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H William Strauss

Publications and source records attributed to H William Strauss.

At least 19 recordsLinked to original sources
PubMed2007

99mTc-Annexin A5 for noninvasive characterization of atherosclerotic lesions: imaging and histological studies in myocardial infarction-prone Watanabe heritable hyperlipidemic rabbits.

PURPOSE: Apoptosis is commonly observed in advanced atherosclerotic lesions. 99mTc-annexin A5 (99mTc-annexin V) has been proposed as a potential tracer for imaging apoptosis in atherosclerotic plaques. Accordingly, we determined the usefulness of 99mTc-annexin A5 as an atherosclerosis imaging tracer in a rabbit model (myocardial infarction-prone Watanabe heritable hyperlipidemic rabbits; WHHLMI rabbits) of spontaneous atherosclerosis. METHODS: The WHHLMI and control rabbits were injected intravenously with 99mTc-annexin A5. After in vivo planar imaging, the radioactivity in the aorta was measured. Autoradiography, TUNEL staining, Azan-Mallory staining and immunohistological studies were performed serially throughout the aorta. RESULTS: 99mTc-Annexin A5 accumulation in the aorta of the WHHLMI rabbits was 5.6-fold higher than in that of control rabbits. Autoradiography showed heterogeneous multifocal accumulation of 99mTc-annexin A5 in WHHLMI rabbits. 99mTc-Annexin A5 accumulation was highest in the atheromatous lesions (6.2+/-2.5, %IDxBW/mm2x10(3)), followed in decreasing order by neointimal (4.9+/-1.3), fibroatheromatous (4.5+/-1.9), and collagen-rich lesions (3.3+/-1.4). The regional 99mTc-annexin A5 accumulation was significantly correlated with the TUNEL-positive cell density, macrophage density and "vulnerability index," an index of the morphological destabilized characteristics. The in vivo imaging clearly visualized the atherosclerotic lesions in WHHLMI rabbits. CONCLUSION: The present study in WHHLMI rabbits showed higher 99mTc-annexin A5 accumulation in grade IV atheroma than in other more stable lesions. 99mTc-Annexin A5 may be useful in identifying atheroma that is at higher risk for rupture and possibly in assessing the response to anti-atherosclerotic therapy.

Animals↗
PubMed2007

Screening for coronary artery disease after mediastinal irradiation for Hodgkin's disease.

PURPOSE: Incidental cardiac irradiation during treatment of thoracic neoplasms has increased risks for subsequent acute myocardial infarction or sudden cardiac death. Identifying patients who have a high risk for a coronary event may decrease morbidity and mortality. The objective of this study was to evaluate whether stress imaging can identify severe, unsuspected coronary stenoses in patients who had prior mediastinal irradiation for Hodgkin's disease. PATIENTS AND METHODS: We enrolled 294 outpatients observed at a tertiary care cancer treatment center after mediastinal irradiation doses 35 Gy for Hodgkin's disease who had no known ischemic cardiac disease. Patients underwent stress echocardiography and radionuclide perfusion imaging at one stress session. Coronary angiography was performed at the discretion of the physician. RESULTS: Among the 294 participants, 63 (21.4%) had abnormal ventricular images at rest, suggesting prior myocardial injury. During stress testing, 42 patients (14%) developed perfusion defects (n = 26), impaired wall motion (n = 8), or both abnormalities (n = 8). Coronary angiography showed stenosis 50% in 22 patients (55%), less than 50% in nine patients (22.5%), and no stenosis in nine patients (22.5%). Screening led to bypass graft surgery in seven patients. Twenty-three patients developed coronary events during a median of 6.5 years of follow-up, with 10 acute myocardial infarctions (two fatal). CONCLUSION: Stress-induced signs of ischemia and significant coronary artery disease are highly prevalent after mediastinal irradiation in young patients. Stress testing identifies asymptomatic individuals at high risk for acute myocardial infarction or sudden cardiac death.

Adult↗
PubMed2006

Radiation exposure of computed tomography and direct intracoronary angiography: risk has its reward.

A hallmark of noninvasive testing has been the identification of patients with coronary artery disease. Now, with multislice computed tomography (MSCT), information about coronary anatomy can be obtained without the need for catheterization. A major concern with the application of MSCT coronary angiography is the radiation exposure to the patient. Both MSCT and selective coronary angiography share the risks of procedure-related complications, such as allergic contrast reactions, and stochastic risks (i.e., cancer induction) of low-level radiation. There is a substantially higher radiation dose for MSCT angiography (effective dose [ED] 14 mSv) than for CCA (ED 6 mSv). These exposures yield lifetimes risks of 0.07% and 0.02%, respectively, of inducing a fatal cancer in the general (i.e., age- and gender-averaged) population. However, CCA poses additional serious risks associated with cardiac catheterization, yielding a non-radiogenic risk of mortality--excluding contrast reactions--of 0.11%. Combining the radiogenic and non-radiogenic risks (0.02% and 0.11%, respectively) yields a 0.13% overall risk of mortality from CCA--nearly two-fold higher than that for MSCT angiography (0.07%). If one were to use the lower, more age-appropriate risk factors for the older patient population in question, the radiogenic risks of both CCA and MSCT would be reduced by about one-half, further widening the overall safety ratio of MSCT relative to CCA. When weighing the relative risks of alternative medical procedures, therefore, it is imperative that one consider the overall risk of the respective procedures.

Coronary Angiography↗
PubMed2006

Intravascular radiation detectors for the detection of vulnerable atheroma.

An intravascular catheter was developed to identify inflammation in coronary atheroma. Inflammation in atheroma is associated with large numbers of macrophages. These cells have increased metabolism, increased expression of chemotactic receptors, and a high frequency of apoptosis-associated phosphatidylserine expression. Each of these parameters can be identified in vivo using specific radiolabeled agents: metabolism can be identified with 18F fluorodeoxyglucose (FDG), receptor expression with 99mTc monocyte chemotactic peptide-1, and apoptosis with 99mTc annexin V. The locally increased concentration of these tracers is readily demonstrable in experimental lesions by ex vivo autoradiography; however, the small lesion size makes it difficult to identify atheroma in the coronaries with conventional imaging equipment. In contrast, with a radiation-sensitive catheter, optimized to sense charged particle rather than gamma or x-radiation, specific lesions could be identified and localized. Charged particle radiation is emitted as a byproduct of nearly all radioactive decay but is typically most abundant in radionuclides that decay by beta emission (either positrons or negatrons). Prototype catheters, using a plastic scintillator mated to an optical fiber, have been tested in the laboratory with the positron-emitting radiopharmaceutical 18FDG. The catheter had sufficient sensitivity to detect lesions concentrating nanocurie concentrations of 18FDG. Ex vivo experiments in apo-e-/- mice confirmed the ability of the catheter to detect 18FDG in aortic lesions. These feasibility studies demonstrate the sensitivity of a beta-sensitive catheter system. Additional mechanical refinements are needed to optimize the system in anticipation of in vivo animal studies.

Animals↗
PubMed2005

Real-time prognosis for metastatic thyroid carcinoma based on 2-[18F]fluoro-2-deoxy-D-glucose-positron emission tomography scanning.

CONTEXT/OBJECTIVE: Approximately 15% of thyroid cancer patients develop subsequent metastases. The clinical course of patients with metastatic thyroid carcinoma is highly variable. We hypothesized that the metabolic activity of metastatic lesions, as defined by retention of 2-[(18)F]fluoro-2-deoxyglucose (FDG), would correlate with prognosis. DESIGN/PATIENTS: The initial FDG-positron emission tomography (PET) scans from 400 thyroid cancer patients were retrospectively reviewed and compared with overall survival (median follow-up, 7.9 yr). We examined the prognostic value of clinical information such as gender, age, serum thyroglobulin, American Joint Committee on Cancer (AJCC) stage, histology, radioiodine avidity, FDG-PET positivity, number of FDG-avid lesions, and the glycolytic rate of the most active lesion. RESULTS: Age, initial stage, histology, thyroglobulin, radioiodine uptake, and PET outcomes all correlated with survival by univariate analysis. However, only age and PET results continued to be strong predictors of survival under multivariate analysis. The initial American Joint Committee on Cancer stage was not a significant predictor of survival by multivariate analysis. There were significant inverse relationships between survival and both the glycolytic rate of the most active lesion and the number of FDG-avid lesions. CONCLUSIONS: FDG-PET scanning is a simple, expensive, but powerful means to restage thyroid cancer patients who develop subsequent metastases, assigning them to groups that are either at low (FDG negative) or high (FDG positive) risk of cancer-associated mortality. We propose that the aggressiveness of therapy for metastases should match the FDG-PET status.

Adult↗
PubMed2005

The role of 99mTc-tetrofosmin scintigraphy for staging patients with laryngeal cancer.

Diagnosis and staging of laryngeal cancer is currently based on physical examination, endoscopy, and imaging techniques such as computed tomography (CT) and/or magnetic resonance (MR) and histology. While imaging techniques have a pivotal role for defining the size of the primary tumor, they are less accurate for defining metastatic involvement of regional lymph nodes, especially if lymph nodes are smaller than 10-15 mm. The aim of this study was to comparatively assess the relevance of (99m)Tc-tetrofosmin scintigraphy for the staging of laryngeal tumors versus the CT scan. We evaluated the sensitivity of imaging with (99m)Tc-tetrofosmin in 28 consecutively enrolled patients with squamous cell laryngeal carcinoma. Total-body scintigraphy with 99mTc-tetrofosmin was performed preoperatively, and the results were compared to CT images of the neck and mediastinum. CT and (99m)Tc-tetrofosmin scintigraphy were equally sensitive (96%) in identifying the primary tumor. While CT was more sensitive for detecting metastatic lymph nodes (100% versus 50%), (99m)Tc-tetrofosmin scintigraphy was more specific (100% versus 56%; p < 0.04). The overall diagnostic capabilities of the two techniques for detecting lymph node metastases were comparable (Youden Index: J = 0.56 for CT and J = 0.50 for (99m)Tc-tetrofosmin scintigraphy). (99m)Tc-tetrofosmin scintigraphy is a useful complement to CT for staging laryngeal tumors, especially for detecting metastatic lymph nodes and distant metastases.

Aged↗
PubMed2005

An analysis of the 18F-FDG uptake pattern in the stomach.

UNLABELLED: The concentration of (18)F-FDG in the gastroesophageal junction (GEJ) and gastric antrum (GA) varies significantly from patient to patient. To document the reference range of uptake in patients, we reviewed the (18)F-FDG PET scans of patients with no documented gastroesophageal disease. METHODS: The medical records of patients undergoing PET/CT were reviewed. Patients with known gastric, pancreatic, or liver pathology were excluded. The peak standardized uptake value (SUV) for the GEJ and GA were measured in the remaining patients. The clinical record was also reviewed for gastroesophageal reflux disease (GERD) and previous chemotherapy. RESULTS: A total of 763 patients met the inclusion criteria (388 male and 375 female; mean age +/- SD, 57.4 +/- 17 y; range, 15-95 y). Images were recorded 68.2 +/- 11.8 min after injection of 558.7 +/- 35.1 MBq of (18)F-FDG. PET/CT was performed on a Discovery LS scanner for 373 patients and on a Biograph scanner for 390. The maximum SUV was less than 4 in 94.4% of patients. GEJ SUV measurements on the Discovery LS and on the Biograph did not significantly differ. During the 6 mo before the scan, 515 patients received no antineoplastic chemotherapy. Of the remaining 248, 137 received chemotherapy within 1 mo before the scan; 65, between 1 and 3 mo before the scan; and 46, between 3 and 6 mo before the scan. No significant differences were found between groups. GERD was documented in the records of 75 patients. Only 58 of these patients were treated with an antacid regimen. In 552 patients, GERD was not known to be present nor was antacid treatment used. An additional 136 patients had antacid treatment without specified gastric symptomatology. Patients with a history of GERD had a slightly higher but not statistically significant SUV peak in the stomach and particularly in the GEJ, except when compared with the group without associated antacid treatment (P = 0.049). CONCLUSION: In patients without a specific history of esophagogastric disease, a gastroesophageal maximum SUV less than 4 is usually not associated with gastroesophageal neoplasia.

Adolescent↗
PubMed2005

Enhanced apoptotic reaction correlates with suppressed tumor glucose utilization after cytotoxic chemotherapy: use of 99mTc-Annexin V, 18F-FDG, and histologic evaluation.

UNLABELLED: Cancer chemotherapy enhances the apoptosis, whereas apoptosis is a suicidal mechanism requiring energy. We determined the relationship between apoptosis and glucose utilization during cancer chemotherapy using (99m)Tc-annexin V ((99m)Tc-annexin A5) and (18)F-FDG and compared their uptake with histologic findings in a rat tumor model. METHODS: Allogenic hepatoma cells (KDH-8) were inoculated into the left calf muscle of male Wistar rats (WKA). Eleven days after the inoculation, the rats were randomly divided into 3 groups: The first group (n = 7) received a single dose of gemcitabine (90 mg/kg, intravenously), the second group (n = 8) received cyclophosphamide (150 mg/kg, intraperitoneally), and the third group (n = 7) was untreated and served as the control group. We injected (99m)Tc-annexin V 48 h after the chemotherapy and then injected (18)F-FDG to all rats 1 h before sacrifice. Six hours after (99m)Tc-annexin V injection, the rats were sacrificed and the organs, including the tumor, were removed and radioactivity was counted. The radioactivities of (18)F and (99m)Tc in the organs were determined using normalization by tissue weight. Histologic evaluation by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) method and the immunostaining of glucose transporter-1 (GLUT-1) were also performed to obtain the indices of apoptosis and glucose utilization, respectively. The rate of positively stained cells was calculated and analyzed statistically. RESULTS: After chemotherapy using gemcitabine and cyclophosphamide, the (99m)Tc-annexin V uptake (percentage injected dose per gram x kg [(%ID/g) x kg]; mean +/- SD) in tumor increased significantly (0.062 +/- 0.012 (%ID/g) x kg in the gemcitabine-treated group and 0.050 +/- 0.012 (%ID/g) x kg in the cyclophosphamide group vs. 0.031 +/- 0.005 (%ID/g) x kg in the control group; P < 0.01). In contrast, the (18)F-FDG in tumor decreased significantly (0.483 +/- 0.118 (%ID/g) x kg in the gemcitabine group and 0.583 +/- 0.142 (%ID/g) x kg in the cyclophosphamide group) compared with that in the control group (0.743 +/- 0.084 (%ID/g) x kg; P < 0.01). In addition, (18)F-FDG uptake in tumor negatively correlated with (99m)Tc-annexin V uptake (r = -0.75; P < 0.01). In the gemcitabine and cyclophosphamide groups, the rate of TUNEL positively stained cells was significantly higher than that in the control group (10.2% +/- 1.7% and 8.0% +/- 1.5% vs. 5.2% +/- 1.5%; P < 0.01), whereas the GLUT-1 expression level showed no definite changes in histologic analyses. CONCLUSION: These data indicate that an enhanced apoptotic reaction correlated with suppressed tumor glucose utilization after cytotoxic chemotherapy as determined using radiotracers and histologic evaluation. The increase in (99m)Tc-annexin V and the decrease in (18)F-FDG in tumor can be useful markers for predicting therapeutic outcomes and for prognosis at the early stage of chemotherapy.

Animals↗
PubMed2005

Association of vascular 18F-FDG uptake with vascular calcification.

UNLABELLED: Both calcification and FDG uptake have been advocated as indicators of atheroma. Atheromas calcify as cells in the lesion undergo apoptosis and necrosis during evolution of the lesion and at the end stage of the lesion. FDG concentrates in lesions due to the relatively dense cellularity in regions of inflammation of active atheromas. This investigation examines the geographic relationship of focal vascular (18)F-FDG uptake, as a marker of atherosclerotic inflammation, to arterial calcification detected by contemporaneous CT. METHODS: We reviewed PET/CT images from 78 patients who were referred for tumor staging for the presence of vascular (18)F-FDG uptake and vascular calcification. Arterial wall (18)F-FDG accumulation greater than adjacent blood-pool activity was considered inflammation. Arterial attenuation of >130 Hounsfield units was considered calcification. Sites in the ascending and descending aorta, the carotid and iliac arteries, and the coronary territories were examined on the emission, CT, and fusion images on a point-by-point basis. When lesions were seen, we evaluated whether they were overlapping or discrete. RESULTS: The (18)F-FDG arterial distribution was consistent with established atherosclerotic topography, with increased uptake in the thoracic aorta, at the carotid bifurcation, and in the proximal coronary vessels. Arteries typically displayed a patchwork of normal vessel, focal inflammation, or calcification; inflammation and calcification overlapped in <2% of cases. Arterial inflammation preceded calcification, in terms of mean patient age. Coronary inflammation was more prevalent in patients with more cardiovascular risk factors. CONCLUSION: Vascular calcification and vascular metabolic activity rarely overlap, suggesting these findings represent different stages in the evolution of atheroma.

Adolescent↗
PubMed2004

Lymphoscintigraphic and intraoperative detection of the sentinel lymph node in breast cancer patients: the nuclear medicine perspective.

The concept of sentinel lymph node biopsy in breast cancer surgery relates to the fact that the tumor drains in a logical way via the lymphatic system, from the first to upper levels. Therefore, (1) the first lymph node met (the sentinel node) will most likely be the first one affected by metastasis, and (2) a negative sentinel node makes it highly unlikely that other nodes are affected. Sentinel lymph node biopsy would represent a significant advantage as a mini-invasive procedure, considering that, after operation, about 70% of patients are found to be free from metastatic disease, yet axillary node dissection can lead to significant morbidity. Although the pattern of lymphatic drainage from a breast cancer can be very variable, the mammary gland and the overlying skin can be considered as a biologic unit in which lymphatics tend to follow the vasculature. Considering that tumor lymphatics are disorganized and relatively ineffective, subdermal, and peritumoral injection of small aliquots of radiotracer is preferred to intratumoral administration. (99m)Tc-labeled colloids with most of the particles in the 100-200 nm size range would be ideal for radioguided sentinel node biopsy in breast cancer. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy, as images are used to direct the surgeon to the site of the node. The sentinel lymph node should have a significantly higher count than background. After removal of the sentinel node, the axilla must be re-examined to ensure all radioactive sites are identified and removed for analysis. The success rate of radioguidance in localizing the sentinel lymph node in breast cancer surgery is about 94-97% in Institutions where a high number of procedures are performed, approaching 99% when combined with the vital blue dye technique. At present, there is no definite evidence that a negative sentinel lymph node biopsy is invariably correlated with a negative axillary status, except perhaps for T(1a-b) breast cancers, with size < or =1 cm. Randomized clinical trials should elucidate the impact of avoiding axillary node dissection in patients with a negative sentinel lymph node on the long-term clinical outcome of patients.

Breast Neoplasms↗
PubMed2004

Radioguided sentinel lymph node biopsy in patients with malignant cutaneous melanoma: the nuclear medicine contribution.

As for other solid tumors, malignant cutaneous melanoma drains in a logical way through the lymphatic system, from the first to subsequent levels. Therefore, the first lymph node encountered (the sentinel node) will most likely be the first to be affected by metastasis, and a negative sentinel node makes it highly unlikely that other nodes in the same lymphatic basin are affected. Sentinel lymph node biopsy distinguishes patients without nodal metastases, who can avoid nodal basin dissection with its associated risk of lymphedema, and those with metastatic involvement who might benefit from additional therapy. This procedure represents a significant advantage as a minimally invasive procedure, considering that only an average 20% of melanoma patients with Breslow thickness between 1.5 and 4 mm harbour metastasis in their sentinel node(s) and are therefore candidates to elective lymph node dissection procedures. The cells that originate cutaneous melanomas are located between dermis and epidermis, a zone that drains to the inner lymphatic network in the reticular dermis, in turn to larger collecting lymphatics in subcutis. Therefore, the optimal modality of interstitial administration of radiocolloids for lymphoscintigraphy and subsequent radioguided sentinel lymph node biopsy is through intradermal/subdermal injection. (99m)Tc-labeled colloids in various size ranges are equally adequate for radioguided sentinel lymph node biopsy in patients with cutaneous melanoma, depending on local experience and availability. For melanomas located in the midline area of the head, neck, and trunk, particular consideration should be given to ambiguous lymphatic drainage, which frequently requires interstitial administration virtually all around the tumor or surgical scar from prior excision of the melanoma. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy because images are used to direct the surgeon to the sites of the node(s). The sentinel lymph node should have a significantly higher count than that of background (at least 10:1 intraoperatively). After removal of the sentinel node, the surgical bed must be reexamined to ensure that all radioactive sites are identified and removed for analysis. The success rate of radioguidance in localizing the sentinel lymph node in melanoma patients is about 98% in institutions where a high number of procedures are performed, approaching 99% when combined with the vital blue dye technique. The procedure is becoming the standard of care for patients with cutaneous melanoma because of its high prognostic value that has led to include the procedure in the most recent version of the TNM staging system.

Gamma Cameras↗
PubMed2004

Molecular imaging in nuclear cardiology.

State-of-the-art techniques have been used to measure key aspects of cardiovascular pathophysiology from the birth of radionuclide cardiovascular imaging. However, during the last 30 years, there have been few innovative imaging advances to further our understanding of the complex physiologic processes. Molecular imaging now offers an array of tools to develop advanced diagnostic approaches and therapies for patients with coronary artery disease and heart failure. For example, the enhanced understanding of the pathophysiology of atheroma makes it possible to identify vulnerable plaque based on its metabolic signature or the presence of excessive apoptosis. Because the metabolic and apoptotic signals are large, it is likely that even small lesions will be visible. Of the many approaches that are being developed, 2 tracers appear most likely to be tested in the near future: (1) [18F]-fluorodeoxyglucose, to determine macrophage metabolism; and (2) radiolabeled annexin, to measure apoptosis of the inflammatory cells. Using existing techniques such as perfusion imaging, appropriate patients can be selected for treatment with novel therapies, such as stem cell transplantation or vascular gene therapy. Using positron tomography in place of single photon imaging adds the capability for the measurement of absolute perfusion and perfusion reserve to the information on regional perfusion. Flow reserve detects global decreases in perfusion and refines the determination of lesion severity available from perfusion imaging.

Annexins↗
PubMed2004

Feasibility of 99mTc-annexin V for repetitive detection of apoptotic tumor response to chemotherapy: an experimental study using a rat tumor model.

UNLABELLED: Annexin V (annexin A5), a human protein with a high affinity for phosphatidylserine, labeled with (99m)Tc can detect apoptosis in vivo. In the repetitive detection of apoptosis with (99m)Tc-annexin V, however, the specific binding of annexin V to phosphatidylserine might affect the subsequent detection of apoptosis with this compound. To determine whether there is interference with repetitive doses of annexin V, we evaluated the effects of previous administration of cold annexin V on accumulation of (99m)Tc-annexin V in tumors in an experimental tumor model. METHODS: Rats bearing hepatoma received cyclophosphamide (150 mg/kg, intraperitoneally) 11 d after the tumor inoculation. Cold annexin V (20 microg/kg, intravenously) was administered 24 h before or after the cyclophosphamide treatment (n = 7/group). (99m)Tc-Annexin V was injected intravenously (radioactive dose, 5-23 MBq/kg; mass dose, 20 microg/kg), and radioactivity in tissues was determined 6 h later. RESULTS: Accumulation of (99m)Tc-annexin V in tumors was not significantly affected by previous treatment with cold annexin V before or after chemotherapy. CONCLUSION: These results demonstrate the feasibility of (99m)Tc-annexin V imaging for repetitive detection of apoptosis, which is highly required in the clinical setting.

Animals↗
PubMed2004

Radionuclide gastroesophageal motor studies.

Disorders of the upper digestive tract have a high impact on modern society, in terms of both direct and indirect health care costs and of social burden. The most common presenting symptom is either dysphagia or dyspepsia. Discriminating specific diagnoses within this wide group of diseases requires sound clinical judgment and application of procedures to distinguish organic from nonorganic disease and to further characterize the functional or motility disturbance of nonorganic diseases. Non-radionuclide-based diagnostic techniques include both noninvasive tests (upper gastrointestinal barium series, ultrasonography, and breath test for gastric emptying) and invasive procedures (fiberoptic endoscopy, esophagogastroduodenoscopy, pharyngeal manometry, stationary esophageal manometry, 24-h pH monitoring, esophageal biliary reflux monitoring, multichannel intraluminal impedance, and electrogastrography). Some of these techniques are not well tolerated by patients or not widely available. Radionuclide transit/emptying scintigraphy provides a means of characterizing exquisite functional abnormalities with a set of low-cost procedures that are easy to perform and widely available, entail a low radiation burden, closely reflect the physiology of the tract under evaluation, are well tolerated and require minimum cooperation by patients, and provide quantitative data for better intersubject comparison and for monitoring response to therapy. Despite the relatively low degree of standardization both in the scintigraphic technique per se and in image processing, these methods have shown excellent diagnostic performance in several function or motility disorders of the upper digestive tract. Dynamic scintigraphy with a radioactive liquid or semisolid bolus provides important information on both the oropharyngeal and the esophageal phases of swallowing, thus representing a useful complement or even a valid alternative to conventional invasive tests (such as stationary esophageal manometry) for evaluating abnormalities of oropharyngoesophageal transit. Clinical applications of esophageal transit scintigraphy include disorders such as nutcracker esophagus, esophageal spasm, noncardiac chest pain of presumed esophageal origin, achalasia, esophageal involvement of scleroderma, and gastroesophageal reflux and monitoring of response to therapy (either medical or surgical treatment of disease-for example, organic disease such as esophageal cancer). Scintigraphy with a radiolabeled test meal represents the gold standard for evaluating gastric emptying, whereas more recent radionuclide methods include dynamic antral scintigraphy and gastric SPECT for assessing gastric accommodation. Clinical applications of gastric-emptying scintigraphy include, among others, evaluation of patients with dyspepsia and evaluation of gastric function in various systemic diseases affecting gastric emptying. The present review includes the proposal of clinical algorithms for evaluating patients with the main disorders of the upper digestive tract. These algorithms, originally derived from available literature, have been developed on the basis of a vast clinical experience in conjunction with the specialists more deeply involved in the care of patients with such disorders (medical and surgical gastroenterologists and nuclear medicine physicians). The role of radionuclide gastroesophageal motor studies is clearly identified in the various steps of patients' management, from the initial diagnostic approach to functional characterization to postoperative follow-up or monitoring of medical therapy.

Animals↗
PubMed2004

Detection of cardiomyocyte death in a rat model of ischemia and reperfusion using 99mTc-labeled annexin V.

UNLABELLED: There is increasing evidence that cell death after myocardial ischemia and reperfusion may begin as apoptosis rather than necrosis. To determine the time course, location, and extent of this process, we studied groups of rats after a 20-min interval of coronary occlusion and reperfusion. METHODS: After thoracotomy, the left coronary artery was occluded for 20 min. After release and before study, groups of animals were allowed to recover for various intervals: 0.5 h (n = 6), 1.5 h (n = 7), 6 h (n = 7), 1 d (n = 8), 3 d (n = 8), or 2 wk (n = 5). At the time of study, the rats were injected with 99mTc-annexin V (80-150 MBq). One hour later, to verify the area at risk, 201Tl (0.74 MBq) was injected intravenously just after the left coronary artery reocclusion and the rats were sacrificed 1 min later. Dual-tracer autoradiography was performed to assess 99mTc-annexin V uptake and the area at risk. RESULTS: Extensive 99mTc-annexin V uptake was observed in the mid myocardium after 0.5-1.5 h of reperfusion. The area of annexin uptake had expanded in the subendocardial and subepicardial layers at 6 h after reperfusion and then gradually lessened over 3 d. At 0.5 and 1.5 h of reperfusion, 99mTc-annexin V uptake ratios were 7.36 +/- 2.95 and 6.34 +/- 2.24 (mean +/- SD), respectively. The uptake ratios gradually decreased at 6 h, 1 d, 3 d, and 2 wk after reperfusion (4.65 +/- 1.93, 3.27 +/- 0.92 [P < 0.01 vs. 0.5 h], 1.84 +/- 0.55 [P < 0.001 vs. 0.5 h, P < 0.005 vs. 1.5 h], and 1.65 +/- 0.31 [P < 0.001 vs. 0.5 h, P < 0.005 vs. 1.5 h], respectively). CONCLUSION: These data indicate that annexin binding commences soon after ischemia and reperfusion in the mid myocardium within the area at risk and expands to include the subendocardial and subepicardial layers at 6 h after reperfusion, followed by gradual reduction of activity over 3 d.

Animals↗