Is Perfusion MRI without Deconvolution Reliable for Mismatch Detection in Acute Stroke? Validation with 15O-Positron Emission Tomography

2018 ◽  
Vol 46 (1-2) ◽  
pp. 16-23 ◽  
Author(s):  
Johanna Reimer ◽  
Cornelia Montag ◽  
Alexander Schuster ◽  
Walter Moeller-Hartmann ◽  
Jan Sobesky ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
At Risk ◽  
Acute Stroke ◽  
Characteristic Curve ◽  
Area Under The Curve ◽  
Treatment Decisions ◽  
Emission Tomography ◽  
Time To Peak ◽  
Positron Emission ◽  
First Moment

Background: In acute stroke, the magnetic resonance (MR) imaging-based mismatch concept is used to select patients with tissue at risk of infarction for reperfusion therapies. There is however a controversy if non-deconvolved or deconvolved perfusion weighted (PW) parameter maps perform better in tissue at risk prediction and which parameters and thresholds should be used to guide treatment decisions. Methods: In a group of 22 acute stroke patients with consecutive MR and quantitative positron emission tomography (PET) imaging, non-deconvolved parameters were validated with the gold standard for penumbral-flow (PF) detection 15O-water PET. Performance of PW parameters was assessed by a receiver operating characteristic curve analysis to identify the accuracy of each PWI map to detect the ­upper PF threshold as defined by PET cerebral blood flow <20 mL/100 g/min. Results: Among normalized non-deconvolved parameters, PW-first moment without delay correction (FM without DC) > 3.6 s (area under the curve [AUC] = 0.89, interquartile range [IQR] 0.85–0.94), PW-maximum of the concentration curve (Cmax) < 0.66 (AUC = 0.92, IQR 0.84–0.96) and PW-time to peak (TTP) > 4.0 s (AUC = 0.92, IQR 0.87–0.94) perform significantly better than other non-deconvolved parameters to detect the PF threshold as defined by PET. Conclusions: Non-deconvolved parameters FM without DC, Cmax and TTP are an observer-independent alternative to established deconvolved parameters (e.g., Tmax) to guide treatment decisions in acute stroke.

scholarly journals Subacute cardiac rubidium-82 positron emission tomography (82Rb-PET) to assess myocardial area at risk, final infarct size, and myocardial salvage after STEMI

2016 ◽  
Vol 25 (3) ◽  
pp. 970-981 ◽  
Author(s):  
Adam Ali Ghotbi ◽  
Andreas Kjaer ◽  
Lars Nepper-Christensen ◽  
Kiril Aleksov Ahtarovski ◽  
Jacob Thomsen Lønborg ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
At Risk ◽  
Infarct Size ◽  
Emission Tomography ◽  
Myocardial Salvage ◽  
Area At Risk ◽  
Myocardial Area ◽  
Positron Emission ◽  
Final Infarct Size ◽  
Rubidium 82

scholarly journals Computed Tomography Assessment of Cerebral Perfusion Using a Distributed Parameter Tracer Kinetics Model: Validation with H2(15)O Positron Emission Tomography Measurements and Initial Clinical Experience in Patients with Acute Stroke

2007 ◽  
Vol 28 (2) ◽  
pp. 402-411 ◽  
Author(s):  
Sotirios Bisdas ◽  
Frank Donnerstag ◽  
Georg Berding ◽  
Thomas J Vogl ◽  
Choon Hua Thng ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Acute Stroke ◽  
Pet Imaging ◽  
Perfusion Ct ◽  
Emission Tomography ◽  
Minor Stroke ◽  
Distributed Parameter ◽  
Positron Emission

We describe a distributed parameter (DP) model for tracer kinetic analysis in brain and validate the derived perfusion values with positron emission tomography (PET) scans. The proposed model is applied on actual clinical cases of hemispheric stroke. Nine patients with experienced transient ischaemic attack or minor stroke and a stenosis of the internal carotid artery were referred for computed tomography (CT) and PET imaging. The applicability of the DP model in clinical practice was tested in seven patients with acute stroke who received a baseline perfusion CT study and a noncontrast follow-up CT study after 2.4 ± 1.8 days. The mean blood flow ( F) value for all patients with carotid stenosis in the pooled data (54 regions of interest (ROIs)) was 37.9 ± 11.2 mL/min per 100 g in perfusion CT and 35.6 ± 9.8 mL/min per 100 g in perfusion PET imaging [ r = 0.77 ( P = 0.00)]. Regression analysis of the pooled ROIs for every patient revealed significant correlation between F values in seven patients [ r = 0.50 to 0.79 ( r2-values ranged from 0.45 to 0.79), (0.01 ≤ P ≤ 0.05)]. Parametric maps that corresponded to all physiologic parameters were generated for every perfusion CT in the patients with acute stroke using the DP model. The ischaemic area was better delineated in F, intravascular blood volume and lag time ( tlag) maps. The correlation coefficient comparing the visually outlined regions of abnormality between the tlag parametric map and the follow-up CT scans was 0.81 ( P = 0.003). In conclusion, DP physiological model using more realistic pharmacokinetics is feasible in dynamic contrast-enhanced CT of the brain in patients with acute and chronic cerebrovascular disease.

scholarly journals Maps of Time to Maximum and Time to Peak for Mismatch Definition in Clinical Stroke Studies Validated With Positron Emission Tomography

Stroke ◽  
2010 ◽  
Vol 41 (12) ◽  
pp. 2817-2821 ◽  
Author(s):  
Olivier Zaro-Weber ◽  
Walter Moeller-Hartmann ◽  
Wolf-Dieter Heiss ◽  
Jan Sobesky
Keyword(s):  
Positron Emission Tomography ◽  
Emission Tomography ◽  
Time To Peak ◽  
Positron Emission

scholarly journals Permanent Cortical Damage Detected by Flumazenil Positron Emission Tomography in Acute Stroke

Stroke ◽  
1998 ◽  
Vol 29 (2) ◽  
pp. 454-461 ◽  
Author(s):  
Wolf-Dieter Heiss ◽  
Martin Grond ◽  
Alexander Thiel ◽  
Mehran Ghaemi ◽  
Jan Sobesky ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Acute Stroke ◽  
Emission Tomography ◽  
Cortical Damage ◽  
Positron Emission

scholarly journals Global and segmental absolute stress myocardial blood flow in prediction of cardiac events: [15O] water positron emission tomography study

2020 ◽  
Author(s):  
Esa Harjulahti ◽  
Teemu Maaniitty ◽  
Wail Nammas ◽  
Iida Stenström ◽  
Fausto Biancari ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Myocardial Blood Flow ◽  
Characteristic Curve ◽  
Obstructive Coronary Artery Disease ◽  
Cardiovascular Death ◽  
Emission Tomography ◽  
Cardiac Events ◽  
Positron Emission ◽  
Stress Myocardial Blood Flow

Abstract Purpose We evaluated the value of reduced global and segmental absolute stress myocardial blood flow (sMBF) quantified by [15O] water positron emission tomography (PET) for predicting cardiac events in patients with suspected obstructive coronary artery disease (CAD). Methods Global and segmental sMBF during adenosine stress were retrospectively quantified in 530 symptomatic patients who underwent [15O] water PET for evaluation of coronary stenosis detected by coronary computed tomography angiography. Results Cardiovascular death, myocardial infarction, or unstable angina occurred in 28 (5.3%) patients at a 4-year follow-up. Reduced global sMBF was associated with events (area under the receiver operating characteristic curve 0.622, 95% confidence interval (95% CI) 0.538–0.707, p = 0.006). Reduced global sMBF (< 2.2 ml/g/min) was found in 22.8%, preserved global sMBF despite segmentally reduced sMBF in 35.3%, and normal sMBF in 41.9% of patients. Compared with normal sMBF, reduced global sMBF was associated with the highest risk of events (adjusted hazard ratio (HR) 6.970, 95% CI 2.271–21.396, p = 0.001), whereas segmentally reduced sMBF combined with preserved global MBF predicted an intermediate risk (adjusted HR 3.251, 95% CI 1.030–10.257, p = 0.044). The addition of global or segmental reduction of sMBF to clinical risk factors improved risk prediction (net reclassification index 0.498, 95% CI 0.118–0.879, p = 0.010, and 0.583, 95% CI 0.203–0.963, p = 0.002, respectively). Conclusion In symptomatic patients evaluated for suspected obstructive CAD, reduced global sMBF by [15O] water PET identifies those at the highest risk of adverse cardiac events, whereas segmental reduction of sMBF with preserved global sMBF is associated with an intermediate event risk.

Scaled Subprofile Modeling and Convolutional Neural Networks for the Identification of Parkinson’s Disease in 3D Nuclear Imaging Data

2019 ◽  
Vol 29 (09) ◽  
pp. 1950010 ◽  
Author(s):  
Octavio Martinez Manzanera ◽  
Sanne K. Meles ◽  
Klaus L. Leenders ◽  
Remco J. Renken ◽  
Marco Pagani ◽  
...  
Keyword(s):  
Neural Networks ◽  
Parkinson’S Disease ◽  
Positron Emission Tomography ◽  
Parkinson's Disease ◽  
Convolutional Neural Networks ◽  
Fdg Pet ◽  
Characteristic Curve ◽  
Emission Tomography ◽  
Imaging Data ◽  
Positron Emission

Over the last years convolutional neural networks (CNNs) have shown remarkable results in different image classification tasks, including medical imaging. One area that has been less explored with CNNs is Positron Emission Tomography (PET). Fluorodeoxyglucose Positron Emission Tomography (FDG-PET) is a PET technique employed to obtain a representation of brain metabolic function. In this study we employed 3D CNNs in FDG-PET brain images with the purpose of discriminating patients diagnosed with Parkinson’s disease (PD) from controls. We employed Scaled Subprofile Modeling using Principal Component Analysis as a preprocessing step to focus on specific brain regions and limit the number of voxels that are used as input for the CNNs, thereby increasing the signal-to-noise ratio in our data. We performed hyperparameter optimization on three CNN architectures to estimate the classification accuracy of the networks on new data. The best performance that we obtained was [Formula: see text] and area under the receiver operating characteristic curve [Formula: see text] on the test set. We believe that, with larger datasets, PD patients could be reliably distinguished from controls by FDG-PET scans alone and that this technique could be applied to more clinically challenging tasks, like the differential diagnosis of neurological disorders with similar symptoms, such as PD, Progressive Supranuclear Palsy (PSP) and Multiple System Atrophy (MSA).

scholarly journals Tissue at Risk of Infarction Rescued by Early Reperfusion: A Positron Emission Tomography Study in Systemic Recombinant Tissue Plasminogen Activator Thrombolysis of Acute Stroke

1998 ◽  
Vol 18 (12) ◽  
pp. 1298-1307 ◽  
Author(s):  
Wolf-Dieter Heiss ◽  
Martin Grond ◽  
Alexander Thiel ◽  
Hans-Martin von Stockhausen ◽  
Jobst Rudolf ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Ischemic Stroke ◽  
Thrombolytic Therapy ◽  
Acute Stroke ◽  
Gray Matter ◽  
Recombinant Tissue Plasminogen Activator ◽  
Emission Tomography ◽  
Early Reperfusion ◽  
Positron Emission ◽  
Tissue Plasminogen

Thrombolytic therapy of acute ischemic stroke can be successful only as long as there is penumbral tissue perfused at rates between the thresholds of normal function and irreversible structural damage, respectively. To determine the proportion of tissue at risk of infarction, cerebral perfusion was studied in 12 patients with acute ischemic stroke who underwent treatment with systemic recombinant tissue plasminogen activator (0.9 mg/kg body weight according to National Institute of Neurological Disorders and Stroke protocol) within 3 hours of onset of symptoms, using [15O]-H2O positron emission tomography (PET) before or during, and repeatedly after thrombolysis. The size of the regions of critically hypoperfused gray matter were identified on the initial PET scans, and changes of perfusion in those areas were related to the clinical course (followed by the National Institutes of Health stroke scale) and to the volume of infarcted gray matter demarcated on magnetic resonance imaging 3 weeks after the stroke. Whereas the initial clinical score was unrelated to the size of the ischemic area, after 3 weeks there was a strong correlation between clinical deficit and volume size of infarcted gray matter (Spearman's rho, 0.96; P < 0.001). All patients with a severely hypoperfused (< 12 mL/100 g/min) gray matter region measuring less than 15 mL on first PET showed full morphologic and clinical recovery (n = 5), whereas those with ischemic areas larger than 20 mL developed infarction and experienced persistent neurologic deficits of varying degree. Infarct sizes, however, were smaller than expected from previous correlative PET and morphologic studies of patients with acute stroke: only 22.7% of the gray matter initially perfused at rates below the conventional threshold of critical ischemia became necrotic. Actually, the percentage of initially ischemic voxels that became reperfused at almost normal levels clearly predicted the degree of clinical improvement achieved within 3 weeks. These sequential blood flow PET studies demonstrate that critically hypoperfused tissue can be preserved by early reperfusion, perhaps related to thrombolytic therapy. The results correspond with experimental findings demonstrating the prevention of large infarcts by early reperfusion to misery perfused but viable tissue.

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