GADOVIST

Indications

• MRI of the central nervous system
• MRI of the spine
• MRI of the cardiovascular system
• MRI of the abdomen and pelvis
• MRI of joints and musculoskeletal structures

Dosage

Children: Refer to the BNF for Children for detailed dosing information based on the child's weight and clinical indication.

Adults: The usual dose for adults is between 0.1 and 0.3 mmol/kg body weight, administered as an intravenous injection. The specific volume and concentration depend on the protocol for the MRI examination.

Mechanism of action

In MRI, gadobutrol enhances the visualization of tissues by shortening the T1 and T2 relaxation times of protons. This effect varies based on factors such as the concentration of gadobutrol in the tissue, the strength of the MRI system's magnetic field, and the relative ratios of longitudinal and transverse relaxation times. The T1 shortening is particularly sensitive in T1-weighted sequences, while T2*-weighted sequences can show signal decreases due to local magnetic field inhomogeneities caused by gadolinium.

Pharmacodynamics

Gadobutrol significantly shortens relaxation times even at low concentrations. At a pH of 7, 37°C, and a magnetic field strength of 1.5 T, the relaxivity (r1) is 5.2 L/(mmol·sec) for T1 and 6.1 L/(mmol·sec) for T2. These relaxivities demonstrate minimal dependence on the magnetic field strength, making gadobutrol effective across various imaging settings.

Pharmacokinetics

Gadobutrol is primarily eliminated from the body via the kidneys. It has a high plasma protein binding rate, which influences its distribution in the body. The contrast agent is excreted unchanged in the urine, and its pharmacokinetic profile is characterized by a rapid distribution phase followed by a slower elimination phase.

Adverse effects

• Nausea
• Headache
• Dizziness
• Injection site reactions
• Hypersensitivity reactions

Precautions

• Monitor renal function prior to administration
• Use with caution in patients with a history of allergic reactions to gadolinium-based agents
• Ensure adequate hydration before and after administration

Pregnancy

Use only if the potential benefit justifies the potential risk to the fetus. Safety has not been established.

Breast-feeding

It is not known whether gadobutrol is excreted in human milk. Caution should be exercised when administering to a nursing woman.

Storage

Store at 20°C to 25°C (68°F to 77°F). Protect from light. Do not freeze.

Formulations

• Gadobutrol 1.0 mmol/mL solution for injection

Mechanism of action

In MRI, visualization of normal and pathological tissue depends in part on variations in the radiofrequency signal intensity that occur with differences in proton density, the spin-lattice or longitudinal relaxation times (T1), and the spin-spin or transverse relaxation time (T2). When placed in a magnetic field, gadobutrol shortens the T1 and T2 relaxation times. The extent of decrease of T1 and T2 relaxation times, and therefore the amount of signal enhancement obtained from gadobutrol, is based upon several factors including the concentration of gadobutrol in the tissue, the field strength of the MRI system, and the relative ratio of the longitudinal and transverse relaxation times. At the recommended dose, the T1 shortening effect is observed with the greatest sensitivity in T1-weighted magnetic resonance sequences. In T2*-weighted sequences, the induction of local magnetic field inhomogeneities by the large magnetic moment of gadolinium and at high concentrations (during bolus injection) leads to a signal decrease.

Pharmacodynamics

Gadobutrol leads to distinct shortenings of relaxation times even in low concentrations. At pH 7, 37°C and 1.5 T, the relaxivity (r1) - determined from the influence on the relaxation times (T1) of protons in plasma - is 5.2 L/(mmol·sec) and the relaxivity (r2) - determined from the influence on the relaxation times (T2) - is 6.1 L/(mmol·sec). These relaxivities display only slight dependence on the strength of the magnetic field.