A comparative evaluation of a RARE-based single-shot pulse sequence for diffusion-weighted MRI of musculoskeletal soft-tissue tumors

Abstract

The purpose of this study was to evaluate the feasibility of a centric-reordered modified rapid acquisition with relaxation enhancement (mRARE) sequence for single-shot diffusion-weighted magnetic resonance imaging (DWI) of soft-tissue tumors in the musculoskeletal system. In the evaluation of this sequence, DWI was performed in a liquid phantom, in excised human tumor samples embedded in bovine muscle, and in nine patients suffering from different types of soft-tissue tumors. The measurements were compared to DWI using a spin-echo sequence and a single-shot echo planar imaging (EPI) sequence. The phantom measurements in water and dimethyl sulfoxide showed a difference of less than 5% when comparing the apparent diffusion coefficients (ADCs) determined by the mRARE sequence and the two other techniques. Comparing mRARE and EPI, the differences in the ADCs were about 10% in the excised tumor tissue and, typically, about 15% in vivo. ADCs between 0.8 x 10(-3) mm2/s and 1.4 x 10(-3) mm2/s, depending on the tumor type, were found in solid tumor tissue; in cystic tumor areas, ADCs greater than 2.0 x 10(-3) mm2/s were determined with the mRARE and the EPI sequences. Diffusion-weighted images of the mRARE sequence were less distorted than those acquired with the single-shot EPI sequence, and provided more anatomic information, since the muscle and fat signals were considerably higher.

Image quality assessment of single-shot turbo spin echo diffusion-weighted imaging with parallel imaging technique: a phantom study

“…Previous reports also described the influence of imaging sequences on ADC values. 23,24 Notably, the reproducibility of ADC values obtained with TSE-DWI was superior to that reported in a previous study, irrespective of AF. 9 TSE-DWI produced fewer artefacts compared with EPI-DWI and therefore provided more accurate ADC measurements.…”

Posttraumatic pseudolipoma: MRI appearances

“…There are no specific findings, such as hemosiderin deposits or scar tissue, that confirm a posttraumatic lesion. It should be noted, however, that for one of our patient, MRI demonstrated the presence of fibrous sep- [18][19][20] The actual recommended treatment for pseudolipomas is liposuction. The benefits of liposuction are smaller and hardly visible scars and a better clinical outcome.…”

Technical Note: Diffusion‐weighted MRI with minimal distortion in head‐and‐neck radiotherapy using a turbo spin echo acquisition method

“…During the initial echoes of the echo train of DW-SPLICE, there is still an intensity variation between consecutive echoes. 19,21,24 The addition of more dummy acquisitions at the start of the echo train reduces the intensity variations when the center of k-space is acquired. This will increase TE however, which leads to a reduced SNR.…”

“…The signal intensities from the E 1 and E 2 echo families vary during the initial echoes. 19,21,24 Therefore, an extra acquisition of DW-SPLICE was done using additional (5 total) leading dummy echoes.…”