Neurology and Stroke Unit, Bufalini Hospital, Cesena, Italy.
IRCCS Istituto delle ScienzeNeurologiche di Bologna, Neurologia e Rete Stroke Metropolitana, OspedaleMaggiore, Bologna, Italy.
Epilepsia. 2022 Oct;63(10):2534-2542. doi: 10.1111/epi.17359. Epub 2022 Jul 20.
Nonconvulsive status epilepticus (NCSE) is misdiagnosed in >50% of cases in the emergency department. Computed tomographic perfusion (CTP) has been implemented in the hyperacute setting to detect seizure-induced hyperperfusion. However, the diagnostic value of CTP is limited by the lack of thresholds for hyperperfusion and high interrater variability. This pilot case-control study aims at identifying the diagnostic value of reverse Tmax (rTmax) in differentiating NCSE from acute ischemic stroke in the hyperacute setting.
We enrolled patients with NCSE (Salzburg criteria-based diagnosis) and stroke cases 1:1 matched for clinical features and time of presentation. CTP standard maps (mean transit time [MTT]-cerebral blood volume-cerebral blood flow [CBF]) and rTmax maps were elaborated and rated by two experts in CTP blinded to the final diagnosis. Hyperperfusion was adjudicated for standard CTP maps as an increase in CBF and a decrease in MTT, and for rTmax as the presence of a black area on 3-, 2-, and 1-s threshold maps. Cronbach alpha was used for interrater agreement; receiver operating curve analysis was run to measure accuracy with area under the curve.
Overall, 34 patients were included (17 NCSE, 17 stroke; time from onset to imaging = 2 h for both groups). People with NCSE were older and more frequently had a history of epilepsy. NCSE patients had hyperperfusion on rTmax maps in 11 of 17 cases versus zero of 17 in stroke. Intra- and interrater reliability was higher for rTmax than for standard CTP maps (κ = 1 vs. κ = .6). rTmax was 82% (95%CI = 67-97%) accurate in predicting NCSE versus stroke in the hyperacute setting. Agreement between neuroimaging and electroencephalography (EEG) was limited at a hemispheric level for standard CTP maps, whereas rTMax had agreement with EEG largely reaching the sublobar level.
rTmax mapping might represent a reliable tool to spot NCSE-induced hyperperfusion with a threshold-based reproducible approach. Further studies are needed for validation and implementation in the differential diagnosis of focal neurological deficit in the hyperacute setting.
非惊厥性癫痫持续状态（NCSE）在急诊科的误诊率超过 50%。在超急性期实施计算机断层灌注（CTP）以检测癫痫诱导的高灌注。然而，CTP 的诊断价值受到高灌注的缺乏和高观察者间变异性的限制。本病例对照研究旨在确定反转 Tmax（rTmax）在超急性期区分 NCSE 与急性缺血性卒中的诊断价值。
我们纳入了符合萨尔斯堡标准诊断的 NCSE 患者和 1：1 临床特征和就诊时间匹配的卒中患者。对 CTP 标准图（平均通过时间 [MTT]-脑血容量-脑血流 [CBF]）和 rTmax 图进行了分析，并由两名对最终诊断不知情的 CTP 专家进行了评分。标准 CTP 图上的高灌注被判定为 CBF 增加和 MTT 减少，rTmax 上的高灌注被判定为 3、2 和 1 秒阈值图上存在黑色区域。Cronbach α 用于评估观察者间的一致性；进行接收者操作曲线分析以测量曲线下面积的准确性。
共有 34 名患者入组（17 名 NCSE，17 名卒中；两组从发病到影像学检查的时间均为 2 小时）。NCSE 患者中有 11 例在 rTmax 图上存在高灌注，而卒中患者中无一例存在高灌注。rTmax 的观察者内和观察者间可靠性均高于标准 CTP 图（κ=1 对 κ=0.6）。在超急性期，rTmax 预测 NCSE 与卒中的准确率为 82%（95%CI=67-97%）。标准 CTP 图在半球水平上与脑电图（EEG）的一致性有限，而 rTMax 与 EEG 的一致性主要达到亚叶水平。
rTmax 图可能是一种可靠的工具，可通过基于阈值的可重复方法发现 NCSE 诱导的高灌注。需要进一步的研究来验证和在超急性期局灶性神经功能缺损的鉴别诊断中实施。
