AJR 2004; 182:532
© American Roentgen Ray Society
Magnetic Susceptibility Artifacts on MRI: A Hairy Situation
Robert C. McKinstry, III1 and
Delma Y. Jarrett2
1 Mallinckrodt Institute of Radiology St. Louis, MO 63110
2 Memorial Sloan-Kettering Cancer Center New York, NY 10021
A 15-year-old black boy was admitted to the hospital with headache, fever,
proptosis of the left eye, and restricted gaze. He had presented to an
emergency department the previous day with a 5-day history of a headache.
After physical examination had revealed no significant findings and CT of the
head reportedly had shown normal findings, the patient had been discharged
home. MRI and repeated head CT performed at admission (Fig.
1A and
1B) revealed acute sinusitis
complicated by a left periorbital abscess and multiple subdural empyemas. The
patient then underwent bur hole drainage of the subdural empyemas, incision
and drainage of the periorbital abscess, and endoscopic sinus surgery. After
these procedures, the patient made a full recovery.
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Fig. 1A. —15-year-old boy with acute sinusitis and subdural empyemas.
Gadolinium-enhanced sagittal (A) and coronal (B) T1-weighted
images show left subdural empyema and image distortion from susceptibility
artifacts caused by iron oxide particles suspended in beeswax dressing in
patient's hair.
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Fig. 1B. —15-year-old boy with acute sinusitis and subdural empyemas.
Gadolinium-enhanced sagittal (A) and coronal (B) T1-weighted
images show left subdural empyema and image distortion from susceptibility
artifacts caused by iron oxide particles suspended in beeswax dressing in
patient's hair.
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Of particular interest in this case was the unusual artifact seen on
gadolinium-enhanced MRI. The appearance of the artifact suggested that it was
caused by the patient's hair "twists," a style popular in the
black community. Twisting the hair requires the use of products such as gel or
beeswax to hold the hair in place. Hair stylists use either untinted beeswax
or black beeswax tinted with pigments containing iron oxide. Further
investigation revealed that our patient used black beeswax in his hair,
causing the observed paramagnetic effect. Similar artifacts are commonly known
to be caused by cosmetics containing iron and cobalt pigments.
This case is similar to one that Duncan
[1] previously described in
AJR as a culturally linked imaging artifact: an MR artifact was seen
in a traditional healer in South Africa who used a clay paste containing iron
oxide to dress her braids. However, cases such as ours are more likely to be
encountered by radiologists in the United States, especially considering the
growing popularity among American blacks of hair styles— such as twists
and dreadlocks—that require the use of beeswax.
References
- Duncan IC. The "aura" sign: an unusual cultural variant
affecting MR imaging. (letter) AJR2001; 177:1487[Free Full Text]
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