Radiographic manifestations of inoperable primary bronchogenic carcinoma

Bronchogenic carcinoma should be a topic of paramount importance to all who interpret chest radiographs because of its increasing incidence. For several decades the disease has been underestimated in the developing world. A prospective study was carried out on 52 patients (43 males, 9 females) with primary bronchogenic carcinoma at Oncology Teaching Hospital/Medical City-Baghdad from October 2016 to March 2017. All patients had standard plain chest radiographs (postero-anterior, and lateral views). Any abnormality detected was further studied with conventional tomography. The diagnosis was confirmed by histopathology examinations for all patients who were clinically evaluated by other methods of investigations. Most patients had more than one radiological feature which were mainly pulmonary masses, either hilar or peripheral or both at the same time. Other less common features were; mediastinal adenopathy (27%), atelactasis (25%) and pleural effusion (21%). Radiological signs that determine inoperability were evaluated together with other factors that were used as basic principles in the assessment of inoperability. From the total of fifty-two patients; 45 (86.5%) were inoperable radiologically and clinically, and also 4 patients (57%) out of the 7 who underwent thoracotomy were inoperable due to invasion and adhesion to the vessels and other vital structures. The chest radiograph is still important, cheap and available diagnostic procedure in lung cancer, and to decide further management.

The accuracy of ridge mapping procedure in determining the alveolar ridge width

Background: Post-extraction alveolar ridge resorption is unavoidable phenomenon ending with insufficient ridge width. Measuring the physical dimensions of the available bone before implant surgery is an important aspect of diagnosis and treatment planning. Bone height can be calculated from radiographs, while bucco-lingual ridge width can be measured by conventional tomography, CT scanning and ridge mapping. Radiographic techniques have certain disadvantages. Therefore the ridge mapping technique was used as an option for determining alveolar ridge width. The purpose of this study was to compare the validity of alveolar ridge width measurements obtained with ridge mapping technique before surgical flap reflection against direct caliper measurement following surgical exposure of the bone. Materials and Methods: This prospective observational clinical study included 21 patients; 9 males (42.9%) and 12 females (57.1%) with mean age of 40.8. A vacuum formed acrylic stent was fabricated for each subject. The stent provided two buccal/lingual pairs of consistent measurement points to provide a reference of measurement for each implant site located 3 and 6 mm from the crest of alveolar soft tissue. Measurements (n=216) were made at 54 implant sites, the measurements obtained from the two techniques were compared and then accuracy of these methods was assessed. The mean, standard deviation, standard error of mean were calculated and subjected to statistical analysis using Student’s unpaired t- test, values <0.05 were considered statistically significant. Results: There was no statistically significant difference between ridge mapping technique and intra-operative measurement in determining alveolar ridge width. Conclusion: The ridge mapping technique is a useful method in determining alveolar ridge width for its exactitude, low cost, the immediate result and no need of radiation.

Correlative 3D x-ray fluorescence and ptychographic tomography of frozen-hydrated green algae

Accurate knowledge of elemental distributions within biological organisms is critical for understanding their cellular roles. The ability to couple this knowledge with overall cellular architecture in three dimensions (3D) deepens our understanding of cellular chemistry. Using a whole, frozen-hydrated Chlamydomonas reinhardtii cell as an example, we report the development of 3D correlative microscopy through a combination of simultaneous cryogenic x-ray ptychography and x-ray fluorescence microscopy. By taking advantage of a recently developed tomographic reconstruction algorithm, termed GENeralized Fourier Iterative REconstruction (GENFIRE), we produce high-quality 3D maps of the unlabeled alga’s cellular ultrastructure and elemental distributions within the cell. We demonstrate GENFIRE’s ability to outperform conventional tomography algorithms and to further improve the reconstruction quality by refining the experimentally intended tomographic angles. As this method continues to advance with brighter coherent light sources and more efficient data handling, we expect correlative 3D x-ray fluorescence and ptychographic tomography to be a powerful tool for probing a wide range of frozen-hydrated biological specimens, ranging from small prokaryotes such as bacteria, algae, and parasites to large eukaryotes such as mammalian cells, with applications that include understanding cellular responses to environmental stimuli and cell-to-cell interactions.

The Utility of Dual Energy Computed Tomography in Musculoskeletal Imaging

The objective of this article is to review the mechanisms, advantages and disadvantages of dual energy computed tomography (DECT) over conventional tomography (CT) in musculoskeletal imaging as DECT provides additional information about tissue composition and artifact reduction. This provides clinical utility in detection of urate crystals, bone marrow edema, reduction of beam hardening metallic artifact, and ligament and tendon analysis.

Three-Dimensional Tomographic Reconstruction for Microscale Object Modeling

When scanning a relatively high resolution, thick object using conventional computed tomography (CT), the scanning axis of the X-ray gantry and detector is approximately perpendicular to the rotation axis of the sample. However, the inner interconnections in flat 3D devices are not reconstructed correctly in regular circular CT. In this paper, we focus on 3D tomographic reconstruction of inner interconnections by CT with particular attention to off-centered circular trajectory CT. However, in off-centered circular trajectory CT, the limited tilting angles of projections result in a missing wedge artifact because the object cannot usually be tilted beyond the limit and the data in the remaining projections are not obtained. Therefore, to alleviate missing wedge artifacts, we propose a reconstruction scheme of combining by filtered back projection (FBP) and constraint-based total variation minimization (c-TVM). In the c-TVM method, the artifact of missing wedge is minimized and the reconstructed region is suppressed with high frequency details while leaving the boundaries between homogeneous regions. In our experiments, the CT system obtained the projected images from a rotating sample using a fixed-mounted X-ray source and detector. We acquired 400 rotational projection images of a vertical connection in an off-centered circular trajectory with 30° tilting angles. We then reconstructed the aligned 3D views of the sample. Finally, we demonstrated that the proposed FBP and c-TVM combination with iterative processing yields a superior 3D reconstruction model to conventional tomography.

Tomografía: más allá de las aplicaciones médicas

Tomography using CT scans and MRI scans is now well-known as a medical diagnostic tool which allows for detection of tumors and other abnormalities in a noninvasive way, providing very detailed images of the inside of the body using low dosage X-rays and magnetic fields. They have both also been used for determination of material defects in moderate size objects. In medical and other applications they complement conventional tomography. There are many situations where one wants to monitor the electrical conductivity of different portions of an object, for instance, to find out whether a metal object, possibly large, has invisible cracks. This kind of tomography, usually called Electrical Impedance Tomography or EIT, has also medical applications like monitoring of blood flow. While CT and MRI are related to Euclidean geometry, EIT is closely related to hyperbolic geometry. A question that has arisen in the recent past is whether there is similar "topographic" method to monitor the "health" of networks. Our objective is to explain how EIT ideas can in fact effectively be used in this context.

TOMOGRAFIA COMPUTADORIZADA: VANTAGENS SOBRE A RADIOGRAFIA PANORÂMICA NA AVALIAÇÃO DE TERCEIROS MOLARES INFERIORES INCLUSOS

Tomografia Computadorizada: vantagens sobre a Radiografia Panorâmica na avaliação de terceiros molares inferiores inclusos. A cirurgia dos terceiros molares inferiores retidos pode levar a alterações sensoriais importantes, devido a trauma no nervo alveolar inferior, o qual no seu trajeto, apresenta relação intra-óssea importante com as raízes dos molares. A relação entre os ápices do terceiro molar e o canal mandibular deve ser previamente identificada à intervenção cirúrgica. O presente trabalho tem por objetivo a comparação das imagens, da relação dos terceiros molares inferiores retidos com o canal mandibular, fornecidas por radiografias panorâmicas (RP) e por tomografias computadorizadas (TC). Metodologia: Comparação de radiografias panorâmicas e suas respectivas TC, levando em consideração a relação de proximidade dos ápices dentários com o canal mandibular. Resultados: Das RP avaliadas, todas apresentaram imagem de sobreposição do canal mandibular, e uma delas, também sugeriu trajeto interradicular do mesmo. Na TC comprovou-se tridimensionalmente relação de proximidade dos mesmos e em um caso, descartou-se a possibilidade de um trajeto interradicular do canal mandibular. Conclusão: Pelo material analisado, sugere-se que a TC mostra-se superior no diagnóstico e planejamento cirúrgico de terceiros molares inclusos. Palavras-Chave: Tomografia; Radiografia Panorâmica; Nervo Mandibular Referências Bibliográficas 1. DÍAZ-TORRES, M. J. et al. Fatores clínicos y radiológicos de “verdadera relación” entre el nervio dentário y el tercer molar. Revista Española de Cirurgia Oral y Maxillofacial, v. XII, n. 2, p. 51-57, 1990.2. FREDERIKSEN, N.L.; Diagnostic imaging in dental implantology. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontics. v.80, 540-554, 1995.3. KINGLE, B.; PETERSSON, A.; MALY, P. Location of the mandibular canal: comparison of Macroscopic findings, conventional radiography, and computed tomography. Int J Oral Maxillofac Implants. v. 4, p. 327-332, 1989.4. LINDH, C.; PETERSON, A. Radiologic examination for location the mandibular canal: A comparision between panoramic radiography and conventional tomography. The International Journal of Oral & Maxillofacial Implants. V. 4, n. 3, p.249-253, 1989.5. SINN, D. P.; KARAS, N. D. Radiographic evaluation of facial injuries. In: FONSECA, R. J.; WALKER, R. V. Oral and Maxillofacial Trauma. 2. ed. Saunders Company, 1997. p. 391-418.6. GRAZIANI, Mario. Cirurgia bucomaxilofacial. 8. ed. Rio de Janeiro: Guanabara Koogan, c1995.7. GOMES, A. C. et al. Estudo das lesões nervosas após cirurgia dos terceiros molares inferiores retidos. Dissertação de Mestrado em odontologia – Faculdade de Odontologia de Pernambuco – Camaragibe-Pe, 2001. 123 p.8. FÉLEZ-GUTIÉRREZ, J. et al. Las lesiones Del nervio dentario inferior en el tratamiento quirúrgico del tercer molar inferior retenido: aspectos radiológicos, prognósticos y preventivos. Archivos de Odontoestomatología, v. 13, n. 2, p. 73-83, 1997.9. KINGLE, B.; PETERSSON, A.; MALY, P. Location of the mandibular canal: comparison of macroscopic findings, conventional radiography, and computedtomography. Int J Oral Maxillofac Implants, v. 4, p. 327-332, 1989.10. RUD, J. Third molar surgery: relationship of root to mandibular canal and injuries to inferior dental nerve. Tandlaegebladet, v. 87, n. 18, p. 619-630, 1983.