Changes in magnetic resonance imaging disease measures over 3 years in mildly disabled patients with relapsing-remitting multiple sclerosis receiving interferon ß-1a in the COGnitive Impairment in MUltiple Sclerosis (COGIMUS) study.

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) ß-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 ß-1a, 44 µg sc tiw, predicted an absence of cognitive impairment at Year 3. CONCLUSION: Subcutaneous IFN ß-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.

3 Tesla is twice as sensitive as 1.5 Tesla magnetic resonance imaging in the assessment of diffuse axonal injury in traumatic brain injury patients.

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.

Volume and iron content in basal ganglia and thalamus.

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.

Characterization of white matter fiber bundles with T2* relaxometry and diffusion tensor imaging.

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.

Object naming and action-verb generation in Parkinson's disease: a fMRI study.

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.

Colouring rehabilitation with functional neuroimaging.

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.

Language-Related Brain Potentials in Patients With Disorders of Consciousness: A Follow-up Study to Detect "Covert" Language Disorders.

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.

Predictive value of chest CT in patients with cystic fibrosis: a single-center 10-year experience.

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.

Imaging for oncologic staging and follow-up: review of current methods and novel approaches.

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.

Intravenous contrast material administration in multislice computed tomography coronary angiography.

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.

Pitfalls and feasibility of a protocol of virtual colonography designed for the screening of colo-rectal pre-cancerous lesions.

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.

MR angiography of the carotid arteries: parameters affecting image quality.

RATIONALE AND OBJECTIVES: This study was performed to evaluate the relationship between dose levels of contrast medium and image quality in magnetic resonance (MR) angiography of the carotid arteries with fluoroscopically monitored, manually triggered, elliptically ordered image acquisitions. MATERIALS AND METHODS: Twenty-five patients with clinical indications for angiography of the carotid arteries were examined with MR at 1.5 T by using a fluoroscopically monitored, manually triggered, elliptically ordered pulse sequence with the administration of one of three different volumes of gadolinium-based contrast medium. The signal intensities of the vessel lumen and the surrounding tissues were measured in single partitions at the origin of the common carotid artery, the carotid bifurcation, and the intracranial internal carotid arteries. The contrast-to-noise ratio in these regions of interest also was measured. Maximum intensity projection image quality was appraised for blurring, artifacts, venous enhancement, background suppression, and contrast medium distribution. RESULTS: No artifacts or venous enhancement was observed. The position of the fluoroscopic section affected the distribution of contrast medium along the vessel, as evidenced by the difference between the contrast-to-noise ratio at the origin of the common carotid artery and the ratio at the carotid bifurcation and the intracranial internal carotid arteries (P < .01). The contrast medium dose administered was strongly correlated with image quality (r = 0.90). CONCLUSION: Contrast medium dose is related to image quality in MR angiography of the carotid arteries performed with elliptical ordering, fluoroscopic monitoring, and manual triggering.

Sixteen-row multislice computed tomography: basic concepts, protocols, and enhanced clinical applications.

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.

Post-traumatic descending aorta intramural haematoma fortuitously witnessed during a magnetic resonance examination of the spine.

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.

Effective clinical outcome of a mandibular distraction device using three-dimensional CT with volume rendering in Pierre-Robin sequence.

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.

White matter hyperintensities segmentation: a new semi-automated method.

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.

A multimodal MRI investigation of the subventricular zone in mild cognitive impairment and Alzheimer's disease patients.

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.