Acta radiologica. Supplementum最新文献

{"title":"Interstitial MR lymphography using Gd-carrying liposomes.","authors":"B Misselwitz,&nbsp;A Sachse","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The detection of metastasis in lymph nodes is greatly enhanced by the use of contrast media. Interstitial injection of lymphography contrast agents requires only injection of a low dose of the agent, and leads to high accumulation in regional lymph nodes with only minor side effects. We were able to show the suitability of liposome-encapsulated gadobutrol as an interstitially injectable lymphography contrast agent in an experimental animal model. For screening of possible lymphotrophic compounds a guinea pig model was used. Accumulation of the contrast agent in 3 successive lymph node groups was determined 4 h after subcutaneous injection of the contrast agent (about 0.1 ml of a 30 mmol Gd/l solution resulting in a total dose of 10 mumol/kg) into the interdigital skin fold of a hind limb. The Gd concentration in the first lymph node group (popliteal) was 540 mumol/l (16% dose/g tissue), in the second group (inguinal): 260 mumol/l (8% dose/g tissue), and in the third group (iliac): 910 mumol/l (27% dose/g tissue). Moreover, this compound was completely eliminated and well tolerated.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"51-5"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20184501","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 MR angiography. Methods, limitations and possibilities.","authors":"M Kouwenhoven","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Whereas conventional MRA relies on enhanced blood signal from flow-induced magnitude and/or phase effects, gadolinium-enhanced MRA relies mainly on the enhanced blood signal caused by the reduced relaxation time T1. This has a large impact on the imaging technique used, as well as on the imaging volume orientation and the total scanning time. In general, gadolinium-enhanced MRA is faster, with fewer artifacts than MRA without contrast agents.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"57-67"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20184502","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":"Nuclear oncology and the Imagene concept.","authors":"J L Urbain,&nbsp;M C Vekemans,&nbsp;S K Lemieux,&nbsp;S C Cosenza,&nbsp;V K Senadhi,&nbsp;B N Milestone,&nbsp;E P Reddy","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Over the past 2 decades we have witnessed an explosion of new radioisotopic tracers aimed at detecting, staging and eventually treating tumors. In fact, nuclear oncology has evolved into a field on its own. Aside from aspecific radioisotopic tracers such as thallium 201 or gallium 67, clinicians and oncologists can now use specific radiolabeled monoclonal antibodies and metabolic tracers. In the near future, molecular probes based on the sequencing of the human genome with an exquisite specificity should also become available. In this article, we shall review the most recent developments in this new field.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"21-8"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20184497","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":"Characterization of polyethyleneglycol-stabilized, manganese-substituted hydroxylapatite (MnHA-PEG). A potential MR blood pool agent.","authors":"K Adzamli,&nbsp;R B Dorshow,&nbsp;M R Hynes,&nbsp;D L Nosco,&nbsp;M D Adams","doi":"","DOIUrl":"","url":null,"abstract":"<p><strong>Purpose: </strong>To optimize the performance (or efficacy) of a potential particulate blood pool agent for MR angiography by varying the particle size. The colloidal system under investigation was polyethylene glycol-stabilized manganese-substituted hydroxylapatite (MnHA-PEG).</p><p><strong>Material and methods: </strong>Several MnHA-PEG formulations were prepared using various length PEGs (MW = 140-2000). Products were characterized in vitro by dynamic light scattering (DLLS), field flow fractionation (FFF), and relaxometry; and in vivo by blood clearance kinetics in rabbits, and by analytical electron microscopy (EM).</p><p><strong>Results: </strong>The particle size distribution (PSD) consisted only of small particles (approximately 10-nm diameter) when approximately 40 mo1% PEG was used. At approximately 20 mo1% PEG, larger particles (approximately 100 nm), which are aggregates of the small ones, were also present. The water proton relaxation profiles of the particles in plasma were different from that of the free Mn2+. In plasma, the large aggregates were broken down into the smaller particles which were stable. Although the small particles were efficient relaxation enhancing agents, they were cleared from the blood approximately 3 times faster than the approximately 100-nm diameter aggregates, probably as a consequence of leakage into the extravascular space. Variation of PEG size had no effect on particle characteristics or on blood clearance. Analytical EM of rabbit liver specimens indicated some retention of Mn in mitochondria at the time point when Mn content of other subcellular structures returned to baseline.</p><p><strong>Conclusion: </strong>DLLS and FFF are complementary techniques for sizing particulate MR contrast media. Small MnHA particles are more efficient T1-shortening agents than large ones but they are prone to leakage from the vascular space. Within the MW range explored, the length of PEG molecule had no effect on blood clearance of the MnHA particles. Larger aggregates of MnHA-PEG break down into stable small particles in plasma. Mn clears from the subcellular structures within hepatocytes within 60 min after i.v. MnHA-PEG administration except from the mitochondria in which it appears to accumulate.</p>","PeriodicalId":7159,"journal":{"name":"Acta radiologica. Supplementum","volume":"412 ","pages":"73-8"},"PeriodicalIF":0.0,"publicationDate":"1997-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"20182564","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}