Manganese (Mn2+)-enhanced MRI (MEMRI) is a valuable imaging tool to study brain structure and function in normal and diseased small animals. The brain retention of Mn2+ is relatively long with a half-life (t1/2) of 51-74 days causing a slow decline of MRI signal enhancement following Mn2+ administration. Such slow decline limits using repeated MEMRI to follow the central nervous system longitudinally in weeks or months. This is because residual Mn2+ from preceding administrations can confound the interpretation of imaging results. We investigated whether the Mn2+ enhancement decline could be accelerated thus enabling repeated MEMRI, and as a consequence broadens the utility of MEMRI tests. New methodsWe investigated whether N-acetyl-para-aminosalicylic acid (AcPAS), a chelator of Mn2+, could affect the decline of Mn2+ induced MRI enhancement in brain. Results and conclusionTwo-week treatment with AcPAS (200mg/kg/dose×3 daily) accelerated the decline of Mn2+ induced enhancement in MRI. In the whole brain on average the enhancement declined from 100% to 17% in AcPAS treated mice, while in PBS controls the decline is from 100% to 27%. We posit that AcPAS could enhance MEMRI utility for evaluating brain biology in small animals. Comparison with existing methodsTo the best of our knowledge, no method exists to accelerate the decline of the Mn2+ induced MRI enhancement for repeated MEMRI tests.
- Manganese enhanced MRI (MEMRI)
- N-acetylated-para-aminosalicylic acid (AcPAS)
- Repeated MEMRI
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