Prostate DCE-MRI with B1+ correction using an approximated analytical approach.

PURPOSE: To develop and evaluate a practical B1+ correction method for prostate dynamic contrast-enhanced (DCE) MRI analysis.

THEORY: We proposed a simple analytical B1+ correction method using a Taylor series approximation to the steady-state spoiled gradient echo signal equation. This approach only requires B1+ maps and uncorrected pharmacokinetic (PK) parameters as input to estimate the corrected PK parameters.

METHODS: The proposed method was evaluated using a prostate digital reference object (DRO), and 82 in vivo prostate DCE-MRI cases. The approximated analytical correction was compared with the ground truth PK parameters in simulation, and compared with the reference numerical correction in in vivo experiments, using percentage error as the metric.

RESULTS: The prostate DRO results showed that our approximated analytical approach provided residual error less than 0.4% for both Ktrans and ve , compared to the ground truth. This noise-free residual error was smaller than the noise-induced error using the reference numerical correction, which had a minimum error of 2.1+4.3% with baseline signal-to-noise ratio of 234.5. For the 82 in vivo cases, Ktrans and ve percentage error compared to the reference numerical correction method had a mean of 0.1% (95% central range of [0.0%, 0.2%]) across the prostate volume.

CONCLUSION: The approximated analytical B1+ correction method provides comparable results with less than 0.2% error within 95% central range, compared to reference numerical B1+ correction. The proposed method is a practical solution for B1+ correction in prostate DCE-MRI because of its simple implementation.