Yoshiyuki Ozawa

Chest CT has become a key component of the diagnostic approach to a wide range of airway and vascular diseases, including asthma, emphysema, chronic airways disease, and pulmonary vascular disorders such as pulmonary embolism. The interaction between ventilation and perfusion is complex but is always aimed at optimal matching to enable efficient gas exchange. If either one or both of these are affected by disease, they have a negative effect on the other. CT is able to define the structure of lung parenchyma, airways, and pulmonary vasculature in great detail. Beyond morphology, increasingly sophisticated scanner and software technology increase the diagnostic scope of CT toward obtaining comprehensive functional information. This paves the way for new understanding of lung function, the effects of various diseases, and the way in which therapeutic interventions have an effect. Greater understanding of the principal components of chest CT and how they are developing into clinical practice is relevant to anyone with an interest in diagnostic chest imaging. Keywords: CT-Spectral Imaging (Dual Energy), Applications-CT, CT-Quantitative, CT-Perfusion, Thorax, Lung © RSNA, 2025.

Background: When considering the effects of dupilumab on severe chronic rhinosinusitis with nasal polyps (CRSwNPs), dupilumab is expected to achieve CRSwNPs remission. The aim of this study was to assess the rate of remission of CRSwNPs with comorbid asthma and its predictors on a 24-month course of dupilumab. Methods: Adult patients with severe CRSwNPs and comorbid asthma who had completed a 24-month course of dupilumab were included in this post hoc analysis. The primary outcome was the rate of CRSwNPs remission at 12 and 24 months of dupilumab. The secondary outcome was to identify factors associated with CRSwNPs remission at 12 and 24 months. Based on the European criteria and a previous definition, remission was defined as the absence of symptoms, improved quality of life, no need for surgery, no exacerbations, recovery of olfactory function, and inactive disease by nasal endoscopy for ≥12 months. A rigorous six-component remission, including olfactory testing, was initially used. Results: Of 16 patients, 4 (25%) and 5 (31%) achieved six-component remission of CRSwNPs at 12 and 24 months, respectively. Patients with shorter disease duration and better olfactory function at baseline achieved six-component remission of CRSwNPs more frequently than those without at 24 months (both p < 0.05). Conclusions: Remission of severe CRSwNPs with comorbid asthma is attainable with a 24-month course of dupilumab.

OBJECTIVES: To determine the capability of dynamic contrast-enhanced (CE-) perfusion area-detector CT (ADCT) for detecting pathological structural changes in stage I non-small cell lung cancer (NSCLC) patients. MATERIALS AND METHODS: Sixty-three consecutive stage I NSCLC patients with progressive fibrosing interstitial lung disease (PF-ILD) underwent dynamic CE-perfusion ADCT analyzed by dual-input maximum slope (DMS) methods for total, pulmonary arterial and systemic arterial perfusion (TPDMS, PAPDMS and SAPDMS) maps, surgical treatment and pathological examination. Multicentric ROIs were then placed over sites assessed as normal lung, pulmonary emphysema, GGO or reticular pattern without traction bronchiectasis, reticular pattern with traction bronchiectasis and honeycombing in the resected lung. Next, an analysis of variance (ANOVA) followed by Tukey's honest significant difference (HSD) multiple comparison test was performed for a comparison of each of the perfusion parameters for five groups. Finally, discrimination accuracy for evaluation of lung parenchymal change was compared for all indexes and combined methods. RESULTS: PAPDMSs of abnormal lungs were significantly lower than that of normal lungs (p < 0.0001). SAPDMSs of normal or emphysematous lungs were significantly lower than those of others (p < 0.0001). SAPDMS of GGO or reticular pattern without traction bronchiectasis was significantly lower than that for reticular pattern with traction bronchiectasis and honeycombing (p < 0.0001). Discrimination accuracy of combined perfusion index was significantly higher than that of each index (p < 0.0001). CONCLUSION: Dynamic CE-perfusion ADCT is useful for detecting pathological structural changes in stage I NSCLC patients with PF-ILD. KEY POINTS: Question Can dynamic first-pass contrast-enhanced perfusion matrices evaluate parenchymal lung changes and disease severity of parenchymal diseases in stage I non-small cell lung cancer (NSCLC) patients? Findings Perfusion indexes differentiated significantly among normal lung, emphysema, GGO or reticular pattern without traction bronchiectasis, reticular pattern with traction bronchiectasis and honeycombing and significantly improved discrimination accuracy by combined methods. Clinical relevance Dynamic first-pass contrast-enhanced perfusion area-detector CT has the potential to assess underlying pathologies and pulmonary functional changes in stage I non-small cell carcinoma patients with progressive fibrosing interstitial lung disease.

OBJECTIVE: To directly compare coronary arterial stenosis evaluations by hybrid-type iterative reconstruction (IR), model-based IR (MBIR), deep learning reconstruction (DLR), and high-resolution deep learning reconstruction (HR-DLR) on coronary computed tomography angiography (CCTA) in both in vitro and in vivo studies. MATERIALS AND METHODS: For the in vitro study, a total of three-vessel tube phantoms with diameters of 3 mm, 4 mm, and 5 mm and with simulated non-calcified stepped stenosis plaques with degrees of 0%, 25%, 50%, and 75% stenosis were scanned with area-detector CT (ADCT) and ultra-high-resolution CT (UHR-CT). Then, ADCT data were reconstructed using all methods, although UHR-CT data were reconstructed with hybrid-type IR, MBIR, and DLR. For the in vivo study, patients who had undergone CCTA at ADCT were retrospectively selected, and each CCTA data set was reconstructed with all methods. To compare the image noise and measurement accuracy at each of the stenosis levels, image noise, and inner diameter were evaluated and statistically compared. To determine the effect of HR-DLR on CAD-RADS evaluation accuracy, the accuracy of CAD-RADS categorization of all CCTAs was compared by using McNemar's test. RESULTS: The image noise of HR-DLR was significantly lower than that of others on ADCT and UHR-CT (p < 0.0001). At a 50% and 75% stenosis level for each phantom, hybrid-type IR showed a significantly larger mean difference on ADCT than did others (p < 0.05). At in vivo study, 31 patients were included. Accuracy on HR-DLR was significantly higher than that on hybrid-type IR, MBIR, or DLR (p < 0.0001). CONCLUSION: HR-DLR is potentially superior for coronary arterial stenosis evaluations to hybrid-type IR, MBIR, or DLR shown on CCTA. KEY POINTS: Question How do coronary arterial stenosis evaluations by hybrid-type IR, MBIR, DLR, and HR-DLR compare to coronary CT angiography? Findings HR-DLR showed significantly lower image noise and more accurate coronary artery disease reporting and data system (CAD-RADS) evaluation than others. Clinical relevance HR-DLR is potentially superior to other reconstruction methods for coronary arterial stenosis evaluations, as demonstrated by coronary CT angiography results on ADCT and as shown in both in vitro and in vivo studies.