[Progress of Lung Cancer Screening with Low Dose Helical Computed Tomography].

Lung cancer which represents characteristics of a heavy disease burden, a large proportion of advanced lung cancer and a low five-year survival rate is a threat to human health. It is essential to implement population-based lung cancer screening to improve early detection and early treatment. The National Lung Screening Trial (NLST) demonstrated that screening with low dose helical computed tomography (LDCT) may decrease lung cancer mortality, which brings hope for the early diagnosis and treatment of lung cancer. In recent years, great progresses have been made on research of lung cancer screening with LDCT. However, whether LDCT could be applied to large population-based lung cancer screening projects is still under debate. In this paper, we review the recent progresses on history of lung cancer screening with LDCT, selection of high-risk individuals, management of pulmonary nodules, performance of screening, acceptance of LDCT and cost-effectiveness.
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Toward adaptive proton therapy guided with a mobile helical CT scanner.

PURPOSE: To evaluate the feasibility of image-guided adaptive proton therapy (IGAPT) with a mobile helical-CT without rails. METHOD: CT images were acquired with a 32-slice mobile CT (mCT) scanning through a 6 degree-of-freedom robotic couch rotated isocentrically 90 degrees from an initial setup position. The relationship between the treatment isocenter and the mCT imaging isocenter was established by a stereotactic reference frame attached to the treatment couch. Imaging quality, geometric integrity and localization accuracy were evaluated according to AAPM TG-66. Accuracy of relative stopping power ratio (RSPR) was evaluated by comparing water equivalent distance (WED) and dose calculations on anthropomorphic phantoms to that of planning CT (pCT). Feasibility of image-guided adaptive proton therapy was demonstrated on fractional images acquired with the mCT scanner. RESULTS: mCT images showed slightly lower spatial resolution and a higher contrast-to-noise ratio compared to pCT images from the standard helical CT scanner. The geometric accuracy of the mCT was <1 mm. Localization accuracy was <0.4 mm and <0.3° with respect to 2DkV/kV matching. WED differences between mCT and pCT images were negligible, with discrepancies of 0.8 ±â€¯0.6 mm and 1.3 ±â€¯0.9 mm for brain and lung phantoms respectively. 3D gamma analysis (3% and 3 mm) passing rate was >95% on dose computed on mCT, with respect to dose calculation on pCT. CONCLUSION: Our study has demonstrated that the geometric integrity, image quality and RSPR accuracy of the mCT are sufficient for IGAPT.

CT angiography after 20 years: a transformation in cardiovascular disease characterization continues to advance.

Through a marriage of spiral computed tomography (CT) and graphical volumetric image processing, CT angiography was born 20 years ago. Fueled by a series of technical innovations in CT and image processing, over the next 5-15 years, CT angiography toppled conventional angiography, the undisputed diagnostic reference standard for vascular disease for the prior 70 years, as the preferred modality for the diagnosis and characterization of most cardiovascular abnormalities. This review recounts the evolution of CT angiography from its development and early challenges to a maturing modality that has provided unique insights into cardiovascular disease characterization and management. Selected clinical challenges, which include acute aortic syndromes, peripheral vascular disease, aortic stent-graft and transcatheter aortic valve assessment, and coronary artery disease, are presented as contrasting examples of how CT angiography is changing our approach to cardiovascular disease diagnosis and management. Finally, the recently introduced capabilities for multispectral imaging, tissue perfusion imaging, and radiation dose reduction through iterative reconstruction are explored with consideration toward the continued refinement and advancement of CT angiography.

Coronariografía mediante tomografía computarizada con sincronización prospectiva. Comparación de la calidad de imagen y dosis de radiación con equipos de 128 detectores de fuente única y doble fuente / Coronary CT angiography using a prospective protocol. Comparison of image quality and radiation dose between dual source CT and single source CT

Objetivo. Comparar la calidad de imagen y la dosis de radiación de un grupo de pacientes a los que se les realizó una coronariografía mediante tomografía computarizada helicoidal de doble fuente (TCDF) de 128 cortes con pitch alto y adquisición prospectiva, con la calidad de imagen y la dosis de radiación de un grupo de pacientes con similares características clínicas a los que se les realizó una coronariografía por tomografía computarizada de fuente única (TCFU) de 128 cortes con adquisición secuencial prospectiva. Material y métodos. Se incluyeron 80 pacientes con una frecuencia cardíaca <= 65 lat/min: a 40 de ellos se les realizó una tomografía computarizada (TC) secuencial de fuente única de 128 cortes y sincronización prospectiva, y a los 40 restantes se les realizó una TC helicoidal de doble fuente de 128 cortes, con pitch alto y sincronización prospectiva. Dos radiólogos evaluaron de manera independiente la calidad de imagen de las arterias coronarias de 80 estudios de coronariografía por TC (CTC) empleando una escala de 1 a 4 (en la que 1 es imagen de excelente calidad y 4 calidad deficiente). También se calculó la dosis de radiación efectiva. Resultados. Ambos grupos presentaban características clínicas similares. La calidad de imagen del grupo de TCDF fue significativamente mayor que la del grupo de TCFU (p = 0,006). La dosis media de radiación efectiva del grupo de TCDF fue significativamente más baja que la del grupo de TCFU (1,4 ± 0,6 mSv frente a 2,2 ± 0,9 mSv; p < 0,01), lo que representa una reducción de dosis del 36% en el primer grupo. Conclusión. Aunque tanto la TC secuencial de fuente única de 128 cortes con adquisición prospectiva como la TC helicoidal de doble fuente de 128 cortes con pitch alto y adquisición prospectiva presentan una calidad de imagen alta con dosis de radiación efectiva bajas, la TC helicoidal de doble fuente de 128 cortes y adquisición prospectiva proporciona una mejor calidad de imagen y una dosis de radiación efectiva menor (AU)

Objective. To compare the image quality and radiation dose in a group of patients undergoing coronary CT angiography using a 128-slice dual source helical CT scanner with high pitch alto and prospective acquisition with those in a group of patients with similar clinical characteristics undergoing coronary CT angiography using a 128-slice single-source CT scanner with prospective sequential acquisition. Material and methods. We included 80 patients with heart rates <=65 beats/min: 40 underwent sequential 128-slice single source CT with prospective synchronization and the other 40 underwent 128-slice dual source helical CT with high pitch and prospective synchronization. Two radiologists independently assessed the quality of the images of the coronary arteries on the 80 coronary CT angiograms: image quality was classified on a four-point scale in which 1 represented excellent and 4 deficient. The effective dose of radiation was also calculated. Results. The clinical characteristics of the patients in the two groups were similar. The image quality obtained with dual source CT was significantly better than that obtained with single source CT (P=0.006). The mean effective dose of radiation in the group undergoing dual source CT was 36% lower than in the group undergoing single source CT (1.4±0.6 mSv vs. 2.2±0.9 mSv; P<0.01). Conclusion. Although both sequential 128-slice single source CT with prospective acquisition and 128-slice dual source helical CT with high pitch and prospective acquisition provide good image quality and low effective doses of radiation, 128-slice dual source helical CT with prospective acquisition provides better image quality and results in a lower effective dose of radiation (AU)

Aproximación al diagnóstico radiológico de las neumonías intersticiales idiopáticas. Hallazgos en tomografía computarizada de alta resolución / Radiological diagnostic approach to idiopathic interstitial pneumonias: findings in high resolution computed tomography

Las neumonías intersticiales idiopáticas, cuyos hallazgos histológicos y radiológicos revisamos, se incluyen entre las enfermedades difusas del parénquima pulmonar y, aunque pueden afectar a otros compartimentos, el intersticio pulmonar es el sustrato inicial de la lesión del parénquima por diversos patrones de inflamación y fibrosis. La clasificación actual, propuesta en 2002 como un documento de consenso internacional multidisciplinario auspiciado por la American Thoracic Society y la European Respiratory Society incluye 7 entidades. Basada en criterios histológicos, cada patrón histológico se asocia con un patrón de imagen. Son un grupo de entidades de etiología desconocida con características comunes y rasgos diferenciales que permiten individualizarlas como enfermedades con pronóstico y tratamiento diferentes. Como formas idiopáticas son infrecuentes, pero comparten sustrato morfológico con otras enfermedades de causa conocida más frecuentes, que es necesario excluir para alcanzar el diagnóstico definitivo. Por ello, es importante que el radiólogo esté familiarizado con sus hallazgos de imagen característicos (AU)

A review is presented on the histological and radiological findings in idiopathic interstitial pneumonias, which are included among the diffuse parenchymal lung diseases. Although they may affect other compartments, the lung interstitium is the initial substrate of the parenchymal lesion due to different patterns of inflammation and fibrosis. The current classification, proposed in 2002 as an international multidisciplinary consensus document promoted by the American Thoracic Society and the European Respiratory Society, includes 7 conditions. Based on histological criteria, each histological pattern is associated with an image pattern. They are a group of conditions of unknown origin with common characteristics and differential features that enable them to be individualised as diseases with a different prognosis and treatment. They are rare as idiopathic forms, but share a morphological substrate with other more common diseases of unknown cause, which means they have to be excluded to reach a definitive diagnosis. For this reason it is important that the radiologist is familiar with their characteristic imaging finding (AU)

Radiation dose from coronary CT angiography: five years of progress.

Radiation doses from coronary CT angiography have been scrutinized as a consequence of rising concern over cumulative lifetime radiation dose from diagnostic imaging and potential cancer risk. In response to this, the past 5 years have witnessed progressive refinements in CT technology and new dose reduction protocols, including electrocardiography-based tube current modulation, lower peak tube voltage, prospective or axial scanning, high-pitch spiral scanning, and iterative CT data reconstruction. As a direct result, compared with radiation exposure levels initially reported from 64-detector coronary CT angiography without dose modulation (range, 16-20 mSv), doses have decreased by approximately 50% every 2 years since 2005. Recent high-pitch spiral scan studies have documented doses ≤ 1 mSv. In routine clinical practice, registries show somewhat higher radiation dose levels, but nonetheless a similar rate of improvement with marked dose reduction enabled by dissemination of updated CT scanner technology. The current challenge is to continue the past rate of progress by incorporating research into practice and to facilitate improved technology.

U.S. primary care physicians' lung cancer screening beliefs and recommendations.

BACKGROUND: No high-quality study to date has shown that screening reduces lung cancer mortality, and expert groups do not recommend screening for asymptomatic individuals. Nevertheless, lung cancer screening tests are available in the U.S., and primary care physicians (PCPs) may have a role in recommending them to patients. PURPOSE: This study describes U.S. PCPs' beliefs about and recommendations for lung cancer screening and examines characteristics of PCPs who recommend screening. METHODS: A nationally representative survey of practicing PCPs was conducted in 2006-2007. Mailed questionnaires were used to assess PCPs' beliefs about lung cancer screening guidelines and the effectiveness of screening tests and to determine whether PCPs would recommend screening for asymptomatic patients. Data were analyzed in 2009. RESULTS: Nine hundred sixty-two PCPs completed the survey (absolute response rate=70.6%; cooperation rate=76.8%). One quarter said that major guidelines support lung cancer screening. Two thirds said that low-radiation dose spiral computed tomography (LDCT) screening is very or somewhat effective in reducing lung cancer mortality in current smokers; LDCT was perceived as more effective than chest x-ray or sputum cytology. Responding to vignettes describing asymptomatic patients of varying smoking exposure, 67% of PCPs recommended lung cancer screening for at least one of the vignettes. Most PCPs recommending screening said they would use chest x-ray; up to 26% would use LDCT. In adjusted analyses, PCPs' beliefs and practice style were strongly associated with their lung cancer screening recommendations. CONCLUSIONS: Many PCPs' lung cancer screening beliefs and recommendations are inconsistent with current evidence and guidelines. Provider education regarding the evidence base and guideline content of lung cancer screening is indicated.

Pancreatic insulinoma: current issues and trends.

BACKGROUND: Although insulinomas are very rare tumors, they are the most common pancreatic neuroendocrine neoplasms. The incidence in general population is 1-4 per 1,000,000 yearly but the incidence is higher in autopsy studies. The malignancy of insulinomas is difficult to be predicted on the basis of their histological features, and the current WHO classification has been re-evaluated. This review aimed to summarize classical knowledge with current trends in the diagnosis and treatment of insulinomas. DATA SOURCES: A Medline search using terms "insulinoma", "treatment" and "neuroendocrine tumors" was conducted. Additional references were sourced from key articles. RESULTS: Surgery is the treatment of choice for insulinoma and has an extremely high success rate. Medical treatment is also available but only for patients who are unable or unwilling to undergo surgical treatment. Preoperative localization is necessary for planning the surgical approach. Many methods exist for localization of an insulinoma and can be invasive and non-invasive. The combination of biphasic thin section helical CT and endoscopic ultrasonography (EUS) has an almost 100% sensitivity in localizing insulinomas. Laparoscopic ultrasound is mandatory to localize intraoperatively these tumors. EUS-guided fine needle tattooing is an alternative method of localization in case of lack of laparoscopic ultrasound. CONCLUSION: Laparoscopic resection for benign insulinomas is the procedure of choice, whereas pancreatectomy is reserved for large, potentially malignant tumors.

The present state of coronary computed tomography angiography a process in evolution.

In the past 5 years since the introduction of 64-detector row cardiac computed tomography angiography (CCTA), there has been an exponential growth in the quantity of scientific evidence to support the feasibility of its use in the clinical evaluation of individuals with suspected coronary artery disease (CAD). Since then, there has been considerable debate as to where CCTA precisely fits in the algorithm of evaluation of individuals with suspected CAD. Proponents of CCTA contend that the quality and scope of the available evidence to date support the replacement of conventional methods of CAD evaluation by CCTA, whereas critics assert that clinical use of CCTA is not yet adequately proven and should be restricted, if used at all. Coincident with the scientific debate underlying the clinical utility of CCTA, there has developed a perception by many that the rate of growth in cardiac imaging is disproportionately high and unsustainable. In this respect, all noninvasive imaging modalities and, in particular, more newly introduced ones, have undergone a higher level of scrutiny for demonstration of clinical and economic effectiveness. We herein describe the latest available published evidence supporting the potential clinical and cost efficiency of CCTA, drawing attention not only to the significance but also the limitations of such studies. These points may trigger discussion as to what future studies will be both necessary and feasible for determining the exact role of CCTA in the workup of patients with suspected CAD.

Aplicações da tomografia computadorizada em Ortodontia: "o estado da arte" / Computed tomography applications in Orthodontics: the state of the art

O objetivo deste artigo é informar, ao ortodontista e ao pesquisador, sobre o atual estágio de desenvolvimento tecnológico das imagens craniofaciais geradas por Tomografia Computadorizada Helicoidal Multislice (TC Multislice) e por Tomografia Computadorizada de Feixe Crônico (TCFC), bem como suas aplicações em Ortodontia, Ortopedia Facial e Cirurgia Ortognática. Pretende-se apresentar as múltiplas aplicações clínicas e potenciais para pesquisas científicas das imagens tridimensionais (3D-TC) em Ortodontia. Como as modalidades atuais de tratamento ortodôntico estão se tornando mais sofisticadas, a necessidade de registros tridimensionais (3D) precisos dos pacientes se torna cada vez mais crítica, e a adoção da TCFC em conjunto com a TC Multislice levará os ortodontistas a uma mudança de paradigma com relação aos meios de diagnóstico por imagem, inclusive com potenciais alterações nos planejamentos dos tratamentos ortodônticos e ortodôntico-cirúrgicos.

Assessing ischemic heart disease in patients with left bundle branch block--an emerging role for multislice computed tomography.

Diagnosis of left bundle branch block (LBBB) with concomitant coronary artery disease (CAD) alters the prognosis and the therapeutic management. All common non-invasive stress tests have a limited performance to identify CAD in patients with LBBB. Thus invasive coronary angiography is often needed to confirm or defer obstructive CAD. We propose a new diagnostic algorithm in evaluation of symptomatic and asymptomatic patients with LBBB.

A new method for measurement of left atrial volumes using 64-slice spiral computed tomography: comparison with two-dimensional echocardiographic techniques.

BACKGROUND: Left atrial (LA) volume, is related to cardiovascular morbidity. LA enlargement is usually assessed using trans-thoracic echocardiography (TTE). The association of modern multislice computed tomography (MSCT) imaging and new 3D reconstruction software, allows direct cardiac chamber volume measurement without geometrical assumptions. This study was designed to evaluate the maximal (LAmax) and minimal (LAmin) LA volumes during the cardiac cycle using MSCT and TTE approaches. METHODS: We screened 26 consecutive patients referred for coronary imaging using a 64-MSCT scanner and a TTE within 12 h. Contiguous multiphase images were generated from axial MSCT data and semi-automated 3D segmentation technique was applied to generate LA volumes. Using TTE, LA volumes and LA ejection fraction (LAEF) were obtained using five assumptions methods: cubing equation, diameter-length formula, area-length formula, ellipsoidal formula and biplane Simpson rule. RESULTS: Five patients were excluded for inadequate TTE visualization and one for ectopic beats during MSCT. The sample consisted in 20 patients (11 men, age: 56+/-14 years). Using MSCT, LA volumes indexed to body surface area were: LAmax=74+/-27 ml/m(2), LAmin=49+/-26 ml/m(2), with close correlations with TTE measurements and a significant underestimation by all TTE approaches. A close correlation was observed between LAEF using MSCT and TTE Simpson's method: 36+/-14% vs. 37+/-14%, r=0.99, p<0.0001. CONCLUSION: Theses results suggest that the assessment of LA volumes and ejection fraction was reliable using 64-MSCT in patients referred for coronary computed tomography imaging.

Technological approaches to in-room CBCT imaging.

The use of Cone-Beam Computed Tomography (CBCT) in Image-Guided Radiation Therapy (IGRT) has become increasingly feasible and popular in recent years. Advances and developments in Flat-Panel Imager (FPI) technology and image reconstruction software allow for linac-mounted 3D CBCT imaging. Taking CBCT images on a daily/weekly basis, offers the possibility to guide the treatment beam according to tumour motion and to apply changes to the treatment plan if necessary. This however raises the issue of additional imaging dose and thus increases in secondary cancer risk. The performance characteristics of kV-CBCT and MV-CBCT solutions currently offered by Elekta, Siemens and Varian are compared in this paper in terms of additional imaging dose and image quality. The review also outlines applications of CBCT for IGRT and Adaptive Radiotherapy (ART). As CBCT is not the only in-room IGRT platform, helical MV-CT (Tomotherapy) and in-room CT designs are also presented.

Multidetector spiral CT arthrography of the shoulder. Clinical applications and limits, with MR arthrography and arthroscopic correlations.

Although MR imaging and MR arthrography are the first choice modalities for shoulder imaging, CT arthrography (CTA) may be used successfully to address many clinical questions. The advent of submillimeter multiple detector CT technology and subsequent excellent three-plane resolution has considerably increased the quality of CTA examinations and has propelled this technique to the forefront in a growing number of indications. The combined use of iodinated contrast material for fluoroscopic confirmation of the articular position of the needle before injection of gadolinium chelates for MR arthrography offers the unique opportunity to compare CTA and MRA findings in carefully selected cases. This paper illustrates capabilities and limits of CTA for the study of rotator cuff tears, shoulder instability, cartilage lesions, anatomical variants and abnormalities of the glenoid labrum, with correlations to MR arthrography and surgical findings.