上咽頭癌の灌流MRI。動脈スピンラベリングとダイナミック造影MRIの比較

Nasopharyngeal carcinoma perfusion MRI: Comparison of arterial spin labeling and dynamic contrast-enhanced MRI.

• Bohan Xiao
• Peiguo Wang
• Yingru Zhao
• Ying Liu
• Zhaoxiang Ye

抄録

上咽頭癌（NPC）灌流の質的・量的評価のための動的造影（DCE）磁気共鳴イメージング（MRI）の代替としての3D動脈スピンラベリング（ASL）の実現可能性を調査するために。NPC灌流レベルの視覚的定性的評価は0～3（0＝正常末梢軟部組織に対する造影なし，3＝正常末梢軟部組織に対する顕著な造影あり）とした．NPCの輪郭の視覚的評価は、0から2の間で採点した（0＝非常に曖昧な輪郭、2＝明確な輪郭）。ASL由来の血流（BF）とDCE-MRI由来の陽性増強積分、増加の最大傾き、減少の最大傾き、およびピークまでの時間（TTP）との比較を、独立標本t検定を用いてNPCと非NPC領域との間で行った。これらのパラメータの診断性能は、受信機操作特性曲線分析により評価した。ASL BFとDCEパラメータの間の相関関係をスピアマン相関分析で評価した．ASLはDCE-MRIよりもNPCの輪郭を記述するための視覚スコアが低かった(P"Zs_200A"<"Zs_200A".001)。NPC領域のASLとDCEのパラメータは、NPC領域以外の領域と有意に異なっていた(P"Zs_200A"<"Zs_200A".001)。ASL BFは、NPCを識別するための受信機動作特性曲線(AUC)0.936の下で最大の面積を示した。すべてのNPC領域と非NPC領域を考慮した場合、ASL BFとDCEパラメータの間に有意な相関が観察された。正の増強積分(r"Zs_200A"="Zs_200A"0.503, P"Zs_200A"<"Zs_200A".001),最大増加勾配(r"Zs_200A"="Zs_200A"0.616, P&#x200A"0.001)616、P"Zs_200A"<"Zs_200A".001）、減少の最大勾配（r"Zs_200A"="Zs_200A"0.380、P"Zs_200A"<"Zs_200A".001）、TTP（r"Zs_200A"="Zs_200A"-0．3次元ASLは造影剤を使用せずにNPCの過灌流を定性的にも定量的にも明らかにすることができた。また、3次元ASLのBFは、半定量的なDCE-MRIパラメータと有意に相関していた。

To investigate the feasibility of 3D arterial spin labeling (ASL) as an alternative to dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) for the qualitative and quantitative evaluation of nasopharyngeal carcinoma (NPC) perfusion.Fifty-two newly diagnosed NPC patients underwent 3D ASL and DCE-MRI scans on a 3.0-T MRI system. The visual qualitative evaluation of the NPC perfusion level was scored from 0 to 3 (0 = no contrast to normal peripheral soft tissue, 3 = pronounced contrast to normal peripheral soft tissue). The visual evaluation of the NPC outline was scored from 0 to 2 (0 = very vague outline, 2 = clear outline). Comparisons of the ASL-derived blood flow (BF) with the DCE-MRI-derived positive enhancement integral, maximum slope of increase, maximum slope of decrease, and time to peak (TTP) were conducted between NPC and non-NPC areas with independent samples t-tests. The diagnostic performance of these parameters was assessed by receiver operating characteristic curve analysis. The correlations between ASL BF and DCE parameters were assessed by Spearman correlation analysis.There was no difference in the visual scores of the NPC perfusion level between the 2 perfusion methods (P= .963). ASL had a lower visual score for describing the outline of NPC than DCE-MRI (P < .001). The ASL and DCE parameters of the NPC areas were significantly different from those of the non-NPC areas (P < .001). The ASL BF showed the largest area under the receiver operating characteristic curve (AUC) of 0.936 for identifying NPC. When all NPC and non-NPC areas were taken into account, significant correlations were observed between the ASL BF and the DCE parameters positive enhancement integral (r = 0.503, P < .001), maximum slope of increase (r = 0.616, P < .001), maximum slope of decrease (r = 0.380, P < .001), and TTP (r = -0.601, P < .001).3D ASL could reveal the hyperperfusion of NPC in a qualitative and quantitative manner without using contrast agent. Additionally, the ASL BF correlated significantly with the semiquantitative DCE-MRI parameters.