For certain patients that undergo magnetic resonance (MR) examinations, the experience may be associated with emotional distress. Referring physicians, radiologists, and MRI technologists can best manage affected patients by understanding the etiology of the problem and knowing the appropriate maneuver or intervention to implement in order to counter-act the condition.
The experience of “psychological distress” in the MR environment includes all subjectively unpleasant experiences attributable to the procedure. Distress for the patient can range from mild anxiety that can be handled with simple reassurance, to a more serious panic attack that may require psychiatric intervention or medication. Severe psychological reactions to MR examinations are characterized by the rapid onset of at least four of the following: nausea, paresthesias, palpitations, chest pain, faintness, dyspnea, choking sensation, sweating, trembling, vertigo, depersonalization, and fear of losing control or dying.
Many symptoms of a panic attack mimic over-activity of the sympathetic nervous system, prompting concern that catecholamine responses may precipitate cardiac arrhythmias or ischemia in susceptible patients. However, to date, this has not been observed in the clinical MR setting. Nevertheless, for a medically unstable patient, it is advisable to have physiologic monitoring and support readily available.
In the mildest form, distress is the normal amount of anxiety that a person may experience when undergoing a diagnostic procedure. Moderate distress, severe enough to be described as a dysphoric psychological reaction, has been reported by as many as 65% of the patients examined by MR imaging. The most severe forms of psychological distress described by patients include anxiety, claustrophobia, or panic attacks.
Claustrophobia is a disorder characterized by the marked, persistent, and excessive fear of enclosed spaces. In such affected individuals, exposure to an enclosed space such as that found with certain MR systems, almost invariably provokes an immediate anxiety response that, in its most extreme form, is indistinguishable from the panic attack described above.
The actual incidence of distress in the MR environment is highly variable across studies due to differences in outcome measures used to describe this phenomenon. Some investigations indicated that as many as 20% of the individuals attempting to undergo MR procedures can’t complete the exams secondary to serious distress such as claustrophobia or other unwanted sensations. In contrast, other investigations have reported that as few as 0.7% of individuals have incomplete or failed MR procedures due to distress.
THE IMPACT OF EMOTIONAL DISTRESS
Patient distress can contribute to adverse outcomes for the MR procedure. These adverse outcomes include unintentional exacerbation of patient distress, a compromise in the quality and, thus, the diagnostic aspects of the imaging study and decreased efficiency of the MRI facility due to delayed, prematurely terminated, or cancelled studies. Patient compliance during an MR procedure, such as the ability to remain in the MR system and to hold still long enough to complete the study, is of paramount importance to achieve a diagnostically acceptable examination. If a good quality study can’t be obtained, the patient may require an invasive procedure in place of the inherently safer MR examination. Thus, for the distressed patient unable to undergo an MR procedure, there may be clinical, medico-legal, and economic related implications.
Increasing pressure to use MR system time efficiently to cover the costs of this expensive diagnostic imaging equipment puts greater stress on both staff and patients. The ability of referring physicians, radiologists, and MRI technologists to detect patient distress at the earliest possible time, to discover the source of the distress, and to provide appropriate intervention can greatly improve patient comfort, the quality of imaging, and efficiency of the facility.
FACTORS THAT CONTRIBUTE TO DISTRESS
Many factors contribute to distress experienced by certain patients undergoing MR procedures. Most commonly cited are concerns about the physical environment of the MR system. Also well documented is the anxiety associated with the underlying medical problem necessitating the MR examination. Certain individuals, such as those with psychiatric illnesses, may be predisposed to suffer greater distress.
The physical environment of the MR system is clearly one important source of distress. Sensations of apprehension, tension, worry, claustrophobia, anxiety, fear, and panic attacks have been directly attributed to the confining dimensions of the MR system. For example, for some scanners, the patient’s “line of sight” may be three to ten inches from the inside of the MR system, prompting feelings of uncontrolled confinement and detachment.
Similar distressing sensations have been attributed to other aspects of the MR environment including the prolonged duration of the examination, the acoustic noise, the temperature and humidity within the MR system, and the stress related to restriction of movement. Additionally, being inside of the scanner may produce a feeling of sensory deprivation, which is also known to be a precursor of anxiety states.
Adverse psychological reactions are sometimes associated with MR procedures simply because the examination may be perceived by the patient as a “dramatic” medical test with an associated uncertainty of outcome, such that there may be fear of the presence of disease or other condition. In fact, any type of diagnostic procedure can produce anxiety for the patient.
MR systems that have an architecture that utilizes a vertical magnetic field offer a more open design that is presumed to reduce the frequency of distress associated with MR procedures. The latest versions of these “open” MR systems, despite having static magnetic field strengths of 0.3-Tesla or lower, have improved technology (i.e., faster gradient fields, optimized surface coils, etc.) that permit acceptable image quality for most types of standard, diagnostic imaging procedures. The latest generation of high-field-strength (1.5-Tesla and 3-Tesla) MR systems have shorter and wider bore configurations that likely mitigate feelings of being enclosed or being overly confined. In fact, Hunt et al. (2011) reported that the use of a 1.5-Tesla, wide-short-bore scanner increased the examination success rate in patients with claustrophobia and substantially reduced the need for anesthesia-assisted MRI examinations, even when claustrophobia was severe. However, Enders et al. (2011) indicated that there was not substantial difference between claustrophobia in patients undergoing MRI using a short-bore versus an open, MR system.
In 1993, a specially designed, low-field-strength (0.2-Tesla) MR system (Artoscan, Lunar Corporation/General Electric Medical Systems, Madison, WI and Esaote, Genoa, Italy) became commercially available for MR imaging of extremities. The use of this dedicated extremity MR system provides an accurate, reliable, and relatively inexpensive means (i.e., in comparison to the use of a whole-body MR system) of evaluating musculoskeletal abnormalities. In fact, the utilization of this extremity MR system to assess musculoskeletal pathology is an acceptable alternative to whole-body MR systems since the diagnostic capabilities for evaluation of the knee, shoulder, and other extremities has been reported to be comparable to mid- or high-field-strength MR systems.
The architecture of the extremity MR system has no confining features or other aspects that would typically create patient-related problems. This is because only the body part that requires imaging is placed inside the bore of the magnet during the MR examination. One research study reported that 100% of the MR examinations that were initiated were completed without being interrupted or cancelled for patient-related problems. The unique design of the extremity MR system is believed to have contributed to the successful completion of the MR procedures in the patients of this study.
Patients with pre-existing psychiatric disorders may be at greater risk for experiencing distress in the MR environment. Accordingly, patients with pre-existing conditions should be identified prior to MR examinations to implement anxiety-minimizing efforts (see below). Patients with other psychiatric illnesses such as depression and any illness complicated by thought dysfunction, such as schizophrenia or manic-depressive disorder, may also be at increased risk for distress in the MR environment.
Patients with psychiatric illnesses may, under normal circumstances, be able to tolerate the MR environment without a problem, as is clear from the thousands of subjects who participate in clinical neuroimaging and functional MRI research studies each year. However, the increased stress due to their medical illness or fear of medical illness can exacerbate their psychiatric symptoms to such an extent that they may have difficulty complying with MR procedures.
TECHNIQUES TO MINIMIZE PATIENT DISTRESS
Various procedures exist to minimize distress or anxiety in patients undergoing MR procedures (Table 1). Some measures should be employed for all examinations, while others may be required only if the patient experiences distress due to the factors described above.
Table 1. Techniques to manage patients with distress associated with MR procedures.
1) Prepare and educate the patient concerning specific aspects of the MR procedure (e.g., MR system dimensions, gradient noise, intercom system, constant presence of the MRI technologist, etc.).
2) Allow an appropriately screened relative or friend to remain with the patient during the MR examination.
3) Maintain verbal, visual, and/or physical contact with the patient during the MR procedure.
4) Use an appropriate stereo system to provide music to the patient.
5) Use an appropriate video monitor or goggles to provide a visual distraction to the patient.
6) Use a virtual reality environment system to provide audio and visual distraction.
7) Place the patient prone for the examination.
8) Position the patient feet-first instead of head-first into the MR system.
9) Use mirrors or prism glasses to redirect the patient’s line of sight.
10) Use a blindfold so that the patient is not aware of the surroundings.
11) Use bright lights inside of the MR system.
12) Use a fan inside of the MR system.
13) Use vanilla scented oil or other aroma therapy.
14) Use relaxation techniques such as controlled breathing or mental imagery.
15) Use systematic desensitization.
16) Use medical hypnosis.
17) Use a sedative or other similar medication.
For All Patients Undergoing MR Procedures
Referring clinicians should take time to explain the reason for the MR procedure and what he/she expects to learn from the results with respect to the implications for treatment and prognosis. The single most important step is to educate the patient about the aspects of the MR examination that may be challenging or difficult. This includes conveying, in terms that are understandable to the patient, the internal dimensions of the MR system, the level of gradient magnetic field-induced acoustic noise to expect, and the estimated time duration of the examination.
Studies have documented a decrease in the incidence of premature termination of MR examinations when patients were provided with detailed information about the procedures. Accordingly, patients should be provided with an appropriate brochure or video presentation supplemented by a question and answer session with an MR-trained healthcare professional prior to the examination.
Many details of patient positioning in the MR system can increase comfort and, thus, minimize distress. Taking time to ensure comfortable positioning with sufficient padding and blankets to alleviate undue discomfort or pain is also important. Adequate ear protection should be provided routinely to decrease acoustic noise from the MR system, as needed (i.e., this is typically not required for low-field-strength MR scanners). Demonstration of the two-way intercom system, “squeeze ball”, or other monitoring technique to reassure the patient that the MR staff is readily available during the examination is vital for proper patient management.
For Mildly-to-Moderately Distressed Patients
If a patient continues to experience distress after the afore-mentioned measures are implemented, additional interventions are required. Frequently, all that is necessary to successfully complete an MR examination is to allow an appropriately screened relative or friend to remain with the patient. A familiar person in the MR system room will often help an anxious patient develop an increased sense of security. If a supportive companion is not present, a staff member can maintain contact with the patient during the examination to decrease psychological distress.
Placing the patient prone so that the opening of the MR system can be seen will provide a sensation of being in a device that is more spacious. As such, prone positioning can alleviate the “closed-in” feelings frequently associated with being supine. Unfortunately, prone positioning may not be practical or appropriate if the patient has certain underlying medical conditions (e.g., shortness of breath, the presence of chest tubes, wearing a cervical fixation device, etc.). Another method of positioning the patient that may help is to place the individual feet-first instead of head-first into the scanner.
Mirrors or prism glasses can be used to permit the patient to maintain a vertical view of the outside of the MR system in order to minimize phobic responses. Using a blindfold or “eye pillow” (e.g., small pillow containing flax seeds) so that the patient is unaware of the close surroundings has also been suggested to be an effective technique for enabling anxious patients to successfully undergo MR procedures.
The environment of the MR system may be changed to optimize the management of apprehensive patients. For example, the presence of higher lighting levels tends to make most individuals feel less anxious. Therefore, the use of bright lights at either end and inside of the MR system can produce a less imposing environment for the patient. Using a fan inside of the scanner to increase airflow will also help reduce the sensation of confinement. In addition, aroma therapy (e.g., placing a cotton pad moistened with a few drops of lemon, vanilla, or cucumber oil in the MR system) can help reduce distress by providing the patient with a pleasant, olfactory stimulation.
Specialized systems that transmit music or audio communication through headphones have been developed specifically for use with MR systems. Reports have indicated that these devices successfully reduced symptoms of anxiety in patients during MR procedures. Furthermore, it is possible to provide visual stimulation to the patient via monitors or special goggles. Use of visual stimuli to distract patients tends to reduce distress. Finally, a system may be used to provide a calming virtual reality environment for the patient that may likewise serve as an acceptable means of audio and visual distraction from the MR procedure (this device is frequently used for functional MRI studies).
For Severely Distressed or Claustrophobic Patients
Patients who are at high risk for severe distress in the MR environment and can be identified as such by their referring clinician or by the scheduling MR staff person should be offered the opportunity to have pre-MR procedure behavioral therapy. MR procedures conducted in patients that previously refused or were unable to tolerate the MR environment have been reported to be successfully managed using relaxation techniques, systematic desensitization, and medical hypnosis.
In the majority of MRI facilities, patients severely affected by claustrophobia, anxiety, or panic attacks in response to MR procedures usually need sedation when attempts to counteract their distress fail. Using a short-acting sedative or an anxiolytic medication may be the only means of managing a patient with a high degree of anxiety. However, the use of sedatives in patients prior to and during MR procedures may not be required in all instances, nor is it always practical.
Importantly, the use of sedation in the MR environment requires special preparation involving several important patient management considerations. For example, the time when the patient is administered the medication for optimal effect prior to the examination must be considered along with the possibility that an adverse reaction may occur. The use of acceptable monitoring equipment operated by appropriately trained and experienced healthcare professionals is required to ensure patient safety. In addition, provisions should be available for an area to permit adequate recovery of the patient after an MR procedure that involves sedation.
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