Preoperative mapping of cortical motor function: prospective comparison of functional magnetic resonance imaging and [15O]-H2O-positron emission tomography in the same co-ordinate system.
BACKGROUND
Two of the most widely accepted approaches to map eloquent cortical areas preoperatively are positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). As yet, no study has compared these two modalities within the same frame of reference in tumour patients.


OBJECTIVE
We employed [15O]-H2O-PET and fMRI in patients undergoing presurgical evaluation and compared the results with those obtained by direct electrical cortical stimulation (DECS).


METHODS
Twenty-five patients with tumours of different aetiology near the central region were investigated. fMRI and PET were processed using the same methods, i.e. statistical parametric mapping (SPM) without anatomical normalization, and transformed into the same frame of reference.


RESULTS
fMRI activity was found in more cranial and lateral sections, i.e. closer to the brain surface, in comparison with PET, which demonstrated parenchymal activation. The mean localization difference between fMRI and PET was 8.1 +/- 4.6 mm (range, 2-18 mm). fMRI and [15O]-H2O-PET could reliably identify the central sulcus, as demonstrated by DECS.


CONCLUSIONS
fMRI and [15O]-H2O-PET demonstrate comparable results and are sensitive and reliable tools to map the central region, especially in cases of infiltrating brain tumours. However, fMRI is more prone to artefacts, such as the visualization of draining veins, which may explain the more cranial and lateral activation visualized by fMRI, whereas PET depicts capillary perfusion changes and therefore shows activation closer to the parenchyma.
Reinges
Marcus H T
MH
Department of Neurosurgery, University Hospital Aachen, Germany. m.reinges@web.de
Krings
Timo
T
Meyer
Philipp T
PT
Schreckenberger
Mathias
M
Rohde
Veit
V
Weidemann
Jürgen
J
Sabri
Osama
O
Mulders
Edith J M
EJ
Buell
Udalrich
U
Thron
Armin
A
Gilsbach
Joachim M
JM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000601:surgery*; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D010104:Oxygen Radioisotopes; D019990:Perioperative Care / Q000379:methods; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014867:Water
D010104:Oxygen Radioisotopes; D019275:Radiopharmaceuticals; D014867:Water