Ossification of dural folds is very rare and falx ossification is seen in 0.7% of patients 1. Even though, ossification of an isolated site of the falx cerebri is very rare in medical literature 2.
None of the available literature had mentioned whether the gender or ethnicity plays any role in falx ossification.
Since falx cerebri is derived from embryonic mesenchymal cells, occasional ossification might be seen due to friction, haemorrhage or trauma, which results in some osteogenic changes leading to the formation of membranous bone.
Incidence of ossification of falx has been reported in certain medical disorders such as 2-8:
- endocrine disorders (e.g. hyperparathyroidism)
- vitamin D intoxication
- chronic renal failure
- basal cell nevus syndrome
- Maroteaux type brachyolmia
- pseudoxanthoma elasticum
CT scan can clearly distinguish an isolated ossification of the falx from ossification that has spread to the falx from the frontal bone 6.
On magnetic resonance images, falx ossification exhibits a typical appearance consisting of a central marrow-containing portion with signal intensity similar to fat (bright on T1), surrounded by low signal intensity representing cortical bone 1-8.
There is no difficulty identifying the ossification process on CT images, nevertheless on MRI images some differentials should be considered:
- fatty falx cerebri
- falx cerebri calcification
- haemorrhage (in a trauma context)
- 1. Lee DH, Larson TC, Norman D. Falx ossification-MR visualization. Can Assoc Radiol J. 1989;39 (4): 260-2. Pubmed citation
- 2. Suresh Rangoji RAO , et-al. Unusual isolated ossification of falx cerebri: a case report , Neuroanatomy (2007) 6: 54–55 , eISSN 1303-1775 • pISSN 1303-1783
- 3. Debnath J, Satija L, George RA et-al. Computed tomographic demonstration of unusual ossification of the falx cerebri: a case report. Surg Radiol Anat. 2009;31 (3): 211-3. Surg Radiol Anat (full text) - doi:10.1007/s00276-008-0408-4 - Pubmed citation
- 4. Tubbs RS, Kelly DR, Lott R et-al. Complete ossification of the human falx cerebri. Clin Anat. 2006;19 (2): 147-50. Clin Anat (abstract) - doi:10.1002/ca.20162 - Pubmed citation
- 5. Sands SF, Farmer P, Alvarez O et-al. Fat within the falx: MR demonstration of falcine bony metaplasia with marrow formation. J Comput Assist Tomogr. 1987;11 (4): 602-5. Pubmed citation
- 6. Freyschmidt J, Brossmann J, Sternberg A et-al. Freyschmidt's "Koehler. Thieme. (2003) ISBN:1588901505. Read it at Google Books - Find it at Amazon
- 7. Batnitzky S, Powers J, Schechter M. Falx “calcification” — Does this exist?. Neuroradiology. 1974;7 (5): 255-260. Neuroradiology (abstract) - doi:10.1007/BF00344244
- 8. Tobias JA, Solla KP, Sheldon JJ et-al. MR demonstration of falx ossification: recognition and differential diagnosis. AJNR Am J Neuroradiol. 1987;8 (3): 577-8. AJNR Am J Neuroradiol (citation) - Pubmed citation