User interface of a teleradiology system for the MR assessment of multiple sclerosis.

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.

Infratentorial lesion volume correlates with sensory functional system in multiple sclerosis patients: a 3.0-Tesla MRI study.

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.

Cognitive impairment and its relation with disease measures in mildly disabled patients with relapsing-remitting multiple sclerosis: baseline results from the Cognitive Impairment in Multiple Sclerosis (COGIMUS) study.

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.

What insights have new imaging techniques given into aggressive forms of MS--different forms of MS or different from MS?

"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.

Noninvasive evaluation of the celiac trunk and superior mesenteric artery with multislice CT in patients with chronic mesenteric ischaemia.

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.

Influence of heart rate in the selection of the optimal reconstruction window in routine clinical multislice coronary angiography.

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.

Three-dimensional quantitative assessment of lung parenchyma in cystic fibrosis: preliminary results.

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.

Coronary artery anomalies: incidence, pathophysiology, clinical relevance and role of diagnostic imaging.

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.

Imaging nervous pathways with MR tractography.

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.

Non-invasive assessment of coronary artery stent patency with multislice CT: preliminary experience.

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.

Diagnostic accuracy of 16-row multislice CT angiography in the evaluation of coronary segments.

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.

Atypical multiple sclerosis: MRI findings and differential diagnosis.

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.

Non-invasive angiography of the coronary arteries with multislice computed tomography: state of the art and future prospects.

Until now conventional angiography has represented the only technique for assessing the coronary arteries. During the last decade, attempts have been made to validate a non-invasive technique for the study of coronary arteries. In particular, Electron-beam Tomography and Magnetic Resonance Imaging have been used for this purpose, even though they have not become clinical tools. More recently, spiral computed tomography (CT) technology, improved by the use of multiple slices and 500ms gantry rotation times, has shown a good potential without entering routine clinical practice. The introduction of multislice technology with 16 rows and rotation times below 500ms has yielded such good results in detecting significant (>50%) coronary artery stenosis that it has been proposed as a clinical tool. This paper describes the examination technique and the results achieved in CT angiography of the coronary arteries.

Improving the results of virtual colonoscopy: what the future will bring.

Several studies show the possibility of using virtual colonoscopy in radiologic routine. To understand what its future holds, a deep insight into the techniques and pitfalls is mandatory. Currently, patient preparation and insufflation methods have to be improved because they represent the main source of pitfalls. Acquisition techniques currently provide only morphologic information, which is inadequate in the case of flat lesions. Functional information is needed but not yet available. Although the development of postprocessing techniques during the past few years has been rapid, virtual colonoscopy cannot yet be proposed as a screening technique. State-of-the-art technology, however, allows us to imagine that in the near future it will become a tool suitable for routine application.

From maximum intensity projection to volume rendering.

Three-dimensional medical images can be generated with a variety of computer algorithms from computed tomography and magnetic resonance data sets. The most commonly used techniques are maximum intensity projection (MIP) and shaded surface display (SSD). Recently, volume rendering (VR) has become available on dedicated workstations, providing the possibility of interaction with data sets. All 3D rendering techniques represent a volume of data in 1 or more 2-dimensional (2D) planes, conveying the spatial relationships inherent in the data with the use of visual depth cues. Techniques and artefacts regarding MIP, SSD, and VR are described here, along with several models of clinical application.

Three-dimensional contrastless varicography by spiral computed tomography.

OBJECTIVE: to report and discuss preliminary results obtained in varicose limbs by means of a volume rendering (VR)-computed tomography (CT) technique without contrast medium injection. MATERIALS AND METHODS: VR-CT and duplex sonography (US) were performed to visualise the superficial veins of the lower extremity in eight healthy and 12 varicose limbs. RESULTS: VR-CT clearly demonstrated the 3D arrangement of the superficial veins and visualised small sized veins which were not visible at US examination. CONCLUSIONS: VR-CT is not suitable for routine evaluation of varicose limbs. VR-CT 3D reconstructions may be useful in the evaluation of atypical varicosis. Further studies are needed to define the role of VR-CT in deep venous disease.

Visualización tridimensional del árbol venoso superficial por scanner helicoidal / Tridimensional view of the superficial venous tree by helicoidal scanner

La técnica de adquisición volumétrica, asociada a la CT (Spiral Computarized Tomography or helicoidal scanner) se emplea desde hace algún tiempo para la reconstrucción tridimensional de los órganos. Los autores han querido experimentar la posibilidad de emplear clínicamente este método para visualizar el árbol venoso superficial de los miembros inferiores, y explorar de esta forma las posibilidades dadas por la técnica de "Volume Rendering"

Visualización tridimensional del árbol venoso superficial por scanner helicoidal / Tridimensional view of the superficial venous tree by helicoidal scanner

La técnica de adquisición volumétrica, asociada a la CT (Spiral Computarized Tomography or helicoidal scanner) se emplea desde hace algún tiempo para la reconstrucción tridimensional de los órganos. Los autores han querido experimentar la posibilidad de emplear clínicamente este método para visualizar el árbol venoso superficial de los miembros inferiores, y explorar de esta forma las posibilidades dadas por la técnica de "Volume Rendering"