http://ee.sharif.edu/~miap/Files/A%20Survey%20of%20Medical%20Image%20Registration.pdf

A survey of medical image registration.

References http://genesdev.cshlp.org/content/17/5/545.full.html#related-urls Article cited in: http://genesdev.cshlp.org/content/17/5/545.full.html#ref-list-1 This article cites 228 articles, 79 of which can be accessed free at: service Email alerting click here top right corner of the article or Receive free email alerts when new articles cite this article sign up in the box at the Collections Topic (33 articles) Molecular Physiology and Metabolism  (98 articles) Cancer and Disease Models  Articles on similar topics can be found in the following collections

/pdf/molecular-imaging-in-living-subjects-seeing-fundamental-58mg35grjk.pdf

Molecular imaging in living subjects: seeing fundamental biological processes in a new light

An overview of the following six cortical zones that have been defined in the presurgical evaluation of candidates for epilepsy surgery is given: the symptomatogenic zone; the irritative zone; the seizure onset zone; the epileptogenic lesion; the epileptogenic zone; and the eloquent cortex. The stepwise historical evolution of these different zones is described. The current diagnostic techniques used in the definition of these cortical zones, such as video-EEG monitoring, MRI and ictal single photon emission computed tomography, are discussed. Established diagnostic tests are set apart from procedures that should still be regarded as experimental, such as magnetoencephalography, dipole source localization and spike-triggered functional MRI. Possible future developments that might lead to a more direct definition of the epileptogenic zone are presented.

/pdf/presurgical-evaluation-of-epilepsy-216chlpgp2.pdf

Presurgical evaluation of epilepsy.

A considerable amount of compelling evidence exists, predominantly from animal models and experimental paradigms, for the existence of specific cortical and subcortical networks in the genesis and expression of partialand generalized-onset seizures (1–13). My goal is to present the concept of human epilepsy as a disorder of large neural networks and to support through several lines of reasoning how applicable the observations from experimental models are to localization-related seizures in the human disorder. I do not attempt to define specifically every possible operational human network or even all the limits or components of those that I do address, but I hope to show in a compelling way that the evidence we already have is not consistent with any other explanation. This is a new way of understanding, diagnosing, and potentially treating the various forms of human epilepsy. In this context, I consider a network to be a functionally and anatomically connected, bilaterally represented, set of cortical and subcortical brain structures and regions in which activity in any one part affects activity in all the others. The essential operational component of this definition is the observation that vulnerability to seizure activity in any one part of the network is influenced by activity everywhere else in the network, and that the network as a whole is responsible for the clinical and electrographic phenomena that we associate with human seizures. Implicit in this idea is that the seizures may entrain this large neural network from any given part, such that it becomes irrelevant to discuss the “onset” of seizures in any specific part of the network. In other words, the electrical hyperexcitability associated with seizure activity reverberates within the neural structures of the network, which operate together and inextricably to culminate in the eventual expression of seizures. A singular concept is the distinction between the anatomic structures involved in seizure propagation, and those belonging to the neural network that underlies a specific patient’s epilepsy. The network structures are connected functionally and structurally; they are essential to the development of the seizure and thus the existence and maintenance of the epileptic disorder. Independently, seizures propagate in a variably extensive way that might involve any region or neural structure with anatomic connections to the primary seizure network; seizures can propagate to many more regions than those that are involved in the network. Important corollaries that derive from these ideas are that interruption of the network, in a structural sense, or modification of network activity by electrical, biochemical, or metabolic influences in any part of the network will alter seizure expression or its occurrence. The corollaries have the greatest implications for treatment, as we will see later. Based on extensive experience with a great number and diversity of human epilepsy patients with intractable seizures, I describe and support the evidence for three specific large human epilepsy networks. Many others are likely, but the data are not so extensive. The first is the network associated with the most common human intractable epilepsy, and the one about which we have the most information: the medial temporal/limbic network. The medial temporal/limbic network is bilateral, cortical, and subcortical, and includes the hippocampi, the amygdalae, the entorhinal cortices, lateral temporal neocortices, and extratemporal components of the medial thalamus and the inferior frontal lobes. The other two networks are less commonly identified, even in their component parts: the medial occipital/lateral temporal network and the superior parietal/medial frontal network. Two additional networks, for which evidence is highly suggestive, but which I do not discuss in detail, include the bifrontal/ pontine/subthalamic network and the parietal/medial temporal network. The lines of evidence that support the existence and importance of these networks in the genesis of human epilepsy are clinical observations, intracranial EEG, functional neuroimaging, anatomic observations, and the response of seizures to specific invasive treatments. Accepted December 7, 2001. Address correspondence and reprint requests to Dr. S.S. Spencer at Department of Neurology, Yale University School of Medicine, P.O. Box 208018, New Haven, CT 06520-8018, U.S.A. E-mail: susan.spencer@yale.edu Epilepsia, 43(3):219–227, 2002 Blackwell Publishing, Inc. © International League Against Epilepsy

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1528-1157.2002.26901.x

Neural networks in human epilepsy: evidence of and implications for treatment

Single photon-emission computed tomography

Imageprocessingtechniqueswere appliadto SPECTbrainim ages to aid inthe localization ofepilepticfod.Methods: Ictaland intedctalcerebralperfusionSPECTimageswere acquiredfrom 12 epilepsypatients(6temporal, 6 extratemporal) afterinjection of20 mCiÂ°@Fc-HMPAO. E@h @at scanwas registered tothe same patient'sinterictalscan. Normalization ofthe three-dimen atonaldata was appliedto accountfor globalpercent brainup take and total injectedactMty.Afterregistration,normalization and subtractionofthe SPECTimegesand functionaldifference images were computed. D@erenceimeges were calcu@ed, whichgivea quantitativemeasureofperfusionalterationsduring ictus.The resultingdifferenceimageswere also registeredwith eech pabent@s MRIscan whichpermitslocalization of perfusion changes ontoanatomicalstructures.Results: Areasinthe brain wheresignificantperfusionincreases occurcorrelatewithareas confirmedto be seizurefoci.Fourofthe six patientswithknown temporal lobe seizure foci ethibfted significantperfusion in creases on the differenceimages.These areas demonstratea percentincreaseofperfusionlargerthan40%.Forthe extratem poral seizure patients,four of the four confirmedseizure sites were diagnosedwithdifferenceimages.Resultson the remain ing two patients were incondunive.Condusion: When com paredto side-by-sidevisualinterpretation ofthe ictaland inteiic tat SPECT images, registrationof SPECT and MR images togetherwithcalculateddifferencemaps greatlyenhances the abilityto localize epleptic seizure foci. This offers the potential to locate epilepticseizure foci using a noninvasive,inexpensive imaging procedure and data processing algodthm.

http://jnm.snmjournals.org/content/36/4/684.full.pdf

Difference Images Calculated from Ictal and Interictal Technetium-99m-HMPAO SPECT Scans of Epilepsy

True ictal SPECT can accurately demonstrate perfusion increases in the epileptogenic area but often requires dedicated personnel waiting at the bedside to accomplish the injection. We investigated the value of perfusion changes as measured by ictal or immediate postictal SPECT in localizing the epileptogenic region in refractory partial epilepsy. Methods: Quantitative perfusion difference images were calculated by registering, normalizing and subtracting ictal (or immediate postictal) from interictal SPECT for 53 patients with refractory epilepsy. Perfusion difference SPECT results were compared with visually interpreted SPECT, scalp electroencephalography (EEG), MRI, PET and intracranial EEG. Results: In 43 patients (81%), discrete areas of increased perfusion (with ictal injections) or decreased perfusion (with postictal injections) were noted. Interictal scalp EEG was localizing in 28 patients (53%), ictal scalp EEG was localizing in 35 patients (66%) and intracranial EEG was localizing in 22 patients (85%) (of 26 patients who underwent invasive study). MRI was localizing in 34 patients (64%), PET was localizing in 32 of 45 patients (71%), interictal SPECT was localizing in 26 patients (49%) and peri-ictal SPECT (visual interpretation) was localizing in 30 patients (57%). By comparison with an intracranial EEG standard of localization, SPECT subtraction analysis had 86% sensitivity and 75% specificity. Conclusion: Our data provide evidence that SPECT perfusion difference analysis has higher sensitivity and specificity than any other noninvasive localizing criterion and can localize epileptogenic regions with accuracy comparable with that of intracranial EEG. To obtain these results, one must apply knowledge of the timing of the ictal injection relative to seizure occurrence.

https://jnm.snmjournals.org/content/jnumed/40/5/730.full.pdf

Sensitivity and specificity of quantitative difference SPECT analysis in seizure localization.

Yohimbine alters regional cerebral blood flow in panic disorder

UNLABELLED The purposes of this study were to develop a method for nonuniform attenuation correction of 123I emission brain images based on transmission imaging with a longer-lived isotope (i.e., 57Co) and to evaluate the relative improvement in quantitative SPECT images achieved with nonuniform attenuation correction. METHODS Emission and transmission SPECT scans were acquired on three different sets of studies: a heterogeneous brain phantom filled with 1231 to simulate the distribution of dopamine transporters labeled with 2beta-carbomethoxy-3beta-(4-123I-iodophenyl)tropane (123I-beta-CIT); nine healthy human control subjects who underwent transmission scanning using two separate line sources (57Co and 123I); and a set of eight patients with Parkinson's disease and five healthy control subjects who received both emission and transmission scans after injection of 123I-beta-CIT. Attenuation maps were reconstructed using a Bayesian transmission reconstruction algorithm, and attenuation correction was performed using Chang's postprocessing method. The spatial distribution of errors within the brain was obtained from attenuation correction factors computed from uniform and nonuniform attenuation maps and was visualized on a pixel-by-pixel basis as an error image. RESULTS For the heterogeneous brain phantom, the uniform attenuation correction had errors of 2%-6.5% for regions corresponding to striatum and background, whereas nonuniform attenuation correction was within 1%. Analysis of 123I transmission images of the nine healthy human control subjects showed differences between uniform and nonuniform attenuation correction to be in the range of 6.4%-16.0% for brain regions of interest (ROIs). The human control subjects who received transmission scans only were used to generate a curvilinear function to convert 57Co attenuation values into those for 123I, based on a pixel-by-pixel comparison of two coregistered transmission images for each subject. These values were applied to the group of patients and healthy control subjects who received transmission 57Co scans and emission 123I scans after injection of 123I-beta-CIT. In comparison to nonuniform attenuation correction as the gold standard, uniform attenuation with the ellipse drawn around the transmission image caused an approximately 5% error, whereas placement of the ellipse around the emission image caused a 15% error. CONCLUSION Nonuniform attenuation correction allowed a moderate improvement in the measurement of absolute activity in individual brain ROIs. When images were analyzed as target-to-background activity ratios, as is commonly performed with 123I-beta-CIT, these outcome measures showed only small differences when Parkinson's disease patients and healthy control subjects were compared using nonuniform, uniform or even no attenuation correction.

https://jnm.snmjournals.org/content/jnumed/39/10/1719.full.pdf

Significance of Nonuniform Attenuation Correction in Quantitative Brain SPECT Imaging

Naloxone (0.8 mg, s.c.) effects on opiate withdrawal signs and symptoms and regional brain function were assessed in 10 methadone-maintained patients and 10 healthy subjects in a double-blind, placebo-controlled study. Regional brain function was assessed using single photon emission computerized tomography (SPECT) by evaluating the uptake of [99mTc]d,l-hexamethylpropyleneamine oxime (HMPAO) in the brain, a process related to regional cerebral perfusion. Comparisons of patients and healthy subjects after saline infusion suggested that chronic opiate dependence was associated with lower corrected activity ratios (regional count density/whole brain count density) in frontal and parietal cortices and greater activity ratios in the thalamus. Opiate-dependent patients, but not healthy subjects, developed opiate withdrawal signs and symptoms after naloxone administration. Following naloxone administration, patients undergoing opiate withdrawal exhibited lower whole brain count density than healthy subjects. They also had lower activity ratios in frontal and parietal cortices and increased thalamic activity ratios relative to healthy subjects receiving naloxone. Naloxone administration in healthy subjects, but not opiate withdrawal in patients, was associated with decreased right parietal cortex and increased right temporal cortex and left basal ganglia activity ratios. Relative to naloxone effects in healthy subjects, opiate withdrawal was associated with decreased whole brain count density and a reduced right temporal cortex activity ratio. This preliminary study reports an initial evaluation of HMPAO-SPECT imaging for assessing regional alterations in brain function during opiate dependence and withdrawal. While group differences were reported, the small magnitude of regional alterations in patients undergoing opiate withdrawal raised concern that HMPAO-SPECT methods employed were inadequate for assessing human regional brain function during phases of opiate addiction. Other emerging functional brain imaging technologies should be evaluated relative to improved HMPAO-SPECT methods for this purpose.

Zubal Ig

Papers

Difference Images Calculated from Ictal and Interictal Technetium-99m-HMPAO SPECT Scans of Epilepsy

Sensitivity and specificity of quantitative difference SPECT analysis in seizure localization.

Yohimbine alters regional cerebral blood flow in panic disorder

Significance of Nonuniform Attenuation Correction in Quantitative Brain SPECT Imaging

Opiate Dependence and Withdrawal: Preliminary Assessment Using Single Photon Emission Computerized Tomography (SPECT)