[MR mammography at 0.5 tesla. I. Comparison of image quality and sensitivity of MR mammography at 0.5 and 1.5 T].
OBJECTIVE
To determine whether dynamic MR mammography is possible on midfield systems without loss of diagnostic sensitivity when compared to the standard highfield technique.


METHODS
42 consecutive patients were examined twice: Once using the standard dynamic 2D gradient echo technique at 1.5 T; a second examination was performed on a 0.5 T system. For the midfield examinations a 3D sequence with optimized T1 contrast was used to compensate for the shorter T1 relaxation times at 0.5 T. Subtraction images were calculated to improve detectability of enhancing lesions.


RESULTS
Image quality was comparable on both systems. Mean enhancement of lesions was higher at 0.5 T/3D as compared to 1.5 T/2D (161% versus 112%). In malignant lesions, enhancement at 0.5 T/3D surpassed that at 1.5 T/2D in 88% of cases; average maximum signal intensity increase of cancers was significantly higher at 0.5 T/3D as compared to 1.5 T/2D (183% versus 108% relative to baseline). One satellite lesion of a recurrent carcinoma was detected on the 0.5 T/3D images only.


CONCLUSIONS
A 3D gradient echo pulse sequence can be used to compensate for the T1 shortening effect of the lower field strength. With a 3D sequence, sensitivity of MRM at 0.5 T is even superior to that of the standard 2D highfield technique.
Kuhl
C K
CK
Radiologische Universitätsklinik, Rheinische Friedrich-Wilhelms-Universität, Bonn.
Kreft
B P
BP
Hauswirth
A
A
Elevelt
A
A
Steudel
A
A
Reiser
M
M
Schild
H H
HH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology*; D001941:Breast Diseases / Q000175:diagnosis*; D001943:Breast Neoplasms / Q000175:diagnosis; D002278:Carcinoma in Situ / Q000175:diagnosis; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis; D003937:Diagnosis, Differential; D017352:Echo-Planar Imaging; D005069:Evaluation Studies as Topic; D005260:Female; D018226:Fibroadenoma / Q000175:diagnosis; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D012680:Sensitivity and Specificity
MR-Mammographie bei 0.5 Tesla. Teil I: Vergleich von Bildqualität und Sensitivität der MR-Mammographie bei 0.5 und 1.5 T.