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.

Imaging Course of Lung Transplantation: From Patient Selection to Postoperative Complications.

Lung transplant is increasingly performed for the treatment of end-stage lung disease. As the number of lung transplants and transplant centers continues to rise, radiologists will more frequently participate in the care of patients undergoing lung transplant, both before and after transplant. Potential donors and recipients undergo chest radiography and CT as part of their pretransplant assessment to evaluate for contraindications to transplant and to aid in surgical planning. After transplant, recipients undergo imaging during the postoperative hospitalization and also in the long-term outpatient setting. Radiologists encounter a wide variety of conditions leading to end-stage lung disease and a myriad of posttransplant complications, some of which are unique to lung transplantation. Familiarity with these pathologic conditions, including their imaging findings and their temporal relationship to the transplant, is crucial to accurate radiologic interpretation. Knowledge of the surgical techniques and expected postoperative appearance prevents confusing normal posttransplant imaging findings with complications. A basic understanding of the indications, contraindications, and surgical considerations of lung transplant aids in imaging interpretation and protocoling and also facilitates communication between radiologists and transplant physicians. Despite medical and surgical advances over the past several decades, lung transplant recipients currently have an average posttransplant life expectancy of only 6.7 years. As members of the transplant team, radiologists can help maximize patient survival and hopefully increase posttransplant life expectancy and quality of life in the coming decades. ©RSNA, 2021 An invited commentary by Bierhals is available online. Online supplemental material is available for this article.

Renal sympathetic denervation: MDCT evaluation of the renal arteries.

OBJECTIVE: Percutaneous transluminal renal sympathetic denervation is a new treatment of refractory systemic hypertension. The purpose of this study was to assess the clinical utility of MDCT to evaluate the anatomic configuration of the renal arteries in the context of renal sympathetic denervation. MATERIALS AND METHODS: Two readers retrospectively evaluated the MDCT renal artery scans of 90 patients (mean age, 70 ± 13 years; range, 32-98 years). Analysis included the number of renal arteries on each side, ostial shape and size, angle off the aorta, branching pattern, degree of tortuosity, and distance to adjacent vascular structures. RESULTS: Sixty-five patients had one, 23 had two, and two had three renal arteries on one side. One hundred forty-six arteries were funnel-shaped (72 left and 74 right; mean ostial diameter, 0.9 ± 0.2 cm tapering to 0.6 ± 0.1 cm). The mean tortuosity index was 1.1 (range, 1 [no tortuosity] to 3.1). Compared with the left renal artery, the right renal artery was longer (4.0 ± 0.9 cm vs 5.0 ± 1.2 cm, p ≤ 0.001), originated at a more acute angle on axial (67° vs 98°, p < 0.05) and coronal images (57° ± 16° vs 65° ± 14°, p < 0.05), was significantly closer to the superior mesenteric artery (1.0 ± 0.7 cm vs 1.6 ± 1.2 cm, p < 0.001), and came in closer contact with venous structures (0.0 ± 0.1 vs 0.2 ± 0.9, p < 0.05). CONCLUSION: Our findings suggest MDCT of the renal arteries is an informative investigation in patients undergoing renal sympathetic denervation, providing data on the number and size of renal branches, ostial shape, and proximity to adjacent venous structures.

Structured reporting in portable chest radiographs: An essential tool in the diagnosis of COVID-19.

PURPOSE: To date, the majority of chest imaging studies in COVID-19 pneumonia have focused on CT. Evidence for the utility of chest radiographs (CXRs) in this population is less robust. Our objectives were to develop a systematic approach for reporting likelihood of COVID-19 pneumonia on CXRs, to measure the interobserver variability of this approach and to evaluate the diagnostic performance of CXRs compared to real-time reverse transcription polymerase chain reaction (RT-PCR). METHOD: Retrospective review of patients suspected of having COVID-19 pneumonia who attended our emergency department and underwent both CXR and a RT-PCR were included. Two radiologists reviewed the CXRs, blind to the RT-PCR, and classified them according to a structured reporting template with five categories (Characteristic, High Suspicion, Indeterminate, Unlikely and Normal) which we devised. For analysis of diagnostic accuracy, Characteristic and High Suspicion CXRs were considered positive and the remaining categories negative. Concordance between the two assessors was also measured. RESULTS: Of 582 patients (51 +/- 20 years), 143/582 (24.6 %) had a positive RT-PCR. The absolute concordance between the two assessors was 71.1 % (414/582) with a Fleiss-Cohen-weighted Cohen's κ of 0.81 (95 % confidence interval, 0.78-0.85). A patient with a positive CXR had an 88 % (95 % CI 80-96 %) probability of having a positive RT-PCR during a period of high incidence, early in the COVID-19 pandemic. CONCLUSION: Using a structured approach, a positive CXR had a high likelihood of predicting a positive RT-PCR, with good interrater reliability. CXRs can be useful in identifying new cases of COVID-19.

Spectrum of Lung Adenocarcinoma.

Lung cancer remains the most common cause of cancer death in the United States of America and worldwide despite continued advances in lung cancer screening as well as surgical, medical, and radiation oncological treatments. Adenocarcinoma is the most common histological subtype of primary lung cancer and has recently been reorganized into a spectrum ranging from preinvasive lesions to invasive adenocarcinoma. An understanding of the pathology, diagnosis, and management of the spectrum of lung adenocarcinoma is more important than ever, considering the central role of the radiologist. The aim of this review is to describe the subtypes of the lung adenocarcinoma spectrum in terms of histological and imaging features, their pattern of growth on imaging, management, staging, and evolving knowledge of tumor genetics.