Diagnostic value of MRI for odontogenic tumours

Abstract

Objectives: To evaluate the diagnostic value of MRI for odontogenic tumours. Materials and methods: 51 patients with odontogenic tumours were subjected to preoperative MRI examinations. For tumours with liquid components, i.e. ameloblastomas and keratocystic odontogenic tumours (KCOTs), the signal intensity (SI) uniformity of their cystic components (US) was calculated and then their US values were compared. For tumours with solid components that had been examined using dynamic contrast-enhanced MRI (DCE-MRI), their CI max (maximum contrast index), T max (the time when CI max occurred), CI peak (CI max 3 0.90), T peak (the time when CI peak occurred) and CI 300 (i.e. the CI observed at 300 s after contrast medium injection) values were determined from CI curves. We then classified the odontogenic tumours according to their DCE-MRI parameters. Results: Significant differences between the US values of the ameloblastomas and KCOT were observed on T 1 weighted images, T 2 weighted images and short TI inversion recovery images. Depending on their DCE-MRI parameters, we classified the odontogenic tumours into the following five types: Type A, CI peak . 2.0 and T peak , 200 s; Type B, CI peak , 2.0 and T peak , 200 s; Type C, CI 300 . 2.0 and T max , 600 s; Type D, CI 300 . 2.0 and T max . 600 s; Type E, CI 300 , 2.0 and T max . 600 s. Conclusion: Cystic component SI uniformity was found to be useful for differentiating between ameloblastomas and KCOT. However, the DCE-MRI parameters of odontogenic tumours, except for odontogenic fibromas and odontogenic myxomas, contributed little to their differential diagnosis.

Assessment of Apical Periodontitis by MRI: A Feasibility Study

“…However even though destruction of the tumor structure during resection has so far precluded direct comparison between MRI appearance and histological tissue characterization, the presented data revealed strong evidence for the applicability of MRI for the delineation of different lesion types. Fujita et al recently described the diagnostic value of MRI for the differentiation of certain odontogenic tumors [21]. Although the results were promising, one limitation of MRI has been shown to be its relatively low diagnostic ability for the assessment of the course of filled root canals.…”

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.…”

“…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.…”

“…[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. 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.…”

“…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.…”