脑瘤灌注CT不同层厚CBV与rCBV测量的可重复性研究(英文)

Objective:To assess inter-and intraobserver reproducibility for measuring perfusion CT derived cerebral blood volume (CBV) and relative cerebral blood volume (rCBV) with different slice thickness in patients with brain neoplasms. Meth- ods: Three independent observers who were blinded to the histopathologic diagnosis performed perfusion derived CBV and rCBV measurements with 5 mm and 10 mm slice thickness in 52 patients with various cerebral neoplasms. The results of the measurements with different slice thickness were compared. Calculation of coefficient of variation (CV), and relative paired difference of the measurements were used to determine the levels of inter- and intraobserver reproducibility. Results: The differences of CBV and rCBV measurements between different slice thickness groups were statistically significant (P < 0.05) respectively in observer 2, and were not significant in the other two observers (P > 0.05). For the same slice thickness, both the difference of CBV and rCBV measurements among the three observers were not statistically significant. Interobserver CV and relative paired difference of the measurements with 10 mm slice thickness group were slightly lower than those of 5 mm slice thickness group. Interobserver CV and relative paired difference of CBV group were slightly lower than those of rCBV group. The intraobserver differences of CBV and rCBV in 10 mm slice thickness group were statistically significant for observer 2 respectively. No other intraobserver differences of measurements were statistically significant. CV and relative paired difference of intraobserver CBV and rCBV measurements for observer 2 were significantly higher than for the other two observers. Conclusion: High reproducibility of CBV and rCBV measurements was acquired with the two different slice thickness. Suitable training may be helpful to maintain a high level of consistency for measurements.

Experimental study on angiogenesis in rabbit VX_2 brain tumor using perfusion CT

Objective:To study the perfusion CT features of rabbit VX2 brain tumor with correlation to MVD and VEGF,and to validate perfusion CT for reflection of tumor angiogenesis.Methods:Rabbit VX2 brain tumor model was established by injection of 100 μL viable tumor cells(107/mL)through a 2 mm-hole 5 mm to the right of the sagittal suture and 5 mm posterior to the coronal suture bored by dental drill.MRI was performed every 2 days after seven days of implantation to evaluate the growth of the tumor.Twenty New Zealand White rabbits with tumor size over 3 mm in diameter were randomly divided into 2 groups according to the tumor growth time with those less than 3 weeks as group 1 and those more than 3 weeks as group 2,and perfusion CT were performed accordingly.CT measurements of BV,BF and PS from tumor,peritumor and contralateral normal tissue regions were obtained.After that the animals were sacrificed and 2% Evans blue(2 mL/kg)was given intravenously in 16 of these animals 1 h prior to sacrifice to detect breakdown of the blood brain barrier.VEGF and MVD were evaluated in im-munohistochemical examination of the specimens.Results:Tumor had significantly higher BV,BF and PS(P=0.000)than peritumor and normal tissue region.Tumor BV,BF and MVD in group 2 were significantly higher than that in group 1(P<0.01).Significant linear correlation was found between MVD and BV(r=0.915,P=0.000),MVD and BF(r=0.901,P=0.000),and MVD and PS(r=0.459,P=0.042).We also found a rank correlation between PS and blue stain of tumor(rs=0.861,P=0.000).Conclu-sion:Perfusion CT can distinguish tumor from peritumor and normal tissue clearly,reflect tumor angiogenesis accurately,and provide useful information for the evaluation of brain tumor.