Frontal Tomography Research Articles

A Novel Occlusographic Analysis for Assessment of Mandibular Narrowing

Accurate evaluation of transverse mandibular dimension is a controversial and rarely addressed topic. Although mandibular narrowing via symphyseal osteotomy and bilateral ramus sagittal split was initially described more than 30 years ago, the development of a simple and effective clinical tool to assess the outcome of such procedures remains elusive. Although many quantitative modalities, such as frontal cephalogram, tomography, and interdental distance measurement, are in current use, each possesses significant liabilities. Prompted by a need for improved accuracy, simplicity, and reliability in the clinical setting, we developed and used a novel occlusographic analysis. The Madjidi occlusographic analysis does not rely on the position or tilt of moveable teeth; therefore, orthodontic changes do not influence quantification of mandibular position. Contours and mandibular relationships of interest are seen clearly, radiation is unnecessary, and occlusographic analysis can be quickly reproduced in the clinical setting using widely available materials. Although the evaluation of transverse mandibular dimension after surgical narrowing is frequently more controversial than accurate, the Madjidi occlusographic analysis is a reliably simple solution to an often complex problem.

Role of different imaging modalities in assessment of temporomandibular joint erosions and osteophytes: a systematic review

To evaluate the ability of different diagnostic imaging techniques for diagnosing the presence of erosions and osteophytes in the temporomandibular joint (TMJ). A systematic search of PubMed, Medline, all Evidence Based Medicine (EBM) reviews, Embase, Web of Sciences and Lilacs identified nine articles that met the selection criteria: some type of TMJ diagnostic imaging, data from autopsy or dry skull TMJs as gold standard, absence of diagnosed systemic arthritis and evaluation of the presence of erosions and/or osteophytes. A hand search of the references of the selected articles was also performed. Selected studies evaluated panoramic imaging (unenhanced and colour-enhanced digital subtraction panoramic imaging), axially corrected sagittal tomography, axially corrected frontal tomography, sagittal MRI, CT, high-resolution ultrasound and cone beam CT (CBCT). Axially corrected sagittal tomography is currently the imaging modality of choice for diagnosing erosions and osteophytes in the TMJ. CT does not seem to add any significant information to what is obtained from axially corrected sagittal tomography. CBCT might prove to be a cost- and radiation dose-effective alternative to axially corrected sagittal tomography. Combining different radiographic techniques is likely to be more accurate in diagnosing erosions and osteophytes in the TMJ than using a single imaging modality. Diagnostic studies that simultaneously evaluate all of the available TMJ imaging technologies are needed.

Organ radiation dose assessment for conventional spiral tomography: a human cadaver study.

The head of a human cadaver was positioned in a Cranex TOME multifunctional unit (Orion Corporation Soredex, Helsinki, Finland) to measure the organ radiation doses after tomographic examinations of the upper and lower edentulous jaw bone. Five consecutive examinations were carried out in the upper and lower anterior jaw regions to cover the entire frontal area, 2 in the upper and lower left premolar regions, and 3 and 4 in the upper and lower left molar regions, respectively. Each examination consisted of 4 slices with a 2 mm slice thickness. Thermoluminescent dosimeter chips were placed in the thyroid gland and bilaterally in the parotid and submandibular glands. Dosimetric measurements were repeated for the different tomographic examinations mentioned above. For spiral tomography in the maxilla, organ doses for both parotid glands were most elevated, while those for the thyroid glands were the lowest. Average doses per examination reached levels of 0.27 mGy for the right (OS) parotid gland with frontal tomography, and 3.89 mGy and 1.67 mGy for the parotid gland at tube-side (TS) for premolar and molar tomography. For the thyroid gland, a minimal dose of < or = 0.004 mGy was noticed for all examinations. For spiral tomography of the frontal area in the mandible, the OS parotid gland received the highest dose (0.77 mGy), while for an analysis of the premolar and molar areas, doses were more elevated for the TS parotid gland (1.22 mGy and 1.72 mGy, respectively). For the TS submandibular gland, organ doses were also raised, with values of 0.39 mGy for frontal, 1.31 mGy for premolar and 1.61 mGy for molar tomography. This study thus indicates that for conventional spiral tomographic examinations in the maxilla and the mandible, radiation doses for the TS submandibular and parotid glands were significantly more elevated than those to the thyroid gland. These values remain however below the organ doses previously reported for spiral CT involving both a full upper or lower jaw.

Radiographic changes in the temporomandibular joint in patients with generalized osteoarthritis and rheumatoid arthritis

This is the first study concerned with radiographic characteristics in patients with generalized osteoarthritis and signs and symptoms of temporomandibular joint involvement. For comparison, patients with rheumatoid arthritis and temporomandibular joint involvement were used. The patient material comprised 20 patients with generalized osteoarthritis (20 joints) and 21 patients with rheumatoid arthritis (21 joints). The radiographic methods were corrected sagittal tomography (hard tissue changes, joint space, and condylar position), frontal tomography (hard tissue changes), and individualized oblique lateral transcranial projections (condylar translation). Sixteen (80%) joints in the group of patients with generalized osteoarthritis and 15 (71%) joints in the group with rheumatoid arthritis revealed structural changes. The condyle was the predominant location. No radiographic criterion was pathognomonic for generalized osteoarthritis or rheumatoid arthritis. However, osteophytes, flattening of the condyle, or a reduced joint space was observed more often in joints with generalized osteoarthritis, whereas erosions in the condyle were more common in joints with rheumatoid arthritis. The radiographic findings in patients with generalized osteoarthritis are more similar to those seen in patients who have the common form of temporomandibular joint osteoarthritis than to those in patients with rheumatoid arthritis.

The contribution of frontal tomography to the diagnosis of temporomandibular joint osteoarthritis.

The contribution of frontal tomography to the diagnosis of temporomandibular joint (TMJ) osteoarthritis has been investigated. Ninety-one patients with clinically defined TMJ disorders were examined by simultaneous lateral and frontal TMJ tomograms taken in the intercuspal position. Abnormal findings were observed on frontal tomograms in 31 joints and suspicious findings in 22 joints. On the other hand, there were 41 joints with abnormal findings and 22 joints with suspicious findings on the lateral tomograms. Suspicious or abnormal findings were found on frontal tomograms alone in 14 joints (7.7%) of 14 patients (15.4%). It is concluded that simultaneous lateral and frontal tomography produces a more accurate radiographic diagnosis of TMJ osteoarthritis.

上顎癌症例のＸ線骨破壊像の検討 単純Ｘ線，断層像とＣＴとの不一致

The detectability of bone destruction is discussed and a comparison is presented of Caldwell's and Waters' views, maxillary tomography and CT scans of 10 patients with maxillary cancer. Destruction of the lateral wall of the maxillary sinus was confirmed in all 10 patients by CT scan, but destruction of the tuber maxillary line (T-M line) could not be seen in Caldwell's and Waters' views in 5 of the patients. As a rule, frontal tomography was helpful in the observation of the orbital base, the median wall of the maxillary sinus and the nasal cavity. However, CT scan was the best method, and accurate with observation of the anterior wall of the maxillary sinus was possible only with axial CT.

Comparison of computed with conventional tomography in the evaluation of temporomandibular joint disease: a study of autopsy specimens.

Autopsy specimens were examined both radiographically and macroscopically to compare direct computed tomography (CT) with conventional tomography (CVT) for their diagnostic yield of the structural bone changes in the temporomandibular joint (TMJ). Fifteen specimens were examined with corrected sagittal and 12 with corrected frontal tomography. Five joints showed bone exposure and/or disc perforation macroscopically and all of them were correctly diagnosed by both CT and CVT (sensitivity 1.0). However, false-positive diagnoses were also made, resulting in values for specificity which were somewhat lower for CT than for CVT. Frontal images did not reveal any additional 'true' findings compared with sagittal CT or CVT. For single areas of the joints the average sensitivity was low, 0.28 for CT and 0.47 for CVT, but the specificity for the joint as a whole was high with both methods (0.91 and 0.94 respectively). We conclude that CVT is superior to CT in the diagnosis of single structural bone changes but comparable for comprehensive diagnosis of TMJ disease.

発声にともなう麻ひ声帯の形状変化に関する画像解析 空気力学的な力の関与について

The development of digital radiography (DR) has made it possible to analyze the contour of the laryngeal soft tissue structures in more detail than the conventional screen-film method. We analyzed the contour of the paralyzed vocal cord during phonation using motion subtraction technique. Forty four patients with unilateral recurrent nerve palsy were examined. The images were obtained by means of frontal tomography of the larynx during quiet inspiration and normal (expiratory) phonation. Tomography during inspiratory phonation was also examined in ten patients who can perform it. The thickness of the slices was 5.0 mm. The authors found that the free margin of the paralyzed vocal cord shifted by the aerodynamic power along the direction of the air flow, i.e. it shifted to the cranial direction during normal phonation and to the caudal during inspiratory phonation. The displacement phenomenon of the paralyzed vocal cord was significantly correlated with the degree of vocal cord atrophy (p less than 0.01). The result would indicate that the aerodynamic power during phonation is one of the factors eliciting the higher position of the paralyzed vocal cord during phonation, in addition to its anatomical displacement due to abduction of the paralyzed arytenoid. This notion should be taken into consideration in selecting the surgical approach for the treatment of unilateral recurrent nerve palsy.

Ｄｉｇｉｔａｌ Ｒａｄｉｏｇｒａｐｈｙによる喉頭のＭｏｔｉｏｎ Ｓｕｂｔｒａｃｔｉｏｎ画像処理

The development of digital radiography (DR) has made it possible to analyze the contour of the laryngeal soft tissue structures in more detail than the conventional screen-film method. The authors first used the DR system for time subtraction of the larynx during inspiration and phonation.The images are acquired by means of frontal tomography of the larynx using the imaging plate during inspiration and phonation separately, and stored into the memory of the DR system. The thickness of the slices is 5.0 mm. Time subtraction between the mask image during inspiration and the live image during phonation is performed using digital processing on CRT. Superimposing the two images at the upper trachea and the thyroid cartilage of the same depth, makes it possible to measure movement of the vocal cord and false vocal cord quantitatively in three dimensions. The authors named this time subtraction as motion subtraction of the larynx.This motion subtraction image can be obtained by on-line digital processing without complicated development technique, but has so high spatial resolution. This image processing seems to be useful in functional radiographic analysis of laryngeal diseases.

Subchondral screw fixation of cervical hip fractures: joint congruence studied with combined arthrography and tomography.

This study was done to determine whether fixation with the Uppsala internal fixation technique into the subchondral bone of the femoral head in the treatment of cervical hip fractures could lead to elevation of the femoral head cartilage. Combined arthrography and frontal tomography of the hip joint in the plane of the screws was performed. The series consisted of 16 patients. In two of the patients, the tips of the screws had penetrated into the cartilage of the femoral head. In the other 14, the internal fixation was technically correct with the tips of the screws in the subchondral bone. In the two hips with the screws penetrating into the cartilage, the cartilage was slightly elevated. In the hips where the screws were in the correct position, no incongruities or deformity in the cartilage could be detected. Combined arthrography and frontal tomography can, therefore, detect elevation of the cartilage of the femoral head. By placing the screws in the immediate subchondral bone, no elevation of the cartilage of the femoral head surface should occur.

„Complex motion” - Tomographie des Sakroiliakalgelenks

To find a better method for diagnosing sacroiliac (SI) joint disease, an anatomical approach was combined with conventional roentgenology, complex motion tomography and computed tomography. Complex motion tomography is suggested as the method of choice in the investigation of the SI-joint. Because of its complex (sinusoidal) form, the dorsal portion of the joint has to be tomographed in frontal projection and the middle and ventral portions in oblique projection. In 56 patients, referred for probable ankylosing spondylitis, 72 SI joints were investigated. Based on plain radiography six and on frontal tomography five SI joints were diagnosed as normal. However, based on oblique tomography 31 joints were diagnosed as normal.

Gallium scanning and tomography in the preoperative evaluation of lung cancer.

Discrepant reports on the utility of gallium scanning in the preoperative evaluation of patients with lung cancer prompted a prospective study of the test. The authors studied 47 patients with lung cancer who underwent preoperative gallium scanning and frontal tomography of the mediastinum. Both tests were found to be most accurate in predicting the presence of mediastinal metastases among patients with squamous cell carcinoma. Both test may help direct surgical planning in patients with known squamous cell carcinoma of the lung.

Radiation dosimetry in multi-film tomography of the maxillary sinuses.

The doses absorbed and energy imparted to facial tissues in hypocyloidal tomography of the maxillary sinuses were measured during a multi-film cassette exposure. Most absorbed doses were below 0.2 mGy, except for frontal tomography in an antero-posterior projection where the dose to the eye lens was 29 mGy. This dose was reduced by a factor of 24 by the use of leaded eyeglasses and by about 100-fold by a postero-anterior projection. Lateral tomography resulted in lower absorbed doses than frontal: the energy imparted was about 10 mJ in the latter compared to 4 mJ in the former.

Tomography as an aid to detect macroscopic changes of the temporomandibular joint. An autopsy study of the aged.

The aim of this study was to evaluate the possibility of detecting macroscopic changes of the temporomandibular joint with the aid of tomographic examination. Forty-four autopsy specimens were examined with corrected sagittal and frontal tomography. The tomograms were evaluated without comparative assessment of the macroscopic appearance. The diagnostic sensitivity, specificity, and predictive values were calculated. Diagnostic accuracy depends on the severity, extent, and localization of the macroscopic changes. All joints with severe and extensive macroscopic changes were identified on tomograms; two thirds of the joints with moderate changes were correctly diagnosed. Macroscopic changes of the condyle were more frequently detected than those of the temporal component. The specificity for single areas of the joints was higher than the sensitivity--that is, normal areas were more easily assessed than areas with changes.

Ｄｉｇｉｔａｌ Ｒａｄｉｏｇｒａｐｈｙのこう頭疾患診断への応用

Fuji Computed Radiography (FCR) is a new system of digital radiography that is based on the latest computer technologies. We applied this FCR system to the X-ray diagnosis of the laryngeal disease. Twenty patients with various laryngeal diseases were evaluated by both FCR frontal tomography and conventional screen-film frontal tomography under the same exposure condition. Both tomograms were then compared on the subject of the clarity of delineation of laryngeal structures.As the result, FCR tomograms revealed the feature of the laryngeal lumen and cartilages more clearly than conventional tomograms. In addition, energy subtraction method, which is one of FCR image processing systems, was presented as a new technical procedure to extinguish cervical spine shadows in plain anteroposterior laryngeal X-photograph. We stress that FCR system is the suitable procedure for X-ray analysis of laryngeal diseases, especially in the region related with the phono-surgery.

Radiation dosimetry in radiology of the temporomandibular joint.

The absorbed doses and energy imparted during conventional radiography and tomography of the temporomandibular joint were examined. Absorbed doses from the lateral-oblique transcranial projection and lateral tomography were low (0.02 to 7 mGy). From the axial projection the thyroid gland and salivary glands received a substantial dose (15 to 54 mGy) which was considerably decreased using an improved design of collimator. Radiation to the lens of the eye for the transmaxillary projection and for frontal tomography was 3 to 8 mGy. This can be reduced by a factor of 25 using lead-glass eye shields. The mean energy imparted from a bilateral examination of the temporomandibular joints using axial projection, four exposures for the transcranial lateral-oblique views, two exposures in the transmaxillary projection and lateral tomography views using a multi-film cassette was 34 mJ. The axial projection accounted for 50% of this figure.

Frontal tomography of articulating temporomandibular joint surfaces.

A variety of radiographic techniques to overcome the limitations imposed by the complex and dense bony anatomy of the TMJ area have been developed and reported over the years. Body section tomography can produce images of the internal hard tissues of the joint with much less interference from superimposing structures. Multiple lateral tomographs of the joint can provide useful diagnostic radiographic coverage, but the many exposures require relatively large accumulated radiation exposure. Frontal TMJ tomography offers one alternative, visualizing the entire anterosuperior surface of the condyle from medial to lateral pole on one film. Existing frontal tomographic methods provide a view of the superior surface, but not of the important anterior articulating surfaces. This project has developed and tested a technique for angulating frontal tomographs of the temporomandibular joint on two axes to visualize the articulating anterosuperior surface of the condyle and posterior slope of the articular eminence.

Efficacy of whole lung tomography in diagnosing metastases from solid tumors in children.

Whole lung, frontal tomography is compared with frontal chest radiography in the diagnosis of pulmonary metastasis in children with cancer. Of 79 patients studied, 65 had a total of 195 routine tomograms. In only 2.7% of studies did tomography yield new information, and in only 1% was an additional lesion visualized. In 27 patients, tomography was performed after an abnormality was seen on the chest radiograph. New information was obtained in 15 (32%) of those 47 studies; additional nodules were identified on six occasions (four metastatic, two inflammatory), but only once was treatment altered. In one study, tomography localized a nodule seen only on a lateral chest radiograph, and in eight studies it excluded metastasis following an abnormal frontal chest radiograph.

Condylar remodeling after occlusal therapy

Seven men and 15 women with TMJ pain dysfunction syndrome were selected. After clinical examination, polytomography of the TMJ was performed in centric occlusion in different planes. Open-mouth projections were also made in three patients, frontal tomography in one patient, and transcranial radiographs in 16 patients. Occlusal analysis was performed on the articulator. Twenty patients showed various patterns of condylar displacement with flattening of the anterior, superior, or posterior condylar walls in 11 patients, including three with arthritic lesions. Therapy included occlusal splints (21 patients), selective grinding (seven patients), prosthodontic rehabilitation (10 patients), and orthodontic treatment (two patients). After therapy, tomographic examination was repeated at intervals of 9 to 44 months. A distinct reshaping of the condyle was seen in seven patients. The new shape tended to be rounded. The three patients with degenerative changes before treatment showed regression of the lesions. No change was seen in condyles which were rounded before therapy.

Computed frontal tomography (CFT) of the orbit using the EMI CT 1010 head scanner.

Frontal tomograms of the orbits can be obtained with the EMI CT 1010 head scanner, retaining the fine matrix (320 X 320) and thin slice options. Only minor modifications are required.