18F-FDG PET/CT在皮革胃與胃充盈不良鑒別診斷中的應(yīng)用價值
程兵謝新立韓星敏劉保平韓軍
(鄭州大學(xué)第一附屬醫(yī)院核醫(yī)學(xué)科河南鄭州450052)
【摘要】目的研究皮革胃的(18)F-FDG PET/CT圖像特點(diǎn),探討(18)F-FDG PET/CT在皮革胃與胃充盈不良鑒別診斷中的應(yīng)用價值。方法回顧性分析18例經(jīng)病理證實(shí)的皮革胃患者的(18)F-FDG PET/CT圖像特征,統(tǒng)計胃壁SUVmax,并與46例胃充盈不良的體檢者進(jìn)行比較。結(jié)果18例皮革胃患者中,有12例胃FDG攝取不高或僅有輕度攝取。PET/CT能明確診斷胃癌者僅9例,誤診為生理性攝取者2例,7例結(jié)果不能與生理性攝取或炎癥鑒別。皮革胃與胃充盈不良者兩組間補(bǔ)充飲水前SUVmax差異無統(tǒng)計學(xué)意義(Z =-0. 829,P =0. 407);補(bǔ)充飲水后皮革胃組SUVmax變化不明顯,而胃充盈不良者胃壁FDG攝取減低,兩組間SUVmax差異有統(tǒng)計學(xué)意義(Z =-5. 126,P =0. 001)。結(jié)論(18)F-FDG PET/CT檢查對皮革胃FDG的攝取與胃充盈不良時胃壁的FDG生理性攝取鑒別困難,補(bǔ)充飲水是鑒別兩者的簡單方法。對CT懷疑胃壁增厚患者,建議補(bǔ)充飲水后再次進(jìn)行(18)F-FDG PET/CT檢查,以避免漏診。
【關(guān)鍵詞】胃腫瘤;皮革胃;計算機(jī)斷層掃描;正電子發(fā)射型計算機(jī)斷層顯像;(18)F-FDG
皮革胃是一種特殊類型的進(jìn)展期胃癌,又稱彌漫性浸潤性胃癌,腫瘤細(xì)胞在胃壁內(nèi)彌漫性浸潤性生長,致使胃壁彌漫性增厚,而黏膜表面平坦,不形成大的潰瘍及向腔內(nèi)突起的腫瘤,故胃鏡診斷較困難,患者預(yù)后差,5年生存率低[1-3]。CT檢查對皮革胃診斷具有重要的價值[4]。目前18F-FDG PET/CT在胃癌的診斷中應(yīng)用很廣泛,但針對皮革胃的應(yīng)用報道較少。本文回顧性分析2010年12月至2014年8月18例皮革胃患者18F-FDG PET/CT顯像特征,并與胃充盈欠佳的體檢者胃壁18F-FDG PET/CT顯像結(jié)果進(jìn)行比較。
1.1一般資料選取2010年12月至2014年8月鄭州大學(xué)第一附屬醫(yī)院進(jìn)行PET/CT檢查的18例皮革胃患者。其中男12例,女6例,年齡23~89歲,中位年齡63歲。主要臨床表現(xiàn)有納差、上腹不適、消瘦及上腹包塊等。所有患者診斷均已經(jīng)胃鏡、穿刺活檢或手術(shù)病理證實(shí)。其中胃低分化腺癌13例,印戒細(xì)胞癌3例,黏液細(xì)胞癌2例。
對照組為46例胃充盈不良的健康體檢者,其中男
39例,女7例,年齡24~91歲,中位年齡53歲。胃充盈不良原因包括患者未按要求飲水或飲水量不足,未能使胃腔充分?jǐn)U張。所有對照組隨診均未發(fā)現(xiàn)胃部惡性腫瘤。
1.2儀器與顯像劑顯像儀器為德國西門子公司生產(chǎn)的Biograph 64 Truepoint PET/CT。顯像劑18F-FDG是由日本住友公司HM.20醫(yī)用回旋加速器生產(chǎn)的18F經(jīng)北京派特科技有限公司生產(chǎn)的PET-FDG-IT-1自動合成模塊合成,高壓液相層析測定18F-FDG放射化學(xué)純度>95%。
1.3顯像方法與顯像條件檢查前患者空腹4~6 h以上,檢查前測量末梢血糖<11. 11 mmol/L,若患者血糖>11. 11 mmol/L,則應(yīng)皮下注射適量胰島素以降低血糖濃度。根據(jù)患者的身高、體質(zhì)量,靜脈注射18F-FDG 296~370 MBq(8~10 mCi),注射劑量0. 12 mCi/kg。注射顯像劑后要求患者飲水至少500 ml,在安靜、避光的環(huán)境中平臥休息60 min,檢查前囑患者排空膀胱。
所有人員均行18F-FDG PET/CT全體部顯像。自
患者顱頂?shù)诫p側(cè)大腿中部,先行螺旋CT掃描。CT掃描條件:電流100~250 mA,管電壓120 kV,0. 8 s/周。后以2. 5 min/床位進(jìn)行PET三維掃描。采集數(shù)據(jù)采用CT進(jìn)行衰減校正,然后行迭代法重建,重建圖像在Syngo工作站上與CT圖像進(jìn)行融合,分別得到冠狀面、矢狀面和橫斷面CT、PET及PET/CT融合圖像。比較兩組間胃壁SUVmax及胃/肝SUVmax比值差異。對胃腔充盈不良者均在補(bǔ)充飲水后復(fù)查PET/CT。
1.4圖像分析和診斷由PET/CT中心具有豐富經(jīng)驗(yàn)的3位高年資核醫(yī)學(xué)科醫(yī)師閱片,對結(jié)果進(jìn)行視覺分析和半定量分析。視覺分析以病灶放射性濃聚程度高于周圍正常組織者視為陽性。放射性濃聚程度略高于周圍正常組織但低于縱隔水平視為輕度攝取。放射性濃聚程度大于或等于縱隔水平但小于肝臟濃聚程度視為中度攝取,高于肝臟攝取程度視為高攝取。在病灶放射性濃聚的位置勾畫ROI,由軟件自動計算獲得SUV,本研究取SUVmax作為分析指標(biāo),以SUVmax≥2. 5作為判斷標(biāo)準(zhǔn)。
1.5統(tǒng)計學(xué)處理所有數(shù)據(jù)使用SPSS 17. 0統(tǒng)計軟件包處理,定量資料用(±s)表示,采用配對樣本t檢驗(yàn)及兩獨(dú)立樣本非參數(shù)檢驗(yàn),P<0. 05為差異有統(tǒng)計學(xué)意義。
2.1手術(shù)及病理結(jié)果18例患者均由病理證實(shí),其中9例行胃全切治療。剩余9例接受化療。病理:胃低分化腺癌13例,印戒細(xì)胞癌3例,黏液腺癌2例。其中9例伴有肝胃間淋巴結(jié)轉(zhuǎn)移,3例發(fā)生腹膜后淋巴結(jié)轉(zhuǎn)移,3例發(fā)生肝轉(zhuǎn)移,5例發(fā)生腹膜轉(zhuǎn)移及腹水。
2.2病灶的SUVmax值、胃腔及PET顯像情況18例皮革胃患者FDG攝取差異較大,12例患者胃FDG攝取不高或僅有輕度攝取。所有患者均有不同程度的胃壁增厚,胃壁僵硬,胃腔縮小。見圖1、2。
對18例皮革胃患者經(jīng)PET/CT能明確診斷胃癌者僅9例(均伴轉(zhuǎn)移灶),誤診為胃壁生理性攝取者2例,其余7例PET/CT影像結(jié)果不能與胃壁生理性攝取或炎癥鑒別。18例皮革胃患者SUVmax值為2. 08~16. 1(5. 10±3. 55),補(bǔ)充飲水后SUVmax值為1. 80~15. 7(4. 91±3. 71),前后SUVmax值差異無統(tǒng)計學(xué)意義(t = 1. 23,P =0. 235)。46例胃充盈不良體檢者SUVmax值為2. 30~9. 60(4. 71±1. 40)。補(bǔ)充飲水后胃腔充盈良好,SUVmax值為0. 70~2. 80(1. 63±0. 59),胃壁SUV-max較補(bǔ)充飲水前減低,差異有統(tǒng)計學(xué)意義(t =13. 09,P =0. 001)。
補(bǔ)充飲水前皮革胃患者與胃充盈不良兩組間的SUVmax差異無統(tǒng)計學(xué)意義(Z =-0. 829,P = 0. 407),補(bǔ)充飲水后皮革胃組胃壁SUVmax值變化不明顯,而胃充盈不良者胃壁FDG攝取減低,兩組間SUVmax差異有統(tǒng)計學(xué)意義(Z =-5. 126,P = 0. 001)。
圖1 皮革胃患者PET/CT圖像
圖2 補(bǔ)充飲水后增強(qiáng)CT圖像
2.3病理分化程度與PET顯像的關(guān)系2例黏液腺癌和2例印戒細(xì)胞癌為低攝取,1例印戒細(xì)胞癌和5例低分化腺癌為輕度攝取,8例低分化腺癌為高攝取。
18F-FDG是目前應(yīng)用最廣泛的腫瘤顯像劑,其顯像原理是腫瘤細(xì)胞能大量攝取葡萄糖,而18F-FDG作為葡萄糖類似物,被葡萄糖轉(zhuǎn)移酶轉(zhuǎn)運(yùn)至細(xì)胞內(nèi),在己糖激酶作用下轉(zhuǎn)化為6-磷酸脫氧葡萄糖,不能夠進(jìn)一步參與葡萄糖代謝而滯留在細(xì)胞內(nèi),從而對腫瘤進(jìn)行顯像。近年來PET/CT在胃癌診斷中應(yīng)用日益廣泛。但既往有文獻(xiàn)報道PET/CT對胃癌的診斷有局限性。本研究發(fā)現(xiàn),對放射性分布濃聚的淋巴結(jié)、腹膜和肝臟的轉(zhuǎn)移灶18F-FDG PET/CT顯像能靈敏地發(fā)現(xiàn),但結(jié)合胃壁顯像情況能明確診斷者僅占50%。18例皮革胃患者胃壁FDG攝取差異較大,有12例胃FDG攝取不高或僅有輕度攝取。不易與胃充盈不良時胃壁的FDG輕度攝取進(jìn)行鑒別而造成誤診,與國外報道相近[5-8]。在胃壁充盈不充分或未充盈的情況下,胃壁可以呈現(xiàn)出FDG的生理性攝取,主要由于平滑肌的蠕動造成[9]。CT圖像能較好地顯示胃壁厚度、柔韌度及與周圍組織的關(guān)系,但只有在氣體、水或陽性造影劑使胃腔適當(dāng)擴(kuò)張后,才能正確地評估胃壁的厚度及柔韌度。當(dāng)胃腔未能充分?jǐn)U張時,CT的診斷則較為困難[10-14]。皮革胃典型CT表現(xiàn)是局灶性或彌漫性胃壁增厚[15]。本研究中18例患者CT也均表現(xiàn)為胃壁僵硬、增厚,而且在患者補(bǔ)充飲水前、后胃腔擴(kuò)張情況及胃壁FDG攝取無明顯變化。而46例胃充盈不良體檢者補(bǔ)充飲水后胃腔充盈良好,胃壁SUVmax較補(bǔ)充飲水前顯著減低。因此若補(bǔ)充飲水后CT仍顯示有明顯的胃腔狹窄,而且胃壁FDG攝取無明顯變化,有助于皮革胃的診斷。
綜上所述,18F-FDG PET/CT檢查對皮革胃FDG的攝取與胃充盈不良時胃壁的FDG生理性攝取鑒別困難,補(bǔ)充飲水是鑒別兩者的簡單方法。對CT懷疑胃壁增厚患者,建議補(bǔ)充飲水后再次進(jìn)行18F-FDG PET/CT檢查,以避免漏診。
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Application value of18F-FDG PET/CT in differential diagnosis of linitis plastica and normal gastric cavity with poorly water filling
Cheng Bing,Xie Xinli,Han Xingmin,Liu Baoping,Han Jun
(Department of Nuclear Medicine,the First Affiliated Hospital of Zhengzhou University,Zhengzhou 450052,China)
【Abstract】Objective To clarify the characteristics of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography((18)F-FDG PET/CT)findings of linitis plastica,and explore the application value of(18)F-FDG PET/CT in differential diagnosis of linitis plastica and normal gastric cavity with poorly water filling.Methods The characteristics of(18)FFDG PET/CT findings in 18 patients with linitis plastica confirmed by pathology.The standardized uptake value-maximum(SUVmax)of the gastric wall was calculated and compared with 46 cases of normal gastric cavity with poorly water filling.Results Among the 18 cases of linitis plastica,12 cases showed low to moderate level of(18)F-FDG uptake.9 cases of linitis plastica were confirmed by PET/CT and 2 cases were misdiagnosed as physiological uptake.Other 7 cases could not be differentiated from physiological uptake or inflammatory.There was no significant difference in SUVmax before water intake between linitis plastica and normal gastric cavity(Z =-0. 829,P =0. 407).After water intake,the change of SUVmax in linitis plastica group was not obvious,and the FDG intake of gastric wall in patients with normal gastric cavity with poorly water filling was significantly decreased(Z =-5. 126,P = 0. 001).Conclusion(18)F-FDG PET/CT could not effectively distinguish physiological uptake ofbook=20,ebook=518poorly gastric filling from linitis plastica.Water intake may be useful to prevent misdiagnosis.The diagnostic value of this technique based on SUVmax is limited.For patients with gastric wall thickening diagnosed by CT,(18)F-FDG PET/CT examination after water intake may be the good choice to advoid missed diagnosis.
【Key words】gastric carcinoma; linitis plastic; computed tomography; positron emission tomography; fluorine-18 fluorodeoxyglucose
(收稿日期:2015-03-23)
通訊作者:劉保平,E-mail: Liubp5000@ sina.com。
doi:10.3969/j.issn.1004-437X.2015.08.007
【中圖分類號】R 735.2