In Pi-Rads v2 there are technical recommendations for performance of multiparametric MRI (mpMRI) of the prostate. When using this protocol there are several issues that lead to suboptimal or non-diagnostic images that remain unaddressed. Some of these can be mitigated through altering patient preparation or a changing of pulse sequence parameters. Further optimization and development of robust pulse sequences and imaging systems to improve prostate MRI image quality is an unmet need that can benefit from further research. A second critical area in need of further development is related to value which goes hand in hand with cost reduction. This is also tied to the growing and controversial concerns related to repeated Gd administration for DCE MRI and the unknown long-term effects of Gd deposition in the brain in an otherwise healthy patient population with long life expectancy. The necessity of DCE MRI and the potential of proton spectroscopy to replace DCE MRI are other potential areas of innovation.
A pdf including parts of the final presentation will be available at http://www.mybodymri.com at the time of presentation.
In Pi-Rads v2 there are technical recommendations for performance of multiparametric MRI (mpMRI) of the prostate. When using this protocol there are several issues that lead to suboptimal or non-diagnostic images that remain unaddressed. Some of these can be mitigated through altering patient preparation or a changing of pulse sequence parameters. Further optimization and development of robust pulse sequences and imaging systems to improve prostate MRI image quality is an unmet need that can benefit from further research.
A second critical area in need of further development is related to value which goes hand in hand with cost reduction. This is also tied to the growing and controversial concerns related to repeated Gd administration for DCE MRI and the unknown long-term effects of Gd deposition in the brain in an otherwise healthy patient population with long life expectancy. The necessity of DCE MRI and the potential of proton spectroscopy to replace DCE MRI are other potential areas of innovation.
Image Quality
Susceptibility Effects – Bowel gas and Hip Prosthesis
Rectal distention with gas or stool negatively affects image quality on T2 and DWI sequences due to increase rectal motion as well as susceptibility from bowel gas (1). The use of fast recovery T2 weighted sequences can help reduce scan time compared to standard FSE T2 acquisitions. Although evacuation of the bowel prior to mpMRI has the potential to improve image quality evidence on what is the best “recipe” to achieve this is not clear with conflicting reports in the literature (2–5) Options include the use of an anti-peristaltic Hyoscine butylbromide (Buscopan®), self administered fleet enema, instructing the patient to evacuate their bowels prior to MRI, full cleansing bowel prep, keeping patients NPO for 4-6 hours prior to the MRI, use of an endorectal coil with good balloon distention with fluid (off label)(6) to keep gas out of rectum. We no longer use anti-peristaltic agents due to the overhead of nursing and monitoring required after normal working hours.
DWI – Pulse sequence options
Pi-Rads v2 recommends either calculated or acquired DWI images with a b-value >=1400. DWI signal can be maximized and calculated b1400-2000 images can be generated by limiting the maximum b-value to 0 and 800-1000. We do this and acquire a separate 0-1600 b value pair using a readout segmented DWI sequence if there is bowel gas. Further reduction in susceptibility can be achieved through the use of partial parallel imaging with reduction factors of 2 routinely applied to reduce the readout. This can be helpful in patients with hip prosthesis Selective excitation of a subvolume of tissue is now available as are readout segmented EPI sequences which both reduce the readout length (7). There have been anecdotal reports of inadequate SNR or alterations in local tissue contrast with some of the manufacturer implementation of these approaches however artifact has been shown to be reduced with bowel gas and hip prosthesis (8)
Is DCE MRI necessary?
The jury is still out. The early literature is conflicting but more studies are showing little added value of contrast injection(9,10). DCE MRI likely has some role in increasing conspicuity of subtle lesion on DWI or helping make up for technical failure in DWI acquisition. It is unclear whether Gd contrast agents must be administered on every follow-up examination. Further study of the incremental value of Gd and DCE MRI in mpMRI is needed
New Strategies
A single hybrid acquisition that combines T2 and Diffusion weighting while minimizing susceptibility(11) or an MRI fingerprinting approach(12) combined with AI, ML analysis are active areas of investigation in the MRI community. A quick robust single MRI sequence not requiring contrast agent remains a goal for the MRI community in prostate MRI.
1. Caglic I, Hansen NL, Slough RA, Patterson AJ, Barrett T. Evaluating the effect of rectal distension on prostate multiparametric MRI image quality. Eur J Radiol. 2017;90:174–180.
2. Roethke MC, Kuru TH, Radbruch A, Hadaschik B, Schlemmer H-PP. Prostate magnetic resonance imaging at 3 Tesla: Is administration of hyoscine-N-butyl-bromide mandatory? World J Radiol. 2013;5(7):259–263http://www.ncbi.nlm.nih.gov/pubmed/23908696%5Cnhttp://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=PMC3730080.
3. Lim C, Quon J, McInnes M, Shabana WM, El-Khodary M, Schieda N. Does a cleansing enema improve image quality of 3T surface coil multiparametric prostate MRI? J Magn Reson Imaging. 2015;42(3):689–697.
4. Haggman M, Norberg M, de la Torre M, Fritjofsson A, Busch C. Characterization of localized prostatic cancer: distribution, grading and pT-staging in radical prostatectomy specimens. Scand J Urol Nephrol. 1993;27(1):7–13.
5. Johnson W, Taylor MB, Carrington BM, Bonington SC, Swindell R. The value of hyoscine butylbromide in pelvic MRI. Clin Radiol. 2007;62(11):1087–1093.
6. Rosen Y, Bloch BN, Lenkinski RE, Greenman RL, Marquis RP, Rofsky NM. 3T MR of the prostate: reducing susceptibility gradients by inflating the endorectal coil with a barium sulfate suspension. Magn Reson Med. 2007/04/26. 2007;57(5):898–904http://www.ncbi.nlm.nih.gov/pubmed/17457870.
7. Li L, Wang L, Deng M, et al. Feasibility study of 3-T DWI of the prostate: Readout-segmented versus single-shot echo-planar imaging. Am J Roentgenol. 2015;205(1):70–76.
8. Rosenkrantz AB, Taneja SS. Use of Reduced Field-of-View Acquisition to Improve Prostate Cancer Visualization on Diffusion-Weighted Magnetic Resonance Imaging in the Presence of Hip Implants: Report of 2 Cases. Curr Probl Diagn Radiol. 2018;47(2):125–127.
9. Di Campli E, Delli Pizzi A, Seccia B, et al. Diagnostic accuracy of biparametric vs multiparametric MRI in clinically significant prostate cancer: Comparison between readers with different experience. Eur J Radiol. 2018;101:17–23.
10. Kuhl CK, Bruhn R, Krämer N, Nebelung S, Heidenreich A, Schrading S. Abbreviated Biparametric Prostate MR Imaging in Men with Elevated Prostate-specific Antigen. Radiology. 2017;285(2):493–505http://pubs.rsna.org/doi/10.1148/radiol.2017170129.
11. Sadinski M, Karczmar G, Peng Y, et al. Pilot study of the use of hybrid multidimensional t2-weighted imaging-dwi for the diagnosis of prostate cancer and evaluation of gleason score. Am J Roentgenol. 2016;207(3):592–598http://www.embase.com/search/results?subaction=viewrecord&from=export&id=L611828403%0Ahttp://dx.doi.org/10.2214/AJR.15.15626.
12. Yu AC, Badve C, Ponsky LE, et al. Development of a Combined MR Fingerprinting and Diffusion Examination for Prostate Cancer. Radiology. 2017;283(3):729–738http://pubs.rsna.org/doi/10.1148/radiol.2017161599.