Although a combination of T1 and T2 sequences is needed for a complete MR study, differential diagnosis between odontogenic cystic lesion as keratocyst, follicular cyst and ameloblastoma is made with T1 sequence + i.v. contrast medium (i.e. Gadolinium chelate) with or without fat suppression. Contrast medium in fact allows to recognize solid, vascularized components within ameloblastoma. More recently Diffusion Weighted Imaging (DWI) sequences were also employed to discriminate between ameloblastoma and keratocyst. DWI is a technique that utilises the measurement of Brownian motion of molecules in the attempt of tissue characterization. Different ADC values were obtained between cystic compent of ameloblastoma (higher values) and keratocyst (lower values).

Dear Antonio,

Thank you for this helpful answer. as you said above that ADC values could helps in differentiate between this 2 lesion, ADC for enhancing or nonenhancing lesion. In other words .Apparent diffusion coefficient for centers of lesion or their walls .  

Dear Essam,

Thanks for your reply. Just to clarify: ADC seems useful to discriminate only cystic portions of ameloblastoma vs cheratocyst, not for lesion wall. Usually lesion wall enhances after i.v. contrast medium on T1 sequences in both lesions, but ameloblastoma in most cases is retained to have a thicker peripheral enhancement in unilocular lesions. Suggested papers are Br J Radiol 2012 Oct;85(1018):e864-70 by Srinivasan K et al, Oral Oncol 2011 Feb;47(2):147-52 by Hisatomi M et al.

Dear Antonio,

Thanks for your suggested paper, already I have read it. Do you know very recent papers (above 2013) other than this. Dose the ADC seems to be reliable method to differentiate for all lesions?