Quality Comparison of 3 Tesla multiparametric MRI of the prostate using a flexible surface receiver coil versus conventional surface coil plus endorectal coil setup

Abstract

Purpose To subjectively and quantitatively compare the quality of 3 Tesla magnetic resonance imaging of the prostate acquired with a novel flexible surface coil (FSC) and with a conventional endorectal coil (ERC). Methods Six radiologists independently reviewed 200 pairs of axial, high-resolution T2-weighted and diffusion-weighted image data sets, each containing one examination acquired with the FSC and one with the ERC, respectively. Readers selected their preferred examination from each pair and assessed every single examination using six quality criteria on 4-point scales. Signal-to-noise ratios were measured and compared. Results Two readers preferred FSC acquisition (36.5-45%) over ERC acquisition (13.5-15%) for both sequences combined, and four readers preferred ERC acquisition (41-46%). Analysis of pooled responses for both sequences from all readers shows no significant preference for FSC or ERC. Analysis of the individual sequences revealed a pooled preference for the FSC in T2WI (38.7% vs 17.8%) and for the ERC in DWI (50.9% vs 19.6%). Patients' weight was the only weak predictor of a preference for the ERC acquisition (p = 0.04). SNR and CNR were significantly higher in the ERC acquisitions (p<0.001) except CNR differentiating tumor lesions from benign prostate (p=0.1). Conclusion Although readers have strong individual preferences, comparable subjective image quality can be obtained for prostate MRI with an ERC and the novel FSC. ERC imaging might be particularly valuable for sequences with inherently lower SNR as DWI and larger patients whereas the FSC is generally preferred in T2WI. FSC imaging generates a lower SNR than with an ERC.

Human prostate MRI at ultrahigh‐performance gradient: A feasibility study

“…The coils could not provide a comparable SNR efficiency compared with the two 48-channel coils used in the clinical whole-body MRI systems. Lightweight flexible RF receive coils with more channels 27,28 may be used to further improve the SNR for prostate MRI. We also note that the SNR calculation was based on the magnitude signal, and the ADC was calculated by a linear fitting.…”

Picture Perfect: The Status of Image Quality in Prostate MRI

“…At the same magnetic field strength, it is of no surprise that there are numerous studies that validate the proposed superiority in SNR that results from using an ERC 30–32 . Few studies have evaluated CNR, although Ullrich et al 31 did not observe improved discrimination between benign and cancerous prostate.…”

“…29 At the same magnetic field strength, it is of no surprise that there are numerous studies that validate the proposed superiority in SNR that results from using an ERC. [30][31][32] Few studies have evaluated CNR, although Ullrich et al 31 did not observe improved discrimination between benign and cancerous prostate. The expected improvement in image quality, as rated by radiologists on a 1 to 5 Likert scale, has been shown for DWI 32,33 and T2-WI 34 but certain studies have also reported no superiority with either set up.…”

“…30,35 Where a 1 to 4 Likert scale was used to assess image quality, no significant difference was found. 31 In terms of localization and staging, one group found that using an ERC improved image quality for visualizing the different zones of the prostate and possible lesions, 36 although they reported no significant difference when combining assessment of the capsule and possible invasion, neurovascular bundle and rectoprostatic angle into an average score. Other groups have demonstrated increased artifacts when using an ERC on T2-WI 30,31,34 and DWI, 33 while Ullrich et al 31 found fewer motion-related artifacts on DWI.…”

“…The expected improvement in image quality, as rated by radiologists on a 1 to 5 Likert scale, has been shown for DWI 32,33 and T2‐WI 34 but certain studies have also reported no superiority with either set up 30,35 . Where a 1 to 4 Likert scale was used to assess image quality, no significant difference was found 31 . In terms of localization and staging, one group found that using an ERC improved image quality for visualizing the different zones of the prostate and possible lesions, 36 although they reported no significant difference when combining assessment of the capsule and possible invasion, neurovascular bundle and rectoprostatic angle into an average score.…”