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原發(fā)性開角型青光眼中樞視通路形態(tài)和功能的磁共振成像研究

發(fā)布時間:2018-05-05 03:21

  本文選題:原發(fā)性開角型青光眼 + 視網(wǎng)膜神經(jīng)纖維層厚度。 參考:《第三軍醫(yī)大學》2014年博士論文


【摘要】:研究背景和目的 青光眼是世界范圍內不可逆性致盲的首要原因,以進行性的視網(wǎng)膜神經(jīng)節(jié)細胞(retinal ganglion cells,RGCs)及其軸突丟失為主要特征。原發(fā)性開角型青光眼(primaryopen angle glaucoma, POAG)是青光眼的主要表現(xiàn)類型之一,其發(fā)病隱匿,潛在危險性更大。盡管RGCs漸進性丟失是其主要的病理特征,但越來越多的組織學及影像學研究證實可能整個視覺通路均受累及,包括RGCs、外側膝狀體(lateral geniculatenucleus, LGN)以及初級視皮質(primary visual cortex, V1)等。目前POAG被認為是由環(huán)境和遺傳因素導致的復雜性性視通路病變,但具體的發(fā)病機制仍需進一步探討。 近年來采用磁共振成像(magnetic resonance imaging,MRI)技術對POAG視覺通路損害的研究引起了廣泛關注。該技術可以從視覺皮質結構、視通路白質纖維束、任務態(tài)和靜息態(tài)的腦功能等諸多角度揭示POAG視覺通路的改變情況。但既往的MRI研究多關注于POAG的中晚期,疾病早期的中樞視覺通路是否改變仍不明了,而且POAG患者皮質形態(tài)的改變進程以及POAG早期靜息狀態(tài)下功能的改變在疾病神經(jīng)機制中起到的作用尚不清楚。因此,本項研究基于視皮質通路多參數(shù)的形態(tài)分析以及靜息態(tài)功能磁共振(resting-state functional magnetic resonance imaging, R-fMRI)的方法,研究POAG患者特別是疾病早期中樞視區(qū)的皮質結構和相關腦區(qū)的神經(jīng)元功能改變,探討該病可能的發(fā)病機制并為臨床治療提供有效的依據(jù)。 材料和方法 1.采集36例雙眼POAG患者和40例匹配的正常志愿者的3D T1加權高分辨率MRI數(shù)據(jù),采用CIVIET軟件(1.1.9版本,蒙特利爾神經(jīng)病研究所,加拿大)進行全腦皮質厚度分析,檢測POAG患者可能存在的皮質厚度改變并與視網(wǎng)膜神經(jīng)纖維層(retinal nerve fiber layer, RNFL)厚度做相關分析。隨后POAG患者組被分成輕重兩個亞組,比較視區(qū)皮質厚度隨疾病嚴重程度的改變情況。 2.采集20例早期(輕度組)、17例中晚期(重度組)的雙眼POAG患者和20例匹配的健康志愿者(對照組)的TI加權高分辨率MRI數(shù)據(jù);诟信d趣區(qū)(regionof interest, ROI)分析的方法V1、V2(紋前皮質)和V5/MT+(顳中回視區(qū))的皮質厚度,數(shù)據(jù)處理由FreeSurfer軟件(5.3.0版本,麻省總院,波士頓,美國)完成。比較三組間的皮質厚度差異,并分析各ROI雙側的皮質厚度與雙側的RNFL厚度和視野MD值的相關性。 3.采用第二部分的MRI數(shù)據(jù),按照視網(wǎng)膜映射(中心視角10°)把V1和V2分別細分為前后兩個亞區(qū),同樣納入V5/MT+區(qū)作為ROI。分析V1和V2前、后亞區(qū)以及V5/MT+區(qū)的多參數(shù)皮質結構改變。比較三組間形態(tài)學指標的差異,并分析皮質厚度與關鍵性臨床指標之間的相關性。 4.采集21例POAG早期患者和20例健康志愿者的R-fMRI和高分辨率T1結構像數(shù)據(jù),計算全腦比率低頻振蕩波幅值(fALFF)得到活動改變腦區(qū),并把fALFF改變區(qū)(左側楔前葉)與雙側V1、V2、V5/MT+區(qū)一并納入作為ROI,分析與全腦功能連接的強度改變。 結果: 1.全腦皮質厚度分析結果:POAG組在雙側的距狀溝前份的視皮質厚度明顯變。ㄓ覀鹊腂A17,左側的BA17和BA18)。另有較小的皮質厚度減低區(qū)呈現(xiàn)在左側的顳中回(BA37)和梭狀回(BA19)。相關分析:左側和右側的距狀溝皮質厚度與RNFL厚度呈正相關(左側r=0.44,P=0.01;右側r=0.38;P=0.03)。重度亞組左側和右側的RNFL厚度以及皮質厚度與輕度亞組比較均顯著變薄。 RNFL厚度左側:59.2±18.1vs.77.3±13.0μm(P=0.001);右側:59.2±14.5vs.73.3±19.0μm(P=0.020);皮質厚度左側:2.46±0.18vs.2.59±0.10mm(P=0.014);右側:2.56±0.16vs.2.70±0.14mm(P=0.009)。 2.基于ROI的皮質厚度分析結果:與正常組比較,重度組左側的V1和雙側的V2以及V5/MT+區(qū)皮質厚度明顯減低,輕度組雙側的V5/MT+區(qū)皮質厚度顯著變。蝗M間的平均皮質厚度隨疾病加重呈減低趨勢,重度組雙側的V2區(qū)皮質厚度較正常組和輕度組均明顯變薄。雙側的V2區(qū)(r=0.38,P=0.02)和V5/MT+區(qū)(r=0.44,P=0.006)的皮質厚度與雙側的RNFL厚度呈正相關。雙側所有ROI的皮質厚度均與雙側的視野MD值呈正相關(V1:r=0.34,P=0.04;V2:r=0.42,P=0.009;V5/MT+:r=0.37,P=0.03)。 3.基于ROI的形態(tài)學分析結果:皮質厚度:與正常對照組比較,重度組的V1前亞區(qū)(P=0.010),V2前亞區(qū)(P=0.011)和V5/MT+(P=0.016)區(qū)皮質厚度顯著減低,輕度組V5/MT+區(qū)皮質厚度明顯變。≒=0.025)。重度組的V2后亞區(qū)皮質厚度較輕度組(P=0.002)和正常對照組(P=0.000)均顯著減低。重度組V2后亞區(qū)灰質體積較正常對照組(P=0.001)和輕度組(P=0.034)均顯著性減少。重度組V5/MT+區(qū)的平均曲率較正常組(P=0.031)顯著改變。但三組間表面積無顯著差異(P0.05)。皮質厚度相關分析:V5/MT+區(qū)與RNFL厚度正相關(r=0.42,P=0.01)。重度組V1前亞區(qū)與RNFL厚度有相關趨勢(r=0.46,P=0.08)。 4.全腦靜息態(tài)fALFF與功能連接分析結果:與對照組比較,POAG早期患者的左側楔前葉(BA7),左側角回(BA39)fALFF值呈顯著減低(P 0.05,AlphaSim校正)。功能連接結果顯示患者組與左側楔前葉(BA7)和雙側V5/MT+連接強度較對照組減低的區(qū)域主要包括:動眼區(qū)(BA8)、額回(BA9、BA10、BA11)、前扣帶回(BA24)、左側小腦后葉和小部分顳中回區(qū)域(BA39),這些腦區(qū)基本與背側注意網(wǎng)絡一致。與V1和V2區(qū)連接強度減低的區(qū)域包括左側前扣帶回和左側小腦后葉;颊呓M未發(fā)現(xiàn)fALFF或功能連接強度較對照組增高的區(qū)域。 結論: 1.全腦皮質厚度分析發(fā)現(xiàn)皮質改變區(qū)域主要位于距狀溝周圍皮質(BA17和BA18區(qū)),并且與臨床關鍵指標RNFL厚度呈正相關,說明皮質厚度分析結果準確可靠,可作為判斷POAG患者疾病嚴重程度的影像學指標。POAG患者視覺皮質萎縮揭示視覺中樞參與了其中的發(fā)病機制,但是基于全腦的皮質厚度分析不能提供解剖或者功能具體分區(qū)內的整體特性,也無法進行個體化的診斷。 2.基于ROI的皮質厚度分析發(fā)現(xiàn)POAG早期患者V5/MT+區(qū)存在皮質萎縮,并顯示隨疾病嚴重程度的增加視皮質厚度的呈進行性減低。結果提示POAG早期視皮質就已參與了其中的病生機制,為臨床早期干預治療和指定策略防止腦神經(jīng)損傷提供了影像學證據(jù)。 3.基于視網(wǎng)膜皮質映射的形態(tài)學結構分析能夠提供更多的POAG患者視皮質改變信息,結果表明皮質厚度是POAG患者視皮質改變的敏感性和可靠性指標,,且V1和V2細分亞區(qū)之后更能客觀地評價視區(qū)內的改變。結果提示V5/MT+區(qū)可能是POAG早期視皮質結構改變的關鍵腦區(qū)。 4. R-fMRI結果顯示POAG早期患者的背側注意網(wǎng)絡受到了影響。楔前葉(BA7)和V5/MT+可能是POAG早期患者功能改變的關鍵腦區(qū),其所處的背側視覺通道在POAG早期的發(fā)病機制中起到了關鍵的作用。
[Abstract]:Background and purpose of the study


Primary open angle glaucoma ( POAG ) is one of the main manifestations of glaucoma . Primary open angle glaucoma ( POAG ) is one of the main manifestations of glaucoma .


In recent years , magnetic resonance imaging ( MRI ) has been used to study the changes of POAG ' s visual pathway .


Materials and Methods


1 . 3D T1 weighted high - resolution MRI data of 36 patients with POAG and 40 matched normal volunteers were collected . The thickness of cortex was analyzed by CIVIET software ( Version 1.1 . 9 , Montreal Neuropathy Institute , Canada ) , and the thickness of retinal nerve fiber layer ( RNFL ) was analyzed .


2 . The cortical thickness of 20 cases ( mild group ) , 17 patients with moderate and late ( severe group ) binocular POAG and 20 matched healthy volunteers ( control group ) were collected . Data processing was performed by FreeSurfer software ( version 5.3 . 0 , Massachusetts General Hospital , Boston , USA ) .


3 . Using MRI data of the second part , V1 and V2 were subdivided into two sub - regions in the anterior and posterior regions according to the retinal mapping ( central viewing angle of 10 擄 ) , and also included in the V5 / MT + region as the ROI . The changes of multi - parameter cortical structures in the anterior , posterior and V5 / MT + regions of V1 and V2 were analyzed . The differences of the morphological indexes between the three groups were compared and the correlation between cortical thickness and key clinical indexes was analyzed .


4 . In 21 patients with POAG and 20 healthy volunteers , R - and high - resolution T1 - structure image data were collected , and the whole - brain - ratio low - frequency oscillation amplitude ( fALFF ) was calculated to change the brain area , and the fALFF - changing area ( left wedge anterior leaflet ) was combined with bilateral V1 , V2 , V5 / MT + region as ROI , and the intensity change of all - brain functional connection was analyzed .


Results :


1 . Results of all - cerebral cortex thickness analysis : The visual cortex thickness of POAG group was significantly thinner ( BA17 on the right side , BA17 and BA18 on the left side ) in the anterior part of the double - sided groove . There was also a small cortical thickness reduction area on the left temporal gyrus ( BA37 ) and fusiform gyrus ( BA19 ) . Correlation analysis showed that the thickness of the left and right margin sulcus cortex was positively correlated with the thickness of RNFL ( r = 0.44 , P = 0.01 ) .
r = 0.38 on the right ;
P=0.03). The RNFL thickness and cortical thickness in the left and right sides of the severe subgroup were significantly thinner compared to mild sub - groups . The thickness of RNFL was 59.2 鹵 18.1 vs . 77.3 鹵 13.0 渭m ( P = 0.001 ) .
Right : 59.2 鹵 14.5 vs . 73.3 鹵 19.0渭m ( P = 0.020 ) ;
Left side of cortical thickness : 2.46 鹵 0.18 vs . 2.59 鹵 0.10 mm ( P = 0.014 ) ;
Right : 2.56 鹵 0.16 vs . 2.70 鹵 0.14 mm ( P = 0.00009 ) .


2 . Results of cortical thickness analysis based on ROI : Compared with the normal group , the cortical thickness of V1 and bilateral V2 and V5 / MT + area on the left side of the severe group were obviously reduced , and the thickness of the cortex of V5 / MT + area in the mild group was significantly thinner ;
The cortical thickness of the two sides was positively correlated with the thickness of RNFL on the bilateral side ( r = 0.38 , P = 0.02 ) and V5 / MT + region ( r = 0.44 , P = 0.006 ) . The cortical thickness of all ROI on both sides was positively correlated with the MD value of bilateral vision ( V1 : r = 0.34 , P = 0.04 ) .
V2錛歳=0.42,P=0.009錛

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