| Abstract |
Aim: The aim of our study was to evaluate the preoperative diagnostic power and
classification accuracy of perfusion parameters derived from whole brain volume
perfusion CT (VPCT) in patients with cerebral tumours.
Materials & Methods: Sixty‐three consecutive patients, with MRI findings suggestive
of cerebral lesions, were recruited prospectively in our series (31 male, 32 female;
mean age 55.6 ± 13.9 years). All patients underwent VPCT. VPCT was carried out by
using a 128 slice‐4D‐spiral CT scanner with a constant bidirectional movement of the
patient table. None of them has been treated either with biopsy or surgery prior to
study. Two readers independently evaluated VPCT data. Volumes of interest (VOIs)
were marked circumscript around the tumour according to maximum intensity
projection volumes, and then mapped automatically onto the cerebral blood volume
(CBV), flow (CBF) and permeability (Ktrans) perfusion datasets. A second VOI,
cortically pronounced, was placed in the contra lateral hemisphere in order to obtain
control values. Statistical analysis followed and correlations among perfusion values,
tumour grade, cerebral hemisphere and VOIs were evaluated. Moreover, the
diagnostic power of VPCT parameters, by means of positive and negative predictive
value, was analysed by Receiver Operating Characteristic curve analysis.
Results: Histopathological analysis revealed 32 high‐grade gliomas WHO III/IV, 18
low‐grade I/II, 6 primary cerebral lymphomas, 4 metastases and 3 tumour‐like
lesions. Our data analysis showed that high‐grade gliomas could be differentiated
from low‐grade gliomas due to the significant elevation in all the three perfusion
parameters. Lymphomas could be differentiated from low‐grade gliomas according
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to the remarkable increase in Ktrans, a finding, which is in keeping with the
histopathologic feature of blood‐brain barrier disturbance in lymphomas. Finally,
high‐grade gliomas proved to have significantly higher CBF and CBV values when
compared to lymphomas, probably due to neovascularisation. Primary cerebral
lymphomas though, presented with significantly higher Ktrans. Our results imply that
high‐grade gliomas are also characterised by blood‐brain barrier disruption, but to a
lesser grade than lymphomas. Ktrans proved to be the perfusion parameter with the
highest sensitivity, specificity and positive predictive value, for the pair‐wise
comparison between high‐grade and low‐grade gliomas. Finally, for the
differentiation between high‐grade and primary cerebral lymphomas, CBF and CBV
demonstrated the highest specificity and positive predictive value, identifying
preoperatively all the histopathologically proven high‐grade gliomas. Their NPV,
though, was much lower than that of Ktrans. 96% of the lesions with Ktrans value
less than 6.48mL/100mL/min proved to be high‐grade on histopathology.
Conclusion: As a conclusion, our data suggest that all the three perfusion parameters
play an important role in the preoperative classification of cerebral tumour entities
demonstrating a high rate of histopathologic correlation.
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Μελέτη και αξιολόγηση των παραμέτρων της περιοχικής αιματικής διήθησης (Perfusion) του εγκεφάλου, με χρήση πολυτομικού αξονικού τομογράφου 128 τόμων , σε ασθενείς με ενδοεγκεφαλικά νεοπλάσματα
