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55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

25. bis 28.04.2004, Köln

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Prospective comparison of functional MRI and [15O]-H2O-PET in the same coordinate system for preoperative mapping of cortical motor function

Prospektiver Vergleich von funktioneller MRT und [15O]-H2O-PET im gleichen Koordinatensystem zum präoperativen Mapping des Motorkortex

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Deutsche Gesellschaft für Neurochirurgie. Ungarische Gesellschaft für Neurochirurgie. 55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie. Köln, 25.-28.04.2004. Düsseldorf, Köln: German Medical Science; 2004. DocMO.06.04

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/dgnc2004/04dgnc0065.shtml

Published: April 23, 2004

© 2004 Reinges et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

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Objective

In patients with mass lesions near eloquent cortical areas, different preoperative mapping techniques can be used. Two of the most widely accepted approaches include positron emission tomography (PET) and functional MRI (fMRI). Up to now, no study has compared these two modalities within the same frame of reference in tumor patients. Thus, we employed [15O]-H2O-PET and fMRI in the same patients undergoing presurgical evaluation and compared the imaging results to those obtained by direct electrical cortical stimulation (DECS) to decide which method demonstrates more localization accuracy.

Methods

Twenty-five patients with tumors of different etiology near the central region were investigated. FMRI was performed using a T2*-weighted gradient-echo BOLD sequence at 1.5 T, PET was performed after injection of the cerebral blood flow tracer [15O]-H2O (500 MBq) under rest and activation conditions. DECS was performed in all patients with recordings of muscles primarily involved in the investigated tasks. Both, the fMRI and PET data from each patient were processed using the same methods, i.e. statistical parametric mapping (SPM) without anatomical normalization. After transforming fMRI and PET data into the same frame of reference (SPM coordinate system), the distance between activation maxima visualized by both methods in this 3D coordinate system was assessed.

Results

In 24 of 25 patients it was possible to compare fMRI, PET, and DECS. In all of these patients the cortical localization of the hand motor area was reliably and with a high statistical significance visualized. FMRI activity was found in more cranial and lateral sections, i.e. closer to the brain surface, in comparison to PET, that demonstrated activation clusters deep in the parenchyma in 17 of 24 patients (71%). The mean localization difference between fMRI and PET was 8.1 ± 4.6 mm (range: 2 - 18 mm).

Conclusions

FMRI and [15O]-H2O-PET demonstrate comparable results, both methods are therefore sensitive and reliable tools to map the central region, especially in cases of infiltrating brain tumors as demonstrated by DECS. The more cranial and lateral activation visualized by fMRI most likely reflects blood flow changes within a large draining vein while PET depicts more capillary perfusion changes within the parenchyma.