成人急性白血病的骨髓MRI表现与定量分析研究

Bone marrow MRI performance and its quantitative analysis in patients with adult acute leukemia

目的:通过MRI分析成人急性白血病患者的骨髓改变,测定腰椎骨髓与脑脊液在T1加权图像(T1WI)上的信号强度比值(SIR值),探讨MRI对成人急性白血病诊断和疗效评估的价值。方法:回顾性分析42例经骨髓穿刺和组织学证实的成人初发急性白血病患者和32名正常对照者的MRI资料,比较成人急性白血病患者的骨髓浸润及治疗前后MRI变化、SIR值改变,评估内容包括腰椎矢状位及骨盆、股骨近端冠状位MRI检查数据,MRI序列主要为自旋回波(SE)T1WI和短时反转回复序列(STIR)。结果:42例急性白血病患者治疗前腰椎骨髓病灶在T1WI上呈弥漫性低信号或不均匀性低信号;在STIR上呈弥漫性高信号或不均匀性高信号。42例成人初发急性白血病患者中有33例行骨盆、股骨近端冠状位MRI。急性淋巴细胞白血病(ALL)与急性非淋巴细胞白血病(ANLL)患者股骨近端的浸润分布提示,ALL的骨髓侵犯范围较ANLL更广泛(P<0.05)。而腰椎MRI定量分析示,初发急性白血病患者的腰椎骨髓SIR值与正常对照者间差异有统计学意义[1.634±0.336比2.903±0.454(P<0.0001)]。9例白血病患者化疗后复查腰椎MRI,其中4例缓解者较化疗前其腰椎骨髓在T1WI上信号升高,STIR上信号降低,与正常对照组腰椎骨髓SIR值间差异无统计学意义;5例复查显示治疗后未缓解者(1.668±0.402)与正常对照组腰椎骨髓SIR值间差异仍有统计学意义(P<0.0001)。ALL组患者腰椎骨髓T1WISIR值较ANLL组低(1.505±0.240比1.742±0.372),差异有统计学意义(P<0.05)。骨穿结果示,骨髓恶性白血病细胞的数量(B%)与腰椎骨髓SIR值呈线性相关。未发现急性白血病患者化疗前初次MRI表现(MRI股骨浸润程度分级及SIR值定量)与其治疗后缓解情况相关。结论:MRI作为一种无创的检查方法,简单易行,有助于成人急性白血病骨髓浸润的诊断和疗效评估。

Objective To study the bone marrow performance in aduh acute leukemia, assess the signal intensity ratio （SIR） under T1WI of the lumbar spine bone marrow and cerebrospinal fluid, and to evaluate the diagnostic and therapeutic effect assessing value of MRI in adult acute leukemia. Methods The MRI performance data from 42 patients with adult acute leukemia confirmed by bone marrow aspiration histologically and 32 normal control subjects were retrospectively analysed. Bone marrow infiltration, changes of MRI and SIR before and after treatment were studied. The evaluation profile included MRI of sagittal slices in the lumbar spine and coronal slices in the pelvis and the proximal femur, MRI serials were mainly SE（spin echo）-T1WI and STIR （short T1 inversion recovery）. Results The lumbar spine bone marrow of all the 42 patients with adult acute leukemia showed diffuse or inhomogeneous low signal intensity on T1WI and diffuse or inhomogeneous high signal intensity on STIR. Of the 33 patients having MRI coronal slices in the pelvis and the proximal femur performed, the extent of bone marrow invasion was higher in acute lymphocytic leukemia （ALL） than in acute non-lymphocytic leukemia （ANLL）. Quantitative analysis of lumbar spine MRI showed that the SIR value was significantly lower in patients with adult acute leukemia than that in normal controls （1.634±0.336 vs 2.903 ± 0.454） （P〈0.0001）. Nine patients had their lumbar spine MRI re-examined after chemotherapy. Of them, 4 patients with remission, the signal on T1WI increased and the signal on STIR decreased, with the results similar to that of normal control; and other 5 patients without remission （1.668±0.402） remained significantly lower than that of normal control （P〈 0.0001）. The SIR value in ALL patients was significantly lower than that in patients with ANLL （1.505±0.240 vs 1.742±0.372）. There was a linear correlation between bone marrow SIR value and amount of bone marrow leukemia cell （B%）.MRI appearance before therapy cannot predict remission after therapy. Conclusions MRI is an useful non-invasive tool for the diagnosis and assessment of therapeutic efficacy in bone marrow infiltration of adult acute leukemia.