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The echocardiographic-fluoroscopic fusion imaging tool is able to acquire imaging data from both fluoroscopy and transesophageal images and co-register and align them in the three-dimensional space and time by putting onto the same coordinate system. In this way the soft tissues that are well visualized by echocardiography and the metallic materials (catheters and devices), better imaged by fluoroscopy, are displayed in the standard fluoroscopic projections in a hybrid image in real time. In this review, we describe the basic technical aspects and its main applications in transcatheter structural heart interventions.

Cardiac magnetic resonance is an accurate and versatile tool for multiparametric morphologic and functional evaluation of the heart and great vessels, with a wide range of clinical applications: from acute and chronic ischemic heart disease to the assessment of the substrate of complex ventricular arrhythmias and the follow-up of patients with valvular and congenital heart disease. The accuracy in cardiac volume and ejection fraction quantification, tissue characterization, valvular regurgitant fraction and cardiac shunt assessment, pharmachologic stress myocardial perfusion and three-dimensional reconstruction of great vessels are the points of strength that have made Cardiac magnetic resonance an invaluable tool for diagnostic, classification and follow-up of patients with various cardiac diseases.

Purpose: Coronary angiography with multidetector-row computed tomography (MDCT-CA) allows quantification of coronary artery stenosis with a high level of accuracy; however, a better estimation of stenosis can be achieved by using appropriate reformatting filters, especially in stents and calcified segments. Quantitative computed tomography angiography (QCTA) is intended to overcome the limitations of the visual score. The aim of this study was to evaluate the accuracy of QCTA with different filters in comparison with quantitative coronary angiography (QCA) and visual score., Materials and Methods: Two blinded operators visually scored 17 consecutive patients referred for MDCT-CA with a per-segment analysis. The degree of stenosis was classified as 0-20%, 20-50% (wall irregularities), 50-70% (significant disease) and 70-100% (vessel occlusion). Each segment was then analysed using the electronic callipers of the QCTA system with 15 different filters. No contour editing was performed. Data were compared with QCA and conventional coronary angiography (CCA). Comparison between QCTA, visual score and QCA were performed using Spearman's rank correlation., Results: Of 25 segments analysed (mean 1.4 diseased segment per patient), 375 measurements were considered. Good correlation was found between the visual score and QCA [Pearson correlation coefficient (rho=0.852; p<0.0001)] and between QCA and CCA (rho=0.804; p<0.0001). Moderate correlation was found between QCA and QCTA only using two filters (rho=0.444; p<0.0001 for YA filter and rho=0.450; p<0.0001 for YB filter)., Conclusions: Overall QCTA accuracy is low if contour editing is not applied, especially in calcified vessels. Certain filters can help to better estimate the exact percentage of stenosis.

Soft tissue calcinosis is a common radiographic finding, which may be related to different types of pathological processes. Multimodality imaging, combined with analysis of clinical and laboratory data, plays an important role for the differential diagnosis of these conditions. Conventional radiography is considered the first line approach to soft tissue calcinosis; CT and MRI may provide further information to better characterize calcified deposits. Imaging may help to distinguish metabolic calcification, such as primary tumoral calcinosis and the secondary one (associated with acquired disorders of calcium or phosphate regulation), from dystrophic calcification, which is associated to normal blood values of phosphate. The sedimentation sign typical of tumoral calcinosis has been demonstrated by plain film radiography, CT, MRI, and, more recently, by ultrasonography. Other types of soft tissue calcinosis may have a degenerative, metaplastic or neoplastic origin, and their characterization strongly relies on multimodality imaging.

Purpose: This study was done to evaluate the variability of semiautomated volume measurements of solid pulmonary nodules between two different versions of the same volumetric software., Materials and Methods: The volumes of 100 solid intraparenchymal nodules (mean volume 88.10 mm(3); range 7.36-595.25 mm(3)) studied with the same multidetector computed tomography (MDCT) protocol were determined using two different versions of the same volumetric software (LungCARE 2006G and LungCARE 2007S). The 2006G version is based on a single-segmentation algorithm, whereas the newer version features two algorithms: SmallSizeNodule and AllSizeNodule. The results obtained with the 2006G version were compared with those of the 2007S version with the SmallSizeNodule algorithm, as recommended by the user manual. In addition, we compared the volumetric measurements obtained by the two different algorithms of the 2007S version., Results: The 2006G version and the 2007S version with the SmallSizeNodule algorithm agreed in only two of 100 cases and showed a mean variability of 1.66% (range 0%-8.78%). A more significant volumetric discrepancy was observed between the two different algorithms of the 2007S version, with the AllSizeNodule algorithm providing on average larger volumes (mean variability 71.08%; range 6.02%-218.80%) than SmallSizeNodule. Volume discrepancies were more pronounced in the subgroups of smaller nodules in all comparisons., Conclusions: There is variability also in the results provided by different versions of the same volumetric software, and this may affect the calculation of the nodule-doubling time. Computer-aided assessment of the growth of lung nodules should always be performed using the same version of volumetric software and the same segmentation algorithm.

Purpose: To evaluate the influence of slice thickness, reconstruction algorithm and tube current (mA) on the performance of a software package in determining the volume of solid pulmonary nodules on multidetector-row computed tomography (MDCT)., Materials and Methods: A chest phantom containing artificial solid nodules with known volume was imaged with two MDCT scans at 100 and 40 mAs (200 mA and 80 mA, 0.5-s rotation time), respectively. Data were reconstructed with slice thicknesses of 1.25 and 2.5 mm and five different algorithms. The volumes of three nodules (juxtavascular, intraparenchymal, juxtapleural) were calculated using three-dimensional (3D) volumetric software. Differences between estimated and real volume were reported for each nodule and reconstruction set., Results: The software segmented all nodules on 1.25-mm-thick reconstructions, independently from the mAs. It did not segment the juxtapleural nodule on 2.5-mm-thick reconstructions at 40 mAs. Mean values of the differences, which better approximated the real volume of the nodules, were obtained with high-spatial-resolution algorithms on both 100 and 40 mAs images at 1.25-mm slice thickness., Conclusions: Slice thickness, reconstruction algorithm and tube current can affect the 3D volume measurement of solid nodules. The best performance of the software, on both 100 and 40 mAs images, was observed with a slice thickness of 1.25 mm and high-spatial-resolution algorithms.

Quality of service, in terms of improvement in patient satisfaction, is an increasingly important objective in all medical fields, and is especially imperative in orthodontics due to the high numbers of patients treated. Information technology can provide a meaningful contribution to bettering treatment processes, and we maintain that systems such as CAD, CAM and CAE, although initially conceived for industrial purposes, should be evaluated, studied and customized with a view to use in medicine. The present study aims to evaluate Reverse Engineering (RE) and Rapid Prototyping (RP) in order to define an ideal chain of advanced technological solutions to support the critical processes of orthodontic activity.

Aim: Multi-headvariable-geometry gammacamera, allow us to carry out multi-dimensional scintigraphic single photon emission computed tomography (SPECT) studies, with the possibility of creating coronal, axial, sagittal, three-dimensional images like the last generation of multi-slice RMI or multislice CT scan. The aim of this paper is to weigh up the reconstruction parameters to apply in [(0111)In]Pentetreotide scintigraphy for evaluating neuroendocrine tumors and try to standardize them., Methods: We have studied a group of 93 patients suffering from neuroendocrine tumors. Examination was carried out after administration of [111In] Pentetreotide with whole body and static acquisitions after 4 and 24 h, followed by SPECT acquisitions of head, thorax and abdomen after 24 h., Results: The results obtained show that the Filtered Back Projection using Butterworth filter can produce images of greater resolution than the iterative reconstruction method. Moreover, the reconstruction parameters are easily standardizable for head and thorax while for the abdomen the choice of these parameters is more difficult., Conclusions: Our data show that filtered back projection with Butterworth filter is the best procedure to carry out a SPECT examination with [111In] Pentetreotide.

Purpose: The aim of this study was to compare computed tomography angiography (CTA) sliding-thin-slab (STS) multiplanar reformatting (MPR), STS maximum intensity projection (MIP) and three-dimensional (3D) volume rendering (VR) reformatting techniques in the evaluation of cervicocranial arteries., Materials and Methods: Twenty patients examined with multislice CT were included in this study. CTA images were reformatted as STS-MIP, STS-MPR and 3DVR in orthogonal planes and in the oblique-coronal plane. Images were evaluated in consensus by two radiologists, with a third radiologist to resolve discordances in grading image quality parameters. The Spearman correlation analysis was performed to compare results and to obtain the correlation between scores resulting from the evaluation of parameters considered with the different techniques used (STSMIP, STS-MPR and 3DVR)., Results: STS-MIP images were significantly superior to STSMPR images for all parameters considered (p<0.05). Obliquecoronal 3DVR images were significantly superior to obliquecoronal STS-MIP images in the evaluation of vertebrobasilar vessels (p<0.05); in all other cases, 3DVR images were equivalent to STS-MIP images., Conclusion: STS-MIP images should be the primary reformatting technique for CTA of the cervicocranial arteries in addition to viewing the source images; 3DVR images can play an important role after a previsional diagnosis is made on the STS-MIP images.

Purpose: The aim of this study was to assess the feasibility of three-dimensional (3D) reconstructions and quantitative analysis of the volume of each component of the lung with cystic fibrosis (CF)., Materials and Methods: Twenty-two patients with CF (mean age 17+/-8 years) were included in the study. The patients underwent an unenhanced single-slice spiral computed tomography (CT) chest scan with the following parameters: collimation 3 mm, table feed 6 mm x rot(-1), reconstruction interval 1 mm, soft tissue reconstruction kernel. Four image data sets were obtained: native axial slices, cine-mode display, virtual bronchographic volume-rendered images with algorithm for tissue transition display and virtual endoluminal views. The lungs were segmented manually from the hilum to the visceral pleura on the axial images, and the entire lung volume was calculated. A histogram was generated representing the fractional volume of tissues, the density of which was within a preset range. A curve was then obtained from the histogram., Results: Native axial images and cine-mode display allowed complete evaluation of lung volumes. Virtual bronchography allowed a better assessment of the distribution of bronchiectasis. Virtual bronchoscopy was limited by the fact that it visualised only the surface, without differentiating mucus from the bronchial wall. Manual segmentation and generation of density-volume curves required 41+/-7 min for each lung. Three curve patterns were identified depending on disease severity., Conclusions: Volume-density analysis of lungs with CF is feasible. Its main advantage is that image analysis is not analogical, as the assessment is not performed using scoring systems or similar ordinal scales. This technique cannot differentiate acute from chronic findings, and the predictive value of the curve should be assessed.

In this study we evaluated different radiographic exams for the localization of impacted maxillary canines (orthopantomography (OPT), laterolateral and posteroanterior teleradiography, parallax method, laterolateral, occlusal radiography, computerized axial tomography, cone beam CT) highlighting the advantages and disadvantages of each. Four patients with impacted maxillary canines underwent selected radiographic investigations which allowed us to discuss their potential in identifying the position relative to the impacted teeth in the upper jaw. It was not possible to carry out all methods on the same patient as the level of radiation exposure experienced by each patient would too high and therefore unethical. Each method revealed the position of the canine with respect to the adjacent structures and the inclination of the major axis of the impacted tooth with respect to the plane of reference. We then evaluated the ease of use, the dosage of radiation emitted, the significance of the localization of the impacted canine, the immediacy of availability of the information required and the cost of each method. Each technique presented intrinsic advantages and limitations; however CBCT provides elements which escape during traditional radiographic analysis and is therefore indicated in case of impacted teeth or cranio-facial structural anomalies.

Purpose: The purpose of this study was to test the reproducibility of the three-dimensional (3D) Advanced Lung Analysis software (3D-ALA, GE Healthcare) in the estimation of pulmonary nodule volume., Materials and Methods: We retrospectively reviewed the unenhanced multislice CT scans (Lightspeed Pro 16 GE) of 77 patients with a solitary pulmonary nodule (n=71) or metastatic pulmonary disease (n=6). A total of 103 pulmonary nodules (19 well-circumscribed, 45 juxtavascular and 39 juxtapleural) were analysed grouped into five classes based on diameter: <5 mm, 10 nodules (9.7%); >or=5 to <10 mm, 25 nodules (24.2%); >or=10 mm to <15 mm, 41 nodules (39.8%); >or=5 to <18 mm, 14 nodules (13.6% ); >or=8 to <30 mm, 13 nodules (12.62%). The following acquisition parameters were used: slice thickness 0.625 mm, reconstruction interval 0.4 mm, pitch 0.562:1, 140 kV, 300 mAs, field of view 13 cm, bone kernel. For each of the 103 nodules three, 3D volume measurements were obtained by the 3D-ALA software. The reproducibility of nodule segmentation was evaluated according to a visual score (1=optimal, >or=95%; 2=fair, 90-95%; 3=poor, 0.05)., Conclusions: Three-dimensional volume measurement with ALARiassunto 1 software is reproducible for all nodules as regards dimension and site. ALA-1 software provided a good and reproducible volume measurement in well-circumscribed and most juxtavascular nodules. Volumetric evaluation and reproducibility of volume estimation in juxtapleural pulmonary nodules, particularly those adjacent to diaphragmatic pleura, is inadequate, and software improvement is needed.

Conventional coronary angiography is the gold standard for the diagnosis of coronary artery anomalies. Coronary anomalies are relatively rare findings in patients undergoing conventional coronary angiography for suspected obstructive coronary artery disease. Recently, the increasing performance of diagnostic techniques, such as electron beam tomography (EBT), magnetic resonance (MR) and, more recently, multislice computed tomography (MSCT), has enabled their application to cardiac imaging. MSCT, in particular, has a prominent role in coronary imaging due to its spatial and temporal resolution and three-dimensional capabilities. We report the incidence and pathophysiology of coronary artery anomalies based on the capabilities of recent diagnostic tools with the aim of improving an accurate and noninvasive diagnostic approach.

This paper describes the state of the art of tractography, a technique which enables the virtual reconstruction of axon bundles of the central nervous system using diffusion-weighted magnetic resonance images. This technique has raised enthusiasm and expectations among specialists because it is the only non-invasive method for studying the three-dimensional architecture of axonal fibres in vivo. Tractography is a new technique used to assess the anatomy of the central nervous system, and it will be available for routine clinical use in the future. Understanding its potential applications and limitations is therefore important.

Purpose: Magnetic resonance angiography (MRA) has recently become instrumental in the diagnosis of arterial disease in various body districts and is gaining an increasingly important role in the study of peripheral vascularisation. The aim of our study was to evaluate the reliability of MRA using digital subtraction angiography (DSA) as the reference standard., Materials and Methods: Between November 2003 and August 2004, 30 patients with known peripheral arterial disease were studied by MRA and DSA. MRA was performed with a Philips Intera 1.5 T, with acquisitions from the coeliac trunk to the feet. For acquisitions of the feet and ankles we used unenhanced time-of-flight (TOF) sequences with a head coil. The angiographic sequence was acquired in three volumes of 40-45 cm after administration of paramagnetic contrast material., Results: In the patients with peripheral arterial disease, the technique provided a precise evaluation of the stenosis (mild, moderate, severe) or obstruction of the peripheral district as well as the detection of other diseases, such as stenosis of the renal arteries or aneurysms., Conclusions: Total-body three-dimensional (3D) MRA allows a fast, safe, and accurate assessment of the arterial system in patients with arteriosclerosis and can be considered an alternative to DSA in the management of patients with steno-obstructive disease of the peripheral arteries.

Purpose: The purpose of this study was to determine whether the double arterial phase with multidetector computed tomography MDCT and high-iodine-concentration contrast material (CM) improves identification of hepatocellular carcinoma (HCC)., Materials and Methods: Fifty patients with 111 HCC foci (61 confirmed histologically, 46 confirmed by percutaneous interventional procedures, four confirmed by CT follow-up of at least 6 months) underwent MDCT with a double arterial phase and a portal venous phase after administration of contrast material with a high iodine concentration (400 mgI/ml, 2 ml/kg, 5 ml/s). Two radiologists independently evaluated the images in three distinct reading sessions (early arterial phase (EAP), late arterial phase (LAP) and double arterial phase) to determine presence, number and degree of suspicion of HCC. The sensitivity and the positive predictive value (PPV) were calculated for every reading session. The following statistical evaluations were used: k statistic and McNemar's test., Results: Mean sensitivity and PPV in the detection of HCC were, respectively, 83.8% and 93.5% for EAP, 90.5% and 94.8% for LAP, and 94.1% and 95.1% for the double arterial phase. Sensitivity of the double arterial phase was statistically higher when compared with EAP alone but showed no statistically significant difference when compared with LAP. The k values ndicated moderate-to-excellent interobserver agreement in all reading sessions., Conclusions: Sensitivity and PPV increase progressively when passing from EAP to LAP to double-arterial-phase images obtained with contrast material with a high iodine concentration. However, the difference in sensitivity between LAP and the double arterial phase was not statistically significant.

Unlabelled: Finishing in orthodontics can be challenging and can involve use of various techniques and armamentarium. This article reports a study that evaluates a procedure for using a thicker Aligner at the end of treatment to aide in finishing and also to determine if this would reduce the need for additional "case refinement" Aligners at the end of treatment., Background: Align Technology has developed the Invisalign System, which is a series of clear plastic appliances ("aligners") that move the patient's teeth in small increments from their original state to a final, treated state. The Invisalign System uses a computer as a tool to assist in creating a series of sequential movements to assure light and consistent forces on the patient's teeth.

Aim: To investigate the diagnostic accuracy of two different protocols for image evaluation used in multislice computed tomography coronary angiography (MSCT-CA)., Materials and Methods: Sixty patients with suspected coronary artery disease undergoing conventional coronary angiography (CA) were enrolled for MSCT-CA. All patients underwent 16-row MSCT (Sensation 16, Siemens, Germany) with the following parameters: detector rows 16, collimation 0.75 mm, gantry rotation time 375 ms. Two independent observers assessed the images for significant stenosis using a a protocol with standard projections and a three-dimensional protocol. The diagnostic accuracy for both methods was calculated using quantitative CA as a reference standard., Results: The sensitivity, specificity, negative predictive value and positive predictive value obtained with the conventional projection protocol and with three-dimensional protocol were: 54% and 93%, 97% and 97%, 76% and 86%, 92% and 99%, respectively., Conclusions: Conventional projections in the assessment of MSCT-CA provide insufficient diagnostic accuracy compared with three-dimensional processing.