Patient Distraction and Entertainment System for Magnetic

Resonance Imaging using Visual Effects Synchronized to the

Scanner Acoustic Noise

Refaat E. Gabr and Ponnada A. Narayana

The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, U.S.A.

Keywords: Patient Distraction, Magnetic Resonance, Gradient Coils, Acoustic Noise, Entertainment, Visualization,

Multisensory.

Abstract: Acoustic noise is a major source of discomfort for patients undergoing magnetic resonance imaging (MRI)

examination. Loud noise is generated from fast gradient switching during MRI scanning. The noise level is

reduced by wearing hearing protection devices, but the noise cannot be entirely avoided. Patient distraction

techniques can shift the attention away from the annoying noise. We implemented a simple and low-cost

system for patient distraction using visual effects that are synchronized to the gradient acoustic noise. This

multisensory approach for patient distraction is implemented on a 3.0T scanner and tested in six healthy

adult volunteers. After the scan was completed, the volunteers were asked about their scan experience with

visualization, rating their preference on a 0-10 scale. The images were visual inspected for any artifacts. All

volunteers indicated improved experience with the proposed visualization system with an average score of

6.3. The image quality was not affected by visualization.

1 INTRODUCTION

Magnetic resonance imaging (MRI) is a powerful

diagnostic technique, with approximately 60 million

scans performed worldwide each year (Sutton et al.,

2008). MRI provides excellent soft tissue contrast

without using ionizing radiation, making it a

preferred technique among many patient

populations, including children. Unfortunately, the

MRI environment suffers from multiple factors that

make it less patient friendly. These include the

confined environment inside the magnet bore and

the loud acoustic noise generated by the scanner.

Acoustic noise in MRI arises from the rapid

alterations in the current flowing in the gradient

coils when executing an imaging protocol. The large

currents in the presence of the strong magnetic field

produce large Lorentz forces, which cause the

vibrations of the gradient coils. The vibrations

generate loud tapping, knocking, or chirping sounds

(McJury and Shellock, 2000).

Acoustic noise can reach dangerous levels, with

the sound pressure level exceeding 100 dB(A)

(Counter et al., 2000; Price et al., 2001), where the

units dB(A) account for the frequency-dependence

of the human ear. Earplugs, headphones, and active

noise cancellation (McJury et al., 1997) can

significantly reduce the noise level and improve

hearing protection and patient safety (Brummett et

al., 1988). However, acoustic noise is not completely

avoidable, and noise remains a factor that adversely

affects the patient experience in MRI (McNulty and

McNulty, 2009).

A recent approach to reduce the perceived noise

it to play the gradient pulses in a fashion that

produces music (Ma et al., 2015). This approach can

improve the patient experience, but requires special

programming requirements to change the way MRI

pulse sequences are performed. This is beyond the

reach of most MRI centres.

The loud noise of MRI represents an intense

auditory stimulus. However, the intensity of a

sensory stimulus is one of multiple factors that

determine the tolerance of that stimulus. The

perception of the stimulus also depends on the

presence of other stimuli in the environment, and on

the multisensory integration capabilities of the brain

(Macaluso and Driver, 2005; Shimojo and Shams,

2001; Stein et al.. 2009; Witten and Knudsen, 2005).

Hence, the perception of the loud noise of MRI can

Gabr, R. and Narayana, P.

Patient Distraction and Entertainment System for Magnetic Resonance Imaging using Visual Effects Synchronized to the Scanner Acoustic Noise.

DOI: 10.5220/0005680503190323

In Proceedings of the 11th Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISIGRAPP 2016) - Volume 3: VISAPP, pages 319-323

ISBN: 978-989-758-175-5

319

be modulated by the introduction of other sensory

inputs (Gillies et al., 2013). Multisensory studies

suggest that vision dominates our sensory input and

can bias the perception of other stimuli (Witten and

Knudsen, 2005). We investigated whether visual

effects in the form of animated graphics that are

synchronized with the scanner acoustic noise could

change the patient’s perception of the loud noise of

the scanner. Moreover, by using pleasing and

engaging visual effects, this approach may provide

an entertaining environment that could further

improve the patient comfort and experience.

In this paper we describe the implementation of a

novel, simple, low-cost, and practical patient

distraction system based on audio-visual integration,

and demonstrate its performance in a clinical MRI

system.

2 METHODS

2.1 System Setup

All developments were carried out on a 3.0 T Philips

Ingenia MRI system (Philips Healthcare, Best, The

Netherlands). Figure 1 shows the schematic of the

patient distraction and entertainment setup.

A sensitive microphone is placed in the MRI

operator room adjacent to the MRI examination

room. The MRI scanner’s noise is picked up by the

microphone and is fed as the input audio signal to a

music player with sound-modulated visualization

capabilities. The visualization is projected back to a

display monitor placed at one end of the scanner

magnet. The display is projected to the patient eyes

using a system of mirrors mounted on top of the

head coil. MRI-compatible goggles, if available, can

be used in place of the display monitor and the

mirrors.

The Winamp media player software v5.666

(Nullsoft Inc., available at www.winamp.com) was

used to play the input noise signal from the

microphone. Other players with comparable

functionality can be similarly used. Winamp

includes multiple visualization plugins, including

MilkDrop 2 (www.geisswerks.com/milkdrop),

which was used in all experiments in this work.

MilkDrop is a hardware-accelerated environment for

running visualization routines (called presets)

defined by a scripting language.

A large number of visualization routines are

available in MilkDrop. However, not all routines are

suitable for use with patients. Based on

experimentation we identified the following criteria

for an MRI-friendly visualization routine. First, the

visualization routine must be reasonably responsive

to the audio signal such that the patient can easily

associate the animation with the acoustic noise.

Second, the routine must use an eye-friendly color

scheme, avoiding very bright colors. Third, the

routine should avoid very rapid transitions. Finally,

the routine should contain entertaining animations

that engage the patient. Based on a consensus of the

authors and two MRI technologists, the visualization

routine selected in this work was the “Flexi, martin

+ geiss - dedicated to the sherwin maxawow”. This

preset displays a two-dimensional color-changing

flowing pattern which is modulated by the input

audio signal. This preset satisfied all the four criteria

we identified for a patient-friendly visualization

routine (Fig. 2).

Figure 1: The MRI acoustic noise-synchronized

visualization system. The mirror mounted on the head coil

helps the patient to view the display.

2.2 MRI Experiments

Six healthy adult volunteers (5 males, 1 female, age

= 42±13 years) participated in this study. The

volunteers were told that they will be watching

video material during the scan, but no clue was

provided about how the visualization worked or that

it was triggered by sound.

All six subjects were scanned twice using the

same protocol but with the visualization feedback

used in only one imaging session. Imaging in the

two sessions used a routine MRI brain protocol

including a survey scan, field calibration scan,

diffusion weighted imaging (DWI), three-

dimensional magnetization-prepared T1-weighted

(3D T1), multi-slice dual-echo turbo spin echo (2D

TSE) and multi-slice fluid-attenuated inversion

recovery (2D FLAIR) pulse sequences. These scans

VISAPP 2016 - International Conference on Computer Vision Theory and Applications

320

are typically used in routine clinical examination.

The total scan time for each imaging session was

~16 min. Note that the intensity and the pattern of

the scanner noise directly depend on the type of the

pulse sequence used and its scan parameters. The

scan parameters of all pulse sequences are listed in

Table 1.

Immediately after the imaging study, the

volunteers were asked whether they prefer the scan

with or without visualization, and were asked to rate

their preference on a scale from 0 to 10, with 0 being

no preference for either options (with or without

visualization), and 10 being highest preference. To

reduce possible bias on scoring, half of the subjects

underwent the visualization experiment in the first

part of the study, while the other half had the

visualization in the second part of the scan.

To investigate whether the visualization

feedback could increase the degree of volunteer

involuntary motion, corresponding image sets in the

two sessions were compared side-by-side for any

possible motion artifacts.

Table 1: The MRI protocol and the scan parameters used

in the study. GRE, gradient-recalled echo; SE, spin echo;

EPI, echo planar imaging; FOV, field-of-view; TR,

repetition time; TE, echo time; TI, inversion time.

Protocol

Survey

DWI

3D T1 2D TSE 2D FLAIR

Sequence

type

GRE

SE +

EPI

GRE SE SE

TR / TE

[ms]

11 / 4.6

5807 /

8.0 /

3.7

6800 /

(9.5, 90)

10,000 / 80

TI [ms] 800 NA 1068 NA 2600

Flip angle

[°]

15 90 6 90 90

FOV [mm] 300 x 300

240 x

240

256 x

256

256 x

256

256 x 256

Slice

Thickness

[mm]

10 3 1 3 3

Matrix 308 x 128

200 x

118

256 x

256

256 x

208

256 x 238

Plane 3-plane Axial Sagittal Axial Axial

Pulse train

length

64 59 256 12 16

b-value

[s/mm

]

NA 1000 NA NA NA

Scan time

[min:sec]

0:31 2:02 5:05 3:24 4:20

3 RESULTS

Figure 2 shows screenshots taken from the

visualization preset while playing out an MRI pulse

sequence. The visualization provided a sound-

responsive modulation of the flow pattern that is

pleasant for the observer. Table 2 lists the preference

and the scores reported by the six volunteers. All

volunteers preferred visualization, with average

score 6.3±1.2.

The images acquired in the two sessions (with

and without running the visualization) showed no

noticeable differences, indicating that the

visualization feedback did not affect the image

quality (Fig. 3). In one subject, motion artifacts were

observed on the dual echo scan as a result of patient

coughing in the middle of the scan. The scan was not

repeated.

Figure 2: Screenshots of the MRI acoustic noise-

synchronized visualization at four moments during the

execution of a T1 pulse sequence. The first two images

(a,b) are from a quiet period in the sequence, while the last

two (c,d) are recorded at a gradient-intensive period.

Table 2: Scores given by the volunteers for their scan

preference. 0=no preference, 10=most preference.

Volunteer Prefer Visualization? (Yes/No)

Score

[0-10]

1 Yes 7

2 Yes 5

3 Yes 8

4 Yes 5

5 Yes 7

6 Yes 6

All

6.3 ± 1.2

4 DISCUSSION

The high preference score reported by the volunteers

for the visualization indicates that visual effects

synchronized to the scanner’s acoustic noise

Patient Distraction and Entertainment System for Magnetic Resonance Imaging using Visual Effects Synchronized to the Scanner Acoustic

Noise

321

improved the patient experience during MRI

examination. All volunteers indicated that they were

entertained by the visualization. One volunteer

indicated that the visualization kept him awake

during the study when in fact he preferred to take a

nap. This case demonstrates that the visualization

may not be suitable for all subjects and that it is

better suited for certain categories of patients. This

approach for patient distraction and entertainment

may be particularly beneficial for scanning children.

Figure 3: MRI images acquired from one volunteer with

and without the visualization. No differences in image

quality are observed between the two datasets.

All experiments were performed with a single

visualization routine for the relatively short 16-min

scan. Nevertheless, one volunteer expressed that

after approximately five minutes the visualization

scheme was not as entertaining as it was at the

beginning of the study. Multiple and interleaved

routines should thus be incorporated and cycled

through in the visualization program to prevent

boredom from longer scans.

Very bright colors or rapid animations

corresponding to periods of fast-switching gradients

may be startling to the patient and cause involuntary

motion. We did not notice any effect on the image

quality from turning on the visualization routine

used in this preliminary study. A larger study is

recommended to study the effect of this technology

on patient motion with different types of

visualization routines.

The developed system for patient distraction and

entertainment in MRI is a simple, low-cost (costs

only the price of a sensitive microphone), and easy

to build around any MRI system without the need

for specialized pulse sequences. MRI-compatible

display monitors or goggles are required in this

approach. However, MRI-compatible display

monitors are widely available in many MRI suites as

they are needed for functional MRI studies.

We anticipate that optimized or even patient-

customized visualization routines may further

improve the patient experience and reduce the level

of anxiety associated with MRI procedures. These

possibilities will be explored in future studies.

ACKNOWLEDGEMENTS

This work was supported by a CTSA grant from the

National Center for Advancing Translational

Sciences of the National Institutes of Health under

Award Number UL1TR000371, awarded to The

University of Texas Health Science Center at

Houston, and the Chair in Biomedical Engineering

Endowment Funds.

The authors thank Vipulkumar Patel and Corina

Donohue for valuable technical assistance in

conducting the MRI experiments.

REFERENCES

Brummett, R. E., J. M. Talbot, and P. Charuhas. 1988.

“Potential Hearing Loss Resulting from MR Imaging.”

Radiology 169(2):539–40.

Counter, S. A. et al. 2000. “Analysis of Magnetic

Resonance Imaging Acoustic Noise Generated by a

4.7 T Experimental System.” Acta oto-laryngologica

120(6):739–43.

Gillies, Murray Fulton, Raymond Van Ee, Van Elswijk,

Gijs Antonius Franciscus, and Tim Johannes Willem

VISAPP 2016 - International Conference on Computer Vision Theory and Applications

322

Tijs. 2013. “System and Method for Distraction of

Patient During Scanning.” U.S. Patent Application

13/988,538.

Ma, Dan et al. 2015. “Music-Based Magnetic Resonance

Fingerprinting to Improve Patient Comfort during

MRI Examinations.” Magnetic Resonance in Medicine

doi: 10.1002/mrm.25818. [Epub ahead of print].

Macaluso, Emiliano, and Jon Driver. 2005. “Multisensory

Spatial Interactions: A Window onto Functional

Integration in the Human Brain.” Trends in

Neurosciences 28(5):264–71.

McJury, M., R. W. Stewart, D. Crawford, and E. Toma.

1997. “The Use of Active Noise Control (ANC) to

Reduce Acoustic Noise Generated during MRI

Scanning: Some Initial Results.” Magnetic Resonance

Imaging 15(3):319–22.

McJury, Mark, and Frank G. Shellock. 2000. “Auditory

Noise Associated with MR Procedures: A Review.”

Journal of Magnetic Resonance Imaging 12(1):37–45.

McNulty, J. P., and S. McNulty. 2009. “Acoustic Noise in

Magnetic Resonance Imaging: An Ongoing Issue.”

Radiography 15(4):320–26.

Price, David L., Janet P. De Wilde, Annie M. Papadaki,

Jane S. Curran, and Richard I. Kitney. 2001.

“Investigation of Acoustic Noise on 15 MRI Scanners

from 0.2 T to 3 T.” Journal of Magnetic Resonance

Imaging 13(2):288–93.

Shimojo, S., and L. Shams. 2001. “Sensory Modalities Are

Not Separate Modalities: Plasticity and Interactions.”

Current Opinion in Neurobiology 11(4):505–9.

Stein, Barry E., Terrence R. Stanford, and Benjamin A.

Rowland. 2009. “The Neural Basis of Multisensory

Integration in the Midbrain: Its Organization and

Maturation.” Hearing Research 258(1-2):4–15.

Sutton, Richard et al. 2008. “Safety of Magnetic

Resonance Imaging of Patients with a New Medtronic

EnRhythm MRI SureScan Pacing System: Clinical

Study Design.” Trials 9:68.

Witten, Ilana B., and Eric I. Knudsen. 2005. “Why Seeing

Is Believing: Merging Auditory and Visual Worlds.”

Neuron 48(3):489–96.

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Noise

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