Multiparametric Quantitative MRI for the Detection of IgA Nephropathy Using Tomoelastography, DWI, and BOLD Imaging

Abstract

Objectives: The aim of this study was to noninvasively evaluate changes in renal stiffness, diffusion, and oxygenation in patients with chronic, advanced stage immunoglobulin A nephropathy (IgAN) by multiparametric magnetic resonance imaging using tomoelastography, diffusion-weighted imaging (DWI), and blood oxygen level-dependent (BOLD) imaging. Materials and Methods: In this prospective study, 32 subjects (16 patients with biopsy-proven IgAN and 16 age-and sex-matched healthy controls) underwent multifrequency magnetic resonance elastography with tomoelastography postprocessing at 4 frequencies from 40 to 70 Hz to generate shear wave speed (meter per second) maps reflecting tissue stiffness. In addition, DWI and BOLD imaging were performed to determine the apparent diffusion coefficient in square millimeter per second and T2* relaxation time in milliseconds, respectively. Regions including the entire renal parenchyma of both kidneys were analyzed. Areas under the receiver operating characteristic (AUCs) curve were calculated to test diagnostic performance. Clinical parameters such as estimated glomerular filtration rate and protein-tocreatinine ratio were determined and correlated with imaging findings. Results: Success rates of tomoelastography, DWI, and BOLD imaging regarding both kidneys were 100%, 91%, and 87%, respectively. Shear wave speed was decreased in IgAN (−21%, P < 0.0001), accompanied by lower apparent diffusion coefficient values (−12%, P = 0.004). BOLD imaging was not sensitive to IgAN (P = 0.12). Tomoelastography detected IgAN with higher diagnostic accuracy than DWI (area under the curve = 0.9 vs 0.8) and positively correlated with estimated glomerular filtration rate (r = 0.66, P = 0.006). Conclusions: Chronic, advanced stage IgAN is associated with renal softening and restricted water diffusion. Tomoelastography is superior to DWI and BOLD imaging in detecting IgAN.

Fusing acceleration and saturation techniques with wave amplitude labeling of time‐shifted zeniths MR elastography

“…The difference between SC S2 and FW CS3 demonstrated a bias of −0.005 kPa and the 95% limits of agreements of −0. 15 2 with the FASTWALTZ (C-SENSE = 3) sequence (red). The factors in the figure are the net acceleration factor.…”

“…The multifrequency approach may allow measurement of parameters that are independent of frequency through viscoelastic modeling or via analysis of the regression line of stiffness and frequency, and achieves elastograms with superior spatial resolution. [10][11][12][13][14][15][16] Furthermore, motion-encoding gradients (MEG) can be applied in 3 orthogonal directions to obtain more accurate elasticity maps or determine elasticity tensors. However, despite the increased information provided by these techniques, neither multidirectional nor multifrequency techniques are in routine clinical practice for liver MRE.…”

Reduction of breathing artifacts in multifrequency magnetic resonance elastography of the abdomen

“…Abdominal magnetic resonance elastography (MRE) is gaining in importance for the clinical diagnosis of a large variety of diseases that alter the mechanical properties of tissues such as liver fibrosis, [1][2][3][4][5] portal hypertension, 6,7 renal dysfunction, [8][9][10] and tumors. [11][12][13][14] Since the introduction of MRE in 1995 by Muthupillai et al, 15 various MRE methods tailored for clinical examinations of the abdomen have been proposed.…”

“…Published studies report multifrequency 3D MRE of abdominal organs with up to eight wave dynamics consecutively acquired at up to seven frequencies, resulting in total acquisition times exceeding 5 minutes, during which patients are allowed to breathe freely. [8][9][10]24,25 The same protocol with breath-hold acquisition would exceed 20 minutes. 26 Nevertheless, there are good reasons for multifrequency MRE of abdominal organs, including measurement of viscoelastic dispersion or improved detail resolution.…”

“…Published studies report multifrequency 3D MRE of abdominal organs with up to eight wave dynamics consecutively acquired at up to seven frequencies, resulting in total acquisition times exceeding 5 minutes, during which patients are allowed to breathe freely 8‐10,24,25 . The same protocol with breath‐hold acquisition would exceed 20 minutes 26 .…”