast perfusion), injection rates of 2-5 mL/s are standard.

Extravasation risk must be assessed and managed. The incidence of GBCA extravasation is low (approximately 0.11% of injections), and most extravasations are mild and self- limiting; however, large extravasations into anatomically confined spaces (e.g., dorsum of the hand, orbit) may require intervention [1].

Patients with known difficult venous access should be flagged at the scheduling stage to allow for appropriate preparation (warm compresses, senior cannulation, or ultrasound- guided access).

13. Informed Consent and Patient Communication

13.1 Information Provision

All patients are entitled to receive clear, comprehensible information about the MRI procedure they are to undergo. This information should cover:

• The nature of the examination and its clinical purpose
• Duration and expected patient experience (noise, positioning, restricted movement)
• The emergency communication system (alarm squeeze device or verbal alert)
• Whether contrast will be administered, and if so, the associated risks
• Relevant preparation requirements (clothing, fasting if applicable, escort arrangement if sedation is planned)

Information should be provided in a format appropriate to the patient's language, literacy, and cognitive status. Pre-procedural information provision has been shown to reduce procedural anxiety and improve examination completion rates [8].

13.2 Consent for Contrast-Enhanced MRI

The standard for informed consent for GBCA administration varies by jurisdiction and institutional policy. In most settings, verbal consent following information provision is standard practice for routine GBCA administration in patients without significant contraindications. Written informed consent is required for:

• MRI with GBCA in pregnancy
• MRI with GBCA in patients with eGFR <30 mL/min/1.73 m2 when Group I agents are considered (Group II agents at all eGFR levels: the ACR states that informed consent prior to Group II GBCA injection is not recommended) [1]
• Research examinations

14. Special Populations: Summary of Additional Considerations

14.1 Paediatric Patients

Children generally require age-appropriate information and preparation strategies. Parental or guardian involvement is mandatory for patients below the age of consent. Young children often require sedation or general anaesthesia, triggering the full anaesthetic fasting and monitoring protocol. Specific considerations for paediatric body habitus (SAR management, RF coil sizing, patient immobilisation) are addressed in paediatric MRI protocols.

14.2 Patients with Reduced Mobility or Bariatric Patients

For patients with atypical habitus, including those with obesity, MRI safety evaluation requires particular attention to the assessment of bulk and focal heating by the radiofrequency field, as well as mechanical considerations related to patient positioning within the bore [2]. Table weight limits and bore aperture constraints must be verified before scheduling.

14.3 Patients with Communication or Cognitive Impairment

Patients who are unable to reliably complete the screening questionnaire, follow instructions during the examination, or operate the emergency alert device require tailored preparation, potentially including the use of sedation, the presence of a trained chaperone, or the use of alternative imaging modalities.

14.4 Detained Patients

In cases where a patient requires MRI while wearing RF-opaque metallic restraints (handcuffs, ankle cuffs), a request should be made that the patient be accompanied by the appropriate authorities who can and will remove the restraining device prior to the MR study and be charged with its replacement following the examination [1].

15. Documentation and Record-Keeping

Complete documentation of the pre-examination preparation process is both a safety and medicolegal requirement. Records should include:

• Completed MRI safety screening questionnaire (patient-completed and technologist- verified)
• Identity verification record
• Pregnancy status assessment for women of childbearing age
• Renal function results where GBCA administration is planned
• Allergy history and any premedication administered
• Consent documentation (verbal or written as appropriate)
• Record of all implants identified and their MRI safety status
• Name and signature of the MRI technologist who conducted the final screening verification

16. Emergency Preparedness in the MRI Environment

All MRI facilities must have documented and regularly rehearsed emergency protocols. Every clinical MRI unit must have immediate access to emergency equipment that is confirmed MR Safe or MR Conditional, including cardiac monitoring, defibrillation capabilities, and oxygen delivery systems with MR-compatible cylinders.

The most vital step in any medical or technical MRI emergency is promptly removing the patient from the scan room [9]. All personnel working in or entering the MRI environment must be familiar with the quench procedure, the location of emergency egress, and the procedure for calling emergency medical services.

Ferromagnetic projectile accidents have resulted in patient death. The use of non-MR- compatible ferromagnetic oxygen cylinders or other equipment as projectiles near Zone III/ IV remains a documented cause of fatal events [1,3].