Conventional Linear Tomography Research Articles

Tomografía simultánea multipelícula

A conventional linear tomography technique, which by using a single tomographic exposure, can record layers of the body using multifilm cassette.

CONVENTIONAL LINEAR TOMOGRAPHY IMAGING FOR MANDIBULAR IMPLANTS TREATMENT

Radiographic examination has a very important role in dental implant treatment, including preoperative planning and intraoperative and postoperative assessment. In preoperative planning, radiographic examination has an ability to visualize critical anatomic organs such as mandibular formaen, mandibular canals, and mental foramen, which will guide the choice of implant length, diameter, and position. Besides, it also can reveal variation of quality of the jawbone. Radiographic examination for postoperative assessment of dental implant is usually addressed for evaluation of implant position. Development and application modern imaging modalities in dento-maxillofacial radiology have very important role for better accuracy and more comprehensive dental implant treatment. One of modern radiographic imaging techniques for this purpose is conventional linear tomography. This modality yields visualization of bone quality and quantity in high detail and accuracy, including bone condition in buccal-lingual dimension. Thus the choice of implant type, shape, and size can be obtained precisely and furthermore reducing iatrogenic damage of critical anatomic organ Radiation dose of conventional linear tomography is relatively low compared with other modern imaging modalities such as CT scan, besides that it also has lower cost so it has beneficial economic point. However, for a certain case and condition, there will be more need for combining conventional linear tomography with other techniques, such as the panoramic and periapical technique.

Mild, Moderate, and Severe Forms of Allergic Bronchopulmonary Aspergillosis: A Clinical and Serologic Evaluation

Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity disorder induced by Aspergillus species colonizing the bronchial tree. There are patients with asthma who fulfill the diagnostic criteria of ABPA by serologic evaluation (specific IgE/IgG to Aspergillus fumigatus), bronchography, CT, and or conventional linear tomography. To identify different forms of ABPA based on various diagnostic criteria. Eighteen patients with asthma fulfilling the criteria of ABPA were evaluated in the present study. Six patients each received a diagnosis of ABPA serologic positive (ABPA-S), ABPA with central bronchiectasis (ABPA-CB), and ABPA with central bronchiectasis and other radiologic features (ABPA-CB-ORF). The spirometric changes in the ABPA-S group (group 1) were mild, in the ABPA-CB group (group 2) were moderate, and in the ABPA-CB-ORF group (group 3) were severe. Absolute eosinophil count was raised in each group but was maximum (1,233 micro L) in severe form of disease (group 3). Specific IgE against A fumigatus was raised in each group, and the maximum was 47.91 IU/mL in ABPA-CB-ORF. CT scan findings of the ABPA-S group were normal without central bronchiectasis. The exacerbation in symptoms was maximum in group 3 compared to other groups. The present observations suggest that ABPA includes mild (ABPA-S), moderate (ABPA-CB), and severe (ABPA-CB-ORF) forms of disease. It is recommended, therefore, that the disease should be diagnosed early, treated at the mild form of disease (ABPA-S), and prevented from leading to ABPA-CB or ABPA-CB-ORF.

Conventional linear tomography: Protocol for assessing endosseous implant sites

Proper implant dimension and implant site selection are two major factors that affect the eventual prosthodontic rehabilitation and long-term serviceability of the implant and prosthesis. Conventional linear tomography permits accurate measurements and assessment of available bone for both factors. A protocol for the use of conventional linear tomography for diagnostic assessment, evaluation of proposed implant sites, and the selection of proper implant type and dimension is presented.

Sternoclavicular joint disease in psoriatic arthritis.

The radiological and tomographic aspects of the sternoclavicular joint were examined in 10 patients with psoriatic arthritis to evaluate better how this joint was affected using different radiological techniques. Imaging of the sternoclavicular joint showed that computed tomography provides a better visualisation of erosions, subchondral cysts, and sclerosis than standard radiography and conventional linear tomography.

CT evaluation for pulmonary metastases in patients with extrathoracic malignancy.

Computed tomography (CT) is clearly more sensitive than chest radiography or conventional linear tomography in the detection of pulmonary metastases. Routine chest CT scans may reveal peripheral nodules as small as 2-3 mm, and high-resolution CT may demonstrate lymphangitic carcinomatosis. Specificity remains a problem, but attention to clinical factors, such as the type of extrathoracic malignancy (ETM), epidemiology, patient age, and prior treatment, should be of assistance. CT is useful in the evaluation of an apparent solitary pulmonary nodule or an equivocal radiographic finding. For single or multiple nodules, CT is essential for planning invasive procedures such as biopsy or surgical resection. Routine CT scanning to screen for occult metastases is indicated only for patients with ETMs that have a high propensity for metastasizing to the lungs and for which detection of pulmonary metastases would influence therapy--bone and soft-tissue sarcomas, most pediatric tumors, choriocarcinoma, nonseminomatous testicular carcinoma, and possibly advanced melanoma. Future large prospective studies evaluating individual malignancies are needed to assess the impact on long-term survival of early detection of pulmonary metastases with CT.

Detection of pulmonary metastases in patients with osteogenic and soft-tissue sarcomas: the superiority of CT scans compared with conventional linear tomograms using dynamic analysis.

A prospective serial evaluation in 19 patients with soft-tissue and osteogenic sarcomas was performed to determine whether computerized tomography (CT) or conventional linear tomography (LT) detected pulmonary metastases earlier. Analysis of the metastatic nodules was performed radiographically with histologic confirmation by obtaining serial CTs and LTs followed by metastasectomy. Nodules were classified as stable, growing, or developing and by detection on CT and/or LT. CT was the first positive study in a significantly greater number of patients (13 CT, 1 LT; P less than .005), and CT detected the nodules earlier than LT (56 CT first v 7 LT first; P less than .0001). Ninety of 166 nodules resected were detected by CT, LT, or both (54%). The median size of metastatic nodules documented at surgical exploration and first detected by CT was significantly smaller than that first detected by LT (7.6 mm for CT v 13.2 mm for LT; P less than .05). Of 55 histologically documented metastases detected initially either by CT or LT, CT was markedly superior to LT with 50 (91%) first detected only by CT (P less than .001). These data reveal that CT detects more pulmonary metastases earlier than LT and that developing or growing nodules in patients with sarcomas are usually metastases. Decisions regarding metastasis resection in sarcoma patients, therefore, should be based primarily on CT findings.

Self-masking subtraction tomosynthesis.

The authors tested the image quality and dose savings of self-masking subtraction tomosynthesis (SST), which combines digital tomosynthesis with subtraction of a blurred self-mask. High-quality images of the inner ear of a head phantom were obtained at moderate dose savings. Although they were taken with linear motion, they did not exhibit the streaking due to off-fulcrum objects that is characteristic of conventional linear tomography. SST could reduce patient dose by a factor of at least 12 in examinations of the inner ear, and the mechanical aspects can be implemented with moderate modifications of existing instrumentation.

The posterior pleural reflections.

The posterior mediastinal pleural reflections, which contribute to the formation of the paraspinal and paraaortic lines, were studied by conventional linear tomography, computed tomography (CT), and photodensitometry in eight normal patients; these were compared with other patients with known or suspected abnormal features. The correlated evidence indicates that these lines do not depict anatomic structures as traditionally conceived, but instead represent optical phenomena--Mach bands--formed as a result of the particular anatomic shape, rather than tissue composition, of the lung-mediastinal interface. Consequently, a line may be identified as normal, on plain radiography, in the presence of either a normal or a pathologic posterior mediastinum or pleura. The determination of normalcy cannot be made solely on the basis of the appearance of these lines; CT is the only reliable method for this differentiation.

Evaluation of computed tomography in the detection of pulmonary metastases.A prospective study

Conventional linear x-ray tomography is often used to search for pulmonary metastases but tends to underestimate extent of disease when compared with operative findings. In a prospective study, operative findings were correlated with computed axial tomography and conventional linear tomography performed on 25 patients with a history of extrathoracic malignancy and pulmonary nodules. Computed tomography detected 69 nodules of which 31 proved to be metastases. Conventional linear tomography detected 38 nodules of which 25 were metastases. Of the 54 resected nodules measuring greater than 3 mm, computed tomography detected 42; whereas conventional tomography detected 32. Only six of the 31 additional nodules (20%) detected by computed tomography and not by conventional tomography proved to be metastases. These results suggest that computed tomography is more sensitive than conventional tomography in detecting small pulmonary nodules; however, there is diminished specificity in identifying metastatic nodules.