Kono Kenichi, Shintani Aki, Terada Tomoaki
Department of Neurosurgery, Wakayama Rosai Hospital, 93-1 Kinomoto, Wakayama, 640-8505, Japan,
Acta Neurochir (Wien). 2014 Sep;156(9):1713-9. doi: 10.1007/s00701-014-2142-5. Epub 2014 Jun 3.
Carotid artery stenting (CAS) requires follow-up imaging to assess in-stent restenosis (ISR). This study aimed to determine whether non-enhanced magnetic resonance angiography (NE-MRA) is useful for evaluating ISR.
Between 2009 and 2013, we performed 118 consecutive CAS procedures using the Precise stent (n = 78) and the Carotid Wallstent (n = 40). We reviewed 1.5 T NE-MRA and examined visualization of the stent lumen and the degree of ISR if present. Other imaging modalities were used as references.
NE-MRA performed just after CAS was not able to visualize the stent lumen in all patients because of metal artifacts. In the Carotid Wallstent group, follow-up NE-MRA was available in 22 patients. The stent lumen was visible more than three months after CAS in all patients. Among them, >40 % ISR was observed by other modalities in eight lesions. The degree of restenosis measured by NE-MRA (y%) had a linear relationship with that measured by conventional angiography (x%) (y = 0.97x-0.4, r = 0.79, P = 0.021). In one case among 17 without ISR (6 %), NE-MRA showed false ISR. In the Precise stent group, NE-MRA did not visualize the stent lumen in the follow-up period.
NE-MRA can visualize the stent lumen in the Carotid Wallstent more than three months after CAS, but not in the Precise stent at follow-up. This delayed visualization might depend on endothelialization of the stent lumen. The degree of ISR measured by NE-MRA is comparable to that by conventional angiography. NE-MRA can evaluate ISR after CAS with the Carotid Wallstent (100 % sensitivity and 94 % specificity).
颈动脉支架置入术（CAS）需要进行随访成像以评估支架内再狭窄（ISR）。本研究旨在确定非增强磁共振血管造影（NE-MRA）是否有助于评估ISR。
2009年至2013年期间，我们连续进行了118例CAS手术，使用Precise支架（n = 78）和颈动脉Wallstent支架（n = 40）。我们回顾了1.5T的NE-MRA，并检查了支架内腔的可视化情况以及是否存在ISR及其程度。使用其他成像方式作为参考。
由于金属伪影，CAS术后立即进行的NE-MRA无法在所有患者中显示支架内腔。在颈动脉Wallstent支架组中，22例患者可进行随访NE-MRA。所有患者在CAS术后三个月以上均可看到支架内腔。其中，其他成像方式在8个病变中观察到>40%的ISR。NE-MRA测量的再狭窄程度（y%）与传统血管造影测量的程度（x%）呈线性关系（y = 0.97x - 0.4，r = 0.79，P = 0.021）。在17例无ISR的患者中（6%），有1例NE-MRA显示假阳性ISR。在Precise支架组中，随访期间NE-MRA未显示支架内腔。
NE-MRA可在CAS术后三个月以上显示颈动脉Wallstent支架的内腔，但在随访中无法显示Precise支架的内腔。这种延迟的可视化可能取决于支架内腔的内皮化。NE-MRA测量的ISR程度与传统血管造影相当。NE-MRA可评估颈动脉Wallstent支架CAS术后的ISR（敏感性100%，特异性94%）。
