Journal of Mahatma Gandhi Institute of Medical Sciences

LETTER TO EDITOR
Year
: 2021  |  Volume : 26  |  Issue : 2  |  Page : 138--139

“Pseudo-polka dot” and “pseudo-corduroy” signs in osteoporotic spine


Sudhir Saxena, Sonal Saran, Swarnava Tarafdar, Tripti Prajapati 
 Department of Radio-Diagnosis, All India Institute of Medical Sciences, Rishikesh, Uttarakhand, India

Correspondence Address:
Dr. Swarnava Tarafdar
Department of Radio-Diagnosis, All India Institute of Medical Sciences, Rishikesh - 249 203, Uttarakhand
India




How to cite this article:
Saxena S, Saran S, Tarafdar S, Prajapati T. “Pseudo-polka dot” and “pseudo-corduroy” signs in osteoporotic spine.J Mahatma Gandhi Inst Med Sci 2021;26:138-139


How to cite this URL:
Saxena S, Saran S, Tarafdar S, Prajapati T. “Pseudo-polka dot” and “pseudo-corduroy” signs in osteoporotic spine. J Mahatma Gandhi Inst Med Sci [serial online] 2021 [cited 2022 Jul 5 ];26:138-139
Available from: https://www.jmgims.co.in/text.asp?2021/26/2/138/337439


Full Text



Dear Editor,

We would like to highlight two important signs observed in computed tomography (CT) of the spine and designate them the “pseudo-polka dot” and “pseudo-Corduroy” signs. These signs are observed in the axial and sagittal sections of the CT spine, respectively, in vertebral bodies, and are due to prominent vertical trabecular pattern in diffuse osteoporosis. They may be important signs as they may be mistaken for vertebral hemangioma as closely resembles “polka dot” and “corduroy” signs in the axial and sagittal sections, respectively.

The “polka dot sign” is classical of hemangioma of the medullary cavity of the vertebral body where multiple high attenuation dots in a bone window or even in soft tissue window can simulate polka dot of clothing.[1] This is due to thickened trabeculae which occur due to reinforcement of the osseous network adjacent to vascular channels in the hemangioma that have caused bone resorption.[2] The same is the cause of the corduroy sign which is visualized in the sagittal section.[3] This process usually occurs within fatty marrow.[1] The vertebral hemangioma being the most common benign spinal lesion may involve the entire portion of the vertebral body at times or can be in multiple vertebral bodies.[3]

On the other hand, osteoporosis is the most common metabolic bone disorder.[4] The CT features of osteoporosis are diffusely increased radiolucency with a well-demarcated cortical rim and verticalization of the trabecular pattern.[4] There is the prominence of vertical trabeculae with thinning of horizontal or secondary trabeculae of vertebral bodies. In axial and sagittal sections, budding radiologists may mistake it as “polka dot” and “corduroy” signs, respectively, due to their similar appearance. The features favoring osteoporosis are that it should be diffusely present in all vertebral bodies, while hemangioma will be focal and limited to one or a few vertebral bodies [Figure 1].{Figure 1}

The purpose of this article is not to discuss the “polka dot” or “corduroy” signs already discussed in several previous studies but to discuss two signs (“pseudo-polka dot” and “pseudo-Corduroy” signs) not discussed previously in any related articles. This will avoid misdiagnosing the most common benign vertebral body tumor from the most common metabolic bone disorder of the spine.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Persaud T. The polka-dot sign. Radiology 2008;246:980-1.
2Murphey MD, Fairbairn KJ, Parman LM, Baxter KG, Parsa MB, Smith WS. From the archives of the AFIP. Musculoskeletal angiomatous lesions: Radiologic-pathologic correlation. Radiographics 1995;15:893-917.
3Gaudino S, Martucci M, Colantonio R, Lozupone E, Visconti E, Leone A, et al. A systematic approach to vertebral hemangioma. Skeletal Radiol 2015;44:25-36.
4Guglielmi G, Muscarella S, Bazzocchi A. Integrated imaging approach to osteoporosis: State-of-the-art review and update. Radiographics 2011;31:1343-64.