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Background. Language disorders may occur in patients with disorders of consciousness (DoCs), and they could interfere with the behavioral assessment of consciousness and responsiveness. Objective. In this study, we retrospectively explored whether ERP N400 was eventually associated with the presence of aphasia diagnosed in those patients who had evolved into Exit-Minimally Conscious State (E-MCS) at the clinical follow-up. Methods. In this retrospective cohort study, the ERPs elicited by an auditory sentences task were retrospectively examined in a sample of 15 DoC patients diagnosed according to the Coma Recovery Scale-Revised (CRS-R). All these 15 DoC patients underwent a (at least) 1-year clinical follow-up, which included a neuropsychological evaluation to assess language function among other cognitive functions. Ten healthy individuals also underwent the same paradigm to investigate the variability of ERPs characteristics. Results. The N400 ERP component with centroparietal topography was found in 9 of 10 healthy controls in response to the ill-formed sentences. Analysis of patients' data revealed that (1) a significant N400 component could be detected in 64% (9 of 14 patients) of the DoC patients regardless of the type of DoC; (2) no significant N400 ERP component was retrospectively detected in those E-MCS patients who showed aphasia at the follow-up; and (3) the presence/absence of the N400-ERP component was consistent with the brain lesion side and significantly predict the recovery. Conclusion. These preliminary findings indicate that the absence of N400 was significantly associated with the presence of aphasia diagnosed at the clinical follow-up in E-MCS patients.

White matter hyperintensities (WMH) are brain areas of increased signal on T2-weighted or fluid-attenuated inverse recovery magnetic resonance imaging (MRI) scans. In this study we present a new semi-automated method to measure WMH load that is based on the segmentation of the intensity histogram of fluid-attenuated inversion recovery images. Thirty patients with mild cognitive impairment with variable WMH load were enrolled. The semi-automated WMH segmentation included removal of non-brain tissue, spatial normalization, removal of cerebellum and brain stem, spatial filtering, thresholding to segment probable WMH, manual editing for correction of false positives and negatives, generation of WMH map, and volumetric estimation of the WMH load. Accuracy was quantitatively evaluated by comparing semi-automated and manual WMH segmentations performed by two independent raters. Differences between the two procedures were assessed using Student's t-tests and similarity was evaluated using linear regression model and Dice similarity coefficient (DSC). The volumes of the manual and semi-automated segmentations did not statistically differ (t-value = -1.79, DF = 29, p = 0.839 for rater 1; t-value = 1.113, DF = 29, p = 0.2749 for rater 2), were highly correlated [R (2) = 0.921, F (1,29) = 155.54, p < 0.0001 for rater 1; R (2) = 0.935, F (1,29) = 402.709, p < 0.0001 for rater 2] and showed a very strong spatial similarity (mean DSC = 0.78, for rater 1 and 0.77 for rater 2). In conclusion, our semi-automated method to measure the load of WMH is highly reliable and could represent a good tool that could be easily implemented in routinely neuroimaging analyses to map clinical consequences of WMH.

Background: Conventional magnetic resonance imaging (MRI) has improved the diagnosis and monitoring of multiple sclerosis (MS). In clinical trials, MRI has been found to detect treatment effects with greater sensitivity than clinical measures; however, clinical and MRI outcomes tend to correlate poorly., Methods: In this observational study, patients (n = 550; 18-50 years; relapsing-remitting MS [Expanded Disability Status Scale score ≤4.0]) receiving interferon (IFN) β-1a therapy (44 or 22 µg subcutaneously [sc] three times weekly [tiw]) underwent standardized MRI, neuropsychological and quality-of-life (QoL) assessments over 3 years. In this post hoc analysis, MRI outcomes and correlations between MRI parameters and clinical and functional outcomes were analysed., Results: MRI data over 3 years were available for 164 patients. T2 lesion and T1 gadolinium-enhancing (Gd+) lesion volumes, but not black hole (BH) volumes, decreased significantly from baseline to Year 3 (P < 0.0001). Percentage decreases (baseline to Year 3) were greater with the 44 μg dose than with the 22 μg dose for T2 lesion volume (-10.2% vs -4.5%, P = 0.025) and T1 BH volumes (-7.8% vs +10.3%, P = 0.002). A decrease in T2 lesion volume over 3 years predicted stable QoL over the same time period. Treatment with IFN β-1a, 44 μg sc tiw, predicted an absence of cognitive impairment at Year 3., Conclusion: Subcutaneous IFN β-1a significantly decreased MRI measures of disease, with a significant benefit shown for the 44 µg over the 22 µg dose; higher-dose treatment also predicted better cognitive outcomes over 3 years.

The aim of this study was to assess the image display of a web-based teleradiology system that uses a common web browser and has no need of proprietary applets, plug-ins, or dedicated software for DICOM display. The teleradiology system (TS) is connected to the Internet by ADSL and to radiological modalities using the DICOM standard with TCP/IP. Images were displayed on a PC through Internet connection with the remote TS using a common web browser. MS lesion number and volume in T1- and T2-weighted images (T1w and T2w, respectively) of 30 brain MR studies were quantified using both the TS and a conventional software. Wilcoxon signed ranks test and intraclass correlation coefficient (ICC) were used to assess the variability and concordance between intra- and inter-observer and TS and conventional DICOM viewer, setting significance at p < 0.05. No significant differences in T1w and T2w volumes between the TS and the conventional software were found by either operator. The ICC results showed a high level of inter-operator agreement in volume estimation in T1w and T2w images using the two systems. Quantitative assessment of MS lesion volumes in T1w and T2w images with a user interface of a teleradiology system that allows the consultation by means of a common web browser, without the need for proprietary plug-ins, applets, or dedicated software for DICOM display showed no significant differences from, and almost complete agreement with, conventional DICOM viewers.

Diffuse axonal injury (DAI), associated with deafferentation and functional rearrangement, probably plays a role in the chronic phase of traumatic brain injury (TBI). DAI with a haemorrhagic component can be quantified using magnetic resonance imaging (MRI) thanks to the iron-based susceptibility effect of haemosiderin, which increases with magnetic field strength. The aim of this work was to compare conventional 1.5 Tesla and 3 Tesla MRI in the assessment of DAI in TBI patients. Eighteen TBI patients were submitted, in random order, to a 1.5T and a 3T MRI examination using standard gradient echo sequences. Both scans were always performed on the same day. DAI lesions with a haemorrhagic component were manually segmented and classified by anatomical location. The Wilcoxon and ANOVA tests were used for statistical analysis, significance being set at p<0.05. The results of this study showed that 3T MRI is almost twice as sensitive as 1.5T MRI in assessing DAI in terms of lesion number and volume. Differences between the two scanners were not significant in the posterior cranial fossa. High-field MRI enhances the assessment of DAI and may help to increase understanding of the mechanisms underlying subacute and chronic clinical, cognitive and behavioural changes in TBI patients.

Purpose: This study sought to correlate lesion volume in infratentorial areas using 3.0-T proton-density (PD)-weighted images with disability scales and appropriate functional system scores in patients with multiple sclerosis (MS)., Materials and Methods: We examined 20 consecutive patients (13 women and 7 men) with a median age of 47 years (range 26-70). Neurological examination included the Expanded Disability Status Scale and its functional systems, the Barthel Index (BI) and the Rivermead Mobility Index (RMI). MRI scans were performed on a system operating at 3.0 T using a quadrature birdcage head coil. Acquired images imported as Digital Imaging and Communication in Medicine (DICOM) files, and the region of interest (ROI) files were converted to Neuroimaging Informatics Technology Initiative (NIfTI) format and normalised to the Montreal Neurological Institute (MNI) standard template. An automated segmentation algorithm was used to distinguish between supratentorial and infratentorial areas. Normalisation to the magnetisation-prepared rapid acquisition with gradient echo (MPRAGE) T1-weighted sequence allowed lesion volume estimation in the different anatomical areas., Results: A significant correlation was found between infratentorial lesion volume and the sensory functional system score (rho=0.76, p=0.002). No significant correlation was found between supratentorial lesion volume and Expanded Disability Status Scale (EDSS), RMI and BI scores., Conclusions: The described method, by means of anatomical assignment of MS lesions, allows detection of significant correlation coefficients between clinical and MRI lesion burden in MS patients at the infratentorial level.

The subventricular zone (SVZ) is a region that lies immediately beneath the ependymal layer on the lateral wall of the lateral ventricles, and is separated from the caudate nucleus by a layer of myelin. It contains multipotent neural stem cells. The aim of this study was to investigate the tissue around the SVZ, with the hypothesis that multimodal MRI is able to highlight the progressive disruption of tissue caused by the neurodegenerative disease in this area. We combined volumetric and diffusion tensor (DTI) imaging using a 3T imager in a cross-sectional study including 30 patients with amnestic-mild cognitive impairment (a-MCI), 30 patients with Alzheimer's disease (AD) and 30 age- and gender-matched healthy controls (HC). Our data indicate that mean diffusivity (MD) values increase continuously from HC through a-MCI to AD in the bilateral SVZ, where most of the proliferating stem cells in the adult brain are located. This result was specific for the SVZ and could not be observed in other periventricular areas. Multimodal MRI, being able to highlight structural changes of microscopic tissue in humans in vivo, could represent a precious tool to complement histological studies of neurogenesis., ((c) 2009 Elsevier Ireland Ltd. All rights reserved.)

Neuroimaging is becoming an increasingly important means of detecting changes in biochemical, microstructural and functional patterns occurring during rehabilitation. In magnetic resonance imaging (MRI), "advanced techniques", such as functional MRI, relaxometry, diffusion tensor imaging and spectroscopy, are making it possible to investigate these changes in vivo, together with brain function. This review highlights how advances in the field of MRI can shed light on the relationship between cerebral reorganisation after focal damage and functional recovery, providing insights that might be translated into clinical benefits for patients.

Introduction: Previous studies have demonstrated that non-demented Parkinson's disease (PD) patients have particular difficulty in producing verbs in a word generation situation. Two alternative explanations for this deficit have been proposed: the "motor" theory (verbs as action representawcttions) and the "grammatical" theory (verbs as lexical category). The aim of this study was to investigate the "motor" theory by exploring the neuronal substrates of action-related word production., Methods: Event-related functional magnetic resonance with a 3T magnetic resonance imaging (MRI) was used to explore brain activity during two overt oral language tasks, i.e., object naming (ON) and generation of action-verbs (GenA), in 14 non-demented PD patients using a common set of object drawings. The objects used were either man-made objects (MMO) or manipulable biological objects (MBO). Stimuli and tasks were randomized across subjects. Neuroimaging data were analyzed using SPM2., Results: Reaction times in GenA(MBO) were significantly longer than in the other three conditions (ON(MBO), ON(MMO), GenA(MMO)). The distribution of brain activities associated with each condition resembled that reported in previous studies on healthy subjects using similar tasks; a comparison between GenA and ON revealed slight differences located above all in the premotor and prefrontal cortices, particularly as regards GeneA(MBO)>ON(MMO). Furthermore, we found positive correlations between the severity of the motor deficit (as assessed by the Unified Parkinson's Disease Rating Scale - UPDRS score) and brain activity, particularly during GenA(MBO), in the pre- and post-central gyri bilaterally, left frontal operculum, left supplementary motor area (SMA) and right superior temporal cortex., Conclusions: The direct comparison in our study of brain activity during the production of action-words and of object names did not reveal any major differences. However, our results point to a relationship between motor system dysfunction in PD and the extent of activation in verb generation, a task which implies in-depth processing of semantic representation of actions.

Magnetic resonance imaging (MRI) studies have highlighted the possibility to investigate brain iron content in vivo. In this study, we combined T2* relaxometry and automatic segmentation of basal ganglia based on T1-weighted images in healthy subjects, with the aim of characterizing age related changes in volume and iron-related relaxivity values (R2*) of these structures. Thirty healthy subjects underwent MR imaging at 3 Tesla. Mean R2* values and volumes were calculated for the selected subcortical structures (pallidum, putamen, thalamus and caudate nucleus). Our results showed a correlation between R2* values and iron concentration as calculated from published post-mortem data. Furthermore, we observed a shrinkage/iron increase with a different pattern in the anatomical regions selected in this work, suggesting that the age-related changes on these MR parameters are specific to the subcortical structure considered. In particular, the putamen demonstrated a decrease of volume and an increase of iron level, with the posterior region of this structure appearing more disposed to iron deposition. Our work suggests that combining volumetry and iron estimation in MRI permits to investigate in vivo neurophysiological and neuropathological changes of basal ganglia., ((c) 2009 Wiley-Liss, Inc.)

Background: Cognitive impairment is a common symptom of multiple sclerosis (MS), but the association between cognitive impairment and magnetic resonance imaging (MRI) disease measures in patients with relapsing-remitting (RR) MS is unclear., Objectives: To study the prevalence of cognitive impairment and its relation with MRI disease measures in mildly disabled patients with RRMS., Methods: Patients aged 18-50 years with RRMS (McDonald criteria) and an Expanded Disability Status Scale (EDSS) score or=3 cognitive tests) was present in approximately 20% of all patients and in the subgroup who underwent MRI. T2 hyperintense and T1 hypointense lesion volumes were significantly higher in patients with cognitive impairment (defined as impaired performance on at least three tests of the Rao's battery) than those without. EDSS score was also significantly higher in cognitively impaired than in cognitively preserved patients. Disease duration, depression, and years in formal education did not differ significantly between cognitively impaired and cognitively preserved patients. T2 lesion volume, performance intelligence quotient, and age were significant predictors of cognitive impairment in this population. Weak correlations were found between performance on individual cognitive tests and specific MRI measures, with T1 and T2 lesion volumes correlating with performance on most cognitive tests., Conclusions: Cognitive impairment occurs in approximately one-fifth of mildly disabled patients with MS and is associated with specific MRI disease measures. Assessment of cognitive function at diagnosis could facilitate the identification of patients who may benefit from therapeutic intervention with disease-modifying therapies to prevent further lesion development.

In this study, diffusion tensor imaging (DTI) and T(2)* multiechorelaxometry were combined in 30 healthy subjects at 3T, with the aim of characterizing the spatial distribution of relaxation rates in white matter (WM). Region of interest (ROI) analysis was performed in 23 different fiber tracts automatically defined in standard space. Spearman rank analysis was performed on regional values of T(2)*, fractional anisotropy (FA), and radial diffusivity (RD). A strong relationship was observed between the location and direction of fiber bundles and relaxation rates, and adjacent fiber bundles with similar orientation showed very different relaxation rates. Moreover, while relaxation rates varied largely between different fiber tracts, variation of the same parameter within the same anatomical fiber bundle across individuals was remarkably limited. The rich variability of relaxation rates in WM and their complex relationship with DTI data suggested that the two techniques might be sensitive to complementary characteristics of myelin structure. This has tremendous potential to allow for a more detailed understanding of brain development and pathology, in particular in the context of age-related cognitive decline., ((c) 2009 Wiley-Liss, Inc.)

"Aggressive" multiple sclerosis (MS) is still a challenging diagnosis, in spite of the relevant progresses concerning the comprehension of the disease mechanisms, especially through pathology studies and the advent of conventional magnetic resonance imaging (MRI). Some reviews have been already published on their clinical and therapeutical aspects, but no systematic review is available in literature about the neuroradiological features, using both conventional and advanced techniques. In particular, advanced MRI techniques, namely diffusion-weighted and tensor imaging, magnetization transfer imaging, and proton magnetic resonance spectroscopy, are giving new insights to find specific and appropriate radiological parameters that can help in targeting the diagnosis. We report a review of literature on the neuroradiological findings of aggressive forms of MS, focusing specifically on the role of advanced MRI techniques in the diagnostic phase and during follow-up.

Purpose: This study sought to assess the role of multislice computed tomography (MSCT) in patients with suspected chronic mesenteric ischaemia (CMI)., Materials and Methods: Forty-five patients (29 men; mean age 68) underwent MSCT angiography of the abdomen for suspected CMI (main clinical finding: postprandial abdominal pain). The scan protocol was detectors/collimation 16/0.75 mm; feed 36 mm/s; rotation time 500 ms; increment 0.4 mm; 120-150 mAs and 120 kVp. A volume of 80 ml of contrast material was administered through an antecubital vein (rate 4 ml/s), followed by 40 ml of saline (rate 4 ml/s). Images were analysed on the workstation with different algorithms (axial image scrolling, multiplanar reconstructions, maximum intensity projection, volume rendering). Targeted central lumen-line reconstructions (curved reconstructions) were obtained along the celiac trunk (CeT) and superior mesenteric artery (SMA). Vessel occlusions and significant (>50%) stenosis were recorded., Results: Image generation and interpretation required 25 min. Stenosis and/or occlusions were detected in 29 (65%) cases on the CeT and in 32 (71%) on the SMA. Of those lesions (n=61), 44 (49%) were classified as not significant. In 16 (35%) cases, there was a simultaneous stenosis and/or occlusion of the CeT and SMA (confirmed by conventional angiography). In six (13%) cases, there were no lesions affecting the CeT, SMA or their branches (confirmed by clinical follow-up)., Conclusions: MSCT angiography can play a major role in the detection of stenosis of the abdominal arteries in patients with suspected CMI.

Purpose: The aim of our study was to assess the influence of heart rate on the selection of the optimal reconstruction window with 40-slice multidetector-row computed tomography (40-MDCT) coronary angiography., Materials and Methods: We studied 170 patients (114 men, age 60+/-11.3 years) with suspected or known coronary artery disease with 40-MDCT coronary angiography. Patients [mean heart rate (HR) 62.9+/-9.3 bpm, range 42-94 bpm] were clustered in two groups (group A: HR 65 bpm). Multiphase reconstruction data sets were obtained with a retrospective electrocardiogram (ECG)-gated 40-MDCT coronary angiography scan from 0% to 95% every 5% of the R-R interval. Two radiologists in consensus evaluated the best data sets for diagnostic purposes., Results: In group A, the optimal reconstruction windows were at 70% (55/110, 71/110 and 69/110 for the right coronary artery, left anterior descending and the left circumflex, respectively) and 75% (26/110, 28/110 and 28/110, respectively) of the R-R interval. In group B, a wide range of reconstruction windows were employed, both in the end-systolic phase at 40% (32/60, 18/60 and 17/60, for the right coronary artery, left anterior descending and circumflex, respectively) and diastolic phases at 70% (12/60, 22/60 and 19/60, respectively). Six scans were excluded due to severe respiratory artefacts., Conclusions: Optimal position of the image reconstruction window relative to the cardiac cycle is significantly influenced by the heart rate during scanning. Diastolic reconstruction phases often allowed an optimal assessment in group A. Reconstruction phases from 30% to 45% are advisable for higher heart rates.

Purpose: To review the current radiological methodologies and guidelines for staging and followup in oncology, and to give a perspective based on the available new technologies in oncologic radiology., Materials and Methods: The literature on cancer radiologic quantification in diagnostic phase and follow-up has been reviewed. The main concepts and guidelines (official and non-official) have been extracted taking into account the period of publication and the available technology. The current World Health Organization (WHO) and Response Evaluation Criteria In Solid Tumors (RECIST) guidelines have been critically evaluated on the basis of technical literature on quantitative radiology applied to oncology. Pitfalls of previous and current guidelines have been exploited on the basis of currently available techniques for quantification., Results: Errors due to operator, scanner, software, and measurement technique inconsistency are all together far more relevant than the recognized thresholds applied for detecting therapeutic response. For this reason the volumetric assessment of cancer disease should be introduced., Conclusion: Even though the technical constraints are still prominent in the clinical practice, the design of clinical trials should be planned taking into account these new volumetric quantitative techniques.

Objective: The objective of our study was to assess the accuracy of one of the most used scoring systems, the Bhalla scoring system, in the detection of lung impairment in patients with cystic fibrosis and in the prediction of cystic fibrosis progression., Materials and Methods: From the database of our center, 300 CT examinations performed between 1991 and 2001 were reviewed. Pulmonary function tests performed the same day as radiologic assessment were available. Of this group, 145 examinations were retrospectively included, referring to 87 patients with confirmed cystic fibrosis and a mean age (+/- SD) of 15.6 +/- 8.4 years (range, 9 months-38 years). Thirty patients underwent one CT examination, 56 underwent two examinations, and one patient underwent three examinations. The mean interval between two examinations was 36.5 months. The 145 examinations were independently reviewed by three radiologists who were blinded to the clinical and pulmonary function test results. The CT examinations were assessed using the scoring system proposed by Bhalla and colleagues., Results: CT assessed using the Bhalla scoring system is mildly correlated with functional pulmonary test results and has high interobserver reproducibility. The CT score significantly changed between scans obtained in a mean interval of 36.5 months, whereas functional pulmonary test results did not, suggesting that CT is more sensitive than function tests for detecting small changes. However, the variation in CT scores did not predict progression of functional pulmonary test results or progression of CT findings between scans., Conclusion: CT assessment based on the Bhalla scoring system is more sensitive than pulmonary function tests in detecting initial morphologic changes. However, we found no evidence of the predictive value of CT.

Purpose: To develop a voxel-based analysis of an R2* map of healthy human brain that is automatic, reproducible, and realizable in a single examination on a 3T MR imager. Such a tool could be useful to measure iron accumulation in neurodegenerative diseases., Materials and Methods: In all, 18 healthy subjects underwent MR imaging at a field strength of 3T: 1) six consecutive T2*-weighted gradient-echo volumes were acquired using a segmented echo-planar imaging sequence and 2) a conventional dual-echo turbo spin echo sequence was also applied to acquire T2-weighted images. Images were realigned and spatial correction was performed using a template brain dataset with SPM2. For each subject we performed a voxel-by-voxel nonlinear least-squares fitting of the data acquired at the six echo times to obtain a monoexponential signal decay curve. The reproducibility and sensitivity to age variation were assessed by voxel-based analysis., Results: The reproducibility tests in whole brain analysis showed little R2* variation. Furthermore, the statistical analysis, performed on each brain voxel, revealed a significant positive correlation between age and MR values located in regions where a slow and constant age-related iron deposition is known., Conclusion: Our method, combining data acquisition and data processing, demonstrates the feasibility of voxel-based analysis on an R2* map and affords a high degree of sensitivity and good reproducibility while maintaining high spatial resolution., ((c) 2007 Wiley-Liss, Inc.)

In this study, we defined an operator-independent protocol for reconstructing the anatomical connections originating from fMRI activations in order to demonstrate that results obtained with this protocol are affected by alterations of functional activations. Seven healthy volunteers and two patients who sustained traumatic brain injury underwent an fMRI with a finger tapping task and a DTI scan. Cortical fMRI activations were used directly as seed mask for tractography for the reconstruction of individual motor pathways. On patients we observed a different motor network if compared to healthy subjects. However, when the activations of healthy subjects were used as seed masks for the tractography in patients, we observed for the patients a pattern of connectivity more similar to what was observed for healthy subjects. At the same time, when the activations of patients were used for the tractography on healthy subjects, we obtained patterns of connectivity similar to those obtained for patients. These results show the potential of the integration of fMRI and tractography for clarifying the mechanisms of cortical plasticity in the recovery of motor functions.

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.

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.

With the increasing diffusion of 4-row,16-row and 64-row multislice computed tomography scanners, widespread coronary calcium scoring has become possible in Europe. This relatively easy-to-perform test has a high sensitivity and low specificity for the detection of significant coronary artery stenosis, and may have an important role in the risk stratification for future coronary artery events in selected groups of patients, such as those immediately at risk. This study reviews the techniques available for coronary calcium scoring (electron beam tomography and multislice computed tomography) with their respective protocols, as well as their advantages and disadvantages. The methods for interpreting the results, the potential indications and the clinical applications of the techniques are also described.

Three-dimensional reconstructions represent a visual-based tool for illustrating the basis of three-dimensional post-processing such as interpolation, ray-casting, segmentation, percentage classification, gradient calculation, shading and illumination. The knowledge of the optimal scanning and reconstruction parameters facilitates the use of three-dimensional reconstruction techniques in clinical practise. The aim of this article is to explain the principles of multidimensional image processing in a pictorial way and the advantages and limitations of the different possibilities of 3D visualisation.

Rationale and Objectives: to compare contrast material (CM) administration protocols in non-invasive coronary angiography (CA) using a 16-row multislice CT (16-MSCT)., Methods: 45 patients undergoing CA with 16-MSCT were divided into three CM protocols: group 1 (140 ml@4ml/s), group 2 (140 ml = 60 ml@5ml/s + 80 ml@3ml/s), and group 3 (100 ml@4ml/s). The attenuation at the origin of the coronary vessels was assessed. Three regions of interest were evaluated: 1) ascending aorta (ROI1); 2) descending aorta (ROI2); 3) pulmonary artery (ROI3). The resulting time-density curves generated the average attenuation and the slope of bolus geometry., Results: the attenuation at the origin of the coronary vessels, and the average attenuation of bolus geometry were not significantly different (p > 0.05). The slope of bolus geometry was in ROI1 and ROI2 significantly lower for group 2, in ROI3 significantly lower for group 3 (p < 0.05)., Conclusion: 100 ml of CM provide the same attenuation in 16-MSCT CA as mono- or multi-phasic 140 ml protocols.

Purpose: To assess the variability in attenuation of coronary plaques with multislice CT-angiography (MSCT-CA) in an ex-vivo model with varying convolution kernels., Materials and Methods: MSCT-CA (Sensation 16, Siemens) was performed in three ex-vivo left coronary arteries after instillation of contrast material solution (Iomeprol 400 mgI/ml, dilution: 1/80). The specimens were placed in oil to simulate epicardial fat. Scan parameters: slices 16/0.75 mm, rotation time 375 ms, feed/rotation 3.0 mm, mAs 500, slice thickness 1 mm, and FOV 50 mm. Datasets were reconstructed using 4 different kernels (B30f-smooth, B36f-medium smooth, B46f-medium, and B60f-sharp). Each scan was scored for the presence of plaques. Once a plaque was detected, the operator performed attenuation measurements (HU) in coronary lumen, oil, calcified and soft plaque tissue using the same settings in all datasets. The results were compared with T-test and correlated with Pearson's test., Results: Overall, 464 measurements were performed. Significant differences (p<0.05) were found for the mean attenuation of lumen (B30f/B36f, B30f/B60f, B36f/B46f, B36f/B60f, and B46f/B60f), oil (B30f/B36f, B30f/B46f, B30f/B60f, B36f/B46f, and B46f/B60f), calcium (all kernels), and plaque (B30f/B36f, B30f/B46f, B30f/B60f, and B46f/B60f) using 4 different kernels. The attenuation values (mean+/-SD) within the lumen (246+/-6, 215+/-13, 248+/-5, and 270+/-7), oil (-123+/-3, -127+/-1, -121+/-6, and -127+/-4), calcified plaque tissue (703+/-334, 739+/-364, 817+/-381, and 1181+/-503), and soft plaque tissue (134+/-56, 111+/-49, 120+/-56, and 102+/-41) showed high correlation (p<0.001) when attenuation of all structures were compared in different kernels., Conclusions: Use of sharper convolution kernels significantly increases the attenuation of the calcium within coronary plaques and reduces the attenuation of soft plaque tissue.

Purpose: To assess the effect of intravascular enhancement, heart rate, and calcium score on diagnostic accuracy in the detection of significant coronary artery stenosis using 16-row multislice computed tomography (MSCT)., Materials and Methods: One hundred patients (88 males; 59+/-11 years) with suspected coronary artery disease who had undergone conventional coronary angiography (CA) and MSCT-CA were retrospectively enrolled for the study. Patients underwent a MSCT-CA, with the following protocol: collimation 16x0.75 mm, gantry rotation time 420 ms, feed/rotation 2.8 mm, kV 120, mAs 400-500. The protocol for contrast material administration was 100 ml of Iodixanol 320 mgI/ml at 4 ml/s and the scan delay was defined with a bolus tracking technique. In all patients vascular enhancement was measured in the aortic root, and in the left and right coronary arteries. The average vascular enhancement was used to divide the population in two groups of 50 patients each, one with lower enhancement (Low), and one with higher enhancement (High). In the two groups diagnostic accuracy (per coronary segment) for the detection of significant stenosis (= or >50% lumen reduction) was evaluated in vessels = or >2 mm in diameter using quantitative CA as the reference standard. The differences in diagnostic accuracy were compared with a Chi-square test and a p<0.05 was considered significant., Results: Of the total 1116 segments (= or >2 mm lumen diameter), 173 presented significant stenosis. The sensitivity and specificity for the assessment of significant stenosis were 89.4% and 93.3% vs 94.3% and 97.4% in the presence of increasing intravascular enhancement, 92.8% and 96.7% vs 91.1% and 93.9% in the presence of increasing heart rate, and 89.7% and 97.6% vs 93.3% and 92,8% in the presence of an increasing calcium score., Conclusions: Increasing intravascular enhancement significantly improves diagnostic accuracy in MSCT-CA. A higher heart rate lowers the specificity in the detection of significant obstructing lesions of the coronary artery. An increasing calcium score determines a lower specificity and a higher sensitivity.

The aim of this article is to illustrate the main technical improvements in the last generation of 64-row CT scanners and the possible applications in coronary angiography. In particular, we describe the new physical components (X-ray tube-detectors system) and the general scan and reconstruction parameters. We then define the scan protocols for coronary angiography with the new generation of 64-row CT scanners to enable radiologists to perform a CT study on the basis of the diagnostic possibilities.

Purpose: To evaluate the diagnostic accuracy of multislice computed tomography coronary angiography (MSCT-CA) in the detection of in-stent restenosis., Materials and Methods: Forty-two patients (33 male, 9 female, mean age 58+/-8 years) previously subjected to percutaneous implantation of coronary stent with suspected in-stent restenosis, underwent a 16-row MSCT (Sensation 16, Siemens) examination. The average time between stent implantation and MSCT-CA was 7.4+/-5.3 months. The following scan parameters were used: collimation 16x0.75 mm, rotation time 0.42 s, feed 3.0 mm/rot., kV 120, mAs 500. After administration of iodinated contrast material (Iomeprol 400 mgI/ml, 100 ml at 4 ml/s) and bolus chaser (40 ml of saline at 4 ml/s) the scan was completed in <20 s. All segments with a stent were assessed by two observers in consensus and were graded according to the following scheme: patent stent, in-stent intimal hyperplasia (IIH) (lumen reduction <50%), in-stent restenosis (ISR) (=/>50%), in-stent occlusion (ISO) (100%). Consensus reading was compared with coronary angiography., Results: Forty-seven stents were assessed (16 in the right coronary artery; 4 in the left main; 22 in the left anterior descending; 5 in the circumflex). In 7 (17%) stents there was ISR (3) or ISO (4), and in 4 (10%) stents there was IIH. The sensitivity and negative predictive values for the detection of ISO were 80% and 98%, respectively, while for the detection of ISR+ISO they were 50% and 89%, respectively., Conclusions: Although the results are encouraging, the follow-up of stent patency with MSCT-CA does not show a diagnostic accuracy suitable for clinical implementation.

Purpose: To evaluate the pitfalls occurring during the virtual colonoscopy examination performed with a protocol designed for screening purposes., Materials and Methods: 40 patients underwent a spiral CT for virtual colonoscopic evaluation with the following parameters: collimation 3 mm, feed 6 mm.rot(-1), pitch 2 and increment 1 mm in supine position. Virtual colonography examination was carried out using a dedicated workstation equipped with a software which allows to generate 3D images and virtual endoscopic views. Colon distension, fluid and fecal material were assessed on a 3 point scale., Results: Distension score was 0.50. Left colon and cecum score was 0.32 while in the sigmoid and rectum the score was worse with 0.86. Fluid and fecal residues scores were 0.31 and 0.19 respectively. On almost half of the patients additional scans would be necessary. The main cause of additional scans is suboptimal intestinal preparation and colon distension., Conclusion: The use of virtual colonoscopy for screening purposes will be possible through the further technical development and with the optimisation of the protocols, particularly by the improvement of colon cleansing and distension.

Aim: To assess the influence of pre-set volume-rendering opacity curves (OC) on image quality and to identify which absolute parameters (density of aorta, hepatic parenchyma and portal vein) affect visualization of portal vascular structures (low-contrast structures)., Materials and Methods: Twenty-two patients underwent a dual-phase spiral CT with the following parameters: collimation 3 mm, pitch 2, increment 1 mm. Three scans were performed: one without contrast medium and the latter two after the injection of contrast material (conventionally identified as ''arterial'' and ''portal''). The images were sent to a workstation running on an NT platform equipped with post-processing software allowing three-dimensional (3D) reconstructions to generate volume-rendered images of the vascular supply to the liver. Correlation between the absolute values of aorta, liver and portal vein density, OC parameters, and image quality were assessed., Results: 3D images generated using pre-set OC obtained a much lower overall quality score than those produced with OC set by the operator. High contrast between the liver and the portal vein, for example during the portal vascular phase, allows wider windows, thus improving image quality. Conversely, the OC in the parenchymal phase scans must have a high gradient in order to better differentiate between the vascular structures and the surrounding hepatic parenchyma., Conclusions: Image features considered to be of interest by the operator cannot be simplified by the mean of pre-set OC. Due to their strong individual variability automatic 3D algorithms cannot be universally applied: they should be adapted to both image and patient characteristics.

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.

Objective: Volumetric analysis was compared with conventional unidimensional measurements for follow-up of rectosigmoid cancer before and after radiation therapy., Subjects and Methods: Fifteen patients with rectosigmoid cancer underwent helical CT before and after neoadjuvant radiation therapy. The helical CT examination was performed after colon distention with air and IV administration of an antiperistaltic drug. Two scans were obtained: one with the patient in the supine position and the other with the patient in the prone position after contrast medium injection. The maximal wall thickness and the volumetric analysis of the tumor were obtained through manual segmentation., Results: The mean of the differences between the volumetric analysis of the scans obtained before and after radiation therapy was 8.3 +/- 10.3 (SD) mL (-22.7%) (p <0.05). The mean of the differences between the maximal wall thickness of the pre- and post-radiation therapy scans was 3.4 +/- 2.6 mm (-19.1%) (p <0.05). A significant difference was observed between the variation of the maximal wall thickness and the variation of volumetric analysis in pre- and post-radiation therapy scans (p <0.05). The patients could be classified in different response categories depending on the measurement method and on the response criteria., Conclusion: Volumetric analysis of rectosigmoid cancer is feasible. A long-term study is needed to correlate volumetric assessment with patient outcome.

Purpose: To evaluate the diagnostic accuracy of 16-row multislice spiral computed tomography coronary angiography (16-MSCT-CA) for the non-invasive assessment of significant coronary artery stenosis., Materials and Methods: We enrolled 40 patients (36 male, aged 59+/-11 yrs) with suspected obstructive coronary artery disease and a heart rate <65 bpm during the scan. The 16-MSCT-CA (Sensation 16, Siemens, Forchheim, Germany) was performed with electrocardiographically-gated technique after the intravenous administration of 100 ml of iodinated contrast material followed by a saline bolus chaser. The scan parameters were: collimation 16 x 0.75 mm, rotation time 0.42 s, feed/rot. 3 mm (pitch 0.25), 120 kVp, 500 mAs. All coronary segments = or >2 mm in diameter were evaluated by two independent observers for the presence of significant coronary artery stenosis (= or >50%). Consensus reading was compared to quantitative coronary angiography., Results: The average heart rate was 55+/-6 bpm. Of the 428 segments of = or >2.0 mm diameter 92 were significantly diseased. Without exclusion of any branches (428), the sensitivity, specificity, positive, and negative predictive values to identify = or >50% obstructed segments were 95.7% (88/92), 95.8% (322/336), 86.3% (88/102), and 98.8% (322/326), respectively. No occluded left main, left anterior descending, circumflex or right coronary artery segments remained undetected., Conclusions: 16-MSCT-CA in a selected low-heart-rate patient population provides high diagnostic accuracy in the evaluation of significant coronary artery stenosis.

Most patients with traumatic aortic lesions of the thoracic aorta die at the accident site but 15% arrive at the hospital with vital signs. Digital subtraction angiography is considered the gold standard for the diagnosis of traumatic lesions of the thoracic aorta. Other non-invasive diagnostic techniques, such magnetic resonance and spiral computed tomography, proved to be reliable alternatives. Sometimes the diagnosis can be delayed by the relative lack of significant symptoms as well as the presence of unusual clinical findings. A case of post-traumatic intramural haematoma of the descending aorta revealed during a magnetic resonance of the spine is described. The final diagnosis was obtained with spiral computed tomography.

Purpose: To describe a teleradiology system accessible via a PC and a common web browser., Material and Methods: A dedicated system is connected to several radiological imagers (DR, US, CT, MR) with DICOM standard and TCP/IP protocol. The images are visualised in a common web browser on a remote PC by connecting to the dedicated web-site. Compressed images are visualised on a web page. Special toolbars allow specific operations to be performed on the images (brightness-contrast, zoom, distance measurement and ROI defining) and the communication with the radiological centre., Results: The graphic interface is user-friendly and does not require any special knowledge, except for basic PC and internet surfing. Image compression can be set to preserve image quality, and image transfer is fast., Conclusions: The system presented overcomes the limitations of conventional teleradiology systems since it requires no special network or dedicated software, allowing for visualisation of a radiological examination on a PC and a common web browser.

In the past few years, magnetic resonance imaging (MRI) has become increasingly relevant in the diagnosis of multiple sclerosis (MS). Yet, the specificity of MR is limited. Atypical forms of MS and other diseases of the central nervous system may show similar patterns in MR. We briefly discuss the MR findings of the main MS-like diseases. Correct differential diagnosis can be carried out by combining the MR findings with clinical and laboratory findings.

Purpose: To apply the retrospective ECG-gating to the 16-row MSCT scan of intrathoracic vessels., Materials and Methods: Fourty-eight patients underwent MSCT with a new 16-row scanner (Sensation 16-Siemens) for the study of the great intrathoracic vessels. In group 1 (33 patients) a retrospectively ECG-gated protocol was applied; in the control-group 2 (15 patients) a conventional MSCT protocol for thoracic imaging was applied. Images were scored regarding 1) the presence or absence of artefacts determined by breath-hold, beam hardening and mis-triggering; 2) the visualisation (optimal, mild and poor) of great intrathoracic vessels (aorta, pulmonary arteries and veins); 3) the visualisation (presence or absence) of proximal, mid and distal coronary arteries (left main, left anterior descending, circumflex, and right coronary artery)., Results: Ascending aorta showed motion artefacts in 3 (20%) cases in group 2 and none in group 1. In group 1, proximal LAD, CX, and RCA were assessable in 94%, 91%, and 91%, respectively. Left main coronary artery was assessable in 32 (97%) and 10 (67%) cases for group 1 and 2, respectively. In group 2, proximal segments of left anterior descending (LAD), circumflex (CX), and right coronary artery (RCA), were almost not assessable., Conclusions: The retrospectively ECG-gated 16-row MSCT provides more information regarding ascending aorta and coronary arteries.

Computed tomography (CT) and magnetic resonance (MR) imaging allow more accurate staging of the carcinoma of the tongue than the clinical examination alone. The complex anatomy and the tumour margins make the interpretation of CT and MR images challenging. The aim of this paper is to review the technique and semiotic criteria for CT and MR evaluation and staging of carcinoma of the tongue.

Computed Tomography (CT) with three-dimensional reconstructions was studied in cranio-facial deformities. The pre-operative and follow-up study of cranio-facial deformities can be performed with spiral CT. With this modality quantitative information can be provided in order to measure the entity of airway obstruction and the result of procedure affecting bone structures.

Purpose: To investigate the impact of saline bolus chaser in coronary angiography with a 16-row multislice CT (16-MSCT) scanner., Materials and Methods: 32 patients were divided in two groups for contrast material (cm) administration: group 1 (140 ml at 4 ml/s), and group 2 (100 ml at 4 ml/s followed by 40 ml of saline chaser at 4 ml/s). All patients underwent ECG-gated coronary angiography with a 16-MSCT scanner. The attenuation at the origin coronary vessels was assessed. Three regions of interest were drawn throughout the data-set: ascending aorta (ROI1); descending aorta (ROI2); pulmonary artery (ROI3). The attenuation in the superior vena cava was recorded (ROI4). The average attenuation and the slope were calculated in each ROI., Results: The average attenuation in the coronary vessels was not significantly different in the two groups. The attenuation value in the superior vena cava was significantly inferior in group 2., Conclusions: 16-row MSCT coronary angiography with bolus chaser allows optimal vessel enhancement with a lower dose of cm and a lower enhancement of the superior vena cava and the right heart.

Purpose: To compare two different techniques for the administration of the bolus of contrast material (cm) in coronary angiography with multislice CT (MSCT) scanner., Materials and Methods: Thirty consecutive patients were divided into two groups. In group 1 contrast material was administered with the monophasic protocol (140 ml of cm at 4 ml/s). In group 2 contrast material was administered with the biphasic protocol (70 ml of cm at 4 ml/s and 70 ml at 3 ml/s). The angiographic scan was performed in both groups with a 16-row MSCT scanner. Three regions of interest were drawn in each scan throughout the data-set in order to measure attenuation: 1) ascending aorta (ROI1); 2) descending aorta (ROI2); 3) pulmonary artery (ROI3). Attenuation was also assessed at the origin of the main coronary arteries., Results: No significant differences of the attenuation values were observed at the origin of the coronary arteries (p>0.05). The attenuation profile of the monophasic protocol showed higher and longer attenuation values than the biphasic protocol. CONCLUSIONS. The biphasic administration of contrast material does not supply significant advantages on the enhancement of the great vessels and the coronary arteries in 16-row MSCT coronary angiography.

Since its introduction, spiral computed tomography (CT) technology underwent a continuous and fast technical and clinical development. In particular, spatial and temporal resolutions were constantly increased during the last decade. The main breakthrough for clinical application was the introduction of multislice technology, first with 2-row and 4-row equipment and more recently with 16-row scanners. A high-resolution sub-millimeter CT dataset can be acquired easily, although with an increased x-ray exposure for the patient. The high speed of the scan requires up-to-date and careful protocol optimization. Scanner technology and geometry affect image formation procedure and imaging protocols should be adapted accordingly. The technical foundations of spiral CT imaging and the main scan and reconstruction parameters are described in this article. Updated protocols and clinical examples of the latest applications are also discussed.