IV Contrast

Are there any contrast volume limitations for the use of IV contrast?

Indeed there is and here are some rules for Omnipaque and Visipaque courtesy of Rich Vitti MD from GE Healthcare. The recommended doses of Omnipaque™1 and Visipaque™2 for CT body imaging are: Omnipaque 300 50ml to 200ml (15gI to 60gI) Omnipaque 350 60ml to 100ml (21gI to 55gI) Visipaque 270 100ml to 150ml (27gI to 40gI) Visipaque 320 100ml to 150ml (32gI to 48gI) The maximum total doses of iodine are as follows: Omnipaque 87.5gI (87500mgI) with a clearance of 90% of injected dose within the first 24hrs Visipaque 80gI (80000mgI) with a clearance of 97% of injected dose within the first 24hrs

GE Healthcare does not recommend the use of its products outside of the package labeling. Please refer to the package insert for full prescribing information.

Please keep in mind that the doses described below may not have been approved or cleared by the FDA.

Traditionally contrast dose for adult body CT is given in ranges of 50ml – 200ml, depending on procedure (hepatic, renal…) and iodine concentration (270mgI/ml to 400 mgI/ml). With increasing awareness of CIN and radiation dose, the trend has started to shift toward contrast dose by body weight. Some device manufacturers like Medrad (P3T) have introduced power injectors that follow a dose by weight protocol. There are a few studies published on weight-based dose for adults. Below are several examples.

Yanaga gives recommendations for specific exams:

• Hypervascular HCC
• Injection duration rate 30 sec
• Total iodine dose of 525mg or more per kilogram of patient body weight
• CTA using estimated lean patient body weight instead of total body weight
• Pancreatic & hepatic enhancement tailored to patient weight with a fixed injection rate

Ichikawa recommends the following for hepatic imaging:

• Scan duration throughout whole liver with a MDCT scanner: 10 sec;
• Dose and concentration of contrast material: 2 mL/kg with 300 mg I/mL;
• Injection duration: fixed, 30 sec (corresponds to 4 mL/s as fixed injection rate);
• Injection rate: variable (depends on patients’ body weight);
• Scan start time after the beginning of injection of contrast material for each phase:
  • Hepatic arterial-dominant phase (HAP): 40 sec;
  • Hepatic parenchymal phase (HPP): 55 sec;
  • Delayed phase (DP): 3 min;

Exceptional patients: with severe cardiac dysfunction/abnormal circulation (we recommend a use of double arterial-phase imaging or any bolus tracking techniques, such as manual mini-bolus or automatically computer-assisted bolus tracking techniques).

Megibow7 recommends the following for abdominal CT:

• Weight-based dose of 1.5ml/kg for most patients

References:

1. Omnipaque™ prescribing information.

2. Visipaque™ prescribing information.

3. Yanaga Y, Awai K, Nakaura T, Namimoto T, et al. Optimal contrast dose for depiction of hypervascular hepatocellular carcinoma at dynamic CT using 64-MDCT. AJR. 2008;190:1003-1009.

4. Yanaga Y, Awai K, Nakaura T, Oda S, et al. Effect of contrast injection protocols with dose adjusted to the estimated lean patient body weight on aortic enhancement at CT angiography. AJR. 2009;192:1071-1078.

5. Yanaga Y, Awai K, Nakayama Y, Nakaura T, et al. Páncreas: Patient body weight-tailored contrast material injection protocol versus fixed dose protocol at dynamic CT. Radiol. 2007;245:475-482.

6. Ichikawa T, Erturk SM, Araki T. Multiphasic contrast-enhanced multidetector-row CT of liver: Contrast-enhancement theory and practical scan protocol with a combination of fixed injection duration and patients’ body-weight-tailored dose of contrast material. EJR. 2006;58:165-176.

7. Megibow AJ, Jacob G, Heiken JP, Paulson EK, et al. Quantitative and qualitative evaluation of volume of low osmolality contrast medium needed for routine helical abdominal CT. AJR. 2001;178:583-589.  

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