肝脏孤立性坏死结节的CT、MRI表现与病理对照研究

Solitary Necrotic Nodule of the Liver:CT and MRI Manifestation and Correlation with Pathologic Findings

目的:探讨肝脏孤立性坏死结节(SNN)的CT、MRI表现及其分型诊断价值和病理基础。方法:分析经临床和病理证实的肝孤立性坏死结节29例(所有病例均行MR检查,其中15例行CT检查),探讨SNN的CT、MRI表现及其分型诊断价值和病理基础。结果:①单纯凝固性坏死型(14例),T1WI、T2WI上均呈低或低-等信号,增强扫描病灶内凝固性坏死无强化,周围包膜呈延迟强化。其中8例行CT检查,CT平扫呈低或等密度,增强扫描无强化,5例可见包膜呈延迟期环形强化。②伴液化性坏死型(5例),T1WI上呈低信号,较大病灶内可见更低信号;T2WI上病灶呈低-等信号,其内液化性坏死呈点片状更高信号;增强后病灶无强化,周围包膜呈轻-中度强化。CT检查3例,CT平扫呈低或等密度,增强扫描无强化,2例周围包膜呈延迟期环形强化。CT不能反映病灶内液化性坏死。③多结节融合型(10例),T1WI呈低信号,其内可见低-等信号分隔;T2WI病灶以等-稍高信号为主,其内可见等或略高信号分隔,其中6例合并液化性坏死还可见裂隙状高信号。增强扫描病灶无强化,其内分隔及周围包膜呈轻-中度强化。CT检查4例,其中3例为低或等密度融合结节,增强扫描内部分隔及周围包膜呈延迟期强化。CT不能显示内部液化性坏死和病灶全部分隔。结论:CT、MRI能较好反映肝脏孤立性坏死结节的分型及各型的病理特征,MRI在多结节融合型和伴液化坏死型的诊断价值明显优于CT。

Purpose： To analyze the classification, CT and MR manifestation, and the pathological basis of solitary necrotic nodule of the liver（SNN）, in order to evaluate CT and MRI as a diagnostic tool. Meth- ods： Twenty - nine cases with pathologically proved SNN were analyzed and correlated with the classifi- cation and its pathological appearances. All 29 cases were undergone MR scans and 15 cases of them were undergone CT scans. Results： （1） Simple coagulation necrosis type （14 cases）： These lesions showed hypo or iso intensity both on T1 and T2 - weighted images and no enhancement was found after Gd DTPA administration, while the capsule of these lesions demonstrated delayed enhancement. Eight cases of them appeared hypo density or iso density on plain CT and no enhancement was found except the capsule in 5 cases. （2） Coagulative necrosis mixed with liquefaction necrosis type（5 cases）： On T1 - weighted images, these lesions showed hypo intensity in the central area of large lesions. On T2 - weighted images, these lesions had a core which represented liquefaction necrosis with hyper -intensity and a peripheral area with hypo intensity or iso intensity in signal. After Gd - DTPA administration, noenhancement was found except that thin capsules showed moderate enhancement at delayed phases. Three cases of them appeared hypo density or iso density on plain CT and no enhancement was found except the capsule in 2 cases. Compared with MRI, CT couldn＇ t reflect liquefaction necrosis element of the lesions. （3） Multi nodular fusion type（10 cases）： The lesions and septa showed hypo or iso in tensity on T 1 - weighted images and hyper or iso intensity on T2 - weighted images. Six cases of them had a core which represented liquefaction necrosis with hyper intensity on T2 - weighted images. After Gd- DTPA administration, no enhancement was found except capsule and septa showed delayed enhance ment. Four cases of them were low density mass on CT plain scan. No enhancement was found except that the capsule and septa showed delayed enhancement in 3 cases. Compared with MRI, CT couldn＇ t reflect liquefaction necrosis element and all the septa of these lesions. Conclusion： CT and MRI appearances could reflect the classification and pathological features of solitary necrotic nodule of the liver, but MRI has more advantages than CT, especially in coagulative necrosis mixed with liquefaction necrosis type and multi nodular fusion type .