The value of whole tumors volume based T2 histogram analysis for differential diagnosis in pediatric posterior fossa tumors

Abstract

Objective To study the value of whole tumors T2WI gray histogram analysis for differential diagnosis of three commonly presented pediatric posterior fossa tumors. Methods A retrospective analysis was conducted to compare brain MRI examination and pathology diagnosis of 133 cases of posterior fossa tumors in pediatric patients in our hospital. Among them, there were 49 cases of ependymoma(there were 25 males and 24 females), 36 cases of astrocytoma(WHO grade Ⅰ)(there were 19 males and 17 females), 48 cases of medulloblastoma(there were 36 males and 12 females), aged 1 to 14 years old, with an average (7±2) years old. Respectively draw the region of interest (ROI) in the T2 MR transaxial images of three groups on each layer of tumor level by using Mazda software and analyze the whole tumors gray histogram, including mean,variance, kurtosis,skewness, perc.01%, perc.10%,perc.50%,perc.90% and perc.99%.The histogram parameters of the three groups were not normally distributed. The Kruskal-Wallis test was used to compare the three groups. Bonferroni test was used to compare the two groups to find out statistical significance of each parameter. Results Through histogram analysis of 9 parameters, these 9 parameters were statistically significant (all P <0.05),including mean,variance, kurtosis,skewness, perc.01%, perc.10%,perc.50%,perc.90% and perc.99%. The sensitivity of skewness to differentiate ependymoma and the astrocytoma was 69.4%, the specificity was 77.8%, the area under the curve was 0.744, and the best cut-off value was -0.08. The sensitivity of kurtosis to differentiate astrocytoma and the medulloblastoma was 95.8%, the specificity was 97.2% and the area under the curve was 0.972, the cut-off was 1.68. The sensitivity of kurtosis to differentiate ependymoma and the medulloblastoma was 91.7%, the specificity was 89.8% and the area under the curve was 0.932,the cut-off was 1.90.They had a high identification efficiency. Conclusions The T2WI gray histogram analysis based whole tumors is helpful for the dignosis of three types of pediatric posterior fossa tumors. Skewness has a high diagnostic efficiency to differentiate ependymoma and the astrocytoma. Kurtosis has a high diagnostic efficiency to differentiate ependymoma and the medulloblastoma. Kurtosis has a high diagnostic efficiency to differentiate ependymoma and medulloblastoma. Key words: Magnetic resonance imaging; Child; Cranial fossa, posterior; Diagnosis, differential