Department of Radiology, The Alfred Hospital, Victoria, Australia.
Department of Radiology, The Alfred Hospital, Victoria, Australia; Department of Surgery, Monash University, Victoria, Australia; Department of Neuroscience, Monash University, Victoria, Australia.
J Med Imaging Radiat Sci. 2020 Sep;51(3):451-461. doi: 10.1016/j.jmir.2020.06.002. Epub 2020 Jun 30.
Computed tomography pulmonary angiogram (CTPA) is widely considered the gold standard for diagnosis of pulmonary embolism (PE) with previous studies demonstrating high sensitivity and specificity. Despite this, nondiagnostic and indeterminate CTPA rates of 5%-26% remain a concern. As part of a continuing quality assurance program, a new weight-adjusted contrast dose and increased administration rate CTPA protocol was studied with an aim to improve diagnostic accuracy of PE evaluation.
A total of 2,398 CTPA examinations were reviewed to assess pulmonary arterial enhancement and PE yield in this retrospective study. Between 1 August 2014 and 1 August 2015, 1,133 patients received a fixed-volume (60 mL) contrast dose technique at 4 mL/s (protocol A). A new protocol was then implemented as part of a continuing quality assurance program. Between 15 September 2015 and 15 September 2016, 1,265 patients received a weight-adjusted contrast dose (1 mL/kg) and increased administration rate (5 mL/s) CTPA technique (protocol B). Studies were classed into categories based on quality of study; diagnostic: HU > 211, nondiagnostic: HU < 211 and PE yield; positive, negative, and indeterminate. These variables were compared with cross-sectional surface area to assess the relationship between patient habitus, CTPA diagnostic quality, and PE yield.
A weight-adjusted contrast dose and increased administration rate CTPA protocol (protocol B) resulted in a significant increase in mean PA enhancement (P < .0001), 55.23% decrease in nondiagnostic studies and 43.04% decrease in indeterminate studies. Protocol B demonstrated increased positive and negative CTPA rates with decreased indeterminate rates from 12.38% to 7.04%. Comparison with cross-sectional area demonstrated significant increase in proportion of diagnostic studies and reduction in nondiagnostic and indeterminate CTPAs using protocol B in obese patients.
A weight-adjusted contrast dose and increased administration rate CTPA protocol can significantly increase PA enhancement, especially in obese patients, resulting in greater high-quality and fewer nondiagnostic and indeterminate CTPA examinations. A CTPA protocol with a higher rate of conclusive examinations can provide greater confidence in PE evaluation for reporting radiologists and accurate clinical decision-making pathways for referring physicians.
计算机断层肺动脉造影（CTPA）被广泛认为是诊断肺栓塞（PE）的金标准，先前的研究表明其具有很高的灵敏度和特异性。尽管如此，5%-26%的非诊断性和不确定的 CTPA 率仍然令人担忧。作为持续质量保证计划的一部分，研究了一种新的体重调整对比剂量和增加给药速率 CTPA 方案，旨在提高 PE 评估的诊断准确性。
在这项回顾性研究中，共评估了 2398 例 CTPA 检查，以评估肺动脉增强和 PE 检出率。2014 年 8 月 1 日至 2015 年 8 月 1 日，1133 例患者接受了固定容量（60 毫升）对比剂量技术，给药速率为 4 毫升/秒（方案 A）。然后，作为持续质量保证计划的一部分，实施了一项新方案。2015 年 9 月 15 日至 2016 年 9 月 15 日，1265 例患者接受了体重调整对比剂量（1 毫升/公斤）和增加给药速率（5 毫升/秒）CTPA 技术（方案 B）。根据研究质量将研究分为类别；诊断：HU > 211，非诊断：HU < 211 和 PE 检出率；阳性、阴性和不确定。这些变量与横截面积进行了比较，以评估患者体型、CTPA 诊断质量和 PE 检出率之间的关系。
体重调整对比剂量和增加给药速率 CTPA 方案（方案 B）可显著提高平均 PA 增强（P <.0001），非诊断性研究减少 55.23%，不确定研究减少 43.04%。方案 B 显示阳性和阴性 CTPA 率增加，不确定率从 12.38%降至 7.04%。与横截面积的比较表明，在肥胖患者中，使用方案 B 可显著增加诊断性研究的比例，并减少非诊断性和不确定的 CTPA。
体重调整对比剂量和增加给药速率 CTPA 方案可显著提高 PA 增强，特别是在肥胖患者中，从而提高高质量和减少非诊断性和不确定的 CTPA 检查。具有更高结论性检查率的 CTPA 方案可为报告放射科医生提供更大的信心，并为转诊医生提供准确的临床决策途径。
