New Nodule-Newer Etiology

The role of radiology in addressing the challenge of lung cancer after lung transplantation

The importance of lung cancer as a complication of lung transplantation is increasingly recognised. It may become an important survival-limiting factor in lung transplant patients as management of other complications continues to improve and utilisation of extended criteria donors grows. Radiology can play a key role in tackling this issue at multiple stages in the transplantation pathway and follow-up process. Routine chest CT as part of pre-transplant recipient assessment (and donor assessment if available) can identify suspicious lung lesions with high sensitivity and detect chronic structural lung diseases such as pulmonary fibrosis associated with an increased risk of malignancy post-transplant. Pre-transplant CT also provides a comparison for later CT studies in the assessment of nodules or masses. The potential role of regular chest CT for lung cancer screening after transplantation is less certain due to limited available evidence on its efficacy. Radiologists should be cognisant of how the causes of pulmonary nodules in lung transplant patients may differ from the general population, vary with time since transplantation and require specific recommendations for further investigation/follow-up as general guidelines are not applicable. As part of the multidisciplinary team, radiology is involved in an aggressive diagnostic and therapeutic management approach for nodular lung lesions after transplant both through follow-up imaging and image-guided tissue sampling. This review provides a comprehensive overview of available clinical data and evidence on lung cancer in lung transplant recipients, and in particular an assessment of the current and potential roles of pre- and post-transplant imaging. KEY POINTS: • Lung cancer after lung transplantation may become an increasingly important survival-limiting factor as mortality from other complications declines. • There are a number of important roles for radiology in tackling the issue which include pre-transplant CT and supporting an aggressive multidisciplinary management strategy where lung nodules are detected in transplant patients. • The introduction of routine surveillance chest CT after transplant in addition to standard clinical follow-up as a means of lung cancer screening should be considered.

Indeterminate pulmonary nodule in lung allograft characterized using dual-energy computed tomography

Pulmonary nodules (PNs) arising in the lung transplant recipient pose a diagnostic challenge for providers. Conventional computed tomography (CT) has improved our ability to detect PNs in this population, but establishing a confident diagnosis with imaging alone remains difficult. Dual-energy spectral detector CT is a novel, emerging technology that provides insight into the radiographic behavior of PNs, and has potential in differentiating benign from malignant morphologies. Herein, we report a case of a PN in a lung transplant recipient whose initial diagnostic work-up was inconclusive, but then had the diagnosis rendered using a spectral detector CT.