Use of contrast-enhanced fluid attenuated inversion recovery magnetic resonance imaging in the diagnosis of metastatic brain tumors

Purpose: To investigate the value of contrast-enhanced fluid attenuated inversion recovery (FLAIR) imaging in the diagnosis of metastatic brain tumors. Methods: Spin echo (SE) T-2-weighted images, noncontrast and contrast-enhanced T-1-weighted SE images, and noncontrast and contrast-enhanced FLAIR images from 32 patients with brain metastases were reviewed to compare lesion detectability on contrast-enhanced FLAIR versus contrast-enhanced T-1-weighted SE imaging, and on contrast-enhanced FLAIR versus noncontrast SE T-2-weighted imaging. Results: All 32 patients exhibited enhancing lesions on contrast-enhanced FLAIR imaging. Of the 145 lesions detected by any sequence, 19 were not detected on the contrast-enhanced FLAIR images (13.1%). There was no significant difference in lesion detectability between FLAIR and T-1-weighted sequences. In 21 of the 32 patients (66%), the contrast-enhanced FLAIR images showed the tumor margin more clearly than did the contrast-enhanced T-1-weighted images. In each patient, contrast-enhanced FLAIR images demonstrated accompanying edema better than did T-2-weighted SE images. Conclusion: Contrast-enhanced FLAIR images are inferior to contrast-enhanced T-1-weighted SE images for detection of brain metastases, but remain useful for depicting both the peritumoral edema and the tumor margin on a single image.