Article
Stereotactic coregistration of 201 Thallium Single Photon Emission Tomography and Magnetic Resonance Imaging applied to brain tumor biopsies
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Published: | May 4, 2005 |
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Outline
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Objective
The aim of the present study was to determine the clinical feasibility of integration of stereotactic single photon emission tomography (sSPECT) with 201-labeled thallium (201Tl) in the stereotactic magnet resonance tomography (sMRI) based planning of brain tumor biopsy. Furthermore, its predictive value in comparison with the corresponding histologically determined metabolic activity should be analyzed.
Methods
Ten patients underwent combined 201Tl-SPECT- and MRI-guided stereotactic biopsy of intracranial lesions according to a previously described technique. An area of abnormal 201Tl-uptake was used to guide the stereotactic biopsy trajectory. Several samples were taken along the trajectory above and under the target. Extensive histological diagnosis (tumor grade, mitotic index (MI), Ki67 index (KiI)) and thallium index (201TI-Index) were obtained for all samples and compared statistically.
Results
Combined 201Tl-sSPECT and sMRI-guided biopsy could be performed in all patients. KiI, MI and tumor grade are significantly correlated. No significant correlation was found between MI and KiI compared to the 201TI-Index of all patients. A trend to significance exists between tumor grade and 201TI-Index (p=0.059). 201TI-Index for grade III tumors (3.27±1.89) is significantly different from the one for grade IV tumors (4.34±1.29). The sample position on the trajectory was correlated with the MI. In four of ten cases, a tumor grade variation along the trajectory could be observed. In all patients, the highest proliferative activity corresponded to the target or to a sample 5 to 10 mm away from it.
Conclusions
These results support the view that 201Tl-SPECT may contribute to the successful management of brain tumor patients requiring stereotactic biopsy without any significant increase in discomfort or morbidity related to the technique. The development of similar techniques integrating sSPECT data in the planning of stereotactic biopsy should be considered by centers performing stereotactic surgery and having access to SPECT technology. In the long-term this technique could become a support for focusing gene therapy and cell transfer.