Thrombosis after phlebography: A comparison of two contrast media

In two studies 267 consecutive patients with suspected leg vein thrombosis were examined by an¹²⁵I-fibrinogen uptake test (¹²⁵I-FUT) and by phlebography. The ionic meglumine calcium metrizoate (Isopaque Cerebral) was used as the phlebographic contrast medium in 161 patients, and the non-ionic metrizamide (Amipaque) was used in 106. In these two groups 47 and 41 patients, respectively, had normal phlebograms as well as an initially normal¹²⁵I-FUT. After phlebography 29 (62%) of the patients who had received meglumine metrizoate had a significant rise in fibrinogen uptake, while such a rise was not found in patients examined with metrizamide. Repeat phlebography showed fresh deep-vein thrombosis in seven of the nine patients with increased uptake, indicating a complication rate of 48%. Consequently, we now use metrizamide in leg phlebography; because of its expense a radioisotope test is employed as a screening procedure. This work was supported by grants from the Swedish Medical Research Council (14X-2872) and the Swedish Association against Heart and Lung Diseases.     

The incidence of cardiac arrhythmias during intravenous digital subtraction angiography: a comparison of peripheral and central injections

Intravenous digital subtraction arteriography (IV-DSA) was carried out in 204 patients with arteriosclerotic peripheral vascular disease using the non-ionic contrast medium iopamidol 370. In 124 patients the injection was made into an antecubital vein and in 80 into the right atrium. Rhythm strip electrocardiograms showed no significant difference in incidence or type of arrhythmias between either injection method (p greater than 0.95).     

Assessment of coronary artery disease by post-mortem cardiac MR

Objectives

Minimally invasive or virtual autopsies are being advocated as alternative to traditional autopsy, but have limited abilities to detect coronary artery disease. It was the objective of this study to assess if the occurrence of chemical shift artifacts (CSA) along the coronary arteries on non-contrast, post-mortem cardiac MR may be used to investigate coronary artery disease.

Methods

We retrospectively compared autopsy and CT findings of 30 cases with significant (≥75%), insignificant (<75%), or absent coronary artery stenosis to post-mortem cardiac MR findings. The chi-square test was used to investigate if the occurrence of CSA depends on the presence or absence of stenosis. Sensitivity, specificity and predictive values were calculated for each finding.

Results

CSA indicates the absence of (significant) stenosis (p < 0.001). The occurrence of paired dark bands in lieu of CSA on post-mortem cardiac MR suggests (significant) coronary arteries stenosis (p < 0.001). Both findings have a high specificity but low sensitivity.

Conclusions

CSA is a marker of vessel patency. The presence of paired dark bands indicates stenosis. These criteria improve the ability of minimally invasive or virtual autopsy to detect coronary artery disease related deaths.     

The effects of contrast media on the cardiac conducting system in coronary angiography

Comparative study of ionic and nonionic contrast media was carried out to investigate the effects on the cardiac conducting system caused by sodium ion and osmolality in coronary angiography. We evaluated the effects on the cardiac conducting system by 5% Glucose (5% GL), 20% glucose (20% GL), saline (SL), Ioxaglate 320 (IOX, ionic low-osmolar contrast medium, ionic LOCM), Iopamidol 370 (IOP 370, non ionic low-osmolar contrast medium, nonionic LOM) and 60% Diatrizoate (DTA, high-osmolar contrast medium, HOCM). In 18 patients who underwent coronary angiography, the effects on the cardiac conducting system were investigated using P-P time, A-H time, H-V time, QTc, T-wave height from His bundle electrogram and surface electrocardiogram. Prolongations of P-P time, A-H time and QTc with 20% GL, DTA were significantly longer than with IOX, IOP 370, 5% GL, and SL (p less than 0.01). There was almost no difference among 5% GL, SL, IOX, and IOP 370 in both P-P and A-H times. Also, prolongations of QTc with IOX, IOP 370 were longer than with 5% GL and SL (p less than 0.01). H-V time was not significantly prolonged with all solutions. The change of T-wave height with IOX was significantly greater than with IOP 370 (p less than 0.01). The change of T-wave height with SL was significantly greater than with 5% GL and that of T-wave height with 60% DTA was significantly greater than with 20% GL (p less than 0.01). Prolongations of P-P time, A-H time, QTc and changes of T-wave height were correlated with osmolality (p less than 0.01). These observations suggested that main factor of the disturbances of the cardiac conducting system excluding change of T-wave height was high osmolality of solution. Sodium ion took little part in the disturbances, and the factor of T-wave height change was not only due to the osmolality but also due to the concentration of sodium ion. LOCM caused much less significant disturbances of the cardiac conducting system than HOCM. There was almost no difference between non-ionic LOCM and ionic LOCM excluding the change of T-wave height.     

A qualitative comparison of two contrast media for cerebral angiography. A clinical method

Summary A qualitative comparison of two contrast media for cerebral angiography with regard to contrast should, preferably, be based on a comparison made in two different hemispheres of one patient. Two problems then arise which make evaluation difficult. Vasodilation occurs after the first contrast injection as a result of which the second contrast medium to be compared flows into a dilated vascular tree. In addition, in the case of a comparison in two different hemispheres, variations of image geometry occur, resulting in differences of sharpness and contrast. The method of solving these problems is discussed and is illustrated by a comparison of two contrast media which might be expected to produce differences in contrast because of their physical properties. The results of this clinical comparison show that the expected differences can be partly demonstrated.     

A survey of contrast media used in coronary angiography

In recent years, various contrast media have been developed for use in coronary angiography. These contrast media may be divided into ionic contrast media of high osmolality, those of low osmolality, and nonionic contrast materials. We conducted our own clinical studies with 40 patients. In random succession a standard contrast medium (ionic, of high osmolality) and a new-generation contrast medium (either nonionic or ionic with low osmolality) were injected into the right and left coronary arteries. After each injection we measured the systolic and diastolic blood pressure using a liquid-filled coronary catherter. In addition, the change in the length of the cardiac cycle was registered in terms of the R-R interval (in ms) and at the same time, leads I, II, and III of the ECG were recorded. We studied the influence of the various contrast media on the activity of ATPase in in vitro experiments, using Lasser and Lang's [30]. When ionic contrast media of low osmolality and nonionic contrast media were utilized the heart rate showed no change. Disturbances of rhythm such as ventricular tachycardia or fibrillation were not observed. All of the contrast media used produced the same ECG changes. These changes can be ascribed to the inhibition of ATPase. The arterial blood pressure was lowered significantly only by ionic contrast media of high osmolality only.     

A comparison between iohexol and metrizamide, two nonionic contrast media, in aorto-femoral angiography

Iohexol, a recently developed non-ionic contrast medium, is shown to be well tolerated on aorto-femoral angiography. The aortic injection of 40 ml of iohexol (350 mg I/ml) was usually associated with a moderate sensation of heat and an absence of pain. A transient fall in blood pressure, no different from that resulting from metrizamide, was associated with some increase in heart rate.     

Projection imaging of the right coronary artery with an intravenous injection of contrast agent.

Contrast-enhanced (CE) MR angiography of the right coronary artery (RCA) was performed using 2D thick-slice projection imaging with a small (8 mL) intravenous injection of contrast agent in six volunteers. With a tight contrast bolus injection, the RCA was enhanced for a few seconds after the contrast bolus was washed out of the right ventricle. This allowed data to be acquired when only the RCA was enhanced. Using 2D thick-slice magnetization prepared steady-state free precession (SSFP) imaging, background signal was suppressed and a complete data set was acquired in three heartbeats. A mean vessel length of 7.1 +/- 0.9 cm was depicted with a signal-to-noise ratio of 11.8 +/- 0.7 and contrast-to-noise ratio of 6.1 +/- 0.6. Thick-slice 2D projection CE SSFP is a promising method to depict the RCA.     

Preheated contrast media: the advantage of intravenous injection

A study was performed to evaluate the effectiveness of intravenous injections with preheated contrast as opposed to room temperature contrast. Methods of preheating contrast are described as well as the accompanying complications and treatments of side effects. This article explains why preheated contrast media is a recommended procedure.     

Optimization of low-osmolality contrast media for cranial CT: a dose comparison of two contrast agents

A prospective, randomized, double-blind comparative study of 200 patients was made to examine the image quality, safety, and costs of 100 ml of ioversol-320 (32 g iodine) and 150 ml of iohexol-300 (45 g iodine) in patients undergoing cranial CT. We found no statistically significant difference in image quality between the two low-osmolality, nonionic contrast agents at these doses. There was a statistically significant (p = .02) difference in the occurrence of minor to mild adverse effects caused by ioversol (n = 0) as compared with iohexol (n = 5). No patient in either group experienced any major contrast-induced reactions. Contrast media costs were 34% less in patients receiving 32 g of iodine as compared with those receiving 45 g of iodine. This study demonstrates that high-quality cranial CT scans are possible even with a reduced volume of low-osmolality contrast medium, and that the potential cost savings are significant.     

Opening of the blood-brain barrier by intravenous contrast media in euvolemic and dehydrated rabbits

It has been suggested that intravenous injections of hypertonic contrast media when used in computed tomography and digital subtraction angiography might raise plasma osmolality sufficiently to open the blood-brain barrier (BBB). The current investigation establishes the threshold of plasma osmolality that causes the the opening of the BBB in euvolemic and dehydrated rabbits. Euvolemic rabbits were allowed food and water ad libitum. Dehydrated rabbits received 4.0 mg/kg of furosemide intramuscularly and were deprived of water for 72 hours. Meglumine/sodium diatrizoate 76 per cent (n = 28) or mannitol 20 per cent (n = 12) was administrated intravenously, at a rate of 25 mmol/kg body weight/hour for 2, 3 or 4 hours. Plasma osmolality, blood iodine concentration, blood pressure, heart rate and hematocrit were assessed at regular intervals. Evans blue and 99Tcm-DTPA were used simultaneously as tracers for BBB opening. Rating of BBB opening with 99Tcm-DTPA correlated well with Evans blue staining (r = 0.863, p less than 0.001; n = 42). BBB opening was related to plasma osmolality and was similar for both contrast media and mannitol. Widespread BBB opening occurred above 400 mmol/kg while focal BBB opening occurred above 370 mmol/kg. Dehydration per se increased plasma osmolality but did not reduce the threshold for BBB opening.     

Comparison of the side-effects of low-osmolar contrast media in intravenous urography

The subjective side-effects of almost equivalent intravenous iodine doses of the three new low-osmolar contrast media, ioxaglate (Hexabrix), iopamidol (Niopam) and iohexol (Omnipaque) have been recorded and are found to be generally comparable. Urticaria occurred more frequently with ioxaglate than with the other contrast media and there was a tendency for ioxaglate to cause more nausea. Pain at the injection site occurred less often with ioxaglate than with iohexol. If low-osmolar contrast media are to be used in intravenous urography the relative cost of each is important, there being as yet insufficient data concerning the relative incidences of major reactions.     

Comparison of low-osmolar contrast media in cardiac angiography

Two hundred and twenty-five patients investigated by left ventricular, coronary artery and/or proximal aortic angiography were randomly assigned to one of three contrast medium groups (Hexabrix 320, Niopam 300 or Omnipaque 300). Subjective response to injection of contrast medium was noted at the time of investigation and during the next 24 h. No significant difference was found between the three currently available low-osmolar contrast media.     

不同对比剂用量方案在双源CT冠状动脉成像及心脏结构显示方面的研究

目的:选择适宜的对比剂用量,改善双源CT冠状动脉成像时对心脏结构的显示能力。方法:160例接受Defini-tion第一代双源CT冠脉CTA检查的患者随机分为4组,对比剂用量分别为:A组=采集时间×注射流速(X ml),B组=(X+5)ml,C组=(X+10)ml,D组=[X+(15～20)]ml。各组均采用碘海醇(350mgI/ml),体质量<75kg者注射流率为4.8～5.0ml/s;体质量≥75kg者注射流率为5.5ml/s。应用Circulation分析软件,采用双盲法评价图像质量。分别测量各组冠状动脉各段、左右心室CT值,观察并记录对比剂伪影及严重程度、对比剂混合液是否均匀、室间隔显示是否清晰等。采用单因素方差分析法(One-way ANOVA)比较组间CT值、图像质量评分等有无差异,采用χ2检验比较室间隔等结构显示情况及对比剂伪影等。结果:各组间一般情况、质量评分、冠脉各段和左心室CT值等差异无统计学意义(P均>0.05)。右心室腔内CT值A、B、C、D组分别为(142.1±35.5)HU、(144.4±43.5)HU、(186.1±66.1)HU、(223.3±119.3)HU,C组与A、B、D组间差异均有统计学意义。各组室间隔尚能分辨(2分)的例数差异无统计学意义,但C、D组显示清晰(3分)的例数多于A、B组;C组条状伪影少于D组。综合分析,C组对比剂方案优于其他组。结论:本研究采用个性化的对比剂方案,对比剂用量=扫描采集时间×流率+10ml,结合患者体质量和体质量指数(BMI)计算对比剂注射流率,可以获得良好的冠脉CTA图像及较为满意的心脏结构、肺动脉显示效果,有一定临床应用价值。     

Adverse reactions following two separate intravascular injections of contrast media in the same patient. A comparison between iohexol and monomeric ionic media

Adverse reactions following contrast medium injections in 26 non-comparative and parallel trials were extracted from the iohexol vascular clinical trial program in Northern Europe. Six hundred and forty-one patients (13-88 years old) in whom information was available about a vascular contrast medium examination before the iohexol clinical trials were included, enabling a retrospective within patient comparison of adverse reactions. Iohexol gave a lower recurrence frequency (approximately 3.5 times) of reactions than ionic monomers in patients who previously experienced adverse reactions to vascular contrast media. In order to overcome some of the drawbacks with the present retrospective design, prospective comparative studies are recommended.     

A comparison of planar and tomographic thallium scintigraphy in patients with coronary artery disease

Planar and tomographic scans from 57 patient are compared and related to coronary arteriographic results. Tomography identified inferior and septal defects not seen on planar imaging. Planar imaging better identified apical defects. Lesions of the left circumflex were poorly defined by both techniques.     

A comparison of planar and tomographic thallium scintigraphy in patients with coronary artery disease

Planar and tomographic scans from 57 patients are compared and related to coronary arteriographic results. Tomography identified inferior and septal defects not seen on planar imaging. Planar imaging better identified apical defects. Lesions of the left circumflex were poorly defined by both techniques.