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

PET based blood pool imaging tracers have tremendous potential for detection of vascular abnormalities. We synthesized 68Ga-1,4,7-triazacyclononane-1,4,7-triacetic acid-human serum albumin (68Ga-NOTA-HSA) (1a) towards use in blood pool imaging and compared it with 68Ga-1,4,7,10-tetraazacyclo-dodecane-1,4,7,10-tetraacetic acid-HSA (68Ga-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 68Ga-NOTA-HSA can be further investigated for clinical blood pool imaging applications.

To evaluate the MRI macroscopic and microscopic parameters of mesorectal vasculature in rectal cancer patients. 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. 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). 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. • 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.

We presented a 61-year-old man's surprising Tc-MDP whole-body blood pool superscan pattern with early unexpected generalized bone uptake. He complained of weakness and undesired weight loss with anemia and elevated erythrocyte sedimentation rate. As a malignancy workup in a patient without obvious suspicious origin, a whole-body Tc-MDP bone scan was requested. This unusual tracer distribution on blood pool imaging was very similar to the whole-body delayed scan except for visible kidneys.

Nanoparticulate imaging agents and therapeutics have proven to be valuable tools in preclinical cardiovascular disease research. Because of their distinct properties and significant functional versatility, nanoparticulate imaging agents afford certain capabilities that are typically not provided by traditional small molecule agents. This review is the second in a two-part series covering nanoparticulate imaging agents and theranostics. It highlights current examples of radiolabeled nanoparticulate probes in preclinical cardiovascular research and demonstrates their utility in applications such as blood pool imaging and molecular imaging of ischemia, angiogenesis, atherosclerosis, and inflammation. These agents provide valuable insight into the molecular and cellular mechanisms of cardiovascular disease and illustrate both the limitations and the significant potential of nanoparticles in diagnostic and therapeutic applications. Further technologic development to improve performance, address safety concerns, and fulfil regulatory obligations is required for clinical translation of these emergent technologies.

Magnetic particle imaging (MPI) is an emerging tomographic method that enables sensitive and fast imaging. It does not require ionizing radiation and thus may be a safe alternative for tracking of devices in the catheterization laboratory. The 3-D real-time imaging capabilities of MPI have been demonstrated in vivo and recent improvements in fast online image reconstruction enable almost real-time data reconstruction and visualization. Moreover, based on the use of different magnetic particle types for catheter visualization and blood pool imaging, multi-color MPI enables reconstruction of separate images for the catheter and the vessels from simultaneously measured data. While these are important assets for interventional imaging, MPI field generators can furthermore apply strong forces on a magnetic catheter tip. It is the aim of this paper to give a first demonstration of the combination of real-time multi-color MPI with online reconstruction and interactive field control for the application of forces on a magnetic catheter model in a phantom experiment.

Background Red blood cells (RBCs) labeled with single-photon emitters have been clinically used for blood-pool imaging. Although some PET tracers have been introduced for blood-pool imaging, they have not yet been widely used. The present study investigated the feasibility of labeling RBCs with 18F-2-deoxy-2-fluoro-D-glucose (18F-FDG) for blood-pool imaging with PET. RBCs isolated from venous blood of rats were washed with glucose-free phosphate-buffered saline and labeled with 18F-FDG. To optimize labeling efficiency, the effects of glucose deprivation time and incubation (labeling) time with 18F-FDG were investigated. Post-labeling stability was assessed by calculating the release fraction of radioactivity and identifying the chemical forms of 18F in the released and intracellular components of 18F-FDG-labeled RBCs incubated in plasma. Just after intravenous injection of the optimized autologous 18F-FDG-labeled RBCs, dynamic PET scans were performed to evaluate in vivo imaging in normal rats and intraabdominal bleeding models (temporary and persistent bleeding). Results The optimal durations of glucose deprivation and incubation (labeling) with 18F-FDG were 60 and 30 min, respectively. As low as 10% of 18F was released as the form of 18F-FDG from 18F-FDG-labeled RBCs after a 60-min incubation. Dynamic PET images of normal rats showed strong persistence in the cardiovascular system for at least 120 min. In the intraabdominal bleeding models, 18F-FDG-labeled RBC PET visualized the extravascular blood clearly and revealed the dynamic changes of the extravascular radioactivity in the temporary and persistent bleeding. Conclusions RBCs can be effectively labeled with 18F-FDG and used for blood-pool imaging with PET in rats. Electronic supplementary material The online version of this article (doi:10.1186/s13550-017-0266-3) contains supplementary material, which is available to authorized users.

Objective To measure left ventricular (LV) function parameters in heart of healthy rats by three different positron emission tomography (PET) imaging techniques and by magnetic resonance imaging (MRI). Methods ECG-gated microPET examinations were obtained in seven healthy rats with 2-deoxy-2-[18F]fluoro-d-glucose (FDG) for calculation of LV-function from the blood-pool phase of the dynamic recording (FDGBP), and also from the later myocardial uptake (FDGMyo). On subsequent days, we re-measured LV-function using the novel blood-pool tracer 68Ga-albumin (AlbBP) and again by FDG (FDGMyo2) in one setting. Cine-MRI examination provided the reference standard measurement. Results The mean LV ejection fractions (LVEF) were 56 ± 3 (FDGBP), 55 ± 3 (FDGMyo), 56 ± 3 (FDGMyo2), 57 ± 3 (AlbBP), and 57 ± 2 (MRI). There were good to excellent correlations found between the LVEF-values as compared to MRI reference standard for FDGBP (r = 0.71), FDGMyo (r = 0.86) and AlbBP (r = 0.88). Both of the blood-pool methods significantly overestimated the magnitudes of end-diastolic-volume and end-systolic-volume, whereas FDGMyo matched closely to the MRI reference standard. There was no significant bias for both blood-pool methods and a minor negative bias for FDGMyo regarding the LV ejection fraction (LVEF) when compared to cine-MRI results. There was no significant difference between the means of FDGMyo and FDGMyo2 (P = .50). Conclusions Relative to reference standard MRI measurements of LVEF, there was excellent agreement between PET-based measurements, notably for the novel blood-pool tracer 68Ga-albumin.

Background: Hyperthermia induces vasodilatation that reduces central blood volume (CBV), central venous pressure (CVP) and mean arterial pressure (MAP). Inhibition of atrial natriuretic peptide (ANP) could be a relevant homeostatic defense mechanism during hyperthermia with a decrease in CBV. The present study evaluated how changes in plasma ANP reflect the changes in CBV during hyperthermia. Methods: Ten healthy subjects provided with a water perfused body suit increased body core temperature 1 °C. In situ labeled autologous red blood cells were used to measure the CBV with a gamma camera. Regions of interest were traced manually on the images of the whole body blood pool scans. Two measures of CBV were used: Heart/whole body ratio and thorax/whole body ratio. CVP and MAP were recorded. Arterial (ANPart) and venous plasma ANP were determined by radioimmunoassay. Results: The ratio thorax/whole body and heart/whole body decreased 7 % and 11 %, respectively (p

In the last 30 years, nuclear medicine has paralleled other imaging fields with the development of 3-dimensional techniques, including single-photon emission computed tomography and positron emission tomography. However, conventional nuclear medicine planar scintigraphy remains a common procedure at most imaging centers. Gastrointestinal studies constitute a significant portion of these planar procedures. The most common gastrointestinal studies, including hepatobiliary, gastric emptying, and gastrointestinal bleeding evaluations, resemble their original protocol. However, serial improvements have optimized the diagnostic efficacy of these procedures. Conventional Technetium-99m sulfur colloid liver/spleen imaging and hepatic blood pool imaging with labeled red blood cells now mainly serve an adjunctive role in the evaluation of equivocal findings on computed tomography. Salivary gland imaging is a less commonly requested evaluation, but can be used to evaluate functional capacity in some disease entities.

The first cardiac images were produced using a rectilinear scanner but further advances were made with the development of more suitable radioactive tracers and more sophisticated imaging equipment. The invention of the Anger’s gamma camera in 1957 opened the door for rapid development, initially with blood pool imaging, progressing to myocardial imaging, cardiac PET, and the multi-faceted discipline that is now an essential part of clinical cardiology. This chapter will summarise the History of Nuclear Cardiology in the UK.

Vascular malformations and hemangiomas are common in children, but gastric hemangioma is extremely rare with less than 15 reported cases in the pediatric age group. Gastric hemangioma accounts for only 0.05% of all gastrointestinal neoplasms, and intra-abdominal hemangiomas are rarely found outside of the liver. We present a unique case of gastric hemangioma, and multiple hemangiomas were detected in a single scan by 99mTc-labeled RBC blood pool imaging. This case also depicts the incremental role of SPECT/CT over planar acquisition for detecting multiple hemangiomas, especially for those lesions located adjacent to physiological blood pool activity.

Organ-specific contrast agents were developed after conventional extracellular gadolinium chelates and there are fewer data about their safety. They belong to different classes of agent and therefore exhibit different physicochemical properties, modes of action, and metabolic pathways. Currently, agents for both hepatobiliary imaging and blood pool imaging are available commercially. Based on laboratory data, all these agents are considered to be in the ‘intermediate risk’ category for inducing NSF. NSF has not been reported after any of these agents, but clinical experience is extremely limited for two of them.

The application of liposomes as carriers for imaging agents is considered. Liposomes loaded with the appropriate contrast agents have been shown to be suitable for gamma-, magnetic resonance (MR), computed tomography (CT) and ultrasound imaging. The methods are briefly described to prepare liposomes loaded with different contrast agents, as well as some data on their biodistribution. The application of contrast-loaded liposomes for liver/spleen, tumor, lymph nodes, infection and inflammation sites, myocardial infarction, and blood pool imaging is briefly reviewed together with some data available on the use of liposome for the ophtalmological imaging. New trends in the use of contrast-loaded liposomes are also considered, such as the application of long-circulating polymer-modified liposomes for imaging purposes and development of new lipid-coated liposome-like contrast agents.

In 1971 and 1973, Drs Strauss and Zaret published the seminal descriptions of stress radionuclide myocardial perfusion imaging and of ECG-gated blood pool imaging, marking the beginning of what we know now as nuclear cardiology. In the later years (1975-1980), radionuclide cardiac imaging emerged as a distinct entity within the field of nuclear medicine. The publication by Dr Gould on pharmacologic stress perfusion imaging was also pivotal for the development of this field. Of relevance for later developments, it was predominantly cardiologists who investigated and introduced the use of nuclear medicine techniques for clinical imaging of the heart. At the national meetings of the American College of Cardiology (ACC) and the American Heart Association (AHA), an increasing number of scientific sessions were devoted to clinical applications of radionuclide cardiac imaging. However, the daylong symposium on cardiovascular imaging at the annual meeting of the Society of Nuclear Medicine (SNM) became the most important annual educational and scientific event for those involved in nuclear cardiac imaging. The increasing interest in Nuclear Cardiology led to the formation of the Cardiovascular (CV) Council of the SNM on November 12, 1985. Dr Elias Botvinick was the founder and the first president, who was joined by a small core group of mainly cardiologists. Subsequent presidents were all prominent investigators in the field of nuclear cardiology, and many of them were cardiologists (Table 1). With 1,012 members, the CV Council became the most dynamic and largest council of the SNM. Thirty-six percent of the members were nuclear physicians, 32% cardiologists, 22% technologists, and 10% representatives of industry. Nevertheless, cardiologists were the predominant forces within the CV Council with regard to educational and research activities. After several years of very successful and wellattended cardiovascular imaging symposia, many cardiac imaging investigators felt that nuclear cardiology should expand as a field on its own and become more widely inclusive to those physicians who were becoming interested in this area of medicine. Early attempts to develop this concept within the SNM were not very successful. The leadership of the SNM exercised their official power to limit the operation of the CV Council as a mainly educational activity for its own nuclear medicine community and obviously had no desire to initiate a separate and potentially independent professional society within its own ranks. To many of the members of the CV Council, it became increasingly clear that a more effective and likely independent representation might be needed to advance the field. It was also recognized that such an effort should include clear guidelines for clinical training and practice that would lead to more consistent quality of nuclear cardiology services. The lack of such standards and the perception that there was wide variation in the field of nuclear cardiology practice was felt to significantly harm its credibility.

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.

The results of routinely performed multigated blood pool studies (MUGA) were compared with the presence of postthoracotomy complications in 46 adult men in a retrospective chart review. Pulmonary function measurements were also examined in relation to the presence of complications experienced. There was only one death, but survivable complications were not predicted by the MUGA results. The addition of MUGA as a routine preoperative cardiac screening technique did not result in increased ability to predict postoperative cardiopulmonary complications.

The authors discuss radioisotope angiography and blood pool imaging for assessing radiation-induced injuries to the hands and the deterioration or improvement in status during follow-up. Two industrial radiographers in two separate accidents were exposed to 22 Ci to 25 Ci of a Co-60 for 2 to 3 minutes each in February 1985. Subsequently, besides routine clinical examinations and other tests, they underwent a series of amputations and grafts in the digits of the hands. A first-pass study with Tc-99m sodium pertechnetate followed by delayed RBC labeled blood pool imaging was performed in September 1988 in both patients. Both had a reduced flow of tracer to the more affected hand and the affected digits. A repeat study performed in March 1989 revealed improvement in perfusion to the more affected hand in the first patient and no change in the second. Delayed blood pool imaging did not reveal any change. The improvement in flow also coincided with the reduction of pain in the affected digits of the first patient. The authors conclude that isotope angiography followed by delayed blood pool imaging is a simple, noninvasive procedure to assess radiation-induced damage to extremities and to evaluate deterioration or improvement during follow-up.

Nanoparticles have now emerged as widely used diagnostic agents in biomedicine. They possess unique features that can be exploited with imaging. Among these are an increased sensitivity in detection through amplification of signal changes; a manipulation of surface structures and enhancement of uptake by selected cells (macrophages); altered pharmacokinetics allowing, for instance, their use as blood pool imaging agents; and physicochemical manipulations of energy (i.e., quantum dots). Specific aspects of nanoparticles are introduced to illustrate their use in biomedical imaging.

Our goal was to evaluate the impact of image fusion on the interpretation of indium-111 Prosta-Scint SPECT scans.Sixty-seven consecutive patients referred for rising prostate-specific antigen (PSA) levels after initial therapy for primary prostate cancer underwent SPECT 96 hr after infusion of (111)In Prosta-Scint, with simultaneous technetium-99m blood pool imaging. Volume data sets from the SPECT scans were then fused with those from CT and MR images of the pelvis using a 3D landmark-based warping program. The SPECT scans were initially interpreted without benefit of MRI or CT fusion. The fused Prosta-Scint MRI-CT volumes were reevaluated by a nuclear radiologist and an MRI radiologist. Independent reviews before and after fusion were available in these patients. Validation of results after fusion was performed through correlation with PSA changes after radiation therapy.Six patients with sites that could not be evaluated and three without their original Prosta-Scint scanning reports were excluded; thus, 58 patients were studied clinically. Seventy-four of 161 prefusion-positive sites were found to be negative after fusion. These 74 sites subsequently were identified primarily as showing bowel, vessel, or marrow uptake after fusion. In two patients, nodal disease was identified although the review before perfusion indicated none. Twenty-five patients previously thought to have nodal disease appeared to have only local disease after fusion. After local radiation therapy, PSA levels decreased in 12 of 25 patients, increased in five, and were unavailable in eight.Although Prosta-Scint SPECT alone can help in the proper management of recurrent prostate cancer, fusion with MRI-CT of the pelvis can improve the specificity of the examination.

Hemangioma is the most common benign liver tumor. Hepatic blood pool imaging is an effective technique with a specificity approaching 100%. Typically, hemangiomas are completely filled on hepatic blood pool imaging. However, incomplete fill-in can be seen in larger hemangiomas complicated with thrombosis, fibrosis, or bleeding. We report a hepatic cavernous hemangioma with atypical peripheral rim activity.

The noninvasive assessment of resting left ventricular performance has become an integral part of the evaluation of patients with known or suspected cardiac disease, having important diagnostic, therapeutic, and prognostic significance. This article details the wide range of clinical diagnostic possibilities available by dynamic imaging of myocardial function using scintigraphic techniques, including gated planar and tomographic blood pool imaging, first-pass radionuclide angiography, and gated tomographic perfusion imaging. The clinical and technical aspects described should be useful to the cardiologist intent upon supervising the performance of these tests, as well as providing their interpretation.

Fifteen patients underwent resting echocardiography (EC), ECG gated cardiac MR ventriculography (MRV) and blood pool planar and SPECT ventriculography (SPV) sequentially on the same day. In addition, 36 patients had sequential ECG gated blood pool and SPV and 20 normal volunteers, age > 18 years, had sequential ECG gated cardiac MRI performed on both Siemens closed, 1.5T, and open, 0.2T, magnets. Echocardiography was performed using a HP 5500 system equipped with an S4 transducer in 2D mode. MRV at 0.2T and 1.5T used a circular polarized body coil. Nuclear Medicine studies used 25 mCi Tc- 99m labeled red blood cells. Gated planar and SPV were acquired on a dual head Siemens E-Cam system. We have found that MRV affords the most accurate measurement of ventricular function. SPV and MRV provide similar estimations of left ventricular function (LVEF). Further, SPV consistently provides higher LVEF, as compared to the planar data simultaneously acquired. Observed significant differences in intermodality measurements indicate that follow up studies in patients, especially in patients whose management is critically dependent on functional measurement changes, should be monitored by one modality only.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Liposomes have been investigated extensively as carriers for drugs in attempts to achieve selective deposition and/or reduced toxicity. Liposomes radiolabeled with gamma emitters such as (67)Ga, (111)In and (99m)Tc, can be used for imaging purposes. Liposomes as formulated in the past, are rapidly taken up by cells of the mononuclear phagocyte system (MPS), primarily those located in liver and spleen. The recent development of long-circulating liposomes (LCLs), yielded liposomes that oppose recognition by the MPS. The development of these LCLs with enhanced circulatory half-lives has broadened the potential of liposomes to scintigraphically visualize pathologic processes in vivo. Liposomes have been proposed for tumor imaging, infection imaging and blood pool imaging. Strategies have been developed that allow rapid, easy and efficient labeling of preformed liposomes with (111)In and (99m)Tc. There is now a vast body of preclinical evidence showing that LCLs can be used to image a wide variety of tumors as well as inflammatory lesions. The first studies in patients show that radiolabeled liposomes can image tumor and inflammatory lesions with good sensitivity and good specificity. Here, the present status of liposome-based radiopharmaceuticals for scintigraphic application is reviewed.

Primary splenic tumors are very rare. The authors present a case of splenic hamartoma in which positive 99mTc-DTPA-HSA uptake was recognized with ultrasound, CT, MR and angiographic images. This case showed the need to consider hamartoma as well as hemangioma in the differential diagnosis of 99mTc-DTPA-HSA uptake in splenic tumors.

Hepatic hemangiomas are the most common benign tumors of the liver. They are usually single, small, and asymptomatic. However, giant hepatic hemangiomas have been reported in the past, usually detected as incidental findings. Radionuclide blood pool imaging studies are used to confirm the presence of a hemangioma. This report describes a case of a giant hepatic hemangioma detected using intravenous total-body arteriography, done as a part of radionuclide blood pool hemangioma study. This simple addition to the regular RBC blood pool hemangioma study helps to determine the size of the liver in the early arterial phase and shows obvious increased blood pool activity in the delayed phase. It is also useful in detecting lesions in other parts of the body when present.

A patient with suspected splenic hemangioma showed an area of absent radioactivity at the lower pole of the spleen on Tc-99m stannous colloid imaging. Increased activity was seen in the same area on Tc-99m RBC blood pool imaging. These findings were consistent with a splenic hemangioma.

Background To date, few PET tracers for in vivo labeling of red blood cells (RBCs) are available. In this study, we report the radiosynthesis and in vitro and in vivo evaluation of 11C and 18F sulfonamide derivatives targeting carbonic anhydrase II (CA II), a metallo-enzyme expressed in RBCs, as potential blood pool tracers. A proof-of-concept in vivo imaging study was performed to demonstrate the feasibility to assess cardiac function and volumes using electrocardiogram (ECG)-gated positron emission tomography (PET) acquisition in comparison with cine magnetic resonance imaging (cMRI) in rats and a pig model of myocardial infarction. Methods The inhibition constants (K i) of CA II were determined in vitro for the different compounds by assaying CA-catalyzed CO2 hydration activity. Binding to human RBCs was estimated after in vitro incubation of the compounds with whole blood. Biodistribution studies were performed to evaluate tracer kinetics in NMRI mice. ECG-gated PET acquisition was performed in Wistar rats at rest and during pharmacological stress by infusing dobutamine at 10 μg/kg/min and in a pig model of myocardial infarction. Left ventricular ejection fraction (LVEF) and volumes were compared with values from cMRI. Results The K i of the investigated compounds for human CA II was found to be in the range of 8 to 422 nM. The fraction of radioactivity associated with RBCs was found to be ≥90% at 10- and 60-min incubation of tracers with heparinized human blood at room temperature for all tracers studied. Biodistribution studies in mice indicated that 30% to 67% of the injected dose was retained in the blood pool at 60 min post injection. A rapid and sustained tracer uptake in the heart region with an average standardized uptake value of 2.5 was observed from micro-PET images. The LVEF values obtained after pharmacological stress in rats closely matched between the cMRI and micro-PET values, whereas at rest, a larger variation between LVEF values obtained by both techniques was observed. In the pig model, a good agreement was observed between PET and MRI for quantification of left ventricular volumes and ejection fraction. Conclusions The 11C and 18F sulfonamide derivatives can be used for efficient in vivo radiolabeling of RBCs, and proof-of-concept in vivo imaging studies have shown the feasibility and potential of these novel tracers to assess cardiac function.

Objectives. This study was designed to evaluate changes in ventricular volume, mass and cardiac function before and after creation of an atrial to pulmonary connection in patients with a univentricular atrioventricular connection. Background. Intact systolic and diastolic performance is critical for successful establishment of an atrial dependent circulation, and few studies are available comparing cardiac performance before and after creation. Methods. With the use of radionuclide blood pool imaging and ventricular cineangiography, 54 patients (mean age 6.4 ± 3.4 years) were studied. Twenty-eight patients were investigated preoperatively and 36 > 1 year after repair and compared with a control population. Results. Before operation, end-diastolic volume and wall mass were significantly increased compared with those of control subjects; however, the mass/volume ratio was normal (1.08 ± 0.31 g/ml for the preoperative group; 0.97 ± 0.19 for control subjects). Although end-diastolic volume returned to normal after the procedure, wall mass remained elevated and contributed to an elevated mass/volume ratio (1.20 ± 0.38 g/ml). After the procedure, systemic vascular resistance index was significantly elevated compared with that before surgery or with that of control subjects (1,199 ± 373,2,120 ± 645, 1,556 ± 275 dynes·s· cm-5·m2: pre- and posirepair and control subjects, respectively). Radionuclide studies demonstrated that preoperative ejection fraction (52 ± 9,50 ± 9,60 ± 8%), peak ejection (2.58 ± 0.66, 2.95 ± 0.81, 3.73 ± 0.70 EDV/s) and peak filling rates (2.84 ± 0.75, 2.75 ± 0.79, 3.84 ± 0.51 end-diastolic volumes [EDV/s]) were significantly reduced compared with those of contral subjects and remained so after surgery. Conclusions. These data suggest that systolic and diastolic function is depressed preoperatively in these patients, remains unchanged after the creation of an atrial-dependent circulation and is associated with an increased systemic vascular resistance. Long-term issues addressing preservation of cardiac function need to be prospectively studied.

Gallbladder visualization has been described during delayed Tc-99m RBC blood pool imaging in patients with some combination of anemia, renal disease, and multiple recent blood transfusions. The authors present two cases of gallbladder activity that appeared 1 hour after the injection of Tc-99m RBCs in patients without renal or hematologic abnormalities.

To determine whether endurance exercise training can improve left ventricular systolic function in older men, 10 healthy sedentary men (64 +/- 3 years old; mean +/- SD) were studied. Training consisted of endurance exercise 4 +/- 0.3 days per week for 11.8 +/- 2.5 months at a progressively increasing intensity of 60-80% of maximal O2 uptake (Vo2max) with additional brief bouts of exercise equal to 93 +/- 13% of Vo2max. Vo2max increased from 29.6 +/- 4.1 to 37.2 +/- 5.7 ml/kg/min (p less than 0.001). Percent body fat was decreased (17.8 +/- 3.6% versus 15.6 +/- 3.6%; p less than 0.001). Before training, left ventricular ejection fraction, determined by electrocardiographic-gated equilibrium blood pool imaging, increased only modestly during exercise (from 66.3 +/- 6.7% at rest to 70.6 +/- 6.9% at peak exercise). After training, the increase in ejection fraction during exercise was significantly greater (from 67 +/- 4.8% at rest to 77.6 +/- 7.5% at peak exercise) than that observed before training and was similar to that in young sedentary men (64 +/- 7% at rest versus 74 +/- 9% at peak exercise). Although the changes in systolic pressure from rest to exercise were similar, end-systolic volume decreased significantly at peak exercise after (51 +/- 12 versus 38 +/- 13 ml; p less than 0.005) but not before (46 +/- 8 versus 43 +/- 13 ml; p = NS) training with a shift in the end-systolic volume-systolic blood pressure relation to the left compatible with enhanced inotropic state.(ABSTRACT TRUNCATED AT 250 WORDS)

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 half-life 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.

Torsion of an epididymal appendix is one cause of acute hemiscrotum. The authors describe a 12-year-old boy who had two episodes of left scrotal pain within 10 days of hospital admission. Examination of the scrotum revealed a 3-mm dark spot on the skin overlying a tender nodule in the upper region on the left. A Tc-99m pertechnetate flow study and blood-pool images obtained 5 minutes later showed a linear hyperemic focus in the left upper hemiscrotum. Surgical exploration revealed torsion of a left epididymal appendix, which was removed and confirmed by histopathologic examination to be partially infarcted.

A focal hot area on Tc-99m blood pool imaging of the liver is usually indicative of a cavernous hemangioma. This report illustrates the unusual finding of a neoplastic cold area with a coexisting hot area from acute intrahepatic hemorrhage

The multiphase bone scan features of melorheostosis are presented. Early increased tracer delivery demonstrated by blood pool imaging supports the concept of ongoing accelerated bony metabolism as a cause of tracer uptake within the osteosclerotic lesions of melorheostosis. There is excellent correlation between the scintigraphic and radiographic distribution of these lesions.

A case of venous hemangioma in the premasseteric region of a 22-year-old man was reported. The chief complaint was a painless swelling in his right premasseteric region. His general condition was good. A thumb-tip-sized, elastic soft tumor, which fluctuated in size, was found at the premasseteric region. The first impression was hemangioma. CT-scan and ultrasonography revealed a soft tissue mass with several cystic spaces. Together with the findings of RI-angiography and blood pool imaging, a hemangioma was diagnosed. Under general anesthesia, the tumor was removed surgically by intra-oral approach. Histologically, it was diagnosed as a venous hemangioma.

Three methods for determining the left ventricular ejection fraction (EF) from R-wave synchronized blood-pool images were compared to contrast angiography; the reproducibility of these methods was established in 51 patients. The EF was systematically underestimated by the fixed region-of-interest (ROI) method compared to the two methods that used varying ROI's which track the left ventricular boundary. All methods correlated reasonably well with angiography and were highly reproducible. Use of varying ROI's resulted in EF values that were essentially identical to those determined by angiography. Resolution-recovery image processing appeared to improve reproducibility when varying ROI's were used.

SummaryThree cases of scintigraphic visualization of gynaecological tumours by 99mTc-HSA blood pool imaging are presented, i.e. one case of fibrothecoma (“cold” area visualization) and two cases of fibromyoma (“hot” area visualization). It is suggested that this technique may be useful in the preoperative evaluation of gynaecological tumours and their vascularity.

Using radionuclide blood pool imaging, we evaluated sequential changes in heart, lung, liver, and spleen intravascular volumes were evaluated before and during acute pericardial tamponade in 9 anesthetized dogs. Tamponade resulted in an abrupt (less than 1 min) decline in mean right heart (-30 +/- 5%, p less than 0.001 vs control) and left heart volumes (-27 +/- 4%, p less than 0.001 vs control), with a concomitant reduction in pulmonary volume (-17 +/- 3%, p less than 0.01 vs control). Within this short time frame, both hepatic (+19 +/- 3%) and splenic (+16 +/- 4%, both p less than 0.01 vs control) volumes rose. Five min after the production of tamponade, right and left heart volumes were still significantly reduced (-28 +/- 4, p less than 0.005 vs control and -23 +/- 2%, p less than 0.005 vs control), though pulmonary (+2 +/- 5%, p = NS vs control), hepatic (+7 +/- 3%, p less than 0.05 vs control) and splenic (+9 +/- 3%, p less than 0.05 vs control) volumes had returned toward baseline values. These volume changes were similar at 20 min after tamponade. Thus, tamponade resulted in a sudden shunting of blood from the central to the peripheral circulation, initially from both the lungs and heart. After 5 min pulmonary volumes returned to baseline values, while splenic and hepatic volumes remained slightly, though significantly elevated.

In four patients, each of whom had a different type of splenic cyst, 99mTc-sulphur colloid images revealed non-specific, intrasplenic "cold" lesions. The rim of splenic tissue surrounding the cyst was incomplete in three out of four patients and caused appearances similar to those of splenic infarction. Repeat spleen imaging with 99mTc-RBC revealed an additional cyst in one out of four patients. 113m indium blood pool images provided preoperative information on lesion vascularity. The scintigraphic diagnosis of splenic cysts should ideally combine 99mTc-sulphur colloid imaging, 99mTc-RBC imaging, and 113m Indium blood pool imaging.