Value of introvoxel incoherent motion model in assessment of differentiation and blood supply of cervical cancer

Abstract

Objective To investigate the value of intravoxel incoherent motion (IVIM) model of diffusion weighted MRI in assessing grades and enhancement patten of uterine cervical cancer. Methods Thirty one patients with pathologically proven cervical cancer, who underwent MRI scan preoperatively, were analyzed retrospectively and were divided into 3 groups according to their pathological grading of cacer, including 6 with G1 cancer, 17 with G2 and 8 with G3. The diameter of each lesion was ≥1 cm. 10 b values (0, 30, 50, 100, 150, 200, 400, 800, 1 000, 1 500 s/mm2) were used in DWI, and DCE-MRI was performed with a time resolution of 9.8 s. Parameters of DWI (ADC, D, f, D*) and semiquantitative parameters of DCE-MRI (Slop, Maxslop, CER, Washout, AUC90) were measured. One-way ANOVA analysis of variance and Pearson correlation were used to analyze normally distributed continuous data. Kruskal-Wallis H test and Spearman correlation were used to analyze abnormally distributed continuous data. Tumor volume and all of the MRI parameters were compared as well as correlated with pathological grading.The perfusion parameters derived from IVIM were correlated with those derived from dynamic enhanced MR imaging. The sensitivity and specificity of f value to to diagnose G3 cervical cancer and the best cutoff were calculated from areas under the ROC curves. Results Tumor volume of G1,G2 and G3 cancers were(33.8±31.1),(19.6±16.9)and(31.2±29.1)cm3(F=1.147, P=0.332), respectively.ADC values of the three groups were(1.03±0.11)×10-3, (1.00±0.10)×10-3 and(0.90±0.05)×10-3mm2/s, respectively(F= 4.619,P=0.018).D values of the three groups were (0.80 ± 0.11) × 10-3, (0.77 ± 0.06) × 10-3and (0.69 ± 0.06) × 10-3mm2/s ,respectively(F=5.272, P=0.011).f values of the three groups were 0.20±0.02, 0.22±0.03 and 0.24± 0.03, respectively (F=3.524, P=0.043).All of the others were of no significant difference (P>0.05).Both ADC and D correlated negatively with tumor grading (r=-0.464 and-0.493, P=0.009 and 0.005, respectively) . f value correlated positively with tumor grading (r=0.436, P=0.014).Areas of ADC, D and f value under ROC curves to diagnose G3 cancers were 0.179, 0.147 and 0.690, respectively. While the cut-off value of f was 0.22, the diagnostic performance for G3 cancer was with a sensitivity of 75.0% (6/8) and a specificity of 60.9% (14/23). The value of f had weak positive correlations with Slop, Maxslop, CER and AUC90 of semiquantitative analysis of DCE-MRI (r=0.319, 0.337, 0.293 and 0.344, respectively, P<0.01). Conclusion IVIM model of multi-b value DWI may provide information in the assessment of differentiation and en hancement pattern of cervical cancer. Key words: Cervical neoplasms; Magnetic resonance imaging; Comparative study