Feasibility Study of 3-T DWI of the Prostate: Readout-Segmented Versus Single-Shot Echo-Planar Imaging

Abstract

G e nit ou r i n a r y I m ag i ng • O r ig i n a l Re s e a rc h AJR 2015; 205:70-76 0361-803X/15/2051-70 OBJECTIVE. The purpose of this prospective study was to assess the clinical utility of generalized autocalibrating partial parallel acquisition (GRAPPA)-accelerated readoutsegmented echo-planar imaging (rs-EPI) DWI and compare it with standard single-shot EPI ( ss-EPI) DWI in visualization of the prostate during 3-T MRI.SUBJECTS AND METHODS. One hundred sixteen consecutively registered patients (mean age, 63.5 years; range 24-93 years) underwent 3-T MRI that included rs-EPI DWI and standard ss-EPI DWI with identical FOVs, slices, acceleration factors, b values, and image postprocessing procedure. The datasets were independently evaluated by two blinded radiologists. Images were evaluated for sharpness, anatomic distortion, imaging contrast, lesion conspicuity, detailed anatomic visualization, and overall image quality on a 5-point Likert scale (1, nondiagnostic; 5, excellent).RESULTS. The kappa values were 0.73 for image sharpness, 0.71 for anatomic distortion, 0.54 for imaging contrast, 0.56 for lesion conspicuity, 0.61 for detailed anatomic visualization, and 0.63 for overall image quality (all p < 0.05), indicating moderate to substantial agreement between the two observers. The mean Likert scores for standard ss-EPI and rs-EPI were as follows: image sharpness, 2.9 and 4.6; distortion level, 2.8 and 4.4; contrast, 3.1 and 3.8; lesion conspicuity, 3.0 and 4.0; structure, 3.1 and 4.2; and overall image quality, 3.1 and 4.2. The rs-EPI DWI sequence was associated with significantly better image quality and fewer susceptibility artifacts than was ss-EPI (all p < 0.05). The rs-EPI sequence was considered better overall in 90% of cases.CONCLUSION. The technique of rs-EPI DWI combined with GRAPPA enables robust prostate imaging with high image quality and may provide great benefit in routine clinical practice. Li et al. DWI of Prostate Genitourinary Imaging Original Research Downloaded from www.ajronline.org by NYU Langone Med Ctr-Sch of Med on 07/02/15 from IP address 128.122.253.228. Copyright ARRS. For personal use only; all rights reserved AJR:205, July 2015

Feasibility of accelerated simultaneous multislice diffusion‐weighted MRI of the prostate

“…For reasons of comparability, we adjusted the acquisition parameters of DW‐EPI SMS to the DW‐EPI SS standard and did not assess the potential for acquiring higher spatial resolution, because current DWI sequences with special focus for improving image resolution rely on multishot readout segmented EPI techniques. Several studies have demonstrated the feasibility of this approach for a significant reduction of distortion and susceptibility artifacts; however, at the cost of lengthening the total scan time . To benefit from both accelerated acquisition speed and high spatial resolution, a combination of the SMS‐technique and readout segmented DW‐EPI sequences appears worthwhile to further improve DWI.…”

“…Due to an expected increase in patient numbers, optimizing patient comfort and throughput is desirable. Most commonly, conventional echo planar imaging based single‐shot (DW‐EPI SS ) DWI sequences are implemented in multiparametric MRI protocols, which provide reliable image quality, but show a high rate of susceptibility artifacts . At the same time, spatial resolution is limited, with the potential risk of missing subtle findings .…”

Differentiation of prostate cancer lesions in the Transition Zone by diffusion-weighted MRI

“…More advanced functional MR imaging sequences in a custom multiparametric MR imaging (mpMRI) exam have been shown to significantly improve the performance of MRI in cancer diagnosis [9]. In addition, DWI has become a useful tool for differentiating malignant and benign prostatic tissue due to high contrast resolution and the quantitative apparent diffusion coefficient (ADC) [6], [10]. DWI reflects and measures the diffusion of water molecules within biological tissues due to thermal Brownian motion.…”

Segmented diffusion-weighted imaging of the prostate: Application to transperineal in-bore 3T MR image-guided targeted biopsy

“…However, we are not aware of a study focusing specifically on the imaging of the prostate and quantification of the distortion effects. One exception is a recent study by Li et al [24] that compared SS- DWI and MS-DWI of the prostate using qualitative assessment of a variety of factors such as distortion and lesion conspicuity, targeting primarily staging workflows of the routine clinical care. In this study we include quantitative assessment of both distortion and targeting error, which are critical for image-guided therapy applications.…”