Diffusion-weighted imaging in the evaluation of odontogenic cysts and tumours

Abstract

Objective: The differentiation between keratocystic odontogenic tumour (KCOT) and other cystic/predominantly cystic odontogenic tumours is difficult on conventional CT and MR sequences as there is overlap in the imaging characteristics of these lesions. The purpose of this study was to evaluate the role of diffusion-weighted imaging (DWI) and to assess the performance of apparent diffusion coefficients (ADCs) in the differential diagnosis of odontogenic cysts and tumours. Methods: 20 patients with odontogenic cysts and tumours of the maxillomandibular region were examined with DWI. Diffusion-weighted images were obtained with a single-shot echoplanar technique with b-values of 0, 500 and 1000 s mm 22. An ADC map was obtained at each slice position. Results: The cystic areas of ameloblastoma (n510) , which yielded 100% sensitivity and 100% specificity. Conclusion: DWI can be used to differentiate KCOT from cystic (or predominantly cystic) odontogenic tumours.

Imaging characteristics of ameloblastomas and diagnostic value of computed tomography and magnetic resonance imaging in a series of 26 patients

“…4,5,8 The use of diffusion-weighted MRI and dynamic contrast-enhanced MRI as a means of differentiating KCOTs from the cystic contents of ameloblastomas has been studied based on apparent diffusion coefficient (ADC) values and signal intensities. [11][12][13][14][15][16]14 Srinivasan et al 14 …”

Magnetic resonance imaging: a useful tool to distinguish between keratocystic odontogenic tumours and odontogenic cysts

“…However, conventional panoramic radiographs or CT cannot reliably discriminate between odontogenic cysts, keratocystic odontogenic tumours, and ameloblastomas MRI can, however, help. 9 While some studies have reported on possible differentiation between ameloblastomas and keratocystic odontogenic tumours, [5][6][7][8] or between true cysts and simple bone cysts, 11 we know of little if any detailed work that has focused on discrimination between keratocystic odontogenic tumours and odontogenic cysts based on MRI. Relatively few reported cases reflect this, as none of the relevant studies has included more than 10 cases of each of keratocystic odontogenic tumours and odontogenic cysts.…”

“…5,9 Diffusion-weighted MRI with calculation of apparent diffusion coefficients may be used as an adjunct for differentiation between keratocystic odontogenic tumours and ameloblastomas. 6,8 The strengths of our retrospective analysis include complete radiological and histopathological correlation for each individual lesion, the significance of findings despite the small sample size, and the agreement between two independent observers on the presence of the respective distinguishing features of odontogenic cysts and keratocystic odontogenic tumours on MRI.…”

“…1 technique that is becoming increasingly important in oral and maxillofacial surgery is magnetic resonance imaging (MRI), which has already been evaluated for differentiating between ameloblastomas and keratocystic odontogenic tumours. [5][6][7][8] While dynamic, contrast-enhanced MRI has the potential to show the density of microvessels as a marker of proliferative or inflammatory activity in tissue, it has also been shown to contribute little to the differential diagnosis of odontogenic tumours, except for odontogenic fibromas and myxomas. 7 Diffusion-weighted MRI may help to characterise the contents of odontogenic cysts and tumours, as pure cystic liquids would restrict free Brownian motion of water molecules to a lesser degree than matrix structures within a solid or partly solid tumour.…”

“…7 Diffusion-weighted MRI may help to characterise the contents of odontogenic cysts and tumours, as pure cystic liquids would restrict free Brownian motion of water molecules to a lesser degree than matrix structures within a solid or partly solid tumour. 8 Other studies on MRI have included a larger variety of cystic lesions such as radicular cysts, dentigerous cysts, pseudocysts, dermoid cysts, nasopalatine cysts, and nasolabial cysts. [9][10][11] Differentiation between ameloblastomas and keratocystic odontogenic tumours seems to be promising, [5][6][7][8] but there is to our knowledge little evidence so far about whether it is possible to discriminate between keratocystic odontogenic tumours and odontogenic cysts.…”