Purpose
To evaluate whether MR scanners with acoustic noise reduction and a short magnetic bore reduce the rate of claustrophobic reactions.

Materials and Methods
We performed a cohort study in an outpatient setting, enrolling a total of 55,734 consecutive patients referred for MRI of any part of the body based on a clinical indication. Imaging was performed using a conventional MR scanner (42,998 patients) and a recently developed MR scanner (12,736 patients) with 97% acoustic noise reduction and a short bore. Multiple logistic regression analysis was used to adjust for the nonrandomized design.

Results
In addition to those undergoing head-first examinations, female and middle-aged patients were significantly more likely to develop claustrophobia in the logistic regression analysis (P < 0.001). The rate of claustrophobic reactions was significantly lower with the recent MR scanner (0.7%; 95% confidence interval [CI]: 0.6–0.9%) than with the conventional scanner (2.1%; 95% CI, 2.0–2.3%; P < 0.001) with an adjusted odds ratio (OR) of 3.1 (95% CI, 2.5–3.9) and a number needed to treat of 72 (95% CI, 63–85).

Conclusion
The incidence of claustrophobia may be reduced by a factor of 3 when recently-developed MR scanners are used. J. Magn. Reson. Imaging 2007;26:1322–1327. © 2007 Wiley-Liss, Inc.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/jmri.21147

Claustrophobia during magnetic resonance imaging: Cohort study in over 55,000 patients

Our study results suggest that there may be a large group of women at elevated risk of breast cancer for whom MR imaging would not be acceptable; for these women, supplemental screening with US combined with mammography could be considered.

Reasons women at elevated risk of breast cancer refuse breast MR imaging screening: ACRIN 6666.

Purpose
To evaluate the incidence of MRI-related claustrophobia and prematurely terminated MRI (ptMRI) examinations due to claustrophobia in a large-scale cohort study.

Materials and Methods
The hospital's computerized radiology information system (RIS) was retrospectively analyzed for all 1.5-Tesla MRI examinations and reports during the year 2004. Data collected included demographic information, body part examined, known claustrophobia, and whether the examination was prematurely terminated. All information available on the MRI examinations and the patient-based data (i.e., excluding any additional examinations per patient) were analyzed.

Results
A total of 5798 MRI reports of 4821 patients were evaluated. A total of 95 patients (1.97%) suffered from claustrophobia and 59 (1.22%) prematurely terminated the examination due to claustrophobia. The incidence of ptMRI was higher in women than men (no statistical significance). The majority of patients with ptMRI were between 20 and 80 years old. Patients undergoing head MRI showed the highest incidence of ptMRI and those undergoing extremity, breast, or pelvic MRI had the lowest. Prone compared to supine positioning results in the lowest ptMRI incidence (P < 0.05).

Conclusion
Claustrophobic reactions cause a relatively low incidence of ptMRI and are influenced by sex, body part examined, and positioning within the MR scanner. Sedation and prone positioning might help overcome these reactions. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/jmri.21012

Claustrophobia and Premature Termination of Magnetic Resonance Imaging Examinations

Objectives: To assess organisational and patient specific limitations and safety of magnetic resonance imaging (MRI) as the first line investigation for hospital admitted stroke patients. 

Methods: Consecutive patients admitted with acute stroke were assessed and an attempt was made to perform MRI in all patients. Oxygen saturation and interventions required during scanning were recorded. 

Results: Among 136 patients recruited over 34 weeks, 85 (62%) underwent MRI. The patients' medical instability (15 of the 53 not scanned), contraindications to MRI (six of the 53 not scanned), and rapid symptom resolution (10 of the 53 not scanned) were the main reasons for not performing MRI. Of the 85 patients who underwent MRI, 26 required physical intervention, 17 did not complete scanning, and 11 of the 61 who had successful oxygen saturation monitoring were hypoxic during MRI. Organisational limitations accounted for only 13% of failures to scan. 

Conclusions: Up to 85% of hospital admitted acute stroke patients could have MRI as first line imaging investigation, but medical instability is the major limitation. Hypoxia is frequent in MRI. Patients should be monitored carefully, possibly by an experienced clinician, during scanning.

https://jnnp.bmj.com/content/jnnp/76/11/1525.full.pdf

Magnetic resonance brain imaging in patients with acute stroke: feasibility and patient related difficulties

The issues involved with recording vital functions in the magnetic resonance imaging (MRI) environment using fiber-optic sensors are considered in this paper. Basic physiological parameters, such as respiration and heart rate, are fundamental for predicting the risk of anxiety, panic, and claustrophobic episodes in patients undergoing MRI examinations. Electronic transducers are generally hazardous to the patient and are prone to erroneous operation in heavily electromagnetically penetrated MRI environments; however, nonmetallic fiber-optic sensors are inherently immune to electromagnetic effects and will be crucial for acquiring the above-mentioned physiological parameters. Forty-seven MRI-tested or potentially MRI-compatible sensors have appeared in the literature over the last 20 years. The author classifies these sensors into several categories and subcategories, depending on the sensing element placement, method of application, and measure and type. The author includes five in-house-designed fiber Bragg grating based sensors and shares experience in acquiring physiological measurements during MRI scans. This paper aims to systematize the knowledge of fiber-optic techniques for recording life functions and to indicate the current directions of development in this area.

https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-20/issue-1/010901/Fiber-optic-sensors-for-monitoring-patient-physiological-parameters--a/10.1117/1.JBO.20.1.010901.pdf

Fiber-optic sensors for monitoring patient physiological parameters: a review of applicable technologies and relevance to use during magnetic resonance imaging procedures

A recognized cause of incomplete or cancelled MRI examinations is anxiety and claustrophobic symptoms in patients undergoing MR scanning. This appears to be a problem in many MRI centres in Western Europe and North America, where it is said to be costly in terms of loss of valuable scan time, and has led to researchers suggesting several anxiety-reducing approaches for MRI. To determine the incidence of failed MRI examination among our patients and if there are any associations with a patient's sex, age and education level, we studied claustrophobia that led to premature termination of the MRI examination in the University Malaya Medical Centre (UMMC) in 3324 patients over 28 months. The incidence of failed MRI examinations due to claustrophobia in the UMMC was found to be only 0.54%. There are associations between claustrophobia in MRI with the patients' sex, age and level of education. The majority of those affected were male patients and young patients in the 25-45-years age group. The patients' education level appears to be the strongest association with failed MRI examinations due to claustrophobia, where the majority of the affected were highly educated individuals. Claustrophobia in MRI is more of a problem among the educated individuals or patients from a higher socio-economic group, which may explain the higher incidence in Western European and North American patients.

P Narayanan

Papers

Failed magnetic resonance imaging examinations due to claustrophobia.