Noise dependency in vascular parameters from combined gradient-echo and spin-echo DSC MRI.

Area of Science:

• Neuroimaging
• Medical Physics
• Radiology

Background:

• Dynamic susceptibility contrast (DSC) imaging is crucial for assessing cerebral blood volume (CBV).
• DSC techniques can estimate vessel size index (VSI) and vortex area, reflecting vessel architecture.
• The impact of noise, specifically contrast-to-noise ratio (CNR), on these DSC-derived parameters is not well understood.

Purpose of the Study:

• To investigate how contrast-to-noise ratio (CNR) affects the accuracy of cerebral blood volume (CBV), vessel size index (VSI), and vortex area estimations in DSC imaging.
• To determine the noise-sensitivity of these DSC parameters using both simulations and clinical data.

Main Methods:

• Simulations were performed to generate DSC signals with varying CNR levels.
• DSC data from 59 brain cancer patients acquired on two 3 T-scanners were analyzed to obtain CNR and relative parameter maps.
• Noise-sensitivity was assessed by correlating CNR with parameter estimations.

Main Results:

• Simulations revealed that low CNR leads to overestimation of CBV and underestimation of VSI and vortex area.
• Vortex area demonstrated higher noise-sensitivity compared to CBV and VSI.
• Clinical data corroborated simulation findings, indicating CNR < 4 results in unreliable measurements.

Conclusions:

• CNR significantly impacts DSC-derived parameters, with potential to alter clinical interpretations of DSC-MRI.
• Excluding low-CNR voxels can substantially change parameter distributions in tumor regions.
• CNR should be considered in clinical decision-making for DSC imaging to ensure reliable results.