急性白血病椎体骨髓浸润的扩散加权成像研究

Vertebral bone marrow infiltration of acute leukemia： diffusion-weighted imaging study

目的探讨椎体骨髓单方向扩散屏气DWI方法，分析急性白血病（AL）患者椎体骨髓浸润DWI的临床应用价值。方法对42例确诊AL患者和15名健康志愿者行胸腰椎矢状面单次激发回波平面DWI（SS—EPI—DWI）序列扫描（b值为0、650s／mm^2），扩散方向为头-足（S／I）、前-后（A／P）和左-右（R／L）方向，每个方向DWI采集时间均为12S，闭气采集。分别在3个方向的ADC图上测量多个椎体骨髓的ADC值，比较3个扩散方向的ADC值的差别。AL患者分为初发未治疗组13例和治疗组29例[初发治疗未缓解（NR）组7例。初发治疗完全缓解（CR）组8例、治疗巩固组14例]。比较不同治疗阶段AL患者ADC值的差异用方差分析、t检验，ADC值与骨髓原始细胞比例的相关性采用Pearson分析。结果57例受试者362个椎体S／I、A／P和R／L方向的ADC值分别为（0．758±0．009）、（0．732±0．009）、（0．758±0．009）×10^-3mm^2／s，三者之间ADC值的差异无统计学意义（F=2．958，P〉0．05）。15名健康志愿者94个椎体ADC值为（0．697±0．122）×10^-3mm^2／s，13例初发未治疗组85个椎体ADC值为（0．592±0．071）×10^-3mm^2／s，两者差异具有统计学意义（t=2．568，P〈0．05）；29例治疗组AL患者183个椎体ADC值为（0．796±0．225）×10^-3mm^2／s，与初发未治疗组比较，差异有统计学意义（t=1．332，P〈0．05）；初发治疗CR组＋巩固治疗组共140个椎体ADC值为（0．786±0．184）×10^-3mm^2／s，初发治疗NR组43个椎体ADC值为（0．804±0．327）×10^-3mm^2／s，两者差异无统计学意义（t=-0．160，P〉0．05）。初发未治疗组的S／IADC值与骨髓象原始细胞比例（中位数26．4％，范围7．9％～48．2％）呈线性负相关（r=-0．524，P〈0．05）。结论椎体骨髓DWI为各向同性，单方向屏气DWI能提高图像质量。初发AL患者ADC值降低，化疗后ADC值增加，初发组ADC值与骨髓象原始细胞比例呈线性负相关。

Objective Using single direction dispersion breathless DWI, to analyze the value of DWI for vertebral bone marrow infiltration in patients with acute leukemia （AL）. Methods Forty-two patients with AL and 15 healthy volunteers received vertebral sagittal DWI with single shot spin-echo echoplan imaging （SS-SE-EPI） sequence（b value = 0,650 s/mm^2） at a GE Signa Excite 1.5 T scanner with 8 channels body coil. DWI for all patients were performed from three directions, including from superior to inferior （S/I）, from anterior to posterior （A/P） and from right to left （R/L）. The apparent diffusion coefficient （ADC） value was measured on ADC map from each direction using GE-Function tool DWI software. Forty two patients consisted of 13 onset with untreated patients and 29 treated patients （7 nonremission,8 complete remission and 14 consolidation therapy）. The ADC values among the three diffusion directions were compared. Analysis of variance and t test were used to compare the ADC values in different AL stages, Pearson correlation analysis was used to analyze the correlation between ADC values and the percentage of bone marrow progenitor ceils. Results The ADC values from S/I, A/P and R/L of 362 vertebras in the 57 subjects are （0. 758 ±0. 009） ×10^-3mm^2/s, （0. 732 ±0. 009） ×10^-3mm^2/s and （0. 758 ± 0. 009） ×10^-3mm^2/s, respectively. There is no statistical significance （ F = 2. 958, P 〉 0. 05 ）. The ADC values from S/I of 94 vertebras in 15 healthy volunteers is （0. 697± 0. 122） ×10^-3mm^2/s, of 85 vertebras in 13 untreated AL patients is （0. 592 ±0. 071）×10^-3mm^2/s. There is statistical significance between them（t = 2. 568,P 〈 0. 05） ;The ADC value of 183 vertebras in 29 treated AL patients [ （0. 796 ± 0. 225） ×10^-3mm^2/s ] is higher than that in untreated patients with statistical significance （t = - 1. 552, P 〈 0. 05）. One hundred and forty vertebras in patients with complete remission and consolidation therapy were [ （0. 786±0. 184） ×10^-3mm^2/s] ,and 43 vertebras in patients with non-remission（NR） [ （0. 804 ± 0. 327 ） ×10^-3mm^2/s ], there was not statistical significance between them（ t = - 0. 160, P 〉 0.05 ）. The ADC values from S/I direction of untreated patients showed significant negative correlation with the proportion of the blast cell in the bone marrow （ median value 26. 4%. Min 7.9% , Max 48.2% ） （ r = - 0. 524, P 〈 0. 05 ）. Conclusions DWI of vertebral bone marrow is isotropy. ADC value is a non-invasive and quantitative index for evaluating the pathogenetic condition of AL.