Pulmonary Perfused Blood Volume with Dual-Energy CT as Surrogate for Pulmonary Perfusion Assessed with Dynamic Multidetector CT

Fuld, Matthew K.; Halaweish, Ahmed F.; Haynes, Sue; Divekar, Abhay; Guo, Junfeng; Hoffman, Eric A.

doi:10.1148/radiol.12112789

Cited by 133 publications

(122 citation statements)

References 19 publications

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“…The average HU enhancement of 34 HU in this study is similar to the work of Groell et al , which observed an enhancement of 30 HU in the normal lung segment by comparing precontrast and postcontrast CT scans 37 . Also the 13–20 s delay time between contrast administration and CT image acquisition in this study is similar to other CT perfusion studies, e.g., 13 s by Wildberger et al 12 and 15 s by Fuld et al , 38 Given that this study included dogs with varying breeds (e.g., Pembroke Welsh Corgi and Shepherd), weight (range 13.1–42.5 kg), and lung pathologies (normal, primary lung tumor, lung metastasis, or interstitial lung disease), there might be intersubject variability in the hemodynamic profile, which could influence the optimal delay time. Optimizing the delay time using a more specific patient population would be an important subject of future work.…”

Section: Discussionsupporting

confidence: 90%

Single‐energy computed tomography‐based pulmonary perfusion imaging: Proof‐of‐principle in a canine model

et al. 2016

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Purpose:Radiotherapy (RT) that selectively avoids irradiating highly functional lung regions may reduce pulmonary toxicity, which is substantial in lung cancer RT. Single-energy computed tomography (CT) pulmonary perfusion imaging has several advantages (e.g., higher resolution) over other modalities and has great potential for widespread clinical implementation, particularly in RT. The purpose of this study was to establish proof-of-principle for single-energy CT perfusion imaging.Methods:Single-energy CT perfusion imaging is based on the following: (1) acquisition of end-inspiratory breath-hold CT scans before and after intravenous injection of iodinated contrast agents, (2) deformable image registration (DIR) for spatial mapping of those two CT image data sets, and (3) subtraction of the precontrast image data set from the postcontrast image data set, yielding a map of regional Hounsfield unit (HU) enhancement, a surrogate for regional perfusion. In a protocol approved by the institutional animal care and use committee, the authors acquired CT scans in the prone position for a total of 14 anesthetized canines (seven canines with normal lungs and seven canines with diseased lungs). The elastix algorithm was used for DIR. The accuracy of DIR was evaluated based on the target registration error (TRE) of 50 anatomic pulmonary landmarks per subject for 10 randomly selected subjects as well as on singularities (i.e., regions where the displacement vector field is not bijective). Prior to perfusion computation, HUs of the precontrast end-inspiratory image were corrected for variation in the lung inflation level between the precontrast and postcontrast end-inspiratory CT scans, using a model built from two additional precontrast CT scans at end-expiration and midinspiration. The authors also assessed spatial heterogeneity and gravitationally directed gradients of regional perfusion for normal lung subjects and diseased lung subjects using a two-sample two-tailed t-test.Results:The mean TRE (and standard deviation) was 0.6 ± 0.7 mm (smaller than the voxel dimension) for DIR between pre contrast and postcontrast end-inspiratory CT image data sets. No singularities were observed in the displacement vector fields. The mean HU enhancement (and standard deviation) was 37.3 ± 10.5 HU for normal lung subjects and 30.7 ± 13.5 HU for diseased lung subjects. Spatial heterogeneity of regional perfusion was found to be higher for diseased lung subjects than for normal lung subjects, i.e., a mean coefficient of variation of 2.06 vs 1.59 (p = 0.07). The average gravitationally directed gradient was strong and significant (R2 = 0.99, p < 0.01) for normal lung dogs, whereas it was moderate and nonsignificant (R2 = 0.61, p = 0.12) for diseased lung dogs.Conclusions:This canine study demonstrated the accuracy of DIR with subvoxel TREs on average, higher spatial heterogeneity of regional perfusion for diseased lung subjects than for normal lung subjects, and a strong gravitationally directed gradient for normal lung subjects, providing p...

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Section: Discussionsupporting

confidence: 90%

Single‐energy computed tomography‐based pulmonary perfusion imaging: Proof‐of‐principle in a canine model

et al. 2016

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“…Whether this phenomenon exists in patients with ALI remains speculative, but it was previously observed in healthy people during exercise (33). Interestingly, the same excellent correlation (R 2 5 0.84) between blood flow and blood volume was recently found in anesthetized, mechanically ventilated pigs (34). A weaker, although significant, correlation between lung perfusion and pulmonary blood volume (R 2 5 0.50) assessed with MR imaging was also found in 23 patients (35).…”

Section: Discussionmentioning

confidence: 53%

Noninvasive Quantitative Assessment of Pulmonary Blood Flow with ¹⁸F-FDG PET

et al. 2013

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Pulmonary blood flow (PBF) is a critical determinant of oxygenation during acute lung injury (ALI). PET/CT with 18 F-FDG allows the assessment of both lung aeration and neutrophil inflammation as well as an estimation of the regional fraction of blood (FB) if compartmental modeling is used to quantify 18 F-FDG pulmonary uptake. The aim of this study was to validate the use of FB to assess PBF, with PET and compartmental modeling of 15 O-H 2 O kinetics as a reference method, in both control animals and animals with ALI. For the purpose of studying a wide range of PBF values, supine and prone positions and various positive end-expiratory pressures (PEEPs) and tidal volumes (V T s) were selected. Methods: Pigs were randomized into 3 groups in which ALI was induced by HCl inhalation: pigs studied in the supine position with a low PEEP (5 6 3 [mean 6 SD] cm of H 2 O; n 5 9) or a high PEEP (12 6 1 cm of H 2 O; n 5 8) and pigs studied in the prone position with a low PEEP (6 6 3 cm of H 2 O; n 5 9). Also included were a control group that did not have ALI (n 5 6) and 2 additional groups (n 5 6 each) that had a high V T to maintain a transpulmonary pressure of greater than or equal to 35 cm of H 2 O and that either received HCl inhalation or did not receive HCl inhalation. PBF and FB were measured with PET and compartmental modeling of 15 O-H 2 O and 18 F-FDG kinetics in 10 lung regions along the anterior-to-posterior lung dimension, and both were expressed in each region as a fraction of their values in the whole lung. Results: PBF and FB were strongly correlated (R 2 5 0.9), with a slope of the regression line close to unity and a negligible intercept. The mean difference between PBF and FB was 0, and the 95% limits of agreement were 20.035 to 0.035. This good agreement between methods was obtained in both normal and injured lungs and under a wide range of V T , PEEP, and regional PBF values (7-71 mL/kg, 0-15 cm of H 2 O, and 24-603 mLÁ min 21 Á100 mL of lung 21 , respectively). Conclusion: FB assessed with 18 F-FDG is a good surrogate for PBF in both normal animals and animals with ALI. PET/CT has the potential to be used to study ventilation, perfusion, and lung inflammation with a single tracer.

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“…Noteworthy, the r value and slope obtained in this study are comparable to those calculated by Schuster et al [6] ( r = 0.77, slope = 0.92) and Richard et al [9] ( r = 0.79, slope = 0.79) using PET and 15 O-labeled water. Unfortunately, there is no PBF obtained by CT to compare with our results [26, 27]. …”

Section: Discussionmentioning

confidence: 79%

“…This is even more important due to the fact that these agents, either linear or macrocyclic, are under investigation for multiple results demonstrating their potential accumulation in various tissues regardless of renal function [25]. Our alternative has a simpler implementation and provides quantitative measures of the regional blood flow compared to recent approaches using dual energy CT imaging [26, 27]. Compared to other PET-based alternatives such as 15 O-water [7] or dissolved 13 N 2 [28] that need an on-site cyclotron, our solution could be potentially more widely available due to the introduction of gallium generators in the field and the approval of different gallium-chelated agents for human use.…”

Section: Discussionmentioning

confidence: 99%

Assessment of regional pulmonary blood flow using 68Ga-DOTA PET

et al. 2017

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BackgroundIn vivo determination of regional pulmonary blood flow (PBF) is a valuable tool for the evaluation of many lung diseases. In this study, the use of 68Ga-DOTA PET for the in vivo quantitative determination of regional PBF is proposed. This methodology was implemented and tested in healthy pigs and validated using fluorescent microspheres. The study was performed on young large white pigs (n = 4). To assess the reproducibility and consistency of the method, three PET scans were obtained for each animal. Each radiotracer injection was performed simultaneously to the injection of fluorescent microspheres. PBF images were generated applying a two-compartment exchange model over the dynamic PET images. PET and microspheres values were compared by regression analysis and Bland–Altman plot.ResultsThe capability of the proposed technique to produce 3D regional PBF images was demonstrated. The correlation evaluation between 68Ga-DOTA PET and microspheres showed a good and significant correlation (r = 0.74, P < 0.001).ConclusionsAssessment of PBF with the proposed technique allows combining the high quantitative accuracy of PET imaging with the use of 68Ga/68Ge generators. Thus, 68Ga-DOTA PET emerges as a potential inexpensive method for measuring PBF in clinical settings with an extended use.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-017-0259-2) contains supplementary material, which is available to authorized users.

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Pulmonary Perfused Blood Volume with Dual-Energy CT as Surrogate for Pulmonary Perfusion Assessed with Dynamic Multidetector CT

Abstract: CT-derived PBV heterogeneity is a suitable surrogate for CT-derived PBF heterogeneity.

Cited by 133 publications

References 19 publications

Single‐energy computed tomography‐based pulmonary perfusion imaging: Proof‐of‐principle in a canine model

Single‐energy computed tomography‐based pulmonary perfusion imaging: Proof‐of‐principle in a canine model

Noninvasive Quantitative Assessment of Pulmonary Blood Flow with ¹⁸F-FDG PET

Assessment of regional pulmonary blood flow using 68Ga-DOTA PET

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Pulmonary Perfused Blood Volume with Dual-Energy CT as Surrogate for Pulmonary Perfusion Assessed with Dynamic Multidetector CT

Abstract: CT-derived PBV heterogeneity is a suitable surrogate for CT-derived PBF heterogeneity.

Cited by 133 publications

References 19 publications

Single‐energy computed tomography‐based pulmonary perfusion imaging: Proof‐of‐principle in a canine model

Single‐energy computed tomography‐based pulmonary perfusion imaging: Proof‐of‐principle in a canine model

Noninvasive Quantitative Assessment of Pulmonary Blood Flow with 18F-FDG PET

Assessment of regional pulmonary blood flow using 68Ga-DOTA PET

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Noninvasive Quantitative Assessment of Pulmonary Blood Flow with ¹⁸F-FDG PET