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PubMed2005

Neuroimaging in neuropsychiatry.

Once limited to structural imaging modalities such as CT and MRI,radiographic evaluation of the psychiatric patient now includes more sophisticated functional techniques such as fMRI, MR spectroscopy, and PET. With the increased sensitivity that these new tools bring comes greater complexity. As new imaging techniques continue to transition from research to clinical application, the imaging options and associated complexity will increase. Consultation with neuroradiology colleagues will allow the practicing psychiatrist to evaluate their patients optimally. These techniques will continue to provide insight into the pathophysiology, etiology, diagnosis, treatment, and prognosis of these patients.

Brain↗
PubMed2004

Smaller subcortical volumes and cognitive deficits in children with prenatal methamphetamine exposure.

The purpose of this pilot study was to examine possible neurotoxic effects of prenatal methamphetamine (Meth) exposure on the developing brain and on cognition. Meth-exposed children (n=13) and unexposed control subjects (n=15) were evaluated with MRI. Global brain volumes and regional brain structures were quantified. Ten Meth-exposed and nine unexposed children also completed neurocognitive assessments. Meth-exposed children scored lower on measures of visual motor integration, attention, verbal memory and long-term spatial memory. There were no differences among the groups in motor skills, short delay spatial memory or measures of non-verbal intelligence. Despite comparable whole brain volumes in each group, the Meth-exposed children had smaller putamen bilaterally (-17.7%), smaller globus pallidus (left: -27%, right: 30%), smaller hippocampus volumes (left: -19%, right: -20%) and a trend for a smaller caudate bilaterally (-13%). The reduction in these brain structures correlated with poorer performance on sustained attention and delayed verbal memory. No group differences in volumes were noted in the thalamus, midbrain or the cerebellum. In summary, compared with the control group, children exposed to Meth prenatally exhibit smaller subcortical volumes and associated neurocognitive deficits. These preliminary findings suggest prenatal Meth exposure may be neurotoxic to the developing brain.

Adolescent↗
PubMed2006

The fornix and mammillary bodies in older adults with Alzheimer's disease, mild cognitive impairment, and cognitive complaints: a volumetric MRI study.

The fornix and mammillary bodies are important limbic structures that have not been systematically investigated in the earliest stages of preclinical dementia. The present study examined volumetric changes in the fornix and mammillary bodies and improved previously established tracing guidelines to increase reliability and provide more comprehensive measurements. Volumetric measurements were made in euthymic older adults, including 16 patients with mild Alzheimer's disease (AD), 20 patients with amnestic mild cognitive impairment (MCI), 20 individuals with cognitive complaints (CC) but normal neuropsychological test performance, and 20 demographically matched healthy controls (HC). Structural magnetic resonance imaging included a T1-weighted 1.5-mm coronal volume, acquired on a GE 1.5T LX scanner. After adjustment for total intracranial volume (ICV), significant volume reductions were observed in the fornix and mammillary bodies in patients with AD as compared with HC, CC, and MCI participants. No volume differences were seen between the HC, CC, and MCI groups. Study findings are consistent with previous research showing volume decreases of the fornix and mammillary bodies in AD, and provide new data on the relative preservation of these structures in preclinical disease stages. Results suggest that atrophy of the fornix and mammillary bodies becomes apparent at the point of conversion from MCI to AD. Longitudinal assessments are needed to delineate the time course and extent of the observed volumetric changes.

Aged↗
PubMed2005

Mapping brain maturation and cognitive development during adolescence.

Non-invasive mapping of brain structure and function with magnetic resonance imaging (MRI) has opened up unprecedented opportunities for studying the neural substrates underlying cognitive development. There is an emerging consensus of a continuous increase throughout adolescence in the volume of white matter, both global and local. There is less agreement on the meaning of asynchronous age-related decreases in the volume of grey matter in different cortical regions; these might equally represent loss ("pruning") or gain (intra-cortical myelination) of tissue. Functional MRI studies have so far focused mostly on executive functions, such as working memory and behavioural inhibition, with very few addressing questions regarding the maturation of social cognition. Future directions for research in this area are discussed in the context of processing biological motion and matching perceptions and actions.

Adolescent↗
PubMed2003

Measuring morphological parameters of the pelvic floor for finite element modelling purposes.

The goal of this study was to obtain a complete data set needed for studying the complex biomechanical behaviour of the pelvic floor muscles using a computer model based on the finite element (FE) theory. The model should be able to predict the effect of surgical interventions and give insight into the function of pelvic floor muscles. Because there was a lack of any information concerning morphological parameters of the pelvic floor muscle structures, we performed an experimental measurement to uncover those morphological parameters. Geometric parameters as well as muscle parameters of the pelvic floor muscles were measured on an embalmed female cadaver. A three-dimensional (3D) geometric data set of the pelvic floor including muscle fibre directions was obtained using a palpator device. A 3D surface model based on the experimental data, needed for mathematical modelling of the pelvic floor, was created. For all parts of the diaphragma pelvis, the optimal muscle fibre length was determined by laser diffraction measurements of the sarcomere length. In addition, other muscle parameters such as physiological cross-sectional area and total muscle fibre length were determined. Apart from these measurements we obtained a data set of the pelvic floor structures based on nuclear magnetic resonance imaging (MRI) on the same cadaver specimen. The purpose of this experiment was to discover the relationship between the MRI morphology and geometrical parameters obtained from the previous measurements. The produced data set is not only important for biomechanical modelling of the pelvic floor muscles, but it also describes the geometry of muscle fibres and is useful for functional analysis of the pelvic floor in general. By the use of many reference landmarks all these morphologic data concerning fibre directions and optimal fibre length can be morphed to the geometrical data based on segmentation from MRI scans. These data can be directly used as an input for building a mathematical model based on FE theory.

Aged↗
PubMed1999

Incidence of intrahepatic biliary cysts in biliary atresia after hepatic portoenterostomy and associated histopathologic findings in the liver and porta hepatis at diagnosis.

BACKGROUND/PURPOSE: The association of intrahepatic biliary cysts in biliary atresia (BA) after hepatic portoenterostomy has drawn the attention of many pediatric surgeons and has become an important subject in clinical management, but the incidence and causes of this association are not well known. METHODS: During the last 14 years, we operated on 33 BA patients by hepatic portoenterostomy. Five patients could not be followed up over a 1-year period, so the remaining 28 patients had their intrahepatic structure investigated by periodic magnetic resonance imaging (MRI), and were confirmed at autopsy. The authors also reviewed the preoperative conditions of these patients and the histopathologic changes in the liver biopsy and the porta hepatis specimens taken at portoenterostomy. RESULTS: (1) Intrahepatic biliary cysts were found in 6 of the 28 patients studied (21%). Of 16 patients who were operated on after 1989 and are undergoing follow-up by MRI, 4 (25%) had cysts. (2) Five of the 6 patients with cysts had episodes of cholangitis before or at the time of discovery of the cysts, and 4 of them have had their jaundice reappear since the discovery of the cysts. (3) The intralobular spaces (ILS) with fibrosis and the number of bile ducts had increased in the group with cysts compared with those in the group without cysts. (4) The bile duct maximum size in the porta hepatis (PH) was similar in the groups with and without cysts, but a denudation of the mucosal lining cells in the duct, and a fibrosis and inflammation around the duct had increased in the group with cysts compared with those in the group without cysts. (5) Statistically, the fibrosis found in the ILS and the inflammation around the bile duct found in the PH were induced as a correlative factor affecting cyst formation. CONCLUSIONS: The association of intrahepatic biliary cysts in BA after portoenterostomy is frequent. The fibrous change in the ILS and the inflammatory process around the bile ducts might be potential causes of cyst formation.

Bile Ducts↗
PubMed2002

Cerebral grey matter pathology and fatigue in patients with multiple sclerosis: a preliminary study.

In patients with multiple sclerosis (MS), we investigated whether the extent of cerebral grey matter (GM) pathology is associated with the presence and severity of fatigue. We quantified cerebral GM pathology in 28 MS patients (14 with fatigue and 14 without fatigue) using magnetization transfer (MT) and diffusion tensor (DT) magnetic resonance imaging (MRI). The average MT ratio and mean diffusivity from cerebral GM did not differ between fatigued and non-fatigued patients. Fatigued and non-fatigued patients also did not differ in terms of GM pathology of the cerebral cortex of the frontal lobe and basal ganglia. No correlations were found between the fatigue severity scale scores and any of the MT- and DT-MRI quantities. These preliminary results suggest that structural GM pathology is not a major contributing factor to the development of fatigue in patients with MS.

Adult↗
PubMed2005

[Headache from idiopathic cervical artery dissection: time-course and follow-up].

Headache is very common during the acute phase of cervical artery-dissection (CAD) sometimes mimicking a migraine attack. However, the relationships between these two conditions are complex and the course of headache in patients with CAD is not well known. Indeed, migraine is an independent vascular risk factor of stroke, especially ischemic stroke. Recently, a case-control study has shown that migraine is an independent risk factor of CAD. We have studied the course of headache in all consecutive patients hospitalized for spontaneous CAD in our stroke unit between 1998 and 2001, confirmed by a mural hematoma on MRI. We conducted patient interviews with a structured questionnaire about headache (according to the International Headache Society criteria) before and after the CAD. Forty-two patients had had a spontaneous CAD during this period. Twenty-two had had headache in the past: 9 migraine without aura, 5 migraine with aura and 8 with episodic tension-type headache. The headache improved in 22 patients (95.5 percent) after the spontaneous CAD. Of 14 patients who were migrainers, 13 (92 percent) had fewer migraine attacks after the CAD. Only 7 patients, without previous headache developed new headache after CAD: three migraine without aura, three episodic tension-type headache and one chronic tension-type headache. For the majority of patients the pre-existing headache improved after spontaneous CAD. A few patients developed a new headache only after CAD. Relationships between CAD, migraine and elastic tissue disorder should now to be explored.

Cerebral Hemorrhage↗
PubMedDate not supplied

Magnetic resonance imaging around the eustachian tube.

Magnetic resonance imaging (MRI) of the eustachian tube, the nasopharynx, and the middle ear was performed in normal subjects and patients with ear diseases. In normal subjects, the high soft tissue contrast resolution of MRI gave a clearer view of nasopharyngeal structures compared to roentgenologic examinations including computed tomography (CT). Several cases of nasopharyngeal pathology are also presented. Nasopharyngeal carcinoma was excellently depicted, and its margin was clearly visualized. Tumor involvement of the eustachian tube and accompanying otitis media with effusion were clearly visualized. In a patient with submucous cleft palate, abnormal arrangement of levator veli palatini muscles and possible deformity of the eustachian tube cartilage were found. Magnetic resonance imaging is expected to become a valuable tool for the diagnosis of nasopharyngeal and middle ear diseases.

Adolescent↗
PubMed1999

Is the course of brain development in schizophrenia delayed? Evidence from onsets in adolescence.

A degree of ventricular enlargement, together with a reduction of total cortical mass and loss of asymmetry is reported in schizophrenia, but the meaning is obscure. These changes may reflect an anomaly of brain development. Brain structure was assessed on a 1.5-Tesla MRI scan in a series of 29 adolescents at the time of a first episode of schizophrenia and compared with 15 adolescents with other serious psychiatric disturbance (mostly psychotic) and 20 normal adolescent controls. The age at scan ranged between 13 and 20 years. In the adolescents with a diagnosis of schizophrenia, total brain volume increased with age in a way that differed significantly (p=0.007) from that seen in patients with other psychiatric disturbance and normal controls. Thus, brain growth, as assessed by this index, had reached a plateau in the control group by the age of 13 years, but this was not true of patients with schizophrenia. The measure that most clearly distinguished the groups (p<0.001 after co-varying for height and sex) was the volume of the left lateral ventricle the ventricle was significantly larger in patients with schizophrenic illness, and ventricular size increased with age to a greater extent in the patient group, although not significantly so, than in normal controls. Thus, aspects of brain growth are delayed in patients with early onset schizophrenia, and the greatest severity of illness is reflected in a component of growth that is lateralized to the dominant hemisphere. Individuals who develop serious psychiatric illness, including schizophrenia, represent a fraction of the population in whom a component of the relative development of the cerebral hemispheres occurs late.

Adolescent↗
PubMed2005

Brain MRI abnormalities in schizophrenia: same genes or same environment?

BACKGROUND: Structural brain volume abnormalities are among the most extensively studied endophenotypes in schizophrenia. Bivariate genetic model fitting (adjusted to account for selection) was used to quantify the genetic relationship between schizophrenia and brain volumes and to estimate the heritability of these volumes. METHOD: We demonstrated by simulation that the adjusted genetic model produced unbiased estimates for endophenotype heritability and the genetic and environmental correlations. The model was applied to brain volumes (whole brain, hippocampus, third and lateral ventricles) in a sample of 14 monozygotic (MZ) twin pairs concordant for schizophrenia, 10 MZ discordant pairs, 17 MZ control pairs, 22 discordant sibling pairs, three concordant sibling pairs, and 114 healthy control subjects. RESULTS: Whole brain showed a substantial heritability (88%) and lateral ventricles substantial common environmental effects (67%). Whole brain showed a significant genetic correlation with schizophrenia, whereas lateral ventricles showed a significant individual specific correlation with schizophrenia. There were significant familial effects for hippocampus and third ventricle, but the analyses could not resolve whether these were genetic or environmental in origin (around 30%each). CONCLUSIONS: Using genetic model fitting on twin and sibling data we have demonstrated differential sources of covariation between schizophrenia and brain volumes, genetic in the case of whole brain volume and individual specific environment in the case of lateral ventricles.

Adolescent↗
PubMed2004

Presence of normal creatine in the muscle of a patient with a mutation in the creatine transporter: a case study.

To date, more than seven families have been reported who carry a mutation in the X-linked creatine-transporter (CrT) gene. The resulting lack of creatine in the brain is associated with mental retardation, severe expressive language disorder, mild epilepsy, and a complete absence of Cr in the brain (measured using MRS). Conversely, these patients had no observable cardiac or musculo-skeletal deficits. In this case study, a 22-year-old patient underwent surgical repair for scoliosis. Proton MRS of this patient's brain demonstrated the near-absence of creatine and phosphocreatine within the cerebral white and deep gray matter structures. Cerebral atrophy was noted with serial MRI examinations. Subsequent genetic and metabolic analysis showed some biochemical anomalies consistent with a CrT deficiency. The mutation in this patient was identified as a deletion at phenylalanine 107 (delF107). Control muscle biopsies were obtained from archived samples, which had been taken with informed consent during routine muscle biopsies for diagnostic purposes. We determined that the total Cr concentration in the skeletal muscle biopsy was 39.3 +/- 2.94 mmol/kg wet wt., which is not significantly different from non-CrT controls, n = 3 (43.3 +/- 3.57 mmol/kg wet wt.). We conclude that the brain appears to lack the ability to transport creatine when there is a mutation in the CrT gene. However, the muscle utilizes another mechanism for maintaining normal creatine levels. Identifying this alternative creatine-transport mechanism may be useful in treating the neurologic and cognitive impairments of patients with creatine-transporter deficiency.

Adult↗
PubMed2004

Arachnoid cyst of the optic nerve: a case report.

BACKGROUND: To report a case of an arachnoid cyst of the optic nerve with homonymous optic atrophy. HISTORY AND SIGNS: A 17-year-old female patient presented with severe visual loss, limited to light perception, of the left eye. She underwent complete ophthalmologic examination, color fundus photography and electrophysiological study. Magnetic resonance imaging (MRI) revealed the presence of a fusiform structure involving the left optic nerve from the orbital apex to the posterior surface of the globe. The clinical and radiographic features are consistent with an arachnoid cyst of the optic nerve. THERAPY AND OUTCOME: The patient refused to be treated. Two years later, the VA remained unchanged. CONCLUSIONS: The arachnoid cyst of the optic nerve is a rare entity. Its differential diagnosis from the primary optic nerve glioma is difficult and important to be made in order to be treated properly.

Adolescent↗
PubMed1997

The contribution of NMR, NIRS and their combination to the functional assessment of human muscle.

In the last decade the study of the human muscle mechanics and energetics in physiology and pathology underwent a radical change. Indeed, the use of biopsy is being progressively accompanied by non-invasive techniques which allow a more integrative assessment of muscle function in vivo. Magnetic resonance imaging (MRI) provides a better insight into muscle structure down to the fascicular level, proving to be an essential source of information, particularly for the study of biomechanics. Magnetic resonance spectroscopy (MRS), besides the study of muscle anaerobic (high energy phosphate compounds by 31P and 1H) and aerobic metabolism as well as of metabolic control, makes it possible to follow the time course of glycogen concentration (13C) as a function of exercise intensity and duration and of its recovery both in healthy trained and untrained subjects and in diabetic patients. Near-infrared spectroscopy (NIRS) allows to assess muscle oxidative metabolism, providing changes of total, deoxy- and oxy-hemoglobin in the resting and contracting muscle. The concomitant use of the above techniques is expected to provide a synergic functional picture of the human muscle that is complementary to the structural and ultrastructural microscopic approach.

Humans↗
PubMed2004

Early regression of left ventricular hypertrophy after aortic valve replacement by the Ross procedure detected by cine MRI.

AIM: The primary objective of our study was to assess the time course of left ventricular remodeling after the Ross procedure with the use of cine magnetic resonance imaging (MRI). METHODS: In a prospective study, 10 patients with isolated aortic valve disease were examined prior to aortic valve surgery, as well as at early follow-up (mean 4 weeks) and at late follow-up (mean 8 months) after pulmonary autograft aortic valve replacement (Ross procedure). The heart was imaged with a 1.5 T MR scanner along the short and long axes using a breath-hold, electrocardiogram (ECG)-triggered, cine gradient-echo sequence (FLASH). Myocardial mass and ventricular function were assessed. RESULTS: After aortic valve replacement, left ventricular myocardial mass (LVM) decreased by 13% (261 +/- 74 g to 230 +/- 65 g, p < 0.05) in the early postoperative period and by a further 16% in the late postoperative period to 192 +/- 31 g (p < 0.05). In addition, left ventricular end-diastolic and end-systolic volumes decreased from preoperative 187 +/- 89 mL (LV EDV) and 73 +/- 59 mL (LV ESV) to 119 +/- 55 mL and 56 +/- 42 mL, respectively, in the early postoperative period. In the late postoperative period, there was a further decrease to 98 +/- 30 (p < 0.05) and 33 +/- 19 mL, respectively. Ejection fraction did not change markedly after surgery (preoperatively 61 +/- 13% vs. 56 +/- 14% postoperatively). Patients with leading aortic stenosis were characterized by predominant regression of LVM and patients with leading aortic regurgitation by predominant regression of LV EDV (each p < 0.05). CONCLUSION: Cine MRI allows accurate assessment of left ventricular structure and geometry before and after aortic valve replacement with pulmonary autograft and is very sensitive in detecting relatively small changes of left ventricular myocardial mass and volumes early after hemodynamic relief as well as during serial assessment.

Adult↗
PubMed2001

Variability in the cardiac EIT image as a function of electrode position, lung volume and body position.

A study was conducted using the Sheffield electrical impedance tomography (EIT) portable system DAS-01 P to determine the change in the cardiac image with electrode position, lung volume and body position. Sixteen electrodes were positioned in three transverse planes around the thorax at the level of the second intercostal space, at the level of the xiphisternal joint, and midway between upper and lower locations. Data were collected at each electrode level with the breath held at end expiration and after inspiring 0.5, 1 and 1.5 l of air with the subject in both the supine and sitting position. These data were analysed using a Matlab developed program that calculates the average resistivity change in the cardiac region from automatically determined borders. Results show significant individual variability with electrode position and air volume. The middle electrode most consistently shows an increase in impedance in the region of the heart during systole. In some subjects the change in the ventricular-volume-like curve showed a greater than 50% change as a function of lung volume. The pattern of variability with electrode position was not consistent among subjects. In one subject MRI images were obtained to compare actual structures with those seen in the EIT image. The results suggest that using these electrode locations reliable and consistent data, which could be used in clinical applications, cannot be obtained.

Electric Impedance↗
PubMed2003

Addiction.

Alcohol and psycho-active substance misuse has far-reaching social, psychological and physical consequences. Advances in neuroimaging technology have allowed neurobiological theories of addiction to become better characterized. We describe the neurobiology of dependence, withdrawal, abstinence and craving states in alcohol, stimulant and opiate misuse. Structural neuroimaging techniques such as CT and MRI with new analytical approaches such as voxel-based morphometry have shown wide-spread changes in stimulant and opiate abuse and atrophy, particularly in the frontal lobes, in alcoholism. Functional neuroimaging techniques such as PET, SPECT and fMRI reveal altered regional cerebral activity by all drugs of abuse. The neurochemistry of addiction, particularly involving dopamine, serotonin, opiate and GABA, has been studied with PET and SPECT and similarities between all drugs of abuse have been found such as reduced dopaminergic markers. The evidence derived from these advances in neuroimaging is likely to herald the emergence of new biological treatments in this important field.

Brain↗

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