Mammogram vs MRI

[AlaskaAngel]

NEW YORK (Reuters Health) - Magnetic resonance imaging (MRI) is "significantly more sensitive" than mammography in detecting multiple malignant foci in fibroglandular or dense breasts but not in fatty breasts, according to findings from The Italian Trial for Breast MRI in Multifocal/Multicentric Cancer published in the October issue of the American Journal of Roentgenology.

Dr. Francesco Sardanelli from the Istituto Policlinico San Donato in Milan and colleagues compared the sensitivity of MRI versus mammography for detecting additional malignant lesions in 90 women with breast cancer scheduled to undergo mastectomy (9 bilateral, 99 breasts).

Additional malignant lesions were detected more often by MRI than by mammography (152 vs 124). Pathologic examination of the whole excised breast -- the gold standard -- detected 188 additional malignancies.

According to Dr. Sardanelli, the malignancies that were missed by mammography were "significantly larger and more aggressive (70% were invasive cancers) overall than the malignant areas that were missed by MR."

MRI was most useful in women with dense breast tissue. In fibroglandular or dense breasts, the sensitivity was 81% for MRI versus 60% for mammography.

However, false-positive results remain a problem for both techniques, which have a "relatively low" positive predictive value, the authors report. The overall positive predictive value of 68% for MRI was not significantly different from the positive predictive value of 76% for mammography.

Previous studies have shown that up to 42% of women diagnosed with breast cancer in one breast have at least one other malignant lesion in the same breast. It's important to identify these other malignant areas to determine the best course of treatment, the authors note.

Based on the current findings, Dr. Sardanelli and colleagues believe that it would be worthwhile to perform a "dynamic MRI examination before treatment planning in patients with a nonfatty breast pattern."

The findings of the current study support those of several previous studies showing that MRI is more sensitive than mammography in the detection of breast cancer. (see Reuters Health reports September 15 and July 28, 2004, among others).

Am J Roentgenol 2004;183:1149-1157