title: An imaging protocol for dynamic contrast-enhanced breast MRI with 3.0T: using sagittal sequence interleaved between axial sequences.
abstract: BACKGROUND
  B1 transmission-field inhomogeneity has been reported at 3.0 Tesla (T) breast imaging. Enhancement measurements of breast cancers at 3.0T may be insufficient for some patients and improvements in imaging protocols are needed.
  
  
  OBJECTIVE
  To quantify B1 inhomogeneities in normal tissue and malignant masses at 3.0T breast MR imaging and to evaluate effect of an imaging protocol using an interleaved sagittal sequence in dynamic contrast-enhanced MRI (DCE-MRI).
  
  
  METHODS
  A total of 76 patients were included who underwent DCE-MRI of the breast at 3.0T with an imaging protocol consisting of 1st, 2nd, and 4-6th bilateral axial sequences, and 3rd and 7th unilateral sagittal sequences. Signal intensity (SI) of normal breast tissue was measured at nipple level in four bilateral locations (anterior, posterior, medial, and lateral). Mean whole breast and location specific SI were calculated and compared between right and left breast using a paired t-test. All malignant masses were classified into three groups according to tumor size on MRI (≤2 cm, 2-4 cm, >4 cm). SI of malignant masses was measured independently on axial and sagittal sequences. The axial-sagittal SI gap in each mass was calculated and difference between right and left breast was compared using the t test. Size of each malignant mass was compared with pathologic findings to assess performance of the imaging protocol.
  
  
  RESULTS
  SI of normal breast tissue were lower for the right breast (R-L difference, -91.9; P < 0.0001) and in all four locations (anterior, P < 0.01; posterior, P < 0.01; medial, P < 0.0001; lateral, P < 0.0001). SI of malignant masses were lower for the right breast among same size of the lesions (P < 0.0001), particularly < 4 cm (P < 0.0001). Decreased right to left difference in SI was produced with an interleaved sagittal sequence, as axial-sagittal gap of malignant masses was significant when tumor locates on the right side (P < 0.001). The concordance rate in predicting size of mass in this imaging protocol was 92.2%.
  
  
  CONCLUSIONS
  The interleaved sagittal sequence is helpful to adjust reduced SI of malignant masses on right breast at 3.0T. This imaging protocol is clinically applicable by adding a single sequence during DCE-MRI of the breast.
authors.affiliation: Department of Radiology, Ewha Womans University School of Medicine, Seoul.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Park
authors.forename: Jee Eun
authors.initials: JE
authors.lastname: Lee
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Hwang
authors.forename: Eun Suk
authors.initials: ES
authors.lastname: Cha
mesh_terms: D000704:Analysis of Variance; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology*; D003287:Contrast Media / Q000008:administration & dosage; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009361:Neoplasm Invasiveness
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA
keywords: 3.0T MRI; breast cancer; dynamic enhancement; interleaved sagittal; protocol