橋本 直純

BACKGROUND: We compared the capabilities of quantitatively assessed paired inspiratory-expiratory area-detector computed tomography (ADCT) for pulmonary functional loss and disease severity evaluations between upright and supine ADCT in matched progressive pulmonary fibrosis (PPF) patients. MATERIALS AND METHODS: This retrospective cohort consisted of age-, sex-, and underlying disease-matched patients with PPF who underwent paired inspiratory-expiratory CT on upright ADCT (n = 40) and supine ADCT (n = 40), pulmonary function tests, and disease severity assessment. Based on CT data, the absolute values of the logarithm of the Jacobian determinant and warp-field magnitude of the whole lung and all lobes were calculated. Stepwise regression analyses were performed. RESULTS: On supine ADCT, both indices of the left lower lobe (LLL) were the first and only steps for pulmonary function test results and CT-assessed disease severity (absolute value of the logarithm of the Jacobian determinant: 0.139 ≤ r2 ≤ 0.175, 0.007 ≤ p ≤ 0.018; absolute value of the warp-field magnitude: 0.371 ≤ r2 ≤ 0.447, p < 0.001). However, on upright ADCT, both indices indicated that LLL was the first step and the right lower lobe was the second step for pulmonary function test results and CT-assessed disease severity (0.503 ≤ r2 ≤ 0.674, p < 0.001 or 0.000 < p ≤ 0.006 and 0.474 ≤ r2 ≤ 0.652, 0.002 ≤ p ≤ 0.045, respectively). CONCLUSION: Upright ADCT has equal to or better potential than supine ADCT for detecting pulmonary functional loss and evaluating disease severity when paired inspiratory-expiratory ADCT is applied in PPF patients. RELEVANCE STATEMENT: Upright ADCT has superior potential to supine ADCT for pulmonary functional loss and disease severity evaluations when paired inspiratory-expiratory ADCT is performed in patients with progressive pulmonary fibrosis (PPF). KEY POINTS: Matched progressive pulmonary fibrosis patients compared functional loss and disease severity evaluations between inspiratory-expiratory upright and supine area-detector CT. Clinical parameters demonstrated better correlations with upright than with supine inspiratory-expiratory area-detector CT. Warp-field magnitude showed better correlations with disease severities than the logarithm of the Jacobian determinant on each area-detector CT.

Introduction: Accurate diagnosis of peripheral pulmonary lesions is crucial in respiratory medicine. Radial endobronchial ultrasound (R-EBUS), navigation technologies, and ultrathin bronchoscopes have progressively enhanced distal airway access. Mixed reality (MR) offers a hands-free method for visualizing and manipulating CT-derived three-dimensional (3D) anatomy within the operator’s field of view. This retrospective study aimed to describe the technical feasibility and safety of intraprocedural MR-based holographic virtual bronchoscopy (VB) use. Methods: This study included patients who underwent bronchoscopy for peripheral pulmonary lesions using an MR-based 3D holographic VB system. CT datasets were converted into 3D polygon models and displayed on a HoloLens 2 headset. Operators/assistants intraprocedurally referenced and manipulated the hologram while advancing the bronchoscope. Procedural variables, R-EBUS findings, biopsy techniques, diagnostic yield, and complications were evaluated. Results: Eighteen patients were included. A direct bronchus sign was present in 12 lesions. The median bronchial generation that could be visualized on CT and 3D-VB was six, whereas bronchoscopy enabled advancement to a median of five generations. Radial EBUS demonstrated a within-lesion position in 13 cases. Biopsy techniques included forceps biopsy, cryobiopsy, and TBNA. The overall diagnostic yield was 72.2% (13/18), with malignant disease accounting for the majority of diagnoses. One patient developed mild pneumothorax, which resolved without drainage. Conclusion: MR-based holographic VB enabled real-time, hands-free 3D anatomical referencing without interrupting the procedure. Further prospective studies are warranted to assess procedural benefits and potential integration with other bronchoscopic modalities and devices.