Characterization of tumors of jaw:Additive value of contrast enhancement and dual-energy computed tomography

BACKGROUND Currently,the differentiation of jaw tumors is mainly based on the lesion’s morphology rather than the enhancement characteristics,which are important in the differentiation of neoplasms across the body.There is a paucity of literature on the enhancement characteristics of jaw tumors.This is mainly because,even though computed tomography(CT)is used to evaluate these lesions,they are often imaged without intravenous contrast.This study hypothesised that the enhancement characteristics of the solid component of jaw tumors can aid in the differentiation of these lesions in addition to their morphology by dual-energy CT,therefore improving the ability to differentiate between various pathologies.AIM To evaluate the role of contrast enhancement and dual-energy quantitative parameters in CT in the differentiation of jaw tumors.METHODS Fifty-seven patients with jaw tumors underwent contrast-enhanced dual-energy CT.Morphological analysis of the tumor,including the enhancing solid component,was done,followed by quantitative analysis of iodine concentration(IC),water concentration(WC),HU,and normalized IC.The study population was divided into four subgroups based on histopathological analysis-central giant cell granuloma(CGCG),ameloblastoma,odontogenic keratocyst(OKC),and other jaw tumors.A one-way ANOVA test for parametric variables and the Kruskal-Wallis test for nonparametric variables were used.If significant differences were found,a series of independent t-tests or Mann-Whitney U tests were used.RESULTS Ameloblastoma was the most common pathology(n=20),followed by CGCG(n=11)and OKC.CGCG showed a higher mean concentration of all quantitative parameters than ameloblastomas(P<0.05).An IC threshold of 31.35×100μg/cm^(3) had the maximum sensitivity(81.8%)and specificity(65%).Between ameloblastomas and OKC,the former showed a higher mean concentration of all quantitative parameters(P<0.001),however when comparing unilocular ameloblastomas with OKCs,the latter showed significantly higher WC.Also,ameloblastoma had a higher IC and lower WC compared to“other jaw tumors”group.CONCLUSION Enhancement characteristics of solid components combined with dual-energy parameters offer a more precise way to differentiate between jaw tumors.

Contrast-enhanced multidetector computed tomography features and histogram analysis can differentiate ameloblastomas from central giant cell granulomas

BACKGROUND No qualitative or quantitative analysis of contrast-enhanced computed tomography(CT)images has been reported for the differentiation between ameloblastomas and central giant cell granulomas(CGCGs).AIM To describe differentiating multidetector CT(MDCT)features in CGCGs and ameloblastomas and to compare differences in enhancement of these lesions qualitatively and using histogram analysis.METHODS MDCT of CGCGs and ameloblastomas was retrospectively reviewed to evaluate qualitative imaging descriptors.Histogram analysis was used to compare the extent of enhancement of the soft tissue.Fisher’s exact tests and Mann–Whitney U test were used for statistical analysis(P<0.05).RESULTS Twelve CGCGs and 33 ameloblastomas were reviewed.Ameloblastomas had a predilection for the posterior mandible with none of the CGCGs involving the angle.CGCGs were multilocular(58.3%),with a mixed lytic sclerotic appearance(75%).Soft tissue component was present in 91%of CGCGs,which showed hyperenhancement(compared to surrounding muscles)in 50%of cases,while the remaining showed isoenhancement.Matrix mineralization was present in 83.3%of cases.Ameloblastomas presented as a unilocular(66.7%),lytic(60.6%)masses with solid components present in 81.8%of cases.However,the solid component showed isoenhancement in 63%.No matrix mineralization was present in 69.7%of cases.Quantitatively,the enhancement of soft tissue in CGCG was significantly higher than in ameloblastoma on histogram analysis(P<0.05),with a minimum enhancement of>49.05 HU in the tumour providing 100%sensitivity and 85%specificity in identifying a CGCG.CONCLUSION A multilocular,lytic sclerotic lesion with significant hyperenhancement in soft tissue,which spares the angle of the mandible and has matrix mineralization,should indicate prospective diagnosis of CGCG.

Imaging of the pediatric thymus:Clinicoradiologic approach

The thymus is a lymphatic organ that undergoes dynamic changes with age and disease.It is important to be familiar with these physiological changes in the thymus gland to be able to identify pathology and make an accurate diagnosis.The thymus may be involved in multisystem disorders or show focal isolated lesions.The aim of this article is to review the radiological anatomy of the thymus,normal variants,and pathology including hyperplasia and benign/malignant lesions involving the thymus gland in the pediatric age group.We also propose an algorithmic approach for imaging evaluation of a suspected thymic mass on the basis of morphologic features.