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Magnetic resonance imaging (MRI) assessment of hepatic vasculature can be challenging in the setting of liver disease and liver lesions. The widely used hepatobiliary contrast agent gadoxetate is an extracellular contrast agent that provides excellent soft tissue characterization but has limitations as a vascular contrast agent. Ferumoxytol is an iron oxide nanoparticle with superparamagnetic properties that can be used as blood pool contrast agent to provide dedicated vascular assessment. We provide a detailed protocol for evaluation of pediatric liver vasculature using ferumoxytol, after imaging of the parenchyma with gadoxetate. We provide multiple examples and discuss practical considerations when incorporating ferumoxytol into practice. [ABSTRACT FROM AUTHOR]

Rapid and accurate assessment of conditions characterized by altered blood flow, cardiac blood pooling, or internal bleeding is crucial for diagnosing and treating various clinical conditions. While widely used imaging modalities such as magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound offer unique diagnostic advantages, they fall short for specific indications due to limited penetration depth and prolonged acquisition times. Magnetic particle imaging (MPI), an emerging tracer-based technique, holds promise for blood circulation assessments, potentially overcoming existing limitations with reduction in background signals and high temporal and spatial resolution, below the millimeter scale. Successful imaging of blood pooling and impaired flow necessitates tracers with diverse circulation half-lives optimized for MPI signal generation. Recent MPI tracers show potential in imaging cardiovascular complications, vascular perforations, ischemia, and stroke. The impressive temporal resolution and penetration depth also position MPI as an excellent modality for real-time vessel perfusion imaging via functional MPI (fMPI). This review summarizes advancements in optimized MPI tracers for imaging blood circulation and analyzes the current state of pre-clinical applications. This work discusses perspectives on standardization required to transition MPI from a research endeavor to clinical implementation and explore additional clinical indications that may benefit from the unique capabilities of MPI., (© 2024 Wiley‐VCH GmbH.)

18F-Labeled blood pool agents (BPAs) have attracted great attention for identifying bleeding sites. However, many BPAs are not sufficiently evaluated partially due to the limitations of labeling methods. In our previous work, we noticed that 18F-PEG1-vinyl sulfone (18F-VS) could efficiently label red blood cells (RBCs) ex vivo and in situ. However, its application as BPA is not fully evaluated. In this study, we systematically explored the feasibility of using 18F-VS-labeled RBCs as a positron emission tomography (PET) BPA for intra-abdominal bleeding diagnosis. In brief, we first optimized the labeling conditions, which lead to an 80% labeling yield of RBCs after incubating with 18F-VS in phosphate-buffered saline (PBS) at 37°C for 20 min. 18F-VS-labeled RBCs were found to be stable in vitro, which could simplify its transportation/storage for in vivo applications. In normal rat PET study, the cardiovascular system could be clearly imaged up to 5 h post injection (p.i.). An intra-abdominal hemorrhage rat model demonstrated that the 18F-VS-labeled RBCs clearly showed the dynamic changes of extravascular radioactivity due to intra-abdominal hemorrhage. Validation in the model of gastrointestinal bleeding clearly demonstrated the great potential of using 18F-VS-labeled RBCs as a BPA, which could be further evaluated in future studies.

A new protocol for rapid SPECT/CT blood pool imaging consisting of fewer image-angle acquisitions (fewer-angle SPECT/CT, or FASpecT/CT) was evaluated for localization of focal sites of soft-tissue inflammation, infection, and osteomyelitis. Methods: Immediately after dynamic flow and standard planar blood pool imaging with 99mTc-methylene diphosphonate, FASpecT/CT was performed with a dual-head γ-camera consisting of 6 steps over 360°, 12 total images with 30° of separation between angles, and 30 s per image, requiring a total imaging time of approximately 3 min. Images were reconstructed using iterative ordered-subset expectation maximization. Before use in a patient-care setting, various FASpecT/CT acquisition protocols were modeled using a phantom to determine the minimum number of stops and the stop duration required to produce a reliable image. Results: FASpecT/CT images provided excellent 3-dimensional localization of spine osteomyelitis, soft-tissue infection of the foot, and tendonitis of the hand and foot using a 3-min image acquisition time. The FASpecT/CT acquisition protocol required 1.3-3.5 min, including camera movement time. This was a reduction of 72%-90% from the time required for the standard 60-angle, 20-s SPECT/CT acquisition. Conclusion: The ability of FASpecT/CT blood pool images to help localize focal sites of hyperemia and inflammation can increase exam sensitivity and specificity. Additionally, using a FASpecT/CT protocol decreases imaging time by up to 90%. [ABSTRACT FROM AUTHOR]

PET based blood pool imaging tracers have tremendous potential for detection of vascular abnormalities. We synthesized Ga-1,4,7-triazacyclononane-1,4,7-triacetic acid-human serum albumin (Ga-NOTA-HSA) ( 1a) towards use in blood pool imaging and compared it with Ga-1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid-HSA (Ga-DOTA-HSA) ( 2a). Both 1a and 2a had similar biodistribution profiles with ≥70% ID/g activity in blood at 2 min p.i. About 50% of initial radioactivity was retained in blood at 2 h p.i. However, the plasma stability of 1a was superior to that of 2a. Results of our study indicate that Ga-NOTA-HSA can be further investigated for clinical blood pool imaging applications. [ABSTRACT FROM AUTHOR]

Purpose: Increased articular Tc MDP uptake on blood pool imaging (BPI) of patients with rheumatologic conditions is indicative of active inflammatory changes, and has been suggested as a strong predictor of response to radiosynoviorthesis (RSO). In this study, we aimed to assess the value of pretreatment BPI positivity (i.e. scintigraphic-apparent hyperemia) for successful RSO in hemophilic arthropathy. Methods: Thirty-four male patients with painful hemophilic arthropathy underwent RSO after failure of conservative treatment. Treated joints comprised the knee in eight, elbow in five, and ankle in 21 patients. Pretreatment triple-phase bone scintigraphy showed hyperemic joints (pathologic BPI) in 17 patients, whereas 17 patients had no increased tracer uptake on BPI. Response to RSO was evaluated 6 months post-treatment by measuring changes in intensity of arthralgia according to the visual analog scale (VAS), bleeding frequency, and range of motion. The association between hyperemia (pathologic BPI) and treatment outcome was examined using nonparametric tests for independent samples. Results: Clinically evident pain relief occurred in 26 patients (76.5 %), and the mean VAS decreased from 7.7 ± 1.1 to 4.6 ± 2.7 ( p < 0.001). Joint bleeding frequency (hemarthrosis) decreased from 4.5 ± 0.6 to 2.1 ± 0.4 during the first 6 months after RSO ( p < 0.001). For both parameters (pain relief and bleeding frequency), patients experienced a similar benefit from RSO regardless of pretreatment BPI: arthralgia ( p = 0.312) and frequency of hemarthrosis ( p = 0.396). No significant improvement was observed for range of motion, but it was significantly more restricted in hyperemic joints both before ( p = 0.036) and after treatment ( p = 0.022). Conclusions: Hemophilic arthropathy can be effectively treated with RSO regardless of pre-therapeutic BPI. Patients in whom articular hyperemia is not detectable by scintigraphy may have similar (outstanding) outcomes, and thus should not be excluded from treatment. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the MRI macroscopic and microscopic parameters of mesorectal vasculature in rectal cancer patients.Methods: Thirteen patients with rectal adenocarcinoma underwent a dynamic contrast-enhanced MRI at 1.5 T using a blood pool agent at the primary staging. Mesorectal macrovascular features, i.e., the number of vascular branches, average diameter and length, were assessed from baseline-subtracted post-contrast images by two independent readers. Mesorectal microvascular function was investigated by means of area under the enhancement-time curve (AUC). Histopathology served as reference standard of the tumour response to CRT.Results: The average vessel branching in the mesorectum around the tumour and normal rectal wall was 8.2 ± 3.8 and 1.7 ± 1.3, respectively (reader1: p = 0.001, reader2: p = 0.002). Similarly, the tumour-surrounding mesorectum displayed circa tenfold elevated AUC (p = 0.01). Interestingly, patients with primary node involvement had a twofold higher number of macrovascular branches compared to those with healthy nodes (reader1: p = 0.005 and reader2: p = 0.03). A similar difference was observed between good and poor responders to CRT, whose tumour-surrounding mesorectum displayed 10.7 ± 3.4 and 5.6 ± 1.5 vessels, respectively (reader1/reader2: p = 0.02).Conclusions: We showed at baseline MRI of rectal tumours a significantly enhanced macrovascular structure and microvascular function in rectal tumour-surrounding mesorectum, and the association of primary mesorectal macrovascular parameters with node involvement and therapy response.Key Points: • Vascular MRI reveals macrovascular and microvascular abnormalities in the rectal tumour-surrounding mesorectum. • Formation of highly vascular stroma precedes the actual tumour invasion. • High macrovascular parameters are associated with node involvement. • Mesorectal vascular network differs for good and poor responders. [ABSTRACT FROM AUTHOR]

A novel MRI blood-pool contrast agent (Gd-AAZTA-MADEC) has been compared with established blood pool agents for tumor contrast enhanced images and angiography. Synthesis, relaxometric properties, albumin binding affinity and pharmacokinetic profiles are reported. For in vivo studies, angiographic images and tumor contrast enhanced images were acquired on mice with benchtop 1T-MRI scanners and compared with MS-325, B22956/1 and B25716/1. The design of this contrast agent involved the elongation of the spacer between the targeting deoxycholic acid moiety and the Gd-AAZTA imaging reporting unit that drastically changed either the binding affinity to albumin (K A (HSA) = 8.3 × 10 5 M −1 ) and the hydration state of the Gd ion (q = 2) in comparison to the recently reported B25716/1. The very markedly high binding affinity towards mouse and human serum albumins resulted in peculiar pharmacokinetics and relaxometric properties. The NMRD profiles clearly indicated that maximum efficiency is attainable at magnetic field strength of 1 T. In vivo studies showed high enhancement of the vasculature and a prolonged accumulation inside tumor. The herein reported pre-clinical imaging studies show that a great benefit arises from the combination of a benchtop MRI scanner operating at 1 T and the albumin-binding Gd-AAZTA-MADEC complex, for pursuing enhanced angiography and improved characterization of tumor vascular microenvironment. [ABSTRACT FROM AUTHOR]

In-vitro labeling of RBC with 99mTc is an intricate procedure and there is always a need for an alternate blood pool imaging agent. The aim of this study was to prepare an effective nano sized liposome (NLs) similar to human RBC for blood pool scintigraphy. This study formulates PEG-NLs and non-PEG-NLs using film method plus high pressure homogenization technique. Biodistribution studies were performed on BALB/C mice 1, 4 and 24 h after tail vein injection of labeled NLs with 99mTc hexamethylpropylene-amine-oxime (99mTc-HMPAO). Planar images were acquired using a 256 × 256 matrix following99m Tc-HMPAO-NLs injection into ear vein of rabbits 1, 2 and 24 h later. SPECT images were obtained 15 minutes after the injection (64 slices, 30 second/projection). The mean diameter, zeta potential and polydispersity index (PDI) of the PEG-NLs and the NLs were (80.88 ± 0.594 nm, -12.5 ± 0.56 mv, 0.158 ± 0.025) and (94.14 ± 0.114 nm, -35.5 ± 0.67 mv and 0.198 ± 0.007), respectively. 99mTc-HMPAO-PEG-NLs showed a significant circulation tracer activity (7.74 ± 1.63%ID/g at 1 h and 4.9 ± 0.77%ID/g at 4 h), with low liver accumulation (12.07 ± 3.66%ID/g at 1 h and 14.85 ± 1.3%ID/g at 4 h). Heart to liver, spleen and background ROIs (region of interests) for 99m Tc-HMPAO-PEG-NLs were 1.25, 4 and 4.28 respectively at 2 h which changed to 1.06, 1.75 and 2.51 respectively at 24 h. The 99mTc-HMPAO-PEG-NLs with a prolonged blood circulation time could be an excellent RBC alternative for scintigraphy and gastrointestinal bleeding. [ABSTRACT FROM AUTHOR]

We sought to develop a practical, reproducible and clinically translatable method of radiolabeling serum albumins with fluorine-18 for use as a PET blood pool imaging agent in animals and man. Fluorine-18 radiolabeled fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester, [ 18 F]F-Py-TFP was prepared first by the reaction of its quaternary ammonium triflate precursor with [ 18 F]tetrabutylammonium fluoride ([ 18 F]TBAF) according to a previously published method for peptides, with minor modifications. The incubation of [ 18 F]F-Py-TFP with rat serum albumin (RSA) in phosphate buffer (pH 9) for 15 min at 37–40 °C produced fluorine-18-radiolabeled RSA and the product was purified using a mini-PD MiniTrap G-25 column. The overall radiochemical yield of the reaction was 18–35% (n = 30, uncorrected) in a 90-min synthesis. This procedure, repeated with human serum albumin (HSA), yielded similar results. Fluorine-18-radiolabeled RSA demonstrated prolonged blood retention (biological half-life of 4.8 hours) in healthy awake rats. The distribution of major organ radioactivity remained relatively unchanged during the 4 hour observation periods either by direct tissue counting or by dynamic PET whole-body imaging except for a gradual accumulation of labeled metabolic products in the bladder. This manual method for synthesizing radiolabeled serum albumins uses fluorine-18, a widely available PET radionuclide, and natural protein available in both pure and recombinant forms which could be scaled up for widespread clinical applications. These preclinical biodistribution and PET imaging results indicate that [ 18 F]RSA is an effective blood pool imaging agent in rats and might, as [ 18 F]HSA, prove similarly useful as a clinical imaging agent. [ABSTRACT FROM AUTHOR]

Introduction We describe and illustrate a method for creating ECG-gated PET images of the heart for each of several mice imaged at the same time. The method is intended to increase "throughput" in PET research studies of cardiac dynamics or to obtain information derived from such studies, e.g. tracer concentration in end-diastolic left ventricular blood. Methods An imaging bed with provisions for warming, anesthetic delivery, etc., was fabricated by 3D printing to allow simultaneous PET imaging of two side-by-side mice. After electrode attachment, tracer injection and placement of the animals in the scanner field of view, ECG signals from each animal were continuously analyzed and independent trigger markers generated whenever an R-wave was detected in each signal. PET image data were acquired in "list" mode and these trigger markers were inserted into this list along with the image data. Since each mouse is in a different spatial location in the FOV, sorting of these data using trigger markers first from one animal and then the other yields two independent and correctly formed ECG-gated image sequences that reflect the dynamical properties of the heart during an "average" cardiac cycle. Results The described method yields two independent ECG-gated image sequences that exhibit the expected properties in each animal, e.g. variation of the ventricular cavity volumes from maximum to minimum and back during the cardiac cycle in the processed animal with little or no variation in these volumes during the cardiac cycle in the unprocessed animal. Conclusion ECG-gated image sequences for each of several animals can be created from a single list mode data collection using the described method. In principle, this method can be extended to more than two mice (or other animals) and to other forms of physiological gating, e.g. respiratory gating, when several subjects are imaged at the same time. [ABSTRACT FROM AUTHOR]

Abstract: Nanoparticles that circulate in the bloodstream for a prolonged period of time have important biomedicine applications. However, no example of lanthanide-based nanoparticles having a long-term circulation bloodstream has been reported to date. Herein, we report on difunctional radioactive and upconversion nanoparticles (UCNP) coated with polyphosphoric acid ligand, that is ethylenediamine tetramethylenephosphonic acid (EDTMP), for an application in single-photon emission computed tomography (SPECT) blood pool imaging. The structure, size and zeta-potential of the EDTMP-coated nanoparticles (EDTMP-UCNP) are verified using transmission electron microscopy and dynamic light scattering. Injection of radioisotope samarium-153-labeled EDTMP-UCNP (EDTMP-UCNP:153Sm) into mice reveal superior circulation time compared to control nanoparticles coated with citric acid (cit-UCNP:153Sm) and 153Sm complex of EDTMP (EDTMP-153Sm). The mechanism for the extended circulation time may be attributed to the adhesion of EDTMP-UCNP on the membrane of red blood cells (RBCs). In vivo toxicity results show no toxicity of EDTMP-UCNP at the dose of 100 mg/kg, validating its safety as an agent for blood pool imaging. Our results provide a new strategy of nanoprobe for a long-term circulation bloodstream by introducing polyphosphoric acid as surface ligand. [Copyright &y& Elsevier]

The usefulness of whole-body blood pool imaging as part of Tc-99m methylene diphosphonate (MDP) skeletal scintigraphy in detection of marrow infiltrative processes and unexpected soft-tissue and visceral abnormalities is demonstrated via illustrative case examples. Technical aspects of this simple and fast scanning technique are also highlighted. [ABSTRACT FROM AUTHOR]

Abstract: Although polymeric magnetic resonance imaging (MRI) agents have significantly improved relaxivity and prolonged circulation time in vivo compared with current imaging agents, the potential for long-term toxicity prevents their translation into the clinic. The aim of this study was to develop a new biodegradable, nonionic polymeric blood pool MRI contrast agent with efficient clearance from the body. We synthesized PHPG-DTPA, which possesses two potentially degradable sites in vivo: protein amide bonds of the polymer backbone susceptible to enzymatic degradation and hydrolytically labile ester bonds in the side chains. After chelation with Gd3+, PHPG-DTPA-Gd displayed an R1 relaxivity of 15.72 mm −1⋅sec−1 (3.7 times higher than that of MagnevistT). In vitro, DTPA was completely released from PHPG polymer within 48 h when incubated in mouse plasma. In vivo, PHPG-DTPA-Gd was cleared via renal route as shown by micro-single photon emission computed tomography of mice after intravenous injection of 111In-labeled PHPG-DTPA-Gd. MRI of nude rats bearing C6 glioblastoma showed significant enhancement of the tumor periphery after intravenous injection of PHPG-DTPA-Gd. Furthermore, mouse brain angiography was clearly delineated up to 2 h after injection of PHPG-DTPA-Gd. PHPG-DTPA-Gd’s biodegradability, efficient clearance, and significantly increased relaxivity make it a promising polymeric blood pool MRI contrast agent. [Copyright &y& Elsevier]

Abstract: Purpose: Currently, in vivo or in vitro 99mTc-radiolabelled red blood cells are the standard blood pool imaging agents. Due to risks associated with handling of blood and the problems with the current 99mTc shortage, we were interested in a long-circulating biocompatible synthetic macromolecule that would be simple to prepare and could also be used for PET imaging. Methods: A high molecular weight hyperbranched polyglycerol (HPG) of 500kDa was derivatized to coordinate radioactive gallium and to establish its labelling efficiency, stability and pharmacokinetics. Results: The resulting radiopharmaceutical in kit form was labelled rapidly within a couple of minutes at room temperature, was stable in transferrin and EDTA challenge tests, and was non-toxic in both cell viability and different hemocompatibility assays. A pharmacokinetic biodistribution study showed that the 67Ga–HPGN was confined to the blood compartment with a biological half life of 50.7h. Conclusion: 67Ga–HPGN is thus a simple to prepare blood pool imaging agent for applications where a long biological half-life is essential, i.e., the diagnosis of internal bleeding. Since radiolabelling of the same kit with 68Ga was also confirmed, we plan to evaluate it shortly as a PET blood pool imaging agent for cardiac applications. [Copyright &y& Elsevier]

Cardiovascular nuclear medicine procedures are useful to characterize coronary artery disease by measuring changes in perfusion, myocardial metabolism, cellular integrity, and regional or global function. Coronary angiography, while an excellent indicator of anatomic changes in arterial lumenal diameter, is a poor predictor of downstream perfusion, since neither the length of the stenosis nor absolute lumenal diameter is considered. Even if the anatomy is known, perfusion measurements provide information about ischaemia and ventricular dysfunction that is helpful for planning therapy. New technetium 99m-labelled perfusion agents are likely to improve the certainty of diagnosis due to their higher photon flux. The development of techniques for continuous ventricular function monitoring during daily activities provides an opportunity for detecting the impact of silent ischaemia on cardiac function. The role of the radionuclide imaging procedures in classifying patients with coronary disease is discussed in light of the pathophysiology of ischaemia and necrosis. [ABSTRACT FROM AUTHOR]

A new, single bolus method of in vivo blood pool imaging using a technetium Tc99m phosphine isocyanide complex (DEPIC) which binds to pre-albumin was evaluated in volunteers ( n=4) and patients ( n=20). DEPIC was assessed for its safety and possible drug interactions. Its duration of action and quality of ventriculography were compared with imaging using standard in vivo red cell labelling (PYP) during two 3-h scanning periods 1 week apart. DEPIC had a mean plasma halflife of 3.3 h. The count rate over the left ventricle was initially 42% higher with DEPIC than with PYP. However, removal of DEPIC by the liver resulted in equivalent count rates by 1 h, and by 3 h PYP count rates were 22% higher than DEPIC. Immediately post injection mean (SD) difference in the left ventricular ejection fraction between the two methods was 2.4% (7.7%). Satisfactory DEPIC scans were obtained up to 2 h post injection, but by 3 h there was a mean difference of 13% (11.3%). DEPIC was found to be a safe alternative to red all labelling for blood pool angiography, suitable for routine work. The single bolus methodology and high initial count rates offer improved efficiency and a capability for truly emergency scanning. [ABSTRACT FROM AUTHOR]

A new Tc-phosphine-isocyanide complex with the general structure [Tc (DEPE) (CNR)] has been synthesised and tested in animals and one human. In three animal species (rat, rabbit, dog), the complex is an efficient myocardial imaging agent, while in humans it remains in the blood pool. The complex is 100% protein bound in animals and humans, but whereas in humans it is attached to a 51.5 kdalton protein (probably prealbumin), in rabbits it appears to be bound to a larger macromolecule (M.W.> 100 kdalton). The efficiency of the complex for blood pool labelling was tested in a human volunteer and compared with the standard in vivo red cell labelling technique with stannous pyrophosphate. A satisfactory radionuclide angiogram could be performed with less than 370 MBq of the complex. The count rate for the complex (cps/MBq) was 15% higher than that obtained with the labelled red cells and the absence of splenic activity was notable. In humans this complex appears to be an efficient blood pool labelling agent which might be useful for radionuclide ventriculography. [ABSTRACT FROM AUTHOR]

ABSTRACT Technetium-99m planar sulfur colloid scintigraphy, red blood cell imaging and ultrasonography were performed in eighteen patients of hepatic hemangioma to evaluate their diagnostic utility. Radiocolloid scans detected fourteen hemangiomas in 12 patients as focal hepatic defects but missed 9 lesions smaller than 2.5cm in the other 6 patients, accounting for a 61% sensitivity. All 23 lesions were avascular or normovascular on radionuclide flow study. Serial planar red blood cell scintigraphy showed characteristic gradually increasing focal isotopic accumulation in the 14 hemangiomas which had identifiable cold areas on the radiocolloid study. One of 6 patients with normal radiocolloid scan also showed the typical increasing blood pool pattern of hemangioma, five had normal planar scans till 11/2 hours. SPECT red blood cell imaging in these 5 patients detected an additional seven hemangiomas. All 7 lesions were smaller than 2.5cm. One 1.5cm hemangioma was missed on both planar and SPECT red blood cell imaging. Region of interest ratios in SPECT transaxial images confirmed gradually increasing concentration of labeled red blood cells in the lesions. Ultrasonography detected 22 of the 23 hemangiomas. Ten were hyperechoic, average size 2.25cm. Twelve were of mixed pattern, generally larger, average size 7.2cm. Sonography is useful in the detection of hepatic hemangiomas as a focal mass lesion, but the variable sonographic appearance precludes a definite pathological diagnosis. Technetium-99m red blood cell imaging appears a sensitive technique in detection of hepatic hemangioma, with SPECT being especially useful in locating smaller lesions. The addition of SPECT to planar red blood cell imaging considerably improves the sensitivity of this highly specific technique for an accurate non-invasive diagnosis in hepatic hemangioma. [ABSTRACT FROM AUTHOR]

A 31-year-old woman presented with general malaise, back pain, and edema of the lower extremities. A chest X-ray film showed an enlarged cardiac shadow and clear lung fields. A pericardial lesion with decreased activity on blood pool imaging and increased uptake on gallium citrate imaging displaced the heart upwards and to the left. The pericardial mass showed an inhomogencous signal intensity on MRI and was large enough to obstruct the venous return by compressing the heart. At operation, the mass was found to originate from the pericardium and was histologically identified as a malignant fibrosarcoma. Twelve years previously, the patient had undergone an operation for the removal of a pericardial tumor which was histologically identified as a benign hemangioma. In view of the rarity of pericardial tumors, the present tumor is suspected to have undergone a transformation from benign hemangioma to malignant fibrosarcoma. [ABSTRACT FROM AUTHOR]

Nuclear blood pool imaging using radiolabeled red blood cells has been used in the clinical setting for the evaluation of a number of medical conditions including gastrointestinal hemorrhage, impaired cardiac contractility, and altered cerebrovascular blood flow. Nuclear blood pool imaging is typically performed using Technetium-99m-labeled ( 99m Tc) human erythrocytes ( i.e. , the "tagged RBC" scan) and gamma camera-based planar scintigraphic imaging. When compared to typical clinical planar scintigraphy and single-photon emission computed tomographic (SPECT) imaging platforms, positron emission tomography (PET) provides superior image quality and sensitivity. A number of PET-based radionuclide agents have been proposed for blood pool imaging, but none have yet to be used widely in the clinical setting. In this protocol, we described a simple and fast procedure for imaging the vasculature of immunodeficient mice through a combination of a small animal positron emission tomography/computed tomography (PET/CT) scanner and human erythrocytes labeled with the PET tracer 2-deoxy-2-( 18 F)fluoro-D-glucose ( 18 F-FDG). This technique is expected to have significant advantages over traditional 99m Tc -labeled erythrocyte scintigraphic nuclear imaging for these reasons., Competing Interests: Competing interestsA provisional international patent application was submitted by the H. Lee Moffitt Cancer Center and Research Institute describing the imaging technique outlined in the manuscript (WO Application number WO2017123666A2; PCT/US2017/013063 filed on 2017-01-11). No additional declarations or potential competing interests are made with regards to the patent application by the authors of the manuscript. This does not alter our adherence to PLOS ONE policies on sharing data and materials., (Copyright © 2019 The Authors; exclusive licensee Bio-protocol LLC.)