HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Duncan, I. C. Search for Related Content PubMed PubMed Citation Articles by Duncan, I. C. Social Bookmarking                      What's this? Hotlight (NEW!) What's Hotlight?

The "Aura" Sign

An Unusual Cultural Variant Affecting MR Imaging

Sunninghill Medical Institute Sandton, 0140 South Africa

A 51-year-old African woman was admitted to the hospital after experiencing a series of grand mal seizures and the onset of progressively severe intermittent left-sided headaches. Clinical findings were a decreased visual acuity in the patient's left eye and a left-sided third nerve palsy. An initial contrast-enhanced CT scan (Fig. 3A) showed a large left-sided enhancing tumor adjacent to the left sphenoid ridge. MR images (Figs. 3B and 3C) were obtained to provide more anatomic information, and digital subtraction angiography was performed to assess the vascular supply and associated vascular anatomy. The patient then underwent surgery for excision of the tumor, which the postoperative histology confirmed as being a meningioma. What I am addressing in this article is not the tumor itself but rather the effect of scalp and hair dressings on MR imaging.

View larger version (114K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3A. —51-year-old African woman with braided hair dressed with paste derived from clay with high iron oxide content. Imaging was performed before patient underwent surgery to exise meningioma. Axial (A) and coronal (B) contrast-enhanced T1-weighted images show left-sided sphenoid ridge meningioma as well as bright "aura" around skull.

View larger version (142K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3B. —51-year-old African woman with braided hair dressed with paste derived from clay with high iron oxide content. Imaging was performed before patient underwent surgery to exise meningioma. Axial (A) and coronal (B) contrast-enhanced T1-weighted images show left-sided sphenoid ridge meningioma as well as bright "aura" around skull.

View larger version (135K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3C. —51-year-old African woman with braided hair dressed with paste derived from clay with high iron oxide content. Imaging was performed before patient underwent surgery to exise meningioma. Axial contrast-enhanced CT scan reveals tumor and shows aura effect caused by clay-derived dressing on patient's hair braids.

Among several South African tribes—especially the Venda tribe in the Northern Transvaal—women, particularly female traditional healers, braid their hair and then impregnate the braids with a reddish brown paste made from a specific type of clay prevalent in the areas in which the tribes live. The reddish ochre color of the clay results from its high iron oxide content; the iron oxide causes X-ray beam attenuation that is visible on both CT scans and conventional radiographs of the skull (Fig. 3D). In addition, it causes paramagnetic effects around the skull seen most strikingly on T1-weighted MR images, a bright "aura" visible around the patient's head.

View larger version (136K): [in this window] [in a new window] [as a PowerPoint slide]   Fig. 3D. —51-year-old African woman with braided hair dressed with paste derived from clay with high iron oxide content. Imaging was performed before patient underwent surgery to exise meningioma. Lateral radiograph of patient's skull shows density of hair braids.

Most radiologists are aware that the iron-and cobalt-containing pigments in eye makeup result in artifacts on MR images [1], but to my knowledge, this is the first time that a culturally linked artifact of this nature has been described.

References

1. Wesbey G, Adams MK, Edelman RR. Artifacts in MRI: description, causes and solutions. In: Edelman RR, Zlatkin MB, Hesselink JR, eds. Clinical magnetic resonance imaging, 2nd ed. Philadelphia: W. B. Saunders, 1996:88 -91

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				A. Manzella, P. B. Filho, E. Albuquerque, F. Farias, and J. Kaercher Imaging of Gossypibomas: Pictorial Review Am. J. Roentgenol., December 1, 2009; 193(6_Supplement): S94 - S101. [Abstract] [Full Text] [PDF]

				A. Manzella, P. B. Filho, E. Albuquerque, F. Farias, and J. Kaercher Imaging of Gossypibomas: Self-Assessment Module Am. J. Roentgenol., December 1, 2009; 193(6_Supplement): S102 - S105. [Abstract] [Full Text] [PDF]

				R. C. McKinstry III and D. Y. Jarrett Magnetic Susceptibility Artifacts on MRI: A Hairy Situation Am. J. Roentgenol., February 1, 2004; 182(2): 532 - 532. [Full Text] [PDF]

This Article Figures Only Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Duncan, I. C. Search for Related Content PubMed PubMed Citation Articles by Duncan, I. C. Social Bookmarking                      What's this? Hotlight (NEW!) What's Hotlight?