Análise cefalométrica: ortodontistas x radiologistas

Cephalometric analysis is the mensuration of linear and angular measures through demarcation points as distances and lines on teleradiography, and is considered of fundamental importance for diagnosis and orthodontic planning. In this manner, the objective of this research was to compare cephalometric measurements obtained by dentists and radiologists from the analysis of the same radiograph, in a computerized cephalometric analysis program. All research participants marked 18 cephalometric points on a 14-inch notebook computer, as directed by the program itself (Radiocef 2®). From there, they generated 14 cephalometric parameters including skeletal, dental-skeletal, dental and soft tissue. In order to verify the intra-examiner agreement, 10 professionals from each group repeated the marking of the points with a minimum interval of eight days between the two markings. The intra-group variability was calculated based on the coefficients of variation (CV). The comparison between groups was performed using the Student t-test for normally distributed variables, and using the Mann-Whitney test for those with non-normal distribution. In the group of orthodontists, the measurements of Pog and 1-NB, SL, S-Ls Line, S-Li Line and 1.NB showed high internal variability. In the group of radiologists, the same occurred with the values of Pog and 1-NB, S-Ls Line, S-Li Line and 1.NA. In the comparison between groups, all the analyzed linear values and two angular values showed statistically significant differences between radiologists and dentists (p <0.05). According to the results, the interexaminer error in cephalometric analysis requires more attention, but does not come from a specific class of specialists, being either dentists or radiologists.

Iterative reconstruction as a novel method of radiation dose reduction at computed tomography in patients with Crohn's disease

Prior work of our research group, that quantified the alarming levels of radiation dose to patients with Crohn’s disease from medical imaging and the notable shift towards CT imaging making these patients an at risk group, provided context for this work. CT delivers some of the highest doses of ionising radiation in diagnostic radiology. Once a medical imaging examination is deemed justified, there is an onus on the imaging team to endeavour to produce diagnostic quality CT images at the lowest possible radiation dose to that patient. The fundamental limitation with conventional CT raw data reconstruction was the inherent coupling of administered radiation dose with observed image noise – the lower the radiation dose, the noisier the image. The renaissance, rediscovery and refinement of iterative reconstruction removes this limitation allowing either an improvement in image quality without increasing radiation dose or maintenance of image quality at a lower radiation dose compared with traditional image reconstruction. This thesis is fundamentally an exercise in optimisation in clinical CT practice with the objectives of assessment of iterative reconstruction as a method for improvement of image quality in CT, exploration of the associated potential for radiation dose reduction, and development of a new split dose CT protocol with the aim of achieving and validating diagnostic quality submillisiever t CT imaging in patients with Crohn’s disease. In this study, we investigated the interplay of user-selected parameters on radiation dose and image quality in phantoms and cadavers, comparing traditional filtered back projection (FBP) with iterative reconstruction algorithms. This resulted in the development of an optimised, refined and appropriate split dose protocol for CT of the abdomen and pelvis in clinical patients with Crohn’s disease allowing contemporaneous acquisition of both modified and conventional dose CT studies. This novel algorithm was then applied to 50 patients with a suspected acute complication of known Crohn’s disease and the raw data reconstructed with FBP, adaptive statistical iterative reconstruction (ASiR) and model based iterative reconstruction (MBIR). Conventional dose CT images with FBP reconstruction were used as the reference standard with which the modified dose CT images were compared in terms of radiation dose, diagnostic findings and image quality indices. As there are multiple possible user-selected strengths of ASiR available, these were compared in terms of image quality to determine the optimal strength for this modified dose CT protocol. Modified dose CT images with MBIR were also compared with contemporaneous abdominal radiograph, where performed, in terms of diagnostic yield and radiation dose. Finally, attenuation measurements in organs, tissues, etc. with each reconstruction algorithm were compared to assess for preservation of tissue characterisation capabilities. In the phantom and cadaveric models, both forms of iterative reconstruction examined (ASiR and MBIR) were superior to FBP across a wide variety of imaging protocols, with MBIR superior to ASiR in all areas other than reconstruction speed. We established that ASiR appears to work to a target percentage noise reduction whilst MBIR works to a target residual level of absolute noise in the image. Modified dose CT images reconstructed with both ASiR and MBIR were non-inferior to conventional dose CT with FBP in terms of diagnostic findings, despite reduced subjective and objective indices of image quality. Mean dose reductions of 72.9-73.5% were achieved with the modified dose protocol with a mean effective dose of 1.26mSv. MBIR was again demonstrated superior to ASiR in terms of image quality. The overall optimal ASiR strength for the modified dose protocol used in this work is ASiR 80%, as this provides the most favourable balance of peak subjective image quality indices with less objective image noise than the corresponding conventional dose CT images reconstructed with FBP. Despite guidelines to the contrary, abdominal radiographs are still often used in the initial imaging of patients with a suspected complication of Crohn’s disease. We confirmed the superiority of modified dose CT with MBIR over abdominal radiographs at comparable doses in detection of Crohn’s disease and non-Crohn’s disease related findings. Finally, we demonstrated (in phantoms, cadavers and in vivo) that attenuation values do not change significantly across reconstruction algorithms meaning preserved tissue characterisation capabilities with iterative reconstruction. Both adaptive statistical and model based iterative reconstruction algorithms represent feasible methods of facilitating acquisition diagnostic quality CT images of the abdomen and pelvis in patients with Crohn’s disease at markedly reduced radiation doses. Our modified dose CT protocol allows dose savings of up to 73.5% compared with conventional dose CT, meaning submillisievert imaging is possible in many of these patients.

Calcaneus-navicular coalition associated to flatfoot in a child. A case report

Tarsal coalition (a congenital fibrous, cartilaginous or bony connection between two bones) often leads to a flatfoot deformity in children. Usually it presents with recurrent ankle sprains or insidious onset of a painful rigid flatfoot and movement limitation of midtarsal and subtalar joints. Clinical diagnosis is confirmed by X-rays, computed axial tomography and nuclear magnetic resonance. The anteater nose sign is caused by a tubular elongation of the anterior process of the calcaneus that approaches or overlaps the tarsal scaphoid (navicular) and resembles the nose of an anteater on a lateral foot or ankle radiograph. The treatment of this union is primarily symptomatic but if the pain persists must be surgical .

Aspiração de corpo estranho na criança: um perigo escondido

Introdução: A aspiração de corpo estranho (ACE) é uma emergência pediátrica e uma causa importante de morte acidental na criança. A maioria dos casos ocorre com objetos orgânicos e inorgânicos de pequenas dimensões, sobretudo em idade pré-escolar. A ACE cursa com amplo espectro de manifestações e o seu diagnóstico representa muitas vezes um desafio. Caso clínico: Descrevemos o caso clínico de uma criança de dois anos que recorreu ao Serviço de Urgência por tosse, disfonia e disfagia. Ao exame objetivo apresentava acessos de tosse estridulosa, tiragem supra-esternal ligeira e auscultação pulmonar com sibilos inspiratórios/expiratórios e roncos dispersos bilateralmente. A telerradiografia do tórax evidenciava um reforço hilar bilateral, mais notável à direita. A avaliação por Otorrinolaringologia, incluindo a nasolaringofibroscopia, não de- mostrou alterações. A broncoscopia revelou a presença de corpo estranho vegetal condicionando obstrução superior a 50% do lúmen do brônquio principal direito. Conclusão: Pretendemos com este caso salientar a necessidade de manter alto índice de suspeição perante a possibilidade de ACE, pois o atraso no seu reconhecimento condiciona o seu tratamento e o eventual aparecimento de sequelas irreversíveis.

Caso imagiológico

Introdução: A tosse constitui um dos principais motivos de consulta médica e, apesar de na maioria dos casos ser de etiologia vírica ou alérgica, por vezes surgem diagnósticos inesperados. Caso Clínico: Criança do sexo feminino, 19 meses, sem antecedentes relevantes. Recorreu ao Serviço de Urgência por tosse produtiva há 3 semanas e rinorreia serosa, sem febre. Noção materna de dificuldade respiratória e recusa alimentar parcial. À admissão, polipneica, com tiragem subcostal e gemido expiratório. Auscultatoriamente, murmúrio vesicular globalmente diminuído, tempo expiratório aumentado e sibilos dispersos. Analiticamente sem alterações. A radiografia torácica evidenciou volumosa imagem quística no hemitórax direito. A TC to- rácica documentou estômago intratorácico. Foi submetida a laparoscopia que constatou hérnia do hiato paraesofágica. Após Fundoplicatura de Nissen ficou assintomática. Discussão: A hérnia do hiato é rara em idade Pediátrica, tendo sido um achado inesperado no caso clínico descrito. Consideramos assim que, apesar da sua raridade, as anomalias anatómicas devem ser consideradas no diagnóstico diferencial da tosse persistente.

Acute Psychosis as Major Clinical Presentation of Legionnaires’ Disease

We report a case of a 61-year-old woman who presented with acute psychosis as a major manifestation of Legionnaires’ disease in the absence of other neuropsychiatric symptoms. Clinical history revealed dry cough and nausea. Observation showed fever and auscultation crackles in the lower lobe of the right lung. Laboratory testing demonstrated elevated C-reactive protein and lung chest radiograph showed patchy peribronchial and right lower lobe consolidation. Soon after admission, she started producing purulent sputum. Epidemiological data suggested Legionella pneumophila as possible cause of the clinical picture that was confirmed by urinary antigen detection and polymerase chain reaction of the sputum. She was treated with levofloxacin 750 mg/day for 10 days with complete remission of pulmonary and psychiatric symptoms. She has not had further psychotic symptoms.