Yedavalli Vivek, Sammet Steffen
Department of Diagnostic Radiology, Advocate Illinois Masonic Medical Center, Chicago, IL.
Department of Radiology, University of Chicago, Chicago, IL.
J Neuroimaging. 2017 Nov;27(6):570-576. doi: 10.1111/jon.12446. Epub 2017 May 17.
Intra-arterial recanalization postprocedural imaging in stroke patients can result in diagnostic complications due to hyperdensities on noncontrast computed tomography (CT), which may represent either contrast extravasation or intracranial hemorrhage. If these lesions are hemorrhage, then they are risk factors becoming symptomatic, which, if not distinguished, can alter clinical management. We investigate the effects of iodinated contrast on postprocedural magnetic resonance imaging (MRI) and prevalence of equivocal imaging interpretations of postprocedural extravasated contrast versus hemorrhage while identifying protocol pitfalls.
We identified 10 patients diagnosed with ischemic stroke who underwent intra-arterial recanalization in a 5-year period. These patients demonstrated a hyperdensity on a postprocedural CT within 24 hours, underwent an MRI within 48 hours, and an additional confirmatory noncontrast CT at least 72 hours postprocedure.
Postprocedural MRI in all 10 stroke patients demonstrated T - and T -relaxation time changes due to residual iodine contrast agents. This lead to false positive postprocedural hemorrhage MRI interpretations in 2/10 patients, 3/10 false negative interpretations of contrast extravasation, and 5/10 equivocal interpretations suggesting extravasation or hemorrhage. Of these five cases, two were performed with gadolinium.
MRI done within 48 hours postprocedure can lead to false positive hemorrhage or false negative contrast extravasation interpretations in stroke patients possibly due to effects from the administered angiographic contrast. Additionally, MRI should be done both after 72 hours for confirmation and without gadolinium contrast as the effects of the gadolinium contrast and residual angiographic contrast could lead to misdiagnosis.
卒中患者动脉内再通术后成像可能因非增强计算机断层扫描（CT）上的高密度影而导致诊断并发症，这些高密度影可能代表造影剂外渗或颅内出血。如果这些病变是出血，那么它们就是出现症状的危险因素，若无法区分，可能会改变临床治疗方案。我们研究了碘化造影剂对术后磁共振成像（MRI）的影响，以及术后造影剂外渗与出血的影像学解释不明确的发生率，同时找出方案中的缺陷。
我们确定了10例在5年期间接受动脉内再通治疗的缺血性卒中患者。这些患者在术后24小时内的CT上显示有高密度影，在48小时内接受了MRI检查，并在术后至少72小时进行了额外的确诊性非增强CT检查。
所有10例卒中患者的术后MRI均显示由于残留碘造影剂导致T1和T2弛豫时间改变。这导致2/10的患者术后MRI对出血的解释出现假阳性，3/10的患者对造影剂外渗的解释出现假阴性，5/10的患者解释不明确，提示有外渗或出血。在这5例中，有2例使用了钆对比剂。
术后48小时内进行的MRI可能会导致卒中患者对出血的解释出现假阳性或对造影剂外渗的解释出现假阴性，这可能是由于血管造影剂的影响。此外，为了确诊，MRI应在72小时后进行，且不使用钆对比剂，因为钆对比剂和残留血管造影剂的影响可能会导致误诊。
