Magnetic resonance image

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An observational study of variations in the appearance of the alar ligament on magnetic resonance imaging (MRI) and the normal range of lateral flexion and rotation of the atlas was performed to validate some of the premises underlying the use of MRI for the detection of injuries to the alar ligament. Fifteen healthy volunteers were included. Three sets of coronal proton-density images, and axial T2-weighted images of the craniovertebral junction, were obtained at 0.5 T with the neck in neutral position and laterally flexed (coronal proton density) or rotated (axial T2). Five of the subjects also underwent imaging at 1.5 T. The scans were independently examined twice by two radiologists. The presence of alar ligaments was recorded and a three-point scale used to grade the extent of hyperintensity exhibited by the structures: the ligament were graded as 2 and 3 if, respectively, less or more of its cross-section was hyperintense, whereas grade 1 represented a hypointense ligament. The effect of lateral flexion on image quality was assessed. Concordance analysis of the data were performed before and after dichotomising the data on grading. The atlanto-axial angle and rotation of the atlas were measured. The magnitude of movement to right was normalised to that to the left to give, respectively, the flexion index and the rotation index. The alar ligaments were most reliably seen on coronal proton-density scans, with a Maxwell's RE of 0.96 as compared with 0.46 for sagittal images. Flexion of the neck improved definition of the ligaments in only rare instances. Inter-observer disagreement was marked with respect to grading of the ligament on both coronal [composite proportion of agreement (p 0 )=0.44; 95% confidence intervals: 0.26, 0.64)] and sagittal scans [p 0 =0.40 (0.19, 0.63)]. Dichotomising the data did not appreciably improve reliability [Maxwell's RE: )0.11 (coronal scans), )0.20 (sagittal scans)]: for ligaments which demonstrated hypertensive areas (grades 2 and 3) there was complete lack of agreement for both coronal [p 2 =0 (0, 0.25)] and sagittal scans [p2=0 (0-0.30)]. A large response bias was found in the reports of both readers albeit in opposite directions. There was poor concordance between scans obtained at different field strengths [RE (coronal images)=0.25; RE (sagittal images)=0.14). Mean flexion index and mean rotation index were 1.00 (SD 0.03) and 1.01 (SD 0.06), respectively. The MR imaging may not be the investigation of choice for the investigation of subtle injuries to the alar ligament. Whether it can be substituted by kinematic assessment of the occipito-atlanto-axial complex with MRI warrants investigation.

-Thoracic Spinal Cord Compression by Ligamentum Flavum Ossifications. Ossification of the ligamentum flavum is common in Japan but rare in Western countries. Myelopathy of variable severity is a possible complication. Extension of the lesions over several levels at the thoracic spine is exceedingly rare. We report a new case in a 50-year-old man who had slowly progressive spinal cord compression with a sensory level at the navel. Computed tomography (CT) and magnetic resonance imaging (MRI) of the thoracic spine showed calcium-density masses that were in contact with the neural arches and bulged into the spinal canal at T5/T6, T7/T8, T9/T10, and T10/T11. Laboratory test findings were unremarkable. Surgical decompression by laminectomy and foraminotomy was followed by a favorable outcome. Histology showed extensive areas of bone metaplasia associated with calcific deposits. The diagnosis, treatment, and possible etiologies of this rare condition are discussed based on a literature review.

Objectives: 1) to correlate thigh muscle volume measured by magnetic resonance image (MRI) with anthropometric measurements and physical function in elderly subjects; 2) to predict MRI-measured thigh muscle volume using anthropometric measurements and physical functional status in elderly subjects. Design: Crosssectional, nonrandomized study. Setting: Outpatient clinic in Taiwan. Participants: Sixty-nine elderly subjects (33 men and 36 women) aged 65 and older. Measurments: The anthropometric data (including body height, body weight, waist size, and thigh circumference), physical activity and function (including grip strength, bilateral quadriceps muscle power, the up and go test, chair rise, and five meters walk time) and bioelectrical impedance analysis data (including total body fat mass, fat-free mass, and predictive muscle size) were measured. MRImeasured muscle volume of both thighs was used as the reference standard. Results: The MRI-measured thigh volume was positively correlated with all anthropometric data, quadriceps muscle power and the up and go test as well as fat-free mass and predictive muscle mass, whereas it was negatively associated with age and walk time. In predicting thigh muscle volume, the variables of age, gender, body weight, and thigh circumference were significant predictors in the linear regression model: Muscle volume(cm 3) =4226.3-42.5×Age(year)-955.7× gender(male=1, female=2)+45.9×body weight(kg) +60.0×thighcircumference (cm) (r 2 = 0.745, P < 0.001; Standard Error of the Estimate = 581.6cm 3). Conclusion: The current work provides evidence of a strong relationship between thigh muscle volume and physical function in the elderly. We also developed a prediction equation model using anthropometric measurements. This model is a simple and noninvasive method for everyday clinical practice and follow-up.

To assess the effectiveness of the current UK clinical practice in reducing hepatic fat (IHCL). Whole body MRI and (1)H MRS were obtained, before and after 6 mo nutritional counselling, from liver, soleus and tibialis muscles in 10 subjects with non-alcoholic fatty liver disease (NAFLD). A 500 Kcal-restricted diet resulted in an average weight loss of 4% (-3.4 kg,) accompanied by significant reductions in most adipose tissue (AT) depots, including subcutaneous (-9.9%), abdominal subcutaneous (-10.2%) and intra-abdominal-AT (-11.4%). Intramyocellular lipids (IMCL) were significantly reduced in the tibialis muscle (-28.2%). Decreases in both IHCL (-39.9%) and soleus IMCL (-12.2%) content were also observed, although these were not significant. Several individuals showed dramatic decreases in IHCL, while others paradoxically showed increases in IHCL content. Changes in body composition were accompanied by improvements in certain liver function tests: serum aspartate aminotransferase (A...

DTI-015 (BCNU dissolved in ethanol) utilizes solvent facilitated perfusion (SFP) for intratumoral drug delivery. A phase II clinical trial of DTI-015 and fractionated external beam radiotherapy on newly diagnosed, malignant gliomas investigated early changes in tumour physiology and metabolism, clinical outcome and safety. Pre-and post DTI-015 injection neuro-imaging included computed tomography (CT) cerebral blood flow and volume, glucose and thallium single photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI). Clinical status was determined before and after DTI-015, prior to radiotherapy and 3 monthly thereafter until progression (defined by Macdonald criteria). Primary endpoint was radiographic response. Secondary endpoints were progression free (PFS) and overall survival (OS). Twelve patients were enrolled; eight glioblastoma multiforme (GBM), four anaplastic astrocytoma (AA). Three days after DTI-015 injection, mean tumour blood flow (Paired t-test; P \ 0.001) and blood volume (Paired t-test; P = 0.001) were significantly reduced. There was a significant decrease in glucose utilization (Paired t-test; P \ 0.001) and thallium uptake (Paired ttest; P \ 0.001) at 6 days. Tumour blood volume had a sustained reduction (Paired t-test; P = 0.001) at 26 days after DTI-015. There were two serious adverse events. Two patients with AA achieved a partial response. Median PFS was 39 weeks for AA and 27 weeks for GBM; median OS for GBM was 47 weeks and 132 weeks for AA. The imaging data forms a biological basis for understanding the effects of high dose BCNU delivered intratumorally by SFP, and suggests early effects on tumour vasculature and metabolism.

Magnetic resonance imaging (MRI) and other techniques are being used to investigate moisture transport in textiles. MRI revealed that moisture distribution in carpet is significantly influenced by the vacuum extraction procedure. Industrially relevant through-flow drying of carpet has been simulated on a laboratory through-flow dryer (LTFD) as well as inside a MRI scanner. The effects of the moisture distribution and

Objects Among patients with medulloblastoma, an unrare aggressive central nervous system (CNS) tumor found mostly in the posterior fossa, drop metastasis from primary location to anatomically lower sites including whole spinal cord is known as a potential way for tumor to spread. There were already lots of extensive discussions regarding diagnosis and treatment for such common neurologic complication in systemic cancer; however, fewer were found about medulloblastoma. This study aimed to reex-amine the possible known prognostic factors, especially drop metastasis, and defined the influence of them. Materials and methods We retrospectively review a series of 36 patients who suffered from posterior fossa medulloblastoma and found leptomeningeal metastasis in 12 of them. Incidence, diagnosis, prognostic factors, and treatments for this common complication are discussed. The magnetic resonance images (MRI) of these patients were reviewed. The time sequence between primary surgical procedure and development of MRI evidences of drop metastasis was used for subgrouping. Log-rank test was used for survival analysis. Conclusions By survival analysis, patients with late drop metastasis, defined as new radiologic evidence of leptomeningeal involvement after primary CNS procedures, were found to have significant survival difference to those with early metastasis defined as drop metastasis found at the time of diagnosis (log-rank test, p=0.0047). Further stratification of patients within this group may help in evaluation of prognosis and development of different treatment strategies.

Objectives-It has been shown that atrophy of medial temporal lobe structures such as the hippocampus and entorhinal cortex shown on MRI may distinguish patients with Alzheimer's disease from healthy controls. However, the diagnostic value of visual inspection and volumetry of medial temporal lobe atrophy (MTA) on MRI in a clinical setting is insuYciently known. Methods-Medial temporal lobe atrophy in 143 patients was visually rated from hard copies, using a 0-4 rating scale and a comparison was made with the volumes (cm 3 ) of the medial temporal lobe as estimated with volumetry, using a stereological method. All patients were recruited in an unselected way in a clinical setting in the centre for memory impairments at the Huddinge University Hospital. Patients with Alzheimer's disease (n=41), patients with other dementias (vascular dementia, frontotemporal dementia, and unspecified dementia; n=36) as well as non-demented subjects (n=66) were included. Medial temporal atrophy and volumetry were evaluated as a diagnostic tool by performing logistic regression analysis including age, sex, and mini mental state examination (MMSE) score and calculating the sensitivity and specificity and percentage correct classification.

A procedure to fuse the information of short-axis cine and late enhanced magnetic resonance images is presented. First a coherent 3D reconstruction of the images is obtained by objectbased interpolation of the information of contiguous slices in stacked short-axis cine acquisitions and by the correction of slice misalignments with the aid of a set of reference longaxis slices. Then, late enhanced stacked images are also interpolated and aligned with the anatomical information. Thus, the complementary information provided by both modalities is combined in a common frame of reference and in a nearly isotropic grid, which is not possible with existing fusion procedures. Numerical improvement is established by comparing the distances between unaligned and aligned manual segmentations of the myocardium in both modalities. Finally, a set of snapshots illustrate the improvement in the information overlap and the ability to reconstruct the gradient in the long-axis.

A new, molybdenum core, 125 I interstitial brachytherapy seed is marketed by Bebig GmbH (IsoSeed s I25.S17) and our group has performed its Dosimetric characterization using Monte Carlo (MC) simulation and Thermoluminescence dosimetry (TLD) as recommended by the AAPM TG-43U1 prior to the clinical implementation of new low-energy seeds. This work presents the results of a supplementary experimental dosimetry study performed using PABIG polymer gel and Magnetic Resonance Imaging (MRI). One new I25.S17 seed and a commercially available, gold core, Bebig IsoSeed s I25.S06 125 I seed were positioned at two different locations in a vial filled with water equivalent, PABIG-polymer gel. The gel with the sources in place was MR scanned in 3D at various time intervals after seed placement using a time efficient, 3D, dual echo Turbo Spin Echo pulse sequence. The consensus dosimetry parameters published in the TG-43U1 for the I25.S06 seed were used to derive the gel response calibration curve for each scanning session. The calibration data were then used to provide dosimetry results for the new I25.S17 seed. Experimental results for the new seed in the form of dose distributions as well as dosimetric quantities in the prevalent TG-43 dosimetric formalism were found to be in close agreement with corresponding MC and TLD results. This finding suggests that the polymer gel-MRI method could at least play a supplementary role to TLD dosimetry in the dose characterization of low energy/low dose rate brachytherapy sources, especially in view of its potential for measurements with a fine spatial resolution down to short distances which are inhibitory to conventional experimental techniques.

The aim of this study was to assess the feasibility of diffusion tensor imaging (DTI) of the prostate and to determine normative fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of healthy prostate with a 3-Tesla magnetic resonance imaging (MRI) system. Thirty volunteers with a mean age of 28 (25–35) years were scanned with a 3-Tesla MRI (Intera Achieva; Philips, The Netherlands) system using a six-channel phased array coil. Initially, T2-weighted turbo spin-echo (TSE) axial images of the prostate were obtained. In two subjects, a millimetric hypointense signal change was detected in the peripheral zones on T2-weighted TSE images. These two subjects were excluded from the study. DTI with single-shot echo-planar imaging (ssEPI) was performed in the remaining 28 subjects. ADC and FA values were measured using the manufacturer supplied software by positioning 9-pixel ROIs on each zone. Differences between parameters of the central and peripheral zones were assessed. Mean ADC value of the central (1.220 ± 0.271 × 10−3 mm2/s) was found to be significantly lower when compared with the peripheral gland (1.610 ± 0.347 × 10−3 mm2/s) (P < 0.01). Mean FA of the central gland was significantly higher (0.26), compared with the peripheral gland (0.16) (P < 0.01). This study shows the feasibility of prostate DTI with a 3-Tesla MR system and the normative FA and ADC values of peripheral and central zones of the normal prostate. The results are compatible with the microstructural organization of the gland.

Functional imaging in humans and anatomical data in monkeys have implicated the insula as a multimodal sensory integrative brain region. The topography of insular connections is organized by its cytoarchitectonic regions. Previous attempts to measure the insula have utilized either indirect or automated methods. This study was designed to develop a reliable method for obtaining volumetric magnetic resonance imaging (MRI) measurements of the human insular cortex, and to validate that method by examining the anatomy of insular cortex in adults with Williams syndrome (WS) and healthy age-matched controls. Statistical reliability was obtained among three raters for this method, supporting its reproducibility not only across raters, but within different software packages. The procedure described here utilizes native-space morphometry as well as a method for dividing the insula into connectivity-based sub-regions estimated from cytoarchitectonics. Reliability was calculated in both ANALYZE (n=3) and BrainImageJava (N=10) where brain scans were measured once in each hemisphere by each rater. This highly reliable method revealed total, anterior, and posterior insular volume reduction bilaterally (all p’s < .002) in WS, after accounting for reduced total brain volumes in these participants. Although speculative, the reduced insular volumes in WS may represent a neural risk for the development of hyperaffiliative social behavior with increased specific phobias, and implicate the insula as a critical limbic integrative region. Native-space quantification of the insula may be valuable in the study of neurodevelopmental or neuropsychiatric disorders related to anxiety and social behavior.

Animal studies have shown that stress is associated with damage to the hippocampus, inhibition of neurogenesis, and deficits in hippocampal-based memory dysfunction. Studies in patients with posttraumatic stress disorder (PTSD) found deficits in hippocampal-based declarative verbal memory and smaller hippocampal volume, as measured with magnetic resonance imaging (MRI). Recent preclinical evidence has shown that selective serotonin reuptake inhibitors promote neurogenesis and reverse the effects of stress on hippocampal atrophy. This study assessed the effects of long-term treatment with paroxetine on hippocampal volume and declarative memory performance in PTSD. Declarative memory was assessed with the Wechsler Memory Scale-Revised and Selective Reminding Test before and after 9-12 months of treatment with paroxetine in PTSD. Hippocampal volume was measured with MRI. Of the 28 patients who started the protocol, 23 completed the full course of treatment and neuropsychological testin...

We found 42 of 7 4 patients (57%) with isolated monosymptomatic optic neuritis to have 1 to 20 brain lesions, by magnetic resonance imaging (MRI). All of the brain lesions were clinically silent and had characteristics consistent with multiple sclerosis (MS). None of the patients had ever experienced neurologic symptoms prior to the episode of optic neuritis. During 5.6 years of follow-up, 21 patients (28%) developed definite MS on clinical grounds. Sixteen of the 21 converting patients (76%) had abnormal MRIs; the other 5 (24%) had MRIs that were normal initially (when they had optic neuritis only) and when repeated after they had developed clinical MS in 4 of the 5. Of the 53 patients who have not developed clinically definite MS, 26 (49%) have abnormal MRIs and 27 (51%) have normal MRIs. The finding of an abnormal MRI at the time of optic neuritis was significantly related to the subsequent development of MS on clinical grounds, but interpretation of the strength of that relationship must be tempered by the fact that some of the converting patients had normal MFUs and approximately half of the patients who did not develop clinical MS had abnormal MRIs.

Objective The objective of this study is to describe the results of arthroscopic debridement for talar lesions in a population of soccer players. Patients Patients were sixteen soccer players with osteochondral talar lesions, treated surgically between 1999 and 2004. Interventions All patients were diagnosed clinically. Complementary imaging studies included X-ray, scintigraphy, and magnetic resonance imaging. All patients underwent arthroscopic debridement. Main outcome measurements At 3.56 years of follow up, patient status was assessed using a visual analog scale (VAS) and the Ogilvie-Harris scale. The mean time to return to sports at the same level as that before the start of symptoms was evaluated. Results The Ogilvie-Harris score showed 81.75% excellent results and 18.25% good results. The VAS score was 0.26 (0-2.2). Among the total, 93.75% of patients resumed sports activities at the same level as that before surgery. Conclusions Arthroscopic debridement of talar osteochondral lesions in soccer players provides excellent results. We consider this option the treatment of choice in this population.

Stress fractures are fatigue injuries of bone usually caused by changes in training regimen in the population of military recruits and both professional and recreational athletes. Raised levels of sporting activity in today's population and refined imaging technologies have caused a rise in reported incidence of stress fractures in the past decades, now making up more than 10% of cases in a typical sports medicine practice.

The accumulation of high levels of low-molecular-weight solutes (polyhydric alcohols, saccharides) provides cryoprotection to freeze-tolerant animals by minimizing, via colligative effects, the percentage of body water converted to extracellular ice and the extent of cell volume reduction. Many freeze-tolerant insects accumulate high levels of polyols during autumn cold hardening, whereas freeze-tolerant frogs respond to ice formation in peripheral tissues by synthesizing large amounts of glucose in the liver and rapidly distributing the sugar throughout the body. Seasonal patterns of enzymatic change occur in cold-hardy insects; activities associated with cryoprotectant synthesis rise in the fall, whereas enzymes associated with polyol degradation dominate in the spring. Enzyme profiles also revealed the route of glycerol degradation via polyol dehydrogenase and the novel enzyme, glyceraldehyde kinase. Proton magnetic resonance imaging of freezing and thawing in whole frogs showed a new adaptive effect of the very high glucose levels in core organs; during thawing, organs such as liver and heart melted first, allowing recovery of their vital functions to begin while the rest of the frog thawed. New studies have examined signal transduction in the stimulation of glucose production by wood frog liver, revealing the key role of β-adrenergic receptors and cAMP-mediated activation of glycogenolysis for cryoprotectant synthesis. The seasonal elevation of plasma membrane glucose transporters was also shown to be key to cryoprotectant distribution during freezing. Other new work has shown that frog freeze tolerance probably grew out of preexisting mechanisms of amphibian dehydration tolerance and that both freeze-tolerant and -intolerant frogs show a hyperglycemic response to desiccation at 5°C. comp biochem physiol 117A;3: 319-326, 1997. © 1997 proline is typically one of the major intracellular free amino tawa, Canada K1S 5B5. Tel. (613) 520-3678; Fax (613) 520-4389; e-mail acids in euryhaline marine invertebrates and one whose [email protected].

Stroke is defined as an abnormality in brain function resulting from disruption of cerebral circulation. It is the third leading cause of death in the United States and the primary cause of long-term disability. The economic burden of stroke will only increase as the population ages, making prevention and treatment of stroke one of the most important public health issues

Diabetic muscle infarction (DMI) is a rare, long-term complication of poorly controlled diabetes (typically of type I). DMI was first described in 1965 and more than 100 cases have been reported thereafter in the English literature. Usually, there is a coexistence with concomitant nephropathy, neuropathy, and retinopathy. The etiology remains uncertain, but appears to be attributable to diabetic microangiopathy and hypercoagulability and is believed that hypoxia-reperfusion injury is involved. DMI presents with sudden onset of pain associated with a tender mass in the thigh in most instances. The diagnosis is based on magnetic resonance imaging, which is not specific but highly indicative. Treatment is conservative with relapses occurring in 50% of the patients, but not necessarily in the same muscle group. We describe a case of DMI that occurred 4 months after simultaneous kidney and pancreas transplantation in one patient with type I diabetes mellitus and end-stage renal disease.

The optimal diagnostic evaluation for spontaneous intracerebral hemorrhage (ICH) remains controversial. In this retrospective study, we assessed the utility of early magnetic resonance imaging (MRI) in ICH diagnosis and management. Eighty-nine (72%) of 123 patients with spontaneous ICH underwent a brain CT and MRI within 30 days of ICH onset. Seventy patients with a mean age of 62 ± 15 years were included. A stroke neurologist and a general neurologist, each blinded to the final diagnosis, independently reviewed the admission data and the initial head CT and then assigned a presumed ICH cause under 1 of 9 categories. ICH cause was potentially modified after subsequent MRI review. The final &#39;gold standard&#39; ICH etiology was determined after review of the complete medical record by an independent investigator. Change in diagnostic category and confidence and the potential impact on patient management were systematically recorded. Mean time to MRI was 3 ± 5 days. Final ICH diagn...

Tuberculosis [TB] of the appendicular skeleton is an uncommon infection caused by the tuberculous bacilli and constitutes only 1-3% of all tuberculosis infections. MR imaging features of tuberculous arthritis include bone marrow oedema, cortical erosions, synovitis, joint effusion, tenosynovitis, soft tissue collections, and myositis. These imaging features are at times non-specific, but in the correct clinical context help in diagnosis of tuberculosis. We present the various pathological manifestations of TB arthritis involving the different joints of appendicular skeleton and discuss their MR imaging appearances.

Intracranial neurenteric cysts are rare congenital lesions that typically occur in the posterior fossa. We report a case of a 70-year-old gentleman presenting with gait disturbance, found to have a neurenteric cyst primarily arising from and expanding the sella turcica. A review of the literature revealed 27 reports of supratentorial neurenteric cysts. Clinical presentation, radiological characteristics, treatment, prognosis and embryological origin are discussed. Intracranial neurenteric cysts should be included in the differential with any well-demarcated cystic lesion without enhancement on magnetic resonance imaging (MRI). Complete surgical excision is the treatment of choice, with good prognosis.

In a chamber of the heart, large-scale vortices are shown to exist as the result of the dynamic blood flow and unique morphological changes of the chamber wall. As the cardiovascular flow varies over a cardiac cycle, there is a need for a robust quantification method to analyze its vorticity and circulation. We attempt to measure vortex characteristics by means of two-dimensional vorticity maps and vortex circulation. First, we develop vortex component analysis by segmenting the vortices using an data clustering algorithm before histograms of their vorticity distribution are generated. The next stage is to generate the statistics of the vorticity maps for each phase of the cardiac cycle to allow analysis of the flow. This is followed by evaluating the circulation of each segmented vortex. The proposed approach is dedicated to examining vortices within the human heart chamber. The vorticity field can indicate the strength and number of large-scale vortices in the chamber. We provide the results of the flow analysis after vorticity map segmentation and the statistical properties that characterize the vorticity components. The success of the cardiac measurement and analysis is illustrated by a case study of the right atrium. Our investigation shows that it is possible to utilize a data clustering algorithm to segment vortices after vorticity mapping, and that the vorticity and circulation analysis of a chamber vorticity can provide new insights into the blood flow within the cardiovascular structure.

Nanoparticle-based photonic explorers have been developed for intracellular sensing and photodynamic therapy (PDT). The design employs nanoparticles made of various matrices as multifunctional nanoplatforms, loading active components by encapsulation or covalent attachment. The nanoplatform for biosensing has been successfully applied to intracellular measurements of important ionic and molecular species. The nanoplatform for PDT has shown high therapeutic efficacy in a rat 9L gliosarcoma model. Specifically, a multifunctional nanoplatform that encompasses magnetic resonance imaging (MRI) and PDT agents inside, as well as targeting ligands on the surface, has been developed and applied in vivo, resulting in much improved MRI contrast enhancement and PDT efficacy.

The normal anatomy and many pathologies of the pediatric genitourinary system can be assessed with different imaging modalities. Most of them are based on the use of ionizing radiation and/or invasive techniques. The contribution of magnetic resonance imaging in this regard has opened new ways of approaching pathological conditions in this patient group. The addition of the newly developed rapid techniques has enhanced the superiority of MRI, and both morphological and functional evaluation of the genitourinary system can be achieved. There are different factors on which rely the optimization and the efficiency of magnetic resonance urography (MRU). Of importance is adequate patient immobilization and the use of optimal imaging sequences. The rapid technical development, including the advent of the post-processing respiratory navigator, allows acquisition of high-quality images independent of the patient's respiratory rate. In the future, it is expected that MRU, due to its non-use of ionizing radiation, will become the most important tool in the diagnostic work-up of genitourinary pathologies in infants and small children.

We propose a new hierarchical approach to resolution scalable lossless and near-lossless (NLS) compression. It combines the adaptability of DPCM schemes with new hierarchical oriented predictors to provide resolution scalability with better compression performances than the usual hierarchical interpolation predictor or the wavelet transform. Because the proposed hierarchical oriented prediction (HOP) is not really efficient on smooth images, we also

A three-layered backpropagation neural network was developed to differentiate malignant from benign brain tumors in a group of patients with astrocytic gliomas. The MRI findings of 43 patients were reviewed before biopsy by three neuroradiologists independently. This provided a database made up of 129 patients' records each of which comprised I3 parameters derived from pre-and post-contrast MR images. The network's generalizing ability was then tested to predict the outcome of biopsy in 36 new cases and its performance compared to that of radiologist using ROC analysis. The output of the network with and without radiologists' impression yielded a better diagnostic performance with relative ROC areas of 0.94 and 0.9 1. respectively, compared to 0.84 obtained by radiologist. These results demonstrate that the neural network can effectively differentiate malignant from benign brain tumors.

Evaluation of three directional three-dimensional velocity-encoded MRI (3D VE-MRI) with retrospective valve tracking to assess forward and backward flow over the pulmonary valve (PV) and tricuspid valve (TV), and to assess diastolic function in corrected Tetralogy of Fallot (cToF) patients.

Background: Solid plastic replicas of anatomical structures obtained by stereolithography from computed tomographic images and magnetic resonance imaging are being used as complementary tools for diagnostic purposes and therapy planning for diverse pathologies. Case Descriptions: Case 1-The spine mold of a 62-year-old man with neurologic compromise secondary to degenerative cervical disease was used to study the pathologic features of his spine and to plan and simulate the approach to remove osteophytes before surgery. Also, by examining the replica of his spine, the unconvinced patient was able to understand the nature of his pathology and realize that his neurologic symptoms would disappear only through surgery, as they did. Case 2-A 27-year-old woman had uncontrolled back and leg pain possibly related to anxiety and depression. She had undergone one unsuccessful lumbo-sacral surgery and was now obsessed with the thought that her second surgery, performed by us, likewise had failed, even though her magnetic resonance images proved otherwise. It was not until she held a replica of her repaired spine in her hands that she was able to understand that her pain was unfounded. Once she was able to relax, her chronic pain and anxiety disappeared within a month, using the same antidepressive treatment that formerly had been ineffective. Conclusions: Spine replicas are useful devices for diagnosis, planning, and simulating surgery, and they enable patients to understand the nature of their pathologies and the surgical procedures at hand.

The aging population in developed countries has shifted considerable research attention to diseases related to age. Because age is one of the highest risk factors for neurodegenerative diseases, the need for automated brain image analysis has significantly increased. Magnetic resonance imaging (MRI) is a commonly used modality to image brain. MRI provides high tissue contrast; hence, the existing brain image analysis methods have often preferred the intensity information to others, such as texture. Recently, an easy-to- compute texture descriptor, local binary pattern (LBP), has shown promise in various applications outside the medical field. In this paper, after extensive experiments, we show that rotation-invariant LBP is invariant to some common MRI artifacts that makes it possible to use it in various high-level brain MR image analysis applications.

Aims/hypothesis: Preferential visceral adipose tissue (VAT) accumulation has been clearly associated with insulin resistance. In contrast, the impact of visceral obesity on beta cell function is controversial. Methods: In 62 non-diabetic women and men (age 24-69 years, BMI 21-39 kg/m 2 ), we measured VAT and subcutaneous adipose tissue (SAT) fat mass by magnetic resonance imaging. We also measured insulin secretion and beta cell function by C-peptide deconvolution and physiological modelling of data from a frequently sampled, 75-g, 3-h OGTT, respectively. Results: VAT (range 0.1-3.1 kg) was strongly related to sex, age and BMI; SAT was related to sex and BMI. Controlling for sex, age, BMI and SAT by multivariate analysis, excess VAT was associated with a clinical phenotype comprising higher plasma glucose levels, BP, heart rate and serum transaminases. The corresponding metabolic phenotype consisted of insulin resistance (partial r=−0.38) and hyperinsulinaemia (partial r=0.29). The latter, however, was appropriate for the degree of insulin resistance regardless of obesity and abdominal fat distribution. Moreover, none of the model-derived parameters describing beta cell function (glucose sensitivity, rate sensitivity and potentiation) was independently associated with excess VAT. Conclusions/interpretation: In non-diabetic Caucasian adults of either sex, preferential visceral fat deposition in itself is part of an insulin-resistant phenotype. The insulin secretory response to a physiological challenge is increased to fully compensate for the insulin resistance, but the dynamics of beta cell function (glucose sensitivity, rate sensitivity and potentiation) are largely preserved.

Neuroimaging plays a major role in the evaluation of patients with neurologic disorders. The utility of various neuroimaging studies is rapidly increasing in both clinical and research settings. Neurologists should learn about the technical aspects, indications, and ...

BACKGROUND Cardiovascular magnetic resonance imaging (CMR) has been utilized for diagnosis in various cardiovascular diseases and most of those were performed on a 1.5 Tesla CMR system. Recently, a 3.0 Tesla magnetic resonance imaging system has been introduced into clinical practice, however the clinical experience on cardiovascular examination using this system is limited. Therefore, the authors&#39; institution has integrated a team for developing a CMR program on this 3.0 Tesla system. OBJECTIVE To describe the authors&#39; experience on the 3.0 Tesla CMR system. MATERIAL AND METHOD The data on patients referred to the authors&#39; CMR unit between August 2004 and October 2005 were reviewed. RESULTS One hundred patients were referred for CMR examination. The mean age was 56 years (2 month - 85 years) and 65 patients were male. The most common indication was to assess coronary artery disease (64 patients). The performed examination was divided into cardiac structure and function ...

The purpose of this study was to determine the relationship between anterior knee pain secondary to suspected patellofemoral malalignment and tibial tubercle lateralization, patellar tilt, and patellar lateralization on magnetic resonance imaging. Methods: We compared the bony relationships of the knee in patients with anterior knee pain and patients with nonspecific internal derangements of the knee. We measured the lateral deviation of the tibial tubercle and the patella from the trochlea, patellar tilt, and patellar and patellar tendon length. Results: The symptomatic knees of patients with anterior knee pain had significantly (P Յ .01) greater lateralization of the tibial tubercle and lateral patellar tilt than did knees of the control group. Patella alta appears to be more common in subjects with anterior knee pain. Conclusions: Magnetic resonance imaging determination of tibial tubercle lateralization and patellar tilt correlates positively with the clinical diagnosis of anterior knee pain, suggesting that patellofemoral pain is caused by subtle malalignment. Level of Evidence: Level III, development of diagnostic criteria on basis of nonconsecutive patients.