scholarly journals Imaging lung perfusion

2012 ◽  
Vol 113 (2) ◽  
pp. 328-339 ◽  
Author(s):  
Susan R. Hopkins ◽  
Mark O. Wielpütz ◽  
Hans-Ulrich Kauczor

From the first measurements of the distribution of pulmonary blood flow using radioactive tracers by West and colleagues ( J Clin Invest 40: 1–12, 1961) allowing gravitational differences in pulmonary blood flow to be described, the imaging of pulmonary blood flow has made considerable progress. The researcher employing modern imaging techniques now has the choice of several techniques, including magnetic resonance imaging (MRI), computerized tomography (CT), positron emission tomography (PET), and single photon emission computed tomography (SPECT). These techniques differ in several important ways: the resolution of the measurement, the type of contrast or tag used to image flow, and the amount of ionizing radiation associated with each measurement. In addition, the techniques vary in what is actually measured, whether it is capillary perfusion such as with PET and SPECT, or larger vessel information in addition to capillary perfusion such as with MRI and CT. Combined, these issues affect quantification and interpretation of data as well as the type of experiments possible using different techniques. The goal of this review is to give an overview of the techniques most commonly in use for physiological experiments along with the issues unique to each technique.

2000 ◽  
Vol 6 (2) ◽  
pp. 109-119 ◽  
Author(s):  
John O'Brien ◽  
Bob Barber

Neuroimaging is traditionally divided into structural and functional imaging. Structural imaging looks at brain structure or anatomy and includes computed tomography (CT) and magnetic resonance imaging (MRI). Functional techniques seek to examine the physiological functioning of the brain, either at rest or during activation, and include single photon emission computed tomography (SPECT), positron emission tomography (PET), MRI spectroscopy, functional MRI (fMRI) and encephalographic brain mapping. Although fMRI, MRI spectroscopy and brain mapping are likely to have clinical applications in the near future, the main imaging modalities of current clinical relevance to psychiatrists are CT, MRI and SPECT, which will be the focus of this article.


2006 ◽  
Vol 16 (06) ◽  
pp. 1671-1687 ◽  
Author(s):  
A. S. FOKAS ◽  
V. MARINAKIS

The imaging techniques of magnetoencephalography (MEG), computed tomography (CT), positron emission tomography (PET) and single photon emission computed tomography (SPECT) are reviewed, and the analytical solutions of the relevant inverse problems are presented. The numerical implementation of the exact formulas yield accurate reconstructions for both realistic phantoms as well as real data.


2011 ◽  
Vol 6 (4) ◽  
pp. 257
Author(s):  
Doris D Wang ◽  
Carlos Santos-Sanchez ◽  
Paul A Garcia ◽  
Edward F Chang ◽  
◽  
...  

Localising the onset of seizures to guide epilepsy surgery can be notoriously difficult. Modern neuroimaging has revolutionised the field by improving the diagnosis and treatment of epilepsy. In order to ameliorate seizures without causing new neurological morbidity, many imaging tools have been developed to guide safe and effective resective surgery. In this article, we discuss recent advances in structural imaging using ultrahigh-field magnetic resonance imaging, metabolic functional imaging techniques of positron emission tomography and single photon emission computed tomography and electrophysiological imaging using magnetoencephalography. Our goal is to provide an overview of these state-of-the-art imaging modalities, their role in guiding surgery, and how they are incorporated into the pre-surgical evaluation of epilepsy.


2020 ◽  
Vol 21 (23) ◽  
pp. 9190
Author(s):  
Olga Krasnovskaya ◽  
Daniil Spector ◽  
Alexander Zlobin ◽  
Kirill Pavlov ◽  
Peter Gorelkin ◽  
...  

One of the hallmarks of Alzheimer’s disease (AD) is the deposition of amyloid plaques in the brain parenchyma, which occurs 7–15 years before the onset of cognitive symptoms of the pathology. Timely diagnostics of amyloid formations allows identifying AD at an early stage and initiating inhibitor therapy, delaying the progression of the disease. However, clinically used radiopharmaceuticals based on 11C and 18F are synchrotron-dependent and short-lived. The design of new metal-containing radiopharmaceuticals for AD visualization is of interest. The development of coordination compounds capable of effectively crossing the blood-brain barrier (BBB) requires careful selection of a ligand moiety, a metal chelating scaffold, and a metal cation, defining the method of supposed Aβ visualization. In this review, we have summarized metal-containing drugs for positron emission tomography (PET), magnetic resonance imaging (MRI), and single-photon emission computed tomography (SPECT) imaging of Alzheimer’s disease. The obtained data allow assessing the structure-ability to cross the BBB ratio.


2000 ◽  
Vol 10 (1) ◽  
pp. 55-68 ◽  
Author(s):  
H. Förstl ◽  
F. Hentschel

IntroductionThis is a review of recent and clinically relevant work on neuroimaging and its contribution to the diagnosis of neurodegenerative or other neurological and psychiatric diseases in older patients. Earlier research has been summarized in our previous review. We include publications on cranial computed tomography (CT) and magnetic resonance imaging (MRI), on single photon emission computed tomography (SPECT) and positron emission tomography (PET), electroencephalo-graphy (EEG), and on other methods.


1988 ◽  
Vol 8 (1_suppl) ◽  
pp. S90-S94 ◽  
Author(s):  
K.-J. Langen ◽  
H. Herzog ◽  
T. Kuwert ◽  
N. Roosen ◽  
E. Rota ◽  
...  

In 10 patients with malignant gliomas, the intracerebral distribution of [99mTc]–hexamethylpropyleneamine oxime ([99mTc]–HM-PAO) was studied with single photon emission computed tomography (SPECT) in comparison with C15O2 steady-state inhalation technique to measure cerebral blood flow using positron emission tomography (PET). In all instances, the cerebral [99mTc]–HM-PAO distribution was comparable with the regional pattern of cerebral blood flow (rCBF) observed with PET. This was confirmed by a significant correlation of tumor to cortex and tumor to white matter ratios between these two experimental methods. However, the contrast between high and low activity regions in the SPECT scans was significantly less than that in the PET scans. Contrast enhancement of the SPECT scans was accomplished using a correction formula proposed by Lassen.


2012 ◽  
Vol 67 (9) ◽  
pp. 13-18 ◽  
Author(s):  
A. M. Granov ◽  
L. A. Tyutin ◽  
A. A. Stanzhevskii

Analysis of use of nuclear medicine imaging (positron emission tomography and single photon emission computed tomography) in diagnosis, differential diagnosis and evaluation of treatment efficacy of central nervous system diseases is presented in this review. The possibility of radionuclide imaging techniques in different variants of dementia, Parkinson's disease, brain tumors is demonstrated on the basis of personal authors experience and recent literature data. Results of PET application in evaluating of the effecacy of stereotactic interventions in patients with anxiety obsessive disorders are also described in the review. 


Author(s):  
Allison C. Nugent ◽  
Maura L. Furey

Neuroscience research has clearly demonstrated neurological correlates of psychological disorders. We believe that neuroscience, particularly neuroimaging, has great potential to increase our understanding of these disorders, leading to more effective treatments, prevention, and perhaps even cure. Nevertheless, the popular media is replete with misinformation and exaggerated claims. The present chapter is intended to give the reader the necessary knowledge to critically evaluate neuroimaging studies of psychological disorders. We provide an overview of all the major neuroimaging techniques, example studies relevant to psychological disorders (with a particular emphasis on depression), particular pitfalls and caveats associated with each technique, and the promise of each technique. We first cover the nuclear imaging techniques, single photon emission computed tomography (SPECT) and positron emission tomography (PET). We then explore several magnetic resonance imaging (MRI) techniques, both structural and functional. Finally, we give an overview of the electrophysiological techniques, electroencephalography (EEG) and magnetoencephalography (MEG). Each of these techniques has particular strengths, and particular weaknesses. At this point, none of these tools are diagnostic, but each one provides a unique window into psychological disorders. When applied in a methodologically rigorous and statistically rigorous manner, neuroimaging has great promise for achieving greater understanding of psychological disorders, and relieving the great burdens they cause.


2014 ◽  
Vol 2014 ◽  
pp. 1-24 ◽  
Author(s):  
Oyebola O. Sogbein ◽  
Matthieu Pelletier-Galarneau ◽  
Thomas H. Schindler ◽  
Lihui Wei ◽  
R. Glenn Wells ◽  
...  

Nuclear cardiology has experienced exponential growth within the past four decades with converging capacity to diagnose and influence management of a variety of cardiovascular diseases. Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with technetium-99m radiotracers or thallium-201 has dominated the field; however new hardware and software designs that optimize image quality with reduced radiation exposure are fuelling a resurgence of interest at the preclinical and clinical levels to expand beyond MPI. Other imaging modalities including positron emission tomography (PET) and magnetic resonance imaging (MRI) continue to emerge as powerful players with an expanded capacity to diagnose a variety of cardiac conditions. At the forefront of this resurgence is the development of novel target vectors based on an enhanced understanding of the underlying pathophysiological process in the subcellular domain. Molecular imaging with novel radiopharmaceuticals engineered to target a specific subcellular process has the capacity to improve diagnostic accuracy and deliver enhanced prognostic information to alter management. This paper, while not comprehensive, will review the recent advancements in radiotracer development for SPECT and PET MPI, autonomic dysfunction, apoptosis, atherosclerotic plaques, metabolism, and viability. The relevant radiochemistry and preclinical and clinical development in addition to molecular imaging with emerging modalities such as cardiac MRI and PET-MR will be discussed.


2016 ◽  
Author(s):  
Μαρία Γεωργίου

Η μοριακή απεικόνιση ορίζεται ως η in-vivo μη επεμβατική απεικόνιση, αξιολόγηση και ποσοτικοποίηση των φυσιολογικών και παθολογικών διεργασιών ενός ζωντανού οργανισμού σε πραγματικό χρόνο. Οι ιχνηθέτες που έχουν αναπτυχθεί τα τελευταία χρόνια για την μοριακή απεικόνιση είναι κατάλληλα σχεδιασμένοι ώστε να στοχεύουν σε συγκεκριμένα μόρια που εκφράζουν τις διεργασίες του οργανισμού σε λειτουργικό και μεταβολικό επίπεδο. Τα δεδομένα που παράγονται από τις μελέτες μοριακής απεικόνισης βοηθούν στην κατανόηση βιολογικών φαινομένων, στην αναγνώριση παθολογικών περιοχών και στην ανάδειξη των παθοφυσιολογικών μηχανισμών των νόσων. Επομένως, η μοριακή απεικόνιση συνεισφέρει σημαντικά όχι μόνο στην πρόγνωση αλλά και στη διάγνωση, στην παρακολούθηση των θεραπευτικών σχημάτων και στην ανακάλυψη νέων φαρμάκων. Σήμερα, υπάρχουν πέντε κύριες μέθοδοι μοριακής απεικόνισης: α) η απεικόνιση μαγνητικού συντονισμού (Magnetic Resonance Imaging –MRI), β) η απεικόνιση αξονικής τομογραφίας (Computed Tomography – CT), γ) η υπερηχοτομογραφία (Ultrasound – US), δ) η οπτική απεικόνιση (Optical Imaging) και ε) οι ραδιοϊσοτοπικές απεικονιστικές μέθοδοι υπολογιστικής τομογραφίας μονοφωτονιακής εκπομπής (Single Photon Emission Computed Tomography - SPECT) και τομογραφίας εκπομπής ποζιτρονίων (Positron Emission Tomography - ΡΕΤ). Αναλόγως της βιοχημικής φυσιολογικής ή παθολογικής διεργασίας του οργανισμού που θέλουμε να απεικονίσουμε, επιλέγεται η κατάλληλη απεικονιστική μέθοδος με κατάλληλο ιχνηθέτη, αν και ο συνδυασμός περισσότερων μεθοδολογιών παρέχει συμπληρωματική πληροφορία. Σημαντική θέση στην μοριακή απεικόνιση κατέχουν οι ραδιοϊσοτοπικές μέθοδοι καθώς μαζί με τις οπτικές μεθόδους αποτελούν την αφετηρία αυτής. Τα εμπορικά διαθέσιμα κλινικά SPECT και ΡΕΤ συστήματα όπως και τα υβριδικά συστήματα SPECT/CT και ΡΕΤ/CT ή ΡΕΤ/MRI χρησιμοποιούνται ευρέως στην ογκολογία για τη διάγνωση, σταδιοποίηση και παρακολούθηση της θεραπείας της νόσου, αλλά και για τη διάγνωση άλλων ασθενειών όπως νευρολογικές και καρδιολογικές παθήσεις. Με την εξέλιξη της τεχνολογίας, τα απεικονιστικά συστήματα βελτιώνονται συνεχώς και η τάση που επικρατεί τη τελευταία δεκαετία είναι η ανάπτυξη εξειδικευμένων απεικονιστικών συστημάτων συγκεκριμένων οργάνων, πχ εγκέφαλος, μαστός, καρδιά, προστάτης, τα οποία προσφέρουν πολύ υψηλές επιδόσεις συγκριτικά με τα αντίστοιχα κλινικά που είναι σχεδιασμένα για ένα μεγάλο εύρος εφαρμογών. Τα νέα εξειδικευμένα συστήματα SPECT και ΡΕΤ βασίζονται στους φωτοπολλαπλασιαστές νέας γενιάς (φωτοπολλαπλασιαστές ευαισθησίας θέσης), οι οποίοι έχουν μικρές διαστάσεις, υψηλή χωρική διακριτική ικανότητα και έτσι επιτρέπουν την κατασκευή ανιχνευτών που να απεικονίζουν μόνο το υπο-εξέταση όργανο μειώνοντας την επίδραση της ακτινοβολίας των υπόλοιπων οργάνων. Με αυτό τον τρόπο είναι δυνατή η απεικόνιση δομών σε επίπεδο μερικών χιλιοστών (1-2 mm) σε αντίθεση με τα κλινικά συστήματα των οποίων η χωρική διακριτική ικανότητα είναι της τάξης των 5-8 mm. Εκτός από την κλινική πράξη, τα εξειδικευμένα SPECT και ΡΕΤ συστήματα βρίσκουν ιδιαίτερη εφαρμογή στην απεικόνιση πειραματόζωων, ένα πεδίο που συνήθως αποτελεί το βασικό χώρο καινοτομίας πριν την κλινική μεταφορά.Η παρούσα διδακτορική διατριβή στοχεύει στη σχεδίαση, βελτιστοποίηση και κατασκευή εξειδικευμένων σπινθηρογραφικών συστημάτων για την απεικόνιση πειραματόζωων, τη σπινθηρομαστογραφία και την απεικόνιση του λεμφαδένα. Συγκεκριμένα, αρχικά μελετήθηκε ένα πρότυπο σύστημα σπινθηρομαστογραφίας και ακολούθως κατασκευάστηκαν δύο ολοκληρωμένα συστήματα, το πρώτο για την ολόσωμη απεικόνιση μυών και το δεύτερο για την απεικόνιση των λεμφαδένων με υψηλή ευαισθησία.


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