Subjective Incidental Findings of the Lumbar Spine at MRI

Abstract

In the May 2011 issue of the American Journal of Roentgenology, we read with great interest the article by Park et al. [1] and congratulate the authors for their work. However, we have concerns about some issues in the article.First, the authors diagnosed vertebral hemangioma when signal intensity was increased on T1-weighted images, signal intensity was markedly increased on T2-weighted images, and the vertebral bodies had a mottled appearance [2]. However, some lesions have low signal on T1-weighted images and tend to be more aggressive, and other atypical hemangiomas, such as epithelioid hemangioma and epithelioid hemangioendothelioma, may show a heterogeneous pattern with mixed signal intensity on T1- and T2-weighted MR images that reflects the absence of fat and the presence of inflammatory infiltrate [3]. In Figure 1 of the article by Park et al. [1], vertebral hemangioma must be differentiated from benign fat deposition.Another important bias in the article was subjective inclusion criteria of the incidental findings of the lumbar spine at MRI. The authors included only vertebral hemangioma, Tarlov cyst, fibrolipoma, synovial cyst, and sacral meningocele. However, other asymptomatic incidental findings, such as enostosis [4], meningioma [5], Schmorl node [6], conjoined nerve root [7], and limbus vertebrae [8], were occasionally discovered in the lumbar spine.In summary, because of the aforementioned limitations, the conclusions of the study by Park et al. [1] are not justified and may even be biased. We hope the authors can clarify their rationale for the study design limitations we have noted.