【Abstract】
Objectives: To determine whether water kurtosis and diffusional metrics derived from diffusional kurtosis imaging (DKI) within primary central nervous system lymphomas (PCNSLs) and high-grade gliomas (HGGs) correlate with cellularity or/and nuclear-to-cytoplasmic (N/C) ratio.
Methods: Forty-four and 43 pathologically confirmed high-grade glioma and primary central nervous system lymphoma specimens between May 2013 and November 2016 were retrospectively reviewed. Diffusional metrics; kurtosis metrics; cellularity; and N/C ratios in PCNSLs and HGGs were compared using the Mann–Whitney U test (significant level, P＜0.007 [0.05/7]); Bonferroni correction).
Results: Mean kurtosis (MK), axial kurtosis (K//), and radial kurtosis (K⊥) in PCNSLs were 0.857 (0.693–0.924), 0.837 (0.660–0.941), and 0.834 (0.685–0.937), respectively; and 0.629 (0.524–0.716), 0.575 (0.511–0.689), and 0.675 (0.532–0.766), respectively, in HGGs (all P＜0.001). No significant differences in fractional anisotropy (FA), mean diffusion (MD), axial diffusion (λ//), and radial diffusion (λ⊥) were found between HGGs and PCNSLs. Cellularity was higher in PCNSLs than in HGGs (P=0.125); whereas, the N/C ratio in PCNSLs was significantly higher than in HGGs (P＜0.001). All DKI metrics (FA, MD, λ//, λ⊥, MK, K//, and K⊥) were significantly correlated with N/C ratio in PCNSLs with correlation coefficients being Rho=0.418, -0.722, -0.525, -0.768, 0.704, 0.579, and 0.686, respectively. Cellularity in PCNSLs and HGGs did not correlate with any kurtosis or diffusional metrics.
Conclusions: Difference of kurtosis parameters between PCNSLs and HGGs is correlated with their diverse N/C ratio.
【中文摘要】
目的：探索擴散峰度成像（diffusion kurtosis imaging, DKI）能否鑑別高級別膠質瘤和中樞神經系統淋巴瘤，DKI的峰度參數及擴散參數是否與它們不同的細胞密度、核漿比有關。
方法：收集81例患者影像學診斷為高級別膠質瘤（high-grade gliomas，HGGs）或中樞神經系統淋巴瘤(primary central nervous system lymphomas, PCNSLs)的患者，術前均進行MRI掃描，掃描序列包括 FSE-T1WI、FSE-T2WI、T2-FLAIR、DKI、增強3D-BRAVO序列。術後所有患者均進行了點對點穿刺獲取組織標本，對所有患者標本進行HE染色確定組織病理類型和計算細胞密度。HE組織病理染色證實為淋巴瘤的，對其標本行CD20免疫組織化學染色，用於測量其核漿比。HE組織病理證實為膠質瘤的進一步行抗GFAP免疫組織化學染色，用於其核漿比的定量。用經Bonferroni 校正的Mann-Whitney U Test比較中樞神經系統淋巴瘤、高級別膠質瘤DKI成像的峰度參數、擴散參數、定量的細胞密度、核漿比，並進行影像與病理的Spearman秩相關分析。統計學顯著水平定為P<0.05取雙尾。
結果：PCNSL的平均峰度（mean kurtosis， MK）、軸向峰度（axial kurtosis，K//）、徑向峰度（radial kurtosis，K⊥）分別為0.857（0.693-0.924）、0.837(0.660-0.941)、 0.834（0.685-0.937），HGG的平均峰度（mean kurtosis， MK）、軸向峰度（axial kurtosis，K//）、徑向峰度（radial kurtosis，K⊥）分別為0.629（0.524-0.716）、0.575（0.511-0.689）、0.675（0.532-0.766）；所有峰度參數在二者間均存在顯著差異，P值均小於0.001。而擴散參數各向異性分數（fractional anisotropy, FA）、平均擴散（mean diffusion, MD）、軸向擴散（axial diffusion，λ//）、徑向擴散（radial diffusion，λ⊥）在HGGs和PCNSLs間無顯著差別。PCNSLs的細胞密度高於HGGs，但未達統計學顯著水平（P=0.125）；然而，PCNSLs的核漿比顯著大於HGGs，P<0.001。所有DKI所得到的擴散參數及峰度參數（FA、MD、λ//、λ⊥、MK、K//、K⊥）均與PCNSLs的核漿比顯著相關，相關係數Rho值分別為0.418、-0.722、-0.525、-0.768、-0.704、0.579和0.686。PCNSLs和HGGs兩種腫瘤的細胞密度與DKI的峰度及擴散參數均無相關性。
結論：DKI成像能鑑別PCNSLs和HGGs與二者不同的核漿比有關。