OBJECTIVE: The objective of the present study is to analyze the optimization of fluoroscopic image quality and patient entrance surface air kerma rate in interventional radiology procedures, utilizing a phantom adapted for fluoroscopy. MATERIALS AND METHODS: The authors utilized a phantom developed for evaluating conventional radiological images adapted for fluoroscopy through the addition of two catheters with different diameters, both of them utilized in interventional radiology. The patient entrance surface air kerma rate was determined with the aid of this phantom. RESULTS: The evaluation of technical parameters for different exposure modes of a digital fluoroscopic imaging system has allowed the determination of the air kerma rate, enabling the optimization of the image quality in interventional procedures. The decrease in the patient entrance surface air kerma rate may achieve 67%. CONCLUSION: The optimization of fluoroscopic image quality achieved with a phantom allows reducing the patient entrance surface air kerma with no significant loss of diagnostic performance.

Keywords: Images optimization, Fluoroscopy, Phantom, Dose reduction

OBJECTIVE: The present paper describes the implementation and evaluation of a medical images management system with content-based retrieval support (PACS-CBIR) integrating modules focused on images acquisition, storage and distribution, and text retrieval by keyword and images retrieval by similarity. MATERIALS AND METHODS: Internet-compatible technologies were utilized for the system implementation with freeware, and C++, PHP and Java languages on a Linux platform. There is a DICOM-compatible image management module and two query modules, one of them based on text and the other on similarity of image texture attributes. RESULTS: Results demonstrate an appropriate images management and storage, and that the images retrieval time, always < 15 sec, was found to be good by users. The evaluation of retrieval by similarity has demonstrated that the selected images extractor allowed the sorting of images according to anatomical areas. CONCLUSION: Based on these results, one can conclude that the PACS-CBIR implementation is feasible. The system has demonstrated to be DICOM-compatible, and that it can be integrated with the local information system. The similar images retrieval functionality can be enhanced by the introduction of further descriptors.

Keywords: CBIR, PACS, DICOM, Medical images, Health information system

Currently, computed tomography is the method of choice for assessment of paranasal sinuses, nasal fossae and their anatomical variations. Presumably, these variations may induce osteal obstruction, preventing mucus drainage and predisposing to chronic rhinosinusitis. However, this concept is still controversial and the presence of any anatomic variation does not necessarily establish an etiology for rhinosinusitis. Among three subtypes of concha bullosa, just the bulbous type seems to be strongly associated with symptoms. Size and obliteration of osteomeatal complex drainage pathways may be relevant as well. Variations and tomographic signs of sinusal disease occurring on the same side reinforce the likelihood of interference with the mucus drainage process. Computed tomography offers detailed study of anatomical variations and is an invaluable tool for managing clinical decisions and planning surgical strategies. Imaging assessment must be based on identification of variants, definition of their dimensions, as well as on their association with obstruction of drainage ostia and tomographic signs of sinus disease.

Keywords: Anatomical variations, Paranasal sinuses, Sinusitis, Computed tomography

OBJECTIVE: To implement a protocol for correction of images acquired by videofluoroscopy based on the mathematical model described by Baltzopoulos (1995) and to evaluate the magnitude of error in the linear and non-linear calibration methods. MATERIALS AND METHODS: The images were acquired using a Axion Siemens Iconos R100 videofluoroscope from one individual during knee extension exercise. A non-linear calibration pattern was used for the correction of the images. Data was processed using a Silicon Graphics 320 capture plate and subsequently analyzed using the Matlab software. RESULTS: In order to demonstrate the method's applicability, the deformation of the patellar ligament was evaluated. The use of a linear calibration pattern produced a maximum error of 0.086 mm, while the non-linear calibration pattern reached a maximum value of 0.019 mm. According to the mean error, the linear calibration was 0.024 mm, and the non-linear presented a value of 0.007 mm. CONCLUSION: The results show the need to use a non-linear calibration procedure.

Keywords: Videofluoroscopy, Images calibration, Patellar ligament, Knee

We present the preliminary results of testing and acceptance of a method for displaying medical images that employs simple computer freewares that can be run in unsophisticated computational platforms, which are commonly underutilized. This method allows easy and accessible visualization, printing, documenting, archiving, consulting and electronic transmission of a wide range of medical images without the need of expensive, complex and difficult to learn softwares.

Keywords: Medical images, Freeware, Ultrasound

OBJECTIVE: To present the process of implementation of toolkits for visualization of medical images using DICOM and to review the basis and characteristics of this protocol. In this paper we present a VDTApplication for visualization of local and remote images, and a VDTApplet that allows the visualization of images on a web browser. MATERIALS AND METHODS: The toolkits were implemented using Java programming language. For the development of this toolkit we considered the different version of the DICOM protocol, creating a generic system capable of reading and opening images generated by different modalities of different manufacturers. The tools were evaluated qualitatively by doctors taking into account the system's interface, image quality and image adjustment. RESULTS: The evaluation score ranged from 1 (very poor ) to 5 (very good) for each item, with the following results: 5 for system interface, 4 for image quality and 3 for the image adjustment. Based on the scores obtained we concluded that the tools can be considered good. CONCLUSION: These results allowed us to conclude that these tools are practical, user friendly and should be added to the PACS (picture archiving and communication system) of "Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto - Universidade de São Paulo", Ribeirão Preto, SP, Brazil.

Keywords: Medical images, DICOM, Filmless radiology, Medical images visualization

The knowledge of meniscal anatomic variants and of the normal perimeniscal structures is essential to understand magnetic resonance imaging studies of the knee, both for the diagnosis of meniscal lesions and to avoid potential interpretation pitfalls. The present article reviews anatomic variants that change the size, shape and stability of the menisci, including the different types of discoid menisci, other less frequent meniscal malformations and the meniscal ossicle. Additionally, the anatomy of perimeniscal structures, particularly those including the meniscocapsular, intermeniscal, meniscofemoral ligaments and other menisco-ligamentous structures is reviewed.

Keywords: Knee; Discoid meniscus; Anatomic variants; Magnetic resonance imaging.

Multislice computed tomography is currently the imaging modality of choice for evaluating paranasal sinuses and adjacent structures. Such a method has been increasingly utilized in the assessment of anatomical variations, allowing their accurate identification with high anatomical details. Some anatomical variations may predispose to sinusal diseases, constituting areas of high risk for injuries and complications during surgical procedures. Therefore, the recognition of such variations is critical in the preoperative evaluation for endoscopic surgery.

Keywords: Multislice computed tomography; Paranasal sinuses; Anatomical variations.

Objetivo: A principal utilidade da tomografia por emissão de pósitrons com 18-fluordeoxiglicose (FDG-PET) está no estadiamento do câncer de pulmão. Porém, ela também pode ser utilizada para diferenciar lesões pulmonares indeterminadas, mas seu impacto na ressecção cirúrgica de lesões benignas é desconhecido. O objetivo deste estudo foi comparar a prevalência de lesões benignas em toracotomias feitas por suspeição de câncer de pulmão, antes e após a introdução do FDG-PET, em um centro de referência de cirurgia torácica. Materiais e Métodos: Os autores analisaram, prospectivamente, uma base de dados cirúrgicos de todos os pacientes consecutivos submetidos a toracotomia por câncer de pulmão suspeito ou comprovado e compararam a prevalência de lesões benignas em dois grupos ao longo de dois anos consecutivos, respectivamente antes (grupo I) e depois (grupo II) da introdução da FDG-PET. Resultados: Ressecção cirúrgica foi feita em 1.233 pacientes durante o período do estudo. A prevalência de lesões benignas na cirurgia nos grupos I e II foi similar (44/626 e 41/607, ambas correspondendo a 7%), e também no grupo II, entre aqueles submetidos a FDG-PET e os restantes (21/301 e 20/306 respectivamente, ambos correspondendo a 7%). No grupo II, dos 21 pacientes com lesões benignas submetidos a FDG-PET, 19 tiveram um estudo falso-positivo (valor médio padrão de captação 5.3 [faixa 2.6–12.7]). Desses, respectivamente 13 e 4 pacientes tiveram broncoscopia não diagnóstica e biópsia transtorácica percutânea de pulmão antes da toracotomia. Não houve diferença na proporção de lesões benignas diferentes ressecadas entre o grupo I e aqueles submetidos a FDG-PET no grupo II. Conclusão: A introdução da FDG-PET não alterou a proporção de pacientes submetidos a toracotomia por lesões benignas, principalmente devido à avidez pelo isótopo de algumas lesões não malignas. Tais resultados falsos-positivos devem ser considerados nos casos em que se contempla a possibilidade de ressecção cirúrgica em pacientes com câncer de pulmão não confirmado.

Keywords: Tomografia por emissão de pósitrons; Tomografia computadorizada; Pulmão – lesões benignas ou congênitas; Câncer de pulmão – diagnóstico e estadiamento; Câncer de pulmão – cirurgia.

Objetivo: Avaliar a percepção de médicos residentes em radiologia de 4º ano sobre as melhores modalidades de imagem na investigação de neoplasias e trauma. Materiais e Métodos: Vinte e sete médicos residentes de 4º ano de quatro programas de residência em radiologia americanos participaram do estudo. Aos participantes foi perguntado sobre a melhor modalidade de imagem para se avaliar o cérebro e a coluna vertebral, pulmões, abdome e o sistema musculoesquelético. As modalidades de imagem disponíveis foram: RM, TC, ultrassonografia, PET e radiografia simples. Todos os achados foram comparados com os Critérios de Adequação de Exames de Imagem e Radioterapia do ACR. Resultados: A RM foi escolhida como melhor modalidade de imagem para se avaliar neoplasias encefálicas, espinhais, abdominais e musculoesqueléticas por 96,3%, 100%, 70,4% e 63% dos residentes, respectivamente. A TC foi escolhida por 88,9% dos residentes para avaliar neoplasias pulmonares. A modalidade de imagem ótima para se avaliar trauma foi a TC para lesões encefálicas (100%), espinhais (92,6%), pulmonares (96,3%), abdominais (92,6%) e grandes lesões traumáticas musculoesqueléticas (74,1%); a RM foi escolhida para lesões esportivas (96,3%). Observou-se concordância com os critérios de adequação do ACR. Conclusão: Houve concordância entre a percepção dos residentes sobre as melhores modalidades de imagem para avaliação de neoplasias e trauma e os critérios de adequação do ACR.

Keywords: Formação de residentes; Educação médica; Modalidades de imagem.

Raspberry Pi is a low-cost computer created with educational purposes. It uses Linux and, most of times, freeware applications, particularly a software for viewing DICOM images. With an external monitor, the supported resolution (1920 × 1200 pixels) allows for the set up of simple viewing workstations at a reduced cost.

Keywords: Raspberry Pi; DICOM; Images; Viewing; Low cost.

OBJECTIVE: To compare the diagnostic performance of the three-dimensional turbo spin-echo (3D TSE) magnetic resonance imaging (MRI) technique with the performance of the standard two-dimensional turbo spin-echo (2D TSE) protocol at 1.5 T, in the detection of meniscal and ligament tears. MATERIALS AND METHODS: Thirty-eight patients were imaged twice, first with a standard multiplanar 2D TSE MR technique, and then with a 3D TSE technique, both in the same 1.5 T MRI scanner. The patients underwent knee arthroscopy within the first three days after the MRI. Using arthroscopy as the reference standard, we determined the diagnostic performance and agreement. RESULTS: For detecting anterior cruciate ligament tears, the 3D TSE and routine 2D TSE techniques showed similar values for sensitivity (93% and 93%, respectively) and specificity (80% and 85%, respectively). For detecting medial meniscal tears, the two techniques also had similar sensitivity (85% and 83%, respectively) and specificity (68% and 71%, respectively). In addition, for detecting lateral meniscal tears, the two techniques had similar sensitivity (58% and 54%, respectively) and specificity (82% and 92%, respectively). There was a substantial to almost perfect intraobserver and interobserver agreement when comparing the readings for both techniques. CONCLUSION: The 3D TSE technique has a diagnostic performance similar to that of the routine 2D TSE protocol for detecting meniscal and anterior cruciate ligament tears at 1.5 T, with the advantage of faster acquisition.

Keywords: Knee; Menisci; Anterior cruciate ligament; Magnetic resonance imaging; Arthroscopy.

OBJECTIVE: To determine whether dual-energy computed tomography (DECT) of the chest can be performed at a reduced radiation dose, with an emphasis on images generated with post-processing techniques. MATERIALS AND METHODS: In 21 patients undergoing DECT of the chest in a dual-source scanner, an additional image series was acquired at a reduced radiation dose. Four thoracic radiologists assessed both image series for image quality, normal thoracic structures, as well as pulmonary and mediastinal abnormalities, on virtual monochromatic images at 40 keV and 60 keV. Data were analyzed with Student’s t-test, kappa statistics, analysis of variance, and the Wilcoxon signed-rank test. RESULTS: The overall image quality of 60 keV virtual monochromatic images at a reduced radiation dose was considered optimal in all patients, and no abnormalities were missed. Contrast enhancement and lesion detection performance were comparable between reduced-dose images at 40 keV and standard-of-care images at 60 keV. The intraobserver and interobserver agreement were both good. The mean volumetric CT dose index (CTDIvol), size-specific dose estimate (SSDE), dose-length product (DLP), and effective dose (ED) for reduced-dose DECT were 3.0 ± 0.6 mGy, 4.0 ± 0.6 mGy, 107 ± 30 mGy.cm, and 1.5 ± 0.4 mSv, respectively. CONCLUSION: DECT of the chest can be performed at a reduced radiation dose (CTDIvol < 3 mGy) without loss of diagnostic information.

Keywords: Radiation dose reduction; Dual energy computed tomography; Monochromatic images.

As they are asymptomatic or have a nonspecific, anatomical variations of the ribs are usually detected as incidental findings on imaging studies. They may be isolated changes or can be related to anomalies or clinical syndromes. Such variations are easily overlooked on conventional radiography and computed tomography if they are not actively investigated, mainly because most indications for a chest X-ray studies aim to evaluate the lung parenchyma and mediastinal structures. The objective of this pictorial essay was to use multislice computed tomography images to illustrate the imaging aspects of the main anatomical variations and congenital anomalies of the ribs.

Keywords: Ribs; Anatomical variation; Multislice computed tomography.

Os nervos cranianos representam extensões das estruturas funcionais do cérebro que cruzam a cabeça e o pescoço. Eles estão ligados a diferentes estruturas cranianas e se relacionam com diversas doenças. Uma compreensão profunda de sua complexa anatomia e aparência normal de imagem permite ao examinador identificar e caracterizar com mais precisão as anormalidades. A ressonância magnética com contraste é uma importante ferramenta para avaliar essas estruturas, especialmente as sequências tridimensionais de precessão livre de estado estacionário, que proporcionam alta resolução espacial e de partes moles, apesar da fina espessura dos nervos cranianos. Na maioria dos casos, os achados de imagem são inespecíficos, e uma anamnese completa, exame físico dirigido e testes laboratoriais são necessários para estreitar o diagnóstico diferencial. Este ensaio iconográfico ilustra e discute doenças congênitas, traumáticas e vasculares dos nervos cranianos, mostrando imagens em uma abordagem fisiopatológica.

Keywords: Neuroimagem/métodos; Radiologia/métodos; Ressonância magnética/métodos; Nervos cranianos/diagnóstico por imagem.