Perfusion MRI as a neurosurgical tool for improved targeting in stereotactic tumor biopsies.
OBJECTIVE
Stereotactic biopsies are subject to sampling errors (essentially due to target selection). The presence of contrast enhancement is not a reliable marker of malignancy. The goal of the present study was to determine whether perfusion-weighted imaging can improve target selection in stereotactic biopsies.


METHODS
We studied 21 consecutive stereotactic biopsies between June 2009 and March 2010. Perfusion-weighted magnetic resonance imaging (MRI) was integrated into our neuronavigator. Perfusion-weighted imaging was used as an adjunct to conventional MRI data for target determination. Conventional MRI alone was used to determine the trajectory.


RESULTS
We found a linear correlation between regional cerebral blood volume (rCBV) and vessel density (number of vessels per mm(2); R = 0.64; p < 0.001). Perfusion-weighted imaging facilitated target determination in 11 cases (52.4%), all of which were histopathologically diagnosed as glial tumors. For glial tumors, which presented with contrast enhancement, perfusion-weighted imaging identified a more precisely delimited target in 9 cases, a different target in 1 case, and exactly the same target in 1 other case. In all cases, perfusion-selected sampling provided information on cellular features and tumor grading. rCBV was significantly associated with grading (p < 0.01), endothelial proliferation (p < 0.01), and vessel density (p < 0.01). For lesions with rCBV values ≤1, perfusion-weighted MRI did not help to determine the target but was useful for surgical management.


CONCLUSIONS
For stereotactic biopsies, targeting based on perfusion-weighted imaging is a feasible method for reducing the sampling error and improving target selection in the histopathological diagnosis of tumors with high rCBVs.
Department of Neurosurgery, Amiens University Hospital, Amiens, France. lefrancm@me.com
M
M
Lefranc
P
P
Monet
C
C
Desenclos
J
J
Peltier
A
A
Fichten
P
P
Toussaint
H
H
Sevestre
H
H
Deramond
D
D
Le Gars
D001706:Biopsy / Q000379:methods; D001921:Brain / Q000473:pathology / Q000601:surgery; D001932:Brain Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D005910:Glioma / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008223:Lymphoma / Q000473:pathology* / Q000601:surgery; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D013238:Stereotaxic Techniques