Acta radiologica. Supplementum最新文献

{"title":"Diagnostic imaging of acute pulmonary embolism.","authors":"F Christiansen","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The common strategy of combining clinical information, lung scintigraphy and pulmonary angiography in the diagnosis of acute pulmonary embolism (PE), has many limitations in clinical use. The major causes are that pulmonary angiography and lung scintigraphy are not universally available, and that pulmonary angiography is very expensive. The purpose of this thesis was to analyse different aspects of validity in regard to lung scintigraphy, pulmonary angiography, spiral CT, and ultrasound of the legs, with the subsequent intention of discussing new diagnostic strategies. Observer variations in lung scintigraphy interpretation when applying the PIOPED criteria were tested in 2 studies with 2 and 3 observers respectively and expressed as kappa values. The ability to improve agreement in lung scintigraphy interpretation was tested by training 2 observers from different hospitals. The impact of 3 observers' variations in lung scintigraphy interpretation when compared to pulmonary angiography, was tested by comparing the ROC areas of the observers. The value of combining subjectively derived numerical probabilities and the PIOPED categorical probabilities in lung scintigraphy reporting was compared to using the PIOPED categorization only, and this was tested by comparing ROC areas. The sensitivity and specificity of detecting an embolic source in the deep veins of the legs by ultrasound as a sign of PE when lung scintigraphy is inconclusive, was tested by comparison with pulmonary angiography. The sensitivity and specificity of spiral CT, compared to pulmonary angiography, was tested by comparison to pulmonary angiography. The inter- and intra-observer kappa values were in the range of moderate and fair. It was not possible to achieve better kappa values after training. Although observer variations were substantial, the accuracy did not differ significantly between the 3 observers. Incoorporating subjectively derived probabilities into lung scan reporting could not reduce the number of inconclusive investigations. Sensitivity and specificity of ultrasound in detecting PE was 0.70 and 0.97, respectively. However, 2 patients (of 9) had deep venous thrombosis and no pulmonary emboli at angiography. The sensitivity and specificity of spiral CT was 0.90 and 0.96, respectively. The observer variations at lung scintigraphy are substantial and may be difficult to improve between hospitals, even though the accuracy of observers in general is good. Although subjectively derived interpretation criteria did not show to be useful when added to categorical interpretation criteria, they may be useful when substituting established criteria. Despite recent progress in refining interpretation criteria, a substantial fraction of the patients still need pulmonary angiography to be performed. However, in many patients pulmonary angiography is not performed as prescribed. Spiral CT and ultrasound of the legs is a new favourable diagnostic strategy with a high validity ","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"410 ","pages":"1-33"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20054064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Alteration of electronic relaxation in MR contrast agents through de-novo ligand design.","authors":"R B Shukla,&nbsp;K Kumar,&nbsp;R Weber,&nbsp;X Zhang,&nbsp;M Tweedle","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The longitudinal electronic state lifetime of the paramagnetic Gd metal within a macrocyclic ligand core can be increased by designing ligand frames that alter the vibronic interactions between the ligating atoms and the metal. We conducted the first pulsed EPR studies that demonstrated the increase in the longitudinal state lifetimes of the electronic subsystem at cryogenic temperatures. We also designed a simple sucrose/ water model that significantly increases the rotational correlation time in solution of the Gd chelate. This model system enables relaxivity studies at ambient temperatures that more readily interrogate exchange and electronic contributions to the inner-sphere relaxivity by effectively removing the rotational correlation time contribution. These results combined with water residence (Q) measurements suggest that rigidification of the macrocyclic core or that of the pendant arms increases the longitudinal electronic state lifetime of the paramagnetic Gd metal. This increased lifetime possibly contributes to the improved relaxivity for the rigid Gd chelates observed in the sucrose/ water model studies.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"121-3"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20182569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Contrast-enhanced lymphography. CT or MR imaging?","authors":"T J Vogl,&nbsp;M Bartjes,&nbsp;K Marzec","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Lymphography is the radiological visualization of the lymph vessels and lymph nodes with contrast material. History and different modes of visualization are compared.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"47-50"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20184500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Myocardial perfusion by contrast-enhanced echocardiography and dynamic contrast-enhanced MR imaging.","authors":"M Lombardi,&nbsp;D Rovai,&nbsp;P A Rinck,&nbsp;A L'Abbate","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The evaluation of myocardial perfusion is of clinical relevance in ischemic heart disease. New noninvasive and nonionizing imaging techniques for the evaluation of myocardial perfusion are progressing. The present status and the future development of echo-contrast and dynamic-contrast MR imaging are discussed for myocardial perfusion studies.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"79-84"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20184504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physical, chemical and biological evaluations of CMD-A2-Gd-DOTA. A new paramagnetic dextran polymer.","authors":"C Corot,&nbsp;M Schaefer,&nbsp;S Beauté,&nbsp;P Bourrinet,&nbsp;S Zehaf,&nbsp;V Bénizé,&nbsp;M Sabatou,&nbsp;D Meyer","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Purpose: </strong>We investigated the synthesis and physical, chemical and biological characterisation of a carboxymethyl-dextran polymer substituted with the paramagnetic macrocyclic complex Gd-DOTA using an amino spacer.</p><p><strong>Material and methods: </strong>The product was synthesised in 4 steps. Using rigorous purification conditions in each step, a polymer was obtained, i.e. CMD-A2-Gd-DOTA, whose polydispersity profile was comparable to the initial dextran (I = 1.66-Mw = 50.5 kDa). Approximately 22% of the glucose groups were replaced by Gd-DOTA and 39% were replaced by carboxyl groups. The paramagnetic efficacy of the polymer was 3 times higher than Gd-DOTA alone, which suggests that the injected doses of Gd(III) can be reduced. The vascular residence time of the polymer was measured in rats and rabbits, showing that the pharmacokinetics of the product is similar whatever the dose. Forty-five percent of the product was excreted in urine after 24 h and 1.64% was found in the liver. No acute toxicity was observed at the maximum dose injected (> 5 mmol Gd/kg) and the general biocompatibility of the product tested in vitro was comparable to that of Gd-DOTA.</p><p><strong>Results and conclusion: </strong>These results show the advantages of using paramagnetic macrocyclic complexes in the synthesis of macromolecules to preserve biological stability, in contrast with linear chelates. Additional studies will be carried out to demonstrate the benefits of this type of product, particularly in functional imaging.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"91-9"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20182566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"European Magnetic Resonance Forum Proceedings. New developments in contrast agent research 5th special topic seminar on magnetic resonance contrast agents. Santa Margherita Ligure, Italy, 5-7 June 1996.","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"7-138"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20214276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of hydroxyethyl-starch-ferrioxamine as an intravascular MR contrast agent for assessment of myocardial perfusion.","authors":"G Tian,&nbsp;J Shen,&nbsp;S Su,&nbsp;P Kozlowski,&nbsp;J Sun,&nbsp;B Xiang,&nbsp;J K Saunders,&nbsp;R Deslauriers","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Purpose: </strong>The present study was carried out to evaluate a new intravascular contrast agent hydroxyethyl-starch-ferrioxamine (HES-FO) for assessment of myocardial perfusion.</p><p><strong>Material and methods: </strong>Isolated pig hearts were perfused with a crystalloid cardioplegic solution in a Langendorff apparatus. MR images were acquired along the short cardiac axis using T1- and T2*-weighted methods. Gd-DTPA and HES-FO were used as the standard extracellular and test contrast agents, respectively.</p><p><strong>Results: </strong>We found that T1-weighted signal intensity was not significantly affected by HES-FO, but increased significantly in presence of Gd-DTPA. On the other hand, HES-FO resulted in a rapid, transient but significant decrease in T2*-weighted signal intensity. Although Gd-DTPA also decreased T2*-weighted signal intensity considerably, it took much longer for the T2*-weighted signal intensity to return to its initial steady-state with Gd-DTPA than with HES-FO. Moreover, increasing the dose of HES-FO (from 0.0023-0.0138 mmol/kg b.w.) had no effect on the time at which the T2* effect reached its maximum or on the duration of the T2* effect. However, these times and durations were affected significantly by increasing the dose of Gd-DTPA (0.0023-0.027 mmol/kg b.w.).</p><p><strong>Conclusion: </strong>The results suggest that HES-FO provides information regarding myocardial vascular flow which cannot be obtained using Gd-DTPA. It is expected that the combined use of intravascular and extracellular type contrast agents will allow more complete assessment of tissue perfusion.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"85-90"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20182565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multinuclear MR characterization of a new hepatobiliary contrast agent. Preliminary results.","authors":"L Vander Elst,&nbsp;F Maton,&nbsp;S Laurent,&nbsp;F Seghi,&nbsp;R N Muller","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Purpose: </strong>The aim of this work was to characterize the hepatobiliary contrast agent Gd-EOB-DTPA in various media: water solution, protein solution, phosphorylated metabolite solution, and excised and perfused liver tissue.</p><p><strong>Material and methods: </strong>Different NMR techniques were used: analyses of H-1 NMRD profiles, H-2 NMR relaxation rates, O-17 relaxation rates and chemical shifts, and P-31 relaxation rates and peak area.</p><p><strong>Results: </strong>The higher proton relaxivity of Gd-EOB-DTPA in water as compared to that of Gd-DTPA is due to a smaller distance r and to a longer tau R. The kinetic stability of the former compound in ATP solution is higher and it forms noncovalent bonds with human serum albumin. Internalization of the contrast agent by the hepatocytes does not impair the ATP metabolism of the cells but induces relaxation effects on the intracellular metabolites of the liver.</p><p><strong>Conclusion: </strong>Multinuclear MR studies allow the extensive characterization of MR contrast agents in in-vitro and ex-vivo model systems.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"135-8"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20182571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagnostic imaging of acute pulmonary embolism.","authors":"F. Christiansen","doi":"10.15197/jcdcc.00044","DOIUrl":"https://doi.org/10.15197/jcdcc.00044","url":null,"abstract":"The common strategy of combining clinical information, lung scintigraphy and pulmonary angiography in the diagnosis of acute pulmonary embolism (PE), has many limitations in clinical use. The major causes are that pulmonary angiography and lung scintigraphy are not universally available, and that pulmonary angiography is very expensive. The purpose of this thesis was to analyse different aspects of validity in regard to lung scintigraphy, pulmonary angiography, spiral CT, and ultrasound of the legs, with the subsequent intention of discussing new diagnostic strategies. Observer variations in lung scintigraphy interpretation when applying the PIOPED criteria were tested in 2 studies with 2 and 3 observers respectively and expressed as kappa values. The ability to improve agreement in lung scintigraphy interpretation was tested by training 2 observers from different hospitals. The impact of 3 observers' variations in lung scintigraphy interpretation when compared to pulmonary angiography, was tested by comparing the ROC areas of the observers. The value of combining subjectively derived numerical probabilities and the PIOPED categorical probabilities in lung scintigraphy reporting was compared to using the PIOPED categorization only, and this was tested by comparing ROC areas. The sensitivity and specificity of detecting an embolic source in the deep veins of the legs by ultrasound as a sign of PE when lung scintigraphy is inconclusive, was tested by comparison with pulmonary angiography. The sensitivity and specificity of spiral CT, compared to pulmonary angiography, was tested by comparison to pulmonary angiography. The inter- and intra-observer kappa values were in the range of moderate and fair. It was not possible to achieve better kappa values after training. Although observer variations were substantial, the accuracy did not differ significantly between the 3 observers. Incoorporating subjectively derived probabilities into lung scan reporting could not reduce the number of inconclusive investigations. Sensitivity and specificity of ultrasound in detecting PE was 0.70 and 0.97, respectively. However, 2 patients (of 9) had deep venous thrombosis and no pulmonary emboli at angiography. The sensitivity and specificity of spiral CT was 0.90 and 0.96, respectively. The observer variations at lung scintigraphy are substantial and may be difficult to improve between hospitals, even though the accuracy of observers in general is good. Although subjectively derived interpretation criteria did not show to be useful when added to categorical interpretation criteria, they may be useful when substituting established criteria. Despite recent progress in refining interpretation criteria, a substantial fraction of the patients still need pulmonary angiography to be performed. However, in many patients pulmonary angiography is not performed as prescribed. Spiral CT and ultrasound of the legs is a new favourable diagnostic strategy with a high validity in det","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"1 1","pages":"1-33"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83266996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasound contrast agents. Examples of blood pool agents.","authors":"J M Correas,&nbsp;O Hélénon,&nbsp;L Pourcelot,&nbsp;J F Moreau","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Purpose: </strong>The concept of contrast agents has been extended to ultrasonography (US) almost 30 years ago. Due to technical limitations, the development of US contrast agents (USCA) was slow until the last decade. The ideal USCA should be nontoxic, i.v. injectable, capable to cross the pulmonary capillary bed after a peripheral injection, and be stable enough to achieve enhancement for the total duration of the examination. It should provide not only Doppler but also B-mode enhancement, at a reasonable cost. The efficacy of the most advanced USCA has been reviewed.</p><p><strong>Results and conclusion: </strong>Doppler examinations improved in cases of deep or small vessels, vessels with low or slow flow, or vessels studied with a bad insonation angle. USCA also enhanced detection of flow within normal and abnormal vessels, including tumor and stenotic vessels. Ischemic areas were better delineated. Specific settings and software developed by US equipment manufacturers and US sequences (such as second harmonic imaging or transient imaging) prefigured the necessary adaptation of US units to the new potentials of USCA. Second harmonic properties will improve detection of smaller vessels including neovascularization associated with tumors. Targeting possibilities will increase the efficacy of USCA, and allow specific delivery of active drugs such as anticoagulants or cytotoxic compounds. New generations of USCA appear very promising, and are becoming part of the US future.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"101-12"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20182567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}