The efficacy of cardiovascular nuclear medicine exercise studies

Radionuclide stress tests were initially introduced into medicine as new diagnostic tests for coronary artery disease (CAD). These tests are very effective for this purpose when applied to populations with an intermediate pre-test probability of coronary artery disease. Radionuclide stress tests, however, also are used now in guiding many management decisions in patients with established CAD, based on the ability of these tests to assess the extent and severity of myocardial ischemia, the functional significance of coronary stenoses, and myocardial viability. Specific uses beyond diagnosis include decisions regarding whom to catheterize, send to coronary bypass surgery, or angioplasty; risk stratification following myocardial infarction or before noncardiac surgery; and evaluation of the results of therapy. This article reviews both the diagnostic efficacy of radionuclide stress tests and their efficacy in guiding management decisions in patients with known coronary artery disease.     

细胞粘附分子的电离辐射效应研究进展

细胞粘附分子是调节细胞间及细胞与细胞外基质相互作用的一类膜型或跨膜糖蛋白,其作用涉及细胞的粘附、迁移、分化和信号转导。正常组织或肿瘤组织受电离辐射后会导致细胞粘附分子表达的改变。照射方式不同,受照组织不同,粘附分子的表达也不同,有些粘附分子的表达与受照剂量存在良好的量效关系。受照后,粘附分子的改变具有作为一种新的辐射生物剂量仪的潜能。     

Ultrasound in sports medicine

The accuracy of sonography in evaluating various conditions of the musculoskeletal system has been demonstrated and its utility as a primary diagnostic imaging modality in the musculoskeletal system in the United States has been increasing in frequency. Sonography is universally tolerated across a broad patient population, including pediatric and pregnant patients and those in whom traditional magnetic resonance (MR) imaging is not an option, due either to absolute or relative contraindications. Sonographic examinations are relatively quick compared with an MR or computed tomographic study, and delays in scheduling are therefore minimal, an advantage for those patients who have traveled a long distance or who are in a considerable amount of discomfort at the time of their visit to the orthopedic surgeon. With portable ultrasound units, examinations can be performed on the playing field, immediately at the time of the acute injury, for rapid diagnosis. Lastly, ultrasound can be used to guide for therapeutic procedures at the same time the diagnostic exam is performed.     

Clinical magnetic resonance imaging with nuclear medicine correlation

The current role of magnetic resonance imaging (MRI) in different organ systems is discussed and compared to nuclear medicine and to other available clinical diagnostic modalities. The value of optimizing radiofrequency pulse sequence selection to provide additional tissue characterization is also described. The results of nuclear medicine and MRI studies in 56 patients are compared to evaluate the clinical diagnostic contribution of each imaging modality for various pathological processes. In addition, the state-of-the-art MRI systems and future development in MRI technology with its potential contribution is defined.     

Planning transarterial radioembolization of colorectal liver metastases with Yttrium 90 microspheres: evaluation of a sequential diagnostic approach using radiologic and nuclear medicine imaging techniques

The purpose of the study was to establish a diagnostic approach to the preparation of patients with colorectal liver metastases considered for transarterial radioembolization (RE). Twenty-two patients sequentially underwent computed tomography (CT; thorax/abdomen), magnetic resonance imaging (MRI; liver; hepatocyte-specific contrast), positron emission tomography (PET/PET-CT; F18-fluoro-desoxy-glucose), and angiography with perfusion scintigraphy [planar imaging; tomography with integrated CT (SPECT-CT)]. The algorithm was continued when no contraindication or alternative treatment option was found. The impact of each test on the therapy decision and RE management was recorded. Patient evaluation using CT revealed contraindications for RE in 4/22 patients (18%). Of the remaining 18 patients, 2 were excluded and 3 were assigned to locally ablative treatment based on MRI and PET results (28%). The remaining 13 patients entered the planning algorithm: SPECT-CT revealed gastrointestinal tracer accumulations in 4 (31%) patients [SPECT, 2 (15%)], making a modified application necessary. In five patients (38%), planar scintigraphy revealed relevant hepatopulmonary shunting. Therapy was finally administered to all 13 patients without therapy-related pulmonary or gastrointestinal morbidity. Each part of the diagnostic algorithm showed a relevant impact on patient management. The sequential approach appears to be suitable and keeps the number of unnecessary treatments and therapy risks to a minimum.     

Nuclear medicine imaging in tuberculosis using commercially available radiopharmaceuticals

In this paper, data available on nuclear medicine imaging using commercially available radiopharmaceuticals for the differentiation, staging, and prediction or assessment of the response to treatment in tuberculosis (TB) are reviewed. Limited available studies suggest that single photon emission computed tomography (SPECT) using either 201Tl, 99mTc-sestamibi, or 99mTc-tetrofosmin is accurate (≥85%) and has a high negative predictive value (≥90%) for the differentiation of TB from carcinoma in patients presenting with a solitary pulmonary nodule (SPN). The criteria for detection of TB on 201Tl SPECT are nondepiction of the suspicious lesion in the delayed image or a negative retention index [washout on the delayed images (3–4 h postinjection) vs. the early image (5–15 min postinjection)] and a comparable-to-background uptake on 99mTc-sestamibi or 99mTc-tetrofosmin SPECT. Another SPECT tracer of potential interest for the differentiation of TB from malignant SPN that warrants further exploration, is N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). In contrast, 18F-fluorodeoxyglucose (18F-FDG) PET is unable to differentiate malignancy from TB and thus cannot be used as a tool to reduce futile biopsy/thoracotomy in these patients. A limited number of studies have reported on the potential of nuclear medicine imaging in assessment of the extent of disease in patients with extrapulmonary TB using 67Ga-citrate SPECT and 18F-FDG PET, respectively. 67Ga-citrate SPECT was shown to be as sensitive as bone scintigraphy for the detection of bone infection and was found to be complementary to computed tomography (CT) imaging. 18F-FDG PET was found to be significantly more efficient when compared with CT, respectively, in over half of patients for the identification of sites of lymph node involvement that were missed by CT and often the only sites of extrapulmonary TB identified. Unfortunately, 18F-FDG PET findings did not lead to alterations in treatment planning in any of the patients under study. Additional studies confirming these findings are urgently required. Similar to the setting of SPN, 18F-FDG PET cannot differentiate malignant lymph node involvement from lymph node involvement by TB. These results and the recent findings of Demura and colleagues using 18F-FDG PET further suggest that nuclear medicine imaging techniques could be used for the evaluation of therapeutic response. Prospective studies, focusing on specific subgroups of patients in whom such an imaging approach might be clinically relevant, for example in multidrug-resistant TB patients, are warranted. In acquired immunodeficiency syndrome patients, 67Ga scintigraphy proved to be a reliable and sensitive method for the primary detection and follow-up of opportunistic pneumonias, including TB. Combining 201Tl scintigraphy with 67Ga scintigraphy was shown to increase the specificity for both pulmonary and extrapulmonary TB, which is a 67Ga(+) and 201Tl(-) mismatch pattern in acquired immunodeficiency syndrome patients that is specific for mycobacterial infections. Finally, the results obtained using both SPECT and PET indicate that nuclear medicine could be an important noninvasive method for the determination of disease activity, detection of extrapulmonary TB, and determination of response to therapy.     

Nuclear medicine studies in evaluation of skeletal lesions in children with histiocytosis X

Radiographs were compared with 99mTc scans of the bones and bone marrow as well as 67Ga-citrate scans to evaluate their sensitivity in identifying skeletal lesions in 21 children with histiocytosis X. Seven of 20 bone scans were completely normal in patients with extensive radiographic evidence of skeletal disease. In only one patient were bone scan changes demonstrated prior to radiographic abnormalities. None of the lesions was "cold" on the bone scans. 99mTc-sulfur colloid bone marrow scans and 67Ga-citrate whole-body scans were not valuable. Radiographic survey of the skeleton should be the primary diagnostic test employed in patients with histiocytosis X who have suspected skeletal lesions. Bone scans should be obtained only when the radiographs are normal or equivocal.     

Exposure of critical groups to nuclear medicine patients

When a radiopharmaceutical has been administered to a patient, assessment of the risk to critical groups from emitted photon radiation is by measurement of the integral dose received by an individual, or by measurements of the dose rate external to the patient coupled with appropriate occupancy factors. Estimations have been made from the available data of the dose to critical groups exposed to patients who have undergone diagnostic or therapeutic procedures. These dose estimations can be used to assess the impact of the proposed changes in statutory requirements, and to allow appropriate recommendations to be formulated. Two areas for consideration are that pregnant staff exposed to nuclear medicine patients will require an abdominal surface dose limit lower than 2 mSv to restrict their foetal dose to 1 mSv, and the current UK restrictions for the behaviour of patients who have undergone ¹³¹I treatment are either already adequate or can even be relaxed in order to restrict the exposure of members of the public to the proposed lower dose limits. Agreement is needed on the value (e.g. 95th percentile) from a study of the dose to a number of individuals which should serve as the basis for radiation protection recommendations.     

Computed tomography in cervical spondylotic myelopathy and radiculopathy: visualisation of structures,myelographic comparison,cord measurements and clinical utility

Summary Sixty-nine patients with cervical spondylotic myelopathy (CSM), radiculopathy (CSR), or both (CSMR) were studied with computed tomography (CT). Computer-assisted myelography (CAM) accurately determines the site and nature of spondylotic protrusions and provides good visualisation of the subarachnoid space and cord deformities even in areas with dilute metrizamide. However, excessive vertebral movement and bulging ligamenta flava with their effects on cord deformity, so easily visualised in myelograms, are completely or partially missed. In the assessment of CSM, metrizamide myelography (MM) followed by CAM should be performed, particularly when the myelographic images are unsatisfactory due to contrast dilution or blockage, when cord compression cannot be ascertained with MM and when cord atrophy is suspected. In CSR, the diagnostic information from MM and CAM is comparable. The diagnostic criteria in CAM are, however, less direct and since MM is adequate in uncomplicated cases, CAM is generally not necessary. The APD, APD/TD ratio, area and circularity are sensitive indices of cord deformity and the first two should be used more often to assist visual assessment of cord deformity. The relation between cord parameters and treatment response is better reflected in CSM cases managed conservatively and the results suggest that the degree of cord deformity is helpful in determining the outcome and hence the choice between surgical and conservative treatment. In plain CT, the osteophytes and calcified discs are adequately visualised and canal dimensions measured with accuracy, but the cervical cord and roots cannot be properly assessed and the diagnosis of CSM or CSR cannot be ascertained. At present, its role in cervical spondylosis is therefore limited.     

Nuclear medicine in diagnosis and therapy of bone and joint diseases

Concerning bone and joint diseases therapy of rheumatic synovitis (= radiosynoviorthesis) was introduced in 1952 before clinically relevant diagnostic procedures were developed. Radionuclides of Sr and later on 99mTc phosphonates then started the wide use of bone scintigraphy since > 30 years. The diagnostic methods have an excellent sensitivity for detection of local abnormalities of bone metabolism, the specificity of such studies, however, is low. Modifications of the technique (3-phase-bone-scintigraphy, pinhole collimators, ROI-technique), increasing knowledge of pathological scan patterns and introduction of other radionuclide studies (67Ga, 201Tl, inflammation scans with 99mTc-leukocytes or 99mTc-HIG) as well as 18FDG-PET have increased the specificity significantly in recent years and improvements of imaging systems (SPECT) also increased the accuracy of diagnostic methods in diseases of bone and joints. Therapy of such diseases has made considerable progress: inflamed, swollen joints can effectively be treated with 90Y-, 186Re, 169Er-colloids or with 165Dy-particles by radiosynoviorthesis. Severe pain due to disseminated bone metastases of cancer or polyarthritis can be controlled by radionuclide therapy with 89Sr, 153Sm-EDTMP, 186Re- or 188Re-HEDP and possibly 117mSn-DTPA with an acceptable risk of myelodepression. Possibilities, technical details and limitations of radionuclide applications for diagnostic and therapeutic purposes must be considered if optimal benefit for individual patients should be achieved. Overall Nuclear Medicine can become an essential element in management of bone and joint diseases. The relationship of Nuclear Medicine to bone and joint pathology is peculiar: In 1952 treatment of rheumatic synovitis by radiosynoviorthesis with 198Au Colloid was started by Fellinger and Schmid before diagnostic approaches to bone pathology existed. Bone scintigraphy was introduced only in 1961 using 85Sr but obviously the unfavourable radiation characteristics of this radionuclide limited it's broad application and 87mSr did not improve this situation. Only when 99mTc phosphonates were developed by Subramanian the importance of bone scintigraphy became apparent: The excellent imaging properties of these radiotracers showed, that abnormal bone metabolism could be visualized even before morphological alterations in the skeleton become visible on radiographies or even CT-scans. Moreover, proposals made earlier to use 32P or 89Sr for palliation of pain in patients with disseminated skeletal metastases were picked up again and led also to other radiopharmaceuticals (186Re-HEDP, 153Sm-EDTMP, 117mSn-DTPA) which are applied today for the same purpose with very good success. Therefore Nuclear Medicine today has a broad program for diagnostic and therapeutic approaches to diseases of bone and joints. In bone scanning the high sensitivity led to inclusion of this method for routine staging and re-staging programs in a variety of cancer forms which have a trend to develop bone metastases (e.g. breast, lung, prostate, melanoma) but the low specificity of abnormal patterns on such scans can impair the diagnostic value of the technique. To increase specificity and to define inflammatory lesions, radiotracers used for "inflammation scanning" were introduced such as labeled granulocytes, 99mTc Human Immunoglobulin and others but also a simple modification of bone scanning--triple phase bone scintigraphy--was used. Recently the excellent properties of 18F for PET of the skeleton were rediscovered again and emission CT scanning--possibly with overlay with transmission CT or MRT pictures--can enhance the diagnostic impact of radionuclide bone studies.     

The effect of pelvic MR imaging on the diagnosis and treatment of women with presumed symptomatic uterine fibroids

PURPOSE: To determine if magnetic resonance (MR) imaging significantly alters the diagnostic thinking and treatment plans of interventional radiologists during the evaluation of women for uterine fibroid embolization (UFE) for presumed uterine fibroids. MATERIALS AND METHODS: At a single institution, interventional radiologists prospectively completed questionnaires (n = 60) before and after MR imaging was performed in their evaluation of women presenting for potential UFE. The questionnaires asked these physicians the probability (0%-100%) of their most likely diagnosis before MR imaging and after receiving the MR imaging information. They were also asked their anticipated and final treatment plans. Diagnostic confidence gains and the proportion of patients with changed initial diagnoses or anticipated management were calculated. The Wilcoxon signed-rank test was used to assess gains in diagnostic confidence. RESULTS: MR imaging caused a mean gain in diagnostic confidence of 22% (P <.0001). MR imaging changed initial diagnoses in 11 patients (18%). Immediate clinical management changed in 13 patients (22%). UFE was not performed in 11 of 57 women (19%) who were anticipated before MR imaging to receive UFE. CONCLUSIONS: MR imaging significantly alters the diagnoses and treatment plans of interventional radiologists evaluating women with presumed symptomatic fibroids. MR imaging should be considered in all patients before UFE.     

Nuclear medicine studies in metabolic bone disease

The principal application of nuclear medicine in metabolic bone disease is the isotope bone scan. Often, it is not a diagnostic tool but can be useful in clarifying the nature of a clinical problem. The best-established role for the bone scan in metabolic bone disease is in Paget's disease, in which it is diagnostic, provides definition of the extent of disease, and probably reflects disease activity. The isotope bone scan is also important in osteoporosis, for which it is not diagnostic but may often provide useful information to confirm that fracture has occurred, determine the age of the fracture, identify unsuspected fractures, and identify other causes for pain, for example, facet joint disease. The bone scan is less useful in other metabolic bone diseases, for example, renal osteodystrophy and osteomalacia, but will often have a characteristic appearance, with several metabolic features. The degree of positivity of the scan generally relates to the severity of the hyperparathyroidism. In patients with metabolic bone disease, other specific clinical problems may arise, such as osteomyelitis or avascular necrosis, and the bone scan may be diagnostic in these conditions. Nuclear medicine techniques are also of value in hyperparathyroidism and to localize the site of the adenoma where surgical treatment is being considered; the use of technetium Tc 99m sestamibi is now routine. More recently, positron emission tomography (PET) scanning has been found to be helpful in the more difficult cases.     

Three-phase radionuclide bone imaging in sports medicine

Three-phase radionuclide bone (TPB) imaging was performed on 238 patients with sports-related injuries. A wide variety of lesions was encountered, but the most frequent lesions seen were stress fractures of the lower part of the leg at the junction of the middle and distal thirds of the posterior tibial cortex (42 of 79 lesions). There were no differences in the type, location, or distribution of lesions between males and females or between competitive and noncompetitive athletes. In 110 cases, bone stress lesions were often diagnosed when radiographs were normal, whereas subacute or chronic soft-tissue abnormalities had few specific scintigraphic features. TPB imaging provides significant early diagnostic information about bone stress lesions. Normal examination results (53 cases) exclude underlying osseous pathologic conditions.     

Nuclear medicine imaging of bone infections

The inflammation and infection of bone include a wide range of processes that can result in a reduction of function or in the complete inability of patients. Apart from the inflammation, infection is sustained by pyogenic microorganisms and results mostly in massive destruction of bones and joints. The treatment of osteomyelitis requires long and expensive medical therapies and, sometimes, surgical resection for debridement of necrotic bone or to consolidate or substitute the compromised bones and joints. Radiographs and bone cultures are the mainstays for the diagnosis but often are useless in the diagnosis of activity or relapse of infection in the lengthy management of these patients. Imaging with radiopharmaceuticals, computed tomography and magnetic resonance are also used to study secondary and chronic infections and their diffusion to soft or deep tissues. The diagnosis is quite easy in acute osteomyelitis of long bones when the structure of bone is still intact. But most cases of osteomyelitis are subacute or chronic at the onset or become chronic during their evolution because of the frequent resistance to antibiotics. In chronic osteomyelitis the structure of bones is altered by fractures, surgical interventions and as a result of bone reabsorption produced by the infection. Metallic implants and prostheses produce artefacts both in computed tomography and magnetic resonance images, and radionuclide studies should be essential in these cases. Vertebral osteomyelitis is a specific entity that can be correctly diagnosed by computed tomography or magnetic resonance imaging at the onset of symptoms but only with radionuclide imaging is it possible to assess the activity of the disease after surgical stabilization or medical therapy. The lack of comparative studies showing the accuracy of each radiopharmaceutical for the study of bone infection does not allow the best nuclear medicine techniques to be chosen in an evidence-based manner. To this end we performed a meta-analysis of peer reviewed articles published between 1984 and 2004 describing the use of nuclear medicine imaging for the study of the most frequent causes of bone infections, including prosthetic joint, peripheric post-traumatic bone infections, vertebral and sternal infections. Guidelines for the choice of the optimal radiopharmaceuticals to be used in each clinical condition and for different aims is provided.     

Contributions of nuclear medicine to the therapy of malignant tumors

The diagnostic and therapeutic application of radionuclides in oncology has led to an increased efficiency in the treatment of malignant tumors. Regarding diagnosis, measuring metabolic reactions in tumor tissue, especially by positron emission tomography, opened the potential for assaying tumor response to different treatment modalities and thus eventually for tailoring effective treatment of a given tumor in the individual patient. Regarding treatment, attention is given to the choice of the radionuclide for optimal deposition of the desired radiation in tumor cells avoiding exposure of normal cells; in this context microdosimetric considerations are essential with respect to beta-emitters, alpha-emitters, the Auger-effect and neutron capture therapy. Examples of therapeutic uses of radionuclides in the inorganic form are 131-I for thyroid cancer and 32-P for polycythemia vera; organically bound radionuclides are employed with precursors for tumor cell metabolism or with receptor seeking agents, such as MIBG and monoclonal antibodies which presently enjoy a particular interest and bear great promise. Stable nuclides, if properly accumulated within tumors, may be activated for therapy in situ, for example by thermal neutrons, as in neutron capture therapy using the 10-B (n, alpha)7-Li reaction. Treatment planning and execution with radionuclides have gained momentum over the past decade, yet much more needs to be done.     

Artificial neural networks in nuclear medicine

An analysis of the accessible literature on the diagnostic applicability of artificial neural networks in coronary artery disease and pulmonary embolism appears to be comparative to the diagnosis of experienced doctors dealing with nuclear medicine. Differences in the employed models of artificial neural networks indicate a constant search for the most optimal parameters, which could guarantee the ultimate accuracy in neural network activity. The diagnostic potential within systems containing artificial neural networks proves this calculation tool to be an independent or/and an additional device for supporting a doctor's diagnosis of artery disease and pulmonary embolism.     

Fetus radiation doses from nuclear medicine and radiology diagnostic procedures. Potential risks and radiation protection instructions

Although in pregnancy it is strongly recommended to avoid diagnostic nuclear medicine and radiology procedures, in cases of clinical necessity or when pregnancy is not known to the physician, these diagnostic procedures are to be applied. In such cases, counseling based on accurate information and comprehensive discussion about the risks of radiation exposure to the fetus should follow. In this article, estimations of the absorbed radiation doses due to nuclear medicine and radiology diagnostic procedures during the pregnancy and their possible risk effects to the fetus are examined and then discussed. Stochastic and detrimental effects are evaluated with respect to other risk factors and related to the fetus absorbed radiation dose and to the post-conception age. The possible termination of a pregnancy, due to radiation exposure is discussed. Special radiation protection instructions are given for radiation exposures in cases of possible, confirmed or unknown pregnancies. It is concluded that nuclear medicine and radiology diagnostic procedures, if not repeated during the pregnancy, are rarely an indication for the termination of pregnancy, because the dose received by the fetus is expected to be less than 100 mSv, which indicates the threshold dose for having deterministic effects. Therefore, the risk for the fetus due to these diagnostic procedures is low. However, stochastic effects are still possible but will be minimized if the radiation absorbed dose to the fetus is kept as low as possible.     

Effect of MR angiography on the diagnosis and treatment of patients with suspected renovascular disease

PURPOSE: Although the diagnostic accuracy of renal magnetic resonance (MR) angiography is established, its effect on referring physicians is unknown. The authors prospectively measured the effect of MR angiography results on referring physicians' diagnosis and treatment (plans) of patients with suspected renovascular disease. MATERIALS AND METHODS: Referring physicians prospectively completed questionnaires before and after MR angiography was performed during evaluation of their patients with suspected renovascular disease. The questionnaires asked them to estimate the probability (0%-100%) of their most likely diagnosis before and after receiving the imaging information. They were also asked for their anticipated and final treatment plans. The authors calculated the mean gain in diagnostic percentage confidence and the proportion of patients with changed initial diagnoses or anticipated management. A paired t-test was used to assess significance of the gains in diagnostic percentage confidence. RESULTS: Physicians prospectively completed pre- and post-MR-angiography questionnaires for 30 patients. MR angiography improved mean diagnostic certainty by 35% (P < .0001). MR angiography changed physicians' initial diagnoses in 12 patients (40%). Anticipated treatment plans were changed in 20 patients (67%). Invasive procedures were avoided in eight patients (27%). CONCLUSION: MR angiography has a substantial effect on the diagnostic and therapeutic decision-making of physicians managing patients with suspected renovascular disease.     

A profile of patients attending sports medicine clinics

OBJECTIVES: To describe the sociodemographic profile of sports injury patients who attend sports medicine clinics for treatment and to describe their reasons for choosing to attend such clinics. METHOD: Data were collected as part of a fully audited injury surveillance system implemented within sports medicine clinics. The study was conducted within five allied multidisciplinary sports medicine clinics in metropolitan Melbourne, Australia. All patients initially presenting for treatment of a new sports or active recreation injury over the period August 1997 to August 1998 were eligible for this study, irrespective of the practitioner providing the treatment. Data were obtained on 6476 patients. RESULTS: The median age of the patients was 25.4 years (range 6.8--81.6) and most were male (69.8% of cases; 95% confidence interval (95% CI) 68.7 to 70.9). Patients had both professional and non-professional backgrounds and were not just local suburb residents. Many patients had insurance cover for their injury treatment: 59.0% (95% CI 58.6 to 59.4) had some private health insurance and 46.6% (95% CI 45.4 to 47.8) had club/association insurance. The most common reasons for attending a clinic was its location (36.8%; 95% CI 36.5 to 37.1) and referral/recommendation (31.0%; 95% CI 30.7 to 31.3). CONCLUSION: Sports medicine clinics provide treatment for a broad spectrum of injured sports participants across a variety of sporting/recreation contexts. Although these clinics mainly serve the immediate geographic community, the sports speciality and expertise of a particular clinic can attract patients from further afield. This information can help sports medicine clinics to market their services more efficiently to meet the needs of their potential patients.