Rapid measurement of intravoxel incoherent motion (IVIM) derived perfusion fraction for clinical magnetic resonance imaging

Emma M Meeus,Hamid Dehghani,Andrew C Peet,Jan Novak

doi:10.1007/s10334-017-0656-6

Abstract

ObjectiveThis study aimed to investigate the reliability of intravoxel incoherent motion (IVIM) model derived parameters D and f and their dependence on b value distributions with a rapid three b value acquisition protocol.Materials and methodsDiffusion models for brain, kidney, and liver were assessed for bias, error, and reproducibility for the estimated IVIM parameters using b values 0 and 1000, and a b value between 200 and 900, at signal-to-noise ratios (SNR) 40, 55, and 80. Relative errors were used to estimate optimal b value distributions for each tissue scenario. Sixteen volunteers underwent brain DW-MRI, for which bias and coefficient of variation were determined in the grey matter.ResultsBias had a large influence in the estimation of D and f for the low-perfused brain model, particularly at lower b values, with the same trends being confirmed by in vivo imaging. Significant differences were demonstrated in vivo for estimation of D (P = 0.029) and f (P < 0.001) with [300,1000] and [500,1000] distributions. The effect of bias was considerably lower for the high-perfused models. The optimal b value distributions were estimated to be brain500,1000, kidney300,1000, and liver200,1000.ConclusionIVIM parameters can be estimated using a rapid DW-MRI protocol, where the optimal b value distribution depends on tissue characteristics and compromise between bias and variability.

Highlights

The acquisition of multi-b value diffusion-weighted magnetic resonance (DW-MRI) data and the bi-exponential signal decay observed in biological tissue have led to an increased number of studies using the intravoxel incoherent motion (IVIM) model [1, 2]
The model determines the fraction of signal arising from the microvascular network (f), known as perfusion fraction, which is thought to describe the vascularity of the tissue [1]
For highly perfused tissues, such as reported for cirrhotic liver [8, 9, 32] hepatocellular carcinomas [5, 33], prostate cancer [34, 35] and many of the pancreas related pathologies [12, 36, 37], our results suggest that the use of a low b value can reduce the variability in estimating the perfusion fraction

Summary

Introduction

The acquisition of multi-b value diffusion-weighted magnetic resonance (DW-MRI) data and the bi-exponential signal decay observed in biological tissue have led to an increased number of studies using the intravoxel incoherent motion (IVIM) model [1, 2]. The IVIM model can be used to investigate the underlying tissue microenvironment and is based on the simultaneous assessment of two diffusion components. These correspond to the molecular diffusion in tissue (D) and diffusion affected by perfusion in the microcapillary network, often described as pseudo-diffusion (D*). The model determines the fraction of signal arising from the microvascular network (f), known as perfusion fraction, which is thought to describe the vascularity of the tissue [1]. The use of multi-b value DW-MRI has the potential to provide a single acquisition protocol for the non-invasive assessment of diffusion and perfusion in tissue

Methods

Results

Discussion

Conclusion