Indications For Magnetic Resonance Imaging Research Articles

Optic nerve diffusion changes and atrophy jointly predict visual dysfunction after optic neuritis

Recently, there has been strong interest in the development of imaging techniques to quantify axonal and myelin pathology in patients with multiple sclerosis (MS). Optic neuritis, a condition characterised by inflammatory demyelination of the optic nerve, is one of the commonest sites of MS relapse, and exhibits similar pathological alterations to MS lesions elsewhere in the central nervous system (CNS). Unlike other regions of the CNS, however, the function of the optic nerve can be accurately assessed using clinical measures, as well as electrophysiological techniques such as visual evoked potential recordings. Therefore, optic neuritis is useful for investigating the relationship between abnormalities in optic nerve structure, assessed using magnetic resonance imaging (MRI), and visual dysfunction, assessed clinically and electrophysiologically. The aims of the present study were to assess optic nerve structural abnormalities in patients with a history of unilateral optic neuritis using MRI, and then to identify correlations between abnormalities in optic nerve MRI and visual dysfunction. Ten controls and sixteen patients underwent high resolution optic nerve diffusion tensor imaging (DTI), T2- and T1-weighted MRI. In addition, Snellen visual acuity and the latency and amplitude of multifocal visual evoked potentials (mfVEP) were tested in all patients. Diffusion and volumetric MRI indices were correlated to mfVEP functional indices. Significant abnormalities were detected in MRI and mfVEP measures in patients' affected nerves compared to unaffected optic nerves or optic nerves from healthy controls. Reduced mfVEP amplitude in the affected side significantly correlated with both affected optic nerve atrophy (R=0.58, p=0.02) and reduced fractional anisotropy (FA) (R=0.52, p=0.04). However, atrophy and reduced FA did not correlate with each other. To further investigate this disassociation, we used linear regression analysis with optic nerve atrophy and optic nerve FA as independent variables and mfVEP amplitude as the dependent variable. The resulting linear regression model was highly significant (R=0.819, p=0.001). These results show that, 4 years after unilateral optic neuritis, MRI-based measures of optic nerve structural abnormalities (decreased anisotropy and volume) independently predict visual dysfunction.

Association of matrix metalloproteinases with MRI indices of brain ischemia and aging

Magnetic resonance imaging (MRI) findings of large white matter hyperintensities (LWMH), decreased brain volume and silent cerebral infarcts (SCI) are subclinical indices of brain ischemia and aging. Although the pathophysiology of these findings remains uncertain, extracellular matrix (ECM) remodeling, a process regulated by matrix metalloproteinases (MMPs) and their inhibitors (TIMPs), may be implicated. We evaluated the cross-sectional relations of circulating MMP-9 and TIMP-1 to these MRI indices in 583 stroke and dementia-free, Framingham Offspring participants (mean age 57 years, 58% women). Using multivariable regression MMP-9 (detectable versus non-detectable) and TIMP-1 (modeled as sex-specific quartiles) were related to LWMH (>1S.D. above age-specific mean; yes/no), SCI (yes/no) and total brain volume (ratio of parenchymal to intracranial volume, TCBVr). Mean TCBVr was 0.78 (S.D. 0.03), 13% of subjects had LWMH and 12% had SCI. Detectable MMP-9 was associated with higher prevalence of LWMH (OR 2.09, 95%confidence interval (CI) 1.00-4.37), but not with TCBVr. TIMP-1 was associated with a high prevalence of LWMH (OR for Q4 versus Q1-3: 1.83, 95%CI 1.06-3.18) and with lower mean TCBVr (Q4 associated with 0.17 S.D. units lower value relative to Q1-3; p=0.04). Neither biomarker was associated with SCI. Our findings are preliminary but if confirmed in further studies, suggest a pathophysiological role for the MMP/TIMP pathway in processes of brain ischemia and aging.

Intradiscal injection of simvastatin retards progression of intervertebral disc degeneration induced by stab injury

IntroductionEarlier work indicates that the cholesterol-lowering drug, simvastatin, is anabolic to chondrogenic expression of rat intervertebral disc (IVD) cells, which suggests a potential role for simvastatin in IVD regeneration. In this study, we expand on our earlier work to test the effectiveness of simvastatin on disc degeneration utilizing a rat tail disc degeneration model.Methods30 rats that underwent 21 G needle-puncture at rat tail discs were injected with simvastatin-loaded poly(ethylene glycol)-poly(lactic acid-co-glycolic acid)-poly(ethylene glycol) (PEG-PLGA-PEG) gel (5 mg/ml) or vehicle control at 4 weeks after needle injury. All animals were sacrificed 2 weeks after simvastatin injection. Bone morphogenetic protein-2 (BMP-2), aggrecan, collagen type II, and collagen type I messenger ribonucleic acid (mRNA) expression in the rat nucleus pulposus (NP) were measured by real-time polymerase chain reaction (PCR). In vivo magnetic resonance imaging (MRI) was performed to monitor changes in disc degeneration. Rat discs were also assessed by histology using hematoxylin and eosin (H&E) and safranin O staining. In addition, the NP weight, glycosaminoglycan (sGAG) and DNA content were also measured.ResultsA single dose of simvastatin loaded in thermo-sensitive PEG-PLGA-PEG gel injected into the NP had the trend to increase aggrecan expression and sGAG content, and significantly increased mRNA levels of BMP-2, collagen type II, and the differentiation index (the ratio of collagen type II to collagen type I). The decreased NP weight, T2 intensity, as well as MRI index in the rat tail discs induced by needle puncture were significantly reversed after 2 weeks of simvastatin treatment. In addition, simvastatin treatment also improved histological changes induced by needle puncture.ConclusionsA single injection of simvastatin loaded in PEG-PLGA-PEG gel into rat tail discs had the potential to retard or regenerate the degenerative disc.

Abstract 5734: Left Ventricular Torsion Reflects Degree of Myocardial Fibrosis in Hypertrophic Cardiomyopathy

Background : LV torsion (LVtor) is reduced in patients with impaired LV systolic function, e.g., dilated cardiomyophaty. It used to be thought that LVtor is reduced in patients with hypertrophic caridiomyopathy (HCM) because of the myocardial disarray; however, recent observation showed that LVtor assessed with tagged magnetic resonance imaging (MRI) even increased in patients with HCM. Recently LVtor is assessable with novel ultrasound speckle tracking imaging (STI) method. This technique may be used to assess intra-ventricular torsion in the LV muscle (intra-LVtor) that occurs due to the different fiber directions between the endocardium and epicardium. In this study, we analyzed LVtor and intra-LVtor in light of LV fibrosis in patients with HCM. Methods : MRI and echo studies were performed in 10 patients with HCM in whom any medication had not been given to HCM. MRI was used to determine LV mass index. In addition, %DEmass was determined as an MRI index of the extent of myocardial fibrosis by dividing the extent of late gadolinium enhancement by LV mass. We acquired basal and apical short-axis LV images with 2D echocardiography for off-line STI analysis to determine LVtor and intra-LVtor. We traced 18 points of the endcardium and epicardium, respectively, and averaged all regional rotation at the basal and apical plane, respectively. LVtor was defined as the difference of LV rotation between the basal and apical plane. Intra-LVtor was defined as the difference in the rotation between the endcardium and epicardium. Results : There was a significant correlation between %DEmass and LVtor(r=−0.72, p<0.05, indicating that LVtor is reduced in HCM patients with larger extent of LV myocardial fibrosis. There was no significant correlation between LVtor and LV mass index (r=−0.15, p=n.s.). %DEmass also correlated with intra-LVtor (r=−0.67, p<0.05, indicating that intra-LVtor is reduced in HCM patients with larger extent of LV myocardial fibrosis. Conclusions : Both LV torsion and intra-LV torsion are reduced in HCM patients with extended LV fibrosis. In other words, the extent of myocardial fibrosis may be assessed with LVtor and intra-LVtor by use of speckle tracking imaging in patients with HCM.

Characterization of Intervertebral Disc Aging

A cohort of young, healthy New Zealand White rabbits was followed longitudinally with serial magnetic resonance imaging (MRI) analysis and terminal analysis of histologic changes and gene expression. To examine the changes observed during normal aging in the intervertebral disc. Although there is a correlation between aging and the onset of intervertebral disc degeneration (IDD), evidence suggests that distinct pathways are involved in these processes. Our group has characterized a reproducible rabbit model of IDD by MRI, radiograph, histology, and mRNA expression. However, no similar analysis has been performed longitudinally for intervertebral disc aging to allow comparison of these 2 important processes. Four skeletally mature female NZW rabbits were housed for 122 weeks, and lumbar spine MRIs were characterized serially. Histologic and quantitative gene expression analysis of the nucleus pulposus of these aging animals was performed, and compared with adult and young rabbits. Mean MRI index decreased by <25% through 120 weeks. The histologic analysis showed changes in cell composition, with abundant notochordal cells in the young, chondrocyte-like cells and notochordal cells in the adult, and clusters of hypertrophic chondrocytes in the aging discs. The PCR analysis of the nucleus pulposus showed that gene expression of collagen decreased, whereas that for proteoglycans increased with aging. BMP-2, TIMP-1, and SOX-9 expression was significantly lower in the young compared with adult discs and TGF-beta1 demonstrated lower gene expression in young and aging animals. Although dramatic cellular changes were observed, age-related MRI changes occurred in this rabbit model of normal aging at a much slower rate than in a previous injury model of degeneration. In addition, the gene expression analysis of the nucleus pulposus demonstrated remarkable differences between aging and injury induced degeneration. These results suggest that aging and injury contribute uniquely to the process of IDD.

Aging of cerebral white matter: a review of MRI findings

Cerebral aging is a complex and heterogeneous process that is associated with a high degree of inter-individual variability. Structural magnetic resonance imaging (MRI) can be used to identify and quantify non-disease-related aging of the cerebral white matter. The present article reviews the findings from several MRI techniques, including morphometric approaches, study of white matter hyperintensities, diffusion tensor imaging, and magnetization transfer imaging, that have been used to examine aging of the cerebral white matter. Furthermore, the relationship of MRI indices of white matter integrity to age-related cognitive declines is reported. A general pattern of age-related preservation and decline emerges indicating that the prefrontal white matter is most susceptible to the influence of age. Studies that combine MRI with cognitive measures suggest that such age-related reductions in white matter integrity may produce a disconnection state that underlies some of the age-related performance declines in age-sensitive cognitive domains. White matter aging may contribute to a disconnection state that is associated with declines in episodic memory, executive functions, and information processing speed.

Adalimumab significantly reduces both spinal and sacroiliac joint inflammation in patients with ankylosing spondylitis: A multicenter, randomized, double‐blind, placebo‐controlled study

To compare the efficacy of adalimumab versus placebo in reducing spinal and sacroiliac (SI) joint inflammation, by magnetic resonance imaging (MRI) in patients with active ankylosing spondylitis (AS). This was a randomized, multicenter, double-blind, placebo-controlled study. Patients (n = 82) received 40 mg adalimumab or placebo every other week during an initial 24-week double-blind period. MRIs of both the spine and SI joints were obtained at baseline, week 12, and week 52. Spinal and SI joint inflammation were measured using the Spondyloarthritis Research Consortium of Canada (SPARCC) MRI index. The spine SPARCC score in placebo-treated patients increased by a mean of 9.4% from baseline, compared with a mean decrease of 53.6% in adalimumab-treated patients (P < 0.001); the SI joint SPARCC score decreased by a mean of 12.7% from baseline in placebo-treated patients and by 52.9% in adalimumab-treated patients (P = 0.017). The response in adalimumab-treated patients was maintained at week 52. Placebo-treated patients were switched to open-label adalimumab treatment at week 24 and experienced similar reductions in spinal and SI joint inflammation by week 52. Similar large reductions in the spine and SI joint SPARCC scores were noted, even in patients who failed to meet the ASsessment in Ankylosing Spondylitis (International Working Group) criteria (nonresponders) at 12 weeks. In adalimumab-treated patients, a reduced C-reactive protein concentration at week 12 was significantly associated with improvement in the spine SPARCC score (P = 0.018). Adalimumab significantly reduced both spinal and SI joint inflammation in patients with active AS after 12 weeks of treatment, and these improvements were maintained for up to 52 weeks.

MR Imaging Index for Differentiation of Progressive Supranuclear Palsy from Parkinson Disease and the Parkinson Variant of Multiple System Atrophy

To prospectively assess sensitivity and specificity of magnetic resonance (MR) imaging measurements of midbrain, pons, middle cerebellar peduncles (MCPs), and superior cerebellar peduncles (SCPs) for differentiating progressive supranuclear palsy (PSP) from Parkinson disease (PD) and Parkinson variant of multiple system atrophy (MSA-P), with established consensus criteria as reference standard. All study participants provided informed consent; study was approved by the institutional review board. Pons area, midbrain area, MCP width, and SCP width were measured in 33 consecutive patients with PSP (16 possible, 17 probable), 108 consecutive patients with PD, 19 consecutive patients with MSA-P, and 50 healthy control participants on T1-weighted MR images. The pons area-midbrain area ratio (P/M) and MCP width-SCP width ratio (MCP/SCP) were also used, and an index termed MR parkinsonism index was calculated [(P/M).(MCP/SCP)]. Differences in MR imaging measurements among groups were evaluated with Kruskal-Wallis test, Mann-Whitney U test, and Bonferroni correction. Midbrain area and SCP width in patients with PSP (23 men, 10 women; mean age, 69.3 years) were significantly (P < .001) smaller than in patients with PD (62 men, 46 women; mean age, 65.8 years), patients with MSA-P (five men, 14 women; mean age, 64.0 years), and control participants (25 men, 25 women; mean age, 66.6 years). P/M and MCP/SCP were significantly larger in patients with PSP than in patients in other groups and control participants. All measurements showed some overlap of values between patients with PSP and patients from other groups and control participants. MR parkinsonism index value was significantly larger in patients with PSP (median, 19.42) than in patients with PD (median, 9.40; P < .001), patients with MSA-P (median, 6.53; P < .001), and control participants (median, 9.21; P < .001), without overlap of values among groups. No patient with PSP received a misdiagnosis when the index was used (sensitivity and specificity, 100%). The MR parkinsonism index can help distinguish patients with PSP from those with PD and MSA-P on an individual basis.

Multiparametric magnetic resonance imaging analysis of the corticospinal tract in multiple sclerosis☆

Muscle weakness is an important feature of multiple sclerosis and is responsible for much of the disability associated with that condition. Here, we describe the quantitative magnetic resonance imaging (MRI) attributes of the major intracerebral motor pathway--the corticospinal tract--in multiple sclerosis. To do so, we develop an intuitive method for creating and displaying spatially normalized tract-specific imaging data. In 75 individuals with multiple sclerosis and 29 healthy controls, the corticospinal tracts were reconstructed from diffusion tensor imaging at 3 T. Multiple MRI indices--T2 relaxation time; fractional anisotropy; mean, longitudinal, and transverse diffusivity; and magnetization transfer ratio--were examined within the reconstructed tracts. Spatially normalized tract profiles were created to compare, across subjects, the variation in MRI index as a function of tract position. Each index's tract profile had a characteristic shape. Individual subjects had markedly abnormal tract profiles, particularly at lesion sites. On average, tract profiles were different between patients and controls, particularly in the subcortical white matter and corona radiata, for all indices examined except for fractional anisotropy. Magnetization transfer ratio was further decreased in subjects with secondary progressive disease. Tract asymmetry was increased in multiple sclerosis compared to controls. Multiparametric MRI allows rapid detection, localization, and characterization of tract-specific abnormalities in multiple sclerosis. Tract profiles bridge the gap between whole-brain imaging of neurological disease and the interrogation of individual, functionally relevant subsystems.

Infarct Tissue Heterogeneity by Magnetic Resonance Imaging Identifies Enhanced Cardiac Arrhythmia Susceptibility in Patients With Left Ventricular Dysfunction

The extent of the peri-infarct zone by magnetic resonance imaging (MRI) has been related to all-cause mortality in patients with coronary artery disease. This relationship may result from arrhythmogenesis in the infarct border. However, the relationship between tissue heterogeneity in the infarct periphery and arrhythmic substrate has not been investigated. In the present study, we quantify myocardial infarct heterogeneity by contrast-enhanced MRI and relate it to an electrophysiological marker of arrhythmic substrate in patients with left ventricular (LV) systolic dysfunction undergoing prophylactic implantable cardioverter defibrillator placement. Before implantable cardioverter defibrillator implantation for primary prevention of sudden cardiac death, 47 patients underwent cine and contrast-enhanced MRI to measure LV function, volumes, mass, and infarct size. A method for quantifying the heterogeneous infarct periphery and the denser infarct core is described. MRI indices were related to inducibility of sustained monomorphic ventricular tachycardia during electrophysiological or device testing. For the noninducible versus inducible patients, LV ejection fraction (30+/-10% versus 29+/-7%, P=0.79), LV end-diastolic volume (220+/-70 versus 228+/-57 mL, P=0.68), and infarct size by standard contrast-enhanced MRI definitions (P=NS) were similar. Quantification of tissue heterogeneity at the infarct periphery was strongly associated with inducibility for monomorphic ventricular tachycardia (noninducible versus inducible: 13+/-9 versus 19+/-8 g, P=0.015) and was the single significant factor in a stepwise logistic regression. Tissue heterogeneity is present and quantifiable within human infarcts. More extensive tissue heterogeneity correlates with increased ventricular irritability by programmed electrical stimulation. These findings support the hypothesis that anatomic tissue heterogeneity increases susceptibility to ventricular arrhythmias in patients with prior myocardial infarction and LV dysfunction.

Skeletal Muscle Degeneration and Regeneration after Femoral Artery Ligation in Mice: Monitoring with Diffusion MR Imaging

To prospectively evaluate quantitative diffusion magnetic resonance (MR) imaging for monitoring skeletal muscle injury and repair after femoral artery ligation in mice. All experimental procedures were approved by the local institutional animal care and use committee. Muscle degeneration and regeneration were induced in 16 mice by using unilateral ligation of the femoral artery. Diffusion-tensor and T2-weighted MR imaging examinations were performed before, immediately after, and 3, 10, and 21 days after ligation. Histologic analysis was also performed at these time points. The dynamic changes in T2 and in five diffusion-tensor imaging indexes were studied by using histogram analysis. Differences between the ligated and nonligated limbs were assessed with paired t tests, and analysis of variance was used to determine temporal evolutions. Parametric maps were clustered to depict regional differences in the responses of the different MR imaging indexes. MR indexes in the ligated limb changed over time (P < .007), and temporal evolutions in the ligated and nonligated limbs differed significantly (P < .001). When ischemia was induced, diffusivity and T2 increased, with a maximum change at 3 days, when most muscle damage was observed at histologic analysis. At 10 days, diffusion values were reduced overall, whereas T2 was still increased. At 21 days, parameter values had largely returned to normal. Changes on the diffusion-tensor and T2 maps had spatial differences, which corresponded to the different phases of tissue regeneration observed at histologic analysis. An additional finding was the transient change in direction of the principal eigenvector during the period of maximal muscle damage. After femoral artery ligation, the diffusion-tensor indexes changed dynamically in association with the severity and location of muscle damage.

MRI for the determination of pituitary iron overload in children and young adults with β-thalassaemia major

Hypogonadism, resulting from iron-induced pituitary dysfunction, is the most frequently reported complication in patients with β-thalassaemia major. The aim of this study was to evaluate pituitary Magnetic Resonance Imaging (MRI) signal intensity reduction, on T2*-weighted images, as a marker of pituitary iron overload. Thirty patients (13 females and 17 males, mean age: 16.6 ± 4.1) with β-thalassaemia major on conventional treatment and 13 healthy volunteers (7 females and 6 males, mean age: 11 ± 4.51 years) were studied with T2*-weighted images of the anterior pituitary using a 1.5 T unit. Four thalassaemic patients (2 females and 2 males) had clinical hypogonadism and required hormonal replacement treatment. Results revealed a statistically significant reduction of pituitary signal intensity in the thalassaemia group compared to controls ( p < 0.001). Moreover, hypogonadal patients had significantly decreased MRI values compared to thalassaemic patients without hypogonadism ( p = 0.017). Relatively decreased adeno-hypophyseal MRI signal intensity was recorded in pubertal thalassaemic patients. A significant negative correlation was observed between pituitary MRI values and age ( r = −0.67, r 2 = 0.443, p = 0.001), whereas ferritin levels and pituitary MRI values were moderately correlated ( r = −0.56, r 2 = 0.32, p = 0.08) in adult thalassaemic patients. In conclusion, pituitary MRI indices as measured on T2*-weighted images seem to reflect pituitary iron overload and could, therefore, be used for a preclinical detection of patients who are in greater danger of developing hypogonadism.

Methodology of clinical trials in multiple sclerosis

The scope of the paper is to summarise key issues in methodology used in clinical trials on multiple sclerosis (MS) treatment and help clinicians to better understand articles reporting the results of these trials. Relapsing ratio and disability progression based on the Expanded Disability Status Scale are currently used as clinical efficacy primary outcomes, but more global measurements should be used in future such as the MS Functional Composite. For magnetic resonance imaging (MRI) outcomes, new MRI composites and indexes are already available (Z4 score, conventional MRI-derived end-points) that, together with new MRI techniques (magnetisation- transfer MRI and proton resonance spectroscopy), offer more precise neuroimaging assessments of the disease. These efficacy measurements should be presented in articles as number needed to treat, which assists the reader to calculate and compare the treatments' power and safety.

Linear measures of temporal lobe atrophy on brain magnetic resonance imaging (MRI) but not visual rating of white matter changes can help discrimination of mild cognitive impairment (MCI) and Alzheimer's disease (AD)

Clinical discrimination of the early stages of AD and MCI is challenging. MRI indices which are simple enough to be applied by non-radiologists on hard copies would be of practical importance in the discrimination. We studied 45 consecutive patients (17 with MCI, 25 with AD, 3 with normal cognitive findings) with at least one white matter lesion (WML) on axial fluid-attenuated inversion recovery (FLAIR) MRI sequences. WML load was evaluated by Fazekas’ scoring system; temporal lobe atrophy by interuncal distance (IUD) measurement. WML pattern had no significant discriminative value of AD and MCI. No significant correlation between periventricular/subcortical WML scores and neuropsychological test results was observed. The mean IUD was significantly smaller in patients with MCI compared to those with AD. The cut-off value of IUD was 28.3 mm with receiver operating curve (ROC) analysis. Area under the curve was 0.925 (95% CI: 0.800–0.983). A significant negative correlation between IUD and the mini mental state examination (MMSE), verbal fluency, clock drawing, and Rey Auditory verbal learning test (AVLT) was noted. The results indicate that measurement of IUD is a clinically useful test in discrimination of AD and MCI patients with WML(s) on brain MRI. However, severity of these lesions is not useful for distinctions.

Spondyloarthritis research Consortium of Canada magnetic resonance imaging index for assessment of sacroiliac joint inflammation in ankylosing spondylitis

To develop a feasible magnetic resonance imaging (MRI)-based scoring system for sacroiliac joint inflammation in patients with ankylosing spondylitis (AS) that requires minimal scan time, does not require contrast enhancement, evaluates lesions separately at each articular surface, and limits the number of sacroiliac images that are scored. A scoring method based on the assessment of increased signal denoting bone marrow edema on T2-weighted STIR sequences was used. MRI films were assessed blindly in random order at 2 sites by multiple readers. Intra- and interreader reliability was assessed by intraclass correlation coefficient (ICC); the 24-week response of patients with AS randomized to placebo:infliximab (3:8) was assessed by effect size and standardized response mean. The reliability and responsiveness of the scoring method were compared for STIR and gadolinium diethylenetriaminepentaacetic (Gd-DTPA)-enhanced MRI sequences. We scanned 11 patients with AS with clinically active disease and 11 additional patients randomized to the trial of infliximab therapy. ICC for total sacroiliac joint STIR score ranged from 0.90 to 0.98 (P < 0.00001) and interobserver ICC for combined readers from the 2 sites was 0.84 (P < 0.0001). ICC for change scores was lower for STIR (ICC 0.53) than for Gd-DTPA-enhanced sequences (ICC 0.79). Responsiveness was poor, although fusion was evident in one-third of patients who received treatment (placebo:infliximab) and inflammation scores were low. The Spondyloarthritis Research Consortium of Canada MRI index is a feasible and reproducible index for measuring sacroiliac joint inflammation in patients with AS.

Spondyloarthritis research consortium of canada magnetic resonance imaging index for assessment of spinal inflammation in ankylosing spondylitis

To develop a feasible magnetic resonance imaging (MRI)-based scoring system for spinal inflammation in patients with spondylarthropathy that requires minimal scan time, does not require contrast enhancement, evaluates the extent of lesions in 3 dimensional planes, and limits the number of vertebral levels that are scored because MRI demonstrates characteristic inflammatory lesions in the spine of patients with ankylosing spondylitis (AS) prior to the development of typical features on plain radiographic. Our scoring method was based entirely on the assessment of increased signal denoting bone marrow edema on T2-weighted STIR sequences. Blinded MRI films were assessed in random order at 2 sites by 3 blinded readers at each of the 2 sites (the Universities of Alberta and Toronto). Intra- and interreader reliability was assessed by intraclass correlation coefficient. The 24-week response of patients with AS randomized to infliximab:placebo (8:3) was assessed by effect size and standardized response mean. An initial analysis of all discovertebral units (DVUs) in the spine of 11 patients demonstrated a mean of 3.2 (95% confidence interval 3.2, 5.2) affected units, while limiting the scoring to a maximum of 6 units captured most of the affected units. We scanned 11 patients with AS with clinically active disease and 20 additional patients randomized to a 24-week trial of either infliximab or placebo. Intraobserver reproducibility for the 6-DVU STIR score ranged from 0.93 to 0.98 (P < 0.0001). Interobserver reproducibility of scores by readers from both sites was 0.79 (P < 0.0001) for status score and 0.82 (P < 0.0001) for change score. Analysis of pretreatment and posttreatment scores for all 20 patients randomized to infliximab/placebo showed a large degree of responsiveness (standardized response mean = 0.87). Reproducibility and responsiveness were only slightly improved by using contrast enhancement with gadolinium diethylenetriaminepentaacetic acid. The Spondyloarthritis Research Consortium of Canada MRI index is a feasible, reproducible, and responsive index for measuring spinal inflammation in AS.

Analysis of Combined Treatment of Embolic Stroke in Rat with r-tPA and a GPIIb/IIIa Inhibitor

Suppression of platelet activation improves the efficacy of thrombolytic therapy for stroke. Thus, combination treatment with recombinant tissue plasminogen activator (r-tPA) and 7E3 F(ab')2, a GPIIb/IIIa inhibitor that binds the platelet to fibrin, may improve the efficacy of thrombolytic therapy in embolic stroke. Magnetic resonance imaging (MRI) was used to monitor treatment response in rats subjected to embolic middle cerebral artery (MCA) occlusion (MCAo). Animals were randomized into treated (n=12) and control (n=10) groups and received intravenous combination therapy or saline, respectively, 4 hours after MCAo. Magnetic resonance imaging (MRI) measurements performed 1 hour after MCAo showed no difference between groups. However, an increased incidence (50%) of MCA recanalization was found in the treated group at 24 hours compared with 20% in the control group. The area of low cerebral blood flow at 24 and 48 hours was significantly smaller in the combination treatment group, and the lesion size, as indicated from the T2 and T1 maps, differed significantly between groups. Fluorescence microscopy measurements of cerebral microvessels perfused with fluorescein isothiocyanate-dextran and measurements of infarct volume revealed that the combination treatment significantly increased microvascular patency and reduced infarct volume, respectively, compared with the control rats. The efficacy of combination treatment 4 hours after ischemia is reflected by MRI indices of tissue perfusion, MCA recanalization, and reduction of lesion volume. The treatment also reduced secondary microvascular perfusion deficits.

Clinical and imaging predictors of intracerebral haemorrhage in stroke patients treated with intravenous tissue plasminogen activator

Objective: To evaluate clinical, biological, and pretreatment imaging variables for predictors of tissue plasminogen activator (tPA) related intracerebral haemorrhage (ICH) in stroke patients. Methods: 48 consecutive patients with hemispheric stroke...

The use of quick-brain magnetic resonance imaging in the evaluation of shunt-treated hydrocephalus

Children with shunt-treated hydrocephalus are exposed to serious amounts of radiation when undergoing computerized tomography (CT) scanning. The authors report their clinical experience with single-shot fast-spin echo (SSFSE) (quick-brain) magnetic resonance (MR) imaging as the modality of choice for the workup and follow up of patients in whom a shunt has been placed to treat hydrocephalus. A retrospective chart review was performed to obtain data on all cases in which a quick-brain MR image was acquired for either symptomatic workup or asymptomatic follow-up examination of shunt-treated hydrocephalus. Data regarding demographics, origin of hydrocephalus, MR imaging indications and findings, use of sedation, imaging-related complications, use of adjunctive CT scanning, details of shunt revision, and cause of shunt malfunction were collected. The authors found that SSFSE MR imaging is a sufficient, radiation-free diagnostic alternative to CT scanning that minimizes movement artifact and duration of scanning and eliminates the need for sedation. In light of these findings, the authors propose that quick-brain MR imaging replace CT scanning as the diagnostic modality of choice in examining and following shunt-treated patients because it offers significant advantages.

Breast reconstruction with a transverse rectus abdominis myocutaneous flap: spectrum of normal and abnormal MR imaging findings.

The authors retrospectively reviewed their clinical database for cases of breast magnetic resonance (MR) imaging performed in women who had undergone breast reconstruction with a transverse rectus abdominis myocutaneous (TRAM) flap. Patient histories, MR imaging results, and, when available, biopsy results were reviewed. During a 4-year period, 24 neobreasts were imaged in 22 women who had undergone TRAM flap reconstruction after mastectomy. In most of the cases (64%), the indication for MR imaging was a palpable abnormality or pain. In four of 24 cases (17%), recurrent breast cancer was detected. These cases consisted of a local chest wall tumor (n = 2), an infiltrating chest wall tumor (n = 1), and axillary nodal recurrence (n = 1). In all four cases, MR imaging demonstrated a suspicious lesion or abnormality. In 11 of 24 cases (46%), benign findings only were demonstrated. These consisted of localized or diffuse skin thickening, fibrosis, fat necrosis, and seroma. In nine of 24 cases (38%), no pathologic abnormality was identified. MR imaging is useful in detection of locally recurrent tumor in patients who have undergone breast reconstruction with a TRAM flap. MR imaging allows differentiation between benign and malignant findings in patients with palpable abnormalities or pain after TRAM flap reconstruction.