Screening for cerebral metastases with FDG PET in patients undergoing whole-body staging of non-central nervous system malignancy.
OBJECTIVE
To compare fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) with the current standard, magnetic resonance (MR) imaging, to determine the sensitivity and specificity of FDG PET for detection of cerebral metastases and to determine the factors that may affect lesion conspicuity.


METHODS
Forty patients underwent brain PET and contrast material-enhanced brain MR imaging, with a maximum of 30 days between examinations. PET and MR images were each retrospectively reviewed by two independent readers who were blinded to the clinical history and results of the other technique. Presence of metastatic disease was recorded for each modality. Sensitivity and specificity of FDG PET were determined with MR imaging as the standard. Statistical analysis was performed with the Fisher exact test and the logistic regression model.


RESULTS
Sixteen patients had cerebral metastases at MR imaging, and in 12 of these, PET scans were interpreted as showing metastatic disease (in four, scans were false-negative). Twenty-four patients had no cerebral metastases at MR imaging, and 20 of these had PET scans interpreted as normal (in four, scans were false-positive). For identification of patients with cerebral metastases, FDG PET had a sensitivity of 75% (12 of 16) and a specificity of 83% (20 of 24). Thirty-eight metastatic lesions were seen at MR imaging; 23 (61%) of these were identified at PET. Size was a statistically significant factor that influenced lesion detection at PET (P <.001).


CONCLUSIONS
Only 61% of metastatic lesions in the brain were identified at PET. In particular, detection of small lesions was difficult.
Rohren
Eric M
EM
Department of Radiology, Duke University Medical Center, Durham, NC, USA. Rohren.Eric@mayo.edu
Provenzale
James M
JM
Barboriak
Daniel P
DP
Coleman
R Edward
RE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary*; D005189:False Positive Reactions; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D014055:Tomography, Emission-Computed
D019788:Fluorodeoxyglucose F18