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Study: Additional Brain Metastases identified in patients after MRI with a higher relaxivity contrast agent

Improved MR imaging performance with Gadovist® has been reported in an intraindividual comparison with gadopentetate dimeglumine for the detection of brain metastases.1 Differences between these agents include the higher relaxivity and gadolinium concentration of Gadovist®.2

In this study, 27 patients with at least one brain metastasis were examined twice with contrast-enhanced MRI using Gadovist® at 0.1 mL/kg and gadopentetate dimeglumine at 0.2 mL/kg (identical gadolinium dosage of 0.1 mmol/kg bodyweight). The interval between the two exams was 18 hours and the order of contrast agents administered was randomized.

The images were evaluated by two neuroradiologists who were blinded to the contrast agents used in each examination. Images were evaluated quantitatively in terms of the total number of lesions detected and qualitatively in terms of the lesion conspicuity observed in a side-by-side comparison of the examinations.

Improved performance with Gadovist® versus gadopentetate dimeglumine was reported for 12 of the 27 patients included in the study. In 10 of these patients, the improved performance was due to improved lesion conspicuity with Gadovist®. Furthermore, in 2 patients, additional lesions were detected only with Gadovist® (Figure 1). The examinations were equivalent between gadovist and gadopentetate dimeglumine in the remaining 15 patients in the study.

Figure 1. In a patient with lung cancer, Gadovist®-enhanced MRI (left) revealed one more lesion in the thalamus (arrow), than the gadopentetate dimeglumine exam (right)

The improved lesion conspicuity and detection of additional lesions with Gadovist® may be related to the higher relaxivity and gadolinium concentration of Gadovist®. While gadopentetate dimeglumine is a linear gadolinium based contrast agent (GBCAs), it has a similar relaxivity compared to macrocyclic GBCAs other than Gadovist® (Table 1).

Table 1. Properties of gadopentetate dimeglumine versus macrocyclic gadolinium based contrast

agents †

Product Structure Relaxivity at 1.5 T (L mmol-1 s-1)2 Relaxivity at 3 T

(L mmol-1 s-1)2

 Concentration (mmol/mL)
gadopentetate dimeglumine Linear 4.1 3.7 0.5
gadobutrol/Gadovist® Macrocyclic 5.2 5.0 1.0
gadoteridol Macrocyclic 4.1 3.7 0.5
gadoterate meglumine Macrocyclic 3.6 3.5 0.5

† relaxivities measured in plasma at 37˚C (values in L mmol-1 s-1)

The authors discuss that although there are too few patients in the study to draw definite conclusions, the benefits of Gadovist® (gadobutrol) seem clear. Even the detection of one additional lesion can have major clinical implications for patient management. They conclude “the present study suggests that gadobutrol is advantageous compared with gadopentetate dimeglumine for the visualization of cerebral metastases, with particular benefit for improving the conspicuity of detected lesions”.

 

References

  1. Anzalone et al. Acta Radiol 2009; 50(8):993-40
  2. Rohrer et al. Invest Radiol 2005; 40(11):715-24

 

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