Usefulness of contrast-enhanced FLAIR MRI in the diagnosis of intracranial tumors

Objective: To determine the clinical utility of Gadolinium-enhanced fast fluid-attenuated inversion-recovery(FLAIR) MR imaging in the diagnosis of intracranial tumors. Methods: One hundred and four consecutive patients with intracranial tumors referred for gadolinium-enhanced brain MR imaging including FLAIR and T1-weighted MR imaging pre- and post- administration of Gd-DTPA. The contrast-enhanced FLAIR (CE FLAIR) and T1-weighted spin-echo MR images were evaluated independently by two radiologists for the number of examinations with one or more enhancing lesions, the number and location of enhancing lesions per examinations, signal-to-noise ratio (CNR) and contrast-enhancement ratio (CER) of lesions, size and extent of enhancing lesions. Results: In 98 of 104 patients, we saw enhancing lesions both on the FLAIR and T1W images. More lesions were seen on enhanced T1WI (n=120) than those on the enhanced FLAIR sequence (n=117), which did not show statistical significance between the two sequences (P>0.05). Four lesions were only revealed on CE FLAIR whereas 7 lesions were only found on postcontrast T1WI. Enhancing lesions located in cerebral hemisphere or the forth ventricle was revealed much more on T1WI than that on CE FLAIR. However, postcontrast fast FLAIR images may be useful in detecting superficial abnormalities and those located in sulcus or lateral ventricle. The enhancement degree of enhanced T1WI was much more intense than that of CE FLAIR (P<0.01). There were no statistical significance in SNR (P>0.05) and statistical significance in GWC, CNR and CER (P<0.05) of the both sequences. The size and extent of lesions on CE FLAIR images were significantly larger than that on postcontrast T1WI (P<0.01). Conclusion: Gadolinium-enhanced FLAIR and T1-weighted spin-echo MR images may complement each other in detecting intracranial tumors and the CE FLAIR should be selected to the routine MRI sequence. (authors)