新生物性脑内出血（ICH）可能会在成像上错误地表明非新生物性ICH。计算机断层扫描（CT）上的相对出血周围水肿（relPHE）已被提出作为区分新生物性与非新生物性ICH的标志物，但尚未外部验证。本研究的目的是评价relPHE在独立患者队列中的区分能力。本单中心回顾性研究纳入了291例接受CT和随访MRI的急性ICH患者。根据随访MRI的诊断将ICH患者分为非新生物性或新生物性ICH。ICH、PHE体积和密度值从半自动分割的CT扫描中获取。通过受试者工作特征（ROC）曲线评估用于区分新生物性ICH的PHE特征。计算出ROC曲线关联的截断值，并在初始队列和验证队列之间进行比较。本研究纳入了116例（39.86％）新生物性ICH患者和175例（60.14％）非新生物性ICH患者。中位数PHE体积、relPHE和经病灶密度调整的relPHE在新生物性ICH患者中显著高于非新生物性ICH患者，所有P值<0.001。relPHE的ROC曲线下面积（AUC）为0.72（95％CI 0.66-0.78），经调整的relPHE的AUC为0.81（95％CI 0.76-0.87）。截断值在两个队列中均相同，relPHE为>0.70，经调整的relPHE为>0.01。在外部患者队列中，relPHE和经调整的relPHE能够准确区分CT成像中的新生物性和非新生物性ICH。结果证实了初始研究的发现，可能会改善临床决策。本文章受版权保护，版权所有。

Neoplastic intracerebral hemorrhage (ICH) may incorrectly indicate a non-neoplastic ICH on imaging. Relative perihematomal edema (relPHE) on Computed Tomography (CT) has been proposed as a marker to discriminate neoplastic from non-neoplastic ICH but has not been externally validated. The purpose of this study was to evaluate the discriminatory power of relPHE in an independent cohort.291 patients with acute ICH on CT and follow-up MRI were included in this single center retrospective study. ICH subjects were dichotomized into non-neoplastic or neoplastic ICH based on the diagnosis on the follow-up MRI. ICH-, PHE volumes and density values were derived from semi-manually segmented CT scans. Calculated PHE characteristics for discriminating neoplastic ICH were evaluated by receiver operating characteristics (ROC) curves. ROC curve associated cut-offs were calculated and compared between the initial and the validation cohort.116 (39.86%) patients with neoplastic ICH and 175 (60.14%) with non- neoplastic ICH were included. Median PHE volumes, relPHE, and relPHE adjusted for hematoma density were significantly higher in subjects with neoplastic ICH, all p-values <0.001. ROC curves for relPHE had an area under the curve (AUC) of 0.72 (95%CI 0.66-0.78) and an AUC of 0.81 (95%CI 0.76-0.87) for adjusted relPHE. Cut-offs were identical in both cohorts with > 0.70 for relPHE and > 0.01 for adjusted relPHE.RelPHE and adjusted relPHE accurately discriminated neoplastic from non-neoplastic ICH on CT imaging in an external patient cohort. Results confirmed the findings of the initial study and may improve clinical decision-making.This article is protected by copyright. All rights reserved.