1H MR spectroscopy and diffusion-weighted imaging of the breast: are they useful tools for characterizing breast lesions before biopsy?
OBJECTIVE
The objective of our study was to determine whether proton ((1)H) MR spectroscopy (MRS) and diffusion-weighted imaging might be useful tools for characterizing breast lesions before biopsy.


METHODS
Single-voxel (1)H MRS and diffusion-weighted imaging were performed in 171 suspicious or highly suspicious lesions. Using the residual water signal as a reference (4.7 ppm), a choline peak at 3.22-3.23 ppm was defined as malignant. If a high-signal-intensity lesion was detected in high-b-value (b = 1,500 s/mm(2)) images, that lesion was defined as positive for malignancy. Among the patients with positive results on diffusion-weighted imaging, the apparent diffusion coefficient (ADC) values of the mass or focus were calculated from two different gradient factors (b(1) = 500 s/mm(2) and b(2) = 1,500 s/mm(2)).


RESULTS
The diagnostic sensitivity and specificity of (1)H MRS were 44% (40/91) and 85% (68/80), respectively (p < 0.001). If (1)H MRS was applied for mass lesions larger than 15 mm, the diagnostic sensitivity and specificity were 82% (28/34) and 69% (11/16), respectively. Of the high-b-value images, 24 benign lesions and eight nonmass ductal carcinoma in situ were visually negative. With the use of a cutoff ADC value of 1.13 x 10(-3) mm(2)/s, a specificity of 67% (43/64) and sensitivity of 97% (61/63) was obtained on diffusion-weighted imaging.


CONCLUSIONS
(1)H MRS was useful for characterizing breast lesions measuring 15 mm or larger, and diffusion-weighted imaging was useful for characterizing lesions of any size. However, these two techniques still have potential pitfalls in relation to the diagnosis of nonmass breast lesions.
Tozaki
Mitsuhiro
M
Division of Diagnostic Imaging, Breast Center, Kameda Medical Center, 929 Higashi-cho, Kamogawa, Chiba 296-8602, Japan. e-tozaki@keh.biglobe.ne.jp
Fukuma
Eisuke
E
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D003287:Contrast Media; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D003287:Contrast Media; D019786:Gadolinium DTPA