Correlation of apparent diffusion coefficient with Ki-67 proliferation index in grading meningioma.
OBJECTIVE
A noninvasive method to predict aggressiveness of high-grade meningiomas would be desirable because it would help anticipate tumor recurrence and improve tumor management and the treatment outcomes. The Ki-67 protein is a marker of tumor proliferation, and apparent diffusion coefficient (ADC) is related to tumor cellularity. Therefore, we sought to determine whether there is a statistically significant correlation between ADC and Ki-67 values in meningiomas and whether ADC values can differentiate various meningioma subtypes.


METHODS
MRI examinations and histopathology of 68 surgically treated meningiomas were retrospectively reviewed. Mean ADC values were derived from diffusion imaging. Correlation coefficients were calculated for mean ADC and Ki-67 proliferation index values using linear regression. An independent unpaired Student t test was used to compare the ADC and Ki-67 proliferation index values from low-grade and more aggressive meningiomas.


RESULTS
A statistically significant inverse correlation was found between ADC and Ki-67 proliferation index for low-grade and aggressive meningiomas (r(2) = -0.33, p = 0.0039). ADC values (± SD) of low-grade meningiomas (0.84 ± 0.14 × 10(-3) mm(2)/s) and aggressive (atypical or anaplastic) meningiomas (0.75 ± 0.03 × 10(-3) mm(2)/s) were significantly different (p = 0.0495). Using an ADC cutoff value of 0.70 × 10(-3) mm(2)/s, the sensitivity for diagnosing aggressive meningiomas was 29%, specificity was 94%, positive predictive value was 67%, and negative predictive value was 75%.


CONCLUSIONS
ADC values correlate inversely with Ki-67 proliferation index and help differentiate low-grade from aggressive meningiomas.
1 Department of Radiology, Buffalo VA Medical Center, 3495 Bailey Ave, Buffalo, NY 14215.
Yi
Y
Tang
Sathish K
SK
Dundamadappa
Senthur
S
Thangasamy
Thomas
T
Flood
Richard
R
Moser
Thomas
T
Smith
Keith
K
Cauley
Deepak
D
Takhtani
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008577:Meningeal Neoplasms / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D008579:Meningioma / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D060787:Neoplasm Grading; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
D014408:Biomarkers, Tumor; D019394:Ki-67 Antigen