2005 Proceedings - ASNR

Posters
p < 0.05 level. The binormal receiver operating characteristic
(ROC) curves for rCBV values were constructed to distinguish
cutoff values.
RESULTS
The mean differences of rCBV values between low- (1.71 ±
0.59) and high-grade tumors (5.01 ± 1.03) (p < 0.000); highgrade
and metastases (2.45 ± 0.70) (p < 0.000); and lowgrade
and metastases (p < 0.002) were significant. No clear
cutoff value was present. The clear rCBV cutoff value of 1.9
for differentiation low- (1.44 ± 0.23) vs high-grade (4.88 ±
1.21) astrocytomas, 3.4 for differentiation low- (2.25 ± 0.73)
vs high-grade (5.28 ± 0.48) oligodendrogliomas, and 3.8 for
differentiation glioblastoma multiforme (5.72 ± 0.90) vs
metastases was detected with the sensitivity of 100%, the
specificity of 100%, and the accuracy of 100%. Although the
mean differences between anaplastic astrocytoma (4.04 ±
0.83) and anaplastic oligodendroglioma (p < 0.000);
anaplastic astrocytoma and metastases (p < 0.000); and lowgrade
astrocytoma and metastases (p < 0.05) were significant,
no clear cutoff value was detected for exact differentiation.
The rCBV values were correlated with degree of
malignancy (r = 0.869, P < 0.000) and with tumor type (r =
0.823, P < 0.000). The overall efficacy of rCBV calculation
was higher in grading of glial tumors than in differentiation
of high-grade glial tumors from metastases.
CONCLUSION
DSC perfusion imaging with rCBV calculation seemed quite
effective in both the grading of malignant glial brain tumors
and in the differentiation of high-grade glial tumors from
solitary intraaxial metastasis. The astrocytomas and oligodendrogliomas
have to be evaluated separately for exact
grading.
REFERENCES
1. Aronen HJ, Gazit IE, Louis DN, et al. Cerebral blood volume
maps of gliomas: comparison with tumor grade and histologic
findings. Radiology 1994;191:41-51
2. Lev MH, Ozsunar Y, Henson JW, et al. Glial tumor grading
and outcome prediction using dynamic spin-echo MR susceptibility
mapping compared with conventional contrastenhanced
MR: confounding effect of elevated rCBV of oligodendrogliomas
[corrected]. AJNR Am J Neuroradiol
2004;25:214-221
KEY WORDS: Brain-neoplasm, perfusion imaging, relative
cerebral blood volume
Poster 36
Correlation of MR Perfusion Imaging and Vessel
Tortuosity Parameters in Assessment of Intracranial
Neoplasms
Parikh, A. H. · Smith, J. K. · Ewend, M. · Bullitt, E.
University of North Carolina at Chapel Hill
Chapel Hill, NC
PURPOSE
To determine the correlation between tumor vessel tortuosity
as measured from vessels extracted from MR angiograms
(MRA) and perfusion parameters of cerebral blood flow
(CBF) and cerebral blood volume (CBV) in intracranial neo-
304
plasms. We hypothesized that tumor blood vessel tortuosity
measures and perfusion measures would be correlated, since
both are increased by tumor angiogenesis.
MATERIALS & METHODS
Eighteen patients with 19 cerebral neoplasms were evaluated
with conventional MR imaging and dynamic contrastenhanced
T2-weighted perfusion MR imaging. Both benign
and malignant lesions were included, as were hyper and
hypovascular tumors. Regions of interest were plotted within
the tumor area to locate foci of maximum CBV and CBF.
Cerebral blood volume and CBF measurements were recorded
also in contralateral normal appearing white matter to calculate
relative CBV (rCBV) and relative CBF (rCBF). Vessel
tortuosity analyses were conducted upon vessels segmented
from MRA images of the same patients using two tortuosity
descriptors (SOAM and ICM) which have been demonstrated
previously to have efficacy in separating benign from
malignant disease. Linear regression analyses were conducted
to determine if correlations exist between CBV or CBF
and the two tortuosity measurements.
RESULTS
For the overall set of tumors, no significant correlations were
found between flow or volume measures and the tortuosity
measures. However, when the 7 glioblastoma multiforme
tumors were examined as a subgroup, the following significant
correlations were found: rCBV and SOAM (R 2 = 0.799),
rCBV and ICM (R 2 = 0.214).
CONCLUSION
Our results demonstrate that MR perfusion imaging data do
not correlate significantly with vessel tortuosity parameters
as determined from the larger vessels seen by MRA.
However, for subgroups of a particular tumor type such as
GBM, there may be significant correlations. It appears that
perfusion and tortuosity data may provide independently
useful data in the assessment of cerebral neoplasms.
KEY WORDS: Intracranial neoplasm, MR perfusion imaging,
vessel tortuosity
Poster 37
Relative Cerebral Blood Volume Ratios in the following
of Posttherapeutic Glial Tumors
Bulakbasi, N. · Ilkbahar, S. · Guvenc, I. · Kocaoglu, M. ·
Tayfun, C. · Ucoz, T.
Gulhane Military Medical Academy
Ankara, TURKEY
PURPOSE
We aimed to determine the role of dynamic contrastenhanced
perfusion MR imaging, using normalized relative
blood volume (rCBV) in the evaluation of postoperative and
radiotherapy-related changes of patients with glial tumors.
MATERIALS & METHODS
Twenty-four patients (13 male, 11 female, age range from 21
to 67 years, mean 36.3 years) treated by surgery and radiotherapy
with the diagnosis of glial tumors were included in
this study. MR imaging was performed using a 1.5 T superconductive
magnet with standard head coils. Conventional