Mascara—an unsuspected cause of magnetic resonance imaging artifact

Magnetic Resonance Imaging. Vol 3, pp. 287-289. Printed in the USA. All rights reserved.

1985

073&725X/8533.00 + .OO Copyright 0 1985 Pergamon Press Ltd.

l Case Report MASCARA-AN

UNSUSPECTED CAUSE OF MAGNETIC IMAGING ARTIFACT FRANCIS

W.

SMITH AND GORDON

A.

RESONANCE

CROSHER

Department of Nuclear Medicine, Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB9 2ZB, Scotland It is well recognised that metals, especially iron, will cause artifacts in magnetic resonance (MR) images. Hitherto it has not been recognised that some facial cosmetics contain magnetic materials, in sufficient quantities to cause artifacts. We report a case of a 25-year-old female who had MR images of her orbits made while wearing mascara eye makeup. The resultant images showed distortion of the signal over the anterior aspect of both eyes. Examination following the removal of the eye makeup resulted in the acquisition of normal images. The typical ingredients of mascara are natural and synthetic waxes, glycerine, water, kaolin, preservatives, polymer film formers and pigments. A wide range of pigments may be used, especially iron oxide, which is a constituent of both brown and blue mascara. In addition it is likely that a number of mascaras will be contaminated with heavy metals. As a result of this observation we now ensure that all patients who are undergoing MR imaging of the head, remove all facial cosmetics as well as any jewelry prior to imaging.

INTRODUCTION

.

employed consists of readout pulses every 1000 msec with alternate readout pulses preceded by inversion. The inversion is accomplished by adiabatic fast passage with a continuous delay of 200 msec. In other words, the pulse sequence consists of interleaved saturation recovery (S,) and inversion recovery (S,) pulses ( TR = 1000 msec; T, = 200 msec).‘*’ After acquisition the data may be displayed as either proton density, inversion recovery or calculated T, images on a greyscale Visual Display Unit. T, is calculated for each element from the formula

It is well recognised that the presence of metal objects either on or in a patient being imaged using magnetic resonance is a potential source of artifact in the final image. It is for this reason that patients are asked to remove any jewelry prior to imaging. No reports of the effect of some facial cosmetics on MR images have been found and until the case described below came to our attention we were unaware that they may cause image artifacts. CASE REPORT

T, = 200/ln

A 25-year-old female presented with a 2 week history of “seeing a shadow” in front of her right eye. Examination revealed slight engorgement of the retinal veins of the right eye and a small temporal field visual defect. She was referred for MRI to exclude an orbital lesion, central vasculitis or a pituitary tumor and was examined as an outpatient. Images were made using the Aberdeen University built magnetic resonance imager. This imager is based on a four-coil, air-cored, resistive magnet of 0.08 T which gives a resultant resonant frequency of 3.4 MHz for hydrogen protons. Data for each section, which may be either sagittal, corona1 or axial, are collected in 256 set by the spin-warp method. The pulse sequence

[2S,/(S,

- S,)].

The initial image made through the orbit demonstrated an absence of signal from the eyelids and anterior aspect of both eyes in both the proton density and calculated T, images (Fig. 1). The posterior aspects of both globes and the retro-bulbar part of the orbits were clearly demonstrated. The patient was removed from the imager and examined. She was found to be wearing both eyeshadow and mascara. After removal of these cosmetics further images were made which were free from artifact and demonstrated no significant abnormality (Fig. 2). It was therefore assumed that the eye makeup had

Acknowledgments-We

Pharmacy Department, Aberdeen Royal Infirmary for their help in ascertaining the constituents of mascara and other eye cosmetics.

wish to thank Professor J. R. Mallard and Dr. J. M. S. Hutchison for the development and use of the Aberdeen University NMR imager and the staff of the 287

Magnetic Resonance Imaging 0 Volume 3, Number 3, 1985

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Fig. 1. (a) Proton density. (b) T, axial images of the orbits of a patient wearing mascara. Absence of signal from the eyelids and anterior aspect of the eye is

recognised. been responsible for causing the artifact. To demonstrate that this was the case, an image of our 20cm-diam, copper sulphate-containing phantom was made after 1 cm’ areas of the patient’s mascara and other eye cosmetics had been applied to it. This image demonstrated a large artifact where the mascara had been applied and a smaller one where one of eyeshadows had been applied (Fig. 3). Three other eyeshadow preparations had also been applied but they did not cause any artifact. The one causing the artifact had a

Fig. 2. (a) Proton density. (b) T, images of the same patient following removal of the mascara. The eyelids and anterior aspect of the eye appear normal.

Fig. 3. Proton density image of a circular phantom on which five different eye cosmetics had been placed. The mascara responsible for the image artifact shown in Fig. 1 causes a large artifact due to the presence of magnetic material (solid arrow). Blue eyeshadow caused a smaller artifact (open arrow). Three other eyeshadow preparations demonstrated no effect (arrow heads).

blue colour, while the other three were either green or pink. While we knew that these cosmetics were wax based and contained pigments, we were unaware of their constitutents. Analysis of the different preparations was impossible, so enquiry was made to the manufacturer of the mascara and to a number of other cosmetic manufacturers as to the constituents of mascara and other eye makeup preparations. The main constituents of these preparations are natural and synthetic waxes, glycerine, vinyl acetate, aluminium or zinc stearate, triethanolamine, hydroxyethylcellulose, water and pigments. A number of different pigments may be used. The commonly used ones in black mascara are bone black from charcoal, lamp black, which is pure carbon, and ultramarine blue, which contains ferric oxide. Brown mascara is likely to contain ferric oxide as its colouring agent. Titanium dioxide and oxides of bismuth may also be used. Most of the modern waterproof mascaras are based on black iron oxide and yellow iron oxide. It was also found that it was highly likely that some mascaras would be contaminated with heavy metals which were introduced during the grinding down of the pigments. DISCUSSION The presence of wax, fatty acids and oils in these preparations may be expected to shorten the relaxation

Mascara-caused MRI artifacts 0

FRANCS W. SMITH AND GORDON A. CROSHER

time but not to cause destruction of the adjacent image. The more likely causes are the pigments and impurities which are also present. The mascara preparation used by this patient was a dark black colour containing ferric oxide. It is this ferric oxide which we believe was the cause in this case. It may be difficult to predict which eye cosmetics will contain pigments or impurities that are magnetic,

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though it seems likely that those that are blue, brown or yellow are the most likely to cause image degradation. We see no reason why the presence of these cosmetics should be harmful to the patient during MR imaging, but recommend that they be removed prior to imaging of the head so as to avoid artifact production. This is most important when examination of the orbits is being performed.

REFERENCES 1. Edelstein, W.A.; Hutchison, J.M.S.; Johnson, G.; Redpath, T.W. Spin-warp NMR imaging and applications to human whole-body imaging. Physics in Medicine and Biology 2.5:751-756; 1980.

2. Hutchison, J.M.S.; Edelstein, W.A.; Johnson, G. A whole-body NMR imaging machine. Journal of Physics E: Scientific Instruments 13:947-955; 1980.