Influence of an object's z-axis location and location on the axial plane on the voxel value representation and uniformity in cone beam computed tomography.

OBJECTIVE: This study aimed to determine the influence of an object's z-axis location and location on the axial plane on the voxel values in cone beam computed tomography. STUDY DESIGN: The CTP401 and CTP486 of the Catphan 500 phantom were scanned with an Alphard-3030 at 6 locations in the z-axis. RESULTS: In CTP401, the voxel values of 3 inserts showed the lowest values when the center of the radiation field corresponded to under 2 or 4 cm of the z-axis center of CTP401. In CTP486, the voxel values showed the lowest values when the center of the radiation field corresponded to under 2 or 4 cm of the z-axis center of CTP486. On the same axial plane, the voxel values at the center showed significantly lower values than the off-center locations (P = .002). CONCLUSIONS: The voxel values in the Alphard-3030 changed based on the z-axis location of the radiation field and were nonuniform on the same axial plane.

Two unique cases of calcifying cystic odontogenic tumor in the maxillary posterior region.

A calcifying cystic odontogenic tumor (CCOT) is an uncommon odontogenic tumor with a predilection for the anterior part of the jaws. We report on 2 cases of CCOT in the posterior maxilla involving the maxillary sinus. In the first case, conventional radiography found a well-defined unilocular lesion. Internal calcification was identified on cone beam computed tomography (CBCT) images. Radiographically, the second case showed 2 large locules with a large complex odontoma and an embedded third molar. By revealing the internal calcification of the lesion, CBCT was helpful in the differential diagnosis of the first case. In both cases, CBCT illustrated the tumor extension and the relationship of the tumor to the maxillary sinus. Therefore, CBCT was an important tool for developing effective treatment plans for lesions in the posterior maxillary region.

Contrast-enhanced multidetector computerized tomography for odontogenic cysts and cystic-appearing tumors of the jaws: is it useful?

OBJECTIVE: The purpose of this study was to investigate the usefulness of computerized tomography (CT), particularly contrast-enhanced CT, in differentiation of jaw cysts and cystic-appearing tumors. STUDY DESIGN: We retrospectively analyzed contrast-enhanced CT images of 90 patients with odontogenic jaw cysts or cystic-appearing tumors. The lesion size and CT values were measured and the short axis to long axis (S/L) ratio, contrast enhancement (CE) ratio, and standard deviation ratio were calculated. RESULTS: The lesion size and the S/L ratio of keratocystic odontogenic tumors were significantly different from those of radicular cysts and follicular cysts. There were no significant differences in the CE ratio among the lesions. CONCLUSIONS: Multidetector CT provided diagnostic information about the size of odontogenic cysts and cystic-appearing tumors of the jaws that was related to the lesion type, but showed no relation between CE ratio and the type of these lesions.

Calcifying cystic odontogenic tumor and adenomatoid odontogenic tumor: radiographic evaluation.

OBJECTIVES: The aim of this study was to describe the radiographic features of calcifying cystic odontogenic tumors (CCOTs) and adenomatoid odontogenic tumors (AOTs) and to compare the radiographic findings for these 2 lesions. STUDY DESIGN: We retrospectively reviewed radiographs of CCOTs and AOTs. Location, border, relationship of the lesion with the impacted tooth, calcification patterns, tooth displacement, and root resorption were evaluated. RESULTS: Nine CCOTs and 8 AOTs were reviewed. Most CCOTs and AOTs had smooth borders. Three CCOTs and 7 AOTs enclosed impacted teeth. Of these cases, the radiolucencies of 3 CCOTs and 1 AOT were attached to the impacted teeth at the cementoenamel junctions. Three AOTs enclosed more portions of the roots, and the other 3 AOTs enclosed the entire teeth. Calcification in CCOTs appeared as a thin radiopaque line (2 cases) and discrete radiopaque foci (1 case), whereas AOTs had numerous dispersed or clustered radiopaque foci (4 cases). CONCLUSIONS: Radiolucency with numerous radiopaque foci (particularly when the radiolucency surrounds a portion of the root or entire tooth) is suggestive of an AOT rather than a CCOT.

Calcifying cystic odontogenic tumor associated with other lesions: case report with cone-beam computed tomography findings.

The calcifying cystic odontogenic tumor (CCOT) simultaneously occurring with other lesions at different locations in the same patient is rare. We report a patient with CCOT associated with an odontoma, a supernumerary tooth, and a dentigerous cyst simultaneously occurring in the maxilla. Cone-beam computed tomography (CBCT) images showed a well-defined expansile lesion with internal calcification, high-density masses surrounded by low-density area, and a supernumerary tooth at the anterior maxilla. Posterolaterally to these lesions, an embedded canine with pericoronal radiolucency was detected. Histopathologic examination revealed a CCOT associated with an odontoma, a supernumerary tooth, and a dentigerous cyst of the embedded canine. Enucleation was performed, and a 2-year postoperative follow-up was uneventful. CBCT was useful in giving the differential diagnosis by depicting internal calcification of CCOT, and in revealing the extent and complex relationship of these lesions.

Investigation of basement membrane proteins in a case of granular cell ameloblastoma.

Granular cell ameloblastoma is a rare, benign neoplasm of the odontogenic epithelium. A case of massive granular cell ameloblastoma in a 44-year-old Thai female is reported. Histopathological features displayed a follicular type of ameloblastoma with an accumulation of granular cells residing within the tumor follicles. After treatment by partial mandibulectomy, the patient showed a good prognosis without recurrence in a 2-year follow-up. To characterize the granular cells in ameloblastoma, we examined the expression of basement membrane (BM) proteins, including collagen type IV, laminins 1 and 5 and fibronectin using immunohistochemistry. Except for the granular cells, the tumor cells demonstrated a similar expression of BM proteins compared to follicular and plexiform ameloblastomas in our previous study, whereas the granular cells showed strong positivity to laminins 1 and 5 and fibronectin. The increased fibronectin expression in granular cells suggests a possibility of age-related transformation of granular cells in ameloblastoma.

Radiographic features of a patient with both cemento-ossifying fibroma and keratocystic odontogenic tumor in the mandible: a case report and review of literature.

We herein describe a rare case of a 48-year-old woman with both ossifying fibroma (OF) and keratocystic odontogenic tumor (KCOT) in the mandible. CT images showed a 15 × 15 × 20-mm radiolucent-radiopaque lesion with bucco-lingual bony expansion in the left first premolar equivalent area of the mandible, and a 15 × 40 × 35-mm well-defined unilocular radiolucent lesion in the left side of the mandible, extending from the distal side of the distal root of the left second molar to the left mandibular ramus. A biopsy of the radiolucent-radiopaque lesion and fenestration surgery of the radiolucent lesion were performed. Histopathologic examination revealed a fibro-osseous lesion (FOL) and a KCOT, respectively. CT was useful in diagnosing the radiolucent-radiopaque lesion as OF and for detecting the 3-dimensional bone expansion and the contents in the lumen of the KCOT.

Correlation between pixel values in a cone-beam computed tomographic scanner and the computed tomographic values in a multidetector row computed tomographic scanner.

OBJECTIVES: The study's objectives were to investigate the correlation between pixel values obtained from a cone-beam computed tomographic (CBCT) scanner and the computed tomographic (CT) values from a multidetector row CT scanner and to determine whether they have a linear relationship at various tube voltages and tube currents. METHODS: A phantom with different concentrations of contrast medium at the center of a multidetector row CT and a CBCT scanner was scanned at various imaging parameters. Computed tomographic values and pixel values were measured using ImageJ. Regression analysis was performed, as well as correlation tests with a Pearson correlation coefficient. RESULTS: A significant correlation between pixel values and the CT values of the same specimen was observed (P < 0.0001), and a linear relationship was found between the values from the 2 scanners at each parameter. CONCLUSIONS: A high correlation and linear relationship between the CT values and pixel values were found at each parameter. Therefore, linear functions can be used to convert a pixel value from the CBCT machine used in this study to the CT values.

Postoperative maxillary cysts: magnetic resonance imaging compared with computerized tomography.

OBJECTIVES: The aim was to investigate magnetic resonance (MR) and computerized tomography (CT) images and compare MR and CT image features of postoperative maxillary cysts (POMC). STUDY DESIGN: We retrospectively evaluated MR and CT images of 7 POMC patients. Number of the cysts, border, bone expansion, CT value, signal intensity, and contrast enhancement were observed. RESULTS: On CT images, 15 cysts were detected. Fourteen cysts showed smooth border. Bone expansion was found in 10 cysts. Mean CT value of each cyst ranged from 23 to 50 Hounsfield units. On MR images, 18 cysts were detected. Twelve cysts showed smooth border. Bone expansion was not observed. Most cysts showed intermediate signal intensity on T1-weighted images, and high or nonhomogeneous intermediate/high signal intensity on T2-weighted images with the fat suppression technique. No cyst showed contrast enhancement in both examinations. CONCLUSION: The CT images revealed bony information, and the MR images clearly demonstrated border of POMC. POMC should be evaluated with both CT and MR imaging.

Computerized tomography observation of a calcifying cystic odontogenic tumor with an odontoma: case report.

The calcifying cystic odontogenic tumor is a rare benign odontogenic lesion. This report documents a case of this lesion associated with odontoma arising from the anterior maxilla in a 14-year-old boy. The diagnosis was confirmed based on computerized tomography findings, which clearly depicted the internal structures obscured in conventional images.