Some of the views expressed in the following notes on newly approved products should be regarded as tentative, as there may have been limited published data and little experience in Australia of their safety or efficacy. However, the Editorial Executive Committee believes that comments made in good faith at an early stage may still be of value. As a result of fuller experience, initial comments may need to be modified. The Committee is prepared to do this. Before new drugs are prescribed, the Committee believes it is important that full information is obtained either from the manufacturer's approved product information, a drug information centre or some other appropriate source.
Primovist (Schering)
pre-filled syringes containing 10 mL
Approved indication: liver imaging
Magnetic resonance imaging (MRI) can be enhanced by the use of contrast agents. Gadoxetate is a gadolinium containing contrast agent which can be used in the detection of focal hepatic lesions.
After intravenous injection gadoxetate concentrates in the liver and kidneys. Uptake into normal hepatocytes is more likely than into abnormal areas such as metastases. As gadoxetate is eliminated in the bile, as well as in the urine, it may have a role in imaging the biliary system.
One of the clinical trials of gadoxetate involved 131 patients with known or suspected lesions in the liver. These patients had MRI before and 20 minutes after an injection of gadoxetate. Using the contrast agent increased the number of lesions identified by the researchers and by external radiological reviewers. Although the sensitivity of MRI was increased, the improvement was not statistically significant for all the radiologists.1
In other studies adding gadoxetate has increased the proportion of correctly characterised lesions from 81% to 88%. The combination of precontrast, dynamic and postcontrast MRI correctly characterises 89% of lesions compared to 80% with contrast-enhanced computed tomography (CT).
The main adverse effects of gadoxetate are headache, nausea, vasodilatation, back pain and abdominal pain. Anaphylactoid reactions can occur and gadoxetate may prolong the QTc interval on the ECG.
Other hepatobiliary contrast agents are available overseas, but the dilemma is whether the advantages of contrast-enhanced MRI are sufficiently superior to MRI and CT to make a difference to the patient's management.
Reference
1. Huppertz A, Balzer T, Blakeborough A, Breuer J, Giovagnoni A, Heinz-Peer G, et al. Improved detection of focal liver lesions at MR imaging: multi center comparison of gadoxetic acid-enhanced MR images with intraoperative findings. Radiology 2004;230:266-75
The T-score ( 
) is explained in 'Two-way
transparency', Aust Prescr 2005;28:103.
