Imaging of acute pulmonary embolism using a dual energy CT system with rapid kVp switching: Initial results

Abstract Purpose Computed tomography pulmonary angiography (CTPA) is considered as clinical gold standard for diagnosing pulmonary embolism (PE). Whereas conventional CTPA only offers anatomic information, dual energy CT (DECT) provides functional information on blood volume as surrogate of perfusio...

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Published in:European journal of radiology 2012-12, Vol.81 (12), p.3711-3718
Main Authors: Geyer, Lucas L, Scherr, Michael, Körner, Markus, Wirth, Stefan, Deak, Paul, Reiser, Maximilian F, Linsenmaier, Ulrich
Format: Article
Language:English
Subjects:
Acute Disease
Adult
Aged
Algorithms
Angiography - methods
Chest pain
Computed tomography
Dual energy
Female
Humans
Image Enhancement - methods
Lung perfusion
Male
Middle Aged
Observer Variation
Pulmonary embolism
Pulmonary Embolism - diagnostic imaging
Radiography, Dual-Energy Scanned Projection - methods
Radiology
Reproducibility of Results
Sensitivity and Specificity
Tomography, X-Ray Computed - methods
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Summary:Abstract Purpose Computed tomography pulmonary angiography (CTPA) is considered as clinical gold standard for diagnosing pulmonary embolism (PE). Whereas conventional CTPA only offers anatomic information, dual energy CT (DECT) provides functional information on blood volume as surrogate of perfusion by assessing the pulmonary iodine distribution. The purpose of this study was to evaluate the feasibility of lung perfusion imaging using a single-tube DECT scanner with rapid kVp switching. Materials and methods Fourteen patients with suspicion of acute PE underwent DECT. Two experienced radiologists assessed the CTPA images and lung perfusion maps regarding the presence of PE. The image quality was rated using a semi-quantitative 5-point scale: 1 (=excellent) to 5 (=non-diagnostic). Iodine concentrations were quantified by a ROI analysis. Results Seventy perfusion defects were identified in 266 lung segments: 13 (19%) were rated as consistent with PE. Five patients had signs of PE at CTPA. All patients with occlusive clots were correctly identified by DECT perfusion maps. On a per patient basis the sensitivity and specificity were 80.0% and 88.9%, respectively, while on a per segment basis it was 40.0% and 97.6%, respectively. None of the patients with a homogeneous perfusion map had an abnormal CTPA. The overall image quality of the perfusion maps was rated with a mean score of 2.6 ± 0.6. There was a significant ventrodorsal gradient of the median iodine concentrations (1.1 mg/cm3 vs. 1.7 mg/cm3 ). Conclusion Lung perfusion imaging on a DE CT-system with fast kVp-switching is feasible. DECT might be a helpful adjunct to assess the clinical severity of PE.
ISSN:0720-048X
1872-7727
DOI:10.1016/j.ejrad.2011.02.043