Gadolinium retention in the brain

Case contributed by Prof Alan Coulthard

Presentation

Diagnosed with neurosarcoidosis 6 years earlier.

Patient Data

Age: 55 years
Gender: Female

T1 weighted non-contrast axial series post right frontal craniotomy for biopsy of neurosarcoid 6 years ago. There are blood products at the biopsy site. Note the posterior fossa appearances for comparison with the next series.

Follow up non-contrast study 6 years later. The patient has had 9 contrast-enhanced MRI studies in the interim. 

Note the high T1 signal in the dentate nuclei and to a lesser extent the basal ganglia

Case Discussion

Received wisdom until recently was that gadolinium contrast agents were excreted by first pass through the kidneys. Gadolinium is toxic but is considered safe as it is chelated to molecules such as DTPA. A study published recently compared postmortem specimens in 13 patients who had undergone multiple MRI studies with gadolinium contrast agents and 10 patients who had undergone multiple MRI scans without contrast administration. All patients had a normal renal function. The dentate nuclei, pons, globus pallidus and thalami were studied. The study group had tissue gadolinium concentrations which were dose related to the number of contrast administrations. The control group had no gadolinium within the neural tissue. 

The molecular structure of the contrast agent plays a role in gadolinium retention. There are two structurally-distinct classes of gadolinium-based contrast agents (GBCA) - linear and macrocyclic. With the macrocyclic structure, gadolinium is bound more tightly to the chelating agent and is less likely to be released as free gadolinium. Gadolinium is more 'exposed' in the linear structure.

A study comparing dentate nucleus signal intensity after previous GBCA administration in patients who had received linear GBCAs compared with patients who had received macrocyclic GBCAs show no association between dentate signal hyperintensity and macrocyclic GBCA, but a highly significant association in patients who had received linear GBCAs.

The most commonly used linear GBCA is MagnevistTM. An example of a macrocyclic GBCA is GadovistTM

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Case information

rID: 38904
Published: 11th Aug 2015
Last edited: 23rd Apr 2018
Inclusion in quiz mode: Included

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