原发性骶尾部脊索瘤的CT分型及征象

目的对治疗前原发性骶尾部脊索瘤(PSC)CT图像分型,并分析其CT征象,为诊断和个性化治疗提供依据。方法回顾性分析101例PSC患者治疗前的CT图像,包括肿瘤的部位、范围、大小、密度、肿瘤与邻近结构的关系。按照肿瘤的部位由上及下分为Ⅰ~Ⅳ型,并根据肿瘤侵犯的范围从小到大分为a^d亚型。采用Kruskal-Wallis H检验比较PSC各亚型的占比,并对各亚型之间进行两两比较。采用R×C列联表精确概率检验比较分型和亚型肿瘤钙化的发生率。采用单因素方差分析及LSD-t检验对各分型和亚型肿瘤的大小和密度进行分析、比较。结果101例PSC中,Ⅰ~Ⅳ型的发生率分别为17.8%、30.7%、36.6%、14.9%,a^d亚型的占比分别为9.9%、25.7%、58.4%、5.9%。各亚型的占比差异具有统计学意义(P=0.012)。c亚型明显高于a亚型(P=0.039),d亚型明显低于a亚型(P=0.036),其余各型之间无明显差异。各分型肿瘤内钙化的差异无统计学意义(P=0.233);各亚型肿瘤内钙化的差异有统计学意义(P=0.003),a^d亚型肿瘤钙化的比率逐渐增加。Ⅰ型肿瘤的左右径及上下径明显大于Ⅱ~Ⅳ型(P<0.05)。a亚型与b亚型肿瘤之间前后径的差异无统计学意义(P=0.102),b^d亚型之间前后径的差异均有统计学意义(P<0.05);不同亚型肿瘤之间的左右径、上下径之间的差异均有统计学意义(P<0.05),a亚型径线最小,d亚型径线最大。结论101例PSC中,Ⅱ、Ⅲ型最多见,肿瘤较少累及第一骶骨;各亚型中,a型较少见,c亚型最多见,d亚型最少见。肿瘤的密度与分型无关,肿瘤内钙化与亚型有关。Ⅰ型肿瘤侵犯的范围较Ⅱ~Ⅳ型广泛,a^d亚型肿瘤的径线逐渐增大,CT分型有利于判断肿瘤的范围。PSC诊断延迟现象比较明显,但很少发生远处侵犯和转移。CT图像可对治疗前PSC分型,为诊断和个性化治疗提供依据。

The Classification and Features of Primary Sacrococcygeal Chordoma Based on CT Imaging

Objective To develop a CT imaging classification system and analyze CT imaging features for pretreatment primary sacrococcygeal chordoma(PSC),provide evidences for its diagnosis and individualized treatment.Methods Pretreatment CT imaging of 101 patients with a histopathological diagnosis of PSC were analyzed retrospectively,including tumor location,extent,size,intensity,involvement of adjacent structure.According to the location of the tumor,it is divided into typeⅠ~Ⅳfrom top to bottom,and according to the range of tumor invasion,it is divided into subtypes a^d.The Kruskal-Wallis H test was used to compare the proportion of PSC subtypes,and the pairwise comparisons were performed among the subtypes.The R×C contingency table exact probability test was used to compare the incidence of calcification in the subtype and subtype tumors.One-way analysis of variance and LSD-t test were used to analyze and compare the size and density of tumors of different types and subtypes.Results In 101 cases,the ratios of typeⅠ-Ⅳwere 17.8%,30.7%,36.6%and 14.9%respectively;the ratios of subtype a-d were 9.9%,25.7%,58.4%and 5.9%respectively.Differences of ratio among subtypes had statistical significance(P=0.012).The proportion of subtype c was higher than subtype a(P=0.039),while the proportion of subtype d was lower than subtype a(P=0.036).There were no significant differences among the other subtypes.For the occurrence rates of tumor calcification,there were no significant differences among different types(P=0.233),but not among subtypes(P=0.003).The occurrence rates of tumor calcification were increasing from subtype a to d.The transverse dimensions and vertical dimensions of typeⅠwere larger than typeⅡtoⅣ(P<0.05).For the anteroposterior dimensions,there were significant differences from subtype b to d(P<0.05),but not between subtype a and b(P=0.102).The transverse and vertical dimensions had significant different among different subtypes(P<0.05);the dimensions were increasing from subtype a to subtype d.Conclusion TypeⅡandⅢwere common in pretreatment CT imaging of 101 PSC;the first sacral vertebra was seldom involved;subtype a was uncommon,subtype c was the commonest and subtype d was rare.The intensity of tumor was not associated with CT type and the occurrence rates of tumor calcification was related to subtype.The extent of tumor in typeⅠwas wider than the other types;the tumor dimensions were increasing from subtype a to d;CT imaging classification system was beneficial to determine the extent of tumor.PSC diagnosis is delayed,but distant invasion and metastasis rarely occur.CT images can be used to classify PSC before treatment,providing a basis for diagnosis and personalized treatment.