MR imaging of leptomeningeal metastases: comparison of three sequences.
OBJECTIVE
Recent work has shown that fluid-attenuated inversion recovery (FLAIR) imaging with contrast enhancement is highly sensitive for detecting subarachnoid space disease. We hypothesized that contrast-enhanced FLAIR imaging has superior sensitivity to contrast-enhanced T1-weighted MR imaging in detecting leptomeningeal metastases.


METHODS
Sixty-eight patients referred for suspected leptomeningeal metastases underwent 74 MR imaging studies. The patients had either temporally related cytologic proof of leptomeningeal metastases or negative results of clinical follow-up confirming absence of leptomeningeal metastases. The MR imaging examinations included unenhanced and contrast-enhanced FLAIR images and contrast-enhanced T1-weighted MR images that were independently reviewed by two neuroradiologists blinded to the results of cytology. Each of the three sequences was reviewed individually and separately and was assigned a score of positive or negative for leptomeningeal metastases. Discrepancies were settled by consensus.


RESULTS
Of the 17 studies of patients with cytology-proven leptomeningeal metastases, two were positive based on unenhanced FLAIR images, seven were positive based on contrast-enhanced FLAIR images, and 10 were positive based on contrast-enhanced T1-weighted MR images. Of the 57 studies of patients without leptomeningeal metastases, 53 were negative based on unenhanced FLAIR images, 50 were negative based on contrast-enhanced FLAIR images, and 53 were negative based on contrast-enhanced T1-weighted MR images. The sensitivity and specificity of unenhanced FLAIR images for detecting leptomeningeal metastases were 12% (two of 17) and 93% (53 of 57), respectively. The sensitivity and specificity for contrast-enhanced FLAIR images for detecting leptomeningeal metastases were 41% (seven of 17) and 88% (50 of 57), respectively. The sensitivity and specificity of contrast-enhanced T1-weighted MR images for detecting leptomeningeal metastases were 59% (10 of 17) and 93% (53 of 57), respectively.


CONCLUSIONS
Contrast-enhanced fast FLAIR sequences are less sensitive than standard contrast-enhanced T1-weighted MR sequences in detecting intracranial neoplastic leptomeningeal disease.
Singh
Sanjay K
SK
Department of Diagnostic Radiology, The University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA.
Leeds
Norman E
NE
Ginsberg
Lawrence E
LE
D000293:Adolescent; D000328:Adult; D000368:Aged; D002555:Cerebrospinal Fluid / Q000166:cytology; D002648:Child; D003287:Contrast Media; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008577:Meningeal Neoplasms / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000556:secondary*; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity; D016037:Single-Blind Method
D003287:Contrast Media