1
|
Khan D, Sagar S, Jaleel J, Umar M, Tripathi M, Tripathi M, Sharma MC, Bal C. SISCOS in focal cortical dysplasia: localization and comparative analysis with MRI. Neuroradiology 2024:10.1007/s00234-024-03434-8. [PMID: 39060800 DOI: 10.1007/s00234-024-03434-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 07/18/2024] [Indexed: 07/28/2024]
Abstract
PURPOSE This study evaluates the efficacy of SISCOS (Subtraction ictal-interictal SPECT coregistered to SPECT) in localizing the epileptogenic zone (EZ) in focal cortical dysplasia (FCD), comparing its predictive performance with MRI and post-surgical outcomes based on ILAE classification. METHODS 84 patients with drug refractory epilepsy (DRE) who were operated and had histopathology consistent with FCD, were included in the study. All patients had undergone a complete work-up including SISCOS and MRI for EZ localization, followed by discussion in the multidisciplinary epilepsy surgery meeting prior to surgery. Ictal & interictal perfusion SPECT studies were performed with Tc-99 m Ethylene Cysteinate Dimer (Tc-99 m ECD) followed by SISCOS analysis using SPM2 and Bioimage Suite 2.6. Concordance for localization was determined by comparing with the surgical resection site and post-surgical outcomes were assessed using the ILAE classification. RESULTS The concordance for EZ localization demonstrated by SISCOS was 73.8% and MRI was 82.1%. 52 patients (61.9%) had good surgical outcome and 31(59%) of these were FCD type 2. In patients with discordant MRI findings, SISCOS was able to provide localisation in 86% (13/15), with 69.2% showing good surgical outcomes. Sensitivity of SISCOS and MRI was 73% (95% CI = 59-84.8%) and 78% (95% CI = 67.5-90.3%) respectively with no significant difference between the two. In FCD type I, both SISCOS and MRI revealed a similar a sensitivity of 76.4% (95%CI = 50.1-93.2%). Concordant cases exhibited higher seizure-free odds ratios for both modalities. CONCLUSION SISCOS is effective in localizing the EZ in FCD patients, comparable to MRI. Integrating SISCOS and MRI enhances lesion detection, especially in MRI discordant cases. A comprehensive diagnostic approach utilizing SISCOS and MRI can optimize the non-invasive pre-surgical assessment in DRE thereby guiding surgical decision-making in a resource-limited setting.
Collapse
Affiliation(s)
- Dikhra Khan
- Department of Nuclear Medicine, PET/CT, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Sambit Sagar
- Department of Nuclear Medicine, PET/CT, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Jasim Jaleel
- Department of Nuclear Medicine, PET/CT, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Mohammad Umar
- Department of Nuclear Medicine, PET/CT, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Madhavi Tripathi
- Department of Nuclear Medicine, PET/CT, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Manjari Tripathi
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India
| | - M C Sharma
- Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
| | - Chandrasekhar Bal
- Department of Nuclear Medicine, PET/CT, All India Institute of Medical Sciences, New Delhi, 110029, India
| |
Collapse
|
2
|
Bal CS, Tripathi M, Khan D. Gamma camera imaging in epilepsy. Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00194-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
3
|
Ferrando R, Damian A. Brain SPECT as a Biomarker of Neurodegeneration in Dementia in the Era of Molecular Imaging: Still a Valid Option? Front Neurol 2021; 12:629442. [PMID: 34040574 PMCID: PMC8141564 DOI: 10.3389/fneur.2021.629442] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 04/06/2021] [Indexed: 12/21/2022] Open
Abstract
Biomarkers are playing a progressively leading role in both clinical practice and scientific research in dementia. Although amyloid and tau biomarkers have gained ground in the clinical community in recent years, neurodegeneration biomarkers continue to play a key role due to their ability to identify different patterns of brain involvement that sign the transition between asymptomatic and symptomatic stages of the disease with high sensitivity and specificity. Both 18F-FDG positron emission tomography (PET) and perfusion single photon emission computed tomography (SPECT) have proved useful to reveal the functional alterations underlying various neurodegenerative diseases. Although the focus of nuclear neuroimaging has shifted to PET, the lower cost and wider availability of SPECT make it a still valid alternative for the study of patients with dementia. This review discusses the principles of both techniques, compares their diagnostic performance for the diagnosis of neurodegenerative diseases and highlights the role of SPECT to characterize patients from low- and middle-income countries, where special care of additional costs is particularly needed to meet the new recommendations for the diagnosis and characterization of patients with dementia.
Collapse
Affiliation(s)
- Rodolfo Ferrando
- Centro de Medicina Nuclear e Imagenología Molecular, Hospital de Clínicas, Universidad de la República (UdelaR), Montevideo, Uruguay.,Centro Uruguayo de Imagenología Molecular (CUDIM), Montevideo, Uruguay
| | - Andres Damian
- Centro de Medicina Nuclear e Imagenología Molecular, Hospital de Clínicas, Universidad de la República (UdelaR), Montevideo, Uruguay.,Centro Uruguayo de Imagenología Molecular (CUDIM), Montevideo, Uruguay
| |
Collapse
|
4
|
Chatterjee K, Carman-Esparza CM, Munson JM. Methods to measure, model and manipulate fluid flow in brain. J Neurosci Methods 2020; 333:108541. [PMID: 31838183 PMCID: PMC7607555 DOI: 10.1016/j.jneumeth.2019.108541] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 12/01/2019] [Accepted: 12/04/2019] [Indexed: 01/15/2023]
Abstract
The brain consists of a complex network of cells and matrix that is cushioned and nourished by multiple types of fluids: cerebrospinal fluid, blood, and interstitial fluid. The movement of these fluids through the tissues has recently gained more attention due to implications in Alzheimer's Disease and glioblastoma. Therefore, methods to study these fluid flows are necessary and timely for the current study of neuroscience. Imaging modalities such as magnetic resonance imaging have been used clinically and pre-clinically to image flows in healthy and diseased brains. These measurements have been used to both parameterize and validate models of fluid flow both computational and in vitro. Both of these models can elucidate the changes to fluid flow that occur during disease and can assist in linking the compartments of fluid flow with one another, a difficult challenge experimentally. In vitro models, though in limited use with fluid flow, allow the examination of cellular responses to physiological flow. To determine causation, in vivo methods have been developed to manipulate flow, including both physical and pharmacological manipulations, at each point of fluid movement of origination resulting in exciting findings in the preclinical setting. With new targets, such as the brain-draining lymphatics and glymphatic system, fluid flow and tissue drainage within the brain is an exciting and growing research area. In this review, we discuss the methods that currently exist to examine and test hypotheses related to fluid flow in the brain as we attempt to determine its impact on neural function.
Collapse
Affiliation(s)
- Krishnashis Chatterjee
- Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Cora M Carman-Esparza
- Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Jennifer M Munson
- Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States.
| |
Collapse
|
5
|
Abstract
Traumatic brain injury (TBI) is a major cause of death and disability, and therefore an important health and socioeconomic problem for our society. Individuals surviving from a moderate to severe TBI frequently suffer from long-lasting cognitive deficits. Such deficits include different aspects of cognition such as memory, attention, executive functions, and awareness of their deficits. This chapter presents a review of the main neuropsychological and neuroimaging studies of patients with TBI. These studies found that patients evolve differently according to the severity of the injury, the mechanism causing the injury, and the lesion location. Further research is necessary to develop rehabilitation methods that enhance brain plasticity and recovery after TBI. In this chapter, we summarize current knowledge and controversies, focusing on cognitive sequelae after TBI. Recommendations from the Common Data Elements are provided, with an emphasis on diagnosis, outcome measures, and studies organization to make data more comparable across studies. Final considerations on neuroimaging advances, rehabilitation approaches, and genetics are described in the final section of the chapter.
Collapse
Affiliation(s)
- Irene Cristofori
- Cognitive Neuroscience Laboratory, Rehabilitation Institute of Chicago, Chicago, IL, USA
| | - Harvey S Levin
- Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX, USA.
| |
Collapse
|
6
|
|
7
|
Rostami E, Engquist H, Enblad P. Imaging of cerebral blood flow in patients with severe traumatic brain injury in the neurointensive care. Front Neurol 2014; 5:114. [PMID: 25071702 PMCID: PMC4083561 DOI: 10.3389/fneur.2014.00114] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/16/2014] [Indexed: 12/21/2022] Open
Abstract
Ischemia is a common and deleterious secondary injury following traumatic brain injury (TBI). A great challenge for the treatment of TBI patients in the neurointensive care unit (NICU) is to detect early signs of ischemia in order to prevent further advancement and deterioration of the brain tissue. Today, several imaging techniques are available to monitor cerebral blood flow (CBF) in the injured brain such as positron emission tomography (PET), single-photon emission computed tomography, xenon computed tomography (Xenon-CT), perfusion-weighted magnetic resonance imaging (MRI), and CT perfusion scan. An ideal imaging technique would enable continuous non-invasive measurement of blood flow and metabolism across the whole brain. Unfortunately, no current imaging method meets all these criteria. These techniques offer snapshots of the CBF. MRI may also provide some information about the metabolic state of the brain. PET provides images with high resolution and quantitative measurements of CBF and metabolism; however, it is a complex and costly method limited to few TBI centers. All of these methods except mobile Xenon-CT require transfer of TBI patients to the radiological department. Mobile Xenon-CT emerges as a feasible technique to monitor CBF in the NICU, with lower risk of adverse effects. Promising results have been demonstrated with Xenon-CT in predicting outcome in TBI patients. This review covers available imaging methods used to monitor CBF in patients with severe TBI.
Collapse
Affiliation(s)
- Elham Rostami
- Section of Neurosurgery, Department of Neuroscience, Uppsala University , Uppsala , Sweden ; Department of Neuroscience, Karolinska Institutet , Stockholm , Sweden
| | - Henrik Engquist
- Department of Surgical Sciences, Anaesthesiology and Intensive Care, Uppsala University , Uppsala , Sweden
| | - Per Enblad
- Section of Neurosurgery, Department of Neuroscience, Uppsala University , Uppsala , Sweden
| |
Collapse
|
8
|
Dhandapani S, Sharma A, Sharma K, Das L. Comparative evaluation of MRS and SPECT in prognostication of patients with mild to moderate head injury. J Clin Neurosci 2014; 21:745-50. [DOI: 10.1016/j.jocn.2013.07.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 06/22/2013] [Accepted: 07/04/2013] [Indexed: 02/08/2023]
|
9
|
Abstract
Epilepsy is a common neurological disorder with diverse etiologies. Neuroimaging plays an important role in workup of patients with epilepsy. It helps to identify brain pathologies that require specific treatment; and also in formulating syndromic and etiological diagnoses so as to give patients and their relatives an accurate prognosis. Magnetic resonance imaging, specially the 3 tesla MRI is the imaging of choice because of its ability to detect small lesions like mesial temporal sclerosis, cortical dysplasias, small tumors, etc that are not detected by conventional MR or CT scan of brain. Identification of these lesions often helps in managing refractory epilepsies more effectively. However, cost and non-availability of MR in large part of the country necessitate the use of CT as an alternative. CT is often the initial investigation and also useful in acute situations. Functional imagings are used for pre-surgical work-up of refractory epilepsy cases with an aim to identify the epileptogenic focus and to delineate functional areas nearing the focus.
Collapse
Affiliation(s)
- Trishit Roy
- Department of Neurology, Bangur Institute of Neuroscience and Psychiatry, 52/1A, S.N. Pandit Street, Kolkata, India
| | | |
Collapse
|
10
|
Cummings JL. Biomarkers in Alzheimer's disease drug development. Alzheimers Dement 2011; 7:e13-44. [PMID: 21550318 DOI: 10.1016/j.jalz.2010.06.004] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 06/01/2010] [Accepted: 06/03/2010] [Indexed: 12/27/2022]
Abstract
Developing new therapies for Alzheimer's disease (AD) is critically important to avoid the impending public health disaster imposed by this common disorder. Means must be found to prevent, delay the onset, or slow the progression of AD. These goals will be achieved by identifying disease-modifying therapies and testing them in clinical trials. Biomarkers play an increasingly important role in AD drug development. In preclinical testing, they assist in decisions to develop an agent. Biomarkers in phase I provide insights into toxic responses and drug metabolism and in Phase II proof-of-concept trials they facilitate go/no-go decisions and dose finding. Biomarkers can play a role in identifying presymptomatic patients or specific patient subgroups. They can provide evidence of target engagement before clinical changes can be expected. Brain imaging can serve as a primary outcome in Phase II trials and as a key secondary outcome in Phase III trials. Magnetic resonance imaging is currently best positioned for use in large multicenter clinical trials. Cerebrospinal fluid (CSF) measures of amyloid beta protein (Aβ), tau protein, and hyperphosphorylated tau (p-tau) protein are sensitive and specific to the diagnosis of AD and may serve as inclusion criteria and possibly as outcomes in clinical trials targeting relevant pathways. Plasma measures of Aβ are of limited diagnostic value but may provide important information as a measure of treatment response. A wide variety of measures of detectable products of cellular processes are being developed as possible biomarkers accessible in the cerebrospinal fluid and plasma or serum. Surrogate markers that can function as outcomes in pivotal trials and reliably predict clinical outcomes are needed to facilitate primary prevention trials of asymptomatic persons where clinical measures may be of limited value. Fit-for-purpose biomarkers are increasingly available to guide AD drug development decisions.
Collapse
Affiliation(s)
- Jeffrey L Cummings
- Cleveland Clinic Lou Ruvo Center for Brain Health, Cleveland Clinic Neurological Institute, Las Vegas, NV, USA.
| |
Collapse
|
11
|
|
12
|
Molecular SPECT Imaging: An Overview. INTERNATIONAL JOURNAL OF MOLECULAR IMAGING 2011; 2011:796025. [PMID: 21603240 PMCID: PMC3094893 DOI: 10.1155/2011/796025] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Accepted: 02/05/2011] [Indexed: 12/15/2022]
Abstract
Molecular imaging has witnessed a tremendous change over the last decade. Growing interest and emphasis are placed on this specialized technology represented by developing new scanners, pharmaceutical drugs, diagnostic agents, new therapeutic regimens, and ultimately, significant improvement of patient health care. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) have their signature on paving the way to molecular diagnostics and personalized medicine. The former will be the topic of the current paper where the authors address the current position of the molecular SPECT imaging among other imaging techniques, describing strengths and weaknesses, differences between SPECT and PET, and focusing on different SPECT designs and detection systems. Radiopharmaceutical compounds of clinical as well-preclinical interest have also been reviewed. Moreover, the last section covers several application, of μSPECT imaging in many areas of disease detection and diagnosis.
Collapse
|
13
|
Haacke EM, Duhaime AC, Gean AD, Riedy G, Wintermark M, Mukherjee P, Brody DL, DeGraba T, Duncan TD, Elovic E, Hurley R, Latour L, Smirniotopoulos JG, Smith DH. Common data elements in radiologic imaging of traumatic brain injury. J Magn Reson Imaging 2011; 32:516-43. [PMID: 20815050 DOI: 10.1002/jmri.22259] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Traumatic brain injury (TBI) has a poorly understood pathology. Patients suffer from a variety of physical and cognitive effects that worsen as the type of trauma worsens. Some noninvasive insights into the pathophysiology of TBI are possible using magnetic resonance imaging (MRI), computed tomography (CT), and many other forms of imaging as well. A recent workshop was convened to evaluate the common data elements (CDEs) that cut across the imaging field and given the charge to review the contributions of the various imaging modalities to TBI and to prepare an overview of the various clinical manifestations of TBI and their interpretation. Technical details regarding state-of-the-art protocols for both MRI and CT are also presented with the hope of guiding current and future research efforts as to what is possible in the field. Stress was also placed on the potential to create a database of CDEs as a means to best record information from a given patient from the reading of the images.
Collapse
Affiliation(s)
- E Mark Haacke
- Department of Radiology and Biomedical Engineering, Wayne State University, Detroit, Michigan 48201, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Dhandapani SS, Sharma A, Rajan SK, Chand K, Das L. Single photon emission computed tomography evaluation in patients with mild to moderate head injury. INDIAN JOURNAL OF NEUROTRAUMA 2010. [DOI: 10.1016/s0973-0508(10)80024-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
15
|
Franc BL, Acton PD, Mari C, Hasegawa BH. Small-Animal SPECT and SPECT/CT: Important Tools for Preclinical Investigation. J Nucl Med 2008; 49:1651-63. [DOI: 10.2967/jnumed.108.055442] [Citation(s) in RCA: 180] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
|
16
|
|
17
|
Van Heertum RL, Ichise M. Brain. Clin Nucl Med 2007. [DOI: 10.1007/978-3-540-28026-2_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
18
|
N. Maiti S, P. Kamalesh Babu R. Norepinephrine Reuptake Inhibitors for Depression, ADHD and Other Neuropsychiatric Disorders. HETEROCYCLES 2006. [DOI: 10.3987/rev-06-sr(o)1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
19
|
Shah K, Weissleder R. Molecular optical imaging: applications leading to the development of present day therapeutics. NeuroRx 2005; 2:215-25. [PMID: 15897946 PMCID: PMC1064987 DOI: 10.1602/neurorx.2.2.215] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A number of advances in the molecular imaging field have led to the sensing of specific molecular targets and pathways in living animals. In the optical imaging field, these include the designing of biocompatible near-infrared fluorochromes, development of targeted and activatable "smart" imaging probes, and engineering of activatable fluorescent and bioluminescent proteins. The current advances in molecular optical imaging will help in early disease diagnoses, functioning of a number of pathways and finally help speed drug discovery. In this review, we will describe the near infrared fluorescent and bioluminescence imaging modalities and how these techniques have been employed in current research. Furthermore, we will also shed some light on the use of these imaging modalities in neurotherapeutics, for example imaging different parameters of vector-mediated gene expression in glioma tumors and stem cell tracking in vivo.
Collapse
Affiliation(s)
- Khalid Shah
- Center for Molecular Imaging Research, Massachusetts General Hospital, MA 02129, USA.
| | | |
Collapse
|
20
|
Abstract
In this review, we discuss the role of neuroimaging in assessing treatment options for movement disorders, particularly Parkinson's disease (PD). Imaging methods to assess dopaminergic function have recently been applied in trials of potential neuroprotective agents. Other imaging methods using regional metabolism and/or cerebral perfusion have been recently introduced to quantify the modulation of network activity as an objective marker of the treatment response. Both imaging strategies have provided novel insights into the mechanisms underlying a variety of pharmacological and stereotaxic surgical treatment strategies for PD and other movement disorders.
Collapse
Affiliation(s)
- Thomas Eckert
- Department of Neurology II and Psychiatry, University of Magdeburg, Germany
| | | |
Collapse
|
21
|
Molecular optical imaging: applications leading to the development of present day therapeutics. NeuroRx 2005. [PMID: 15897946 DOI: 10.1007/bf03206667] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
Abstract
A number of advances in the molecular imaging field have led to the sensing of specific molecular targets and pathways in living animals. In the optical imaging field, these include the designing of biocompatible near-infrared fluorochromes, development of targeted and activatable "smart" imaging probes, and engineering of activatable fluorescent and bioluminescent proteins. The current advances in molecular optical imaging will help in early disease diagnoses, functioning of a number of pathways and finally help speed drug discovery. In this review, we will describe the near infrared fluorescent and bioluminescence imaging modalities and how these techniques have been employed in current research. Furthermore, we will also shed some light on the use of these imaging modalities in neurotherapeutics, for example imaging different parameters of vector-mediated gene expression in glioma tumors and stem cell tracking in vivo.
Collapse
|
22
|
Dickerson BC, Sperling RA. Neuroimaging biomarkers for clinical trials of disease-modifying therapies in Alzheimer's disease. NeuroRx 2005; 2:348-60. [PMID: 15897955 PMCID: PMC1064996 DOI: 10.1602/neurorx.2.2.348] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The pathophysiologic process leading to neurodegeneration in Alzheimer's disease (AD) is thought to begin long before clinical symptoms develop. Existing therapeutics for AD improve symptoms, but increasing efforts are being directed toward the development of therapies to impede the pathologic progression of the disease. Although these medications must ultimately demonstrate efficacy in slowing clinical decline, there is a critical need for biomarkers that will indicate whether a candidate disease-modifying therapeutic agent is actually altering the underlying degenerative process. A number of in vivo neuroimaging techniques, which can reliably and noninvasively assess aspects of neuroanatomy, chemistry, physiology, and pathology, hold promise as biomarkers. These neuroimaging measures appear to relate closely to neuropathological and clinical data, such as rate of cognitive decline and risk of future decline. As this work has matured, it has become clear that neuroimaging measures may serve a variety of potential roles in clinical trials of candidate neurotherapeutic agents for AD, depending in part on the question of interest and phase of drug development. In this article, we review data related to the range of neuroimaging biomarkers of Alzheimer's disease and consider potential applications of these techniques to clinical trials, particularly with respect to the monitoring of disease progression in trials of disease-modifying therapies.
Collapse
Affiliation(s)
- Bradford C Dickerson
- Department of Neurology and the Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.
| | | |
Collapse
|
23
|
Abstract
Neuroimaging has important applications in the diagnosis and treatment of patients with seizures and epilepsy. Having replaced computed tomography (CT) in many situations, MRI is the preferred imaging technique for patients with epilepsy. Advances in radionuclide-based techniques such as single-photon emission CT/positron emission tomography and electromagnetic source imaging with magnetoencephalography are providing new insights into the pathophysiology of epilepsy. In addition, techniques such as magnetic resonance spectroscopy are beginning to impact treatment. In this review, I discuss how these techniques are used in clinical practice but more importantly, how imaging findings play an increasing role in neurotherapeutics.
Collapse
Affiliation(s)
- Ruben I Kuzniecky
- New York University Epilepsy Center, Department of Neurology, New York University School of Medicine, New York, New York 10016, USA
| |
Collapse
|
24
|
Pirko I, Fricke ST, Johnson AJ, Rodriguez M, Macura SI. Magnetic resonance imaging, microscopy, and spectroscopy of the central nervous system in experimental animals. NeuroRx 2005; 2:250-64. [PMID: 15897949 PMCID: PMC1064990 DOI: 10.1602/neurorx.2.2.250] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Over the last two decades, microscopic resolution in vivo magnetic resonance imaging (MRI) techniques have been developed and extensively used in the study of animal models of human diseases. Standard MRI methods are frequently used in clinical studies and in the general clinical practice of human neurological diseases. This generates a need for similar studies in experimental animal research. Because small rodents are the most commonly used species as animal models of neurological diseases, the MRI techniques need to be able to provide microscopic resolution and high signal-to-noise ratio images in relatively short time. Small animal MRI systems use very high field-strength magnets, which results in higher signal to noise ratio; however, the contrast characteristics of live tissue are different at these field strengths. In addition to standard MRI techniques, several new applications have been implemented in experimental animals, including diffusion and perfusion studies, MR angiography, functional MRI studies, MRI tractography, proton and phosphorous spectroscopy, cellular and molecular imaging using novel contrast methods. Here we give an overview of how to establish a small animal imaging facility with the goal of CNS imaging. We describe the basic physical processes leading to MR signal generation, highlighting the differences between standard clinical MRI and small animal MRI. Finally, typical findings in the most common neurological disease categories and novel MRI/magnetic resonance spectroscopy methods used in their study are also described.
Collapse
Affiliation(s)
- Istvan Pirko
- University of Cincinnati, Department of Neurology, Cincinnati, Ohio 45267, USA.
| | | | | | | | | |
Collapse
|
25
|
Abstract
Magnetic resonance imaging (MRI) plays an ever-expanding role in the evaluation of multiple sclerosis (MS). This includes its sensitivity for the diagnosis of the disease and its role in identifying patients at high risk for conversion to MS after a first presentation with selected clinically isolated syndromes. In addition, MRI is a key tool in providing primary therapeutic outcome measures for phase I/II trials and secondary outcome measures in phase III trials. The utility of MRI stems from its sensitivity to longitudinal changes including those in overt lesions and, with advanced MRI techniques, in areas affected by diffuse occult disease (the so-called normal-appearing brain tissue). However, all current MRI methodology suffers from limited specificity for the underlying histopathology. Conventional MRI techniques, including lesion detection and measurement of atrophy from T1- or T2-weighted images, have been the mainstay for monitoring disease activity in clinical trials, in which the use of gadolinium with T1-weighted images adds additional sensitivity and specificity for areas of acute inflammation. Advanced imaging methods including magnetization transfer, fluid attenuated inversion recovery, diffusion, magnetic resonance spectroscopy, functional MRI, and nuclear imaging techniques have added to our understanding of the pathogenesis of MS and may provide methods to monitor therapies more sensitively in the future. However, these advanced methods are limited by their cost, availability, complexity, and lack of validation. In this article, we review the role of conventional and advanced imaging techniques with an emphasis on neurotherapeutics.
Collapse
Affiliation(s)
- Rohit Bakshi
- Department of Neurology and Radiology, Partners MS Center, Center for Neurological Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
| | | | | | | |
Collapse
|