Department of Diagnostic Imaging, Evidensia Södra Djursjukhuset, Månskärsvägen 13, Kungens Kurva, 141 75, Stockholm, Sweden.
Acta Vet Scand. 2022 Sep 8;64(1):25. doi: 10.1186/s13028-022-00643-0.
Computed tomography (CT) scanning of the lung is known to be a valuable tool when investigating lung pathology of the dog. During CT-scan the dog needs to be immobilized and general anesthesia has historically been considered as gold standard although being a more expensive and time-consuming alternative to sedation. Today, modern high speed multidetector CT-scanners offer new possibilities for sedation as an alternative. Both anesthesia and sedation can cause lung atelectasis, and this can be problematic when reading the CT-images since it potentially can masque or mimic lung pathology leading to misdiagnosis. The objective of this prospective analytic study was to investigate the prevalence of lung atelectasis and changes in lung attenuation over time in dogs that receive intravenous sedation and positioned in sternal recumbency.
20 dogs without known lung pathology underwent three consecutive CT-scans of the lung; the first scan was initiated as soon as the dog was sufficiently sedated, the second scan approximately 5 min after the first one and the last scan after the dog's orthopaedic scan was completed. The dogs received intravenous sedation in a combination of dexmedetomidine and butorphanol and were kept positioned in a strict sternal recumbency during sedation and exam. Each lung lobe was individually examined in an axial plane and measurements of dorsal, ventral, and mean lung attenuation were made. Atelectasis or areas with poorly aerated lung tissue were not detected as all parts of the lobes were normally aerated at all three scans. A statistically significant increase in lung attenuation between the first and the second scan (P = 0.03) and between the first and the third scan (P = 0.0004) was seen in the ventral part of the lobes.
This study indicates that CT-examination of the lungs can be performed on sedated dogs that are kept in a sternal recumbency without development of atelectasis. It also suggests that there is an early correlation between time and increase in lung attenuation.
计算机断层扫描（CT）是一种有价值的工具，可用于研究犬的肺部病理学。在 CT 扫描过程中，狗需要保持不动，而全身麻醉一直被认为是金标准，尽管它比镇静更昂贵且耗时。如今，现代高速多排 CT 扫描仪为镇静提供了新的替代方案。麻醉和镇静都可能导致肺不张，这在阅读 CT 图像时会产生问题，因为它可能会掩盖或模拟肺部病理学，导致误诊。本前瞻性分析研究的目的是调查接受静脉镇静并处于胸骨卧位的狗的肺不张发生率和肺衰减随时间的变化。
20 只无已知肺部疾病的狗接受了三次连续的肺部 CT 扫描；第一次扫描是在狗充分镇静后立即开始的，第二次扫描大约在第一次扫描后 5 分钟进行，最后一次扫描是在狗的骨科扫描完成后进行的。狗接受了右美托咪定和布托啡诺的静脉镇静，并在镇静和检查期间保持严格的胸骨卧位。每个肺叶在轴位平面上单独检查，并测量背侧、腹侧和平均肺衰减。由于所有叶段在三次扫描中都正常充气，因此未检测到肺不张或充气不良的肺组织区域。在叶段的腹侧部分，第一次和第二次扫描（P=0.03）以及第一次和第三次扫描（P=0.0004）之间的肺衰减值均呈统计学显著增加。
本研究表明，在保持胸骨卧位的镇静犬中可以进行肺部 CT 检查，而不会发生肺不张。这也表明，时间和肺衰减之间存在早期相关性。
