In MR elastography (MRE) stiffness maps are generated by local frequency estimation[1], direct Helmholtz inversion[2], finite element methods[3] or multifrequency direct inversion[4]. Latter method, multifrequency dual elastic visco (MDEV) inversion, has been used for calculating high resolution elastograms with pixel-wise resolved anatomical details of elasticity and viscosity[5]. Despite large improvements in the resolution capacity of MRE by MDEV inversion, multifrequency based elastograms still suffers from noise[6].To develop and test noise-robust wave-number MDEV (k-MDEV) inversion for high resolution MRE in abdominal organs.k-MDEV retrieves wave numbers (k) of multifrequency shear wave fields by first-order derivative operators. Other than in conventional phase-gradient based MRE[7], the gradient operator is applied to plane waves rather than to the phase of the complex field. To account for attenuation effects, the fields are normalized by the magnitude of the waves prior to the gradient calculation. Plane waves are obtained by conventional spatio-directional filters. The entire processing pipline is currently in 2D.Fig.1 compares wave speed- (c)-maps produced by classical single-frequency direct inversion, MDEV-inversion and the proposed k-MDEV inversion in a transversal slice through the abdomen of a healthy volunteer. Especially in deeper areas where shear waves are more damped, the new method produces consistent c-values enabling us to analyze multiple types of tissue from the same scan. We identified the liver -left lobe(1), right lobe(2), caudal lobe(3)-, the spleen(4), the kidney(5), the intervertebral disk(6), spinal cord(7), stomach, muscle, and subcutaneous fat (numbers refer to Fig.1). Fig.2 presents a c-map of the uterine body and cervix in a healthy volunteer. Recently MDEV-inversion based MMRE[8] found uterine tissue to be stiffer than cervical tissue. Here, this is confirmed in the wave speed values in both types of tissues. k-MDEV’s spatial resolution enabled the detection of c variations in both tissues through the menstrual cycle which are mainly attributable to periodic thickening of the functional layer[8]. Group mean values by organ are listed in the table given in Fig.3. which includes comparisons with c-values derived from reports in the literature. Most multifrequency MRE values in the literature are given as magnitude |G*| and phase angle φ of the complex shear modulus G*. For conversion to wave speed values, the relation c² = 2|G*|/ρ/(cos φ +1) was used[9] with ρ as the tissue's density.Values agree well across methods, as indicated by the overlap of standard deviations. Fig.4 shows c-maps for a healthy volunteer and patients with mild (F2) and severe fibrosis (F4). Wave speed values of liver and spleen increase with fibrosis. Furthermore, heterogeneity of c increases from healthy liver (≈11% variation), mild fibrosis (≈15% variation) to severe fibrosis (variation of values ≈20%).k-MDEV processing builds on multifrequency wave field acquisition[5], multifrequency inversion[4], gradient-based spatial phase unwrapping[10], and directional filtering[7]. The novelty of k-MDEV inversion is found in noise treatment, both by smoothing complex-valued raw MRI data prior to phase unwrapping and by computation of the phase gradient which does not suffer from phase discontinuities as encountered in previous phase-gradient based MRE[1]. In its current implementation, k-MDEV is entirely 2D, which does not require high resolution in the z-direction. For 3D k-MDEV inversion, directional filtering in the z-direction would be required, and this would be impoverished by the small number of slices that can be acquired with current MRE protocols tailored for abdominal imaging. We anticipate extension of k-MDEV inversion to 3D to be possible in view of the latest developments in full brain MRE[11], which would deliver richer frequency information along the z axis. In summary k-MDEV inversion provides a noise-robust method for high-resolution MRE for multiple applications in abdominal imaging.