Gd-EOB-DTPA增強(qiáng)MRI在肝臟局灶性病變中的應(yīng)用進(jìn)展

張薇薇， 劉曦嬌， 李崢艷， 黃子星， 宋彬

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·普美顯增強(qiáng)MRI專題·

Gd-EOB-DTPA增強(qiáng)MRI在肝臟局灶性病變中的應(yīng)用進(jìn)展

張薇薇， 劉曦嬌， 李崢艷， 黃子星， 宋彬

肝臟局灶性病變是常見的肝臟疾病，常用的影像學(xué)檢查方法包括超聲、CT及MRI，MRI因?yàn)榫哂辛己玫慕M織對(duì)比及可使用多種對(duì)比劑等優(yōu)勢(shì)，成為診斷肝臟局灶性病變的重要檢查方法。Gd-EOB-DTPA是通過(guò)肝細(xì)胞特異性攝取的對(duì)比劑，Gd-EOB-DTPA增強(qiáng)MRI對(duì)于肝臟局灶性病灶的診斷、鑒別診斷、指導(dǎo)治療等具有重要意義。本文就Gd-EOB-DTPA增強(qiáng)MRI在肝臟局灶性病變中的應(yīng)用做一綜述。

磁共振成像； Gd-EOB-DTPA； 肝臟病變

肝臟局灶性病變是常見的肝臟疾病，包括原發(fā)性局灶性結(jié)節(jié)增生(focal nodule hyperplasia,FNH)、肝腺瘤(hepatocellular adenoma,HCA)、肝癌、轉(zhuǎn)移瘤等。早期發(fā)現(xiàn)病灶、定性診斷、指導(dǎo)臨床治療、判斷預(yù)后等對(duì)臨床非常重要。近年來(lái)，隨著影像技術(shù)的飛速發(fā)展，肝臟局灶性病灶的檢出率明顯提高，影像學(xué)檢查在肝臟局灶性病變的診斷與鑒別診斷中發(fā)揮著重要作用[1,2]，包括超聲、CT及MRI。MRI具有軟組織分辨力高，可多參數(shù)、多方位、多序列成像、無(wú)電離輻射等優(yōu)點(diǎn)[3]，在肝臟疾病診斷方面具有重要作用。

目前臨床上應(yīng)用的MRI對(duì)比劑大致分為五類：①分布于細(xì)胞外的對(duì)比劑；②肝膽特異性對(duì)比劑(hepatobiliary-specific contrast agent，HSCA)，是通過(guò)肝細(xì)胞選擇性攝取的對(duì)比劑，能被肝細(xì)胞吸收并通過(guò)膽道系統(tǒng)排泄，因而適用于肝臟病變的檢出；③分布于網(wǎng)狀內(nèi)皮系統(tǒng)或巨噬細(xì)胞-單核細(xì)胞吞噬系統(tǒng)的對(duì)比劑，即超順磁性氧化鐵(superparamagnetic iron oxide,SPIO)顆粒，它適用于具有網(wǎng)狀內(nèi)皮系統(tǒng)的器官和組織的顯示；④血管內(nèi)或血池性對(duì)比劑，如超微粒超順磁性氧化鐵(USPIO)顆粒，其顆粒直徑小，可逃避網(wǎng)狀內(nèi)皮系統(tǒng)的吞噬，且其血液半衰期延長(zhǎng)，表現(xiàn)為短T1、短T2效應(yīng)，適用于帶有特定分子的細(xì)胞組織顯示，可作為MRI分子影像研究的示蹤劑；⑤其它對(duì)比劑[4]。

Gd-EOB-DTPA簡(jiǎn)介

Gd-EOB-DTPA，又名釓塞酸二鈉(商品名普美顯)，屬于肝膽特異性對(duì)比劑，經(jīng)靜脈注射后到達(dá)肝臟，快速滲透過(guò)肝內(nèi)毛細(xì)血管網(wǎng)而分布于細(xì)胞外間隙內(nèi)并迅速達(dá)到平衡狀態(tài)，并經(jīng)腎臟排泄。

Gd-EOB-DTPA分子中Gd通過(guò)增加T1弛豫率縮短組織T1弛豫時(shí)間，可用作非特異性的細(xì)胞外對(duì)比劑，具有與其他對(duì)比劑效一致的動(dòng)態(tài)增強(qiáng)效果[4]，從而有效顯示病灶的血供情況；另一方面，其親脂性的EOB基團(tuán)使Gd-EOB-DTPA具有與血漿蛋白結(jié)合的能力，能被肝細(xì)胞膜上的有機(jī)陰離子轉(zhuǎn)運(yùn)系統(tǒng)選擇性攝取并經(jīng)過(guò)膽道系統(tǒng)排泄。正常肝腎功能人體內(nèi)約50%由肝細(xì)胞攝取并經(jīng)膽道排泄，50%經(jīng)腎臟代謝[5]。因此在肝膽期成像中，具有正常功能肝細(xì)胞的實(shí)質(zhì)因攝取對(duì)比劑而強(qiáng)化；肝細(xì)胞功能減退、正常肝細(xì)胞數(shù)量減少或缺失時(shí)，該病變部位因攝取較少或不攝取對(duì)比劑而表現(xiàn)為稍低或低信號(hào)，從而為病變的檢出和鑒別診斷提供信息[6]。

Gd-EOB-DTPA增強(qiáng)MRI檢查既能反映腫瘤血供情況，也能反映肝細(xì)胞功能，從而提高肝臟局灶性病變的檢出和診斷能力[7,8]。既往研究顯示，與超聲、CT、傳統(tǒng)動(dòng)態(tài)增強(qiáng)MRI以及SPIO增強(qiáng)MRI等成像技術(shù)相比，Gd-EOB-DTPA增強(qiáng)MRI檢查在診斷和鑒別診斷肝臟局灶性病變方面具有一定優(yōu)勢(shì)[9,10]。

和Gd-DTPA及其它傳統(tǒng)細(xì)胞外對(duì)比劑相比，Gd-EOB-DTPA的T1弛豫效應(yīng)更強(qiáng)。相比于Gd-DTPA 0.1 mmol/kg的劑量，Gd-EOB-DTPA僅需要0.025 mmol/kg(0.1 mL/kg)的劑量即可達(dá)到臨床診斷需要[11]。Gd-EOB-DTPA經(jīng)靜脈注射流率為1～2 mL/s，對(duì)比劑注射后需用生理鹽水20 mL以相同注射流率沖洗，以優(yōu)化動(dòng)脈期掃描[12,13]。Gd-EOB-DTPA增強(qiáng)MRI檢查掃描序列包括同、反相位的T1WI、自旋回波序列(SE)T2WI、注射對(duì)比劑后應(yīng)用3D梯度回波序列T1WI或容積式內(nèi)插值法屏氣檢查(volumetric interpolated breath-hold examination，VIBE)序列軸面T1WI。推薦的肝膽期采集時(shí)間為注射對(duì)比劑后10～20 min，有學(xué)者提出對(duì)于肝硬化或血清膽紅素水平升高者，延遲20 min以上更合適。

Gd-EOB-DTPA的不良反應(yīng)不常見，且絕大多數(shù)為輕度到中度，包括頭痛、頭暈、發(fā)熱、面部潮紅、注射部位反應(yīng)(包括對(duì)比劑滲漏，注射部位冷感、疼痛等)等。對(duì)于嚴(yán)重的急慢性腎損傷患者，注射Gd-EOB-DTPA可能會(huì)發(fā)生腎源性系統(tǒng)纖維化；但由于Gd-EOB-DTPA注射劑量低，且具有雙通道排泄機(jī)制，理論上其發(fā)生腎源性系統(tǒng)纖維化的概率較其它釓對(duì)比劑低，目前尚無(wú)相關(guān)報(bào)道。Gd-EOB-DTPA禁用于孕婦及哺乳期婦女。

診斷與鑒別診斷

1.原發(fā)性肝癌

原發(fā)性肝癌是臨床上最常見的惡性腫瘤之一，其發(fā)病率逐年增長(zhǎng)，居于惡性腫瘤的第5位，年死亡人數(shù)接近60萬(wàn)[14,15]。肝細(xì)胞癌 (hepatocelluar carcinoma，HCC)是原發(fā)性肝癌中最主要的類型。HCC的發(fā)生與肝硬變基礎(chǔ)上產(chǎn)生的肝細(xì)胞結(jié)節(jié)密切相關(guān)，發(fā)現(xiàn)這些結(jié)節(jié)并準(zhǔn)確診斷和鑒別診斷，對(duì)HCC的診斷、治療、監(jiān)測(cè)和預(yù)后均具有重要價(jià)值[16,17]。

HCC在MRI圖像上多表現(xiàn)為T2WI高信號(hào)，增強(qiáng)掃描往往具有典型的“快進(jìn)快出”征象，即動(dòng)脈期強(qiáng)化，門靜脈期或平衡期強(qiáng)化減弱。由于大部分HCC病灶對(duì)Gd-EOB-DTPA攝取減少，在肝膽期多表現(xiàn)為低信號(hào)。眾多文獻(xiàn)報(bào)道，Gd-EOB-DTPA增強(qiáng)MRI肝膽期對(duì)HCC尤其是小肝癌(直徑<2.0 cm)的診斷具有重要價(jià)值，特別是結(jié)合擴(kuò)散灌注成像掃描時(shí)，在診斷和鑒別診斷肝硬化相關(guān)結(jié)節(jié)及小肝癌病灶上優(yōu)于其他檢查技術(shù)，應(yīng)作為首選檢查方法[18-21]。Sugimoto等[22，23]研究認(rèn)為Gd-EOB-DTPA增強(qiáng)MRI和增強(qiáng)超聲對(duì)乏血供HCC具有相似的診斷效能，但增強(qiáng)超聲對(duì)富血供病灶的診斷準(zhǔn)確度更高。與MSCT相比，Gd-EOB-DTPA增強(qiáng)MRI對(duì)HCC，尤其是小肝癌的診斷敏感度和準(zhǔn)確度優(yōu)于CT[22，24，25]。數(shù)項(xiàng)研究比較Gd-EOB-DTPA和Gd-DTPA增強(qiáng)MRI對(duì)小肝癌的診斷效能[26，27]，認(rèn)為前者更敏感。Kim等[28]報(bào)道Gd-EOB-DTPA增強(qiáng)MRI對(duì)直徑<3.0 cm HCC的診斷敏感度明顯高于SPIO增強(qiáng)MRI。Park等[29]研究比較Gd-EOB-DTPA與Gd-BOPTA增強(qiáng)MRI對(duì)HCC的診斷效能，結(jié)果顯示前者發(fā)現(xiàn)了59例病灶中的51例，而后者僅發(fā)現(xiàn)了38例。

2.肝臟轉(zhuǎn)移瘤

肝臟是轉(zhuǎn)移性腫瘤好發(fā)部位之一，約占所有實(shí)質(zhì)性器官轉(zhuǎn)移瘤的25%[30]。結(jié)直腸癌、食管癌、胃癌、胰腺癌、乳腺癌、肺癌等均易發(fā)生肝臟轉(zhuǎn)移。轉(zhuǎn)移性肝癌可單發(fā)或多發(fā)，屬于腫瘤晚期，預(yù)后差，及時(shí)發(fā)現(xiàn)肝轉(zhuǎn)移瘤，明確其數(shù)目和位置，對(duì)于原發(fā)病灶的尋找、治療方式的選擇及預(yù)后都有重要意義[31]。

在增強(qiáng)MRI圖像上，肝臟轉(zhuǎn)移瘤多表現(xiàn)為環(huán)形強(qiáng)化或邊緣強(qiáng)化。由于不含肝細(xì)胞，轉(zhuǎn)移瘤在肝膽期表現(xiàn)為低信號(hào)，這與周圍強(qiáng)化的肝實(shí)質(zhì)形成對(duì)比，從而提高檢出率。有時(shí)轉(zhuǎn)移瘤在肝膽期表現(xiàn)為周邊強(qiáng)化，這可能是由于腫瘤增大后壓迫鄰近正常肝實(shí)質(zhì)，其仍具有正常肝功能，能夠攝取Gd-EOB-DTPA，但排泄延遲所致[32]。有文獻(xiàn)指出，常規(guī)平掃M(jìn)RI序列已能發(fā)現(xiàn)絕大多數(shù)肝臟轉(zhuǎn)移瘤，Gd-EOB-DTPA增強(qiáng)MRI肝膽期成像還能有助于某些疾病如肝臟嗜酸性粒細(xì)胞浸潤(rùn)等與肝轉(zhuǎn)移瘤的鑒別[33]。與擴(kuò)散加權(quán)成像相比，Gd-EOB-DTPA增強(qiáng)MRI對(duì)肝臟轉(zhuǎn)移瘤的檢出率更高，不過(guò)擴(kuò)散加權(quán)成像對(duì)微小轉(zhuǎn)移灶的檢出率更高[34，35]。Niekel等[36,37]比較CT、MRI、PET及PET/CT對(duì)結(jié)腸癌肝轉(zhuǎn)移瘤的診斷能力，提出MRI是結(jié)腸癌肝轉(zhuǎn)移瘤的首選檢查方法，亞組分析結(jié)果顯示Gd-EOB-DTPA增強(qiáng)MRI的診斷敏感度為94%。

3.膽管細(xì)胞癌

膽管細(xì)胞癌組織學(xué)包含膽管細(xì)胞和纖維成分，不含肝細(xì)胞，Gd-EOB-DTPA增強(qiáng)MRI顯示其動(dòng)態(tài)期強(qiáng)化表現(xiàn)與常規(guī)MRI類似，動(dòng)脈期、門脈期及平衡期表現(xiàn)為進(jìn)行性強(qiáng)化；肝膽期由于周圍肝實(shí)質(zhì)強(qiáng)化明顯，表現(xiàn)為相對(duì)低信號(hào)。膽管細(xì)胞癌影像學(xué)上與肝細(xì)胞癌鑒別有時(shí)較困難，細(xì)胞學(xué)檢查或組織病理學(xué)檢查是鑒別兩者的金標(biāo)準(zhǔn)[38]。

4.肝血管瘤

肝血管瘤是肝臟最常見的良性腫瘤，以海綿狀血管瘤多見，其組織學(xué)改變?yōu)榛螖U(kuò)張的血竇，不含正常肝細(xì)胞。典型血管瘤的診斷并不困難，MRI常規(guī)序列即可對(duì)其進(jìn)行較準(zhǔn)確地定位、定性診斷，典型征象包括T2WI高信號(hào)，動(dòng)脈期邊緣結(jié)節(jié)樣強(qiáng)化，隨時(shí)間推移強(qiáng)化進(jìn)一步向中心推進(jìn)，呈“快進(jìn)慢出”表現(xiàn)；在Gd-EOB-DTPA增強(qiáng)MRI肝膽期表現(xiàn)為低信號(hào)。

文獻(xiàn)報(bào)道普遍認(rèn)為肝血管瘤Gd-EOB-DTPA肝膽期圖像并不能為診斷提供更多有價(jià)值的信息，且肝膽期的某些征象可能增加診斷難度[39]。小的血管瘤可能在動(dòng)脈期表現(xiàn)為快速均一強(qiáng)化，而在肝膽期表現(xiàn)為低信號(hào)，表現(xiàn)為“假廓清征”，與富血供腫瘤較難鑒別[40]。Tamada等[41]發(fā)現(xiàn)約47%的肝血管瘤在Gd-EOB-DTPA增強(qiáng)MRI肝膽期表現(xiàn)為病變周圍低信號(hào)，這與轉(zhuǎn)移瘤等惡性病灶的肝膽期表現(xiàn)難以鑒別，因此出現(xiàn)這一征象的病灶還需結(jié)合其他掃描序列圖像和臨床表現(xiàn)進(jìn)行綜合診斷?？紤]到存在上述問(wèn)題，目前對(duì)于懷疑肝血管瘤的患者并不推薦行Gd-EOB-DTPA增強(qiáng)MRI檢查[42]。

5.FNH

FNH是肝內(nèi)常見的良性腫瘤，多好發(fā)于女性。FNH是肝細(xì)胞對(duì)先天性血管發(fā)育異常的一種增生性反應(yīng)，由正常肝細(xì)胞異常排列形成，內(nèi)可見小膽管，但不與大膽管相通。FNH最大的病理特點(diǎn)是以星狀纖維瘢痕組織為核心向周圍呈輻射狀分布的纖維分隔，星狀瘢痕組織內(nèi)通常含一條或多條動(dòng)脈。

FNH在T1WI、T2WI圖像上多與正常肝實(shí)質(zhì)信號(hào)相近，增強(qiáng)掃描呈明顯強(qiáng)化，伴中心瘢痕延遲強(qiáng)化[43,44]。Grazioli等[45]研究顯示，68%的FNH在肝膽期表現(xiàn)為高信號(hào)，28.9%表現(xiàn)為等信號(hào)。Zech等[44]分析59例FNH在注射對(duì)比劑后20 min時(shí)采集的肝膽期圖像，發(fā)現(xiàn)大多數(shù)FNH表現(xiàn)為相對(duì)于正常肝實(shí)質(zhì)的高信號(hào)、等信號(hào)或混雜信號(hào)；之所以部分FNH在肝膽期表現(xiàn)為等信號(hào)，一種可能的解釋是病灶內(nèi)含有正常肝細(xì)胞和膽管；表現(xiàn)為高信號(hào)是因?yàn)楦渭?xì)胞內(nèi)小膽管并未與大膽管連通，導(dǎo)致對(duì)比劑殘留；也有少數(shù)病灶在肝膽期表現(xiàn)為相對(duì)低信號(hào)，其機(jī)制目前尚不清楚。

6.HCA

HCA是罕見的肝臟良性腫瘤，組織學(xué)上HCA細(xì)胞內(nèi)有大量糖原和脂質(zhì)沉積，但缺乏膽管結(jié)構(gòu)。

在MRI圖像上，HCA多表現(xiàn)為T1WI等信號(hào)或稍高信號(hào)，動(dòng)脈期呈均勻或不均勻明顯強(qiáng)化，門脈期和平衡期呈等信號(hào)。Grazioli等[45]發(fā)現(xiàn)32例HCA在肝膽期均表現(xiàn)為相對(duì)正常肝實(shí)質(zhì)的低信號(hào)。另一篇文獻(xiàn)發(fā)現(xiàn)3例HCA在Gd-EOB-DTPA增強(qiáng)MRI肝膽期表現(xiàn)為低信號(hào)[46]。Sakamoto等[47]報(bào)道了1例糖原貯積癥男性患者多發(fā)HCA，肝膽期表現(xiàn)為高、低混雜信號(hào)。

HCA和FNH均為富血供病變，常規(guī)影像學(xué)檢查對(duì)其鑒別診斷存在一定困難，有學(xué)者嘗試用Gd-EOB-DTPA增強(qiáng)MRI肝膽期成像鑒別兩者，結(jié)果顯示，肝腺瘤在肝膽期多表現(xiàn)為低信號(hào)，而FNH多表現(xiàn)為等信號(hào)或高信號(hào)，因此肝膽期圖像能為兩者的鑒別診斷提供相關(guān)依據(jù)[48-50]。

評(píng)價(jià)腫瘤分化程度

評(píng)價(jià)HCC的惡性程度、病理分級(jí)對(duì)臨床制定治療方案及評(píng)價(jià)預(yù)后至關(guān)重要?，F(xiàn)有的HCC腫瘤分化程度評(píng)估手段存在局限性，如病理組織學(xué)或細(xì)胞學(xué)檢查是目前已知的金標(biāo)準(zhǔn)，但其為有創(chuàng)性檢查，難以廣泛應(yīng)用。因此，需要尋找新的評(píng)估HCC腫瘤分化程度的檢查方法。

有研究認(rèn)為肝膽期HCC的強(qiáng)化程度與其分化程度相關(guān)，Lee等[51]報(bào)道了4例肝膽期表現(xiàn)為高信號(hào)的HCC，其病理分級(jí)均為高分化腫瘤。Kogita等[52]計(jì)算不同分化程度的HCC在肝膽期的強(qiáng)化率與分化程度的關(guān)系，認(rèn)為病灶強(qiáng)化程度低者分化程度更差，但該強(qiáng)化率在HCC和退變結(jié)節(jié)間差異無(wú)統(tǒng)計(jì)學(xué)意義。Kim等[53]研究認(rèn)為Gd-EOB-DTPA增強(qiáng)MRI能預(yù)測(cè)肝功能CTP分級(jí)A級(jí)患者的肝癌分化程度。Frericks等[54]通過(guò)對(duì)比分析有肝硬化基礎(chǔ)的HCC患者Gd-EOB-DTPA增強(qiáng)MRI圖像和術(shù)后病理結(jié)果，發(fā)現(xiàn)HCC在動(dòng)脈期和肝膽期的強(qiáng)化程度與病理分級(jí)不存在相關(guān)性。Kobayashi等[55]提出僅考慮病灶在肝膽期的強(qiáng)化程度，相對(duì)于正常肝實(shí)質(zhì)呈等信號(hào)或高信號(hào)的病灶進(jìn)展為HCC的概率與低信號(hào)病灶間差異無(wú)統(tǒng)計(jì)學(xué)意義。因此，HCC肝膽期表現(xiàn)與腫瘤病理學(xué)惡性程度及預(yù)后之間的關(guān)系尚不明確。

HCC微血管生成及微血管侵犯

腫瘤是典型的血管依賴性病變，血管生成不僅能促進(jìn)腫瘤的生長(zhǎng)，還與腫瘤浸潤(rùn)、轉(zhuǎn)移及復(fù)發(fā)密切相關(guān)。HCC是富血供腫瘤，血管生成在HCC的生長(zhǎng)與轉(zhuǎn)移過(guò)程中起著重要作用，其中微血管密度(microvessel density，MVD)是評(píng)價(jià)腫瘤新生血管的有效指標(biāo)，但其表達(dá)需通過(guò)免疫組化顯示，限制了其在臨床中的應(yīng)用。目前，隨著MRI技術(shù)的飛速發(fā)展，使影像學(xué)無(wú)創(chuàng)評(píng)價(jià)腫瘤血管生成成為可能。Frouge等分析了Gd -DTPA 動(dòng)態(tài)增強(qiáng)MRI與乳腺腫瘤MVD的關(guān)系。Buadu等[56]將73例乳腺病變的MRI時(shí)間-強(qiáng)度曲線分成四型，發(fā)現(xiàn)曲線的類型和最大對(duì)比增強(qiáng)率與組織學(xué)MVD的高低有關(guān)。也有研究提示HCC動(dòng)態(tài)增強(qiáng)MRI與腫瘤MVD相關(guān)，HCC的MR對(duì)比增強(qiáng)率與MVD值呈正相關(guān)，快速上升型曲線腫瘤的MVD值高，緩慢上升型曲線腫瘤的MVD值低[57-59]。但目前還沒(méi)有Gd-EOB-DTPA增強(qiáng)MRI與MVD的相關(guān)研究，尚需進(jìn)一步探討。

HCC惡性程度高，常呈浸潤(rùn)性生長(zhǎng)。HCC血管侵犯是腫瘤肝內(nèi)播散及轉(zhuǎn)移的重要信號(hào)，也與術(shù)后復(fù)發(fā)密切相關(guān)，包括肉眼可見的大血管侵犯及鏡下微血管侵犯。隨著診斷技術(shù)的進(jìn)步，直徑≤3.0 cm的肝癌(小肝癌)的檢出率日益提高，由于其治療可獲得較好的臨床療效，目前已經(jīng)成為臨床研究的重點(diǎn)。肝切除術(shù)是治療HCC的有效方法，但由于原發(fā)腫瘤的肝內(nèi)轉(zhuǎn)移和多中心發(fā)生，患者術(shù)后較高的復(fù)發(fā)率嚴(yán)重影響遠(yuǎn)期療效，其中絕大多數(shù)患者的死亡與復(fù)發(fā)相關(guān)。微血管侵犯是小肝癌肝內(nèi)轉(zhuǎn)移的直接證據(jù)，是影響術(shù)后復(fù)發(fā)和患者預(yù)后最重要的危險(xiǎn)因素。目前也有部分關(guān)于Gd-EOB-DTPA增強(qiáng)MRI與微血管侵犯相關(guān)的研究報(bào)道。Kim等[60]研究了58例HCC患者(病灶直徑均≤2.0 cm)，結(jié)果表明具有典型Gd-EOB-DTPA增強(qiáng)MRI表現(xiàn)且直徑為1.1～2.0 cm的小肝癌多數(shù)有微血管侵犯。Kim等[61]的研究表明，肝膽期呈高信號(hào)改變的HCC病灶，微血管侵犯比例較低信號(hào)病灶低。肝膽期HCC病灶周圍低信號(hào)則提示微血管侵犯可能，其診斷敏感度較低(38.3%)，但特異度較高(93.2%)[62]；以上研究結(jié)果提示Gd-EOB-DTPA增強(qiáng)MRI對(duì)HCC微血管侵犯有一定的診斷價(jià)值。

術(shù)后評(píng)價(jià)

HCC術(shù)后隨訪復(fù)查對(duì)患者療效評(píng)價(jià)及預(yù)后非常重要。目前也有不少關(guān)于Gd-EOB-DTPA增強(qiáng)MRI在這方面的研究報(bào)道。Yoon等[63]對(duì)經(jīng)射頻消融治療的HCC患者進(jìn)行隨訪，發(fā)現(xiàn)Gd-EOB-DTPA增強(qiáng)MRI對(duì)存活和復(fù)發(fā)病灶的診斷優(yōu)于MSCT。但也有研究者發(fā)現(xiàn)，一些良性病變?cè)诟文懫诒憩F(xiàn)為低信號(hào)，容易與存活灶或腫瘤復(fù)發(fā)轉(zhuǎn)移灶混淆[64]。Seidensticker等[65]對(duì)接受放射治療的肝癌患者進(jìn)行隨訪研究，將Gd-EOB-DTPA增強(qiáng)MRI肝膽期圖像與其接受放射治療的三維立體數(shù)據(jù)進(jìn)行對(duì)照分析，以MRI信號(hào)為橋梁，探索照射劑量與病灶周邊肝實(shí)質(zhì)損傷之間的關(guān)系，結(jié)果發(fā)現(xiàn)肝膽期圖像對(duì)HCC病灶邊界顯示更為清晰，腫瘤直徑及體積的測(cè)量更精確，對(duì)侵犯、包繞血管的判斷更明確，有利于評(píng)估療效和病情。

綜上所述，Gd-EOB-DTPA增強(qiáng)MRI在肝臟局灶性病變的診斷、鑒別診斷、預(yù)后及療效評(píng)價(jià)方面均具有重要作用，并顯示出其相對(duì)于其他檢查方法的優(yōu)勢(shì)。既往研究已經(jīng)明確了肝臟局灶性病變Gd-EOB-DTPA增強(qiáng)MRI的典型影像學(xué)表現(xiàn)，而對(duì)于不典型病灶的影像學(xué)表現(xiàn)及其發(fā)生機(jī)制是未來(lái)的研究方向之一。需要補(bǔ)充的是，盡管一再?gòu)?qiáng)調(diào)Gd-EOB-DTPA增強(qiáng)MRI肝膽期成像的診斷價(jià)值，病灶的定性診斷還需結(jié)合其它序列及臨床進(jìn)行綜合判斷。

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610041成都，四川大學(xué)華西醫(yī)院放射科

張薇薇(1981-)，女，山西人，主治醫(yī)師，主要從事腹部影像診斷研究工作。

宋彬，E-mail:cjr.songbin@vip.163.com

國(guó)家自然科學(xué)基金面上項(xiàng)目資助項(xiàng)目(81171338；81471658)

R575; R445.2

A

1000-0313(2016)01-0044-05

10.13609/j.cnki.1000-0313.2016.01.011

2015-10-23

2015-12-04)