Assessment of Hounsfield unit in the differential diagnosis of odontogenic cysts.
OBJECTIVES
The purpose of this study was to evaluate the usefulness of Hounsfield unit (HU) assessment with multislice-CT in the differentiation of radicular cysts (RCs), dentigerous cysts (DCs) and odontogenic keratocysts (OKCs).


METHODS
In total, 307 odontogenic cysts (RCs, DCs and OKCs) were included in this study. Cysts with lesion diameter <10 mm, cysts with artefacts affecting measurement of HU values, cysts involving infection and recurrent cysts were regarded as exclusion criteria. Images were acquired in three different types of CT scanners: Aquilion ONE, Discovery CT750 HD and SOMATOM Definition Flash. Differences in HU values among scanners and among types of odontogenic cysts were assessed using one-way analysis of variance; multiple comparisons were performed post hoc, using the Tukey-Kramer honestly significant difference test.


RESULTS
In total, 164 cysts were analysed in this study (64 RCs, 57 DCs and 43 OKCs). Regardless of the type of lesion, the Aquilion ONE scanner demonstrated a significant difference in HU value, compared with the Discovery CT750 HD scanner. Regardless of CT scanner model, HU values significantly differed between DCs and OKCs (p < 0.0001), as well as between OKCs and RCs (p < 0.0001).


CONCLUSIONS
HU values were found to vary among CT scanners and should always be associated with other lesion imaging features while interpreting and elaboration diagnostic hypothesis. Notably, the results suggested that OKCs might be able to be differentiated from DCs and RCs by using HU values.
['Uehara|Kyonori|K|', 'Hisatomi|Miki|M|', 'Munhoz|Luciana|L|', 'Kawazu|Toshiyuki|T|', 'Yanagi|Yoshinobu|Y|', 'Okada|Shunsuke|S|', 'Takeshita|Yohei|Y|', 'Saito|Emiko Arita|EA|', 'Asaumi|Junichi|J|']
D003803:Dentigerous Cyst D003937:Diagnosis, Differential D006801:Humans D007150:Immunohistochemistry D009807:Odontogenic Cysts D011842:Radicular Cyst
odontogenic cyst radicular cyst dentigerous cyst odontogenic keratocyst Multidetector computed tomography