Name: Determining Glucose Metabolism Kinetics Using 18F-FDG Micro-PET/CT (Video) | JoVE Journal
Uploaded: 2017-05-02T14:30:00.000+00:00
Duration: 7 min 7 s
Description: Learn kinetic modeling of glucose metabolism using 18F-FDG micro-PET/CT imaging in mice. This protocol enables real-time quantification of tissue glucose uptake for diabetes and metabolic research.

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5 minutes

This work was supported by a National Imaging Facility Subsidised Access Grant to BJC, a National Health and Medical Research Council of Australia program grant (482800) to KAR and PJB. The authors would like to thank Andrew Arthur, Hasar Hazme and Marie-Claude Gregoire for support in developing this method.

All procedures described in this study were approved by the Sydney Local Health District and University of Sydney Animal Ethics Committees and followed the NIH Guide for the care and use of laboratory animals, Eighth edition (2011).
1. Animal Preparation
NOTE: In this protocol male db/db mice (BKS.Cg-Dock7m +/+ Leprdb/J) were maintained in group housing with ad libitum access to chow and water until 6 weeks of age. At the time of imaging, mice weighed ~ 30 g. All mice used in this protocol had fasting blood glucose levels between 10 and 14 mmol/L.
<ol>
	<li>If required, fast the mice. In the present example, fast the mice for 5 h prior to the experimental procedure.</li>
	<li>Treat mice with the desired agent (e.g. drug, protein, peptide) before the commencement of imaging. In this example, administer a subcutaneous injection of insulin (3 U/kg human insulin) or equivalent volume PBS 30 min prior to the start of imaging.</li>
</ol>
2. Set up Workflow
NOTE: This protocol was implemented on a PET/CT scanner. Acquire PET data first, followed by acquisition of CT data.
<ol>
	<li>PET settings:
	<ol>
		<li>Select isotope as 18F, set scan duration to 3,600 s, and upper and lower level energy discrimination to 350 keV - 650 keV (default) with a coincidence timing window of 3.432 ns (default). Histogram list-mode data into 16 frames (6 &#215; 10 s, 4 &#215; 60 s, 1 &#215; 300 s, 5 &#215; 600 s) for the period 0 - 60 min after tracer injection. Reconstruct emission sinograms using 2D-FBP with a zoom 1.5. 
		NOTE: The reconstructed images consisted of 16 dynamic frames, each with 128 &#215; 128 &#215; 159 voxels and a voxel size of 0.52 &#215; 0.52 &#215; 0.796 mm3.</li>
	</ol>
	</li>
	<li>CT settings:
	<ol>
		<li>For a whole body CT scan, set the current at 500 A, voltage at 50 kV, exposure time 500 ms and 200 projections over a 360 rotation. Set the detector field of view (FoV) to 30722048, number of bed positions to 3 (to cover full PET FoV range), overlap between bed positions = 30.234713% and detector binning to 4. 
		NOTE: CT reconstruction was performed using cone beam tomography image reconstruction software with HU calibration, bilinear interpolation and Shepp-Logan filter.</li>
	</ol>
	</li>
	<li>18 F-FDG:
	<ol>
		<li>Order sufficient 18F-FDG (for example 450 MBq in 0.5 mL) from a local provider to arrive ~ 30 min before the first injection. Aliquot and dilute the 18F-FDG so that animals receive ~ 10 MBq of 18F-FDG in a final volume of 0.1 mL.</li>
	</ol>
	</li>
</ol>
3. Imaging Protocol
<ol>
	<li>Wipe down induction chamber and imaging bed with 80% (v/v) ethanol to maintain aseptic conditions. Place the mouse in an induction chamber and anesthetize with 5% isoflurane in oxygen.</li>
	<li>Place the mouse onto an imaging bed fitted with an electric heating pad to maintain body temperature and a precision vaporizer nose cone to deliver isoflurane (maintenance, 1.5 - 2%) at a flow rate of 1 L/min. Apply ophthalmic ointment onto eyes to prevent dryness whilst under anesthesia.</li>
	<li>Position the mouse in a prone position on a sensor pad to monitor breathing and ensure an adequate plane of anesthesia is maintained.</li>
	<li>Warm the tail using a heat pack for 1 - 2 min to dilate the lateral tail vein. Catheterize the lateral tail vein by inserting a 30-gauge needle into the lateral tail vein. Secure the needle in place with surgical glue and secure the catheter.</li>
	<li>Load imaging bed into the scanner and move the bed through the machine so that the catheter can be accessed from the rear of the machine.</li>
	<li>Attach the catheter to the 18F-FDG syringe in a syringe driver. Calculate the exact 18F-FDG dose (10 MBq) based on activity in syringe before injection and the volume to be administered (&#60; 100 &#956;L, injected over 10 s).</li>
	<li>To minimize the impact of anesthesia on variability of glucose uptake, ensure a constant time between induction of anesthesia and injection of 18F-FDG (for example, 30 min).</li>
	<li>Commence the PET scan immediately before injection of 18F-FDG. After finishing the PET scan (3,600 s), perform a CT scan (~ 10 min) to allow for co-registration of radiotracer uptake with tissues.</li>
	<li>Move the imaging bed to the starting position, remove the animal from the bed.</li>
	<li>At this point euthanize the animal or allow it to recover:
	<ol>
		<li>For euthanasia, perform cervical dislocation whilst still under anesthesia and collect organs of interest for subsequent analysis.</li>
		<li>If allowing the mouse to recover, place the mouse in single housing on a heating pad or in front of a heating lamp. Monitor the mouse until it has regained sufficient consciousness to maintain sternal recumbency. Allow the mouse to recover for 1 h before returning to group housing.</li>
	</ol>
	</li>
</ol>
4. PET Image Processing
NOTE: Image reconstruction was performed using acquisition workplace software v1.5.0.28 and analysis in research workplace software v4.2.
<ol>
	<li>Co-register CT and PET images and ensure that the alignment is correct in all 3 dimensions.
	<ol>
		<li>In the &#39;File&#39; menu, select &#39;Folder Search/Import&#39; and select the folder containing the data. Select the desired PET and CT data and click on the &#39;General Analysis&#39; tab.</li>
		<li>Sort the data so that the CR is designated &#39;Source&#39; and PET is designated &#39;Target&#39;. In the &#39;Workflow&#39; menu, select &#39;Registration&#39;. If the images require adjustment to be correctly co-registered, use the tools in the &#39;Registration&#39; menu.</li>
	</ol>
	</li>
	<li>In the &#39;Workflow&#39; menu, select &#39;ROI Quantification&#39;.
	<ol>
		<li>Use the &#39;Pan&#39; and &#39;Zoom&#39; functions in the &#39;Image&#39; tab to locate the desired region. In the &#39;Tools&#39; menu, select the &#39;Create&#39; tab and click the paintbrush icon. Draw the ROI on the image</li>
	</ol>
	</li>
	<li>Extract time-activity curves by selecting &#39;Save ROI Quantification&#39; from the &#39;Save&#39; menu. Save the data as a CSV file.</li>
	<li>Quantify radioactivity uptake as Bq per cm3 of tissue. Convert values into percentage of injected dose per cm3 (% ID/ cm3) by loading the CSV file into a spreadsheet.</li>
</ol>
5. Input Function
<ol>
	<li>To correct for the system point spread function, deconvolve the estimated system PSF for 5 iterations using the reblurred Van Cittert deconvolution method as previously described9. 
	NOTE: This is required due to the small size of the vena cava in a mouse.</li>
	<li>Use post deconvolution images to generate a blood input function time-activity curve as described above.</li>
</ol>
6. Kinetic Modeling
NOTE: The FDG two-tissue compartment model (Figure 1) requires the plasma input function.
<ol>
	<li>Convert the blood input function in the CSV file to the plasma input function using the following equation10: Input_plasma = Input_blood &#215; (0.386e&#8722;0.191t + 1.165).</li>
	<li>In the kinetic modelling tool click the &#39;Kinetic&#39; button. Import the tissue and plasma total activity count CSV files into the kinetic modelling tool by selecting &#39;Load Time Activity Curve&#39; from the &#39;Menu&#39;.</li>
	<li>In the &#39;Model&#39; menu select 2 tissue compartments. Ensure that the box next to k4 is unselected and enter a value of 0. For initial fitting, uncheck the box for vB (blood volume fraction) and enter a value of 2%.</li>
	<li>Click the &#39;Fit current region&#39;. Correct the extracted region of interest for dispersion11,12. Achieve this by minimizing the Chi-square value for the FDG model for different dispersion times.</li>
	<li>Perform a second fit using floating vB value (check the box next to the box for vB) and the optimized dispersion value to calculate the regional rate constants (k1-k3). Calculate the regional influx constant as Ki = (k1 &#215; k3) / (k2 + k3).</li>
</ol>

<ol><li>Jensen, M. M., Kjaer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Monitoring+of+anti-cancer+treatment+with+%2818%29F-FDG+and+%2818%29F-FLT+PET%3A+a+comprehensive+review+of+pre-clinical+studies%5BTitle%5D)+AND+%22Am+J+Nucl+Med+Mol+Imaging%22%5BJournal%5D)">Monitoring of anti-cancer treatment with (18)F-FDG and (18)F-FLT PET: a comprehensive review of pre-clinical studies.</a> Am J Nucl Med Mol Imaging. 5, 431-456 (2015).</li>
<li>Duncan, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((%2818%29F-FDG-PET%2FCT+imaging+in+an+IL-6-+and+MYC-driven+mouse+model+of+human+multiple+myeloma+affords+objective+evaluation+of+plasma+cell+tumor+progression+and+therapeutic+response+to+the+proteasome+inhibitor+ixazomib%5BTitle%5D)+AND+%22Blood+Cancer+J%22%5BJournal%5D)">(18)F-FDG-PET/CT imaging in an IL-6- and MYC-driven mouse model of human multiple myeloma affords objective evaluation of plasma cell tumor progression and therapeutic response to the proteasome inhibitor ixazomib.</a> Blood Cancer J. 3, e165(2013).</li>
<li>Wang, Y., Kung, A. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((18F-FDG-PET%2FCT+imaging+of+drug-induced+metabolic+changes+in+genetically+engineered+mouse+lung+cancer+models%5BTitle%5D)+AND+%22Cold+Spring+Harb+Protoc%22%5BJournal%5D)">18F-FDG-PET/CT imaging of drug-induced metabolic changes in genetically engineered mouse lung cancer models.</a> Cold Spring Harb Protoc. 2015, 176-179 (2015).</li>
<li>Wang, X., Minze, L. J., Shi, Z. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Functional+imaging+of+brown+fat+in+mice+with+18F-FDG+micro-PET%2FCT%5BTitle%5D)+AND+%22Journal+of+visualized+experiments+%3A+JoVE%22%5BJournal%5D)">Functional imaging of brown fat in mice with 18F-FDG micro-PET/CT.</a> Journal of visualized experiments : JoVE. , (2012).</li>
<li>Radu, C. G., Shu, C. J., Shelly, S. M., Phelps, M. E., Witte, O. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Positron+emission+tomography+with+computed+tomography+imaging+of+neuroinflammation+in+experimental+autoimmune+encephalomyelitis%5BTitle%5D)+AND+%22Proc+Natl+Acad+Sci+U+S+A%22%5BJournal%5D)">Positron emission tomography with computed tomography imaging of neuroinflammation in experimental autoimmune encephalomyelitis.</a> Proc Natl Acad Sci U S A. 104, 1937-1942 (2007).</li>
<li>Toba, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Post-natal+treatment+by+a+blood-brain-barrier+permeable+calpain+inhibitor%2C+SNJ1945+rescued+defective+function+in+lissencephaly%5BTitle%5D)+AND+%22Sci+Rep%22%5BJournal%5D)">Post-natal treatment by a blood-brain-barrier permeable calpain inhibitor, SNJ1945 rescued defective function in lissencephaly.</a> Sci Rep. 3, 1224(2013).</li>
<li>Halseth, A. E., Bracy, D. P., Wasserman, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Overexpression+of+hexokinase+II+increases+insulinand+exercise-stimulated+muscle+glucose+uptake+in+vivo%5BTitle%5D)+AND+%22Am+J+Physiol%22%5BJournal%5D)">Overexpression of hexokinase II increases insulinand exercise-stimulated muscle glucose uptake in vivo.</a> Am J Physiol. 276, E70-E77 (1999).</li>
<li>Defronzo, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Banting+Lecture.+From+the+triumvirate+to+the+ominous+octet%3A+a+new+paradigm+for+the+treatment+of+type+2+diabetes+mellitus%5BTitle%5D)+AND+%22Diabetes%22%5BJournal%5D)">Banting Lecture. From the triumvirate to the ominous octet: a new paradigm for the treatment of type 2 diabetes mellitus.</a> Diabetes. 58, 773-795 (2009).</li>
<li>Tohka, J., Reilhac, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Deconvolution-based+partial+volume+correction+in+Raclopride-PET+and+Monte+Carlo+comparison+to+MR-based+method%5BTitle%5D)+AND+%22NeuroImage%22%5BJournal%5D)">Deconvolution-based partial volume correction in Raclopride-PET and Monte Carlo comparison to MR-based method.</a> NeuroImage. 39, 1570-1584 (2008).</li>
<li>Wu, H. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((et+al.+In+vivo+quantitation+of+glucose+metabolism+in+mice+using+small-animal+PET+and+a+microfluidic+device%5BTitle%5D)+AND+%22J+Nucl+Med%22%5BJournal%5D)">et al. In vivo quantitation of glucose metabolism in mice using small-animal PET and a microfluidic device.</a> J Nucl Med. 48, 837-845 (2007).</li>
<li>Oikonen, V. Model equations for the dispersion of the input function in bolus infusion PET studies. , Available from:
 <a target="_blank" href="http://www.turkupetcentre.net/reports/tpcmod0003.pdf">http://www.turkupetcentre.net/reports/tpcmod0003.pdf</a> (2002).</li>
<li>Iida, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Error+analysis+of+a+quantitative+cerebral+blood+flow+measurement+using+H2%2815%29O+autoradiography+and+positron+emission+tomography%2C+with+respect+to+the+dispersion+of+the+input+function%5BTitle%5D)+AND+%22J+Cereb+Blood+Flow+Metab%22%5BJournal%5D)">Error analysis of a quantitative cerebral blood flow measurement using H2(15)O autoradiography and positron emission tomography, with respect to the dispersion of the input function.</a> J Cereb Blood Flow Metab. 6, 536-545 (1986).</li>
<li>Cochran, B. J., et al. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/27193916">In vivo PET imaging with [18F]FDG to explain improved glucose uptake in an apolipoprotein A-I treated mouse model of diabetes.</a> Diabetologia. 59, 1977-1984 (2016).</li>
<li>Kobayashi, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+db%2Fdb+mouse%2C+a+model+for+diabetic+dyslipidemia%3A+molecular+characterization+and+effects+of+Western+diet+feeding%5BTitle%5D)+AND+%22Metabolism%22%5BJournal%5D)">The db/db mouse, a model for diabetic dyslipidemia: molecular characterization and effects of Western diet feeding.</a> Metabolism. 49, 22-31 (2000).</li>
<li>Yue, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Magnetic+resonance+imaging+of+progressive+cardiomyopathic+changes+in+the+db%2Fdb+mouse%5BTitle%5D)+AND+%22Am+J+Physiol+Heart+Circ+Physiol%22%5BJournal%5D)">Magnetic resonance imaging of progressive cardiomyopathic changes in the db/db mouse.</a> Am J Physiol Heart Circ Physiol. 292, H2106-H2118 (2007).</li>
<li>Hagberg, C. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Targeting+VEGF-B+as+a+novel+treatment+for+insulin+resistance+and+type+2+diabetes%5BTitle%5D)+AND+%22Nature%22%5BJournal%5D)">Targeting VEGF-B as a novel treatment for insulin resistance and type 2 diabetes.</a> Nature. 490, 426-430 (2012).</li>
<li>Alf, M. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Quantification+of+brain+glucose+metabolism+by+18F-FDG+PET+with+real-time+arterial+and+image-derived+input+function+in+mice%5BTitle%5D)+AND+%22J+Nucl+Med%22%5BJournal%5D)">Quantification of brain glucose metabolism by 18F-FDG PET with real-time arterial and image-derived input function in mice.</a> J Nucl Med. 54, 132-138 (2013).</li>
<li>Tantawy, M. N., Peterson, T. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Simplified+%5B18F%5DFDG+image-derived+input+function+using+the+left+ventricle%2C+liver%2C+and+one+venous+blood+sample%5BTitle%5D)+AND+%22Molecular+imaging%22%5BJournal%5D)">Simplified [18F]FDG image-derived input function using the left ventricle, liver, and one venous blood sample.</a> Molecular imaging. 9, 76-86 (2010).</li>
<li>Thorn, S. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Repeatable+noninvasive+measurement+of+mouse+myocardial+glucose+uptake+with+18F-FDG%3A+evaluation+of+tracer+kinetics+in+a+type+1+diabetes+model%5BTitle%5D)+AND+%22J+Nucl+Med%22%5BJournal%5D)">Repeatable noninvasive measurement of mouse myocardial glucose uptake with 18F-FDG: evaluation of tracer kinetics in a type 1 diabetes model.</a> J Nucl Med. 54, 1637-1644 (2013).</li>
<li>Wagner, R., Zimmer, G., Lacko, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+interspecies+approach+to+the+investigation+of+the+red+cell+membrane+glucose+transporter%5BTitle%5D)+AND+%22Biochim+Biophys+Acta%22%5BJournal%5D)">An interspecies approach to the investigation of the red cell membrane glucose transporter.</a> Biochim Biophys Acta. 771, 99-102 (1984).</li>
<li>Flores, J. E., McFarland, L. M., Vanderbilt, A., Ogasawara, A. K., Williams, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+effects+of+anesthetic+agent+and+carrier+gas+on+blood+glucose+and+tissue+uptake+in+mice+undergoing+dynamic+FDG-PET+imaging%3A+sevoflurane+and+isoflurane+compared+in+air+and+in+oxygen%5BTitle%5D)+AND+%22Mol+Imaging+Biol%22%5BJournal%5D)">The effects of anesthetic agent and carrier gas on blood glucose and tissue uptake in mice undergoing dynamic FDG-PET imaging: sevoflurane and isoflurane compared in air and in oxygen.</a> Mol Imaging Biol. 10, 192-200 (2008).</li>
</ol>

The authors have nothing to disclose.

The protocol described here represents a robust, non-invasive methodology to determine the kinetics of glucose uptake from the blood stream into tissue and subsequent metabolism in mice.
The db/db mouse is a is a well-established animal model of type 2 diabetes14 that has been used extensively to examine insulin resistance and relevant interventions. However, previous studies have only quantified endpoint uptake in the heart15 and cardiac and ske...

The purpose of this study was to develop a positron emission tomography/computed tomography (PET/CT) based methodology to quantify the in vivo, real-time uptake of glucose from the blood stream into specific tissues in mice. This was achieved using 18F-labelled fluorodeoxyglucose (FDG) to measure glucose uptake and kinetic modelling to estimate the rates of 18F-FDG uptake from the plasma to the intracellular space, the rate of transport from intracellular space to plasma and the rate of 18F-FDG phosphorylation.
In rodents, 18F-FDG has been used in the pre-clinical assessment of numerous cancer treatments1, studies of tumor progression2 and tumor metabolism3 as well as imaging of brown fat depots4, neuroinflamation5 and brain metabolism6.
Traditional methods used to examine the tissue specific uptake of glucose in mice (and rats) generally involve treatment with 2-deoxyglucose radiolabeled with either 3H or 14C followed by euthanasia, tissue collection and measurement of radioactivity in each tissue7. The use of PET/CT allows for noninvasive determination of glucose uptake and metabolism in multiple organs and regions simultaneously in live animals. Additionally, as euthanasia is not a requirement, this technique is suitable for use in longitudinal studies.
Type 2 diabetes mellitus (T2DM) is characterized by disrupted glucose metabolism and hyperglycemia secondary to reduced tissue responsiveness to insulin (insulin resistance) and the inability of pancreatic -cells to produce adequate amounts of insulin8. Kinetic analysis of glucose uptake and metabolism can provide important insights into the mechanism of action and efficacy of therapeutic interventions as well as allow for advanced monitoring of disease progression.

<table><tbody><tr><td>PET/CT Scanner</td><td>Siemens</td><td>Inveon&amp;nbsp;</td><td></td></tr><tr><td>&lt;sup&gt;18&lt;/sup&gt;F-FDG</td><td>PETNET Solutions</td><td></td><td></td></tr><tr><td>Isoflurane</td><td>Pharmachem</td><td></td><td></td></tr><tr><td>30 guage needle</td><td>BD</td><td>305106</td><td></td></tr><tr><td>PMOD modelling software</td><td>PMOD Technologies</td><td></td><td></td></tr><tr><td>BKS.Cg-&lt;em&gt;Dock7m&lt;/em&gt;&amp;nbsp;+/+&amp;nbsp;&lt;em&gt;Leprdb/J&lt;/em&gt; mice</td><td>Jackson Laboratory</td><td>000642</td><td></td></tr><tr><td>Human insulin</td><td>Sigma-Aldrich</td><td></td><td></td></tr></tbody></table>

determining glucose metabolism kinetics using 18f-fdg micro-pet/ct

Determining Glucose Metabolism Kinetics Using 18F-FDG Micro-PET/CT

This paper describes the use of 18F-FDG and micro-PET/CT imaging to determine in vivo glucose metabolism kinetics in mice (and is transferable to rats). Impaired uptake and metabolism of glucose in multiple organ systems due to insulin resistance is a hallmark of type 2 diabetes. The ability of this technique to extract an image-derived input function from the vena cava using an iterative deconvolution method eliminates the requirement of the collection of arterial blood samples. Fitting of tissue and vena cava time activity curves to a two-tissue, three compartment model permits the estimation of kinetic micro-parameters related to the 18F-FDG uptake from the plasma to the intracellular space, the rate of transport from intracellular space to plasma and the rate of 18F-FDG phosphorylation. This methodology allows for multiple measures of glucose uptake and metabolism kinetics in the context of longitudinal studies and also provides insights into the efficacy of therapeutic interventions.

We have previously used the db/db mouse model to investigate the impact of increasing plasma apoA-I levels on the kinetics of glucose uptake and metabolism13. In this study we used db/db mice treated with insulin to demonstrate the utility of PET/CT imaging to monitor the uptake of 18F-FDG from the plasma into the gastrocnemius muscle in real time.
Six week old db/db mice were anesthetized and ...

This study describes a protocol that uses 18F-FDG and positron emission tomography/computed tomography (PET/CT) imaging, together with kinetic modelling, to quantify the in vivo, real-time uptake of 18F-FDG into tissues.

This paper describes the use of 18F-FDG and micro-PET/CT imaging to determine in vivo glucose metabolism kinetics in mice (and is transferable to rats). ...

The overall goal of this imaging protocol is to quantify the in vivo realtime uptake of glucose from the bloodstream into specific tissues in mice. This method can help answer key questions in the diabetes and metabolism field, such as the impact of any diabetic treatments on glucose uptake and metabolism. The main advantage of this technique is that experiments can be performed longitudinally to assess for example the impact of age or diet on glucose metabolism.Learning this method provides information about glucose metabolism in sclero muscle. It is also useful in other tissues such as liver and brain and is transferrable to rats. Visual demonstration of this method is critical, as the imaging acquisition and our analysis steps must be completed correctly to ensure accurate results.First, wipe down the induction chamber, the imaging bed, and the heat pad with 80%ethanol. Place the mouse subject in the induction chamber and anesthetize the mouse with 5%isoflurane and oxygen. Secure an electric heating pad and a sensor pad on the imaging bed.Place the mouse in a prone position and continue delivering one liter per minute of 1.5 to 2%isoflurane by a nose cone. Apply veterinary ointment to the mouse's eyes to prevent dryness. Then, warm the mouse's tail for one to two minutes.Once the lateral tail vein is dilated, insert a 30 gauge needle into the vein. Fix the needle in place with surgical glue and connect a catheter to the needle. Load the imaging bed into the PET/CT scanner and position the bed so the catheter is accessible from the rear of the machine.Secure a syringe containing the ten mega back roll F18-FDG dose to the catheter. After a set time following induction of anesthesia, start a one hour PET scan and inject the F18-FDG dose. Upon completion of the PET scan, perform a 10 minute CT scan.After the CT scan, move the imaging bed to its initial position and remove the mouse from the bed. Either euthanize the mouse by cervical dislocation under anesthesia, or allow the mouse to recover in single housing under observation. To begin the image processing, load the reconstructed PET and CT images.Designate the CT data as source and the PET data as target. Co-register the data and align the images as needed. Then, select ROI quantification.Use the panning and zoom tools to locate the desired region of interest in the image. Navigate to the create tab and select the paintbrush tool. Draw an ROI corresponding to the gastrocnemius muscle.Then, use the save ROI quantification function to extract the tissue time activity data as a CSV file. De-convolve the estimated system point spread function for five iterations with a Van Cittert deconvolution method. Next, draw an ROI corresponding to the vena cava.Export the blood input function time activity data from the post de-convolution images as a CSV file. Import the CSV files into spreadsheet software. Save the data as new CSV files and convert the uptake values to percent injected dose per centimeter cubed.Plot the time activity curves with the spreadsheet software. Next, save the processed vena cava data to a new CSV file. Convert the vena cava data to a plasma input function.Select kinetic in the kinetic modeling tool. Import the tissue and plasma total activity count data files. Choose a two tissue, three compartment model.Ensure that the F18-FDG dephosphorylation rate, K4, is unchecked and has a value of zero. Set the blood volume fraction, VB, to 2%To add dispersion to the vena cava derived input function, use a program such as disp4dft to create multiple input functions with different dispersion times. Then load the input functions with dispersion one by one and select fit current region.Repeat to find the input function with dispersion that has the lowest ChiSquared value. Using the optimized input function, set the blood volume fraction to a floating value. Fit the region again to determine the regional rate constants.Then calculate the regional influx constant. Six week old DBDB mice treated with either insulin or phosphate-buffered saline were imaged with this method. The insulin treated mice showed increased F18-FDG activity in the gastrocnemius muscle compared to the control mice.No increased activity was observed in the vena cava. A two tissue, three compartment model was used for kinetic modeling. No significant difference from control was observed in the rate of F18-FDG transport from arteriol plasma to the intracellular space or vice versa.However, the F18-FDG phosphorylation rate was significantly higher in the insulin-treated mice. The influx constant was correspondingly higher for the insulin-treated mice. After watching the video, you should have a good understanding of how to correctly image the mice, draw regions of interest, and calculate kinetic parameters.Don't forget that working with radiation can be hazardous and precautions such as proper training, use of shielding and monitoring of exposure should always be taken when performing this procedure.

determining-glucose-metabolism-kinetics-using-18f-fdg-micro-petct

Research

JoVE Journal

Medicine

There is great need to identify atherosclerosis non-invasively, and here we demonstrate how FDG-PET/CT can be used to detect and quantify atherosclerotic plaque activity and vascular inflammation.

Quantification of Atherosclerotic Plaque Activity and Vascular Inflammation using [18-F] Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG-PET/CT)

A method of functional imaging of mouse brown adipose tissue (BAT) is described in which cold-stimulated uptake of 18F-Fluorodeoxyglucose (FDG) in BAT is non-invasively assessed with a standardized micro-PET/CT protocol. This method is robust and sensitive to detect differences in BAT activities in mouse models.

Functional Imaging of Brown Fat in Mice with 18F-FDG micro-PET/CT

This article describes multimodality imaging of cancerous tissues with PET and CT diagnostic imaging by using a radiotracer 18F-FDG. Cancerous tissue with high glycolytic activity uptakes more 18F-FDG.

FDG Based PET/CT Scan: A Method of Using Radiotracer for Non-invasive Imaging of Tumor Metabolism

Small-animal positron emission tomography enables the assessment of the brain's two main energy substrates: glucose and ketones. In the present method, 11C-acetoacetate and 18F-fluorodeoxyglucose are injected sequentially in each animal, and their uptake is measured quantitatively in specific brain regions determined from the magnetic resonance images.

A Dual Tracer PET-MRI Protocol for the Quantitative Measure of Regional Brain Energy Substrates Uptake in the Rat

In this protocol, we describe how to utilize [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (18F-FDG PET/CT) imaging to measure the tumor metabolic response to the targeted therapy MLN0128 in a Kras/Lkb1 mutant mouse model of lung cancer and coupled imaging with high resolution ex vivo autoradiography and quantitative histology.

Utilizing 18F-FDG PET/CT Imaging and Quantitative Histology to Measure Dynamic Changes in the Glucose Metabolism in Mouse Models of Lung Cancer

[18F]-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is useful for studying glucose metabolism related to brain function. Here, we present a protocol for an [18F]FDG tracer set-up and semiquantitative assessment of the region-of-interest analysis for targeted brain areas associated with clinical manifestations in patients with severe traumatic brain injury.

Semi-quantitative Assessment Using [18F]FDG Tracer in Patients with Severe Brain Injury

Amplitude-based optimal respiratory gating (ORG) effectively removes respiratory-induced motion blurring from clinical 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) images. Correction of FDG-PET images for these respiratory motion artefacts improves image quality, diagnostic and quantitative accuracy. Removal of respiratory motion artefacts is important for adequate clinical management of patients using PET.

Management of Respiratory Motion Artefacts in 18F-fluorodeoxyglucose Positron Emission Tomography using an Amplitude-Based Optimal Respiratory Gating Algorithm

This manuscript describes two radiotracer administration protocols for FDG-PET (constant infusion and bolus plus infusion) and compares them to bolus administration. Temporal resolutions of 16 s are achievable using these protocols.

Radiotracer Administration for High Temporal Resolution Positron Emission Tomography of the Human Brain: Application to FDG-fPET

Functional imaging and quantitation of thermogenic adipose depots in mice using a micro-PET/MR imaging-based approach.

Visualization and Quantification of Brown and Beige Adipose Tissues in Mice using [18F]FDG Micro-PET/MR Imaging

Here, we present an experimental imaging protocol for the quantification of cardiac function and morphology using high-resolution positron emission tomography/computed tomography for small animals. Both mice and rats are considered, discussing the different requirements of computed tomography contrast agents for the two species.

High-Resolution Cardiac Positron Emission Tomography/Computed Tomography for Small Animals

The acquisition of dynamic positron emission tomography (PET) data and reconstruction into time frames allows for metabolic brain connectivity analysis at the single-subject level. We describe a method to acquire [18F]FDG dynamic PET data of the rat brain and obtain a connectivity matrix through the extraction of time-activity curves of volumes of interest.

Studying Metabolic Brain Connectivity Using 2-Deoxy-2-[18F]Fluoro-D-Glucose Dynamic Positron Emission Tomography at the Single-subject Level

Learn kinetic modeling of glucose metabolism using 18F-FDG micro-PET/CT imaging in mice. This protocol enables real-time quantification of tissue glucose uptake for diabetes and metabolic research.

Determining Glucose Metabolism Kinetics Using ¹⁸F-FDG Micro-PET/CT

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