Here is a case of Cannavan's Disease for the Radiology Grand Rounds submitted by Dr Sumer Sethi of Teleradiology Providers. Concept and Archive of the Radiology Grand Rounds is available at- Radiology Grand Rounds.
Deficiency of N- acetylaspartate cyclase enzyme – Increase in NAA.
"Canavan disease demonstrates bilateral symmetric T2 white matter hyperintensity, including involvement of the subcortical arcuate fibers. This disease appears diffusely throughout the cerebral white matter, does not enhance at computed tomography (CT) or MR imaging, and demonstrates variable involvement of the basal ganglia and cerebellar white matter. For example, both Canavan disease and Alexander disease demonstrate macrocephaly with bilaterally symmetric increased T2 signal intensity of cerebral white matter and involvement of subcortical arcuate fibers. MR spectroscopy, however, has been shown to be a useful diagnostic tool in making this distinction. There is an accumulation of NAA in patients with Canavan disease because of a deficiency in the myelin synthesis pathway; thus, MR spectroscopy reveals a markedly elevated NAA peak. "
In other white matter diseases there is Axonolysis hence NAA decreases, Defective myelination leads to increased Choline and lactate is seen in the activer disease.
Further reading (Radiology 2006;241:310-324.)
Hope you enjoyed this edition of Radiology Grand Rounds submissions are requested for the next Radiology Grand Rounds posted every month last sunday. If you interested in hosting any of the future issues contact me at sumerdoc-AT-yahoo-DOT-com.
Case by-Dr.Sumer K Sethi, MD
Consultant Radiologist ,VIMHANS and CEO-Teleradiology Providers
Editor-in-chief, The Internet Journal of Radiology
Director, DAMS (Delhi Academy of Medical Sciences)