Clinical: vascular (arterial incl. cardiac, venous incl. CT)

2.1 Which concentrations and injection protocols do we recommend for CT and CTA?
Several fairly recent publications on MDCT/CTA actually conclude quite favourably for OMNIPAQUE. Suzuki [7] showed that image quality with OMNIPAQUE 300 mgI/ml is as good as with iopamidol 370 mgI/ml at a total dose of 600 mgI/kg in CT of the aorta, portal vein and liver parenchyma, except for the portal vein in late arterial phase.

Awai [8] did a similar study comparing OMNIPAQUE, 300 vs. 350 mgI/ml in abdominal CT at 3.6 and 4.0 ml/s, resp. He concluded that when dose was adjusted to body weight, rapid injection of OMNIPAQUE 300 mgI/ml was more effective for CT of hepatocellularcarcinoma than OMNIPAQUE 350 mgI/ml. Since no saline chaser was used, approximately 30 ml CM remained in the “dead space” in the injected vein. Because of the smaller volume of OMNIPAQUE 350 mgI/ml, 30 ml lost would constitute a bigger part of the total CM dose. Thus this study supports the use of a saline chaser.

Maruyama [9] used OMNIPAQUE 350 mgI/ml, 90 ml at 4 ml/s for cardiac CTA, comparing accuracy vs. conventional cardiac catheter angiography. Sensitivity, specificity, and accuracy of the studied segments by MDCT-CA were 90%, 99.1%, and 98.1%, respectively.

Raff [10] also compared diagnostic accuracy of coronary 64-slice CTA in 70 patients vs. conventional coronary angiography. OMNIPAQUE 350 mgI/ml 100 ml at 5 ml/s (+ 40 ml NaCl) was used in all patients. This study showed that 64-slice MSCT consistently provides high-quality noninvasive coronary arteriograms accurately delineating presence or absence of lesions in the entire coronary tree in a broad spectrum of patients, including those with relatively high heart rates and obesity.

Finally MDCT/CTA is developing so quickly, that what is good practice today, may not be tomorrow.