Radiological findings of complications after lung transplantation

Abstract

Complications following lung transplantation may impede allograft function and threaten patient survival. The five main complications after lung transplantation are primary graft dysfunction, post-surgical complications, alloimmune responses, infections, and malignancy. Primary graft dysfunction, a transient ischemic/reperfusion injury, appears as a pulmonary edema in almost every patient during the first three days post-surgery. Post-surgical dysfunction could be depicted on computed tomography (CT), such as bronchial anastomosis dehiscence, bronchial stenosis and bronchomalacia, pulmonary artery stenosis, and size mismatch. Alloimmune responses represent acute rejection or chronic lung allograft dysfunction (CLAD). CLAD has three different forms (bronchiolitis obliterans syndrome, restrictive allograft syndrome, acute fibrinoid organizing pneumonia) that could be differentiated on CT. Infections are different depending on their time of occurrence. The first post-operative month is mostly associated with bacterial and fungal pathogens. From the second to sixth months, viral pneumonias and fungal and parasitic opportunistic infections are more frequent. Different patterns according to the type of infection exist on CT. Malignancy should be depicted and corresponded principally to post-transplantation lymphoproliferative disease (PTLD). In this review, we describe specific CT signs of these five main lung transplantation complications and their time of occurrence to improve diagnosis, follow-up, medical management, and to correlate these findings with pathology results.Key Points• The five main complications are primary graft dysfunction, surgical, alloimmune, infectious, and malignancy complications.• CT identifies anomalies in the setting of unspecific symptoms of lung transplantation complications.• Knowledge of the specific CT signs can allow a prompt diagnosis.• CT signs maximize the yield of bronchoscopy, transbronchial biopsy, and bronchoalveolar lavage.• Radiopathological correlation helps to understand CT signs after lung transplantation complications.

Bronchiolitis and Bronchiolar Disorders

“…91 As for bronchiolitis obliterans after lung transplantation, histopathological confirmation of diagnosis is rarely obtained, and BOS is suspected in patients with airflow obstruction and air trapping on CT scans, usually in the presence of extrapulmonary chronic GVH disease. 108 The overall prevalence of bronchiolitis obliterans after HSCT is reported by different centers to be between 1.2 and 11% 109 and occurs at a median time of 15 to 18 months after transplantation. 109 Histopathological studies show heterogeneous lesions in different patients, but also within the same patient, suggesting that lesions of different ages co-exist; lymphocytic (cellular) bronchiolitis seems to have better prognosis.…”

Imaging indications and findings in evaluation of lung transplant graft dysfunction and rejection

“…Chest CT may show ground-glass opacities, consolidation, and interstitial and interlobular septal thickening ( Fig. 1) [2,3,18].…”

“…They include ground-glass opacities, consolidation, and interstitial thickening with or without pleural effusions ( Fig. 4) [3,25,26]. Significant clinical and radiographic improvement after early administration of high dose of corticosteroids provides additional supporting evidence for acute rejection [27].…”

“…Despite the improved outcomes, several complications can develop during the early postoperative period as well as later in the time course, affecting quality of life and contributing to mortality. Important complications in the early postoperative course include surgical complications, infection, primary graft dysfunction, acute rejection, and in later course, chronic lung allograft dysfunction, infection, and posttransplant lymphoproliferative disorder [2,3]. Difficulties in diagnosis arise from the non-specific clinical presentation of these entities, and the frequent coexistence of multiple complications in the same patient.…”

“…Computed tomography (CT) is the imaging test of choice for evaluating lung graft complications and dysfunction. However, because CT findings can be non-specific, especially in the early postoperative period, knowledge of the clinical context, including symptoms, time course of the presentation since transplant, and correlation with other investigations such as pulmonary function tests, echocardiography, and bronchoscopy helps in narrowing the differential diagnosis (Table 1) [2][3][4]. Other imaging tools such as magnetic resonance imaging (MRI) and positron-emission tomography (PET) are helpful in specific clinical scenarios.…”