Related Experiment Videos
Perfusion-related parameters in intravoxel incoherent motion MR imaging compared with CBV and CBF measured by dynamic
R Wirestam1, M Borg, S Brockstedt
1Department of Radiation Physics, University Hospital, Lund, Sweden.
Objective:
Perfusion-related parameters obtained by intravoxel incoherent motion (IVIM) MR imaging (MRI) were compared with cerebral blood volume and flow (CBV and CBF), retrieved by dynamic susceptibility-contrast (DSC) MRI.
Material And Methods:
Twenty-eight volunteers (average age 68.5 years) were investigated. Spin-echo echo-planar imaging with IVIM-encoding gradients was employed (36 different b values, 0-1200 s/mm2). The perfusion fraction and the pseudo-diffusion coefficient were calculated for regions in thalamus gray matter and frontal white matter, using asymptotic and full fitting. In DSC-MRI, a Gd-DTPA-BMA contrast-agent bolus was monitored using simultaneous-dual FLASH. Deconvolution of the measured tissue concentration-versus-time curve with an arterial input function from the carotid artery was applied, and maps of CBV and CBF were calculated.
Results:
The correlation between the perfusion fraction and CBV was r=0.56 (p<0.0000006) using asymptotic fitting, and r=0.35 (p<0.0004) when full fitting was applied. Average CBF was 41.5 ml/(min 100 g), to be compared with the IVIM-based value of 63.6 ml/(min 100 g), obtained from the median value of the pseudo-diffusion coefficient in combination with assumptions about capillary network structure.
Conclusion:
The IVIM concept provided results that agreed reasonably with conventional CBV and CBF. The non-linear fitting to noisy signal data was problematic, in accordance with previously presented simulations.
Insights
Intravoxel Incoherent Motion (IVIM) MRI offers a promising alternative for measuring brain perfusion, showing reasonable agreement with traditional dynamic susceptibility-contrast (DSC) MRI methods for cerebral blood volume and flow.
Area of Science:
- Radiology
- Neuroimaging
- Medical Physics
Background:
- Intravoxel Incoherent Motion (IVIM) Magnetic Resonance Imaging (MRI) provides perfusion-related parameters.
- Dynamic Susceptibility-Contrast (DSC) MRI is a conventional method for assessing cerebral blood volume (CBV) and cerebral blood flow (CBF).
- Comparing these techniques is crucial for validating novel imaging approaches.
Purpose of the Study:
- To compare perfusion parameters derived from IVIM MRI with established CBV and CBF values obtained from DSC MRI.
- To evaluate the correlation between IVIM-derived perfusion fraction and DSC-derived CBV.
- To assess the agreement of IVIM-based CBF estimations with DSC-based CBF measurements.
Main Methods:
- Twenty-eight elderly volunteers underwent both IVIM and DSC MRI.
- IVIM imaging utilized spin-echo echo-planar imaging with multiple b values (0-1200 s/mm2) to calculate perfusion fraction and pseudo-diffusion coefficient.
- DSC MRI involved a contrast agent bolus and deconvolution techniques to generate CBV and CBF maps.
Main Results:
- A moderate positive correlation was found between the IVIM perfusion fraction and DSC-derived CBV (r=0.56 with asymptotic fitting, r=0.35 with full fitting).
- IVIM-based estimation of CBF (63.6 ml/(min 100 g)) was higher than the average DSC-derived CBF (41.5 ml/(min 100 g)).
- Non-linear fitting of noisy IVIM signal data presented challenges.
Conclusions:
- IVIM MRI provides perfusion results that reasonably correlate with conventional CBV and CBF measurements.
- The study highlights potential challenges in IVIM data analysis due to noisy signals and fitting complexities.
- IVIM MRI shows promise as a non-contrast alternative for brain perfusion assessment.