br As all pulse sequences were
As all pulse sequences were read independently, a false positive in one sequence would not add to overall false posi-tivity by other sequences. The aim of this study was to elucidate detection and sensitivity of each sequence inde-pendently and without reader bias. However, the best way to truly assess combination detection and effect of each sequence on overall false positive rate would be to test all
biparametric and triparametric combinations of imaging sequences in a prospective reading study, in addition to test-ing single sequence detection as is done here. Despite this, we have shown that false positive findings are lower in com-binations of independent positivity, as demonstrated by higher CDR.
Our study has some limitations. First, our study cohort had only case patients who underwent subsequent radical prosta-tectomy and therefore harbored possibly higher grade can-cers, leading to a selection bias compared to an average population of all patients undergoing mpMRI. Our defini-tion for cancer was Gleason score 3 + 3, and the randomly selected lesion population consisted of only Gleason 3 + 4 disease and above. We included control patients so as to reduce this effect. However, control populations are some-what inherently limited by being only biopsy-proven since
Academic Radiology, Vol 26, No 1, January 2019 PROSTATE MPMRI INDIVIDUAL SEQUENCE CANCER DETECTION
surgery cannot be offered to these patients. Additionally, as this was an exploratory evaluation with no set predicted detection rate for each sequence, the population used in this study was relatively small at 45 patients. Our results should be validated in a similar, optimally larger cohort. Moreover, this experimental read out study included three expert readers, but it may be more ideal to include readers with a greater Bortezomib (PS-341) of experience. The readers' detection guidelines fol-lowed a framework outlined in PI-RADSv2 to optimize standardization across readers, but at the cost of standardiza-tion, perhaps detection instructions could be broadened to include in-house interpretation practices and central zone lesion identification.
In conclusion, when multiple observers independently read individual pulse sequences on prostate MRI, DWI achieves the highest cancer detection in both prostate zones; however, T2W and DCE MRI also add independent value to prostate cancer detection. These findings can serve as groundwork for future refinement of diagnostic criteria for mpMRI of the prostate.
This project has been funded in whole or in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. HHSN261200800001E. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.
The National Institutes of Health (NIH) Medical Research Scholars Program is a public-private partnership supported jointly by the NIH and generous contributions to the Foundation for the NIH from the Doris Duke Charita-ble Foundation, The American Association for Dental Research, the Colgate-Palmolive Company, Genentech and alumni of student research programs and other individ-ual supporters via contributions to the Foundation for the National Institutes of Health.
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