Contrast media recommendations

Recommendation Isotope imaging of the thyroid should be avoided for 2 months after iodinated contrast medium injection. 

The contrast load may compound renal damage, common in HF patients, with consequent further fluid retention and worsening HF A number of adjunctive treatments are currently recommended in the renal patient but none guarantee renal protection (82). The volume of contrast medium during intervention should be minimized and hypotension should be avoided. 

Iso-osmolar or low-osmolar contrast medium is recommended, and it appears to be associated with a lower renal complication rate. Serum creatinine level should be measured 24 to 48 hours after the administration of the contrast medium. Nonsteroidal anti-inflammatory drugs and... 

In addition to using a small dose of low-osmolar non-ionic contrast medium and offering hydration, some authors have recommended the use of calcium channel blockers in patients at high risk of contrast nephrotoxicity. However, the effectiveness of this class of drugs in preventing contrast nephrotoxicity has not been consistently... 

Theophylline, a non-selective adenosine receptor antagonist, has also been recommended, since adenosine has been suggested to be an important mediator of contrast-induced nephrotoxicity. Patients undergoing coronary angiography with the high-osmolar contrast medium dia-trizoate (iodine 370 mg/ml) were randomized to receive either theophylline (200 mg bd orally 24 hours before and for 48 hours after coronary angiography, n = 35, mean age 54 years, mean dose of contrast medium 78 ml) or placebo (n = 35, mean age 52 years, mean dose of contrast medium 80 ml) (197). The glomerular filtration rate... 

The dilution is the unique factor which can be taken in consideration by the operator. Since the number of microspheres per millimeter of sediment is very high (about one million for small calibers), an adapted dilution has to be used. Without appropriate dilution, each 0.1 ml of sediment contains thousands of microspheres. The usual dilution recommended for clinical practice for microspheres is xlO, for instance 2 ml of microspheres in a 20-ml solution (contrast material and saline). One may suggest different optimal dilutions for larger sizes, i.e. over 600 pm and for smaller microspheres. Given the number of microspheres in a vial/syringe of 100 pm, higher dilutions (xlOO or even xlOOO) may be appropriate (Fig. 10.6.3). This has to be balanced with the acceptable amount of iodinated contrast medium injected. 

For oral and rectal contrast,radiopaque substances are available or water or a mixture of water and mannitol can be used. The latter should be used only when there is good intravenous enhancement. Only nonionic contrast media should be used for intravenous contrast. For routine clinical administration, a total dose of 90-120 ml of a contrast medium with a concentration of 300-370 mg injected at a rate of 2-3 ml/s is recommended. 

There is also no agreement on opacification of the vagina in the literature. Usually ultrasound gel is instilled, which is an easy to handle and well tolerated contrast medium. Delineation of the entire vagina and especially of the posterior fornix and posterior wall is always achieved [24,30]. In addition, during Valsalva s maneuver the gel in the vagina is emptied passively and thus the movement of the organ itself is not impeded [21]. In this regard rubber tubes are not a recommended alternative [18]. 

The challenge for spinal artery CTA is to provide sufficient arterial enhancement but to scan before arrival of contrast medium in the venous system. An ROI of the bolus tracking system placed in the ascending aorta might be affected by inflow artifacts of the SVC and may result in a mistimed early scan. Therefore, placement of the ROI in the aortic arch or descending aorta is recommended. In the presence of aortic dissection, caution should be taken that the ROI is not too big or positioned in the false lumen or across the dissection membrane, respectively. In these cases, manual start of the scan should be considered. The Hounsfield unit threshold should be around 100 HU above baseline. Scan start is usually delayed by time for table movement (<3 s), which is usually right above the origin of the vertebral arteries. An additional scan delay of 3 s is recommended for scanners with equal to or more than 16 rows and rotation time equal or less than 0.4 s. Hounsfield unit values of attenuated blood in the thoracic aorta should never be lower than within the pulmonary trunk. 

Nonionic iodinated contrast media (2ml/kg) are preferred because they have been shown to decrease the incidence of minor events (K ataya m a et al. 1990). Diluted barium sulfate can be administered per os (the preferred drink of the child is recommended for dilution) or by enema to beacon the digestive tract. A child with a proven history of a severe accident with iodinated contrast medium should be referred to an allergist and an anesthesiologist who will make medical decisions about any further injection. In case a new injection is mandatory, a different contrast medium... 

Iodized Oil Iodine in poppy seed oil-lipiodol is extensively used in radiology as a radio-contrast medium to demonstrate holes (cavities) in the lung. Available both by injection (lipiodol) and by mouth (oriodol) for the instant correction of iodine deficiency Iodized Salt Salt to which potassium iodate or potassium iodide has been added at a recommended level of 20—40 milligrams of iodine per kilogram of salt Kiwanis International A World Service Group including more than 10,000 clubs and over 500,000 members based in the USA... 

There is no completely reliable method of preventing contrast media reactions but there may be a case for some form of prophylaxis in patients who have previously had reactions to contrast media. Schatz et al. (25 ) recommend the use of prophylactic antihistamine for these cases. However, steroid therapy would appear to be more rational. Zweiman and Hildreth (26 ) used large doses of steroids in 8 patients who had previously had anaphylactic phenomena such as wheezing or shock foilowing a contrast medium injection. In these cases, they administered 150 mg of prednisone during the 18 hours prior to the repeat contrast medium examination and a further 75 mg of prednisone in the 12 hours after the examination. A mild reaction occurred in one patient and none in the other 7. While this was an uncontroUed trial, it compares favourably with the normally expected figure of 30—35% recurrence. In a subsequent... 

Novobiocin also causes chaining in Streptococcus faecium [23], although this effect is not produced in all cocci [13]. The induction of spheroplasts in Escherichia coli by novobiocin has also been reported [24] and, in fact, the antibiotic has been recommended for preparing spheroplasts in Gramnegative bacteria [25]. In contrast, however, it has been shown by various workers [26-28] that novobiocin does not induce spheroplasts in Serratia marcescens or in various strains of E. coli and [28] that it may even prevent spheroplast induction caused by benzylpenicillin in hypertonic medium (Figure 2.1). 

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