Features and Prospects of Dual-energy Computed Tomography for Evaluation of Lung Cancer / 中国医学科学院学报

Dual-energy computed tomography,with fast image acquisition at two different X-ray energies,enables material-specific and spectral imaging,which offers objective and quantitative parameters for tumor detection,characterization,staging,and treatment monitoring without increasing radiation exposure.This article reviews the applications of dual-energy computed tomography technique and its applications in the evaluation of lung cancer and elucidates its future developments.

Associação de força de preensão palmar e osteoporose avaliada por densitometria óssea (DXA) em idosos quilombolas: um estudo seccional / Association between handgrip strength and osteoporosis assessed by bone densitometry in elderly quilombolas: a sectional study

Objetivo: Verificar a associação de força de preensão palmar e osteoporose em idosos quilombolas. Método: Trata-se de um estudo seccional com 70 participantes (idade 65,58 ± 6.67 anos) de ambos os sexos. A densidade mineral óssea (DMO), massa muscular (MM) e o percentual de gordura foram analisados pela absortometria de raios-x de dupla energia (DXA) e a força de preensão palmar (FPP) por meio do dinamômetro de mão. O ponto de coorte adotado para identificação de osteoporose foi o da Organização Mundial de Saúde (OMS). A identificação do status da sarcopenia foi realizado para caraterização da amostra e para o diagnóstico foi utilizado os critérios propostos pelo European Working Group on Sarcopenia in Older People (EWGSOP). A FPP foi associada positivamente e significativamente com a DMO. Resultados: A osteopenia foi identificada em 42,8% da amostra e a osteoporose em 20%, sem diferença entre as frequências segundo o sexo (p = 0,161). Conclusão: Nos idosos quilombolas a baixa FPP esteve positivamente associada com baixa DMO. Portanto, sugerindo que a FPP pode ser considerada um fator de risco importante de estado ósseo em idosos quilombolas.

Objective: The aim of this study was to verify the association between handgrip strength and osteoporosis in elderly quilombolas. Method: It is a sectional study with 70 participants (aged 65.58 ± 6.67 years) of both sexes. Bone mineral density (BMD), muscle mass and fat percentage were analysed by dual-energy X-ray absorptiometry (DXA) and handgrip strength by a hand dynamometer. Subjects were classified as having osteoporosis according to World Health Organization (WHO) cutoff point. The identification of sarcopenia was performed to characterize the sample and the diagnosis was done according to the European Working Group on Sarcopenia in Older People (EWGSOP) criteria. Results: Osteopenia was identified in 42.8% of the sample and osteoporosis in 20%, with no difference between sex (p = 0.161). HGS was positively associated with BMD. Osteopenia was identified in 42.8% of the sample and osteoporosis in 20%, with no difference between the frequencies according to sex (p = 0.161). Conclusion: In the elderly quilombolas low HGS was positively associated with low BMD. Therefore, suggesting that HGS may be considered an important risk factor for bone state in this population.

Effect of a noise-optimized virtual monoenergetic reconstruction technique on dual-energy CT for image quality of inflammatory bowel disease / 中南大学学报(医学版)

To assess the value of noise-optimized virtual monoenergetic imaging (VMI+) reconstruction technique on objective and subjective image quality in patients with inflammatory bowel disease (IBD) undergoing abdominal dual-energy computed tomography (DECT).
 Methods: Datasets from 32 patients (22 men, 10 women) with IBD, who underwent abdominal DECT, were reconstructed by using the standard linearly blended (M_0.6), traditional monoenergetic (VMI) and VMI+ algorithms in 10-keV intervals from 40-100 keV. Attenuation in IBD lesions was measured to perform objective evaluation using signal-to-noise (SNR) and contrast-to-noise ratios (CNR). Subjective evaluation was performed by 3 independent blinded radiologists using 5-point Likert scales. The overall image quality, image sharpness, lesion delineation, and image noise were analyzed. 
 Results: Mean SNR and CNR peaked at 40 keV VMI+ series (SNR 8.28±2.34, CNR 5.10±2.10) and they were significantly higher than those in linearly blended (SNR 5.82±1.44, CNR 1.53±0.86) and all VMI series (all P<0.01). Subjective image parameter was the highest for the 50 keV VMI+ series regarding overall image quality (mean 4.80, all P<0.01). The highest image sharpness scores were observed at 40 and 50 keV VMI+ reconstructions (mean 4.14 and 4.25, respectively; P=0.415). VMI+ series at 40 keV provided the highest lesion delineation (mean 4.52, all P<0.01). Image noise was low at the 100 keV VMI+ and VMI series (mean 4.58 and 4.40, respectively; P≥0.11).
 Conclusion: Low-keV VMI+ reconstructions improves SNR, CNR, and subjective image quality significantly in patients with IBD.

Relevant aspects of imaging in the diagnosis and management of gout / Aspectos relevantes do diagnóstico e seguimento por imagem na gota

ABSTRACT Gout is an inflammatory arthritis characterized by the deposition of monosodium urate crystals in the synovial membrane, articular cartilage and periarticular tissues leading to inflammation. Men are more commonly affected, mainly after the 5th decade of life. Its incidence has been growing with the population aging.In the majority of the cases, the diagnosis is made by clinical criteria and synovial fluid analysis, in search for monosodium urate crystals. Nonetheless, gout may sometimes have atypical presentations, complicating the diagnosis. In these situations, imaging methods have a fundamental role, aiding in the diagnostic confirmation or excluding other possible differential diagnosis. Conventional radiographs are still the most commonly used method in gout patients’ evaluation; nevertheless, this is not a sensitive method, since it detect only late alterations. In the last years, there have been several advances in imaging methods for gout patients. Ultrasound has shown a great accuracy in the diagnosis of gout, identifying monosodium urate deposits in the synovial membrane and articular cartilage, in detecting and characterizing tophi and in identifying tophaceous tendinopathy and enthesopathy. Ultrasound has also been able to show crystal deposition in patients with articular pain in the absence of a classical gout crisis. Computed tomography is an excellent method for detecting bone erosions, being useful in spine involvement. Dual-energy CT is a new method able to provide information about the chemical composition of tissues, with high accuracy in the identification of monosodium urate deposits, even in the early stages of the disease and in cases of difficult characterization. Magnetic resonance imaging is useful in the evaluation of deep tissues not accessible by ultrasound. Besides the diagnosis, with the emergence of new drugs that aim to reduce tophaceous burden, imaging methods have become useful tools in monitoring the treatment of patients with gout.

RESUMO A gota é uma artrite caracterizada pela deposição de cristais de monourato sódico na membrana sinovial, na cartilagem articular e nos tecidos periarticulares que leva a um processo inflamatório. Na maioria dos casos o diagnóstico é estabelecido por critérios clínicos e pela análise do líquido sinovial, em busca dos cristais de MSU. Porém, a gota pode se manifestar de maneiras atípicas e dificultar o diagnóstico. Nessas situações, os exames de imagem têm papel fundamental, auxiliam na confirmação diagnóstica ou ainda excluem outros diagnósticos diferenciais. A radiografia convencional ainda é o método mais usado no acompanhamento desses pacientes, porém é um exame pouco sensível, por detectar somente alterações tardias. Nos últimos anos, surgiram avanços nos métodos de imagem em relação à gota. O ultrassom se mostra um exame de grande acurácia no diagnóstico de gota, identifica depósitos de MSU na cartilagem articular e nos tecidos periarticulares e detecta e caracteriza tofos, tendinopatias e entesopatias por tofos. A tomografia computadorizada é um ótimo exame para a detecção de erosões ósseas e avaliação do acometimento na coluna. A tomografia computadorizada de dupla-energia, um método novo, fornece informações sobre a composição química dos tecidos, permite a identificação dos depósitos de MSU com elevada acurácia. A ressonância magnética pode ser útil na avalição dos tecidos profundos, não acessíveis ao ultrassom. Além do diagnóstico, com o surgimento de drogas que visam reduzir a carga tofácea, os exames de imagem se tornam uma ferramenta útil no acompanhamento do tratamento dos pacientes com gota.

Can a dual-energy computed tomography predict unsuitable stone components for extracorporeal shock wave lithotripsy?

PURPOSE: To assess the potential of dual-energy computed tomography (DECT) to identify urinary stone components, particularly uric acid and calcium oxalate monohydrate, which are unsuitable for extracorporeal shock wave lithotripsy (ESWL). MATERIALS AND METHODS: This clinical study included 246 patients who underwent removal of urinary stones and an analysis of stone components between November 2009 and August 2013. All patients received preoperative DECT using two energy values (80 kVp and 140 kVp). Hounsfield units (HU) were measured and matched to the stone component. RESULTS: Significant differences in HU values were observed between uric acid and nonuric acid stones at the 80 and 140 kVp energy values (p or =90%, calcium oxalate dihydrate group: monohydrate<90%). Significant differences in HU values were detected between the two groups at both energy values (p<0.001). CONCLUSIONS: DECT improved the characterization of urinary stone components and was a useful method for identifying uric acid and calcium oxalate monohydrate stones, which are unsuitable for ESWL.

Comparación de la reproducibilidad en las mediciones angulares entre trazado manual y computarizado / A comparison of angle measure reproducibility between manual and computerized tracing

INTRODUCCIÓN: las cefalometrías digitales permiten controlar los errores que se generan en el trazo manual, por eso el propósito de este estudio fue evaluar la reproducibilidad y precisión de las medidas angulares entre un trazo manual y el obtenido con el programa Cephapoint en una radiografía digital. MÉTODOS: se utilizaron 11 radiografías digitales directas tomadas a estudiantes de ortodoncia, las cuales se introdujeron en el programa Cephapoint. Se hizo la medición de 9 ángulos, cada uno medido en la radiográfia digital de manera manual y en el programa Cephapoint. Todas las medidas fueron hechas por 3 operadores con intervalo de 1 semana. Se halló el promedio de error interobservador para medir la reproducibilidad de cada medida angular, y el promedio de error intraobservador para determinar la precisión de cada observador. RESULTADOS: : el ángulo FH/N/Pg tuvo la menor diferencia en el error interobservador (0,10°) en ambos métodos, favoreciendo el trazado manual. Mientras que los ángulos con menor diferencia de error interobservador en el trazado computarizado fueron: II-NB (0,11°) y N-A/Pg (0,11°). La reproducibilidad intraobservador mostró un Coeficiente de Correlación Intraclase (CCI), excelente para ambos métodos. CONCLUSIONES: la reproducibilidad de las medidas angulares con el trazado manual y computarizado no presentó diferencias significativas. De acuerdo a los hallazgos de este estudio, los métodos evaluados brindan igual validez diagnóstica.

INTRODUCTION: digital cephalometry allows handling errors produced during manual tracing; the purpose of this study was therefore to evaluate the reproducibility and precision of angle measures between manual tracing and that obtained with Cephapoint in digital radiography. METHODS: 11 direct digital radiographs taken to orthodontics students were introduced in the Cephapoint computer program. 9 angles were measured in both hand-tracing digital radiography and Cephapoint. All measurements were made by 3 operators with 1-week interval. We calculated the average interobserver error to find the reproducibility of each angle measure, and the average intra-observer error to determine the accuracy of each observer. RESULTS: : the FH/N/Pg angle showed the smallest interobserver error difference (0.10°) in both methods, favoring manual tracing. On the other hand, the angles with the smallest inter-observer error difference in computerized tracing were LI-NB (0.11°) and N-A/Pg (0.11°). Intraobserver reproducibility showed excellent Intraclass Correlation Coefficient (ICC) in both methods. CONCLUSIONS: reproducibility of angular measurements did not show significant differences between manual and computerized tracing. According to the findings of this study, the methods under evaluation offer equal diagnostic validity.

Uso de la densitometria a doble fotón (DXA) en Ortopedia / The two-photon densitometry (DXA) in Orthopedy Abstract

La densitometría a doble fotón (DXA) es un método de utilidad para determinar la densidad mineral ósea (DMO) de columna y cadera y de manera especial el tejido esponjoso, y tiene un papel determinante para evaluar el paciente en riesgo de tener una osteoporosis y así escoger la terapia más adecuada para tratar este problema. Con el transcurrir de los años se ha intentado utilizar este procedimiento para estudiar otras posibilidades como la osteointegracion de las artroplastias o las características del tejido cortical. El objetivo de esta revisión es poner, en el tapete de discusión, la utilidad de este método en el estudio de las patologías ortopédicas, de manera especial en la consolidación y la osteointegracion de los implantes y que de alguna manera forme parte de las ayudas paraclínicas del cirujano ortopedista(AU)

The two-photon densitometry (DXA) is a useful method to determine the bone mineral density(BMD) of spine and hip, especially the trabecular tissue, and has a key role to assess the patient at risk for osteoporosis and thus choose the most appropriate therapy for this problem. With the passing of the years have tried to use this method to study other possibilities as osseointegration of arthroplasties or characteristics of the cortical tissue. The aim of this review is to put on the table for discussion, the usefulness of this method in the study of orthopedic pathologies, especially in the consolidation and osseointegration of implants and somehow part of the paraclinical aid the orthopedic surgeon(AU)

Reproducibilidad en la ubicación de puntos cefalométricos de tejidos blandos en radiografías convencionales y digitales directas / Reproducibility of soft tissue cephalometric landmark identification by conventional and digital direct radiography

Introducción: es escasa la información sobre la reproducibilidad de puntos cefalométricos de tejidos blandos, el propósito de este estudio fue evaluar la reproducibilidad y precisión de la ubicación de los puntos cefalométricos de tejidos blandos en una radiografía digital directa y una radiografía convencional. Método: se utilizaron 11 pares de radiografías convencionales y radiografías digitales directas las cuales se introdujeron en el programa Cephapoint. Se ubicaron 10 puntos cefalométricos en un plano cartesiano (X y Y) en las imágenes convencional y digital. Las medidas fueron hechas dos veces por 3 operadores con intervalo de 1 semana. Se halló el promedio de error interobservador para medir la reproducibilidad de cada punto y el error intraobservador para determinar la precisión. Resultados: el error interobservador en la ubicación de puntos cefalométricos en tejidos blandos fue menor a 1 mm para la mayoría de los puntos en ambas imágenes, excepto para mentón y pogonion, sin diferencias estadísticamente significativas. Se encontraron diferencias estadísticamente significativas entre las varianzas en el eje X, con menor variabilidad para la radiografía digital en los puntos labrale superior (p = 0,043), subnasal (p = 0, 013), columnella (p = 0,038), stomion superior (p = 0,029) y stomion inferior (p = 0,015). En el eje y no se presentaron diferencias estadísticamente significativas entre los dos métodos. La evaluación de la reproducibilidad intraobservador mostró coeficiente de correlación intraclase (CCI) excelente (0,935) en ambos métodos. Conclusión: de acuerdo con los hallazgos de este estudio las radiografías y los métodos evaluados brindan igual validez diagnóstica.

Introduction: there is little information on the reproducibility of soft tissue cephalometric points; the purpose of this study was then to evaluate the reproducibility and accuracy of soft tissue cephalometric landmark identification in direct digital radiography and conventional radiography. Methods: 11 pairs of conventional and direct digital radiographs were introduced in the Cephapoint program. 10 cephalometric points were located on a Cartesian plane (X and Y) in conventional and digital images. The measurements were taken twice by 3 operators with 1 week interval. Interobserver average error was calculated in order to assess reproducibility in each point, and intraobserver error was used to determine accuracy. Results: interobserver error in soft tissue cephalometric points was less than 1 mm for most points in both images, except in chin and pogonion, with no statistically significant differences. Statistically significant differences were found between the variances in the X axis, with less variability in the case of digital radiography in these points: labrale superius (p = 0.043), subnasale (p = 0, 013), columella (p = 0.038), stomion superius (p = 0.029), and stomion inferius (p = 0.015). The Y axis did not show statistically significant differences between the two methods. The assessment of intraobserver reproducibility showed an excellent Intraclass Correlation Coefficient (ICC) (0.935) in both methods. Conclusion: according to the findings of this study, the evaluated radiographs and methods offer similar diagnostic accuracy.

Value of dual-source CT in diagnosis of single ventricle / 生物医学工程学杂志

This paper was aimed to explore the features of single ventricle with dual source computed tomography (DSCT) and the value of the modality in diagnosis of the single ventricle disease. Dual-source computed tomography imaging of 14 cases of single ventricle compared with the results of surgery and cardiac catheter were retrospectively analyzed. Firstly, 14 cases were classified into three types according to Anderson classification method, including 7 cases(50. 0%) left ventricular type, 3 cases(21. 4%) right ventricular type and 4 cases (28. 6%) undecided ventricular type. Secondly, in accompanying malformation respect, pulmonary stenosis, bilateral superior vena cava, atrial septal defect (ASD) and common atrioventricular valve were presented frequently. Thirdly, affiliated cardiac chamber of left ventricular type were mostly in front of the major cardiac chamber (5 cases,71. 4%), while affiliated cardiac chamber of right ventricular type were behind of the major cardiac chamber totally. Fourthly, more than half of aortas and pulmonary arteries stemming from common cardiac chamber can be seen (8 cases, 57. 1%). Meanwhile the aorta valves were more on the right of pulmonary valve (9 cases, 64. 3%). The classification of 10 cases of single ventricle was compared with the results of surgery, and the coincidence rate is 100%. DSCT can diagnose the single ventricle disease accurately. The aorta, pulmonary artery and coronary artery can be displayed completely and simultaneously as well.

Dual-energy computed tomography angiography for evaluating the renal vascular variants / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recognizing renal vascular variants preoperatively is important in order to avoid vascular complications during surgery. This study aimed to investigate the renal vascular variants with dual-energy computed tomography (DECT) angiography to provide valuable information for surgery.</p><p><b>METHODS</b>A total of 378 patients underwent DECT. The number, size, course and relationships of the renal vessels were retrospectively observed from the scans. Anomalies of renal arteries and veins were recorded and classified. Multiplanar reformations (MPR), maximum intensity projections (MIP), and volume renderings (VR) were used for analysis.</p><p><b>RESULTS</b>In 378 patients (756 kidneys), renal artery variations were discovered and recorded in 123 kidneys (16.3%, 123/756) of 106 patients (28.0%, 106/378). Type IB (early branches of the only one main renal artery) and IC (accessory renal artery with only one main renal artery) were found most frequently with an incidence of 11.4% (43/378) and 14.5% (55/378). The incidence of renal artery variations in the left kidney was not statistically different than in the right kidney (12.4% vs. 11.1%). The incidence of renal vein variations was detected in 104 patients (27.5%, 104/378). The incidence of venous variants in the right kidney was higher than in the left kidney (20.1% vs. 7.4%), but left renal vein variations were more complex. Variants of the left renal vein were detected in 28 patients including type 1 (circumaortic left renal vein) in eight cases, type 2 (retroaortic left renal vein) in seven cases, type 3 (abnormal reflux) in six cases, type 4 (late venous confluence of left renal vein) in five cases, and type 5 (rare type) in two cases. The frequency of left renal vein variation associated with the left renal accessory artery was significantly higher than with early branches of the left renal artery (P = 0.037).</p><p><b>CONCLUSIONS</b>The renal vascular variants are rather common and complex. DECT angiography can demonstrate the precise anatomy of the renal vessels, which is a benefit for renal transplantation or other renal operations.</p>

Estado actual del manejo médico de la fracturas del fémur proximal por osteoporosis: revisión de la bibliografía / Current status of medical management of proximal femur fracture due to osteoporosis: a review of the literature

Las fracturas del fémur proximal, secundarias a caída de su altura, pacientes posmenopáusicas con osteoporosis, es un acontecimiento de fecuencia relativa. El médico tratante debe estar preparado para los eventos tanto pre como postoperatorio que suelen ocurrir. Se propone la creación de un Grupo de Atención Geriátrica (GAG) que enfoque los problemas médicos de este grupo de pacientes y sobre todo que tenga conocimiento de la osteoporosis, su dignóstico y tratamiento médico, para prevenir una nueva fracturas. Una vez que egresa del hospital se debe indicar una densitometría doble foton (DXA) e iniciar el tratamiento para la osteoporosis dos semanas luego del egreso y hasta el momento el ácido zoledronico es el único que ha demostrado que disminuye el riesgo de mortalidad y nueva fracturas.

A fracture of the proximal femur secondary to drop height in postmenopausal women with osteoporosis is a relative frequency of occurrence. The treating physician must be prepared for both pre-and postoperative events that do occur. It proposes the establishment of a Gerietric Care Group (GAG) that approach the medical problems of this group of patients and especially with knowledge of osteoporosis, its diagnosis and medical treatment to prevent a new fracture. Once discharged from the hospital should indicate two-photon densitometry (DXA) and initiate treatment for osteoporosis two weeks after graduation and until zoledronic acid is the only one that has been shown to decrease the risk of mortality and new fracture.

Clinical application of dual-source computed tomographic urography using dual-energy virtual non enhanced computed tomography / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the clinical feasibility of dual-source computed tomographic urography using dual-energy virtual non-enhanced CT.</p><p><b>METHODS</b>Totally 240 patients received dual-source CT, which included true non-enhanced CT (TNCT) , nephrographic phase scanning with dual-energy mode (100kVp/230mAs and Sn140kVp/178mAs) , and excretory phase scanning. A contrast bolus injection of 100 ml (370 mgI/ml) contrast agent was applied (4.5ml/s) , followed by 100ml normal saline (4.5ml/s) . Virtual non-enhanced CT (VNCT) image sets were reformatted from 'Liver VNC ' software. The mean CT number, noise, signal to noise ratio (SNR) , image quality, and radiation dose were compared between TNCT and VNCT image sets.</p><p><b>RESULTS</b>There was no significant difference in mean CT numbers of all organs (P>0.05) . However, VNCT images had significantly lower noise and higher SNR than TNCT images (both P<0.05) . Image quality of VNCT was lower than that of TNCT without significant difference (P>0.05) . Radiation dose of nephrographic phase with dual-energy mode was significantly higher than that of TNCT and excretory phase scanning (P<0.05) .</p><p><b>CONCLUSION</b>Dual-energy VNCT requires less radiation dose and therefore has a potential to replace TNCT in the dual-source CT urography.</p>

Detectability of rib bone lesions using dual-energy subtraction radiography / 中南大学学报(医学版)

OBJECTIVE@#To assess the value of dual-energy subtraction radiography (DESR) in the detection of rib bone lesions.@*METHODS@#The images of DESR and digital radiography (DR) in 66 patients with 118 rib bone lesions were reviewed. The detectability of DESR and DR in the rib bone lesions was analyzed by receiver operating characteristic (ROC) method, and their detection rates were compared in different thoracic regions such as those overlaid with the diaphragm and the mediastinum, located in the region of midaxillary line,and the rest.@*RESULTS@#In the detection of rib bone lesions, the area under ROC curve in the DESR group (Az=0.946) was significantly larger than that in the DR group (Az=0.755). In different regions of the rib lesions, the detection rates of DESR were significantly larger than those of DR (P<0.05).@*CONCLUSION@#DESR can improve the detection of rib bone lesions, and is a useful supplement to DR.

novel dual energy CT-based attenuation correction method in PET/CT systems: a phantom study

In present PET/CT scanners, PET attenuation correction is performed by relying on the information given by CT scan. In the CT-based attenuation correction methods, dual-energy technique [DECT] is the most accurate approach, which has been limited due to the increasing patient dose. In this feasibility study, we have introduced a new method that can implement dual-energy technique with only a single energy CT scan. The implementation was done by CT scans of RANDO phantom at tube voltages of 80 kV[P] and 140 kV[P]. The acquired data was used to obtain conversion curves [which scale CT numbers at different kV[P] to each other], in three regions including lung tissue [HU<-100], soft tissue [-100200] for the combination of 80 kV[P] /140 kV[P]. Therefore, with having the CT image in one energy, we generate the CT image at the second energy [from now we call it virtual dual-energy technique] using these kV[P] conversion curves. The attenuation map at 511 ke[V] was generated using bilinear [the most commonly used method in commercially available PET/CT scanners], real dual-energy and virtual dual-energy technique in a polyethylene phantom. In the phantom study, the created attenuation map using mentioned methods are compared to the theoretical values calculated using XCOM cross section library. The results in the phantom data show 10.1%, 4.2% and 4.3% errors for bilinear, dual-energy and virtual dual-energy techniques respectively. Further evaluation using a larger patient data is underway to evaluate the potential of the technique in a clinical setting

Dual Energy CT and its use in neuroangiography

The dual energy CT (DECT) technology has been recently employed in the form of two X-ray sources of different energies to enhance the contrast between adjacent structures. Its use in the cardiac arena has been widely highlighted due to the higher temporal resolution. However, it may also be used in the craniocervical and peripheral vasculature for better differentiation between contrast-enhanced vascular lumina and calcified plaques, in the characterisation of ureteric stones, and in the evaluation of hepatic lesions. The objective of this paper is to revisit DECT physics, review the literature and discuss its use in CT neuroangiography with case illustrations from our institution, and impact on dose savings.

Determinação da densidade mineral óssea da extremidade distal do rádio-ulna em gatos: correlação entre peso, sexo e idade / Determination the bone mineral density of the distal extremity of the radius-ulna in cats: correlation between weight, sex and age

Os valores de normalidade da densidade mineral óssea (DMO) da extremidade distal de rádio-ulna em 120 gatos clinicamente saudáveis foram determinados usando-se a técnica de densitometria óptica em imagens radiográficas. Para a padronização da técnica e interpretação da DMO, foi utilizado um programa computacional especialmente desenvolvido para a medida de densidade óptica em imagens radiográficas, que contém a imagem radiográfica da extremidade distal de rádio-ulna, e uma escala de alumínio (penetrômetro), usada como referencial densitométrico, permitindo a medida da densidade mineral óssea do rádio-ulna correspondente ao valor em milímetros da escala. Os valores médios da densidade mineral óssea da extremidade distal do rádio-ulna foram de 1,98 ± 0,52mmAl para os machos e de 1,76 ± 0,41mmAl para as fêmeas. Foram observadas correlações estatisticamente significativas entre a DMO, o peso e a idade dos animais estudados (P<0,0005).

The normal values of bone mineral density (BMD) at the distal end of the radius-ulna were established in 120 clinically healthy cats, using the technique of optical densitometry in radiographic images. The interpretation of BMD was performed using a computer software especially developed for measuring the optical density of the radiographic films, containing radiographic image of the distal extremity of the radius-ulna, and steps of an aluminum scale (penetrometer), used as a densitometric reference. This allowed the measurement of the BMD corresponding to the value in millimeters of the scale. The BMD mean values of the distal end of radius-ulna were: 1.98 ± 0.52mmAl for male and 1.76 ± 0.41 for female cats. Significant correlations were observed between BMD and weight and BMD and age (P<0.0005).

A Comparison between Dual-Exposure Dual-Energy Radiography and Standard Chest Radiography for the Diagnosis of Small Pulmonary Nodules

PURPOSE: To evaluate the utility of dual-exposure dual-energy radiography against the standard chest radiography in the discrimination of lung nodules and the presence of nodule calcification. MATERIALS AND METHODS: Twenty-nine patients with a total of 43 peripheral lung nodules were examined by dual-exposure dual-energy radiography (DER) and confirmed by a chest CT were included in the study. Of the identified peripheral lung nodules, 24 showed calcification and 19 did not. Further, 28 lesion-free regions from the same patient population were selected as negative controls. Two radiologists evaluated 71 marked locations using both standard chest radiographs (SR) and DER to determine whether the marked locations represented a true nodule, and whether nodule calcification was present. A continuous rating scale of 0-10 was used to represent each observer's confidence level. We calculated the areas under ROC curves (AUC) for SR alone and for DER, and performed a statistical analysis to compare the results. RESULTS: The ability to discriminate nodules was higher for DER than for SR. However, the was not statistically significant (p = 0.202). Inter-observer agreement was moderate regardless of if DER was used. The predictability of nodule calcification was significantly higher for DER compared to SR (p < .001). Moreover, inter-observer agreement was slight with SR alone but moderate with DER. CONCLUSION: DER, in conjunction with SR, has no additional benefit in small lung nodule discrimination but does provide a significant benefit in the characterization of nodule calcification.

Análise radiográfica da repleção de canais secundários submetidos a duas técnicas de obturação / Radiographic analysis of the repletion of secondary channels submitted to two filling techniques

O presente trabalho teve como objetivo avaliar radiograficamente o grau de preenchimento de canais secundários e laterais, confeccionados artificialmente e obturados pela técnica de condensação lateral ou técnica híbrida de Tagger. Foram utilizados 40 dentes humanos monorradiculares, limpos, autoclavados e armazenados em formol. Os espécimes foram abordados com pontas diamantadas, explorados e instrumentados pela técnica coroa-ápice, utilizando brocas Gates-Gliden (Dentsply-Maillefer) e limas tipo K-File (Kerr), sob irrigação com 2mL de hipoclorito de sódio a 1% (Iodontec) e irrigação final com 1mL de EDTA a 17% (Odontopharma) por três minutos. Em cada dente confeccionaram-se, com o auxílio de uma broca LN (Dentsply-Maillefer) e de limas endodônticas tipo K n.º 15 (Kerr), três canais laterais que se comunicavam com o canal radicular nas faces proximais das raízes dos dentes, sendo dois na mesial, nos terços cervical e apical, e um na face distal, no terço médio. Os espécimes foram divididos em dois grupos de acordo com a técnica obturadora empregada: G1 - condensação lateral e G2 - híbrida de Tagger. Foram atribuídos escores de 0 a 3 para a aparência de cada canal lateral confeccionado. Após obturação, os espécimes foram radiografados em posição ortorradial, e os dados individuais, informatizados. Teste não-paramétrico de Mann-Whitney, empregado para comparar os escores relativos ao preenchimento do material obturador no interior dos canais laterais simulados, mostrou que nos grupos 1 e 2 nos canais cervical e médio houve diferença significativa (p<0,05), com melhor desempenho para a técnica híbrida de Tagger. No terço apical não houve diferenças significativas (p>0,05) entre as técnicas obturadoras.

Comparação da densidade óptica de resinas compstas de alta viscosidade por meio do sistema digital DenoOptix / Comparison of the optical density of high-viscosity composite resins by DenOptix digital system

O objetivo deste estudo foi mensurar a densidade óptica de quatro resinas compostas de alta viscosidade (Fill Magic, P60, Solitaire e Surefil) nas espessuras de 1, 2, 3 e 4mm, utilizando o sistema digital DenOptix, e compará-las entre si. Foram utilizadas cinco placas de acrílico para cada uma das espessuras, cada uma contendo amostras de todas as resinas. Cada placa acrílica foi radiografada três vezes, sob técnica padronizada, usando uma placa óptica sob cada placa acrílica, totalizando sessenta exposição, as placas no sistema digital DenOptix, e fizeram-se três leituras ópticas consecutivas de cada imagem, totalizando 720 leituras. Os resultados, submetidos à análise estatística, permitiram concluir que os valores de densidade óptica aumentaram com o aumento das espessuras das amostras. Quando comparadas entre si, na espessura de 1mm, as resinas surefil e P60 não diferiram estatísticamnete entre si e apresentaram as maiores médias de densidade óptica, seguidas da resina Fill Magic e, por último, da resina Solitaire. Todas as resinas apresentaram diferenças estatisticas na espessura de 2 mm, sendo a Surefil a de maior expressão de densidade óptica, seguida, em ordem decrescente de densidade óptica, pelas resinas P60, Fill Magic e Solitaire. Nas espessuras de 3 mm e 4 mm, a resina Surefil apresentou a maior média de densidade óptica, seguida por P60 e Fill Magic, que não diferiram estatisticamente entre si e, por último, de Solitaire, que apresentou o menor valor médio de densidade óptica

Enhancement of MD-55-2 radiochromic film sensitivity using a multilayer film technique for applications in the low dose range

MD-55-2 is one of the Radiochromic film models with the sensitivity suitable for dose measurements ranging from 5 to 100 Gy. However, this lower limit makes the film impractical for its applications in many areas such as brachytherapy source dosimetry. n this project, the useful range of the film has been extended by using a multilayer film technique. In this technique, single-, double-, and triple- layers of films were exposed to the doses ranging from 0.5 to 10 Gy using a Co-60 photon beam. Calibration curves for corresponding layers of films were obtained with a spectrophotometer using a 680nm wavelength. The results indicated that the sensitivities of double and triple layers were approximately 200% and 300%, respectively, higher than a single-layer film. The impact of multilayer film arrangement on the energy dependence of the MD-55-2 Radiochromic film has also been examined using 100KVp, 80 KVp, and 6 MV X-ray beams. The results indicated an insignificant [within 5%] change in film responses with the beam energy. Therefore, the multilayer technique enhances the Radiochromic film sensitivity and expands its application to the low dose range in field of brachytherapy source dosimetry