Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0034065 (pulmonary embolism)
 14,979 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 53 patients with possible pulmonary embolism, pulmonary abnormalities of 133Xe ventilation and 99Tcm albumin microsphere perfusion scintigraphy were compared with absence or presence of pulmonary emboli documented by concurrent pulmonary angiography. It was found that patients with combined scintigraphy considered as unlikely for pulmonary embolism (ventilation defect larger than perfusion defect) or indicative of pulmonary embolism (ventilation defect smaller than perfusion defect) provide high diagnostic specificity. Patients with equal ventilation-perfusion abnormalities (possible pulmonary embolism) require further evaluation by pulmonary angiography to ascertain diagnosis. Importantly, diagnostic accuracy, using ventilation-perfusion scintigraphy and the quantified method of evaluation delineated, is preserved in patients with severe congestive heart failure.
 ...
PMID:Lung ventilation-perfusion scintigraphy in pulmonary embolism. Diagnostic specificity compared to pulmonary angiography. 73 45

Regional lung ischemia was imaged with a rapidly diffusible radioaerosol of pertechnetate. The method is compared with similar techniques using 11C and 15O. The principles involved include (A) the rapid alveolar-capillary diffusion of inhaled radioactive gases (11CO, C15O, and C15O2) and the radioaerosol of 99mTcO4-; (B) the patency of the airways to the ischemic regions; and, most importantly; (C) the much slower tracer removal from lung tissue with a stagnant circulation as opposed to the surrounding normal lung. The 11CO and C15O label the hemoglobin in red blood cells, and the C15O2 labels water in the circulation and in the stagnant ischemic region. The TcO4- probably labels the albumin of the plasma in the embolized regions and in the circulating blood. Experiments involving pulmonary embolism in dogs, proved by pre- and post-mortem angiography and gross post-mortem examination, show that positive ischemic lesions (hot spots) are observed, after TcO4- aerosol and C15O2 gas inhalation, in the embolized region on the same day. Clinical trials with aerosol-inhalation method in suspected pulmonary embolism and now under way.
 ...
PMID:Imaging experimental pulmonary ischemic lesions after inhalation of a diffusible radioaerosol: concise communication. 83 71

In 52 patients with pulmonary embolism, the deep venous circulation of the lower extremities and the pulmonary arterial blood flow were studied with albumin macroaggregates labeled with technetium-99m. A gamma camera with a data processor was used for this study. At the beginning, the perfusion lung scintigrams were abnormal in all the patients, 42 of them also had abnormal phlebograms and in half of them the perfusion by lung scintigram became normal when the phlebograms were obtained. These findings establish the high incidence of deep thrombophebitis in the legs of the patients with pulmonary embolism and indicate that the leg is of the most important 'thrombi factory' and that the deep venous circulation of the extremities should be studied to determine the primary cause of the pulmonary embolism.
 ...
PMID:Thromboembolic disease. 93 91

Based upon experience with 563 patients, the 131 I fibrinogen test has proven a reliable method for the diagnosis of acute leg vein thrombosis. Investigations correlated by means of roentgenological phlebography performed by routine technique in 83 patients showed similar results in 77% of the cases. Analyzing the negative results of 23%, we consider 19% of the discrepancies to be due to faulty phlebographic and 4% to faulty fibrinogen results. Phlebography may reveal false positive results in recurrent thromboses and false negative results in thrombosis of the lower legs. The fibrinogen test may reveal false positive results after trauma, fractures, and in cases of superficial phlebitis and arthritis. Pelvic venous occlusions are detectable by radionuclid venography. This method is non-invasive (injection of 99m Tc albumin particels or microspheres in less than 1 ml, by means of a very thin needle into a dorsal foot vein). A lung scan is obtained in every examination. The results conformed in 89% of 250 patients with those obtained from Doppler ultrasonic investigations. Two thirds of all pelvic vein thromboses were located on the left side. Perfusion defects of the lungs were probably caused by pulmonary embolism (lung scanning) and were found in an average of 54% of all leg and pelvic vein thromboses (in thrombosis of the lower legs in 35%, of the thigh in 57% and of the pelvic vein in 70%). These figures are in good conformity with pathological-anatomical data concerning the frequency of pulmonary emboli and infarctions in leg and pelvic vein thrombosis.
 ...
PMID:[Detection of venous occlusions of the leg and pelvis by means of nuclear medicine]. 100 40

A prospective double-blind study was instituted in a group of 150 general surgical patients to test the effectiveness of mini-dose heparinization in the pre- and postoperative periods. There was a 21 per cent reduction in the incidence of deep venous thrombosis in the heparin treated group. A radiopharmaceutical imaging technique with 99m-technetium macroaggregated albumin was used to evaluate the deep venous system. The procedure proved to be simple, safe, and painless; however, it was difficult to differentiate venous stasis from deep venous thrombosis. A negative study was good evidence that deep venous thrombosis did not exist. An additional benefit of this procedure was that a perfusion lung study could be obtained which provided additional information regarding pulmonary embolism without injecting additional radiopharmaceutical. Again, the negative perfusion lung study provided more information.
 ...
PMID:Evaluation of mini-dose heparin administration as a prophylaxis against postoperative pulmonary embolism: a prospective double-blind study. 109 61

A ventilation agent that provides good quality lung images, which is cheap, easy to use and non-toxic, with a low radiation dose, has long been sought. Technegas, an ultrafine aerosol of technetium-99m-labelled carbon, was developed with these qualities in mind. We have studied Technegas in a clinical setting to evaluate some of these qualities. Twenty-five patients referred with a diagnosis of suspected pulmonary embolism were investigated during the same study using both krypton-81 m and Technegas as ventilation agents in conjunction with 99mTc-macroaggregated albumin as a perfusion agent. Technegas provided images which were of satisfactory quality. Images were obtained relatively easily and without discomfort to the patient, and Technegas has the advantage of always being available. A semi-quantitative regional assessment was employed which showed a good correlation (r = 0.499, P less than 0.001) between Technegas and krypton-81 m ventilation. We report on an effect not previously found to be significant, that is lung regions were better ventilated with Technegas than with krypton-81 m. This altered the diagnostic probability rating of pulmonary embolism in a number of patients (n = 3, 12%) compared with krypton-81 m. This effect was also noted in a further 8 patients (32%) without a change in the diagnostic probability. We offer possible explanations for this phenomenon.
 ...
PMID:An evaluation of Technegas as a ventilation agent compared with krypton-81 m in the scintigraphic diagnosis of pulmonary embolism. 838 22

The aim of this study is to evaluate the safety and clinical usefulness of lung scintigraphy using 99mTc-technegas produced by the evaporation of pertechnetate elution at 2500 degrees C. Lung images were recorded by the gamma camera-computer system after a few deep inspirations of 99mTc-technegas. One healthy volunteer and 32 patients including 10 with lung cancer, 8 with chronic obstructive lung disease, 5 with pulmonary embolism, 2 with interstitial pneumonia, 2 with bronchiectasis and 12 with other various disease were studied. Delayed images were taken at more than 1 hour later in one healthy and 13 patients to investigate the interval changes of the intrapulmonary distribution of 99mTc-technegas. Obvious differences of radioactive distribution between early and delayed image were observed in only 2/14 cases. Penetration index (P.I.) averaged 0.81 +/- 0.11 for early images and 0.85 +/- 0.12 for delayed image. There was no significant difference between P.I. for early and delayed images. More than 97 MBq of 99mTc-macroaggregated albumin (99mTc-MAA) were required to obtain the adequate perfusion images after the acquisition of lung images with about 37 MBq of 99mTc-technegas. Bronchial deposits of 99mTc-technegas were shown in 12/33 cases and pathological defects in 26/32 patients (81.3%). Twenty three of 33 cases also had a perfusion scintigraphy with 99mTc-MAA. Ventilation perfusion mismatches were presented in 5/5 patients with pulmonary embolism and 1/10 patients with lung cancer. The safety was confirmed in all cases and clinical usefulness in 30/32 patients (94%). In conclusion, the safety and clinical usefulness of lung scintigraphy with 99mTc-technegas were proven in this study.
 ...
PMID:[Clinical evaluation of lung scintigraphy with 99mTc-technegas]. 196 28

The authors report their experience with the use of Tc-99m DTPA aerosol following a perfusion lung scan. The study includes 422 consecutive patients with suspected pulmonary embolism. The final diagnosis was determined by (a) clinical follow-up for 2 months or more, (b) pulmonary angiography, or (c) autopsy. There were 79 patients (19%) who had a normal or near-normal perfusion study and in whom no aerosol study was required. Interpretation groups were classified and divided as follows: Normal or low probability 281 (66.5%) High probability 75 (18.0%) Intermediate 60 (14.0%) Technically inadequate 6 (1.5%) There was autopsy or angiographic confirmation of 72 patient studies with confirmation of the scan diagnosis in 29 of 31 classified as normal or low probability and 24 of 25 classified as high probability. The background perfusion albumin activity was not computer-subtracted from the combined aerosol-perfusion image. Technical improvements included the use of eight standard views for both the perfusion and the subsequent aerosol scan, and the use of 75 mCi (2,775 MBq) of Tc-99m DTPA in the radioaerosol nebulizer. This allowed for easy accumulation of more than three times the count rate in a posterior aerosol image when compared with the previous posterior perfusion image. The authors' experience shows that the perfusion lung scan followed by this radioaerosol technique is a reliable means to evaluate suspected pulmonary embolism.
 ...
PMID:Utility of Tc-99m DTPA aerosol inhalation scans following perfusion lung scans in the diagnosis of pulmonary embolism. 218 Jun 7

A total of 336 cases received a ventilation-perfusion(V/Q) scan for the detection of pulmonary embolism (PE). Among these, 155 cases simultaneously underwent a successful radionuclide venography study (RNV) of the lower limbs using Tc-99m macro-aggregated albumin (MAA). Concomitant pulmonary arteriography (PA) was performed in 120 cases. Fifty-four of these 120 cases successfully completed the RNV scan. There was a statistical significance in the V/Q scan for the detection of PE as confirmed by the PA (p less than 0.0001). The positive predictive value (PPV) of the RNV for PE was 75% (3/4). The negative predictive value (NPV) was 48% (24/50). The sensitivity and specificity were 10% (3/29) and 96% (24/25) for the 54 patients who had both the RNV scan and PA. For the 155 patients who had simultaneous V/Q and RNV scans, there was no statistically significant correlation between these two scans. The PPV, NPV, specificity and sensitivity were 42%(8/19), 75%(103/136), 90%(103/114) and 20%(8/41), respectively. Despite the low sensitivity and no significance of positive RNV for diagnosis of PE, RNV is still recommendable because it is a simple, non-invasive, simultaneous procedure during perfusion lung scan and has high specificity.
 ...
PMID:Diagnostic value of Tc-99m MAA radionuclide venography of lower extremity: as a simultaneous procedure of ventilation-perfusion scan for pulmonary embolism. 226 40

Early diagnosis of deep venous thrombosis and pulmonary thromboembolism is still a clinical problem and led to the development of non invasive diagnostic methods using radioactive tracers. There are 2 principles of procedures. One is diagnosing deep venous thrombosis with the 125 (131) iodine-fibrinogen uptake-test. The use of 125 (131) J fibrinogen, its advantages and disadvantages are described. Others are imaging techniques developed as an alternative to ascending contrast venography still considered as the "golden standard", using 99m Tc labelled microspheres of human serum-albumin or Tc 99m labelled red blood cells (blood pool imaging). In spite of certain discrepancies a good correlation of 90% exists, between the imaging methods mentioned. Several authors reported a sensitivity of 87% and a specificity of 85% as compared with Doppler-ultrasound Investigations of lower extremities. A great advantage of radionuclidvenography is the possible combination with lung-perfusion scanning for the diagnosis of pulmonary embolism. Lung-perfusion- and ventilation-studies are still the only non invasive method to diagnose pulmonary embolism. Sensitivity of this method is very high, specificity improves with taking in account predisposing factors of developed deep vein thrombosis. Indium 111 or 99m Tc labelled monoclonal antifibrinantibodies are developed recently: an imaging agent suitable for evaluation of both pelvic and lower extremity vein thrombosis. First promising results were published last year and it seems, that this reliable imaging agent for clots and thrombo-embolic diseases will fill this diagnostic need in the future.
 ...
PMID:[Isotope studies in the diagnosis of venous thromboses and lung embolism]. 269 14


1 2 3 4 5 6 7 Next >>