Lack of progression of brain abnormalities in first-episode psychosis: a longitudinal magnetic resonance imaging study

Background. Some neuroimaging studies have supported the hypothesis of progressive brain changes after a first episode of psychosis. We aimed to determine whether (i) first-episode psychosis patients would exhibit more pronounced brain volumetric changes than controls over time and (ii) illness course/treatment would relate to those changes. Method. Longitudinal regional grey matter volume and ventricle : brain ratio differences between 39 patients with first-episode psychosis (including schizophrenia and schizophreniform disorder) and 52 non-psychotic controls enrolled in a population-based case-control study. Results. While there was no longitudinal difference in ventricle : brain ratios between first-episode psychosis subjects and controls, patients exhibited grey matter volume changes, indicating a reversible course in the superior temporal cortex and hippocampus compared with controls. A remitting course was related to reversal of baseline temporal grey matter deficits. Conclusions. Our findings do not support the hypothesis of brain changes indicating a progressive course in the initial phase of psychosis. Rather, some brain volume abnormalities may be reversible, possibly associated with a better illness course.

Changes in Perfusion-Weighted Magnetic Resonance Imaging after Carotid Angioplasty with Stent

Carotid artery stenosis due to arteriosclerosis increases the risk of cerebral ischemia via embolic phenomena or reduced blood flow. The changes in cerebral perfusion that may occur after treatment are not clearly understood. This study evaluated the changes in cerebral microcirculation following carotid angioplasty with stenting (CAS) under cerebral protection with filters using ultrafast gradient echo (GRE) perfusion weighted imaging (PWI) with magnetic resonance imaging (MRI). Prospectively, 21 cervical carotid stenosis patients, mean age 69.95 years, underwent MRI 12 h before and 72 h after CAS. PWI parameters were collected for statistical analysis: cerebral blood volume (CB V), mean transit time (MTT) and time to peak (TTP). Statistical analysis was applied to absolute parameters and to values normalized against those from the contralateral parenchyma. The main finding of this study was improved hemodynamics for the normalized data after CAS, shown by reduced MTT (p<0.001) and TTP (p=0.019) in the territory fed by the middle cerebral artery ipsilateral to the CAS. Absolute data showed increased blood volume in the cerebral hemispheres after CAS, which was more accentuated on the stent side (p=0.016) than the contralateral side (p=0.029). Early improvements in cerebral perfusion, mainly seen in the normalized data, were clearly demonstrated in the timing parameters - TTP & MTT - after CAS.

Normal metabolite levels in the left dorsolateral prefrontal cortex of unmedicated major depressive disorder patients: A single voxel (1)H spectroscopy study

Few proton magnetic resonance spectroscopy ((1)H spectroscopy) studies have investigated the dorsolateral prefrontal cortex (DLPFC), a key region in the pathophysiology of major depressive disorder (MDD). We used (1)H spectroscopy to verify whether MDD patients differ from healthy controls (HQ in metabolite levels in this brain area. Thirty-seven unmedicated DSM-IV MDD patients were compared with 40 HC. Subjects underwent a short echo-time (1)H spectroscopy examination at 1.5 T, with an 8-cm(3) single voxel placed in the left DLPFC. Reliable absolute metabolite levels of N-acetyl aspartate (NAA), phosphocreatine plus creatine (PCr+Cr), choline-containing compounds (GPC+PC), myo-inositol, glutamate plus glutamine (Glu+Gln), and glutamate were obtained using the unsuppressed water signal as an internal reference. Metabolite levels in the left DLPFC did not statistically differ between MDD patients and HC. We found an interaction between gender and diagnosis on PCr+Cr levels. Male MDD patients presented lower levels of PCr+Cr than male HC, and female MDD patients presented higher levels of PCr+Cr than female HC. Moreover, length of illness was inversely correlated with NAA levels. These findings suggest that there is not an effect of diagnosis on the left DLPFC neurochemistry. Possible effects of gender on PCr+Cr levels of MDD patients need to be further investigated. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Contrast-enhanced magnetic resonance imaging identifies focal regions of intramyocardial fibrosis, in patients with severe aortic valve disease: Correlation with quantitative histopathology

Background Chronic aortic valve disease (AVD) is characterized by progressive accumulation of interstitial myocardial fibrosis (MF). However, assessment of MF accumulation has only been possible through histologic analyses of endomyocardial biopsies. We sought to evaluate contrast-enhanced magnetic resonance imaging (ce-MRI) as a noninvasive method to identify the presence of increased MF in patients with severe AVD. Methods Seventy patients scheduled to undergo aortic valve replacement surgery were examined by cine and ce-MRI in a 1.5-T scanner. Cine images were used for the assessment of left ventricular (LV) volumes, mass, and function. Delayed-enhancement images were used to characterize the regions of MF. In addition, histologic analyses of myocardial samples obtained during aortic valve replacement surgery were used for direct quantification of interstitial MF. Ten additional subjects who died of noncardiac causes served as controls for the quantitative histologic analyses. Results Interstitial MF determined by histopathologic analysis was higher in patients with AVID than in controls (2.7% +/- 2.0% vs 0.6% +/- 0.2%, P =.001). When compared with histopathologic results, ce-MRI demonstrated a sensitivity of 74%, a specificity of 81%, and an accuracy of 76% to identify AVD patients with increased interstitial MF There was a significant inverse correlation between interstitial MF and LV ejection fraction (r = -0.67, P <.0001). Accordingly, patients with identifiable focal regions of MF by ce-MRI exhibited worse LV systolic function than those without MF (45% +/- 14% vs 65% +/- 14%, P <.0001). Conclusions Contrast-enhanced MRI allows for the noninvasive detection of focal regions of MF in patients with severe AVD. Moreover, patients with identifiable MF by ce-MRI exhibited worse LV functional parameters. (Am Heart J 2009; 157:361-8.)

High prevalence of pituitary magnetic resonance abnormalities and gene mutations in a cohort of Brazilian children with growth hormone deficiency and response to treatment

Data were retrospectively collected from 69 Brazilian patients (45 boys) with growth hormone deficiency (GHD) who received exogenous growth hormone (GH) for a median duration of 4 years (range 1-13 years). Forty-two patients had multiple pituitary hormone deficiencies and 27 had isolated GHD. Peak GH was <7 ng/ml (IRMA) or <3.2 ng/ml (IFMA) after two stimulation tests.. Therapy was started at median age of 10.0 years (range 2.2-21.6 years), bone age of 5.8 years (0.5-13.5 years) and height standard deviation score -4.4 (range -9.3 to -1.6). MRI revealed pituitary abnormalities in 87% of patients. Homozygous mutations in PROP-1, GHRH-R, GH-1 or HESX-1 genes were found in 12 patients. Mean height velocities were 3.3 pretreatment and 10.3, 7.8, 7.4 and 6.4 cm/yr, respectively, during 1-4 years of treatment with GH. In conclusion, the high prevalence (96%) of genetic and/or pituitary abnormalities probably reflects the stringent diagnostic criteria used, and GH replacement resulted in significant catch-up growth.

Proton spectroscopy in Alzheimer`s disease and cognitive impairment no dementia: A community-based study

Objective: To describe the findings of proton magnetic resonance spectroscopy (H-1-MRS) in Alzheimer`s disease (AD) and cognitive impairment, no dementia (CIND) elderly from a community-based sample. Methods: Thirteen patients with AD, 12 with CIND and 15 normal individuals were evaluated. The H-1-MRS was performed in the right temporal, left parietal and medial occipital regions studying the metabolites N-acetylaspartate (NAA), creatine (Cr), choline (Cho) and myoinositol (ml). The clinical diagnosis was based on standardized cognitive tests - MMSE and CAMDEX - and the results correlated with the H-1-MRS. Results: Parietal Cho was higher in control individuals and lower in CIND subjects. AD and control groups were better identified by temporal and parietal ml combined with the temporal NAA/Cr ratio. CIND was better identified by parietal Cho. Conclusion: The H-1-MRS findings confirmed the hypothesis that metabolic alterations are present since the first symptoms of cognitively impaired elderly subjects. These results suggest that combining MRS from different cerebral regions can help in the diagnosis and follow-up of community elderly individuals with memory complaints and AD. Copyright (C) 2008 S. Karger AG, Basel.

Magnetic Resonance Imaging Assessment of Subchondral Bone and Soft Tissues in Knee Osteoarthritis

Knee osteoarthritis (OA) has to be considered a whole joint disease. Magnetic resonance imaging (MRI) allows superior assessment of all joint tissues that may be involved in OA, such as the subchondral bone, synovium, ligaments, and periarticular soft tissues. Reliable MRI-based scoring systems are available to assess and quantify these structures and associated pathology. Cross-sectional and longitudinal evaluation has enabled practitioners to understand their relevance in explaining pain and structural progression.

Lower Extremities Magnetic Resonance Angiography With Blood Pressure Cuff Compression: Quantitative Dynamic Analysis

Purpose: To quantitatively evaluate changes induced by the application of a femoral blood-pressure cuff (BPC) on run-off magnetic resonance angiography (MRA). which is a method generally previously proposed to reduce venous contamination in the leg. Materials and Methods: This study was Health Insurance Portability and Accountability Act (HIPAA)- and Institutional Review Board (IRB)-compliant, We used time-resolved gradient-echo gadolinium (Gd)-enhanced MRA to measure BPC effects on arterial, venous, and soft-tissue enhancement. Seven healthy volunteers (six men) were studied with the BPC applied at the mid-femoral level unilaterally using a 1.5T MR system after intravenous injection of Gd-BOPTA. Different statistical tools were used such as the Wilcoxon signed rank test and a cubic smoothing spline fit. Results: We found that BPC application induces delayed venous filling (as previously described), but also induces significant decreases in arterial inflow, arterial enhancement, vascular-soft tissue contrast, and delayed peak enhancement (which have not been previously measured). Conclusion: The potential benefits from using a BPC for run-off MRA must be balanced against the potential pitfalls, elucidated by our findings.

Magnetic Resonance Imaging in Knee Osteoarthritis Research: Semiquantitative and Compositional Assessment

Semiquantitative assessment of the knee by expert magnetic resonance imaging readers is a powerful research tool for understanding the natural history of osteoarthritis (OA). Several reliable semiquantitative scoring systems have been applied to large observational cross-sectional and longitudinal epidemiologic studies and interventional clinical trials. Such evaluations have enabled understanding of the relevance of disease in structures within the knee joint to explain pain and progression of OA. Compositional imaging of cartilage has added to our ability to detect early degeneration before morphologic changes are present, which may help to prevent the permanent morphologic changes commonly seen in knee OA.

Magnetic Resonance Angiography in Extracranial Giant Cell Arteritis

Background: Noninvasive diagnosis of giant cell arteritis (GCA) remains challenging, particularly with regard to evaluation of extracranial arterial disease. Objectives: The objective of the study was to retrospectively review extracranial involvement in patients with GCA and/or polymyalgia rheumatica (PMR), evaluated with magnetic resonance imaging (MRI), especially 3-dimensional contrast-enhanced magnetic resonance angiography images of the aortic arch and its branches. Methods: Clinical information, biopsy status, and MRI examinations of 28 patients with GCA/PMR were reviewed. Patient images were mixed randomly with 20 normal control images and were independently reviewed by 2 radiologists. Interobserver agreement for detection of arterial stenosis was determined by the k coefficient. Results: Both readers described vascular alterations in keeping with extracranial GCA in 19 of 28 patients (67%) with good interobserver agreement (k = 0.73) and with even higher agreement on diagnosing nonocclusive versus occlusive disease (k = 1.00). The most common lesions were bilateral axillary stenosis or obstructions, observed by both readers in 8 patients (28%). Among the 19 patients with magnetic resonance angiography lesions in the subclavian/axillary arteries, 12 (75%) had biopsy-proven GCA, but only 5 (41%) of these patients had clinical features of large artery disease. Conclusions: In our series review, MRI could provide accurate information on involvement of the aortic arch and its branches in extracranial GCA, depicting different degrees of stenosis. Our analysis also illustrates that occult large artery vasculitis should be considered in patients without biopsy-proven GCA, patients with classic GCA but without clinical signs of large artery disease, and in patients initially diagnosed as having PMR.

Magnetic resonance imaging quantification of regional cerebral blood flow and cerebrovascular reactivity to carbon dioxide in normotensive and hypertensive rats

Hypertension afflicts 25% of the general population and over 50% of the elderly. In the present work, arterial spin labeling MRI was used to non-invasively quantify regional cerebral blood flow (CBE), cerebrovascular resistance and CO(2) reactivity in spontaneously hypertensive rats (SHR) and in normotensive Wistar Kyoto rats (WKY), at two different ages (3 months and 10 months) and under the effects of two anesthetics, alpha-chloralose and 2% isoflurane (1.5 MAC). Repeated CBE measurements were highly consistent, differing by less than 10% and 18% within and across animals, respectively. Under alpha-chloralose, whole brain CBE at normocapnia did not differ between groups (young WKY: 61 3 ml/100 g/min; adult WKY: 62 +/- 4 ml/100 g/min; young SHR: 70 +/- 9 ml/100 g/min: adult SHR: 69 8 ml/100 g/min), indicating normal cerebral autoregulation in SHR. At hypercapnia, CBE values increased significantly, and a linear relationship between CBE and PaCO(2) levels was observed. In contrast, 2% isoflurane impaired cerebral autoregulation. Whole brain CBE in SHR was significantly higher than in WKY rats at normocapnia (young SHR: 139 +/- 25 ml/100 g/min; adult SHR: 104 +/- 23 ml/100 g/min; young WKY: 55 +/- 9 ml/100 g/min; adult WKY: 71 +/- 19 ml/100 g/min). CBE values increased significantly with increasing CO(2): however, there was a clear saturation of CBF at PaCO(2) levels greater than 70 mm Hg in both young and adult rats, regardless of absolute CBE values, suggesting that isoflurane interferes with the vasoclilatory mechanisms of CO(2). This behavior was observed for both cortical and subcortical structures. Under either anesthetic, CO(2) reactivity values in adult SHR were decreased, confirming that hypertension, when combined with age, increases cerebrovascular resistance and reduces cerebrovascular compliance. Published by Elsevier Inc.

Evaluation of the lateral pterygoid muscle using magnetic resonance imaging

Objectives: The aims of this study were to evaluate the visibility of the lateral pterygoid muscle (LPM) in temporomandibular joint (TMJ) images obtained by MRI, using different projections and to compare image findings with clinical symptoms of patients with and without temporomandibular disorders (TMD). Methods: In this study, LPM images of 50 participants with and without TMDs were investigated by MRI. The images of the LPM in different projections of 100 TMJs from 35 participants (70 TMJs) with and 15 participants (30 TMJs) without clinical signs and symptoms of TMD were visible and analysed. Results: The oblique sagittal and axial images of the TMJ clearly showed the LPM. Hypertrophy (1.45%), atrophy (2.85%) and contracture (2.85%) were the abnormalities found in the LPM. TMD signs, such as hypermobility (11.4%), hypomobility (12.9%) and disc displacement (20.0%), could be seen in TMJ images. Related clinical symptoms, such as pain (71.4%), articular sounds (30.4%), bruxism (25.7%) and headache (22.9%), were observed. Conclusions: Patients with TMD can present with alterations in the LPM thickness. Patients without TMD also showed alterations, such as atrophy and contracture, in TMJ images. Recognition of alterations in the LPM will improve our understanding of clinical symptoms and pathophysiology of TMD, and may lead to a more specific diagnosis of these disorders. Dentomaxillofacial Radiology (2010) 39, 494-500. doi: 10.1259/dmfr/80928433

A novel target-field method for finite-length magnetic resonance shim coils: I. Zonal shims

This paper presents a new approach for the design of genuinely finite-length shim and gradient coils, intended for use in magnetic resonance imaging equipment. A cylindrical target region is located asymmetrically, at an arbitrary position within a coil of finite length. A desired target field is specified on the surface of that region, and a method is given that enables winding patterns on the surface of the coil to be designed, to produce the desired field at the inner target region. The method uses a minimization technique combined with regularization, to find the current density on the surface of the coil. The method is illustrated for linear, quadratic and cubic magnetic target fields located asymmetrically within a finite-length coil.

Asymmetric zonal shim coils for magnetic resonance applications

A method is presented for the systematic design of asymmetric zonal shim coils for magnetic resonance applications. Fourier-series methods are used to represent the magnetic field inside and outside a circular cylinder of length 2L and radius a. The current density on the cylinder is also represented using Fourier series. Any desired field can be specified in advance on the cylinder's radius, over some nonsymmetric portion pL