This study aimed to evaluate the reproducibility of functional lung imaging derived from two CT-based modalities: dual-energy CT (DECT) perfusion blood volume (PBV) maps and four-dimensional CT (4DCT) ventilation imaging. The investigators framed the work in the context of functional lung assessment for patients undergoing definitive treatment for locally advanced non-small cell lung cancer (NSCLC). Reproducible imaging biomarkers for perfusion and ventilation are important when considering image-guided treatment adaptation, toxicity risk assessment, or longitudinal monitoring of lung function during and after radiotherapy (RT).
Patients were enrolled on an institutional review board–approved clinical trial of functional lung imaging. All participants had locally advanced NSCLC and received definitive, conventionally fractionated concurrent chemoradiation therapy. Some patients also received consolidation immunotherapy; the abstract indicates inclusion both with and without consolidation immunotherapy but does not provide counts or proportions. No further demographic, staging, or comorbidity data were reported in the provided source excerpt.
Imaging was performed at three predefined timepoints for each participant:
At each timepoint the protocol included both free-breathing 4DCT to derive ventilation maps and contrast-enhanced DECT to derive perfusion blood volume (PBV) maps. Acquiring both modalities at multiple timepoints enables assessment of short-term reproducibility (between baseline and early treatment) and longer-term changes (at six months), though the reproducibility analysis reported in the abstract focused on the first two timepoints.
The abstract explicitly states that scans were free-breathing 4DCT and contrast-enhanced DECT acquired at each scheduled timepoint. Beyond modality names and the use of contrast for DECT, the provided excerpt does not report acquisition parameters such as DECT energy settings, contrast volume and timing, 4DCT phase binning, slice thickness, scanner models, or patient positioning and immobilization details. The excerpt also does not detail whether breath coaching, gating, or motion-correction strategies were used during acquisition or postprocessing.
To evaluate reproducibility of PBV and ventilation maps, the investigators planned to compare voxel intensities within the lung parenchyma between the first two timepoints (RT simulation and second week of RT). The abstract indicates a voxel-level approach restricted to lung parenchyma, implying that images were segmented to exclude non-parenchymal tissues prior to analysis. The excerpt does not provide further methodological specifics such as:
Because the source abstract text provided is truncated, these key analytic and processing details were not reported in the excerpt.
The supplied PubMed/NCBI excerpt ends partway through the methods description and does not include results, quantitative reproducibility measures, statistical analyses, or study conclusions. Specifically, numeric outcomes, measures of agreement, thresholds of acceptable reproducibility, and any clinical interpretations or recommendations are not present in the provided text.
Readers seeking the study results, full methods, and authors’ conclusions should consult the full published article (Phys Med Biol, doi: 10.1088/1361-6560/aea51b). The PubMed abstract excerpt available here does not report the reproducibility findings or the methodological granularity required to assess the robustness of the reproducibility analysis.
From the design reported in the abstract excerpt, the study addresses an important clinical question: whether DECT-derived PBV and 4DCT-derived ventilation maps are reproducible early in treatment, which is a prerequisite for their use in adaptive RT planning or functional avoidance strategies. However, because outcome data and processing details are not included in the provided source, no conclusions about the reproducibility, reliability, or clinical utility of the reported imaging biomarkers can be drawn from this excerpt alone.
If you need a summary of the reported results, reproducibility metrics, or the image-processing pipeline, please provide the full abstract or full-text content. Those sections were not present in the source material supplied here and therefore could not be summarized or paraphrased.