Microscopic calcification within the basal ganglia was reported by Virchow and Bamberger in 1855. The description of symmetrical cerebral calcification, particularly of the basal ganglia and often of the dentate nuclei, associated with hypoparathyrodism as related by Eaton, Camp and Love(1939) was a significant development in the field of calcification. Calcification of the basal ganglia has been visualized by skull radiography and computed tomography(CT) scan, and in two-third of cases, it has been associated with metabolic and endocrine abnormalities. Computed tomography is more sensitive to detect the intracranial calcification than plain skull radiography. The purpose of our report was evaluate the significance of basal ganglia calcification as visualized by CT, discusses on pathogensis of calcification, clinical significance and management under the hypocalemia.
Basal Ganglia* ; Hypoparathyroidism* ; Radiography ; Skull

The following conclusions were obtained from the non-reconstructed and reconstructed subtraction images of the standard intraoral radiographs which were taken with paralleing technique with Rinn XCP only and with occlusal bite registration for geometric standardization using bilateral mandibular premolar and molar regions of two dry humad skulls. 1. The SD of the overall subtraction images of the premolars and molars of the non-reconstructed, tnat is, the manual superimposition showed statistically significant difference between the non-registered and registered groups. 2. In non-reconstructed and non-registered cases, the quality of the subtraction images were improved when superimposition was focally done and this was more evident in areas where the radiographic imaged tend to be distorted due to anatomic readons. 3. In non-restructed and registered cases, the subtraction images were consistent regardless of the anatomic site or the focus superimposition. This means that the geometric standardization with only occlusal bite registration could produce serial radiographs which is suitable for subtraction. 4. The SD of the overall subtraction images of the premolars and molars of the reconstructed, that is, the automatic superimposition showed statistically insignificant difference between the non-registered and registered groups. This means that using reconstruction, subtraction radiography is possible without occlusal bite registration. 5. In reconstructed and non-registered cases, compatible quality of the subtraction images were obtained regardless of the anatomic site or area of the corresponding points. 6. In reconstructed and registered cases, best subtraction images whose quality showed sensitivity to the areas of corresponding points were obtained.
Bicuspid ; Jaw Relation Record ; Molar ; Radiography* ; Skull

Lesions of the skull vault are often incidentally encountered during in plain radiography, CT, and MR imaging of the brain and benign lesions are more common than primary malignancies. The usefulness of plain skull films is limited, but when combined with CT or MRI, there is a high probability of accurate diagnosis. The aim of this essay is to describe a wide range of cranial lesions and to illustrate their distinguishing features.
Brain ; Diagnosis ; Magnetic Resonance Imaging ; Radiography ; Skull*

PURPOSE: The purpose of this study was to evaluate a new technique for localizing impacted mesiodens using its horizontal magnification ratio on panoramic radiographs. MATERIALS AND METHODS: Location-magnification equation of a panoramic equipment was obtained from horizontal magnification ratio of a metal ball which was located variable positions from the center of image layer at interval of 2 mm. Panoramic radiographs were obtained from a skull phantom with a metal ball which was a substitute for impacted mesiodens and was embedded 10mm(Group 1), 15mm(Group 2), and 20mm(Group 3) posterior to the central incisor. Each group obtained 7 panoramic radiographs at variable positions and one periapical radiograph. Three methods were used to estimate the actual width of the incisors and the balls which were used to calculate the magnification ratio. The methods included using the actual incisor width and the calculated ball width (Method 1), using the actual incisor width and the ball widths measured on periapical radiograph (Method 2), and using the incisor and the ball widths measured on periapical radiograph (Method 3). The location of the metal ball was calculated by using the location-magnification equation. RESULTS: The smallest difference between the calculated and the actual distance was 0.1+/-0.7 mm in Group 1/Method 3. The largest difference was -4.2+/-1.6 mm in Group 3/Method 2. In all groups, method 3 was the most accurate. CONCLUSION: Quantitative localization of impacted mesiodens is possible by using panoramic radiograph.
Incisor ; Radiography, Dental ; Radiography, Panoramic ; Skull ; Tooth, Supernumerary

Image resampling is of particular interest in digital radiology. When resampling an image to a new set of coordinate, there appears blocking artifacts and image changes. To enhance image quality, interpolation algorithms have been used. Resampling is used to increase the number of points in an image to improve its appearance for display. The process of interpolation is fitting a continuous function to the discrete points in the digital image. The purpose of this study was to determine the effects of the seven interpolation functions when image resampling in digital periapical images. The images were obtained by Digora, CDR and scanning of Ektaspeed plus periapical radiograms on the dry skull and human subject. The subjects were exposed to intraoral X-ray machine at 60kVp and 70 kVp with exposure time varying between 0.01 and 0.50 second. To determine which interpolation method would provide the better image, seven functions were compared ; (1) nearest neighbor (2) linear (3) non-linear (4) facet model (5) cubic convolution (6) cubic spline (7) gray segment expansion. And resampled images were compared in terms of SNR(Signal to Noise Ratio) and MTF(Modulation Transfer Function) coefficient value. The obtained results were as follows ; 1. The highest SNR value(75.96dB) was obtained with cubic convolution method and the lowest SNR value(72.44dB) was obtained with facet model method among seven interpolation methods. 2. There were significant differences of SNR values among CDR, Digora and film scan(p<0.05). 3. There were significant differences of SNR values between 60kVp and 70kVp in seven interpolation methods. There were significant differences of SNR values between facet model method and those of the other methods at 60kVp(p<0.05), but there were not significant differences of snr values among seven interpolation methods at>0.05). 4. There were significant differences of MTF coefficient values between linear interpolation method and the other six interpolation methods(p<0.05). 5. The speed of computation time was the fastest with nearest neighbor method and the slowest with non-linear method. 6. The better image was obtained with cubic convolution, cubic spline and gray segment method in ROC analysis. 7. The better sharpness of edge was obtained with gray segment expansion method among seven interpolation methods.
Artifacts ; Humans ; Noise ; Radiography, Dental, Digital ; ROC Curve ; Skull

OBJECTIVES: To determine the effect of interpolation functions when processing the digital periapical images. MATERIALS AND METHODS: The digital images were obtained by Digora and CDR system on the dry skull and human subject. 3 oral radiologists evaluated the 3 portions of each processed image using 7 interpolation methods and ROC curves were obtained by trapezoidal methods. RESULTS: The heighest Az value(0.96) was obtained with cubic spline method and the lowest Az value(0.03) was obtained with facet model method in Digora system. The heighest Az value(0.79) was obtained with gray segment expansion method and the lowest Az value(0.07) was obtained with facet model method in CDR system. There was significant difference of Az value in original image between Digora and CDR system at alpha=0.05 level. There were significant differences of Az values between Digora and CDR images with cubic spline method, facet model method, linear interpolation method and non-linear interpolation method at alpha= 0.1 level.
Humans ; Radiography, Dental, Digital ; ROC Curve ; Skull ; Tooth*

PURPOSE: This study was performed to suggest reference line-pair values of panoramic images with clinically desirable qualities using an arch-form phantom stand. MATERIALS AND METHODS: The line-pair test phantom was chosen. A real skull model was selected for setting the arch-form model of the phantom stand. The phantom stand had slits in four regions (incisor, premolar, molar, TMJ). Four raw images of the test phantom in each region and one raw image of the real skull were converted into 50 test phantom images and 50 skull phantom images with various line-pair values. 50 post-processed real skull phantom images were divided into 4 groups and were randomly submitted to 14 evaluators. Image quality was graded on a 4 point scale (1. good, 2. normal, 3. poor but interpretable, and 4. not interpretable). The reference line pair was determined as the first line-pair value scored less than 2 points. RESULT: The mean scores tended to decrease as the line-pair values increased. The reference line-pair values were 3.19 LP/mm in the incisor, 2.32 LP/mm in the premolar and TMJ, and 1.88 LP/mm in the molar region. CONCLUSION: Image quality evaluation methods and criteria should be able to assess various regions considering the characteristics of panoramic systems. This study suggested overall and regional reference line-pair values and established a set of standard values for them.
Bicuspid ; Incisor ; Molar ; Phantoms, Imaging ; Radiography, Panoramic ; Skull ; Temporomandibular Joint

PURPOSE: To compare the leakage and scattered radiation from hand-held dental X-ray unit with radiation from fixed dental X-ray unit. MATERIALS AND METHODS: For evaluation we used one hand-held dental X-ray unit and Oramatic 558 (Trophy Radiologie, France), a fixed dental X-ray unit. Doses were measured with Unfors Multi-O-Meter 512L at the right and left hand levels of X-ray tube head part for the scattered and leakage radiation when human skull DXTTR III was exposed to both dental X-ray units. And for the leakage radiation only, doses were measured at the immediately right, left, superior and posterior side of the tube head part when air was exposed. Exposure parameters of handheld dental X-ray unit were 70kVp, 3mA , 0.1 second, and of fixed X-ray unit 70kVp, 8mA, 0.45 second. RESULTS: The mean dose at the hand level when human skull DXTTR III was exposed with portable X-ray unit 6.39 micronGy, and the mean dose with fixed X-ray unit 3.03 micronGy (p<0.001). The mean dose at the immediate side of the tube head part when air was exposed with portable X-ray unit was 2.97 micronGy and with fixed X-ray unit the mean dose was 0.68 micronGy (p<0.01). CONCLUSIONS: The leakage and scattered radiation from hand-held dental radiography was greater than from fixed dental radiography.
Hand ; Head ; Humans ; Radiation Dosage ; Radiography, Dental ; Skull

PURPOSE: To compare the leakage and scattered radiation from hand-held dental X-ray unit with radiation from fixed dental X-ray unit. MATERIALS AND METHODS: For evaluation we used one hand-held dental X-ray unit and Oramatic 558 (Trophy Radiologie, France), a fixed dental X-ray unit. Doses were measured with Unfors Multi-O-Meter 512L at the right and left hand levels of X-ray tube head part for the scattered and leakage radiation when human skull DXTTR III was exposed to both dental X-ray units. And for the leakage radiation only, doses were measured at the immediately right, left, superior and posterior side of the tube head part when air was exposed. Exposure parameters of handheld dental X-ray unit were 70kVp, 3mA , 0.1 second, and of fixed X-ray unit 70kVp, 8mA, 0.45 second. RESULTS: The mean dose at the hand level when human skull DXTTR III was exposed with portable X-ray unit 6.39 micronGy, and the mean dose with fixed X-ray unit 3.03 micronGy (p<0.001). The mean dose at the immediate side of the tube head part when air was exposed with portable X-ray unit was 2.97 micronGy and with fixed X-ray unit the mean dose was 0.68 micronGy (p<0.01). CONCLUSIONS: The leakage and scattered radiation from hand-held dental radiography was greater than from fixed dental radiography.
Hand ; Head ; Humans ; Radiation Dosage ; Radiography, Dental ; Skull

PURPOSE: To compare the copper equivalent values measured at premolar and molar areas in the copper equivalent images of panoramic and intraoral radiographs and to evaluate the possibility of the copper equivalent images of panorama for the assessment the bone density. MATERIALS AND METHODS: Intraoral radiograms at mandibular premolar and molar area and panoramas of 6 human dry skulls were taken with copper-step wedge by Heliodent MD (Siemens Co., Germany) and by Planmeca (PM 2002 CC, Planmeca, Helsinki, Finland) were used for experiment. The copper equivalent values measured at premolar and molar areas in the copper equivalent im ages of panorama and intraoral film were compared. RESULTS: The copper equivalent values were ranged 0.20 mmCu-0.44 mmCu at the molar areas, 0.05 mmCu-0.31 mmCu at the premolar areas on panoramic images. There were no significant differences (p>0.5) between the copper equivalent values on intraoral images and those on panoramic images measured at premolar areas and molar areas respectively. The correlation coefficient between the copper equivalent values on intraoral images and those on panoramic images was respectively 0.8495 at molar areas and 0.6184 at premolar areas. CONCLUSIONS: The copper equivalent images of panorama for the assessment the bone density appeared to be significant at molar area compared with the one of intraoral radiograph.
Bicuspid ; Bone Density ; Copper ; Densitometry ; Humans ; Molar ; Radiography ; Skull