Is it better to use a higher concentration contrast agent for cardiac CT?
“We administered 80-100 mL of contrast material [Group 1: Iomeprol, Iomeron 400 mgI/mL, Bracco (Iodine burden = 32-40 grI); Group 2: Iodixanol, Visipaque 320 mgI/mL, GE Healthcare (Iodine burden = 25.6-32 grI)] at an injection rate of 5-6 mL/s [depending on the quality of the venous access; Iodine Delivery Rate (IDR): Group 1 = 2.0-2.4 mgI/s and Group 2 = 1.6-1.92 mgI/s] with an automatic injector (Stellant, MedRad, Pittsburgh, PA, USA) attached to an 18- to 20-gauge needle cannula inserted in an antecubital vein.” Plaque imaging with CT angiography: Effect of intravascular attenuation on plaque type classification Maffei E et al. World J Radiol 2012 Jun 28;4(6):265-272
“High intra-vascular attenuation modified significantly the attenuation of non-calcified coronary plaques. As a result, the detection of fibrous vs lipid rich plaques was significantly affected. Image quality was not significantly affected by different settings (i.e., CT scanner and contrast medium used). S/N was significantly better in the Group using lower iodine concentration and with lower intra-vascular attenuation.” Plaque imaging with CT angiography: Effect of intravascular attenuation on plaque type classification Maffei E et al. World J Radiol 2012 Jun 28;4(6):265-272
“ Higher intra-vascular attenuation modifies significantly the attenuation of non-calcified coronary plaques. This results in a more difficult characterization between lipid rich vs fibrous type.” Plaque imaging with CT angiography: Effect of intravascular attenuation on plaque type classification Maffei E et al. World J Radiol 2012 Jun 28;4(6):265-272
OBJECTIVES: To compare vascular and parenchymal contrast enhancement in multidetector computed tomography of the liver using two contrast media with different iodine concentration (Iodixanol 320mgI/mL and Iomeprol 400mgI/mL) and similar viscosity, using fixed total iodine volume (40gI) and iodine delivery rate (1.6gI/s). CONCLUSIONS: Iodixanol 320 and Iomeprol 400 injected at the same iodine delivery rate (1.6gI/s) and total iodine load (40gI) did not provide statistically significant differences in liver parenchymal and vascular contrast enhancement. High concentration (400mgl/mL) versus low concentration (320 mgl/mL) iodinated contrast media in multi detector computed tomography of the liver: A randomized single center, non inferiority study Rengo M et al. Eur J Radiol 2012 June 8 (Epub ahead of print)
“ The three monomeric agents studied (iopamidol 300, iopromide 300, ioxehol 300) and the one dimeric agent (iodixanol 320) were equivalent in terms of lack of a significant effect on measured GFR when administered to patients with normal GFR.” Glomerular Filtration Rate in Evaluation of the Effect of Iodinated Contrast Media on Renal Function Becker J et al. AJR 2013; 200:822-826
“ Given the remaining uncertainties about the real incidence of contrast medium-induced nephropathy, how should we practice? It is our recommendation that we be more liberal in our policies in regard to contrast medium administration.” Quantitating Contrast Medium-induced Nephropathy: Controlling the Controls Newhouse JH, RoyChoudhury Radiology 2013; 267:4-8
Omnipaque-350 vs. Visipaque-320
- Both work very well for all CT Angiographic studies - Despite differences in iodine concentration the opacification of vessels which determine in great part the success of CT angiography are equivalent (Pannu HP, Fishman EK WIP)
"Most respondents (75%) perform CT angiography in pregnant patients suspected of having pulmonary embolism, but their policies and practices vary considerably."
Pulmomary Embolism in Pregnant Patients: A Survey of Practices and Policies for CT Pulmonary Angiography Schuster ME et al. AJR 2003; 181:1495-1498
When is Visapaque always used?
- Borderline renal function - Older patients especially if diabetic - Patients who already received one contrast injection in the preceding 24-36 hours - All patients premedicated due to prior contrast reaction - All pulmonary embolism studies - All coronary angiography studies
What about saline bolus chasing?
- Improved use of contrast volume (contrast in IV line and periperal veins (10-15 cc) - Ideal in coronary angiography studies to wash dense contrast from the right side of the heart - Ideal in patients with borderline renal function to make better use of contrast - Decreased volume of contrast needed
"Using a saline flush after the contrast material bolus in abdominal CT allows an iodine dose reduction of approximately 6 g, or 17%, without impairing mean parenchymal and vascular enhancement and a cost reduction of $7.30 per patient."
Abdominal Multidetector Row Computed Tomography: Reduction of Cost and Contrast Material Dose Using Saline Flush Schoellnast H et al. J Comput Assist Tomogr 2003;27:847-853
"Using 100 ml of contrast material and a saline chaser did not result in a meaningful difference in liver parenchyma attenuation or lesion conspicuity compared with using 150 ml of contrast medium alone.Routine use of a chaser for abdominal CT may yield cost savings and a decreased risk of contrast nephropathy."
Using a Saline Chaser to Decrease Contrast Media in Abdominal CT Dorio PJ et al. AJR 2003; 180:929-934