Differentiation of radicular cysts and radicular granulomas via texture analysis of multi-slice computed tomography images.

OBJECTIVES: This study aimed to establish a method for differentiating radicular cysts from granulomas via texture analysis (TA) of multi-slice computed tomography (CT) images. METHODS: A total of 222 lesions with multi-slice computed tomography images acquired at our hospital between 2013 and 2022 that were pathologically diagnosed were included in this study. Cases of contrast-enhanced images, severe metallic artefacts, and lesions that were not sufficiently large to be analysed were excluded. The images were chronologically divided into a training group and a validation group. The radiological characteristics were determined. Subsequently, a TA was performed. Pyradiomics software was used for the TA of three-dimensionally segmented volumes extracted from 2 mm slice thickness images with a soft-tissue algorithm. Features that differed significantly between the two lesions in the training group were extracted and used to create machine-learning models. The discriminative ability of these models was evaluated in the validation group using receiver operating characteristic curve analysis. RESULTS: A total of 131 lesions, comprising 28 radicular cysts and 103 granulomas, were analysed. Forty-three texture features that exhibited significant variations were extracted. A support vector machine and decision tree model, with areas under the curves of 0.829 and 0.803, respectively, were created. These models showed high discriminative abilities, even for the validation group, with areas under the curve of 0.727 and 0.701, respectively. Both models showed superior performance compared with that of the models based on radiographic findings. CONCLUSION: Discriminatory models were established for the TA of radicular cysts and granulomas using CT images.

Primordial odontogenic tumor occurred in the maxilla with unique calcifications and its crucial points for differential diagnosis.

Primordial odontogenic tumor (POT) is a newly classified, mixed epithelial and mesenchymal odontogenic tumor, with only 17 reported cases to date. Herein, we report a case of POT that occurred in the right maxilla of a 10-year-old boy and reveal unique features in comparison with those previously reported. Radiologically, the lesion presented as a well-defined, unilocular radiolucency with notable radiopaque foci on the periphery. Microscopically, the tumor was mainly composed of dental papilla-like myxoid fibrous connective tissue, largely surrounded by non-keratinized squamous epithelium with numerous calcified particles, and partly enclosed by inner enamel epithelium-like columnar cells and enamel organ-like structures accompanied with cuboidal and/or stellate reticulum-like cells. Immunohistochemically, the epithelium tested positive for cytokeratin 14 and 19. Moreover, amelogenin and ameloblastin, matrix proteins relating to enamel formation, were positive in the covering epithelium. The tumor was enucleated as a whole, and no recurrence was recorded thereafter. Although the presence of numerous calcified particles was unique, we diagnosed this lesion as POT based on the above-described features. Furthermore, we emphasize the importance of the differential diagnosis of POT and other odontogenic tumors that resemble corresponding tooth germ components.

Application of diffusion kurtosis imaging to odontogenic lesions: Analysis of the cystic component.

PURPOSE: To assess the feasibility of applying diffusion kurtosis imaging (DKI) to common odontogenic lesions and to compare its diagnostic ability versus that of the apparent diffusion coefficient (ADC) for differentiating keratocystic odontogenic tumors (KCOTs) from odontogenic cysts. MATERIALS AND METHODS: Altogether, 35 odontogenic lesions were studied: 24 odontogenic cysts, six KCOTs, and five ameloblastomas. The diffusion coefficient (D) and excessive kurtosis (K) were obtained from diffusion-weighted images at b-values of 0, 500, 1000, and 1500 s/mm2 on 3T magnetic resonance imaging (MRI). The combination of D and K values showing the maximum density of the probable density function was estimated. The ADC was obtained (0 and 1000 s/mm2 ). Values for odontogenic cysts, KCOTs, and ameloblastomas were compared. Multivariate logistic regression modeling was performed to assess the combination of D and K model versus ADC for differentiating KCOTs from odontogenic cysts. RESULTS: The mean D and ADC were significantly higher for ameloblastomas than for odontogenic cysts or KCOTs (P < 0.05). The mean K was significantly lower for ameloblastomas than for odontogenic cysts or KCOTs (P < 0.05). The mean values of all parameters for odontogenic cysts and KCOTs showed no significant differences (P = 0.369 for ADC, 0.133 for D, and 0.874 for K). The accuracy of the combination of D and K model (76.7%) was superior to that of ADC (66.7%). CONCLUSION: Use of DKI may be feasible for common odontogenic lesions. A combination of DKI parameters can be expected to increase the accuracy of its diagnostic ability compared with ADC. J. Magn. Reson. Imaging 2016;44:1565-1571.

Mandibular lingual canals distribute to the dental crypts in prenatal stage.

PURPOSE: To describe configurations of human prenatal mandibular, lingual canals using a limited-field cone beam computed tomography (CBCT) to examine their origin and anatomical significance. MATERIALS AND METHODS: Nine fetal mandibles were examined using a CBCT. Mandibular maturity was assessed according to the mandibular size measured directly and image findings on development of dental crypts. Mandibular, lingual canals and the related foramina (mandibular, mental, and lingual foramina) were observed on axial, sagittal, and cross-sectional images. The horizontal position of mental and lingual foramina was assessed by direct observation using a loupe. RESULTS: In all nine mandibles, CBCT images depicted three separate mandibular canals, which individually occurred at the ramus area. One was a short canal directly connecting to the permanent molar crypt. The other two showed a parallel course, following the mandibular corpus toward the frontal area; the upper one connected to the mental foramen, and the lower one distributed anterior area of canine and incisor crypts. Lingual foramina were observed bilaterally in eight of nine mandibles, whose horizontal position was lingual against the crypt of deciduous canine. The lingual canals occurred from lingual foramina, and connected to the close deciduous tooth crypt or the mandibular canal distributing in the frontal area. CONCLUSIONS: It was suggested human dentition could be developed by plural mandibular and lingual canals.

Potential of preoperative fluorodeoxyglucose-positron emission tomography/computed tomography to diagnose contralateral lymph node metastases in patients with oral cancer.

OBJECTIVE: To establish a decision tree using preoperative PET/computed tomography (CT) parameters for detecting contralateral lymph node metastasis (CLNM) in oral cancer patients. METHODS: In total, 140 patients with a confirmed histopathological diagnosis of oral carcinoma showed fluorodeoxyglucose accumulation of contralateral lymph nodes in PET images. Of 260 lymph nodes, eight were metastatic. We compared metastatic and non-metastatic nodes using Fisher-Freeman-Halton exact and Fisher's exact and Mann-Whitney U tests. The diagnostic performance was analyzed using receiver operating characteristic curves. We established a decision tree using exhaustive chi-squared automatic interaction detection algorithm. RESULTS: Five PET/CT parameters were significantly different between metastatic and non-metastatic nodes: the longest ( P  = 0.015) and shortest ( P  = 0.023) diameter, and the maximum standardized uptake values (SUVmax) of the contralateral node ( P  = 0.030), primary tumor ( P  < 0.001), and ipsilateral node ( P  < 0.001). The area under the curves of SUVmax of the primary tumor (0.887), ipsilateral node (0.886), and longest diameter (0.752) were the largest and these three parameters were used as predictive criteria in the decision tree. The accuracy of the decision tree was 97.7% with 100% sensitivity and 97.6% specificity. CONCLUSION: Preoperative PET/CT imaging with a decision tree has the potential to diagnose CLNM in patients with oral cancer.

Magnetic resonance imaging of methotrexate-related lymphoproliferative disorder with a chief complaint of oral symptoms.

OBJECTIVES: To determine the magnetic resonance imaging (MRI) features of methotrexate-related lymphoproliferative disorder (MTX-LPD) in the oral cavity of a patient with a chief complaint of oral symptoms. METHODS: We included six patients who visited our hospital between November 2014 and November 2019, histopathologically diagnosed with MTX-LPD. All images were examined using 3 T MRI and reviewed by two radiologists. RESULTS: Masses were detected in five cases; all masses demonstrated signal hypointensity and homogeneous signal hyperintensity on T1- and T2-weighted images with fat suppression. Homogeneous enhancement with fat suppression was evident on post-contrast T1-weighted imaging. We performed dynamic contrast-enhanced MRI in three cases and observed early enhancement with a low washout ratio pattern in all cases. Four patients underwent diffusion-weighted MRI and revealed low mean apparent diffusion coefficient (ADC) of 0.57 (range 0.5-0.65) × 10-3 mm2/s. CONCLUSIONS: We reported on the imaging characteristics of six rare cases of MTX-LPD in the oral cavity. Homogeneous hyperintensity on fat-suppressed T2-weighted images and low ADC values are possible features of MTX-LPD. Moreover, MTX-LPD can be differentiated from other carcinomas in the oral cavity.

Effective combination of 3 imaging modalities in differentiating between malignant and benign palatal lesions.

OBJECTIVE: The aim of this study was to evaluate whether computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography/computed tomography (PET/CT) can effectively differentiate between malignant and benign palatal lesions. STUDY DESIGN: In total, 59 patients with palatal lesions (32 malignant and 27 benign), who underwent CT, MRI, and/or PET/CT imaging examinations and had histopathological diagnoses, were divided into an analysis group (n = 46) and a validation group (n = 13). Bone changes adjacent to the lesion, MRI signal intensity, apparent diffusion coefficient (ADC), time to peak enhancement (Tpeak), and maximum standardized uptake values (SUVmax) were evaluated in the analysis group. Diagnostic performance was individually assessed for each parameter for differentiating between malignant and benign lesions. A diagnostic decision tree was constructed by using useful parameters and its accuracy tested in the validation group. RESULTS: The frequency distribution of bone change types and Tpeak differed significantly between malignant and benign lesions. The ADC of malignant lymphoma was significantly lower than that of other lesions. The other parameters did not distinguish between lesion types. The accuracy of the decision tree, constructed by using bone change types, ADC, and Tpeak, was 87.5%. CONCLUSIONS: Bone change types, ADC values, and Tpeak are useful for differentiating between malignant and benign palatal lesions.

Anatomical characteristics of the mandibular lingual foramina observed on limited cone-beam CT images.

OBJECTIVES: The study aimed to investigate the regional frequency and anatomical properties of mandibular lingual foramina. MATERIAL AND METHODS: The regional frequency of the lingual foramina was investigated using limited cone-beam computed tomographic images of mandibles obtained from 190 examinations of 181 patients. The mesio-distal position of the lingual foramina was classified into 17 areas of the midline area and each tooth area. The vertical position was assessed from the positional relationship between the lingual foramina and mandibular canals. Additionally, anastomoses of the lingual canals from the lingual foramina to mandibular canals were observed on the images. RESULTS: One hundred and fifty-four lingual foramina were observed. The highest regional frequency was recognized in the midline area followed by second premolar and canine area. Plural lingual foramina were observed only in the midline areas. No lingual foramina were observed in the superior area of the mandibular canals. Thirty-one lingual foramina showed anastomoses between the lingual canals and mandibular canals. CONCLUSION: Information on the high regional frequency of lingual foramina in the second premolar area would be clinically significant to avoid life-threatening incidents because of the possible presence of an artery. It is therefore important to confirm the location of lingual foramina.

Quantitative evaluation of artefact reduction from metallic dental materials in short tau inversion recovery imaging: efficacy of syngo WARP at 3.0 tesla.

OBJECTIVES: To evaluate the effects of syngo WARP on reducing metal artefacts from dental materials. METHODS: Short tau inversion recovery (STIR) with syngo WARP [a dedicated metal artefact reduction sequence in combination with view-angle-tilting (VAT)] was performed using phantoms of three dental alloys: cobalt-chromium (Co-Cr), nickel-chromium (Ni-Cr), and titanium (Ti). Artefact volumes and reduction ratios of black, white and overall artefacts in the standard STIR and syngo WARP images with several different parameter settings were quantified according to standards of the American Society for Testing and Materials F2119-07. In all sequences, the artefact volumes and reduction ratios were compared. The modulation transfer function (MTF) and contrast-to-noise ratio (CNR) were also measured for evaluation of image quality. RESULTS: In standard STIR, the overall artefact volume of Co-Cr was markedly larger than those of Ni-Cr and Ti. All types of artefacts tended to be reduced with increasing receiver bandwidth (rBW) and VAT. The effect of artefact reduction tended to be more obvious in the axial plane than in the sagittal plane. Compared with standard STIR, syngo WARP with a matrix of 384 × 384, receiver bandwidth of 620 Hz/pixel, and VAT of 100 % in the axial plane obtained reduction effects of 30 % (white artefacts), 45 % (black artefacts), and 38 % (overall artefacts) although MTF and CNR decreased by 30 and 22 % compared with those of standard STIR, respectively. CONCLUSIONS: syngo WARP for STIR can effectively reduce metal artefacts from dental materials.

Diagnostic abilities of 3T MRI for assessing mandibular invasion of squamous cell carcinoma in the oral cavity: comparison with 64-row multidetector CT.

OBJECTIVES: To evaluate the diagnostic accuracies of 3T MRI in evaluating mandibular invasion of squamous cell carcinoma (SCC) in the oral cavity and to compare those with that of multidetector CT (MDCT). METHODS: 41 cases with oral SCC examined by both 3T MRI and MDCT prior to surgery were included in this study. Intravenous contrast medium was administered in all examinations. Images were evaluated for the presence or absence of mandibular invasion and mandibular canal involvement by the tumour. For MRI, both two-dimensional (2D) fast spin echo (FSE) and three-dimensional (3D) volumetric interpolated breath-hold examination (VIBE) images were used for the evaluation. For MDCT, dental CT cross-sectional images were rused. The results were correlated with histopathological findings, and sensitivity and specificity of each imaging technique were calculated.DMFR prrof. RESULTS: Histopathologically, 32 of 41 cases had mandibular invasion and 10 cases had mandibular canal involvement. For mandibular invasion, all three imaging techniques showed sensitivities of 100%. However, the specificities of 2D FSE (56%) and 3D VIBE (78%) were lower than that of MDCT (89%), although the differences were not significant. For mandibular canal involvement, whereas the sensitivities of all three imaging techniques were 100%, the specificities of 2D FSE, 3D VIBE and MDCT were 54, 62 and 85%, respectively. The specificity of 2D FSE was significantlylower than that of MDCT (P < 0.017). CONCLUSIONS: In the evaluation of mandibular invasion, 3T MRI was not as accurate as MDCT. In particular, 2D FSE sequences showed significantly lower specificity than MDCT in evaluating the extent of mandibular invasion. The use of 3D VIBE sequence slightly improved the low specificity of 2D FSE sequences.

Spatial resolution measurements by Radia diagnostic software with SEDENTEXCT image quality phantom in cone beam CT for dental use.

OBJECTIVES: We aimed to employ the Radia diagnostic software with the safety and efficacy of a new emerging dental X-ray modality (SEDENTEXCT) image quality (IQ) phantom in CT, and to evaluate its validity. METHODS: The SEDENTEXCT IQ phantom and Radia diagnostic software were employed. The phantom was scanned using one medical full-body CT and two dentomaxillofacial cone beam CTs. The obtained images were imported to the Radia software, and the spatial resolution outputs were evaluated. The oversampling method was employed using our original wire phantom as a reference. The resultant modulation transfer function (MTF) curves were compared. The null hypothesis was that MTF curves generated using both methods would be in agreement. One-way analysis of variance tests were applied to the f50 and f10 values from the MTF curves. The f10 values were subjectively confirmed by observing the line pair modules. RESULTS: The Radia software reported the MTF curves on the xy-plane of the CT scans, but could not return f50 and f10 values on the z-axis. The null hypothesis concerning the reported MTF curves on the xy-plane was rejected. There were significant differences between the results of the Radia software and our reference method, except for f10 values in CS9300. These findings were consistent with our line pair observations. CONCLUSIONS: We evaluated the validity of the Radia software with the SEDENTEXCT IQ phantom. The data provided were semi-automatic, albeit with problems and statistically different from our reference. We hope the manufacturer will overcome these limitations.

Resolution characteristics of optical coherence tomography for dental use.

OBJECTIVES: The purpose of this study was to clarify the resolution characteristics of optical coherence tomography (OCT) for dental use. METHODS: Two types of swept-source optical coherence tomography machines were employed in this study. To clarify their resolution characteristics, we newly developed a glass chart device with a ladder pattern of wavelengths, which ranged from 4 × 2 µm to 1024 × 2 µm, as well as a star-target pattern, a grid pattern and a spatial frequency response pattern. The resolving powers and characteristics of the OCTs were subjectively evaluated. RESULTS: The Santec OCT-2000™ (Santec Co., Komaki, Japan) had a resolving power of 64 µm in both the horizontal X and vertical Y directions, while the OCT from Yoshida had a resolving power of 64 µm in the horizontal X direction and 128 µm in the vertical Y direction. The resolving power of the depth Z direction could not be obtained from this study. With the Yoshida OCT, the star-target pattern seemed to be non-symmetrical, owing to an edge enhancement effect, which was revealed when the ladder patterns were placed in a horizontal direction. CONCLUSIONS: This study successfully clarified the resolution characteristics of two types of OCTs. The obtained data may be useful for diagnostic purposes, and the glass chart device used in this study may be useful for OCT quality assurance programmes.

Imaging findings of childhood B-cell lymphoblastic lymphoma in the mental region: a case report.

Lymphoblastic lymphoma (LBL) is an uncommon neoplasm that accounts for about 5% of all non-Hodgkin's lymphomas. Approximately 90% of LBLs are of immature T-cell lineage, with B-cell lymphoblastic lymphoma (B-LBL) accounting for only about 10%. Owing to infrequency, the clinicopathological features and the imaging findings of B-LBL are not well defined. LBLs frequently affect extranodal sites. The most common site is the skin, followed by the bone, and the head and neck region is rarely involved. We report herein a case of childhood B-LBL occurring in the mental region, with emphasis on the findings of several imaging studies, including contrast-enhanced CT, MRI and fluorodeoxyglucose-positron emission tomography/CT.

Evidence that basal activity, but not transactivation, of the epidermal growth factor receptor tyrosine kinase is required for insulin-like growth factor I-induced activation of extracellular signal-regulated kinase in oral carcinoma cells.

IGF-I receptor (IGF-IR) is involved in numerous biological functions via its major downstream signaling molecules, extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3'-kinase/Akt. The IGF-I-induced activation of ERK, but not that of Akt, is reportedly mediated by the transactivation of the epidermal growth factor receptor (EGFR) tyrosine kinase (TK). The mechanism for the EGFR-TK-dependent activation, however, still remains largely unknown. We found that an oral carcinoma cell line overexpressing EGFR, Ca9-22, exhibited IGF-I-induced activation of both Akt and ERK, but that only the latter was significantly decreased by a specific inhibitor of EGFR-TK, tyrphostin AG1478. In this report we provide evidence for the existence in this cell line of a novel mechanism by which IGF-I induces ERK activation in a manner that is dependent on the basal level of EGFR-TK activity, but is independent of receptor transactivation. In addition, we show that c-Raf kinase is likely to be a key regulator of this mechanism. The elucidation of such a unique mechanism involving cross-talk between EGFR and heterologous receptors may shed additional light on the clinical use of EGFR-TK inhibitors in antitumor therapies.

Imaging findings of benign peripheral nerve sheath tumor in jaw.

OBJECTIVE: The aim of this study was to investigate the imaging characteristics of peripheral nerve sheath tumors (PNSTs) in the jaw. STUDY DESIGN: Imaging studies of 6 patients were retrospectively reviewed. Conventional radiography, computed tomography, and magnetic resonance imaging were performed in all patients. RESULTS: A fusiform lesion continuous with the nerve was observed in 2 cases, with the tumor arising within the inferior alveolar canal. In the other 4 cases, with the tumor arising outside the canal, the tumor had protruded and eroded into the bone. Protrusion was also present in 1 of the 2 cases, with the tumor arising within the canal. A target or fascicular sign was observed each in 1 case. CONCLUSIONS: A fusiform lesion continuous with the nerve and a target or fascicular sign was only present in a few cases. The PNSTs, however, showed a tendency to protrude into the bone.

Non-Hodgkin lymphoma involving the mandible: imaging findings.

OBJECTIVE: The aim of this study was to investigate the imaging findings of non-Hodgkin lymphoma (NHL) involving the mandible. STUDY DESIGN: The imaging studies of 4 patients with NHL involving the mandible were retrospectively reviewed. Panoramic and computerized tomographic (CT) images were available for all patients. Magnetic resonance imaging (MRI) was available for 3 patients. RESULTS: On panoramic images, an apparent radiolucent lesion was found in only 2 of 4 cases. However, in all cases careful observation demonstrated imaging findings suggesting malignancy. On CT and MRI, tumor replaced the bone marrow in all cases and spread to the surrounding soft tissue in 3 cases. Cortical bone destruction tended to be mild for the extent of tumor involvement. CONCLUSIONS: NHL involving the mandible tended to show slight or mild cortical bone destruction relative to the extent of the tumor involvement. Careful observation was considered to be necessary when interpreting conventional images, because they might not clearly demonstrate bone destruction.

MRI findings of temporomandibular joints with disk perforation.

OBJECTIVE: To investigate magnetic resonance imaging (MRI) findings of temporomandibular joints (TMJs) with disk perforation. STUDY DESIGN: Thirty-one TMJs (31 patients) with disk perforation, 37 TMJs (34 patients) with anterior disk displacement and no disk perforation, and 22 asymptomatic TMJs of 11 volunteers were examined by MRI. The presence or absence of disk perforation was confirmed by TMJ arthrography. The MR images were evaluated for the presence or absence of disk deformity, disk displacement, condylar bone changes and joint effusion and for visualization of the temporal posterior attachment (TPA) of the posterior disk attachment. Those findings were compared among the 3 groups. RESULTS: The incidences of anterior disk displacement and condylar bone changes in the patients group with disk perforation were significantly higher than in asymptomatic volunteers. Disk deformity and obscurity of TPA were significantly more frequent in the patient group with disk perforation than in the other 2 groups. CONCLUSION: In addition to disk deformity, TPA obscurity was considered to be one of the characteristic MRI findings of TMJs with disk perforation.