Prediction of Ablation Volume in Percutaneous Lung Microwave Ablation: A Single Centre Retrospective Study

Background: Percutaneous Microwave Ablation (MWA) of lung malignancies is a procedure with many technical challenges, among them the risk of residual disease. Recently, dedicated software able to predict the volume of the ablated area was introduced. Cone-beam computed tomography (CBCT) is the imaging guidance of choice for pulmonary ablation in our institution. The volumetric prediction software (VPS) has been installed and used in combination with CBCT to check the correct position of the device. Our study aimed to compare the results of MWA of pulmonary tumours performed using CBCT with and without VPS. Methods: We retrospectively reviewed 1-month follow-up enhanced contrast-enhanced computed tomography (CECT) scans of 10 patients who underwent ablation with the assistance of VPS (group 1) and of 10 patients who were treated without the assistance of VPS (group 2). All patients were treated for curative purposes, the maximum axial diameter of lesions ranged between 5 and 22 mm in group 1 and between 5 and 25 mm in group 2. We compared the presence of residual disease between the two groups. Results: In group 1 residual disease was seen in only 1 patient (10%) in which VPS had ensured complete coverage of the tumour. In group 2 residual disease was found in 3 patients (30%). Conclusions: Using this software during MWA of lung malignancies could improve the efficacy of the treatment compared to the conventional only CBCT guidance

Regional analysis with quantitative computed tomography after lung transplantation

Regional analysis with quantitative computed tomography (CT) of graft could be an attractive technique to interpret lung patterns after transplantation. Aim of this study was the definition of lung regional patterns in the early post-transplantation period. We prospectively collected the CT scans at end-expiration (EXP) and full-inspiration (INSP) of patients at 3 months after lung transplantation (LT). Lungs were segmented from both scans. INSP images were registered to EXP by optical flow to obtain maps of density variation (\u394HU) with pixel-by-pixel subtraction. We evaluated a classification of the pixels from maps of \u394HU in low ventilation (LV), consolidation (C), air trapping (AT) and healthy parenchyma (H). Patients who experienced uneventful early postoperative course after bilateral LT were enrolled. The figure shows the resulted composition of the parenchyma in 20 patients: LV=59.6\ub15.4%, C=1.7\ub10.4%, AT=0.06\ub10.05%, H=38.7\ub15.6%. To note that low ventilation pattern still affected the majority of lung tissue while consolidation and air trapping were negligible. Quantitative CT regional analysis may provide a significant advance in the interpretation of ventilation abnormalities after LT