Previous Magnetic Resonance Imaging Research Articles

Brain structures in pediatric maltreatment-related posttraumatic stress disorder: a sociodemographically matched study

Background Previous investigations suggest that maltreated children evidence alterations of chemical mediators of stress and adverse brain development. Previous anatomical magnetic resonance imaging (MRI) brain studies have not controlled for socioeconomic status. Methods In this study, 28 psychotropic naïve children and adolescents with maltreatment-related posttraumatic stress disorder (PTSD) and 66 sociodemographically similar healthy control subjects underwent comprehensive clinical assessments and anatomical MRI brain scans. Results Compared with control subjects, subjects with PTSD had smaller intracranial, cerebral, and prefrontal cortex, prefrontal cortical white matter, and right temporal lobe volumes and areas of the corpus callosum and its subregions (2, 4, 5, 6, and 7), and larger frontal lobe cerebrospinal fluid (CSF) volumes than control subjects. The total midsagittal area of corpus callosum and middle and posterior regions remained smaller in subjects with PTSD, whereas right, left, and total lateral ventricles and frontal lobe CSF were proportionally larger than in control subjects, after adjustment for cerebral volume. Brain volumes positively correlated with age of onset of PTSD trauma and negatively correlated with duration of abuse. Significant gender × group effect demonstrated greater lateral ventricular volume increases in maltreated male subjects with PTSD than maltreated female subjects with PTSD. No hippocampal differences were seen. Conclusions These data provide further evidence to suggest that maltreatment-related PTSD is associated with adverse brain development. These data also suggest that male children may be more vulnerable to these effects.

Regional prefrontal gray and white matter abnormalities in bipolar disorder

Background: Previous magnetic resonance imaging (MRI) studies indicate that compared with healthy volunteers, patients with bipolar disorder have structural and functional abnormalities in the prefrontal cortex. The aim of this study was to investigate differences in prefrontal subregions between bipolar patients and healthy subjects. Methods: Bipolar patients hospitalized for a manic episode ( n = 17), and demographically matched healthy volunteers ( n = 12) were recruited. Contiguous 1-mm coronal T1-weighted MRI slices were obtained using a Picker 1.5 Tesla scanner. The gray and white matter volumes of five prefrontal subregions of interest were measured: superior, middle, inferior, cingulate, and orbital. Results: Bipolar patients had smaller left prefrontal gray matter volumes, specifically in the middle and superior subregions and smaller right prefrontal gray matter volumes, specifically in the inferior and middle subregions. White matter differences were not observed in any of the prefrontal subregions. Conclusions: The results suggest that bipolar patients have subregion-specific gray matter volume reductions in the prefrontal cortex as compared to healthy subjects. Further investigations into the role of specific prefrontal subregions in bipolar disorder are warranted.

Reduced hippocampal volume and total white matter volume in posttraumatic stress disorder

Background: Reduced hippocampal volumes in posttraumatic stress disorder (PTSD) patients are thought to reflect specific changes of this structure. Previous magnetic resonance imaging (MRI) studies have not consistently examined indices of overall brain atrophy, therefore it cannot be completely ruled out that hippocampal changes are explained by whole-brain atrophy. The purpose of this study was to assess hippocampal and whole-brain volume in civilian PTSD. Methods: Twelve subjects with PTSD and 10 control subjects underwent brain MRI. Hippocampal volumes were visually quantified using a computerized volumetric program. Whole-brain volumes were obtained with automated k-means-based segmentation. Results: No differences were found in intracranial volumes (ICV). Subjects with PTSD had higher cerebrospinal fluid (CSF)/ICV ratios and lower white matter/ICV ratios, consistent with generalized white matter (WM) atrophy. The effect of age on CSF/ICV was more pronounced in the PTSD group. Subjects with PTSD had smaller absolute and normalized bilateral hippocampal volumes. These differences persisted after adjusting for lifetime weeks of alcohol intoxication. Posttraumatic stress disorder and depression scores correlated negatively with left hippocampal volume, but PTSD scores were a better predictor of hippocampal volumes. Conclusions: Our results replicate previous findings of reduced hippocampal volume in PTSD but also suggest independent, generalized, white matter atrophy.

Intra-voxel and inter-voxel coherence in patients with multiple sclerosis assessed using diffusion tensor MRI.

Previous diffusion tensor magnetic resonance imaging (DT-MRI) studies reported mean diffusivity () and fractional anisotropy (FA) changes in lesions and normal-appearing white matter (NAWM) of patients with multiple sclerosis (MS), but neglected the additional information which can be obtained by the analysis of the inter-voxel coherence (C). The present study is based on a large sample of patients with MS and it is aimed at assessing the potential role of C in the quantification of MS-related tissue damage of T2-visible lesions and NAWM. We obtained dual-echo, T1-weighted and DT-MRI scans from 78 patients with relapsing-remitting (RR), secondary progressive (SP), or primary progressive (PP) MS and from 26 healthy volunteers. We calculated, FA and C of T2-hyperintense lesions, T1-isointense lesions, T1-hypointense lesions and several areas of the NAWM. and FA of the majority of NAWM regions studied from MS patients were different from the corresponding quantities of the white matter from controls. NAWM C from patients was lower than white matter C from controls only for the parietal pericallosal areas. SPMS patients had higher corpus callosum and lower corpus callosum FA and C than patients with either RRMS or PPMS. Average lesion was higher, and average FA and C lower than the corresponding quantities measured in the NAWM. Average T1-hypointense lesion was higher and average FA lower than the corresponding quantities of T1-isointense lesions, whereas average C of these two lesion populations were not different. SPMS had higher average lesion than both PPMS and RRMS patients. NAWM and C of the corpus callosum were moderately correlated with disability. This study confirms the role of DT-MRI metrics to identify MS lesions with different amounts of tissue damage and to detect diffuse changes in the NAWM. It also shows that measuring C enables us to obtain additional information about tissue damage, which is complementary to that given by the analysis of and FA.

System for automated magnetic resonance imaging of a superheated emulsion chamber for brachytherapy dosimetry

This manuscript describes a pressure cycling and brachytherapy source insertion/removal system developed to automate magnetic resonance imaging (MRI) of a superheated emulsion chamber (SEC), a position-sensitive radiation dosimeter. Previous MRI studies of a SEC demonstrated its efficacy for obtaining two-dimensional relative radiation dose profiles from brachytherapy sources. The SEC detector is a 0.5 l chamber containing an emulsion of highly superheated halocarbon droplets suspended in a tissue-equivalent glycerin-based gel. When irradiated by a source, the halocarbon droplets vaporize into microbubbles. Relative dose profiles are determined by mapping, via MRI, the resulting microbubble distributions. During use the SEC is repeatedly cycled through a series of steps including source insertion, exposure, and source removal, MRI data collection, and chamber pressurization and depressurization. To acquire microbubble counts sufficient to derive dose profiles having good statistics, it is necessary to collect hundreds of MRI data sets as the SEC is cycled. Clearly, automation of SEC cycling is essential for its practical use as a radiation dosimeter. The operations required to use the SEC as a radiation dosimeter have been fully automated on a commercial 3.0 T MRI scanner. The hardware and software developed to achieve automated cycling of a SEC are described. Microbubble distributions and calculated microbubble density maps generated from MRI data collected while cycling a SEC are presented to demonstrate the utility of the automated system.

Abuse Said to Interfere With Child Brain Development

Abuse Said to Interfere With Child Brain Development

Decreased hippocampal N-acetylaspartate in the absence of atrophy in posttraumatic stress disorder

Background: Previous magnetic resonance imaging studies of posttraumatic stress disorder reported hippocampal volume loss. The goals of this study were 1) to determine the relationship between hippocampal atrophy and posttraumatic stress disorder in the absence of alcohol abuse, and 2) to test if loss of N-acetylaspartate (a neuron marker) in the hippocampus of posttraumatic stress disorder occurs separate from atrophy. In addition, volume changes in the entorhinal cortex were also explored. Methods: Eighteen male patients with combat-related posttraumatic stress disorder (mean age 51.2 ± 2.5 years) and 19 male control subjects (mean age 51.8 ± 3.2 years) were studied using magnetic resonance imaging and Proton magnetic resonance spectroscopic imaging. Both groups had no alcohol and drug abuse during the past 5 years. Results: Posttraumatic stress disorder and control subjects had similar volumes of hippocampus and entorhinal cortex. In contrast to volume, N-acetylaspartate was significantly reduced by about 23% bilaterally in the hippocampus of posttraumatic stress disorder when compared with control subjects, and creatine-containing compounds were reduced by 26% in the right hippocampus of posttraumatic stress disorder. Conclusions: N-acetyl asparate and creatine reductions imply that there are hippocampal abnormalities in posttraumatic stress disorder. Furthermore, these metabolite changes seem to be better indicators of posttraumatic stress disorder pathology than volume losses.

An MRI study of temporal lobe abnormalities and negative symptoms in chronic schizophrenia

Previous magnetic resonance imaging (MRI) studies have reported various subtle brain abnormalities in schizophrenic patients, including temporal lobe abnormalities, which are of particular interest given the role of this brain region in auditory and language processing, and the characteristic deficits in these processes in schizophrenia . Subjects in this study were 16 male patients diagnosed with chronic schizophrenia and 15 healthy male comparison subjects. These patients were characterized by negative symptoms. High spatial resolution coronal MRI 1.5-mm-thick slices were used to measure the gray matter volume of the superior temporal gyrus, anterior and posterior amygdala/hippocampal complex, and parahippocampal gyrus. Patients, relative to normal comparison subjects, evinced a reduction of gray matter volume in bilateral superior temporal gyri and anterior amygdala/hippocampal complex. The reduction in gray matter of the superior temporal gyrus in patients with schizophrenia is consistent with previous findings, and is noteworthy in that it was found in this group of patients with predominantly negative symptoms. The reduction in the anterior amygdala/hippocampal complex was an additional temporal lobe finding. These results underscore the role of temporal lobe structures in the pathophysiology of schizophrenia.

Magnetic resonance imaging findings of vascular malformations of the lower extremity.

Vascular malformations are congenital lesions resulting from a defect during embryogenesis. Magnetic resonance imaging (MRI) is a very effective method for demonstrating detailed information regarding involved structures, extent, and flow characteristics of vascular malformations. In previous MRI studies, most of the emphasis is laid on the difference between high- and low-flow lesions, whereas little detailed information is available about the extent of local tissue involvement. These additional characteristics may influence the approach in treating these malformations and improve understanding of the pathogenesis. We retrospectively reviewed MRI scans of 40 patients with vascular malformations of the lower extremity. Thirty-four patients had low-flow lesions, and six had high-flow lesions. Of the low-flow lesions, 23 patients (67.6 percent) had muscle infiltration, with four of the six high-flow lesions having muscle infiltration. Nine of the 11 male patients (81.8 percent) with low-flow lesions had associated muscle infiltration, in comparison with 14 of the 23 female patients (60.9 percent) with low-flow lesions (p = 0.206). Eighty percent of the vascular malformations located on the thigh with muscle involvement had involvement of the anterior muscle group, whereas 86.6 percent of the patients with a vascular malformation located on the leg and with associated muscle involvement had at least the posterior muscle group involved (p = 0.0049). Ten patients (25 percent) of the whole group had bone infiltration. Low-flow lesions often had multifocal lesions (20.6 percent), whereas associated muscle atrophy was visible in 10 low-flow lesions and in two high-flow lesions. In low-flow lesions with muscle infiltration (n = 23), 43 percent (n = 10) had associated surrounding muscle atrophy (p = 0.009). Hypertrophy of the subcutaneous tissue was visible in 11 low-flow patients (32.4 percent). The high amount of muscle and bone involvement in vascular malformations of the lower extremity is emphasized with this study. Of particular interest was the difference in affected muscle groups. The angiosome concept is used to explain this preponderance, and we feel the angiosome concept could also be used when assessing possible intervention. The surrounding muscle atrophy and multifocal nature of these anomalies are further important considerations when assessing the possibility of intervention.

PUBOPERINEALES: MUSCULAR BOUNDARIES OF THE MALE UROGENITAL HIATUS IN 3D FROM MAGNETIC RESONANCE IMAGING

The aims of this report are 1) to extend our previous two-dimensional magnetic resonance imaging study to create a three-dimensional image of the pelvic floor, including the puboperinealis, the most anteromedial component of the levator ani; 2) to clarify the historical controversy about this particular component of the levator ani; and 3) to present clinical implications of this muscle with respect to urinary continence and radical prostatectomy. We reused the axial magnetic resonance imaging series from 1 of 15 men in a previous series. Analyze AVWTM allowed creation of three-dimensional images. Further, a movie clip of all three-dimensional images was developed and placed at the manuscript-dedicated Web site: http://www.mayo. edu/ppmovie/pp.html. Our three-dimensional images show how the puboperinealis portion of the levator ani flanks the urethra as it courses from the pubis to its insertion in the perineal body. The puboperinealis corresponds to muscles previously designated as the levator prostatae, Wilson's muscle, pubourethralis, and levator urethrae, among others. The images suggest that the puboperinealis is the muscle most responsible for the quick stop phenomenon of urination in the male. Our study supports the suggestion that weakening of the puboperinealis by transection, traction injury, or denervation may affect urinary continence after radical prostatectomy.

Coronary artery calcification in older adults with minimal clinical or subclinical cardiovascular disease.

Coronary artery calcification (CAC) reflects the extent of coronary artery atherosclerosis. The extent of coronary artery calcification is not well described in older adults. To determine the extent of CAC in older adults participating in a large population study of cardiovascular disease (CVD), especially those characterized as having minimal clinical or subclinical cardiovascular disease. An observational epidemiologic study. Participants in the Cardiovascular Health Study Cohort, mean age 78 years, who had electron beam computed tomography (EBT) scan of the heart (n = 133); included were 106 persons with no prior evidence of clinical or subclinical CVD. Total CAC score was measured using cardiac EBT. Cardiovascular disease and risk factors, as well as carotid ultrasound, electrocardiogram, echocardiogram, and ankle-arm index, had been measured previously to define subclinical disease. Previous cerebral magnetic resonance imaging was also evaluated. Overall, the CAC scores were higher in those with clinical cardiovascular disease or evidence of subclinical cardiovascular disease than in those with no evidence of disease. For the 106 participants without evidence of clinical or subclinical disease, the median score was 176, compared with 367 in those with subclinical disease and 923 in those with clinical CVD. Seventeen persons had scores of zero. There was little difference in risk factors across quartiles of CAC in the subgroup of 106 with prior characterization of minimal CVD despite the broad range of CAC scores. There was a higher proportion of those with white matter grade > or = 2 by magnetic resonance imaging among those with higher CAC scores (P = .025). Infarct-like lesions prevalence ranged from 12.5% in the lowest group to 47.1% in the highest CAC group (P = .019). Older adults with evidence of clinical or subclinical CVD have higher total CAC scores. Though the extent of coronary artery calcification was lower in those with minimal evidence of CVD, the range was broad and not explained by CVD risk factors.

Conflicting MRI signals from gliosis and neuronal vacuolation in prion diseases.

Magnetic resonance imaging (MRI) has given inconsistent results when used as a non-invasive diagnostic tool for Creutzfeldt-Jakob disease (CJD). In order to understand this finding, we studied a hamster model of scrapie by in vivo MRI and histopathology. Vacuolation of neurones/neuropil and gliosis were found to correlate with hypo-intense and hyper-intense changes in the conventional T2-weighted MR images, respectively. These opposing effects were shown to give rise to normal images of a scrapie-affected brain undergoing severe neurodegeneration, and may underlie the variability of previous CJD MRI data.

Toward Understanding the Neuronal Pathogenesis of Aspartylglucosaminuria: Expression of Aspartylglucosaminidase in Brain during Development

The deficiency of a lysosomal enzyme, aspartylglucosaminidase, results in a lysosomal storage disorder, aspartylglucosaminuria, manifesting as progressive mental retardation. To understand tissue pathogenesis and disease progression we analyzed the developmental expression of the enzyme, especially in brain, which is the major source of the pathological symptoms. Highest mRNA levels in brain were detected during embryogenesis, the levels decreased neonatally and started to increase again from Day 7 on. In Western analyses, a defective processing of aspartylglucosaminidase was observed in brain as compared to other tissues, resulting in very low levels of the mature, active form of the enzyme. Interestingly immunohistochemical analyses of mouse brain revealed that aspartylglucosaminidase immunoreactivity closely mimicked the myelin basic protein immunostaining pattern. The only evident neuronal staining was observed in the developing Purkinje cells of the cerebellum from Days 3 to 10, reflecting well the mRNA expression. In human infant brain, the immunostaining was also present in myelinated fibers as well as in the Purkinje cells and, additionally, in the soma and extensions of other neurons. In the adult human brain neurons and oligodendrocytes displayed immunoreactivity whereas myelinated fibers were not stained. Our results of aspartylglucosaminidase immunostaining in myelinated fibers of infant brain might imply the involvement of aspartylglucosaminidase in the early myelination process. This is consistent with previous magnetic resonance imaging findings in the brains of aspartylglucosaminuria patients, revealing delayed myelination in childhood.

Hypnosis Using a Communication Device to Increase Magnetic Resonance Imaging Tolerance with a Claustrophobic Patient

This is a case report of a patient who prematurely terminated two previous magnetic resonance imaging procedures because of his highly claustrophobic condition. The patient was induced into a hypnotic trance twice before his third magnetic resonance imaging examination and he was given posthypnotic suggestions for decreased anxiety and increased physiologic control. Using a communication device with headphones on the patient, he was induced into a trance as he entered the magnet. This patient was successfully able to cope with this procedure and reported great satisfaction with treatment.

Endoscopic removal of a third ventricular cysticercal cyst

We report the case of a young man who presented with acute obstructive hydrocephalus previously treated with bilateral ventriculo-peritoneal shunts. Previous magnetic resonance imaging studies were consistent with aqueduct stenosis; no intraventricular pathology was identified. Neuroendoscopy was performed in order to explore the third ventricle and perform a third ventriculostomy. This revealed a cysticercal lesion of the third ventricle which was removed endoscopically. In addition, a third ventriculostomy was performed and both shunt systems removed. Following a course of albendazole the patient went on to make a full recovery, and currently remains shunt independent.

Magnetic resonance imaging evaluation of photodynamic therapy-induced hemorrhagic necrosis in the murine M1 tumor model.

Proton magnetic resonance imaging (MRI) and histological methods were used to evaluate photodynamic therapy (PDT)-induced hemorrhagic necrosis in the murine M1 tumor within 72 h of treatment of male DBA/2 mice. The effects of three photosensitizing drugs were investigated: Photofrin (n = 4), Zn (II) phthalocyanine (n = 7) and benzoporphyrin derivative monoacid ring A (n = 11). As noted in previous studies of PDT using MRI, MRI makes possible serial, noninvasive, in vivo observation of tissue response to PDT. Our serial study of MRI and histological data confirms that tumors responded in the same way to PDT treatment using the three photosensitizing drugs: vascular damage followed by hemorrhagic necrosis. Most importantly and unlike previous MRI studies of PDT, we used a very high field magnet that enhanced the effect of magnetic susceptibility on image signal when blood is processed by the body after PDT-induced hemorrhagic necrosis. This last finding demonstrates the utility of high field magnets and the importance of localized, serial experiments in future magnetic resonance studies of PDT.

A longitudinal magnetic resonance imaging study of brain changes in adolescents with anorexia nervosa.

To assess whether the cerebral gray and white matter volume deficits described in patients with anorexia nervosa (AN) are fully reversible with weight rehabilitation. A prospective cohort study using magnetic resonance imaging to examine the brains of female adolescents after weight recovery from AN. An adolescent eating disorder program located in a tertiary care children's hospital. Of 13 patients who underwent a previous magnetic resonance imaging study at a low weight, 6 patients were weight recovered and underwent rescanning. All brain measures were corrected for the effects of intracranial volume and age, based on a regression analysis of a group of 34 healthy female control subjects. Scans from the patients with AN were also compared with scans from an age-matched subset of 16 healthy female controls. White matter volumes, gray matter volumes, and cerebrospinal fluid volumes in the weight-recovered AN group. Quantitative analysis showed that white matter and ventricular cerebrospinal fluid volumes changed significantly (P = .03 for both) on weight recovery from AN. The weight-recovered patients had significant gray matter volume deficits (P = .01) and elevated cerebrospinal fluid volumes (P = .005) compared with those of the age-matched controls. They no longer had significant (P = .30) white matter volume deficits. The finding of persistent gray matter volume deficits in patients who have recovered their weight after AN suggests an irreversible component to the structural brain changes associated with AN, in addition to a component that resolves on weight recovery.

MRI and cognitive correlates in schizotypal personality disorder

Increased total brain volume (TBV) has been reported for children with autism spectrum disorder (ASD) but studies in older ASD subjects have been contradictory. Similarly, studies of corpus callosum (CC) area in ASD differ with regard to inclusion criteria, age, and IQ.In the present study, TBV, gray matter (GM), and white matter (WM) volume as well as midsagittal CC area were compared between 15 medication-naïve, high-functioning adolescent and young adult ASD subjects and 15 healthy control individuals, and correlations with visuomotor coordination and imitation abilities were explored. In addition, computational surface-based methods were implemented to encode callosal thickness at high spatial resolution.Total brain volume, GM, and WM were increased and CC area was decreased in ASD subjects, a finding that was predominantly due to ASD subjects with lower IQ. Positive correlations of IQ with volume measures were observed only in control subjects. Autism spectrum disorder subjects showed reduced thickness in the posterior part of the CC. White matter volume showed a trend for negative correlation with dynamic balance and imitation abilities across groups.This study replicates previous structural magnetic resonance imaging (MRI) findings in ASD, emphasizes the role of IQ differences, and adds some evidence for functional implications of structural findings.

Confirmation of reduced temporal limbic structure volume on magnetic resonance imaging in male patients with schizophrenia

A structural deficit in the temporal lobes has been implicated in the pathogenesis of schizophrenia. A prospective magnetic resonance imaging (MRI) study was carried out in 20 young male patients with schizophrenia and 20 agematched healthy male volunteers. Volumetric measurements were performed in all slices with temporal lobe crosssections from the temporal pole to the tip of the Sylvian fissure. Volumetric assessment included the temporal lobe as a whole, hippocampal formation and amygdala complex, temporal horn and cella media of the lateral ventricle, the third ventricle, and hemispheric volume in all slices that showed temporolimbic structures. Brain structural deficit in the patients was most conspicuous in the posterior portion of the hippocampal formation. Significant effects of diagnosis were also found for the total temporal lobe and the third ventricle. Multiple regression analysis revealed posterior hippocampal volume to be significantly determined by diagnosis, but not by age or by temporal lobe or hemispheric volume. Significant correlations of morphologic and clinical parameters were restricted to negative correlations of temporal lobe volume with the global rating and sum score of the Scale for the Assessment of Negative Symptoms. The study confirms subtle temporolimbic deficit reported in previous MRI studies in patients with schizophrenia.

Relationship between Alcohol Withdrawal Seizures and Temporal Lobe White Matter Volume Deficits

A previous magnetic resonance imaging study from our laboratory reported significant temporal lobe volume deficits in cortical gray matter, white matter, and anterior hippocampus in chronic alcoholic men relative to controls. In the present study, we reexamined these data and asked whether withdrawal seizure history was predictive of either the hippocampal or the extrahippocampal volume deficits. A review of the medical charts indicated that 11 alcoholics had experienced one or more alcohol-related seizures and 35 were seizure-free; no patient had a seizure disorder unrelated to alcohol. The two alcoholic groups did not differ significantly in age, education, alcohol consumption variables, premorbid intelligence, Memory Quotient, Trail Making, or detection of hidden figures. Although each alcoholic group showed significant bilateral volume deficits of the anterior hippocampus and frontal-parietal and temporal gray matter, relative to controls, the seizure group had significantly smaller temporal lobe white matter volumes than either the control or the seizure-free groups; the latter two groups did not differ from each other. Both alcoholic groups, however, had white matter volume deficits in the frontal-parietal region. Thus, the seizure group accounted for the white matter volume deficits in the temporal lobe previously reported in the full sample of alcoholics. It seems, then, that reduced white matter volume in the temporal lobes may be either a risk factor for or sequela of alcohol withdrawal seizures.