Wu Dan, Wang Gang, Bian Bingyang, Liu Zhuohang, Li Dan
Department of Radiology, The First Hospital of Jilin University, Changchun, Jilin, People's Republic of China.
Department of Orthopedics, The Third Hospital of Jilin University, Changchun, Jilin, People's Republic of China.
Dose Response. 2020 Mar 6;19(1):1559325820909778. doi: 10.1177/1559325820909778. eCollection 2020 Jan-Mar.
For patients with intracranial hemorrhage (ICH), routine follow-up computed tomography (CT) scans are typically required to monitor the progression of intracranial pathology. Remarkable levels of radiation exposure are accumulated during repeated CT scan. However, the effects and associated risks have still remained elusive. This study presented an effective approach to quantify organ-specific radiation dose of repeated CT scans of head for patients with ICH. We also indicated whether a low-dose CT scan may reduce radiation exposure and keep the image quality highly acceptable for diagnosis.
Herein, 72 patients with a history of ICH were recruited. The patients were divided into 4 groups and underwent CT scan of head with different tube current-time products (250, 200, 150, and 100 mAs). Two experienced radiologists visually rated scores of quality of images according to objective image noise, sharpness, diagnostic acceptability, and artifacts due to physiological noise on the same workstation. Organ-/tissue-specific radiation doses were analyzed using Radimetrics.
In conventional CT scan group, signal to noise ratio (SNR) and contrast to noise ratio (CNR) of ICH images were significantly higher than those in normal brain structures. Reducing the tube current-time product may decrease the image quality. However, the predilection sites for ICH could be clearly identified. The SNR and CNR in the predilection sites for ICH were notably higher than other areas. The brain, eye lenses, and salivary glands received the highest radiation dose. Reducing tube current-time product from 250 to 100 mA can significantly reduce the radiation dose.
We demonstrated that low-dose CT scan of head can still provide reasonable images for diagnosing ICH. The radiation dose can be reduced to ∼45% of the conventional CT scan group.
对于颅内出血（ICH）患者，通常需要进行常规的随访计算机断层扫描（CT）以监测颅内病变的进展。在重复进行CT扫描期间会累积相当高的辐射暴露量。然而，其影响和相关风险仍不明确。本研究提出了一种有效方法来量化ICH患者头部重复CT扫描的器官特异性辐射剂量。我们还指出低剂量CT扫描是否可以减少辐射暴露并使图像质量在诊断上高度可接受。
在此，招募了72例有ICH病史的患者。将患者分为4组，并使用不同的管电流 - 时间乘积（250、200、150和100 mAs）进行头部CT扫描。两名经验丰富的放射科医生在同一工作站上根据客观图像噪声、清晰度、诊断可接受性以及生理噪声引起的伪影对图像质量进行视觉评分。使用Radimetrics分析器官/组织特异性辐射剂量。
在常规CT扫描组中，ICH图像的信噪比（SNR）和对比噪声比（CNR）显著高于正常脑结构中的图像。降低管电流 - 时间乘积可能会降低图像质量。然而，ICH的好发部位仍可清晰识别。ICH好发部位的SNR和CNR明显高于其他区域。大脑、晶状体和唾液腺接受的辐射剂量最高。将管电流 - 时间乘积从250 mAs降低到100 mAs可显著降低辐射剂量。
我们证明头部低剂量CT扫描仍可为诊断ICH提供合理的图像。辐射剂量可降低至常规CT扫描组的约45％。
