Synopsis
. We proposed an abbreviated, short MRI-protocol that is limited to the
early post-contrast period, then to use standard image reconstruction tools
(maximum intensity projection, MIP) to allow a very fast overview of the
imaging volume, and finally to have expert radiologists interpret this limited
protocol. Aim was to substantially
reduce image acquisition and reading time of screening-MRI. Long term goal is
to increase the access to screening breast-MRI.Breast-MRI screening is
associated with high direct and indirect costs. This, together with the lack of
sites that offer high level breast-MRI, limits the clinical access to screening
MRI. One reason for the high cost is the fact that current breast-MRI protocols
are time consuming to acquire and to read. A typical MRI study occupies the MR
system for up to 40 minutes and generates several hundred images. Although MRI
pulse-sequence protocols of the different MRI-screening trials conducted so far
vary widely, they all have in common that for screening, the same MRI
acquisition-protocol had been used that was also used for diagnostic purposes
in the respective institutions.
Mammographic screening, on the
other hand, is a highly standardized and relatively simple procedure. Women
undergo mammography, usually without clinical examination, and the resulting
mammograms are interpreted by highly trained and specialized screening
radiologists who batch read up to 100 mammograms per hour.
To solve this dilemma, we
proposed to use an approach to breast-MRI screening that pursues a concept
similar to that of mammographic screening programs. We proposed an abbreviated,
short MRI-protocol that is limited to the early post-contrast period, then to
use standard image reconstruction tools (maximum intensity projection, MIP) to
allow a very fast overview of the imaging volume, and finally to have expert
radiologists interpret this limited protocol.
Aim was to substantially reduce image acquisition and reading time of
screening-MRI. Long term goal is to increase the access to screening
breast-MRI.
We hypothesized that an
abbreviated protocol, i.e. withholding diagnostic information, should be
associated with a reduced diagnostic accuracy, but suspected that it may be
acceptable to give up some of the very high sensitivity of regular screening
breast-MRI, and trade it for acquisition and interpretation speed.
In a prospective reader study,
followed by a two-year validation phase,
we recruited 443 women who underwent a total 606 screening rounds with the
abbreviated and the full breast MRI screening protocol. The abbreviated
protocol consisted of only one pre- and one post contrast acqusition, plus the
respective First Post Contrast Subtracted, or FAST, images, and their MIP
reconstruction. Women at moderately to mildly increased risk were offered MRI
for screening only if they had undergone two view digital mammography, double
read by two experienced breast radiologist with negative or benign results, as
well as a high resolution ultrasound screening study of the breast, conducted
by dedicated breast radiologist, again with negative or benign results. We
found that the diagnostic utility of the abbreviated breast-MRI screening
protocol was comparable or even identical to that of the routine breast-MRI
screening protocol. The abbreviated protocol, however, allowed a substantial
reduction of image acquisition time (i.e. MR system time of 3 minutes) as well
as image interpretation time (i.e. expert radiologist reading-time of 3 seconds
for MIP, and under 30 seconds for the FAST images). Reading the MIP-image
helped exclude presence of breast-cancer with a negative predictive value of
close to 100 %. Reading FAST images helped correctly characterise positive MIP
findings. With the abbreviated protocol,
the same added cancer yield was achieved as with the regular screening
breast-MRI protocol.
In conclusion, our study
suggests that with the “abbreviated breast MRI” approach introduced by us, screening
breast-MRI is feasible without compromise on sensitivity and specificity
compared with the regular full diagnostic MRI protocol. Abbreviated breast-MRI
screening could thus be used to open up the opportunity for “batch MRI
screening” according to the model of mammographic screening, and pave the
ground for a broader use of MRI for screening.
Acknowledgements
No acknowledgement found.References
Kuhl CK, Schrading S, Strobel K, Schild HH, Hilgers RD, Bieling HB.
Abbreviated breast magnetic resonance imaging (MRI): first postcontrast
subtracted images and maximum-intensity projection-a novel approach to breast
cancer screening with MRI. J Clin Oncol. 2014 Aug 1;32(22):2304-10. doi:
10.1200/JCO.2013.52.5386. Epub 2014 Jun 23. PubMed PMID: 24958821.
Mango VL, Morris EA, David Dershaw D, Abramson A, Fry C, Moskowitz CS, Hughes
M, Kaplan J, Jochelson MS. Abbreviated protocol for breast MRI: are multiple
sequences needed for cancer detection? Eur J Radiol. 2015 Jan;84(1):65-70. doi:
10.1016/j.ejrad.2014.10.004. Epub 2014 Oct 16. PubMed PMID: 25454099.