bluuebunny/crossref_metadata_2025 huggingface dataset:
Bioglass® coated poly(DL‐lactide) foams for tissue engineering scaffolds
Authors: Gough J. E. , Arumugam M. , Blaker J. , Boccaccini A. R.
Published: June 2003

The purpose of this study was to prepare poly(DL‐lactic acid) (PDLLA)/Bioglass® composites of foam‐like structure, to measure the degree of bioactivity of the composites by studying the formation of hydroxyapatite (HA) after immersion in simulated body fluid (SBF) and to test the initial attachment of human osteoblasts within the porous network. It was found that crystalline HA formed on the Bioglass® coated PDLLA foams after 7 days of immersion in SBF. HA formed also on the surfaces of non‐coated PDLLA foams, however the rate and amount of HA formation were much lower than in the composites. The rapid formation of HA on the Bioglass®/PDLLA foam surfaces confirmed the high bioactivity of these materials. Osteoblasts attached within the porous network throughout the depth of the foams. Cell density was found to be higher in the PDLLA/Bioglass® composites compared to the pure PDLLA foams. The composite foams developed here exhibit the required bioactivity to be used as scaffolds for bone tissue engineering.
Eliminating the Extinction‐Induced Reflection Enlargement in the XRD Characterisations of Textured Films
Authors: Tomov I.
Published: June 2003

This investigation throws additional light on the nature of secondary extinction (SE). A method is described for computing the correct integral breadth using the observed one, which is affected by SE. The method is applied for more precise measuring the integral breadths of reflections corresponding to the ideal directions of main texture components of electrodeposited silver films. Further, the effect of SE on the systematic error in integral breadth measurements is investigated in dependence on the reflectivity and pole density.
Essential tremor is not associated with α‐synuclein gene haplotypes
Authors: Pigullo Simona , Di Maria Emilio , Marchese Roberta , Bellone Emilia , Gulli Rossella , Scaglione Cesa , Battaglia Stella , Barone Paolo , Martinelli Paolo , Abbruzzese Giovanni , Ajmar Franco , Mandich Paola
Published: June 2003

A specific allele of the NACP‐Rep1 polymorphism within the α‐synuclein promoter was found to be associated both with Parkinson's disease and essential tremor. We repeated the association study on a large series of Italian patients with essential tremor using a panel of polymorphisms within the α‐synuclein gene. Our results did not confirm the association reported previously and failed to identify a α‐synuclein specific haplotype as susceptibility factor for essential tremor. © 2003 Movement Disorder Society
Clinical features and neuroimaging of PARK7‐linked parkinsonism
Authors: Dekker Marieke , Bonifati Vincenzo , van Swieten John , Leenders Nico , Galjaard Robert‐Jan , Snijders Pieter , Horstink Marten , Heutink Peter , Oostra Ben , van Duijn Cornelia
Published: June 2003

We recently reported linkage to chromosome 1p36 (the PARK7‐locus) in a family with early‐onset parkinsonism. Linkage to this locus has since been confirmed in an independent data set. We describe clinical and neuroimaging features of the 4 patients in the original PARK7‐linked kindred. Age at onset of parkinsonism varied from 27 to 40 years. Clinical progression was slow, and response to dopaminergic therapy good. The clinical spectrum ranged from mild hypokinesia and rigidity, to severe parkinsonism with levodopa‐induced dyskinesias and motor fluctuation. Three of four patients with PARK7‐linked parkinsonism exhibited psychiatric disturbances. Structural neuroimaging was unremarkable, but functional imaging of the brain, carried out in 3 patients, showed significant evidence for a presynaptic dopamine deficit, and assessment of cerebral glucose metabolism, as carried out in 1 patient, showed possible cerebellar involvement. © 2003 Movement Disorder Society
Chorea as a presenting feature of variant Creutzfeldt‐Jakob disease
Authors: McKee David , Talbot Paul
Published: June 2003

We report on a patient with pathologically proven variant Creutzfeld‐Jakob disease in whom chorea was a presenting feature of the disease, and was unaccompanied by the typical prodrome of psychiatric disturbance or sensory symptoms. © 2003 Movement Disorder Society
Lack of effect of polymorphisms in dopamine metabolism related genes on imaging of TRODAT‐1 in striatum of asymptomatic volunteers and patients with Parkinson's disease
Authors: Lynch David R. , Mozley P. David , Sokol Set , Maas Nicole M.C. , Balcer Laura J. , Siderowf Andrew D.
Published: June 2003

SPECT scanning using 99Tc‐TRODAT‐1, a ligand that binds to dopamine transporters, may be useful for detection of early Parkinson's disease (PD), diagnosis of presymptomatic individuals, and monitoring disease progression. Understanding whether genetic factors contribute to inter‐individual variability is crucial for interpreting imaging results in the context of disease pathophysiology. We tested whether polymorphisms in the genes for catechol‐O‐methyltransferase (COMT), monoamine‐oxidase B (MAO‐B), and the dopamine transporter (DAT) influence dopamine uptake parameters in the striatum in vivo in asymptomatic volunteers and patients with PD as measured with 99Tc‐TRODAT‐1. 99Tc‐TRODAT‐1 binding declined with age in both asymptomatic volunteers and PD patients, and depended on disease duration in PD patients. We found no significant association between COMT, MAO‐B, and DAT polymorphisms and results of 99Tc‐TRODAT‐1 testing in asymptomatic volunteers or patients with PD. In PD patients, the age of disease onset and speed of progression did not differ based on these polymorphisms. These results demonstrate that these specific genetic variations do not alter the fidelity of 99Tc‐TRODAT‐1 as a measure of dopaminergic function in asymptomatic volunteer individuals or patients with PD. © 2003 Movement Disorder Society
Marked variation in clinical presentation and age of onset in a family with a heterozygous parkin mutation
Authors: Tan Louis C. , Tanner Caroline M. , Chen Rong , Chan Piu , Farrer Matthew , Hardy John , Langston J. William
Published: June 2003

Parkin gene mutations have been detected in families with early‐onset autosomal recessive parkinsonism. We report a novel heterozygous 40 base pair deletion in exon 3 of the parkin gene that increases the susceptibility of carriers to develop parkinsonism/dystonia and manifests remarkable variability in regard to age of onset and phenotype in a single family. After identifying the new mutation in the proband of this kindred, family members were contacted and evaluated by a movement disorders specialist using standardized protocols and prospectively set diagnostic criteria. Importantly, examining physicians and family members were blinded to the genetic testing. Five affected members in two generations carried the parkin mutation. The proband and one of his brothers had disease onset at 24 years of age while another brother had disease at age 44. One exhibited multi‐focal dystonia and parkinsonism of 17 years duration, another suffered a unilateral slowly progressive parkinsonism over 13 years while the third suffered dystonia–parkinsonism of recent onset. A sibling pair in the preceding generation had mild previously undiagnosed parkinsonism. Clinicians should be aware that patients carrying a parkin gene mutation may present with dystonia–parkinsonism or very subtle parkinsonism with a markedly varied age of onset. © 2003 Movement Disorder Society
Tongue tremor in a patient with coma after electrical injury
Authors: Lin Katia , Lin Jaime , Piovesan Elcio Juliato , Germiniani Francisco M.B. , Teive Hélio A.G. , Werneck Lineu Cesar
Published: June 2003

We report on the case of a patient with transient tongue tremor and coma after electrical injury, probably due to a reversible brainstem dysfunction. We then reviewed the differential diagnosis of abnormal involuntary movements of the tongue as well as movement disorders related to electrocution. © 2003 Movement Disorder Society
Influence of target size on vertical gaze palsy in a pathologically proven case of progressive supranuclear palsy
Authors: Seemungal Barry M. , Faldon Mary , Revesz Tamas , Lees Andrew J. , Zee David S. , Bronstein Adolfo M.
Published: June 2003

We document a new oculomotor phenomenon in a patient with pathologically proven progressive supranuclear gaze palsy (PSP), namely that vertical gaze excursion improves with larger pursuit targets. We used computerised video‐oculography during vertical smooth pursuit eye movements (SPEM) of circular targets of diameter 0.16 degrees and 16 degrees, sinusoidally oscillating at 0.08 Hz (peak‐to‐peak amplitude 49 degrees). Increasing target size improved vertical gaze excursion from 10 degrees to 25 degrees. There was no concomitant increase in slow phase eye velocity. The findings could be explained by a potentiation of the position control mechanism of pursuit by target size due to increased activation of brainstem pursuit‐optokinetic pathways and to higher order attentional mechanisms. This observation may be useful in the clinical assessment of PSP patients with severe neck rigidity in whom the doll's head–eye manoeuvre cannot be performed by comparing the degree of vertical gaze palsy during smooth pursuit testing between at least two differently sized targets and observing whether there is a larger excursion in response to a large target such as a newspaper. © 2003 Movement Disorder Society
Episodic focal lingual dystonic spasms
Authors: Edwards Mark , Schott Geoffrey , Bhatia Kailash
Published: June 2003

We present the clinical history of a woman with idiopathic episodic focal lingual dystonic spasms. Although dystonic spasms of the tongue have been reported as a primary persistent phenomenon and as a feature of secondary dystonias, primary episodic lingual dystonias are rare, tend to be unilateral, and in contrast to most other paroxysmal movement disorders, do not appear responsive to anti‐epileptic drugs. © 2003 Movement Disorder Society
An artist's view of drug‐induced hallucinosis
Authors: Ebersbach Georg
Published: June 2003

The occurrence of hallucinations in patients with Parkinson's disease is often related to antiparkinsonian therapy, but other factors such as cognitive decline and sleep‐cycle disturbances are thought to contribute. We describe an artist who depicted her visual hallucinations experienced in the course of Parkinson's disease. © 2003 Movement Disorder Society
Health status measurement in Parkinson's disease: Validity of the PDQ‐39 and Nottingham Health Profile
Authors: Hagell Peter , Whalley Diane , McKenna Stephen P. , Lindvall Olle
Published: June 2003

We assessed the feasibility and psychometric properties of two commonly used health status questionnaires in Parkinson's disease (PD): the generic Nottingham Health Profile (NHP) and the disease‐specific 39‐item Parkinson's disease Questionnaire (PDQ‐39), from a cross‐sectional postal survey of PD patients (N = 81), using traditional and Rasch measurement methodologies. Overall response rate was 88%. Both questionnaires were found feasible, although the NHP performed less well. The PDQ‐39 had fewer floor effects and was better able to separate respondents into distinct groups than the NHP, whereas the latter exhibited less ambiguous dimensionality and better targeting of respondents with non‐extreme scores. Reliability and validity indices were similar, and potential differential item functioning by age and gender groups was found for both questionnaires. PDQ‐39 response alternatives indicated ambiguity. With few exceptions, questionnaire scales were unable to meet recommended standards fully. While preliminary, this study illustrates the need for thorough evaluation of outcome measures and has implications beyond the questionnaires used here. Although promising, both questionnaires warrant further developmental work and stronger support of measurement validity before they could be considered fully suitable for valid use in PD, in particular in earlier stages of the disease. © 2003 Movement Disorder Society
Visual hallucinations as REM sleep behavior disorders in patients with Parkinson's disease
Authors: Nomura Takashi , Inoue Yuichi , Mitani Hidetaka , Kawahara Ryuzo , Miyake Masahiro , Nakashima Kenji
Published: June 2003

To clarify whether visual hallucinations in patients with Parkinson's disease (PD) are related to rapid eye movement (REM) sleep, nocturnal polysomnographic variables were compared between a group with hallucinations (hallucinators, n = 14) and a group without hallucinations (nonhallucinators, n = 8). A multiple sleep latency test (MSLT) was performed on 3 hallucinators, and the content of dreams during daytime REM sleep was investigated. The efficacy of clonazepam, a standard treatment choice for REM sleep behavior disorders, was investigated in 8 hallucinators. Nocturnal polysomnograms of the hallucinators showed a higher amount of stage 1–REM sleep with tonic electromyogram (stage 1–REM) than the nonhallucinators, and the reported occurrences of nocturnal hallucinations corresponded with the periods of stage REM or stage 1–REM in most hallucinators. The frequency of sleep onset REM periods (SOREMP) on the MSLT were pathologically high in the hallucinators, and the content of the dreams during the MSLT period was quite similar to their hallucinations. During clonazepam treatment, the frequency of hallucinatory symptoms decreased in 5 of 8 hallucinators. These results indicate that visual hallucinations in PD are likely to be related to a REM sleep disorder manifested as the appearance of both stage 1–REM during the night and SOREMP in the daytime. © 2003 Movement Disorder Society
Familial influence on parkinsonism in a rural area of Turkey (Kızılcaboluk–Denizli): A community‐based case‐control study
Authors: Duzcan Fusun , Zencir Mehmet , Ozdemir Fatma , Cetin G. Ozan , Bagci Huseyin , Heutink Peter , Bonifati Vincenzo , Sahiner Turker
Published: June 2003

This population‐based study on parkinsonism in a genetically isolated community from a rural area of Turkey aimed to provide a selective evaluation of environmental and heritable risk factors. An increased prevalence of parkinsonism (4.1%) was detected in the village of Kızılcaboluk for people 65 years of age and older. This study included 36 patients with parkinsonism living in Kızılcaboluk and three times that number of age‐ and sex‐matched people serving as controls. A questionnaire including demographic data, family history, education, occupation, data on exposures to pesticides, smoking, alcohol intake, and head trauma was administered. We found a significant association of parkinsonism cases with a positive family history in first‐degree relatives (odds ratio [OR], 7.48; 95% confidence interval [CI], 2.52–22.17; P < 0.0001) and with pesticide exposure (OR, 2.96; 95% CI, 1.31–6.69; P = 0.015) compared to the control subjects. The value of genetically isolated populations for the identification of genetic risk factors for common and complex disorders has gained much attention recently because the genetic make‐up of these populations is likely to be less complex than that of the general population and our findings should prompt investigations to the nature of a familial aggregation of parkinsonism in this population. © 2003 Movement Disorder Society
Normal intracortical excitability in developmental stuttering
Authors: Sommer Martin , Wischer Stephan , Tergau Frithjof , Paulus Walter
Published: June 2003

Persistent developmental stuttering (PDS) shares clinical features with task‐specific dystonias. In these dystonias, intracortical inhibition is abnormally weak. We therefore sought to determine intracortical inhibition and intracortical facilitation in PDS. In 18 subjects with PDS since childhood (mean age, 39.4 [SD 13.0] years) and 18 speech‐fluent controls (43.6 [14.3] years), we investigated resting and active motor thresholds as well as intracortical inhibition and facilitation of the optimal representation of the abductor digiti minimi of the dominant hand using transcranial magnetic stimulation. In PDS, the resting and active motor thresholds were increased, whereas intracortical inhibition and facilitation were normal. Normal intracortical excitability makes a pathophysiological analogy between focal dystonia and PDS less likely. The enhanced motor threshold suggests reduced motor cortical neuronal membrane excitability in PDS. © 2003 Movement Disorder Society
Parkinson's disease is associated with hippocampal atrophy
Authors: Camicioli Richard , Moore M. Milar , Kinney Anthony , Corbridge Elizabeth , Glassberg Kathryn , Kaye Jeffrey A.
Published: June 2003

Patients with Parkinson's disease (PD) may have hippocampal atrophy compared with controls. We compared hippocampal, and extra‐hippocampal volumes between PD, PDD (patients with PD who have mild cognitive impairment or dementia), Alzheimer's disease (AD) and controls using volumetric magnetic resonance imaging (MRI). Participants (10 patients with PD, 10 with PDD, 11 with AD, and 12 control subjects) had an informant interview, neurological examination, and psychometric testing. Established, reliable methods were used to measure the hippocampus, parahippocampal gyrus, temporal, frontal, and parieto‐occipital lobes. Correction for intracranial volume was carried out before comparison. There was no age difference between groups (mean age, 74 years). On the Clinical Dementia Rating scale (CDR) cognitive impairment was mild (CDR = 0.5) in the majority of PDD and AD patients. Hippocampal (P < 0.0004) volumes were smaller in the patient groups. Effect sizes compared with the control group were: PD, 0.66; PDD, 1.22; and AD, 1.81. The other volumes did not differ significantly. Among PD and PDD patients, recognition memory (r = 0.54, P = 0.015) and Mini‐Mental State Examination scores (r = 0.56, P = 0.01) correlated with left, but not right hippocampal volume. In conclusion, hippocampal volume showed a pattern (Control > PD > PDD > AD) suggesting progressive hippocampal volume loss in PD. Volumetric MRI imaging might provide an early marker for dementia in PD. © 2003 Movement Disorder Society
Prevalence of Parkinson's disease and related disorders in the elderly population of greater Beijing, China
Authors: Zhang Zhen‐Xin , Anderson Dallas W. , Huang Jue‐Bin , Li Hui , Hong Xia , Wei Jing , Yang En‐Li , Maraganore Demetrius M.
Published: June 2003

A lower prevalence of Parkinson's disease (PD) has been reported for Chinese populations, but it is unclear whether this observation reflects a lower disease risk or is an artifact of case finding. We ascertained the prevalence of PD in elderly residents of an area that was a composite of 27 urban and rural communities of Greater Beijing, China. A team of university neurologists went door‐to‐door throughout the study area, examining 5,743 residents (at age 55 years or older) and made preliminary determinations of which residents had PD or other types of parkinsonism. Final determinations were made after follow‐up and reevaluation of those persons who were either deemed to have parkinsonism or were suspected of having the condition (n = 144; median follow‐up = 40 months). Based on stringent diagnostic criteria, 110 persons were identified to have parkinsonism, of whom 64 (58%) had PD. The prevalence of PD increased with advancing age and was about 1% overall and for each gender. In rural communities, 22 persons had PD, but 20 persons (91%) were first diagnosed for this condition by the study neurologists. The prevalence figures obtained in this study are similar to some of the highest prevalence figures reported in the West. © 2003 Movement Disorder Society
Locations of movement‐related cells in the human subthalamic nucleus in Parkinson's disease
Authors: Theodosopoulos Philip V. , Marks William J. , Christine Chadwick , Starr Philip A.
Published: June 2003

The subthalamic nucleus (STN) is an emerging target for deep brain stimulator (DBS) implantation for the treatment of advanced Parkinson's disease (PD). Understanding the somatotopic organization of the STN is important for surgical navigation within the nucleus. We analyzed intraoperative data obtained during 54 procedures for the implantation of STN stimulators to assess the locations of movement‐related cells. Cells were considered movement‐related if they exhibited modulation of the cell discharge during passive movement of the contralateral upper or lower extremity. Microelectrode track reconstructions were plotted on a human brain atlas, using the location of the DBS electrode from postoperative magnetic resonance images as a registration mark in reconstructing microelectrode track locations. Movement‐related cells were predominantly located in the dorsal part of the nucleus. The majority of the cells were related to proximal joint manipulation. Arm‐related cells were located laterally and at the rostral and caudal poles, whereas leg‐related cells were located medially and centrally. The finding of three or more leg‐related cells on a given microelectrode track was predictive of a medial localization within the motor area. Our findings are consistent with the small number of published studies on STN somatopy in the human and the nonhuman primate. © 2003 Movement Disorder Society
Models of Parkinson's disease
Authors: Orth Michael , Tabrizi Sarah J.
Published: June 2003

Parkinson's disease (PD) is a heterogenous disease likely to be caused by more than one specific aetiological factor. In rare familial cases of PD with similar clinical features to the idiopathic form of the disease, the underlying genetic cause has been identified. These PD‐associated genes have been manipulated to create animal and cell culture models of the disease that have helped to further our understanding of the pathogenesis of PD, particularly concerning causes of the selective loss of dopaminergic neurons at the molecular level. In addition, these models will aid the future development of rational therapeutic strategies. This study briefly reviews toxin‐induced models and the genetics of PD. It focuses on recently developed animal models of PD, as well as in vitro approaches to model the disease. © 2003 Movement Disorder Society
Coping strategies for visual hallucinations in Parkinson's disease
Authors: Diederich Nico J. , Pieri Vannina , Goetz Christopher G.
Published: June 2003

We assessed the use of coping strategies in Parkinson's disease patients with visual hallucinations, using a semi‐structured questionnaire. We found that 36 of our 46 Parkinson's disease subjects with hallucinations (78%) used coping strategies: cognitive techniques in 69%; interactive techniques in 62%; and visual techniques in 33%. © 2003 Movement Disorder Society
The Unified Parkinson's Disease Rating Scale (UPDRS): Status and recommendations
Authors:   Movement Disorder Society Task Force on Rating Scales for Parkinson's Disease
Published: June 2003

The Movement Disorder Society Task Force for Rating Scales for Parkinson's Disease prepared a critique of the Unified Parkinson's Disease Rating Scale (UPDRS). Strengths of the UPDRS include its wide utilization, its application across the clinical spectrum of PD, its nearly comprehensive coverage of motor symptoms, and its clinimetric properties, including reliability and validity. Weaknesses include several ambiguities in the written text, inadequate instructions for raters, some metric flaws, and the absence of screening questions on several important non‐motor aspects of PD. The Task Force recommends that the MDS sponsor the development of a new version of the UPDRS and encourage efforts to establish its clinimetric properties, especially addressing the need to define a Minimal Clinically Relevant Difference and a Minimal Clinically Relevant Incremental Difference, as well as testing its correlation with the current UPDRS. If developed, the new scale should be culturally unbiased and be tested in different racial, gender, and age‐groups. Future goals should include the definition of UPDRS scores with confidence intervals that correlate with clinically pertinent designations, “minimal,” “mild,” “moderate,” and “severe” PD. Whereas the presence of non‐motor components of PD can be identified with screening questions, a new version of the UPDRS should include an official appendix that includes other, more detailed, and optionally used scales to determine severity of these impairments. © 2003 Movement Disorder Society
Electromagnetic actuator for generating variably oriented shear waves in MR elastography
Authors: Braun Juergen , Braun Karl , Sack Ingolf
Published: June 2003

Magnetic resonance elastography (MRE) is a recently developed technique for determining the mechanical properties of biological tissue. In dynamic MRE, electromagnetic units (actuators) are widely used to generate shear waves in tissue. These actuators exploit the interaction between the static magnetic field B0 and an annular coil supplied with alternating currents. Therefore, coil movements are restricted to selected orientations to B0. Conventional actuators transfer this movement collinearly to B0 into the tissue. In this study, an electromagnetic actuator was introduced that overcomes this limitation. It is demonstrated that different directions of mechanical excitation can be generated and monitored by MRE. Different spatial components of the propagation of the shear waves were determined using agarose phantoms. The technique allows maximum contrast for MRE images of objects with anisotropic strain components such as muscle tissue. Magn Reson Med 50:220–222, 2003. © 2003 Wiley‐Liss, Inc.
Diffusely elevated cerebral choline and creatine in relapsing‐remitting multiple sclerosis
Authors: Inglese Matilde , Li Belinda S.Y. , Rusinek Henry , Babb James S. , Grossman Robert I. , Gonen Oded
Published: June 2003

It is well known that multiple sclerosis (MS) pathogenesis continues even during periods of clinical silence. To quantify the metabolic characteristics of this activity we compared the absolute levels of N‐acetylaspartate (NAA), creatine (Cr), and choline (Cho) in the normal‐appearing white matter (NAWM) between relapsing‐remitting (RR) MS patients and controls. Metabolite concentrations were obtained with 3D proton MR spectroscopy at 1.5 T in a 480 cm3 volume‐of‐interest (VOI), centered on the corpus callosum of 11 MS patients and 9 matched controls. Gray/white‐matter/cerebral‐spinal‐fluid (CSF) volumes were obtained from MRI segmentation. Patients' average VOI tissue volume (VT), 410.8 ± 24.0 cm3, and metabolite levels, NAA = 6.33 ± 0.70, Cr = 4.67 ± 0.52, Cho = 1.40 ± 0.17 mM, were different from the controls by –8%, –9%, +22% and +32%. The Cho level was the only single metric differentiating patients from controls at 100% specificity and >90% sensitivity. Diffusely elevated Cho and Cr probably reflect widespread microscopic inflammation, gliosis, or de‐ and remyelination in the NAWM. Both metabolites are potential prognostic indicators of current disease activity, preceding NAA decline and atrophy. Magn Reson Med 50:190–195, 2003. © 2003 Wiley‐Liss, Inc.
Combined diffusion and strain MRI reveals structure and function of human myocardial laminar sheets in vivo
Authors: Dou Jiangang , Tseng Wen‐Yih I. , Reese Timothy G. , Wedeen Van J.
Published: June 2003

The mechanism of ventricular thickening in normal humans was investigated using in vivo MRI. The hypothesis that myocardial laminar sheets contribute to ventricular thickening predominantly via sheet shear and sheet extension, as previously found invasively in canine studies at particular ventricular sites, was tested. In normal human subjects, registered images of myocardial sheet architecture and strain at the mid‐left ventricle (mid‐LV) at mid‐systole were acquired with diffusion and strain MRI. Sheet function was analyzed by computing myocardial strain in the local fiber‐sheet coordinates. In general, myocardial sheets contribute to ventricular thickening through all three cross‐fiber strain components: sheet shear, sheet extension, and sheet‐normal thickening (previously undocumented). Each of these components demonstrated substantial spatial heterogeneity, with sheet shear and sheet extension usually predominant in the anterior free wall, and sheet‐normal thickening predominant near the right ventricular (RV) insertions. However, considerable intersubject variability was also found. In all cases, the contributions to thickening of fiber strains were small. Sheet function in normal humans was found to be heterogeneous and variable, contrasting with the uniform and symmetric ventricular patterns of fiber shortening and wall thickening. The study demonstrates that noninvasive NMR imaging is a promising tool for investigations of myocardial sheet architecture and function, and is particularly suited to the evident complexity of this field of study. Magn Reson Med 50:107–113, 2003. © 2003 Wiley‐Liss, Inc.
Novel prospective respiratory motion correction approach for free‐breathing coronary MR angiography using a patient‐adapted affine motion model
Authors: Manke Dirk , Nehrke Kay , Börnert Peter
Published: June 2003

A novel technique is presented which enables the calibration of a 3D affine respiratory motion model to the individual motion pattern of the patient. The concept of multiple navigators and precursory navigators is introduced to address nonlinear properties and hysteresis effects of the model parameters with respect to the conventional diaphragmatic navigator. The optimal combination and weighting of the navigators is determined on the basis of a principal component analysis (PCA). Thus, based on a given navigator measurement the current motion state of the object can be predicted by means of the calibrated motion model. The 3D motion model is applied in high‐resolution coronary MR angiography examinations (CMRA) to prospectively correct for respiration‐induced motion. The basic feasibility of the proposed calibration procedure was shown in 16 volunteers. Furthermore, the application of the calibrated motion model for CMRA examinations of the right coronary artery (RCA) was tested in 10 volunteers. The superiority of a calibrated 3D translation model over the conventional 1D translation model with a fixed correction factor and the potential of affine prospective motion correction for CMRA are demonstrated. Magn Reson Med 50:122–131, 2003. © 2003 Wiley‐Liss, Inc.
Control characteristics of an automatic matching control system for in vivo EPR spectroscopy
Authors: Hirata Hiroshi , Yamaguchi Yasunori , Takahashi Tatsuhisa , Luo Zhi‐Wei
Published: June 2003

A method for estimating the characteristics of an automatic matching control (AMC) system for in vivo electron paramagnetic resonance (EPR) spectroscopy is described. AMC is also known as automatic coupling control (ACC) and is used to compensate for perturbation due to movement of the subject animal. The open‐loop function of the AMC system is derived and the characteristics (gain, phase margin, steady‐state error, system bandwidth, and disturbance rejection) of the system are examined. The proposed method is supported by experimental findings. The frequency response of perturbation due to the movement of an anesthetized rat was measured with a 1.1‐GHz continuous‐wave EPR spectrometer. Disturbance rejection with the AMC system was also considered for respiratory motion and the heartbeat of the anesthetized rat, and these perturbations were reduced by about 40 dB in the power spectrum of the output of the diode detector in the spectrometer. Magn Reson Med 50:223–227, 2003. © 2003 Wiley‐Liss, Inc.
Fat‐suppressed steady‐state free precession imaging using phase detection
Authors: Hargreaves Brian A. , Vasanawala Shreyas S. , Nayak Krishna S. , Hu Bob S. , Nishimura Dwight G.
Published: June 2003

Fully refocused steady‐state free precession (SSFP) is a rapid, efficient imaging sequence that can provide diagnostically useful image contrast. In SSFP, the signal is refocused midway between excitation pulses, much like in a spin‐echo experiment. However, in SSFP, the phase of the refocused spins alternates for each resonant frequency interval equal to the reciprocal of the sequence repetition time (TR). Appropriate selection of the TR results in a 180° phase difference between lipid and water signals. This phase difference can be used for fat–water separation in SSFP without any increase in scan time. The technique is shown to produce excellent non‐contrast‐enhanced, flow‐independent angiograms of the peripheral vasculature. Magn Reson Med 50:210–213, 2003. © 2003 Wiley‐Liss, Inc.
Spatial normalization of diffusion tensor fields
Authors: Xu Dongrong , Mori Susumu , Shen Dinggang , van Zijl Peter C.M. , Davatzikos Christos
Published: June 2003

A method for the spatial normalization and reorientation of diffusion tensor (DT) fields is presented. Spatial normalization of tensor fields requires an appropriate reorientation of the tensor on each voxel, in addition to its relocation into the standardized space. This appropriate tensor reorientation is determined from the spatial normalization transformation and from an estimate of the underlying fiber direction. The latter is obtained by treating the principal eigenvectors of the tensor field around each voxel as random samples drawn from the probability distribution that represents the direction of the underlying fiber. This approach was applied to DT images from nine normal volunteers, and the results show a significant improvement in signal‐to‐noise ratio (SNR) after spatial normalization and averaging of tensor fields across individuals. The statistics of the spatially normalized tensor field, which represents the tensor characteristics of normal individuals, may be useful for quantitatively characterizing individual variations of white matter structures revealed by DT imaging (DTI) and deviations caused by pathology. Simulated experiments using this methodology are also described. Magn Reson Med 50:175–182, 2003. © 2003 Wiley‐Liss, Inc.
Robust myelin water quantification: Averaging vs. spatial filtering
Authors: Jones Craig K. , Whittall Kenneth P. , MacKay Alex L.
Published: June 2003

The myelin water fraction is calculated, voxel‐by‐voxel, by fitting decay curves from a multi‐echo data acquisition. Curve‐fitting algorithms require a high signal‐to‐noise ratio to separate T2 components in the T2 distribution. This work compared the effect of averaging, during acquisition, to data postprocessed with a noise reduction filter. Forty regions, from five volunteers, were analyzed. A consistent decrease in the myelin water fraction variability with no bias in the mean was found for all 40 regions. Images of the myelin water fraction of white matter were more contiguous and had fewer “holes” than images of myelin water fractions from unfiltered echoes. Spatial filtering was effective for decreasing the variability in myelin water fraction calculated from 4‐average multi‐echo data. Magn Reson Med 50:206–209, 2003. © 2003 Wiley‐Liss, Inc.
Simple analytic variable density spiral design
Authors: Kim Dong‐hyun , Adalsteinsson Elfar , Spielman Daniel M.
Published: June 2003

Variable density spirals have been proposed in a variety of applications, including MR fluoroscopy, cardiac imaging, and MR spectroscopic imaging. In this work, a simple analytic solution for designing a flexible set of variable density spiral trajectory waveforms is presented. The method enables real‐time waveform prescription on scanners with limited computational power. Both slew rate‐limited and amplitude‐limited regimes are incorporated in the design process. Magn Reson Med 50:214–219, 2003. © 2003 Wiley‐Liss, Inc.
MRI detection of weak magnetic fields due to an extended current dipole in a conducting sphere: A model for direct detection of neuronal currents in the brain
Authors: Konn Daniel , Gowland Penny , Bowtell Richard
Published: June 2003

To investigate the feasibility of direct MR detection of neuronal activity in the brain, neuronal current flow was modeled as an extended current dipole located in a conducting sphere. The spatially varying magnetic field induced within the sphere by such a dipole was calculated, including its form close to and within the current source. The predicted field variation was experimentally verified by measurements of the variation in phase of the MR signal in a sphere containing a model dipole. The effects of the calculated magnetic field distributions on the phase and magnitude of the signal in MR images were explored. The minimum detectable dipole strength under normal experimental conditions was calculated to be about 4.5 nAm, which is similar in magnitude to dipole strengths from evoked neuronal activity, and is an order of magnitude smaller than dipole strengths expected from spontaneous activity. This minimum detectable dipole strength increases with increasing spatial extent of the primary current distribution. In the experimental work, the effects of a field of [1.1 ± 0.5] × 10–10 T strength were detected, corresponding to the maximum net field caused by a dipole of 6.3 nAm strength with a spatial extent of 3 × 3 × 2 mm3. Magn Reson Med 50:40–49, 2003. © 2003 Wiley‐Liss, Inc.
Parallel spectroscopic imaging with spin‐echo trains
Authors: Dydak Ulrike , Pruessmann Klaas P. , Weiger Markus , Tsao Jeffrey , Meier Dieter , Boesiger Peter
Published: June 2003

A reduction in scan time in spectroscopic imaging (SI) can be achieved by both fast and reduced k‐space sampling. This work presents an ultrafast SI technique that combines the two approaches. The synergy of multiple spin‐echo (MSE) acquisition and sensitivity encoding (SENSE) enables high‐resolution SI to be performed within a clinically acceptable scan time. MSE‐SENSE‐SI with echo train lengths ranging from one to four echoes is evaluated with respect to SNR and spatial response function by means of in vitro experiments. It is shown that acquiring two spin‐echoes (SEs) per acquisition yields a good practical trade‐off among scan time, SNR, and spatial response. The clinical feasibility of the technique is demonstrated in a patient with an astrocytoma, and SI data are obtained with an image matrix of 24 × 24 in just over 2 min. Magn Reson Med 50:196–200, 2003. © 2003 Wiley‐Liss, Inc.
Textural analysis of contrast‐enhanced MR images of the breast
Authors: Gibbs Peter , Turnbull Lindsay W.
Published: June 2003

Texture analysis was applied to high‐resolution, contrast‐enhanced (CE) images of the breast to provide a method of lesion discrimination. Significant differences were seen between benign and malignant lesions for a number of textural features, including entropy and sum entropy. Using logistic regression analysis (LRA), a diagnostic accuracy of Az = 0.80 ± 0.07 was obtained with a model requiring only three parameters. By initially dividing the patient data into training and test datasets, reasonable model robustness was also established. On combining features obtained using textural analysis with lesion size, time to maximum enhancement, and patient age, a diagnostic accuracy of Az = 0.92 ± 0.05 was demonstrated. Magn Reson Med 50:92–98, 2003. © 2003 Wiley‐Liss, Inc.
Developmental and regional changes in the neurochemical profile of the rat brain determined by in vivo 1H NMR spectroscopy
Authors: Tkáč Ivan , Rao Raghavendra , Georgieff Michael K. , Gruetter Rolf
Published: June 2003

Sixteen metabolites were quantified from 11–24 μl volumes in three different brain regions (hippocampus, striatum, and cerebral cortex) during postnatal development. Rat pups from the same litter were repeatedly measured on postnatal days 7, 10, 14, 21, and 28 using a completely noninvasive and longitudinal study design. Metabolite quantification was based on ultra‐short echo‐time 1H NMR spectroscopy at 9.4 T and LCModel processing. Most of the brain metabolites were quantified with Cramer‐Rao lower bounds (CRLB) less than 20%, which corresponded to an estimated concentration error <0.2 μmol/g. Taurine and total creatine were quantified with CRLB ≤ 5% from all 114 processed spectra. The resulting high reliability and reproducibility revealed significant regional and age‐related changes in metabolite concentrations. The most sensitive markers for developmental and regional variations between hippocampus, striatum, and cerebral cortex were N‐acetylaspartate, myo‐inositol, taurine, glutamate, and choline compounds. Absolute values of metabolite concentrations were in very good agreement with previously published in vitro results based on chromatographic measurements of brain extracts. The current data may serve as a reference for studies focused on developmental defects and pathologies using neonatal rat models. Magn Reson Med 50:24–32, 2003. © 2003 Wiley‐Liss, Inc.
In vivo trans‐synaptic tract tracing from the murine striatum and amygdala utilizing manganese enhanced MRI (MEMRI)
Authors: Pautler Robia G. , Mongeau Raymond , Jacobs Russell E.
Published: June 2003

Small focal injections of manganese ion (Mn2+) deep within the mouse central nervous system combined with in vivo high‐resolution MRI delineate neuronal tracts originating from the site of injection. Previous work has shown that Mn2+can be taken up through voltage‐gated Ca2+channels, transported along axons, and across synapses. Moreover, Mn2+is a paramagnetic MRI contrast agent, causing positive contrast enhancement in tissues where it has accumulated. These combined properties allow for its use as an effective MRI detectable neuronal tract tracer. Injections of low concentrations of MnCl2into either the striatum or amygdala produced significant contrast enhancement along the known neuronal circuitry. The observed enhancement pattern is different at each injection site and enhancement of the homotopic areas was observed in both cases. Ten days postinjection, the Mn2+had washed out, as evidenced by the absence of positive contrast enhancement within the brain. This methodology allows imaging of neuronal tracts long after the injection of the ion because Mn2+concentrates in active neurons and resides for extended periods of time. With appropriate controls, differentiation of subsets of neuronal pathways associated with behavioral and pharmacological paradigms should be feasible. Magn Reson Med 50:33–39, 2003. © 2003 Wiley‐Liss, Inc.
Measurement of reduced glutathione (GSH) in human brain using LCModel analysis of difference‐edited spectra
Authors: Terpstra Melissa , Henry Pierre‐Gilles , Gruetter Rolf
Published: June 2003

The concentration of reduced glutathione (GSH), an antioxidant, may be altered in various brain diseases. MEGA‐PRESS was used to edit for the 1H NMR signal from GSH in the occipital lobe of 12 normal humans. In all studies, GSH was clearly detected with a spectral pattern consistent with spectra acquired from a phantom containing GSH. Retention of singlet resonances in the subspectra, a key advantage of this difference‐editing technique, provided an unambiguous reference for the offset and phase of the edited signal. Linear combination model (LCModel) analysis provided an unbiased means for quantifying signal contribution from edited metabolites. GSH concentration was estimated from the in vivo spectra as 1.3 ± 0.2 μmol/g (mean ± SD, n = 12). Magn Reson Med 50:19–23, 2003. © 2003 Wiley‐Liss, Inc.
High‐resolution MRI with cardiac and respiratory gating allows for accurate in vivo atherosclerotic plaque visualization in the murine aortic arch
Authors: Wiesmann Frank , Szimtenings Michael , Frydrychowicz Alex , Illinger Ralf , Hunecke Andreas , Rommel Eberhard , Neubauer Stefan , Haase Axel
Published: June 2003

Genetically engineered mouse models provide enormous potential for investigation of the underlying mechanisms of atherosclerotic disease, but noninvasive imaging methods for analysis of atherosclerosis in mice are currently limited. This study aimed to demonstrate the feasibility of MRI to noninvasively visualize atherosclerotic plaques in the thoracic aorta in mice deficient in apolipoprotein‐E, who develop atherosclerotic lesions similar to those observed in humans. To freeze motion, MR data acquisition was both ECG‐ and respiratory‐gated. T1‐weighted MR images were acquired with TR/TE ∼1000/10 ms. Spatial image resolution was 49 × 98 × 300 μm3. MRI revealed a detailed view of the lumen and the vessel wall of the entire thoracic aorta. Comparison of MRI with corresponding cross‐sectional histopathology showed excellent agreement of aortic vessel wall area (r = 0.97). Hence, noninvasive MRI should allow new insights into the mechanisms involved in progression and regression of atherosclerotic disease. Magn Reson Med 50:69–74, 2003. © 2003 Wiley‐Liss, Inc.
Centering the projection reconstruction trajectory: Reducing gradient delay errors
Authors: Peters Dana C. , Derbyshire J. Andrew , McVeigh Elliot R.
Published: June 2003

The projection reconstruction (PR) trajectory was investigated for the effect of gradient timing delays between the actual and requested start time of each physical gradient. Radial trajectories constructed with delayed gradients miss the center of k‐space in an angularly dependent manner, causing effective echo times to vary with projection angle. The gradient timing delays were measured in phantoms, revealing delays on the x, y, and z gradients which differed by as much as 5 μsec. Using this one‐time calibration measurement, the trajectories were corrected for gradient delays by addition of compensatory gradient areas to the prephasers of the logical x and y readout gradients. Effective projection‐to‐projection echo time variability was reduced to less than 1 μsec for all imaging orientations. Using corrected trajectories, artifacts were reduced in phantom images and in volunteer studies. This correction should potentiate greater clinical use of the PR trajectory. Magn Reson Med 50:1–6, 2003. Published 2003 Wiley‐Liss, Inc.
Measuring the effects of indomethacin on changes in cerebral oxidative metabolism and cerebral blood flow during sensorimotor activation
Authors: St. Lawrence K.S. , Ye F.Q. , Lewis B.K. , Frank J.A. , McLaughlin A.C.
Published: June 2003

The work presented here uses combined blood oxygenation level‐dependent (BOLD) and arterial spin tagging (AST) approaches to study the effect of indomethacin on cerebral blood flow (CBF) and oxygen consumption (CMRO2) increases during motor activation. While indomethacin reduced the CBF increase during activation, it did not significantly affect the CMRO2 increase during activation. The ratio of the activation‐induced CBF increase in the presence and absence of indomethacin was 0.54 ± 0.08 (±SEM, n = 8, P < 0.001), while the ratio of the CMRO2 increase in the presence and absence of the drug was 1.02 ± 0.08 (±SEM, N = 8, ns). Potential difficulties in estimating CMRO2 changes from combined BOLD/AST data are discussed. Magn Reson Med 50:99–106, 2003. Published 2003 Wiley‐Liss, Inc.