Imaging In Movement Disorders Research Articles

Magnetic Resonance Imaging in Movement Disorders: A Guide for Clinicians and Scientists

P. Tuite and A. Dagher, Eds. New York, NY: Cambridge University Press, 2013, 291 pages, $150 Magnetic Resonance Imaging in Movement Disorders is a useful guide for general readers, including nuclear medicine physicians, who may not be experts in the various MR imaging technologies. This well-

Parenchymal imaging in movement disorders.

The use of B-mode sonography in neurological diagnosis was once considered of limited importance due to the barrier of the skull. However, modern ultrasound systems allow visualization of the brain parenchyma with a high degree of accuracy. Transcranial sonography (TCS) can offer unique information on brain tissue pathology, as it uses different physical principles for imaging acquisition than do other neuroimaging techniques. The method is harmless, is quick to perform at low cost and demands no sedation. The main limitations of this technique are dependence on the quality of the individual bone window and on proper operator training. A huge body of research has shown that patients with Parkinson's disease (PD) display an enlarged hyperechogenic substantia nigra by TCS with a positive predictive value of 92.9%. Healthy individuals (8-15%) may show the same marker, in some cases correlating with decreased striatal dopamine uptake, motor slowing and prodromal markers of PD, indicating that this ultrasound sign may constitute a risk marker for PD. Other movement disorder diagnoses, although less extensively studied for TCS, may benefit from using this method as a supplementary diagnostic tool. This review provides a summary of the typical TCS findings and their value in the differential diagnosis of some movement disorders.

The evolving role of diffusion magnetic resonance imaging in movement disorders.

Significant advances have allowed diffusion magnetic resonance imaging (MRI) to evolve into a powerful tool in the field of movement disorders that can be used to study disease states and connectivity between brain regions. Diffusion MRI is a promising potential biomarker for Parkinson's disease and other forms of parkinsonism, and may allow the distinction of different forms of parkinsonism. Techniques such as tractography have contributed to our current thinking regarding the pathophysiology of dystonia and possible mechanisms of penetrance. Diffusion MRI measures could potentially assist in monitoring disease progression in Huntington's disease, and in uncovering the nature of the processes and structures involved the development of essential tremor. The ability to represent structural connectivity in vivo also makes diffusion MRI an ideal adjunctive tool for the surgical treatment of movement disorders. We review recent studies using diffusion MRI in movement disorders research and present the current state of the science as well as future directions.

Milestones in magnetic resonance imaging and transcranial sonography of movement disorders

Twenty-five years ago, when this journal was initiated, imaging of movement disorders was in its infancy. Since that time, magnetic resonance imaging has become a standard technique that is routinely performed in patients with movement disorders in order to exclude secondary causes and in some instances to provide specific information that aids in making the diagnosis of a neurodegenerative condition. Transcranial sonography is a more recent advance and is now widely employed to aid in the diagnosis of Parkinson's disease and possibly in detecting individuals in the premotor phases of the disease. Investigations are currently under way to evaluate the value of this technique in other movement disorders.

Diffusion Tensor Imaging in Movement Disorders: Review of Major Patterns and Correlation with Normal Brainstem/cerebellar White Matter

The authors reviewed the diffusion tensor imaging (DTI) and tractography (DTT) of the normal brainstem and cerebellar white matter in normal volunteers, correlating it with structural magnetic resonance (MR) imaging and DTI data obtained in patients evaluated in our institution with movement disorders, including multisystem atrophy (MSA), spinocerebellar ataxia (SCA), progressive supra-nuclear palsy (PSP) and idiopathic Parkinson's disease (PD). DTI and tractography data demonstrated major white-matter fibers within the brain stem and cerebellum, including cortico-spinal tracts, transverse pontine fibers, medial lemniscus and cerebellar peduncles. Visualization of selective degeneration of these individual fibre tracts with DTI, in our cases, added qualitative data to the differential diagnosis of movement disorders.

Microglial Imaging in Movement Disorders With PK11195 PET

Activated microglia play a major role in the pathogenesis in neurological disorders. The transition of microglia from the normal resting state to the activated state is associated with an increased expression of receptors known as peripheral benzodiazepine binding sites, which are abundant on cells of mononuclear phagocyte lineage. PK11195 is a ligand which binds selectively to peripheral benzodiazepine binding sites, a type of receptor selectively expressed by activated microglia in the central nervous system. The 11 C-(R)-PK11195 positron emission tomography (PET) is already applied to many kinds of neurological disorders, including neurodegenerative disorders, and can demonstrate the role of neuroinflamma tion in the pathogenesis of neurological disorders. And this imaging modality also provides a means to monitor potential clinical relevance of antiinflammat ory treatm ent strategies in vivo. This article reviews some of the clinical applications of 11 C-(R)

Clinical use of dopamine transporter imaging in movement disorders: benefits of appropriate use

The role of dopamine transporter (DAT) imaging in the diagnostic work-up of patients with Parkinson’s disease (PD) and Parkinson-plus syndromes is the object of many studies by neurologists and neuroimaging specialists. The present scenario is portrayed by Scherfler and many other internationally renown experts in movement disorders in a review paper in which they point out that although the diagnosis of idiopathic PD (IPD) can be achieved with a high degree of accuracy in cases with full expression of classical clinical features, diagnostic uncertainty remains in early disease with subtle or ambiguous signs [1].

Cardiac sympathetic denervation imaging in movement disorders and dementias

The sympathetic nervous system greatly influences cardiovascular physiology, and the importance of cardiac innervation abnormalitiesinthephysiopathologyof variouscardiacdiseases has been emphasised. Cardiac neurotransmission imaging with single-photon-emission computed tomography (SPECT) allows in vivo assessment of the myocardial nervous system. At present, the most commonly used SPECT tracer to assess cardiac neurotransmission is metaiodobenzylguanidine labelled with iodine-123 ( 123 I-MIBG). Cardiac 123 I-MIBG scintigraphy allows autonomic neuropathy to be detected in the early stages of diabetes mellitus. In patients with heart failure, the assessment of cardiac sympathetic activity has important prognostic implications. Targeting neuronal dysfunction with 123 I-MIBG scintigraphy in patients with heart transplantation, ischaemic heart disease, hypertension, diabetes mellitus, heart failure, drug-induced cardiotoxicity and dysautonomias can contribute to early diagnosis, prognostic stratification and appropriate treatment [1]. However, this is not all of the uses for 123 I-MIBG, as an emerging application of this tracer is being pursued for studies in movement disorders.

Functional brain imaging of movement disorders

Functional brain imaging techniques such as positron emission tomography (PET) have contributed to our understanding of the pathophysiology of Parkinson’s disease (PD) and other movement disorders. PET employs small amounts of positron emitting radioligands to produce quantitative measures of physiological and biochemical processes in the brain and other organs. In a PET experiment, a subject is given a compound of biological interest. The spatial and temporal distribution of the radiotracer is measured quantitatively in the course of the PET study, providing a tomographic representation of regional radioactivity concentration. In this review, we focus on the potential application of PET in the selection of suitable candidates and the assessment of surgical interventions such as pallidotomy, thalamotomy, and deep brain stimulation. [Neurol Res 2000; 22: 305–312]