MR-DWI在腰椎間盤變性診斷中的價值

Diffusion-weighted MR Imaging with Apparent Diffusion Coefficient and Maps in Human Lumbar Intervertebral Disc Degeneration

目的結合常規MR成像,對腰椎問盤變性的MR彌散加權成像(diffusion weighted imaging,DWI)進行分析,探討MR-DWI在腰椎間盤變性診斷中的價値。方法前瞻性對40例腰椎間盤檢查者,共200個腰椎間盤進行分析研究;其中正常腰椎間盤73個,變性椎間盤127個。所有病例均行常規MR檢查,包括失狀位T2WI,同時均行不同b値的MR弼散加權成像,b値分別選擇3OOs/mm^(2)、500 s/mm^(2)、1000 s/mm^(2);彌散加權成像採用失狀位掃描,利用工作站的Functool 2後處理軟體獲得每個椎間盤的表觀彌散係數(apparent diffusion coefficient,ADC)值,採用SPSS10.0軟體進行統計學分析,P<0.05爲顯著意義。結果1.73個正常椎間盤和127個變性椎間盤在b値爲3OOs/mm^(2)時,ADC値分別爲1.93×10^(-3)mm^(2)/s和1.49×10^(-3)mm^(2)/s,P<0.05;在b値爲500 s/mm^(2)時,ADC値分別爲1.88×10^(-3)mm^(2)/s和1.27×10^(-3)mm^(2)/s,P<0.05;在b値爲1000 s/mm^(2)時,ADC値分別爲1.48×10^(-3)mm^(2)/s和0.84×10^(-3)mm^(2)/s,P<0.05。2.200個椎間盤在不同b値彩色ADC圖中髓核顯示結果分析表明,當b値爲1000 s/mm^(2)時,髓核顯示最清楚,且與纖維環易分辨;當b値爲500 s/mm^(2)時,髓核顯示較模糊,與纖維環部份相融合,不易反映髓核的真實變化;當b値爲300 s/mm^(2)時,髓核顯示不清楚,髓核與纖維環之間不易分辨,與小b値受灌注影響大,不能有效反應水分子的彌散運動有關。3.在127個變性椎間盤中,表現爲T2WI信號正常,但DWI的ADC値下降,且髓核量減少者爲27個,佔21%,P<0.05>表明MR-DWI的敏感性較常規T2WI高。結論在腰椎間盤檢查時,應將MR-DWI掃描與常規MR檢查緊密結合,對提高腰椎間盤變性的診斷具有一定的價値;並以b値爲1000 s/mm^(2)時行DWI檢查首選,既可瞭解ADC値的變化,又可較直觀地在其彩色ADC圖中顯示側核和纖維環的變化。

Objective To evaluate diffusion-weighted magnetic resonance(MR)imaging in patients with lumbar intervertebral disc degeneration.Materials and Methods A multishot echo-planar imaging sequence with calculation of apparent diffusion coefficient(ADC)and T2-weighted fast spin-echo imaging on sagittal plane were applied in 40 patients with lumbar intervertebral disc degeneration.Total 200 lumbar intervertebral discs were analyzed by Functool 2 software in the workstation to obtain ADC values with B values of 3OOs/mm^(2),500 s/mm^(2) and 1000 s/mm^(2).Diffusion-weighted images were compared with T2-weighted images with regard to clinical status.Results For B value of 300 s/mm^(2),patients with lumbar intervertebral disc degeneration had abnormal discs(127 of 200)and normal discs(73 of 200),while ADC values were 1.49×10^(-3)mm^(2)/s and 1.93×10^(-3)mm^(2)/s(P<0.05).Meanwhile,ADC values were 1.27×10^(-3)mm^(2)/s and 1.88×10^(-3)mm^(2)/s for B value of 500s/mm^(2)(P<0.05),and 0.84×10^(-3)mm^(2)/s and 1.48×10^(-3)mm^(2)/s for B value of 1000s/mm^(2)(P<0.05).With ADC maps,it has best discrimination ability to show nucleus pulposus and anulus visually for B value of 1000s/mm^(2).When B value is 500s/mm^(2),nucleus pulposus was not so clear and fused with the anulus visually.When B value is 3OOs/mm^(2),it cannot distinct nucleus pulposus with anulus.The results show that it is difficult to observe water diffusion for small B value due to perfusion.In patients with abnormal discs(127),the ADC values decreased(27 of 127)whereas normal signal intensity exhibited on T2-weighted images(P<0.05),which indicated the diffusion-weighted images are more sensitivity than T2-weighted images.Conclusion Diffusion-weighted MR imaging with apparent diffusion coefficient and maps offer a reliable method of assessing early human lumbar intervertebral disc degeneration when used B value of 1000 s/mm.