Gray Matter Segmentation and Delineation from Positron Emission Tomography (PET) Image

2019 ◽  
pp. 359-372
Author(s):  
Abhishek Bal ◽  
Minakshi Banerjee ◽  
Punit Sharma ◽  
Mausumi Maitra
Keyword(s):  
Positron Emission Tomography ◽  
Gray Matter ◽  
Emission Tomography ◽  
Positron Emission

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.

scholarly journals Arterial Spin Labeling Perfusion MRI at Multiple Delay Times: A Correlative Study with H215O Positron Emission Tomography in Patients with Symptomatic Carotid Artery Occlusion

2009 ◽  
Vol 30 (1) ◽  
pp. 222-229 ◽  
Author(s):  
Reinoud PH Bokkers ◽  
Jochem P Bremmer ◽  
Bart NM van Berckel ◽  
Adriaan A Lammertsma ◽  
Jeroen Hendrikse ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Carotid Artery ◽  
Cerebral Artery ◽  
Gray Matter ◽  
Arterial Spin Labeling ◽  
Spin Labeling ◽  
Emission Tomography ◽  
Perfusion Magnetic Resonance Imaging ◽  
Positron Emission

Arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) with image acquisition at multiple inversion times is a noninvasive ASL technique able to compensate for spatial heterogeneities in transit times caused by collateral blood flow in patients with severe stenosis of the cerebropetal blood vessels. Our aim was to compare ASL-MRI and H215O positron emission tomography (PET), the gold standard for cerebral blood flow (CBF) assessment, in patients with a symptomatic internal carotid artery (ICA) occlusion. Fourteen patients (63±14 years) with a symptomatic ICA occlusion underwent both ASL-MRI and H215O PET. The ASL-MRI was performed using a pulsed STAR labeling technique at multiple inversion times within 7 days of the PET. The CBF was measured in the gray-matter of the anterior, middle and posterior cerebral artery, and white-matter. Both PET and ASL-MRI showed a significantly decreased CBF in the gray-matter of the middle cerebral artery in the hemisphere ipsilateral to the ICA occlusion. The average gray-matter CBF measured with ASL-MRI (71.8±4.3 mL/min/100 g) was higher ( P<0.01) than measured with H215O PET (43.1±1.0 mL/min/100 g). In conclusion, ASL-MRI at multiple TIs is capable of depicting areas of regions with low CBF in patients with an occlusion of the ICA, although a systematic overestimation of CBF relative to H215O PET was noted.

scholarly journals Measurement of Radiotracer Concentration in Brain Gray Matter Using Positron Emission Tomography: MRI-Based Correction for Partial Volume Effects

1992 ◽  
Vol 12 (4) ◽  
pp. 571-583 ◽  
Author(s):  
Hans W. Müller-Gärtner ◽  
Jonathan M. Links ◽  
Jerry L. Prince ◽  
R. Nick Bryan ◽  
Elliot McVeigh ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Computer Simulations ◽  
Gray Matter ◽  
Emission Tomography ◽  
Tracer Concentration ◽  
Partial Volume ◽  
Partial Volume Effects ◽  
Positron Emission ◽  
Volume Effects

Accuracy in in vivo quantitation of brain function with positron emission tomography (PET) has often been limited by partial volume effects. This limitation becomes prominent in studies of aging and degenerative brain diseases where partial volume effects vary with different degrees of atrophy. The present study describes how the actual gray matter (GM) tracer concentration can be estimated using an algorithm that relates the regional fraction of GM to partial volume effects. The regional fraction of GM was determined by magnetic resonance imaging (MRI). The procedure is designated as GM PET. In computer simulations and phantom studies, the GM PET algorithm permitted a 100% recovery of the actual tracer concentration in neocortical GM and hippocampus, irrespective of the GM volume. GM PET was applied in a test case of temporal lobe epilepsy revealing an increase in radiotracer activity in GM that was undetected in the PET image before correction for partial volume effects. In computer simulations, errors in the segmentation of GM and errors in registration of PET and MRI images resulted in less than 15% inaccuracy in the GM PET image. In conclusion, GM PET permits accurate determination of the actual radiotracer concentration in human brain GM in vivo. The method differentiates whether a change in the apparent radiotracer concentration reflects solely an alteration in GM volume or rather a change in radiotracer concentration per unit volume of GM.

The neuronal component of gray matter damage in multiple sclerosis: A [11C]flumazenil positron emission tomography study

2015 ◽  
Vol 78 (4) ◽  
pp. 554-567 ◽  
Author(s):  
Léorah Freeman ◽  
Daniel Garcia-Lorenzo ◽  
Laure Bottin ◽  
Claire Leroy ◽  
Céline Louapre ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Positron Emission Tomography ◽  
Gray Matter ◽  
Emission Tomography ◽  
Positron Emission Tomography Study ◽  
Positron Emission

Combined use of 18F-fluorodeoxyglucose and 11C-methionine in 45 positron emission tomography—guided stereotactic brain biopsies

2004 ◽  
Vol 101 (3) ◽  
pp. 476-483 ◽  
Author(s):  
Benoit Pirotte ◽  
Serge Goldman ◽  
Nicolas Massager ◽  
Philippe David ◽  
David Wikler ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Gray Matter ◽  
Stereotactic Biopsy ◽  
Emission Tomography ◽  
Content Type ◽  
Fdg Uptake ◽  
Positron Emission ◽  
Target Definition ◽  
Met Pet ◽  
Fine Print

Object. The aim of this study was to compare the contribution of the tracers 11C-methionine (Met) and 18F-fluorodeoxyglucose (FDG) in positron emission tomography (PET)—guided stereotactic brain biopsy. Methods. Forty-five patients underwent combined Met-PET and FDG-PET studies associated with computerized tomography (CT)— or magnetic resonance (MR)—guided stereotactic biopsy. Each patient presented with a lesion that was in proximity to the cortical or subcortical gray matter. The Met-PET and FDG-PET scans were analyzed to determine which tracer offers the best information to guide at least one stereotactic biopsy trajectory. Histologically based diagnoses were rendered in all patients (39 tumors, six nontumorous lesions) and biopsies were performed in all tumors with the aid of PET guidance. When tumor FDG uptake was higher than that in the gray matter (18 tumors), FDG was used for target definition. When FDG uptake was absent or equivalent to that in the gray matter (21 tumors), Met was used for target definition. Parallel review of all histological and imaging data showed that all tumors had an area of abnormal Met uptake and 33 had abnormal FDG uptake. All six nontumorous lesions had no Met uptake and biopsies were performed using CT or MR guidance only. All tumor trajectories had an area of abnormal Met uptake; all nondiagnostic trajectories in tumors had no abnormal Met uptake. Conclusions. When FDG shows limitations in target selection, Met is a good alternative because of its high specificity in tumors. Moreover, in the context of a single-tracer procedure and regardless of FDG uptake, Met is a better choice for PET guidance in neurosurgical procedures.

scholarly journals Absolute Quantification of Cerebral Blood Flow with Magnetic Resonance, Reproducibility of the Method, and Comparison with H215O Positron Emission Tomography

2002 ◽  
Vol 22 (9) ◽  
pp. 1149-1156 ◽  
Author(s):  
Timothy J. Carroll ◽  
Vincenzo Teneggi ◽  
Mathieu Jobin ◽  
Lisa Squassante ◽  
Valerie Treyer ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
White Matter ◽  
Gray Matter ◽  
Cerebral Perfusion ◽  
Emission Tomography ◽  
Mr Perfusion ◽  
Altman Analysis ◽  
Bland Altman Analysis ◽  
Positron Emission ◽  
The Difference

While H215O positron emission tomography (PET) is still the gold standard in the quantitative assessment of cerebral perfusion (rCBF), its technical challenge, limited availability, and radiation exposure are disadvantages of the method. Recent work demonstrated the feasibility of magnetic resonance (MR) for quantitative cerebral perfusion imaging. There remain open questions, however, especially regarding reproducibility. The main purpose of this study was to assess the accuracy and reproducibility of MR-derived flow values to those derived from H215O PET. Positron emission tomography and MR perfusion imaging was performed in 20 healthy male volunteers, who were chronic smokers, on day 1 and day 3 of a 4-day hospitalization. Subjects were randomly assigned to one of two groups, each with 10 subjects. One group was allowed to smoke as usual during the hospitalization, while the other group stopped smoking from day 2. Positron emission tomography and MR images were coregistered and rCBF was determined in two regions of interest, defined over gray matter (gm) and white matter (wm), yielding rCBFPETgm, rCBFMRgm, rCBFPETwm, and rCBFMRwm. Bland-Altman analysis was used to investigate reproducibility by assessing the difference rCBFday3 - rCBFday1 in eight continual-smoker volunteers. The analysis showed a good reproducibility for PET, but not for MR. Mean ± SD of the difference rCBFday3 - rCBFday1 in gray matter was 6.35 ± 21.06 and 0.49 ± 5.27 mL · min−1 · 100 g−1 for MR and PET, respectively; the corresponding values in white matter were 2.60 ± 15.64 and −1.14 ± 4.16 mL · min−1 · 100 g−1. The Bland-Altman analysis was also used to assess MRI and PET agreement comparing rCBF measured on day 1. The analysis demonstrated a reasonably good agreement of MR and PET in white matter (rCBFPETwm - rCBFMRwm; −0.09 ± 7.23 mL · min−1 · 100 g−1), while in gray matter a reasonable agreement was only achieved after removing vascular artifacts in the MR perfusion maps (rCBFPETgm - rCBFMRgm; −11.73 ± 14.52 mL · min−1 · 100 g−1). In line with prior work, these results demonstrate that reproducibility was overall considerably better for PET than for MR. Until reproducibility is improved and vascular artifacts are efficiently removed, MR is not suitable for reliable quantitative perfusion measurements.

scholarly journals Quantitative positron emission tomography reveals regional differences in aerobic glycolysis within the human brain

2018 ◽  
Vol 39 (10) ◽  
pp. 2096-2102 ◽  
Author(s):  
Tyler Blazey ◽  
Abraham Z Snyder ◽  
Yi Su ◽  
Manu S Goyal ◽  
John J Lee ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Oxidative Phosphorylation ◽  
Human Brain ◽  
Gray Matter ◽  
Regional Differences ◽  
Aerobic Glycolysis ◽  
Oxygen Metabolism ◽  
Emission Tomography ◽  
Published Data ◽  
Positron Emission

Glucose and oxygen metabolism are tightly coupled in the human brain, with the preponderance of the brain’s glucose supply used to generate ATP via oxidative phosphorylation. A fraction of glucose is consumed outside of oxidative phosphorylation despite the presence of sufficient oxygen to do so. We refer to this process as aerobic glycolysis. A recent positron emission tomography study reported that aerobic glycolysis is uniform within gray matter. Here, we analyze the same data and demonstrate robust regional differences in aerobic glycolysis within gray matter, a finding consistent with previously published data.

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