RESUMO
Four standard radiation qualities (from RQA 3 to RQA 9) were used to compare the imaging performance of a computed radiography (CR) system (general purpose and high resolution phosphor plates of a Kodak CR 9000 system), a selenium-based direct flat panel detector (Kodak Direct View DR 9000), and a conventional screen-film system (Kodak T-MAT L/RA film with a 3M Trimax Regular screen of speed 400) in conventional radiography. Reference exposure levels were chosen according to the manufacturer's recommendations to be representative of clinical practice (exposure index of 1700 for digital systems and a film optical density of 1.4). With the exception of the RQA 3 beam quality, the exposure levels needed to produce a mean digital signal of 1700 were higher than those needed to obtain a mean film optical density of 1.4. In spite of intense developments in the field of digital detectors, screen-film systems are still very efficient detectors for most of the beam qualities used in radiology. An important outcome of this study is the behavior of the detective quantum efficiency of the digital radiography (DR) system as a function of beam energy. The practice of users to increase beam energy when switching from a screen-film system to a CR system, in order to improve the compromise between patient dose and image quality, might not be appropriate when switching from screen-film to selenium-based DR systems.
Assuntos
Intensificação de Imagem Radiográfica/instrumentação , Interpretação de Imagem Radiográfica Assistida por Computador/instrumentação , Tomografia Computadorizada por Raios X/instrumentação , Ecrans Intensificadores para Raios X , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Three standard radiation qualities (RQA 3, RQA 5 and RQA 9) and two screens, Kodak Lanex Regular and Insight Skeletal, were used to compare the imaging performance and dose requirements of the new Kodak Hyper Speed G and the current Kodak T-MAT G/RA medical x-ray films. The noise equivalent quanta (NEQ) and detective quantum efficiencies (DQE) of the four screen-film combinations were measured at three gross optical densities and compared with the characteristics for the Kodak CR 9000 system with GP (general purpose) and HR (high resolution) phosphor plates. The new Hyper Speed G film has double the intrinsic sensitivity of the T-MAT G/RA film and a higher contrast in the high optical density range for comparable exposure latitude. By providing both high sensitivity and high spatial resolution, the new film significantly improves the compromise between dose and image quality. As expected, the new film has a higher noise level and a lower signal-to-noise ratio than the standard film, although in the high frequency range this is compensated for by a better resolution, giving better DQE results--especially at high optical density. Both screen-film systems outperform the phosphor plates in terms of MTF and DQE for standard imaging conditions (Regular screen at RQA 5 and RQA 9 beam qualities). At low energy (RQA 3), the CR system has a comparable low-frequency DQE to screen-film systems when used with a fine screen at low and middle optical densities, and a superior low-frequency DQE at high optical density.
Assuntos
Interpretação de Imagem Radiográfica Assistida por Computador , Filme para Raios X , Ecrans Intensificadores para Raios XRESUMO
This work compares the detector performance and image quality of the new Kodak Min-R EV mammography screen-film system with the Fuji CR Profect detector and with other current mammography screen-film systems from Agfa, Fuji and Kodak. Basic image quality parameters (MTF, NPS, NEQ and DQE) were evaluated for a 28 kV Mo/Mo (HVL = 0.646 mm Al) beam using different mAs exposure settings. Compared with other screen-film systems, the new Kodak Min-R EV detector has the highest contrast and a low intrinsic noise level, giving better NEQ and DQE results, especially at high optical density. Thus, the properties of the new mammography film approach those of a fine mammography detector, especially at low frequency range. Screen-film systems provide the best resolution. The presampling MTF of the digital detector has a value of 15% at the Nyquist frequency and, due to the spread size of the laser beam, the use of a smaller pixel size would not permit a significant improvement of the detector resolution. The dual collection reading technology increases significantly the low frequency DQE of the Fuji CR system that can at present compete with the most efficient mammography screen-film systems.
Assuntos
Mamografia/instrumentação , Algoritmos , Processamento de Imagem Assistida por Computador , Mamografia/métodos , Imagens de Fantasmas , Software , Filme para Raios XRESUMO
UNLABELLED: Undifferentiated sarcoma of the liver is a rare primary tumor of childhood: only about 150 cases have been reported in the literature. CASE-REPORT: A 10 year-old girl was admitted because of diarrhea and weight loss. Sonography, then CT-scan and MRI showed a large tumor of the liver. COMMENTS: In the differential diagnosis of primary liver tumors in children, one should think about undifferentiated sarcoma of the liver, especially if imaging shows haemorrhagic foci and if sonography and CT/MRI display a discordant appearance. Survival has improved in the last decade due to agressive surgery and intensive chemotherapy.
Assuntos
Neoplasias Hepáticas/patologia , Sarcoma/patologia , Antineoplásicos/uso terapêutico , Criança , Terapia Combinada , Diarreia/etiologia , Humanos , Neoplasias Hepáticas/complicações , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/cirurgia , Imageamento por Ressonância Magnética , Masculino , Prognóstico , Sarcoma/complicações , Sarcoma/diagnóstico por imagem , Sarcoma/tratamento farmacológico , Sarcoma/cirurgia , Tomografia Computadorizada por Raios X , Redução de PesoRESUMO
Breast cancer is the most frequent cancer among women. Screening programs are able to diagnose early lesions in an infra-clinic state. Percutaneous procedures are simple to do and well tolerated by women, they provide an histological diagnosis. This way of doing may reensure rapidly, without a surgical approach, the women with benign lesions. In cases of invasive cancers, percutaneous procedures are also able to optimize the ongoing therapeutic strategy. The type of the radiological anomaly determines the technical guidage of the procedure and the type of material. Ultrasonographic guidage is used for opacities and needles of small size can be used (micro-biopsy). With microcalcifications, the guidage is made with mammographic stereotaxis, these lesions are usually complex and they need needles of big size (macrobiopsy).
Assuntos
Mama/patologia , Biópsia por Agulha/métodos , Doenças Mamárias/diagnóstico , Feminino , Humanos , Imageamento por Ressonância Magnética , Ultrassonografia MamáriaRESUMO
Current value of sonography for the characterization of focal liver lesions Incidental focal lesions are frequently discovered during sonographic exploration of the liver. Solid lesions remain often questionable, particularly in oncological or infectious patients. Doppler exploration generally doesn't help and other modalities, such as CT, MRI or even biopsy are necessary to definitively categorize the lesion. Ultrasound contrast agents associated with contrast detection ultrasound mode give the opportunity to follow the blood flow until the capillary level. Thus the dynamical behavior of blood flow in tissue is now observable with US, as it was previously with CT or MRI alone. The aim of this paper is to review the actual knowledge about the characterization of focal liver lesions with sonographic dynamic enhancement and to discuss the advantages and limitations of this particular technique.
Assuntos
Hepatopatias/diagnóstico por imagem , Meios de Contraste , Humanos , UltrassonografiaRESUMO
Approximately 1% of the fetuses present some dilatation of their urinary tract in utero. More than 50% of these antenatally detected hydronephrosis will disappear spontaneously after birth. The other 50% comprises ureteropelvic junction obstruction, vesico-ureteral reflux and primary megaureters. Postnatal radiological evaluation (renal ultrasonography and VCUG) is performed in every infant with a significantly dilated renal pelvis (> 8 mm between 20 and 30 weeks or > 10 mm after 30 weeks in utero). Renal nuclear scan should be done in every child with significant/worsening post-natal hydronephrosis. Antibioprophylaxis will be started from birth to prevent urinary tract infection. Medical or surgical approach will be chosen in the light of the uroradiological exam results and the clinical progress.
Assuntos
Hidronefrose/diagnóstico , Hidronefrose/etiologia , Diagnóstico Pré-Natal , Feminino , Humanos , Hidronefrose/terapia , Recém-Nascido , Rim/diagnóstico por imagem , Testes de Função Renal , Gravidez , Cintilografia , Ultrassonografia , UrografiaRESUMO
Mastitis is the inflammation of breast tissue. From a pathophysiological point of view, mastitis reflects a variety of underlying etiologies. It can be due to non-infectious inflammation, infection (generally of bacterial origin) but can also be caused by inflammation resulting from malignant tumor growth. Mastitis always manifests clinically by three cardinal signs of inflammation, which are redness, heat and pain. Breast specialists examining women with mastitis should proceed as follows: first, it is important to distinguish between cancer-related and non-cancer-related breast inflammation, since their clinical presentation can be misleading. Cancer-related mastitis reflecting the presence of aggressive cancer is less commonly observed than other forms of mastitis but its diagnosis, which can sometimes be difficult, needs to be made, or excluded, without delay. Once cancer-related mastitis has been excluded, the causes of inflammation should be elucidated to enable rapid treatment and patient recovery.
Assuntos
Mastite/diagnóstico , Árvores de Decisões , Diagnóstico por Imagem , Feminino , Humanos , Papel do Médico , RadiologiaRESUMO
The filamentous brain lesions that define Alzheimer disease (AD) consist of senile plaques and neurofibrillary tangles. Undulated pathological filaments--curly fibers or neuropil threads--also occur in the neuropil. Beta-amyloid precursor proteins are synthesized by many cells outside the central nervous system and recently, deposition of beta-amyloid-protein was reported to occur in non-neuronal tissues. In addition, increasing data claim the importance of chronic inflammation in the pathogenesis of AD. These observations suggest that AD may be a widespread systemic disorder. Here we report that pathological argyrophilic filaments with histochemical properties of amyloid showing striking morphological similarity to curly fibers and/or tangles accumulate not only in ependymal layer and in epithelial cells of choroid plexus, but also in several other organs (e.g. liver, pancreas, ovary, testis, thyroid) in AD. The ependyma, choroid plexus, and various organs of 39 autopsy cases were analyzed. In search of curly fiber and tangle-like changes in organs other than brain, 395 blocks from 21 different tissues of 24 AD cases, 5 cases with discrete or moderate AD-type changes, and 10 control cases were investigated. We found in non-neuronal cells "curly fibers" or "tangles" immunoreactive with antibodies to P component, Tau-protein, ubiquitin, fibronectin, and Apolipoprotein-E, but lacking immunoreactivity with antibodies to neurofilament proteins. Ultrastructurally they consist of densely packed straight and paired helical filaments and closely resemble neurofibrillary tangles and neuropil threads. These observations indicate that the formation of "curly fibers" and "tangles" is not unique to the central nervous system. The results suggest that AD might be a systemic disorder or that similar fibrillary changes to tangles and curly fibers may also be associated with other amyloidosis than beta-amyloidosis. Further investigations are necessary to understand the pathogenetic interest of these fibrillary changes outside the CNS.
Assuntos
Doença de Alzheimer/patologia , Fibras Nervosas/patologia , Emaranhados Neurofibrilares/patologia , Adulto , Idoso , Humanos , Técnicas Imunoenzimáticas , Microscopia Confocal , Microscopia Eletrônica , Pessoa de Meia-Idade , Fibras Nervosas/ultraestrutura , Especificidade de ÓrgãosRESUMO
The question of whether thread- and tangle-like inclusions of the choroid plexus (known as Biondi inclusions) are related to the cortical lesions in Alzheimer disease (AD) has been debated for almost a century, yet remains unanswered. Recently beta-amyloid protein was biochemically isolated from the plexus, indicating a possible pathogenetic relationship between the degenerative changes of the cerebral cortex and those of the plexus. The goal of the present study was to analyze whether or not a significant correlation exists between the occurrence of the cortical AD-type changes and those in the ependyma and choroid plexus. In 292 consecutive autopsy cases several cortical areas, the ependyma, and the choroid plexus were analyzed to look for AD-type changes and Biondi inclusions using histochemical staining techniques and immunohistochemistry. A semiquantitative analysis of the density of cortical AD-type changes showed that of the 292 cases, 63 had severe cortical changes, 23 moderate changes, and 142 discrete changes. In 64 cases no plaques or neurofibrillary tangles were found. The number of cases with thread- and tangle-like elements in the plexus and ependyma was more than 96% in the 3 groups with cortical AD-type lesions, but low in the group without AD-type cortical changes (19%). The pathological argyrophilic filaments accumulating in the ependymal layer and plexus had histochemical properties of amyloid and were immunoreactive with antibodies to P component, ubiquitin, fibronectin and Tau protein. They did not react with antibodies to neurofilament proteins. Ultrastructurally, they consisted of densely packed straight and paired helical filaments and closely resembled neurofibrillary tangles and neuropil threads. The highly significant correlation (chi2, p = 0.001; R = 0.85) between the occurrence of AD-type changes in the cortex and those in ependyma and plexus suggests a pathogenetic relationship.
Assuntos
Doença de Alzheimer/patologia , Plexo Corióideo/patologia , Epêndima/patologia , Corpos de Inclusão/patologia , Fibras Nervosas/patologia , Emaranhados Neurofibrilares/patologia , Doença de Alzheimer/etiologia , Histocitoquímica , Humanos , Imuno-HistoquímicaRESUMO
Our objective is to describe a new test phantom that permits the objective assessment of image quality in conventional and digital mammography for different types of breast tissue. A test phantom, designed to represent a compressed breast, was made from tissue equivalent materials. Three separate regions, with different breast tissue compositions, are used to evaluate low and high contrast resolution, spatial resolution and image noise. The phantom was imaged over a range of kV using a Contour 2000 (Bennett) mammography unit with a Kodak MinR 2190-MinR L screen-film combination and a Senograph 2000D (General Electric) digital mammography unit. Objective image quality assessments for different breast tissue compositions were performed using the phantom for conventional and digital mammography. For a similar mean glandular dose (MGD), the digital system gives a significantly higher contrast-to-noise ratio (CNR) than the screen-film system for 100% glandular tissue. In conclusion, in mammography, a range of exposure conditions is used for imaging because of the different breast tissue compositions encountered clinically. Ideally, the patient dose-image quality relationship should be optimized over the range of exposure conditions. The test phantom presented in this work permits image quality parameters to be evaluated objectively for three different types of breast tissue. Thus, it is a useful tool for optimizing the patient dose-image quality relationship.
Assuntos
Doenças Mamárias/diagnóstico por imagem , Mamografia/métodos , Imagens de Fantasmas , Intensificação de Imagem Radiográfica/métodos , Mama/patologia , Neoplasias da Mama/diagnóstico por imagem , Humanos , Controle de Qualidade , Doses de Radiação , Intensificação de Imagem Radiográfica/instrumentação , Ecrans Intensificadores para Raios XRESUMO
Dynamic computed tomography (CT) is frequently performed to assess the mediastinum in trauma patients with a suspected thoracic aortic rupture. Its usefulness lies in demonstrating a mediastinal hematoma. However, many patients still undergo conventional aortography despite a normal chest. CT, because of a perceived insensitivity of this technique for diagnosing aortic rupture. One application of helical CT is CT angiography, in which multiple thin sections are acquired through a blood vessel during the injection of iodinated contrast. Good demonstration of vascular pathology can be achieved, especially with 3-D reconstructions. This article reviews a series of four surgically proven thoracic aortic ruptures studied using helical CT, and one case proven to be false-positive by both helical CT angiography and conventional angiography. Correlation between conventional and helical CT angiography was excellent, with similar findings and the same interpretation pitfalls. Helical CT is fast and noninvasive. Combined examination of other anatomical areas can be performed in the same procedure in major trauma patients. Helical CT may potentially decrease the need for aortography in these acutely injured patients.
Assuntos
Aorta Torácica/lesões , Ruptura Aórtica/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Ferimentos não Penetrantes/diagnóstico por imagem , Adulto , Idoso , Aorta Torácica/cirurgia , Ruptura Aórtica/cirurgia , Aortografia , Humanos , Masculino , Estudos Retrospectivos , Ferimentos não Penetrantes/cirurgiaAssuntos
Vasculite por IgA/complicações , Vasculite por IgA/diagnóstico , Doenças Testiculares/etiologia , Doenças Testiculares/patologia , Pré-Escolar , Diagnóstico Diferencial , Humanos , Masculino , Dor/etiologia , Escroto/diagnóstico por imagem , Doenças Testiculares/diagnóstico por imagem , UltrassonografiaRESUMO
Our objective was to establish the age-related 3D size of maxillary, sphenoid, and frontal sinuses. A total of 179 magnetic resonance imaging (MRI) of children under 17 years (76 females, 103 males) were included and sinuses were measured in the three axes. Maxillary sinuses measured at birth (mean+/-standard deviation) 7.3+/-2.7 mm length (or antero-posterior)/4.0+/-0.9 mm height (or cranio-caudal)/2.7+/-0.8 mm width (or transverse). At 16 years old, maxillary sinus measured 38.8+/-3.5 mm/36.3+/-6.2 mm/27.5+/-4.2 mm. Sphenoid sinus pneumatization starts in the third year of life after conversion from red to fatty marrow with mean values of 5.8+/-1.4 mm/8.0+/-2.3 mm/5.8+/-1.0 mm. Pneumatization progresses gradually to reach at 16 years 23.0+/-4.5 mm/22.6+/-5.8 mm/12.8+/-3.1 mm. Frontal sinuses present a wide variation in size and most of the time are not valuable with routine head MRI techniques. They are not aerated before the age of 6 years. Frontal sinuses dimensions at 16 years were 12.8+/-5.0 mm/21.9+/-8.4 mm/24.5+/-13.3 mm. A sinus volume index (SVI) of maxillary and sphenoid sinus was computed using a simplified ellipsoid volume formula, and a table with SVI according to age with percentile variations is proposed for easy clinical application. Percentile curves of maxillary and sphenoid sinuses are presented to provide a basis for objective determination of sinus size and volume during development. These data are applicable to other techniques such as conventional X-ray and CT scan.
Assuntos
Seio Frontal/anatomia & histologia , Imageamento por Ressonância Magnética , Seio Maxilar/anatomia & histologia , Seio Esfenoidal/anatomia & histologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Recém-Nascido , MasculinoRESUMO
The aim was to propose a strategy for finding reasonable compromises between image noise and dose as a function of patient weight. Weighted CT dose index (CTDI(w)) was measured on a multidetector-row CT unit using CTDI test objects of 16, 24 and 32 cm in diameter at 80, 100, 120 and 140 kV. These test objects were then scanned in helical mode using a wide range of tube currents and voltages with a reconstructed slice thickness of 5 mm. For each set of acquisition parameter image noise was measured and the Rose model observer was used to test two strategies for proposing a reasonable compromise between dose and low-contrast detection performance: (1) the use of a unique noise level for all test object diameters, and (2) the use of a unique dose efficacy level defined as the noise reduction per unit dose. Published data were used to define four weight classes and an acquisition protocol was proposed for each class. The protocols have been applied in clinical routine for more than one year. CTDI(vol) values of 6.7, 9.4, 15.9 and 24.5 mGy were proposed for the following weight classes: 2.5-5, 5-15, 15-30 and 30-50 kg with image noise levels in the range of 10-15 HU. The proposed method allows patient dose and image noise to be controlled in such a way that dose reduction does not impair the detection of low-contrast lesions. The proposed values correspond to high- quality images and can be reduced if only high-contrast organs are assessed.
Assuntos
Artefatos , Modelos Teóricos , Radiografia Abdominal/métodos , Tomografia Computadorizada por Raios X/métodos , Adolescente , Peso Corporal/fisiologia , Criança , Pré-Escolar , Protocolos Clínicos/normas , Humanos , Processamento de Imagem Assistida por Computador/métodos , Lactente , Recém-Nascido , Doses de Radiação , Intensificação de Imagem Radiográfica/métodos , Radiografia Abdominal/normas , Radiometria/métodos , Sensibilidade e Especificidade , Processamento de Sinais Assistido por Computador , Tecnologia Radiológica , Tomografia Computadorizada por Raios X/normasRESUMO
Although the presence of valves in the distal portion of the internal jugular veins has been widely described by anatomists and pathologists, their existence remains underscored in the medical literature. We set out to demonstrate their sonographic aspect and to evaluate their morphology, location and prevalence. Seventy-five cadavers were evaluated for the presence and aspect of such valves through neck dissections. Concurrent evaluation of the sonographic character of these structures was performed in another cohort of 75 adults. Valves of the distal portion of the internal jugular veins were found in 93 % of the cadaveric studies. Ultrasonography easily demonstrated the valve leaflets in 87 % of patients; all were observed in the distal portion of the internal jugular (IJ) veins. Sixty percent were bilateral with the majority of unilateral veins found on the right side. High-resolution ultrasonography easily demonstrates valves in the distal portion of the IJ veins which are present in the great majority of persons. Their evaluation may be of use in percutaneous procedures using this venous access.
Assuntos
Veias Jugulares/diagnóstico por imagem , Idoso , Cadáver , Feminino , Humanos , Veias Jugulares/anatomia & histologia , Masculino , Pessoa de Meia-Idade , UltrassonografiaRESUMO
El presente trabajo realiza una descripción detallada del procedimiento quirúrgico para colocar implantes dentales en los huesos maxilares. Se inicia este estudio con la selección del paciente candidato a recibir un implante, realizando una evaluación de su salud general, de sus condiciones orales y de las posibilidades anatómicas de la zona ósea del maxilar donde se planifica colocar los implantes. A continuación se describe el plan de tratamiento con sus etapas de eliminación de patología oral prevalente, selección de los implantes e información al paciente, para enseguida hacer un análisis del procedimiento quirúrgico propiamente tal. En esta fase se describe en detalle los pasos quirúrgicos de las etapas de colocación del implante y de conexión del emergente transmucoso, para finalmente considerar las complicaciones postoperatorias inmediatas y posteriores a la colocación de los implantes oseointegrados