Contrast-enhanced breast MR imaging of claustrophobic or oversized patients using an open low-field magnet.
OBJECTIVE
A number of women who should undergo magnetic resonance (MR) imaging of the breast cannot use this diagnostic tool due to claustrophobia or excessive body size for the restricted confines of standard closed MR systems. Our aim was to evaluate the performance of open low-field magnet breast MR imaging in such patients using a high-relaxivity contrast agent.


METHODS
Of 397 consecutive patients undergoing breast MR imaging, 379 (95.5%) were studied at 1.5 T. Due to claustrophobia (n=15) or large body size (n=3), 18 patients (4.5%) were studied on a 0.2-T open magnet using a body coil. A 3D dynamic T1-weighted gradient-echo 94-s sequence was acquired with intravenous injection of gadobenate dimeglumine (0.1 mmol/kg). The standard of reference was pathological examination for 16 lesions classified with a maximal Breast Imaging Reporting and Data System (BI-RADS) score from 3 to 5, fine-needle aspiration cytology and >or=2-year follow-up for two lesions classified as BI-RADS 3, and >or=2-years follow-up for five lesions classified as BI-RADS 2.


RESULTS
Diagnostic MR image quality was achieved for 20/23 lesions in 15/18 patients. Three lesions (two invasive cancers and a cyst) were not assessed due to patient movement and considered as two false negatives and one false positive. Thus, an 86% sensitivity [13/15; 95% confidence interval (CI): 70%-100%], an 87% specificity (7/8; 95% CI: 65%-100%) and an 87% accuracy (20/23; 95% CI: 73%-100%) were obtained. The intraclass correlation coefficient between MR and pathologic lesion size was 0.845.


CONCLUSIONS
In claustrophobic or oversized patients, open low-field breast MR with gadobenate dimeglumine yields good diagnostic performance.
Calabrese
M
M
Unit of Breast Imaging, University of Genoa and San Martino Hospital, Largo Rosanna Benzi 10, 16132, Genoa, Italy.
Brizzi
D
D
Carbonaro
L
L
Chiaramondia
M
M
Kirchin
M A
MA
Sardanelli
F
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media; D004867:Equipment Design; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008536:Meglumine / Q000031:analogs & derivatives*; D008875:Middle Aged; D009942:Organometallic Compounds; D050177:Overweight; D010698:Phobic Disorders / Q000150:complications*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012680:Sensitivity and Specificity
D003287:Contrast Media; D009942:Organometallic Compounds; C064572:gadobenic acid; D008536:Meglumine