Intravoxel incoherent motion magnetic resonance imaging: basic principles and clinical applications

Abstract

The purpose of this article was to show basic principles, acquisition, advantages, disadvantages, and clinical applications of intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI). IVIM MRI as a method was introduced in the late 1980s, but recently it started attracting more interest thanks to its applications in many fields, particularly in oncology and neuroradiology. This imaging technique has been developed with the objective of obtaining not only a functional analysis of different organs but also different types of lesions. Among many accessible tools in diagnostic imaging, IVIM MRI aroused the interest of many researchers in terms of studying its applicability in the evaluation of abdominal organs and diseases. The major conclusion of this article is that IVIM MRI seems to be a very auspicious method to investigate the human body, and that nowadays the most promising clinical application for IVIM perfusion MRI is oncology. However, due to lack of standardisation of image acquisition and analysis, further studies are needed to validate this method in clinical practice.

Echo time dependence of biexponential and triexponential intravoxel incoherent motion parameters in the liver

“…1 IVIM imaging has proved useful for detecting and staging various pathologies in many parts of the human body, such as the brain and abdominal organs. 2 In the biexponential IVIM model, the signal decay as a function of the diffusion weighting b is described by a biexponential function, representing the summed signal of perfusion and diffusion compartments: S 0 denotes the unweighted signal strength, f the perfusion signal fraction, D the tissue diffusion coefficient, and D * the pseudodiffusion coefficient.…”

Comparison of the pre-treatment functional MRI metrics’ efficacy in predicting Locoregionally advanced nasopharyngeal carcinoma response to induction chemotherapy

“…The assumption of the IVIM model was based on the translation movements at voxel levels. IVIM signal attenuation is the sum of the tissue and blood component, taking the shape of biexponential decay [ 18 ]: S i /S 0 = (1- f ) × exp. (−b × D slow ) + exp.…”

“…S i means the signal intensity (SI) with diffusion gradient b i , S 0 represented SI with the diffusion gradient was 0. D slow means the true diffusion representing pure molecular diffusion (mm 2 /s), while D fast represents pseudo diffusion coefficient as reflected by perfusion relative diffusion or incoherent microcirculation (mm 2 /s), PF acted as fractional perfusion related to microcirculation [ 18 ].…”

“…Previous studies have suggested that DKI can be used to evaluate curative effect of IC in malignancies [ 9 – 12 , 15 , 16 ]. Intravoxel incoherent motion (IVIM) diffusion weighted model, using multiple b values and bi-exponential fitting equation, can quantify and discriminate pure water molecular diffusion and microcirculatory perfusion of the tissue [ 17 , 18 ]. Several studies have investigated potential value of the parameters derived from IVIM in assessing and predicting its radiotherapy or chemotherapy response [ 8 , 10 , 19 – 21 ].…”

Desenvolvimento e implementação de métodos de processamento de imagens por RM para obtenção de parâmetros relacionados à perfusão e à difusão

“…As neuroimagens são muito exploradas com a técnica de IVIM. 99 O cérebro, particularmente, é de difícil análise sob a técnica IVIM pelo fato de a vascularização neste órgão ser muito baixa em relação a outros órgãos; no cérebro, o f varia em torno de 5 % para um tecido normal 100 ; isto faz com que a SNR tenda a ser baixa. Com isso, o sinal de perfusão é mais difícil de se detectar e os valores pequenos de b devem estar presentes em boa quantidade e distribuição.…”