MR扩散峰度成像原理及其在中枢神经系统的初步应用

通过对水分子扩散运动的测量,扩散张量成像（ＤＴＩ）可以无创地对组织结构进行评价,而扩散峰度成像（ＤＫＩ）是以DTI为基础,对生物组织内水分子扩散的非高斯分布特征进行定量分析,揭示组织结构细微改变。DKI较DTI能提供更多关于组织微观结构的信息。综述DKI的原理及其在中枢神经系统的应用,包括神经退行性疾病、创伤性脑损伤、缺血性脑卒中、胶质瘤、多发性硬化、脑发育等。     

Estimation of the orientation distribution function from diffusional kurtosis imaging

The Orientation Distribution Function (ODF) is used to describe the directionality of multimodal diffusion in regions with complex fiber architecture present in brain and other biological tissues. In this study, an approximation for the ODF of water diffusion from diffusional kurtosis imaging (DKI) is presented. DKI requires only a relatively limited number of diffusion measurements and, for the brain, b values no higher than 2500 s/mm². The DKI‐based ODF approximation is decomposed into two components representing the Gaussian and non‐Gaussian (NG) diffusion contributions, respectively. Simulations of multiple fiber configurations show that both the total and the NG‐ODF are able to resolve the orientations of the component fibers, with the NG‐ODF being the most sensitive to profiling the fibers' directions. Orientation maps obtained for in vivo brain imaging data demonstrate multiple fiber components in brain regions with complex anatomy. The results appear to be in agreement with known white matter architecture. Magn Reson Med 60:774–781, 2008. © 2008 Wiley‐Liss, Inc.     

Microstructural changes of the corticospinal tract in idiopathic normal pressure hydrocephalus: a comparison of diffusion tensor and diffusional kurtosis imaging

Introduction

The goals of this study were to examine the usefulness of diffusional kurtosis imaging (DKI) for assessing microstructural changes in the compressed corticospinal tract (CST) among patients with idiopathic normal pressure hydrocephalus (iNPH).

Methods

Eleven patients with iNPH (mean age: 73.6 years, range: 65–84), who underwent 3-T magnetic resonance imaging, including DKI before surgery, were recruited. Six age-matched, healthy subjects (mean age: 69.8 years, range: 60–75) served as the control group. DKI and diffusion tensor imaging parameters were calculated and compared between the iNPH and the control groups using tract-specific analysis of the CST at the level of the lateral ventricle.

Results

Mean diffusional kurtosis (DK) and axial diffusion kurtosis were significantly lower in iNPH patients. However, apparent diffusion coefficient, fractional anisotropy, and axial eigenvalue (λ ₁ ) were significantly higher in the iNPH group than in the control group.

Conclusions

The mechanical pressure caused by ventricular enlargement in iNPH patients might induce formation of well-aligned fiber tracts and increased fiber density in the CST, resulting in decreased DK. DKI is able to depict both the altered microstructure and water molecule movement within neural axons and intra- or extracellular space. In addition, the investigated DKI parameters provide different information about white matter relative to conventional diffusional metrics for iNPH.     

Characteristics of Diffusional Kurtosis in Chronic Ischemia of Adult Moyamoya Disease: Comparing Diffusional Kurtosis and Diffusion Tensor Imaging

BACKGROUND AND PURPOSE:Detecting microstructural changes due to chronic ischemia potentially enables early identification of patients at risk of cognitive impairment. In this study, diffusional kurtosis imaging and diffusion tensor imaging were used to investigate whether the former provides additional information regarding microstructural changes in the gray and white matter of adult patients with Moyamoya disease.MATERIALS AND METHODS:MR imaging (diffusional kurtosis imaging and DTI) was performed in 23 adult patients with Moyamoya disease and 23 age-matched controls. Three parameters were extracted from diffusional kurtosis imaging (mean kurtosis, axial kurtosis, and radial kurtosis), and 4, from DTI (fractional anisotropy, radial diffusivity, mean diffusivity, and axial diffusivity). Voxelwise analysis for these parameters was performed in the normal-appearing brain parenchyma. The association of these parameters with neuropsychological performance was also evaluated.RESULTS:Voxelwise analysis revealed the greatest differences in fractional anisotropy, followed, in order, by radial diffusivity, mean diffusivity, and mean kurtosis. In patients, diffusional kurtosis imaging parameters were decreased in the dorsal deep white matter such as the corona radiata and superior longitudinal fasciculus (P < .01), including areas without DTI abnormality. Superior longitudinal fasciculus fiber-crossing areas showed weak correlations between diffusional kurtosis imaging and DTI parameters compared with tissues with a single-fiber direction (eg, the corpus callosum). Diffusional kurtosis imaging parameters were associated with general intelligence and frontal lobe performance.CONCLUSIONS:Although DTI revealed extensive white matter changes, diffusional kurtosis imaging additionally demonstrated microstructural changes in ischemia-prone deep white matter with abundant fiber crossings. Thus, diffusional kurtosis imaging may be a useful adjunct for detecting subtle chronic ischemic injuries.

Moyamoya disease (MMD) is characterized by compensatory development of enlarged and weak basal perforating arteries (Moyamoya vessels) due to bilateral occlusive changes in the internal carotid system.¹ In addition to cerebral ischemia and intracranial hemorrhage, patients with MMD demonstrate neurocognitive issues, such as executive dysfunction, attention deficits, and working-memory disturbances.^2,3 Brain atrophy may explain cognitive impairment in the absence of infarction, but detection of these changes has been hampered by the limited sensitivity of conventional neuroimaging methods. Diffusion tensor imaging is useful for determining white matter integrity and providing parameters sensitive to changes in axons, myelin, and organelle structures.^4,5 Indeed, DTI analysis has revealed a widespread decline in white matter integrity in the normal-appearing brain with MMD.³ Thus, DTI can detect early-stage ischemic injury, which potentially predicts future cognitive outcomes. However, DTI is constrained by technical insufficiencies: It is based on the assumption that water molecules diffuse freely and that diffusion can be characterized by a Gaussian distribution.⁵In addition, the tensor model is based on the observation that in many tissues, water diffusion is anisotropic (ie, the diffusion is more liberal in some directions and more restricted in others). This anisotropic diffusion can be geometrically depicted as an ellipsoid, described by eigenvectors and eigenvalues. This model performs well in regions where fibers are aligned along a single axis. However, it fails in regions with several fiber populations aligned along intersecting axes because it cannot simultaneously map several diffusion maxima.⁶ Furthermore, because hypoxic-ischemic injury induces neurodegeneration and regression of dendrite arborization in gray matter, the diffusion properties of gray matter may also reveal the early stages of ischemic injury.^7,8 Nevertheless, analyzing isotropic or near-isotropic tissue such as gray matter by DTI may not be valid because its major parameter, fractional anisotropy (FA), reflects structure only if it is spatially oriented.⁶ A more recent method called diffusional kurtosis imaging (DKI) quantifies the deviation of water molecule diffusion from the Gaussian distribution without assuming any specific diffusion model.^6,9 Its parameters are thought to represent the complexity of tissue microstructure.⁶ Previous studies have suggested that DKI is sufficiently sensitive to detect age-related alterations in white matter microstructure.^10,11 Furthermore, measurements of diffusion anisotropy by DKI can reveal sex-related and pathologic changes in gray matter.^12,13 Thus, using DKI to evaluate the diffusion properties of gray matter and white matter in patients with MMD may be useful for detecting subtle microstructural changes due to ischemia.Diffusional kurtosis has been investigated to explore tissue reversibility in acute cerebral infarction.^14–16 However, there is a paucity of information regarding the microstructural properties measured by DKI in chronic ischemia in living humans. To expand on our prior DTI study, we investigated whether adults with MMD and no overt cerebral infarctions have altered diffusional kurtosis in the entire cerebrum. An exploratory voxel-based whole-brain analysis was performed to map regional DKI parameters and to compare DKI and DTI parameters. We also explored correlations of diffusion parameters with measures of neurocognitive impairment in an ROI analysis.     

Pulmonary cystic fibrosis in the adult: early and late radiologic findings with pathologic correlations

Radiographs of 50 patients age 17 or more with documented cystic fibrosis were reviewed. Peripheral nodular and nonvascular linear densities were common early abnormalities. Specific findings of bronchiectasis were found in 90% of all cases. Hyperinflation was seen in 76% of cases, especially in the lower lobes; atelectasis and all other abnormalities were more common in the upper (and middle) lobes. Cystic air spaces developed in 24% of cases. The severity of abnormalities (including hyperinflation, atelectasis, and bronchial changes) increased in 30 of the 39 patients with follow up for a year or more. Eight of the 15 patients who died came to autopsy. The lungs showed acute and chronic inflammation of airways, including peripheral bronchioles, with adjacent parenchymal inflammation of airways peripheral bronchioles, with adjacent parenchymal infiltrates and fibrosis. The surrounding alveoli were aerated and enhanced the visibility of the thick-walled airways, except in regions of lobar atelectasis, scarring, or active pneumonia. Large and small airway shadows can be described more precisely than by the terms "honeycombing," "interstitial" or "bronchovascular markings".     

Preliminary evidence of altered gray and white matter microstructural development in the frontal lobe of adolescents with attention-deficit hyperactivity disorder: a diffusional kurtosis imaging study

Purpose

To investigate non‐Gaussian water diffusion using diffusional kurtosis imaging (DKI) to assess age effects on gray matter (GM) and white matter (WM) microstructural changes in the prefrontal cortex (PFC) of adolescents with attention‐deficit hyperactivity disorder (ADHD) compared to typically developing controls (TDC).

Materials and Methods

In this preliminary cross‐sectional study, T1‐weighted magnetization‐prepared rapid gradient echo (MPRAGE) and DKI images were acquired at 3T from TDC (n = 13) and adolescents with ADHD (n = 12). Regression analysis of the PFC region of interest (ROI) was conducted.

Results

TDC show a significant kurtosis increase of WM microstructural complexity from 12 to 18 years of age, particularly in the radial direction, whereas WM microstructure in ADHD is stagnant in both the axial and radial directions. In ADHD, GM microstructure also lacked a significant age‐related increase in complexity as seen in TDC; only kurtosis measures were able to detect this difference.

Conclusion

These findings support the prevailing theory that ADHD is a disorder affecting frontostriatal WM. Our study is the first to directly quantify an aberrant age‐related trajectory in ADHD within GM microstructure, suggesting that the assessment of non‐Gaussian directional diffusion using DKI provides more sensitive and complementary information about tissue microstructural changes than conventional diffusion imaging methods. J. Magn. Reson. Imaging 2011;33:17–23. © 2010 Wiley‐Liss, Inc.     

扩散峰度成像的基本原理及其在脑肿瘤中的应用

扩散峰度成像（DKI）是近年发展起来的一项新的MR扩散加权成像（DWI）技术,不同于传统的DWI及扩散张量成像（DTI）,DKI主要是通过描述组织内水分子扩散运动偏离正态分布的程度,评价组织的微结构,间接反映组织生理、病理情况。DKI目前已广泛应用于中枢神经系统的临床研究,尤其在脑肿瘤方面。对DKI的基本原理及其在脑肿瘤中的临床应用予以综述。     

Characterization of Brain Microstructural Abnormalities in High Myopia Patients: A Preliminary Diffusion Kurtosis Imaging Study

ObjectiveTo evaluate microstructural damage in high myopia (HM) patients using 3T diffusion kurtosis imaging (DKI).Materials and MethodsThis prospective study included 30 HM patients and 33 age- and sex-matched healthy controls (HCs) with DKI. Kurtosis parameters including kurtosis fractional anisotropy (FA), mean kurtosis (MK), axial kurtosis (AK), and radial kurtosis (RK) as well as diffusion metrics including FA, mean diffusivity, axial diffusivity (AD), and radial diffusivity derived from DKI were obtained. Group differences in these metrics were compared using tract-based spatial statistics. Partial correlation analysis was used to evaluate correlations between microstructural changes and disease duration.ResultsCompared to HCs, HM patients showed significantly reduced AK, RK, MK, and FA and significantly increased AD, predominately in the bilateral corticospinal tract, right inferior longitudinal fasciculus, superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and left thalamus (all p < 0.05, threshold-free cluster enhancement corrected). In addition, DKI-derived kurtosis parameters (AK, RK, and MK) had negative correlations (r = −0.448 to −0.376, all p < 0.05) and diffusion parameter (AD) had positive correlations (r = 0.372 to 0.409, all p < 0.05) with disease duration.ConclusionHM patients showed microstructural alterations in the brain regions responsible for motor conduction and vision-related functions. DKI is useful for detecting white matter abnormalities in HM patients, which might be helpful for exploring and monitoring the pathogenesis of the disease.     

Effect of cerebral spinal fluid suppression for diffusional kurtosis imaging

Purpose:

To evaluate the cerebral spinal fluid (CSF) partial volume effect on diffusional kurtosis imaging (DKI) metrics in white matter and cortical gray matter.

Materials and Methods:

Four healthy volunteers participated in this study. Standard DKI and fluid‐attenuated inversion recovery (FLAIR) DKI experiments were performed using a twice‐refocused‐spin‐echo diffusion sequence. The conventional diffusion tensor imaging (DTI) metrics of fractional anisotropy (FA), mean, axial, and radial diffusivity (MD, D_‖, D_?) together with DKI metrics of mean, axial, and radial kurtosis (MK, K_‖, K_?), were measured and compared. Single image slices located above the lateral ventricles, with similar anatomical features for each subject, were selected to minimize the effect of CSF from the ventricles.

Results:

In white matter, differences of less than 10% were observed between diffusion metrics measured with standard DKI and FLAIR‐DKI sequences, suggesting minimal CSF contamination. For gray matter, conventional DTI metrics differed by 19% to 52%, reflecting significant CSF partial volume effects. Kurtosis metrics, however, changed by 11% or less, indicating greater robustness with respect to CSF contamination.

Conclusion:

Kurtosis metrics are less sensitive to CSF partial voluming in cortical gray matter than conventional diffusion metrics. The kurtosis metrics may then be more specific indicators of changes in tissue microstructure, provided the effect sizes for the changes are comparable. J. Magn. Reson. Imaging 2013;37:365–371. © 2012 Wiley Periodicals, Inc.

     

MR扩散峰度成像在腹部的研究现状

磁共振扩散峰度成像(DKI)是一种反映体内水分子非高斯分布扩散运动状态的MR成像新技术。近年来DKI已广泛应用于神经系统,并取得良好的效果。目前也逐步被应用于前列腺、肾脏、肝脏等体部脏器成像,其中在前列腺的应用最为广泛,通过应用DKI可提高对前列腺肿瘤诊断与分级的能力。就DKI技术在腹部的应用研究现状予以综述。     

White Matter Microstructural Abnormalities in Type 2 Diabetes Mellitus: A Diffusional Kurtosis Imaging Analysis

BACKGROUND AND PURPOSE:Increasing DTI studies have demonstrated that white matter microstructural abnormalities play an important role in type 2 diabetes mellitus–related cognitive impairment. In this study, the diffusional kurtosis imaging method was used to investigate WM microstructural alterations in patients with type 2 diabetes mellitus and to detect associations between diffusional kurtosis imaging metrics and clinical/cognitive measurements.MATERIALS AND METHODS:Diffusional kurtosis imaging and cognitive assessments were performed on 58 patients with type 2 diabetes mellitus and 58 controls. Voxel-based intergroup comparisons of diffusional kurtosis imaging metrics were conducted, and ROI-based intergroup comparisons were further performed. Correlations between the diffusional kurtosis imaging metrics and cognitive/clinical measurements were assessed after controlling for age, sex, and education in both patients and controls.RESULTS:Altered diffusion metrics were observed in the corpus callosum, the bilateral frontal WM, the right superior temporal WM, the left external capsule, and the pons in patients with type 2 diabetes mellitus compared with controls. The splenium of the corpus callosum and the pons had abnormal kurtosis metrics in patients with type 2 diabetes mellitus. Additionally, altered diffusion metrics in the right prefrontal WM were significantly correlated with disease duration and attention task performance in patients with type 2 diabetes mellitus.CONCLUSIONS:With both conventional diffusion and additional kurtosis metrics, diffusional kurtosis imaging can provide additional information on WM microstructural abnormalities in patients with type 2 diabetes mellitus. Our results indicate that WM microstructural abnormalities occur before cognitive decline and may be used as neuroimaging markers for predicting the early cognitive impairment in patients with type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is a common metabolic disorder with an increasing worldwide prevalence,¹ and is widely accepted as a risk factor associated with mild cognitive impairment and dementia.^2,3 A number of neuroimaging studies have demonstrated that GM structural abnormalities^4–6 might account for cognitive deficits in patients with T2DM. By contrast, studies on white matter structures, which play a vital role in transferring information between GM regions, are relatively rare. A few studies using the DTI method identified microstructural changes of WM in patients with T2DM,^7–13 and alterations of local and global network properties were also observed in patients with T2DM with the tractography method.¹⁴ In addition, the association between the WM microstructural abnormalities and cognitive performance was also revealed in patients with T2DM.^7,10,12–14However, information provided by DTI was limited, partly because diffusion metrics obtained from DTI are calculated on the basis of the assumption of Gaussian diffusion of water molecules.¹⁵ However, non-Gaussian diffusion is known to be substantial¹⁶ and is believed to result from the diffusion barriers, such as cell membranes and organelles, as well as water compartments (eg, extracellular and intracellular) with altering diffusion properties. In this study, we sought to further characterize WM changes in patients with T2DM without cognitive impairment by using diffusional kurtosis imaging (DKI), which is a clinically feasible extension of DTI that enables the examination of additional non-Gaussian diffusion effects, providing both DTI-compatible diffusion metrics and additional kurtosis metrics.¹⁷ Additionally, due to the inclusion of non-Gaussian effects, DKI-derived estimates of diffusion metrics are generally more accurate than those obtained with conventional DTI,¹⁸ and the added kurtosis metrics can yield additional information about tissue microstructure beyond that provided by diffusion metrics.The aims of this study were the following: 1) to assess the ability of DKI and DTI to identify microstructural abnormalities in patients with T2DM; 2) to investigate whether DKI-specific diffusion and kurtosis metrics could provide additional information about the WM microstructural changes; and 3) to investigate whether these microstructural abnormalities are related to clinical/cognitive variables in patients with T2DM without cognitive impairment.     

Age‐related non‐Gaussian diffusion patterns in the prefrontal brain

Purpose

To characterize age‐related MR diffusion patterns of the prefrontal brain cortex microstructure using a new method for investigating the non‐Gaussian behavior of water diffusion called diffusional kurtosis imaging (DKI).

Materials and Methods

Measures of mean diffusivity (MD), fractional anisotropy (FA) and mean kurtosis (MK) were compared in the prefrontal brain cortex of 24 healthy volunteers (adolescents, young adults, and elderly) ranging from age 13 to 85 years. A Mann‐Whitney test was used to compare subject groups with respect to the diffusion measures, and linear regression was used to characterize the change in each diffusion measure as a function of age.

Results

We found significant age‐related changes in the elderly adult group, with increase of MD and decrease of FA.

Conclusion

The current study demonstrates distinct mean kurtosis patterns for different age‐ranges, with significant age‐related correlation for mean kurtosis (MK) and MK peak position, showing that diffusional kurtosis is able to characterize and measure age‐related diffusion changes for both grey and white matter, in the developing and aging brain. J. Magn. Reson. Imaging 2008;28:1345–1350. © 2008 Wiley‐Liss, Inc.     

Diffusional kurtosis imaging of normal-appearing white matter in multiple sclerosis: preliminary clinical experience

Purpose

We evaluated diffusional changes in normal-appearing white matter (NAWM) regions remote from multiple sclerosis (MS) plaques by using diffusional kurtosis imaging (DKI) to investigate the non-Gaussian behavior of water diffusion.

Materials and methods

Participants were 11 MS patients and 6 age-matched healthy volunteers. DKI was performed on a 3-T MR imager. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), and diffusional kurtosis (DK) maps were computed. Regions of interest (ROIs) were compared in 24 cerebral regions, including the frontal, parietal, and temporal lobe white matter (WM) in controls and NAWM in MS patients.

Results

The mean FA of all ROIs was 0.468 ± 0.014 (SD) (controls) or 0.431 ± 0.029 (MS group) (P = 0.016). Mean ADC was 0.785 ± 0.034 × 10^?3 mm²/s (controls) or 0.805 ± 0.041 × 10^?3 mm²/s (MS group). The mean DK of all ROIs was 0.878 ± 0.020 (controls) or 0.823 ± 0.032 (MS group) (P = 0.002). Analysis of individual ROIs revealed significant differences in DK in 3 ROIs between normal WM and NAWM, but significant differences in ADC and FA in only one ROI each.

Conclusion

DKI may be a new sensitive indicator for detecting tissue damage in MS patients in addition to conventional diffusional evaluations, for example diffusion tensor imaging.     

磁共振扩散峰度成像在肝脏病变中的研究进展

磁共振扩散峰度成像（DKI）是扩散加权成像（DWI）、扩散张量成像（DTI）的延伸与补充,可进一步揭示生物体内水分子运动的非高斯扩散模型,更适合反映人体内微环境,较DWI、DTI技术可提供更准确、真实、丰富的组织微观结构信息。DKI技术问世以来,逐渐应用于各系统疾病的研究,尤其是在神经系统疾病中取得了显著成果,展现出良好的临床价值。DKI可反映微观信息,具有巨大的应用前景,在肝脏疾病方面的研究也越来越多,笔者就DKI在肝脏疾病中的应用予以综述。     

Structural basis for pulmonary functional imaging

An understanding of fine normal lung morphology is important for effective pulmonary functional imaging. The lung specimens must be inflated. These include (a) unfixed, inflated lung specimen, (b) formaldehyde fixed lung specimen, (c) fixed, inflated dry lung specimen, and (d) histology specimen. Photography, magnified view, radiograph, computed tomography, and histology of these specimens are demonstrated. From a standpoint of diagnostic imaging, the main normal lung structures consist of airways (bronchi and bronchioles), alveoli, pulmonary vessels, secondary pulmonary lobules, and subpleural pulmonary lymphatic channels. This review summarizes fine radiologic normal lung morphology as an aid to effective pulmonary functional imaging.     

A simple isotropic phantom for diffusional kurtosis imaging

Dairy cream is shown to be a simple, inexpensive, isotropic phantom useful for testing diffusional kurtosis imaging data acquisition and postprocessing. The MR-visible protons of cream exhibit slow and fast diffusion components, attributed to the fat and water protons, respectively, which give rise to a diffusion coefficient of 1.1 μm(2)/ms and a diffusional kurtosis of 1.2. These parameter values are similar to those observed in vivo for human brain. Heating the cream is found to increase the T(2)-relaxation time of the fat protons, which facilitates the evaluation of typical diffusional kurtosis imaging protocols used in clinical settings. The diffusion coefficient and diffusional kurtosis can both be measured directly and predicted based on the corresponding diffusion parameters of the individual water and fat components, which are independently measurable due to chemical shift misregistration, thus providing an important consistency check. This phantom is proposed as a convenient calibration standard for multicenter diffusional kurtosis imaging studies.     

A preliminary diffusional kurtosis imaging study of Parkinson disease: comparison with conventional diffusion tensor imaging

Introduction

Diffusional kurtosis imaging (DKI) is a more sensitive technique than conventional diffusion tensor imaging (DTI) for assessing tissue microstructure. In particular, it quantifies the microstructural integrity of white matter, even in the presence of crossing fibers. The aim of this preliminary study was to compare how DKI and DTI show white matter alterations in Parkinson disease (PD).

Methods

DKI scans were obtained with a 3-T magnetic resonance imager from 12 patients with PD and 10 healthy controls matched by age and sex. Tract-based spatial statistics were used to compare the mean kurtosis (MK), mean diffusivity (MD), and fractional anisotropy (FA) maps of the PD patient group and the control group. In addition, a region-of-interest analysis was performed for the area of the posterior corona radiata and superior longitudinal fasciculus (SLF) fiber crossing.

Results

FA values in the frontal white matter were significantly lower in PD patients than in healthy controls. Reductions in MK occurred more extensively throughout the brain: in addition to frontal white matter, MK was lower in the parietal, occipital, and right temporal white matter. The MK value of the area of the posterior corona radiata and SLF fiber crossing was also lower in the PD group.

Conclusion

DKI detects changes in the cerebral white matter of PD patients more sensitively than conventional DTI. In addition, DKI is useful for evaluating crossing fibers. By providing a sensitive index of brain pathology in PD, DKI may enable improved monitoring of disease progression.     

Updates in advanced diffusion-weighted magnetic resonance imaging techniques in the evaluation of prostate cancer

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer. It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DW-MRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the non-mono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging (DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.