scholarly journals Image-Derived Input Function for Brain PET Studies: Many Challenges and Few Opportunities

2011 ◽  
Vol 31 (10) ◽  
pp. 1986-1998 ◽  
Author(s):  
Paolo Zanotti-Fregonara ◽  
Kewei Chen ◽  
Jeih-San Liow ◽  
Masahiro Fujita ◽  
Robert B Innis
Keyword(s):  
Invasive Procedure ◽  
Input Function ◽  
Emission Tomography ◽  
Alternative Methods ◽  
Less Invasive ◽  
Brain Pet ◽  
Positron Emission ◽  
Arterial Sampling ◽  
Challenging Technique ◽  
Methodological Problems

Quantitative positron emission tomography (PET) brain studies often require that the input function be measured, typically via arterial cannulation. Image-derived input function (IDIF) is an elegant and attractive noninvasive alternative to arterial sampling. However, IDIF is also a very challenging technique associated with several problems that must be overcome before it can be successfully implemented in clinical practice. As a result, IDIF is rarely used as a tool to reduce invasiveness in patients. The aim of the present review was to identify the methodological problems that hinder widespread use of IDIF in PET brain studies. We conclude that IDIF can be successfully implemented only with a minority of PET tracers. Even in those cases, it only rarely translates into a less-invasive procedure for the patient. Finally, we discuss some possible alternative methods for obtaining less-invasive input function.

scholarly journals Noninvasive Estimation of the Arterial Input Function in Positron Emission Tomography Imaging of Cerebral Blood Flow

2012 ◽  
Vol 33 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Yi Su ◽  
Ana M Arbelaez ◽  
Tammie LS Benzinger ◽  
Abraham Z Snyder ◽  
Andrei G Vlassenko ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Carotid Artery ◽  
Internal Carotid ◽  
Arterial Input Function ◽  
Input Function ◽  
Emission Tomography ◽  
Positron Emission ◽  
Arterial Sampling

Positron emission tomography (PET) with 15O-labeled water can provide reliable measurement of cerebral blood flow (CBF). Quantification of CBF requires knowledge of the arterial input function (AIF), which is usually provided by arterial blood sampling. However, arterial sampling is invasive. Moreover, the blood generally is sampled at the wrist, which does not perfectly represent the AIF of the brain, because of the effects of delay and dispersion. We developed and validated a new noninvasive method to obtain the AIF directly by PET imaging of the internal carotid artery in a region of interest (ROI) defined by coregistered high-resolution magnetic resonance angiography. An ROI centered at the petrous portion of the internal carotid artery was defined, and the AIF was estimated simultaneously with whole brain blood flow. The image-derived AIF (IDAIF) method was validated against conventional arterial sampling. The IDAIF generated highly reproducible CBF estimations, generally in good agreement with the conventional technique.

scholarly journals The Influence of Tissue Heterogeneity on Results of Fitting Nonlinear Model Equations to Regional Tracer Uptake Curves: With an Application to Compartmental Models Used in Positron Emission Tomography

1987 ◽  
Vol 7 (2) ◽  
pp. 214-229 ◽  
Author(s):  
K. Herholz ◽  
C. S. Patlak
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Glucose Metabolism ◽  
Capillary Permeability ◽  
Input Function ◽  
Tracer Uptake ◽  
Compartmental Models ◽  
Emission Tomography ◽  
Tissue Heterogeneity ◽  
Positron Emission

An analytical method based on Taylor expansions was developed to analyze errors caused by tissue heterogeneity in dynamic positron emission tomography (PET) measurements. Some general rules concerning the effect of parameter variances and covariances were derived. The method was further applied to various compartmental models currently used for measurement of blood flow, capillary permeability, glucose metabolism, and tracer binding. Blood flow and capillary permeability are shown to be generally underestimated in heterogenous tissue, the underestimation being more severe for slowly decaying, constant or increasing input functions rather than for bolus input, and increasing with measurement time. Typical errors caused by the heterogeneity due to insufficient separation between gray and white matter by a PET scanner with full width at half-maximum (FWHM)= 5 to 10 mm resolution range between–0.9 and–6% in dynamic CBF measurements with intravenous (i. v.) bolus injection of 15O-water or inhalation of 18F-fluoromethane and total measurement times of6 or 10 min, respectively. Binding or metabolic rates determined with tracers that are essentially trapped in tissue (e.g., FDG for measurement of cerebral glucose metabolism) are only slightly overestimated (0.5–3.0%) at typical measurement times and are essentially independent of the shape of the input function. The error increases considerably if tracer accumulation is very slow, however, or if short measurement times [<5/(k2 + k3)] are used. Some rate constants are also subject to larger errors.

scholarly journals Positron Emission Tomography/Magnetic Resonance Hybrid Scanner Imaging of Cerebral Blood Flow Using 15O-Water Positron Emission Tomography and Arterial Spin Labeling Magnetic Resonance Imaging in Newborn Piglets

2015 ◽  
Vol 35 (11) ◽  
pp. 1703-1710 ◽  
Author(s):  
Julie B Andersen ◽  
William S Henning ◽  
Ulrich Lindberg ◽  
Claes N Ladefoged ◽  
Liselotte Højgaard ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Arterial Spin Labeling ◽  
Input Function ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Newborn Piglets ◽  
Positron Emission

Abnormality in cerebral blood flow (CBF) distribution can lead to hypoxic–ischemic cerebral damage in newborn infants. The aim of the study was to investigate minimally invasive approaches to measure CBF by comparing simultaneous 15O-water positron emission tomography (PET) and single TI pulsed arterial spin labeling (ASL) magnetic resonance imaging (MR) on a hybrid PET/MR in seven newborn piglets. Positron emission tomography was performed with IV injections of 20 MBq and 100 MBq 15O-water to confirm CBF reliability at low activity. Cerebral blood flow was quantified using a one-tissue-compartment-model using two input functions: an arterial input function (AIF) or an image-derived input function (IDIF). The mean global CBF (95% CI) PET-AIF, PET-IDIF, and ASL at baseline were 27 (23; 32), 34 (31; 37), and 27 (22; 32) mL/100 g per minute, respectively. At acetazolamide stimulus, PET-AIF, PET-IDIF, and ASL were 64 (55; 74), 76 (70; 83) and 79 (67; 92) mL/100 g per minute, respectively. At baseline, differences between PET-AIF, PET-IDIF, and ASL were 22% ( P < 0.0001) and −0.7% ( P = 0.9). At acetazolamide, differences between PET-AIF, PET-IDIF, and ASL were 19% ( P = 0.001) and 24% ( P = 0.0003). In conclusion, PET-IDIF overestimated CBF. Injected activity of 20 MBq 15O-water had acceptable concordance with 100 MBq, without compromising image quality. Single TI ASL was questionable for regional CBF measurements. Global ASL CBF and PET CBF were congruent during baseline but not during hyperperfusion.

scholarly journals Arterial Input Function Derived from Pairwise Correlations Between PET-image Voxels

2013 ◽  
Vol 33 (7) ◽  
pp. 1058-1065 ◽  
Author(s):  
Martin Schain ◽  
Simon Benjaminsson ◽  
Katarina Varnäs ◽  
Anton Forsberg ◽  
Christer Halldin ◽  
...  
Keyword(s):  
Arterial Input Function ◽  
Pearson Correlation ◽  
Invasive Procedure ◽  
Compartmental Analysis ◽  
Input Function ◽  
Time Activity ◽  
Pairwise Correlation ◽  
Positron Emission ◽  
Using Data ◽  
Suitable Reference

A metabolite corrected arterial input function is a prerequisite for quantification of positron emission tomography (PET) data by compartmental analysis. This quantitative approach is also necessary for radioligands without suitable reference regions in brain. The measurement is laborious and requires cannulation of a peripheral artery, a procedure that can be associated with patient discomfort and potential adverse events. A non invasive procedure for obtaining the arterial input function is thus preferable. In this study, we present a novel method to obtain image-derived input functions (IDIFs). The method is based on calculation of the Pearson correlation coefficient between the time-activity curves of voxel pairs in the PET image to localize voxels displaying blood-like behavior. The method was evaluated using data obtained in human studies with the radioligands [ 11 C]flumazenil and [ 11 C]AZ10419369, and its performance was compared with three previously published methods. The distribution volumes ( VT) obtained using IDIFs were compared with those obtained using traditional arterial measurements. Overall, the agreement in VT was good (~3% difference) for input functions obtained using the pairwise correlation approach. This approach performed similarly or even better than the other methods, and could be considered in applied clinical studies. Applications to other radioligands are needed for further verification.

scholarly journals Repeatability of parametric methods for [18F]florbetapir imaging in Alzheimer’s disease and healthy controls: A test–retest study

2020 ◽  
pp. 0271678X2091540 ◽  
Author(s):  
Sander CJ Verfaillie ◽  
Sandeep SV Golla ◽  
Tessa Timmers ◽  
Hayel Tuncel ◽  
Chris WJ van der Weijden ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Standardized Uptake Value ◽  
Emission Tomography ◽  
Parametric Methods ◽  
Excellent Performance ◽  
Reference Tissue ◽  
Positron Emission ◽  
Arterial Sampling ◽  
Pet Scans

Accumulation of amyloid beta (Aβ) is one of the pathological hallmarks of Alzheimer’s disease (AD), which can be visualized using [18F]florbetapir positron emission tomography (PET). The aim of this study was to evaluate various parametric methods and to assess their test-retest (TRT) reliability. Two 90 min dynamic [18F]florbetapir PET scans, including arterial sampling, were acquired ( n = 8 AD patient, n = 8 controls). The following parametric methods were used; (reference:cerebellum); Logan and spectral analysis (SA), receptor parametric mapping (RPM), simplified reference tissue model2 (SRTM2), reference Logan (rLogan) and standardized uptake value ratios (SUVr(50–70)). BPND+1, DVR, VT and SUVr were compared with corresponding estimates (VT or DVR) from the plasma input reversible two tissue compartmental (2T4k_VB) model with corresponding TRT values for 90-scan duration. RPM ( r2 = 0.92; slope = 0.91), Logan ( r2 = 0.95; slope = 0.84) and rLogan ( r2 = 0.94; slope = 0.88), and SRTM2 ( r2 = 0.91; slope = 0.83), SA ( r2 = 0.91; slope = 0.88), SUVr ( r2 = 0.84; slope = 1.16) correlated well with their 2T4k_VB counterparts. RPM (controls: 1%, AD: 3%), rLogan (controls: 1%, AD: 3%) and SUVr(50–70) (controls: 3%, AD: 8%) showed an excellent TRT reliability. In conclusion, most parametric methods showed excellent performance for [18F]florbetapir, but RPM and rLogan seem the methods of choice, combining the highest accuracy and best TRT reliability.

scholarly journals In vivo evidence for dysregulation of mGluR5 as a biomarker of suicidal ideation

2019 ◽  
Vol 116 (23) ◽  
pp. 11490-11495 ◽  
Author(s):  
Margaret T. Davis ◽  
Ansel Hillmer ◽  
Sophie E. Holmes ◽  
Robert H. Pietrzak ◽  
Nicole DellaGioia ◽  
...  
Keyword(s):  
Suicidal Ideation ◽  
Suicide Risk ◽  
Potential Role ◽  
Input Function ◽  
Brain Regions ◽  
Volume Of Distribution ◽  
Regions Of Interest ◽  
Emission Tomography ◽  
Positron Emission

Recent evidence implicates dysregulation of metabotropic glutamatergic receptor 5 (mGluR5) in pathophysiology of PTSD and suicidality. Using positron emission tomography and [18F]FPEB, we quantified mGluR5 availability in vivo in individuals with PTSD (n = 29) and MDD (n = 29) as a function of suicidal ideation (SI) to compare with that of healthy comparison controls (HC; n = 29). Volume of distribution was computed using a venous input function in the five key frontal and limbic brain regions. We observed significantly higher mGluR5 availability in PTSD compared with HC individuals in all regions of interest (P’s = 0.001–0.01) and compared with MDD individuals in three regions (P’s = 0.007). mGluR5 availability was not significantly different between MDD and HC individuals (P = 0.17). Importantly, we observed an up-regulation in mGluR5 availability in the PTSD-SI group (P’s = 0.001–0.007) compared with PTSD individuals without SI. Findings point to the potential role for mGluR5 as a target for intervention and, potentially, suicide risk management in PTSD.

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