Variable spatiotemporal resolution three-dimensional Dixon sequence for rapid dynamic contrast-enhanced breast MRI.
OBJECTIVE
To investigate a new variable spatiotemporal resolution dynamic contrast-enhanced (DCE) MRI method termed DIfferential Subsampling with Cartesian Ordering (DISCO), for imaging of breast cancer.


METHODS
DISCO combines variable density, pseudorandom k-space segmentation and two-point Dixon fat-water separation for high spatiotemporal resolution breast DCE MRI. During the contrast wash-in phase, view sharing is used to achieve high temporal resolution. Forty patients referred for breast MRI were imaged, 26 using the proposed DISCO sequence and 14 using a conventional low-spatial-resolution dynamic sequence (VIBRANT-FLEX) on a 3 Tesla scanner. DISCO dynamic images from 14 patients were compared with VIBRANT-FLEX images from 14 other patients. The image quality assessed by radiologist image ranking in a blinded manner, and the temporal characteristics of the two sequences were compared.


RESULTS
A spatial resolution of 1.1 × 1.1 × 1.2 mm(3) (160 slices, 28 cm field of view) was achieved with axial bilateral coverage in 120 s. Dynamic images with ∼ 9 s effective temporal resolution were generated during the 2-min contrast wash-in phase. The image quality of DISCO dynamic images ranked significantly higher than low spatial resolution VIBRANT-FLEX images (19.5 versus 9.5, Mann-Whitney U-test P = 0.00914), with no significant differences in the maximum slope of aortic enhancement.


CONCLUSIONS
DISCO is a promising variable-spatiotemporal-resolution imaging sequence for capturing the dynamics of rapidly enhancing tumors as well as structural features postcontrast. A near 1-mm isotropic spatial resolution was achieved with postcontrast static phase images in 120 s and dynamic phase images acquired in 9 s per phase.
Department of Radiology, Stanford, California, USA.
Manojkumar
M
Saranathan
Dan W
DW
Rettmann
Brian A
BA
Hargreaves
Jafi A
JA
Lipson
Bruce L
BL
Daniel
D000328:Adult; D000368:Aged; D000465:Algorithms; D001943:Breast Neoplasms / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D016037:Single-Blind Method; D062211:Spatio-Temporal Analysis
D003287:Contrast Media
Dixon fat-water separation; dynamic contrast-enhanced breast MRI; time resolved imaging; variable spatiotemporal resolution