Evaluation of the ΔV 4D CT ventilation calculation method usingin vivoxenon CT ventilation data and comparison to other methods

Abstract

Ventilation distribution calculation using 4D CT has shown promising potential in several clinical applications. This study evaluated the direct geometric ventilation calculation method, namely the ΔV method, with xenon‐enhanced CT (XeCT) ventilation data from four sheep, and compared it with two other published methods, the Jacobian and the Hounsfield unit (HU) methods. Spearman correlation coefficient (SCC) and Dice similarity coefficient (DSC) were used for the evaluation and comparison. The average SCC with one standard deviation was 0.44±0.13 with a range between 0.29 and 0.61 between the XeCT and DLV ventilation distributions. The average DSC value for lower 30% ventilation volumes between the XeCT and ΔV ventilation distributions was 0.55±0.07 with a range between 0.48 and 0.63. Ventilation difference introduced by deformable image registration errors improved with smoothing. In conclusion, ventilation distributions generated using ΔV‐4D CT and deformable image registration are in reasonably agreement with the in vivo XeCT measured ventilation distribution.PACS number(s): 87.57.N‐, 87.57.nj, 87.57.Q‐, 87.85.Pq

Evaluation of lung toxicity risk with computed tomography ventilation image for thoracic cancer patients

“…To compare the Xe-CT ventilation measurements to the Jacobian from the image registration transformation, for each animal we manually registered the Xe-CT slices to a 3D rectangular region in the 0 cm H2 O airway pressures image by using a rigid transformation to match major anatomic landmarks [ 14 ]. There are low correction with comparing CT ventilation and Xe-CT from sheep [ 15 ].…”

Ventilation Series Similarity: A Study for Ventilation Calculation Using Deformable Image Registration and 4DCT to Avoid Motion Artifacts

“…One of the advantages of this approach is its higher spatial resolution compared to nuclear medicine scans [ 6 ]. It has been shown that this technique agrees reasonably well with other methods, such as SPECT, Xenon-enhanced dynamic CT, and PET [ 7 – 10 ]. Although ventilation distribution by Xenon-enhanced dynamic CT can achieve similar resolution, because of the dynamic scanning, only a part of the lung can be covered in a ventilation scan, and the technique itself is more complicated compared to 4DCT [ 7 , 10 ].…”

“…It has been shown that this technique agrees reasonably well with other methods, such as SPECT, Xenon-enhanced dynamic CT, and PET [ 7 – 10 ]. Although ventilation distribution by Xenon-enhanced dynamic CT can achieve similar resolution, because of the dynamic scanning, only a part of the lung can be covered in a ventilation scan, and the technique itself is more complicated compared to 4DCT [ 7 , 10 ]. Since 4DCT is already widely used in thoracic cancer radiotherapy treatment planning, in principle, using the 4DCT/DIR technique, one could determine regions of high lung ventilation in thoracic cancer patients and attempt to spare them in radiotherapy treatment planning, without the need for an additional imaging procedure [ 11 ].…”

“…Errors in DIR caused by the image artifacts and noise will be reflected in the calculated ventilation distributions [ 16 ]. To reduce their influence, the calculated ventilation datasets were smoothed with a 9 × 9 × 9 mm 3 (or 9 × 9 × 3 voxels) average filter [ 10 ].…”

Spatial Comparison of CT-Based Surrogates of Lung Ventilation With Hyperpolarized Helium-3 and Xenon-129 Gas MRI in Patients Undergoing Radiation Therapy

“…Comparing CT ventilation-derived metrics such as defective lung volumes and coefficients of variation with global measurements of spirometry, moderate correlations between FEV 1 and FEV/FVC, ranging from 0.43 to 0.73 and 0.38 to 0.73 for the intensity and Jacobian metrics have been reported, respectively [6,54]. In animal experiments, CT-based ventilatory surrogates have demonstrated both a reasonably high level (Jacobian metric, linear regression = 0.73 [39]; intensity metric, correlation coefficient = 0.66 [15]; hybrid metric, correlation coefficient = 0.82, [13]) and relatively low level (geometric metric, Spearman coefficient = 0.44 [57]) of correlation with contrast enhanced Xenon-CT. However, the subjects were mechanically ventilated and the Xenon-CT used had limited axial coverage thus limiting its ability to provide a validation over the full lung volume.…”