title: Overcoming limitations in diffusion-weighted MRI of breast by spatio-temporal encoding.
abstract: OBJECTIVE
  Evaluating the usefulness of diffusion-weighted spatio-temporal encoding (SPEN) methods to provide quantitative apparent diffusion coefficient (ADC)-based characterizations of healthy and malignant human breast tissues, in comparison with results obtained using techniques based on spin-echo echo planar imaging (SE-EPI).
  
  
  METHODS
  Twelve healthy volunteers and six breast cancer patients were scanned at 3T using scanner-supplied diffusion-weighted imaging EPI sequences, as well as two fully refocused SPEN variants programmed in-house. Suitable codes were written to process the data, including calculations of the actual b-values and retrieval of the ADC maps.
  
  
  RESULTS
  Systematically better images were afforded by the SPEN scans, with negligible geometrical distortions and markedly weaker ghosting artifacts arising from either fat tissues or from strongly emitting areas such as cysts. SPEN-derived images provided improved characterizations of the fibroglandular tissues and of the lesions' contours. When translated into the calculation of the ADC maps, there were no significant differences between the mean ADCs derived from SPEN and SE-EPI: if reliable images were available, both techniques showed that ADCs decreased by nearly two-fold in the malignant lesion areas.
  
  
  CONCLUSIONS
  SPEN-based sequences yielded diffusion-weighted breast images with minimal artifacts and distortions, enabling the calculation of improved ADC maps and the identification of decreased ADCs in malignant regions.
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Eddy
authors.initials: E
authors.lastname: Solomon
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.|Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Noam
authors.initials: N
authors.lastname: Nissan
authors.affiliation: Unit of Biological Services, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Edna
authors.initials: E
authors.lastname: Furman-Haran
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Amir
authors.initials: A
authors.lastname: Seginer
authors.affiliation: Department of Radiology, Meir Hospital, Kfar Saba, Israel.
authors.forename: Myra
authors.initials: M
authors.lastname: Shapiro-Feinberg
authors.affiliation: Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Hadassa
authors.initials: H
authors.lastname: Degani
authors.affiliation: Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Lucio
authors.initials: L
authors.lastname: Frydman
mesh_terms: D000328:Adult; D001940:Breast / Q000033:anatomy & histology*; D001943:Breast Neoplasms / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008875:Middle Aged; D012680:Sensitivity and Specificity
keywords: apparent diffusion coefficients; breast MRI; breast cancer; diffusion-weighted imaging; spatiotemporal encoding