Detection of pharyngeal perforation: comparison of aqueous and barium-containing contrast agents

OBJECTIVE: We sought to assess the value of aqueous and barium-containing contrast agents in the detection of pharyngeal perforation. SUBJECTS AND METHODS: Visual and objective in vitro comparisons of an iodinated aqueous contrast agent, a 50% weight/volume barium suspension, and a 100% weight/volume barium suspension were performed. Moreover, to exclude pharyngeal perforation after surgery, we prospectively examined 109 patients by pharyngography, using the aqueous contrast agent and the 100% weight/volume barium suspension. All patients with a pharyngeal perforation were followed up clinically to exclude complications due to barium application. RESULTS: As opposed to the 100% weight/volume barium suspension, in vitro comparison between the aqueous contrast agent and the 50% weight/volume barium suspension yielded no substantial differences. Seventeen perforations could be detected with the aqueous contrast agent. Although 10 of 17 perforations could be slightly better visualized with the 100% weight/volume barium suspension, two perforations were missed with this agent. Five perforations were equally well detected with both. CONCLUSION: Because of a higher radiopacity, 100% weight/volume barium suspensions may more sharply delineate perforations. However, in contrast to aqueous contrast media, narrow pharyngeal perforations can be missed. Thus, the use of a 100% weight/volume barium suspension does not improve the detection of pharyngeal perforation.     

Shoulder arthrography: comparison of morbidity after use of various contrast media

This prospective study compares immediate and delayed patient discomfort in 177 patients following shoulder arthrography using intraarticular combinations of metrizamide, meglumine/sodium diatrizoate, meglumine diatrizoate, lidocaine, epinephrine, and air. Patients receiving conventional ionic monomeric positive contrast media had a 60% (90/150) incidence of moderate or severe delayed exacerbation of their baseline symptoms; only 14% (3/21) of patients receiving metrizamide, a nonionic contrast medium, had similar levels of postprocedural discomfort. Morbidity was somewhat diminished with the use of double-contrast (45%, 34/75) rather than single-contrast (75%, 56/75) examinations, and with avoidance of sodium-containing contrast agents or epinephrine. Nonionic or monovalent polymeric contrast media, despite their present high cost, may be the agents of choice if single-contrast arthrography is performed in joints (such as the shoulder, hip, and temporomandibular) associated with a high incidence of post-procedural pain.     

Herniography: comparison of morbidity and image quality after use of high and low osmolality contrast media

The morbidity and image quality after administration of three different contrast media were compared in 229 patients referred for herniography. Sixty patients received metrizoate 150 mg I/ml, 92 received metrizoate 200 mg I/ml, and 77 patients, ioxaglate 200 mg I/ml. Patient discomfort was single-blindedly assessed based on an arbitrary verbal rating scale. The number of patients with pain increased with the osmolality of the contrast media. Metrizoate 200 induced pain in 57% of the patients, metrizoate caused pain in 39%, and ioxaglate 200 in 18%. Hernia patients who received metrizoate 200 had pain significantly more often (72%) than patients without hernia (45%). Seven patients, predominantly young men, had a vasovagal reaction associated with the administration of contrast media. The image quality was sufficient after all injections of 200 mg I/ml. The results indicate that low osmolality contrast media with an iodine concentration of about 200 mg I/ml are well suited for herniography.     

Selective use of low-osmolar contrast media

Two thousand thirty-four consecutive patients presented for excretory urography within a 22-month period. Of 57 observed adverse reactions (incidence 2.8%), 54 occurred in 1219 low-risk patients injected with conventional ionic contrast media (HOCM) (incidence 4.4%) while three reactions were noted in the 815 high-risk patients receiving low-osmolar contrast media (LOCM) (incidence 0.4%). Despite strict enforcement of an unchanging list of high-risk criteria by the same pool of radiologists, LOCM use was not constant, increasing in use over time from 26.5% to 55.3% of urograms. In addition, frequency of LOCM selection increased transiently (from 33% to 52%) following a single life-threatening reaction to HOCM. Our results suggest that strict guidelines for use of LOCM are subject to loose individual physician interpretation. Physicians' perceptions of safety made it increasingly difficult to withhold LOCM and progressively more patients were included in high-risk groups.     

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.     

Marchiafava-Bignami disease: use of contrast media in CT and MRI

We report two cases of Marchiafava-Bignami disease studied by CT and MRI. Both patients displayed persistent confusion and a disconnection syndrome but had a favourable outcome. In both cases, CT with intravenous contrast medium revelaed enhancement of the corpus callosum in the early stage. MRI showed gadolinium uptake in both the genu and splenium of the corpus callosum in one case, 8 days after the onset. Three weeks after admission, cystic lesions appeared in the corpus callosum on MRI T1-weighted sagittal images in both cases. Contrast medium uptake may be useful in the diagnosis of Marchiafava-Bignami disease.     

Production and characterization of improved liposomes containing radiographic contrast media

The authors have investigated liposomes prepared by the reverse-phase evaporation method (REVs) and a modification of this technique that employs a microemulsifier (MREVs), for the delivery of radiographic contrast media (RCM) to the liver and spleen. The modification entailed substituting a Microfluidizer (Microfluidics Inc., Newton, MA) for the sonication step of the REV technique. The MREV procedure is amenable to large-scale production and continuous-flow operation and yields products with high RCM encapsulation. Efficiently entrapped are ionic, high-osmolar diatrizoate (24.38 +/- 2.62% versus 8.35 +/- 0.55%; MREV versus REV), and nonionic, low osmolar Iotrolan (Schering AG, Berlin, FRG) (24.84 +/- 2.13% versus 7.25 +/- 1.19%) RCM with iodine-to-lipid ratio of 1.5:1. The MREV procedure, therefore, has practical advantages over the REV method. High liver and spleen uptakes of Iotrolan-containing vesicles were noted in normal rats. The diatrizoate MREVs lost their contents on contact with serum, resulting in urinary excretion of this agent. Computed tomography values of splenic and hepatic sections, 1 hour after intravenous injection of Iotrolan MREV (500 mgI/kg), are 0.78, and 0.08 Hounsfield Units (HU)/mgI/kg, respectively (versus 0.01, and 0.006 HU/mgI/kg for free Iotrolan).     

Computed tomography contrast enhancement principles and the use of high-concentration contrast media

Numerous pharmacokinetic and physiologic interactions are involved in the utilization of iodinated contrast in computed tomography. Patient related factors, injection related variables including contrast material concentration, and intravascular and organ specific imaging techniques are but a few of the principles that must be understood. With the advancement of faster CT scanners, these factors must be considered for optimal contrast enhancement.     

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.     

Radiocontrast-associated renal dysfunction: a comparison of lower-osmolality and conventional high-osmolality contrast media

Nephropathy is an established untoward event associated with intravascular administration of conventional high-osmolality contrast media (HOM). It has not been shown previously that lower-osmolality contrast media (LOM) are less nephrotoxic in a clinical setting. We evaluate the ability to replace HOM with LOM (in lower-extremity angiography) to reduce the incidence of nephropathy. We use multiple definitions for contrast-induced nephropathy (six different magnitudes of rise of serum levels of creatinine or blood urea nitrogen in various periods). The incidences of nephrotoxic effects with LOM vs HOM in patients with presumed risk factors, including preexisting renal insufficiency and diabetes, are evaluated also. When all patients are considered, the incidence of contrast-induced nephropathy for LOM vs HOM (defined as an increase in serum creatinine level greater than 0.3 mg/dl and greater than 20% on day 1, 2, or 3 and on day 5, 6, or 7, is 7% vs 26% (p = .001). When only patients with preangiography azotemia are considered, the incidence of contrast-induced nephropathy for LOM vs HOM is 10% vs 41% (p = .017); for diabetic patients, regardless of preangiography creatinine level, the incidence is 10% vs 31% (p = .012). Although contrast-induced nephropathy may develop even in a patient with no risk factors who receives LOM, LOM is associated with a decreased incidence of this condition, to various degrees, depending on the presence of risk factors.     

正常肝脏与肝硬化螺旋CT扫描时对比剂最优化使用方法的研究

目的 研究正常肝脏与肝硬化肝脏在螺旋CT增强多期扫描中最佳对比剂剂量、注射流率及各组织强化达到峰值的时间。方法 正常肝脏、肝硬化肝脏各60例，按完全随机设计法各分成6组，分别以不同的注射剂量及流率在肘静脉注射非离子型对比剂，并在同一层面作连续多层扫描。最后测量各组织CT值，建立统计表并相互比较。结果 正常肝脏当注射剂量为1.5ml/kg时，3种不同的注射流率除主动脉强化峰值两两比较统计学上差异均有显著性意义外（P＜0．05），门静脉、肝实质差异均无显著性意义（P＞0．05）；当注射流率为2.5ml/s时，不同的剂量强化峰值主动脉、门静脉、肝实质差异均有显著性意义（P＜0．05）。肝硬化组：当注射剂量为2.0ml/kg时，3种不同的注射流率时肝实质在2.5ml/s与3.0ml/s时强化峰值差异有显著性意义（P＜0．05）。当注射流率为3.0ml/s时，不同的剂量肝实质强化峰值差异有显著性意义（P＜0．05）。结论 正常肝脏与肝硬化肝脏的螺旋CT增强扫描的最佳剂量、注射流率应分别为1.5ml/kg、2.5ml/s和2.0ml/kg、3.0ml/s。其主动脉、门静脉及肝实质达到峰值的时间分别为：28s、52s、73s和31s、68s、77s。     

Renal contrast radiography study in hypertensive patients: comparison of the nephrotoxicity of ionic and non-ionic contrast media

The results of a study carried out on 32 patients with arterial hypertension about nephrotoxic effect obtained with a new non-ionic contrast agent have been reported. The diagnostic approach was based on the determination of the urinary excretion of two characteristic enzymes of the proximal tubule-epithelial cells (alfa-glycosidase and gamma-glutamil-transferase) and of a microprotein (beta-2-microglobulin) filtered by glomeruli and readsorbed and catalized by epithelial cells. The method used show an increased sensitivity and reliability in the early recognition of a kidney damage as well as in the control of anatomic and functional changes, in comparison with the classic parameters (azotemia, creatininemia). The results show a significantly lower enzymuric and microproteinuric level using non-ionic contrast media, also, in the patients at relatively higher risk of kidney damage. This results should be interpreted in favour to a lower potential nephrotoxicity of non-ionic contrast media and their elective use in the patients with a higher risk of kidney damage.     

Undesirable side effects of contrast media during i.v. DSA--a comparison of 2 nonionic contrast media

For the first time a controlled double-blind study was performed to compare side effects and complications of i.v. DSA with central venous application of iopamidol and iopromide. 200 consecutive patients 15-85 years of age were studied. The randomisation brought up two homogeneously structured groups of 100 patients each. Using a given protocol, 66% of the patients were classified as high-risk patients. Side-effects and complications were registered by an extensive, standardised protocol. In 71 (35.5%) of 200 patients contrast-media related side effects and complications were noted. 37 reactions in 24 patients (9 iopamidol, 15 iopromide group) were classified as clinically relevant. In four patients (4%) of each group a drug therapy was initiated. Contrast-media related reactions occurred with delay in 5.5% of initially symptom-free patients. In no case intensive care or hospital admission became necessary. There were no significant differences between the two non-ionic contrast media in the incidence of side effects and complications. Both substances were well tolerated in i.v. DSA. In the total population patients with diseases known as auto-immune diseases and prior drug reactions demonstrated clinically relevant reactions significantly more often.