Efficacy of Iodine Perfusion Maps from Dual-energy Computed Tomography of the Pulmonary Arteries in Pulmonary Embolism Assessment
SY Tan, K Lau, A Borsaru, D Jackson, D Nandurkar
Hong Kong J Radiol 2019;22:243-8
https://doi.org/10.12809/hkjr1916942
Introduction: There has been increasing availability and use of dual-energy computed tomography (DECT) over recent years. The aim of this study was to evaluate the sensitivity, specificity, and accuracy of iodine perfusion maps in diagnosing pulmonary embolus (PE) using a DECT scanner.
Methods: A retrospective study was performed comparing the detection of PE and correlation of PE types (central vs. segmental and occlusive vs. non-occlusive) on computed tomographic pulmonary angiography (CTPA) and iodine perfusion maps. Diagnostic performance parameters were calculated for each reader and for the different types of PE. Interobserver variability was measured for the two techniques.
Results: Both radiologists demonstrated consistent diagnostic performance in detecting PEs on CTPA. However, diagnostic performance varied widely in the detection of a defect on iodine perfusion maps. Iodine perfusion scans demonstrated a high sensitivity for occlusive and central PE but a low sensitivity for non-occlusive and segmental PE, whereas their specificity in the detection of central PE was similar to that of segmental PE. Positive predictive value (PPV) of iodine perfusion scans was higher for central PE than for segmental PE, whereas negative predictive value (NPV) was lower for segmental PE than for central PE. Occlusive PE had a low PPV and a high NPV, whereas non-occlusive PE had a lower PPV and NPV. Interobserver agreement was high in the interpretation of CTPA and fair in the interpretation of iodine perfusion maps.
Conclusion: Iodine perfusion maps should be read in conjunction with CTPA. A normal iodine perfusion map excludes a central or occlusive PE.
Author affiliation(s):
SY Tan, K Lau, A Borsaru, D Jackson, D Nandurkar: Diagnostic Imaging Department, Monash Health, Victoria, Australia
K Lau: Faculty of Medicine, Nursing and Health Sciences, Monash University, Australia
中文摘要
雙能電腦斷層掃描碘灌注圖評估肺栓塞肺動脈的效果
SY Tan、K Lau、A Borsaru、D Jackson、D Nandurkar
引言：近年，雙能電腦斷層掃描（DECT）的使用日益增加。本研究旨在評估使用DECT碘灌注圖對診斷肺栓塞的敏感性、特異性和準確性。
方法：回顧性研究比較電腦斷層掃描肺血管造影（CTPA）和CT碘灌注圖檢測肺栓塞和肺栓塞類型的相關性（中央型和節段型肺栓塞、閉塞型和非閉塞型肺栓塞）。為每位放射科醫生和不同類型肺栓塞計算診斷性能參數，以及記錄兩種技術的觀察者間差異。
結果：兩位放射科醫生通過CTPA診斷肺栓塞表現一致，但通過碘灌注圖診斷時卻有較大差異。碘灌注圖顯示對閉塞型和中央型肺栓塞敏感度高，但對非閉塞型和節段型肺栓塞敏感度低；診斷中央型肺栓塞的特異性與節段型肺栓塞相似。碘灌注圖掃描的陽性預測值（PPV）方面，中央型較節段型肺栓塞高，而節段型肺栓塞的陰性預測值（NPV）低於中央型肺栓塞。閉塞型肺栓塞的PPV較低而NPV較高，非閉塞肺栓塞的PPV和NPV則均低。觀察者對CTPA判斷有高度一致性，對碘灌注圖判斷的一致性一般。
結論：應結合碘灌注圖與CTPA進行分析。正常碘灌注圖可排除中央型或閉塞型肺栓塞。