Quantitative susceptibility mapping of prostate with separate calculations for water and fat regions for reducing shading artifacts

Quantitative susceptibility mapping of the head‐and‐neck using SMURF fat‐water imaging with chemical shift and relaxation rate corrections

“…Additionally, to reduce shading artifacts, separate susceptibility maps for fat and water could be calculated separately from SMURF images and then combined. 17 This would, however, make the approach more sensitive to masking and would benefit from, and likely be dependent upon, a TFI approach. Recently, a new preconditioned water-fat TFI (wfTFI) algorithm 68 was developed and used to reduce background field-removal artifacts, noise amplification, and streaking artifacts in QSM of water-fat regions.…”

“…Although in‐phase imaging 12,23,24,26 and Dixon imaging 9,13,25,44 are often used in these cases to remove Type 2 (phase discrepancy) CSA, we have shown that the correction of Type 1 (displacement) CSA and also of the bias due to fat‐water relaxation differences, which cannot be performed with those approaches, is required for accurate susceptibility mapping. Additionally, to reduce shading artifacts, separate susceptibility maps for fat and water could be calculated separately from SMURF images and then combined 17 . This would, however, make the approach more sensitive to masking and would benefit from, and likely be dependent upon, a TFI approach.…”

“…2 QSM provides excellent contrast in the imaging of calcifications, hemorrhages, and iron depositions, as well as tissue microstructure and oxygenation. 3 The technique has found application including the assessment of Alzheimer and Parkinson disease, Multiple Sclerosis (MS), the grading of tumors and monitoring of their growth, [4][5][6] and the past decade has seen an increase of interest in QSM outside the brain: in the liver, [7][8][9][10][11] breast, 3,12,13 kidney, 14 prostate, [15][16][17] heart, [18][19][20] knee, 21 trabecular bone, 22 spine, 23 and the entire head-and-neck region. [24][25][26][27][28][29] Compared to brainonly QSMs, susceptibility mapping of the head-and-neck allows the visualization of deep gray matter nuclei in the brainstem 30 -potential targets for deep brain stimulation 31,32 -MS lesions 33 in the brainstem, and visualization and assessment of tumors in the facial skull; epi-, naso-, and oropharynx; the base of the tongue and mouth; salivary glands; and possible regional lymph nodes.…”

Quantitative Susceptibility Mapping versus R2*-based Histogram Analysis for Evaluating Liver Fibrosis: Preliminary Results

“…QSM and R2* reconstructions were performed using the WF separation method with the multipeak fat correction, as previously described. 25,26 Briefly, the susceptibilities for the water and fat regions were calculated separately. Then, the two reconstructed images were combined to create the final QSM image, reducing shading artifacts at the edges of fat tissue.…”

“…In this regard, the water-fat (WF) separation method allows accurate QSM reconstruction. 25 It also improves the homogeneity and reproducibility of susceptibility values in the upper abdominal organs of normal subjects. 26 To the best of our knowledge, few studies have compared QSM analysis and the status of liver fibrosis.…”