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Biomedical subjects

M Salvatori

Publications and source records attributed to M Salvatori.

69 records · Page 4Linked to original sources

99mTc-human immunoglobulin (HIG) in AIDS patients: first results.

Scintigraphy with 99mTc labelled human polyclonal immunoglobulin was performed in 16 patients with ascertained or suspected AIDS-related infections. 99mTc-HIG lung scanning was compared, in 11 patients, with 67Ga scintigraphy, chest X-ray and high resolution lung CT. 67Ga and 99mTc-HIG were concordantly positive in five cases of BAL-ascertained Pneumocystis carinii pneumonia (PCP), while one of them was Rx and CT negative. X-ray, 67Ga and 99mTc were concordantly negative in 5 cases. 99mTc-HIG yielded negative results in two cases of Mycobacterium infection, both of which were 67Ga and Rx positive: Mycobacterium avium in diffuse lung involvement and Mycobacterium TBC in excavated infiltrate. 99mTc-HIG was also positive in other 3 AIDS patients: 1 case of intestinal cryptosporidiosis, 1 pulmonary abscess (Staphylococcus and Candida), and 1 sacral abscess; it was negative in 1 case of Kaposi sarcoma (also 201Tl negative). In conclusion, 99mTc-HIG scintigraphy in AIDS patients is feasible, and offers some practical advantages (continuous availability, fast response time, etc.). The initial results seem similar to those of 67Ga in lung scanning (and perhaps more specific for PCP).

Acquired Immunodeficiency Syndrome↗

[Scintigraphic diagnosis of Meckel's diverticulum using Tc-99m-pertechnetate].

Meckel's diverticulum (MD) is a well-known cause of lower gastrointestinal hemorrhage, particularly in the pediatric age group. The radionuclide 99mTc-pertechnetate has been found useful in visualizing MD which contain gastric mucosa. This test is predicated of the affinity of the isotope for the parietal cells of the gastric glands. In an attempt to evaluate the sensibility and specificity of pertechnetate, the clinical data and scintigrams of 27 patients with suspected MD were reviewed. The scintigram correctly identified MD before operation in 6 of 7 patients. The false negative study occurred in a MD without gastric mucosa.

Adolescent↗

[The diagnosis of lung inflammation in AIDS patients. The use of 99mTc-labelled human polyclonal immunoglobulins and a comparison with 67Ga citrate and high-resolution computed tomography].

Technetium-99m (99mTc) labelled polyclonal human immunoglobulin (HIG) is a new agent for the localization of active inflammatory diseases. The results obtained with HIG in 29 AIDS patients referred for suspected lung infections are reported (Table I). The patients also underwent Gallium-67 citrate scanning (GS), chest radiography (Rx), high-resolution thin-layer computed tomography (HRCT) and broncho-alveolar lavage (BAL). The study population was classified as follows: 12 patients (Table II) were studied before treatment for suspected Pneumocystis carinii pneumonia (PCP), 7 patients (Table III) had known PCP and were studied during medical therapy, and 10 patients (Table IV) had lung infections other than PCP. In all PCP patients studied before treatment, positive agreement was observed between HIG, Rx and HRCT findings. In 4 patients with final clinical diagnosis of no lung conditions, both nuclear and radiologic imaging were negative. 99mTc-HIG results in the PCP patients studied during therapy were consistent with clinical and radiologic improvement; there was disagreement with 67Ga findings in one case (no. 9). In lung infections other than PCP, HIG studies were often negative (always negative in mycobacteriosis), while they were positive in 3 pyogenic abscesses. In conclusion, as for PCP and abscesses, the results obtained with 99mTc-HIG are usually in agreement with GS findings, while HIG scans seem to be negative in mycobacterial infections. Moreover, HIG scintigraphy seems to be suitable for the evaluation of treatment results in PCP (this subject deserves further research). To assess respiratory impairment a semiquantitative index (ISQ) of 99mTc-HIG lung uptake is suggested, which showed a significant linear correlation with arterial pO2.

AIDS-Related Opportunistic Infections↗

Multidisciplinary approach to venous thromboembolism.

Venous thromboembolism shows a high incidence and a significant mortality. Even if valid methods are available, thromboembolism is underdiagnosed. There are a number of diagnostic difficulties. They concern the time of the diagnostic suspicion, the patient selection for the various procedures and their combination. These difficulties may be overcome by team work where specialists of different disciplines (surgeons, internists, experts in nuclear medicine, radiologists) integrate their competence to attain the established objectives. The integration results in "synergism", namely an added value greater than the sum of competences of the team components. Thus, an operational unit active 24 hours over 24 must be formed to diagnose and treat the largest number of cases of thromboembolism. To establish the clinical suspicion of thromboembolism is the first indispensable step for patient selection. Thromboembolism should be investigated in all patients with chest pain, dyspnea and tachypnea in the absence of preexisting cardiorespiratory disease. The team should evaluate the impact of signs and symptoms to establish a definitive clinical probability which can direct towards the suitable, least invasive imaging procedure. Perfusion scanning, when highly suggestive or normal, is conclusive. However in 70% of cases it is indeterminate. Thus it should be combined with other procedures and with the clinical assessment. In practice, many dubious cases remain unsolved. The team work represents an organizational response to this diagnostic and therapeutic inadequacy. The real change in strategy which has revolutionized the diagnosis of thromboembolism was the widespread use of color Doppler US in the diagnosis of deep vein thrombosis. Since pulmonary embolism as well as deep vein thrombosis are treated with the same therapy, it is adequate to document the thrombosis also in the absence of a definitive demonstration of embolism. The old-fashioned approach should be reversed and the investigation should be centered on the assessment of deep vein thrombosis: site, emboligenic potential, floating extremity and extension. The integration of the clinical assessment, scanning finding and color Doppler US lowers by about 20% the number of indeterminate cases and indicates the patients for whom pulmonary spiral CT or pulmonary angiography is required. In all patients with cardiorespiratory insufficiency still unsolved after the combination of noninvasive exams, pulmonary angiography or spiral CT is mandatory because of the high risk for death. The remaining ones can be followed with serial color Doppler US exams. The cost/benefit ratio shows that the noninvasive strategy is the least expensive, the least hazardous and the most effective. At present, effective therapies are available for thromboembolism. Standard heparin and low molecular weight heparin fractions, fibrinolytic agents, surgery and recently caval filters are playing a major role in secondary prophylaxis of pulmonary embolism. The therapeutic approach is conditioned by various factors: the features of thrombosis, the presence and entity of pulmonary embolism, the patient cardiorespiratory condition, possible contraindications for anticoagulant and fibrinolytic agents. The presence of such a number of variables makes the use of a therapeutic algorithm, difficult. In this phase, based on our experience we believe that the present solution lies in the activity of an operational team of experts who establish the treatment to be performed.

Cost-Benefit Analysis↗

Advances in pulmonary nuclear medicine.

Nuclear medicine plays a major role in the diagnosis of pulmonary embolism as well as in other lung diseases. Important innovations have concerned in recent years the equipment and radiopharmaceuticals. In ventilation studies the use of technegas, a monodisperse aerosol able to supply images of the same quality or even superior to gas images, is widespread in the clinical practice. Significant clinical results in the evaluation of acute thromboembolism have been achieved with antifibrin monoclonal antibodies and radioactive peptides specific for activated platelet receptors. Primary lung cancer and its metastases can now be visualized with tracers used for the study of myocardial perfusion (sestaMIBI, tetrofosmin) or labeled ocreotide, a molecule able to recognize lung tumors with somatostatin receptors. 99mTc-NR-LU-10 Fab immunoscintigraphy was shown to be very sensitive for tumors, while the major role of PET in the differential diagnosis of solitary pulmonary nodule, in the initial staging and in the response assessment to lung cancer therapy, is confirmed. SPECT is widespread in the clinical field with the use of 2-3 head gamma cameras and the possible combined imaging with CT or MRI. The use of PET with common gamma cameras with appropriate collimation systems or coincident recording without collimation is being studied. PET is used in the study of tumor metabolism as well as in the evaluation of intra-and extravascular lung water, regional blood flow and pulmonary vascular permeability. PET studies of vascular lung physiology as well as of receptor physiology, amine accumulation and clearance and drug transport to the areas of healthy or impaired lung, were also shown to be fundamental.

Humans↗