Objective: Staging of bronchiolitis obliterans syndrome (BOS) following lung transplantation is based on declines in forced expiratory volume in 1 s (FEV1). The aim of this study was to evaluate the usefulness of 133Xe ventilation scintigraphy in the early detection of BOS following living-donor lobar lung transplantation (LDLLT), to compare 133Xe washout imaging with computed tomography (CT) findings for early detection of BOS following LDLLT, and to evaluate 133Xe washout imaging by quantitative analyses. Methods: Subjects comprised 30 double-lung recipients and 1 single-lung recipient, who had undergone LDLLT at our institution and survived more than 1 year. Clinically diagnosed BOS developed in six recipients. Declines in graft function were evaluated using a combination of three methods, namely, dynamic spirometry, high-resolution CT (HRCT), and 133Xe ventilation scintigraphy. Findings for all transplanted lungs were compared between CT and 133Xe washout imaging. 133Xe washout imaging was assessed using mean transit time (MTT) of bi-and unilateral lungs. Correlations between MTT of bilateral lungs and FEV1% were evaluated. Differences in MTT between BOS and non-BOS lungs, and between non-BOS and donor lungs were also evaluated on unilateral lungs. Appropriate cut-off values of MTT of unilateral lungs were set for the diagnosis of BOS. Results: In all six BOS cases, prolonged-washout images of engrafted lungs revealed early-phase BOS with declines from baseline FEV1, whereas only one BOS case could be detected using early CT findings of BO (bronchodilatation, decrease in number and size of pulmonary vessels, thickening of septal lines, and volume reduction). A significant correlation was identified between MTT and FEV1% (r = -0.346, P <0.0001). MTT of unilateral lungs was significantly longer in BOS lungs than in non-BOS lungs (P <0.0001). The cut-off MTT of unilateral lungs for the diagnosis of BOS was set at 64.77 s. Conclusions: Our data show that 133Xe washout imaging offers excellent potential for early detection of BOS compared with early CT findings. Using 133Xe washout imaging and MTT with radioactive tracer offers a noninvasive indication of selective ventilatory function in engrafted lungs following LDLLT. MTT appears useful for identifying BOS following LDLLT and allows quantitative evaluation of graft function in unilateral lungs.
- Xe scintigraphy
- Bronchiolitis obliterans syndrome (BOS)
- Living-donor lobar lung transplantation (LDLLT)
- Mean transit time (MTT)
- Prolonged-washout images
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging