Diagnosis of pulmonary complications associated with lung transplantation in children: value of CT vs histopathologic studies

Multidetector computed tomography of pediatric large airway diseases: state-of-the-art

Advances in multidetector computed tomography (MDCT) technology have given rise to improvements in the noninvasive and comprehensive assessment of the large airways in pediatric patients. Superb two-dimensional and three-dimensional reconstruction MDCT images have revolutionized the display of large airways and enhanced the ability to diagnose large airway diseases in children. The 320-MDCT scanner, which provides combined detailed anatomic and dynamic functional information assessment of the large airways, is promising for the assessment of dynamic large airway disease such as tracheobronchomalacia. This article discusses imaging techniques and clinical applications of MDCT for assessing large airway diseases in pediatric patients.

Multidetector computed tomography and 3-dimensional imaging: preoperative evaluation of thoracic vascular and tracheobronchial anomalies and abnormalities in pediatric patients

In the past decade, rapid technical developments and advancements of multidetector computed tomography (MDCT) have revolutionized the preoperative imaging evaluation of thoracic vascular and tracheobronchial anomalies and abnormalities in infants and children. Multidetector computed tomography enables noninvasive, rapid, high-resolution, and 3-dimensional (3D) imaging of the thorax in pediatric patients that provides comprehensive preoperative surgical guidance for pediatric surgeons. With the increasing availability of MDCT and 3D imaging, a practical review is needed for the pediatric surgeon of the evolving role of these techniques in the preoperative evaluation of surgical lesions in infants and children. This article focuses on the review of advantages and disadvantages of MDCT in comparison to other imaging modalities, 2D and 3D imaging postprocessing techniques, and MDCT and 3D imaging appearance of various thoracic vascular and tracheobronchial anomalies and abnormalities in pediatric patients. The primary aim of this article was to facilitate the pediatric surgeons' ability to successfully incorporate MDCT and 3D imaging as a routine preoperative imaging tool for the evaluation of thoracic surgical lesions in infants and children.

Computed tomography findings of postoperative complications in lung transplantation

Due to the increasing number and improved survival of lung transplant recipients, radiologists should be aware of the imaging features of the postoperative complications that can occur in such patients. The early treatment of complications is important for the long-term survival of lung transplant recipients. Frequently, HRCT plays a central role in the investigation of such complications. Early recognition of the signs of complications allows treatment to be initiated earlier, which improves survival. The aim of this pictorial review was to demonstrate the CT scan appearance of pulmonary complications such as reperfusion edema, acute rejection, infection, pulmonary thromboembolism, chronic rejection, bronchiolitis obliterans syndrome, cryptogenic organizing pneumonia, post-transplant lymphoproliferative disorder, bronchial dehiscence and bronchial stenosis.

Pediatric lung transplantation: perspectives for the pathologist

Lung transplantation offers life-saving and life-extending treatment for children and adolescents with congenital and acquired forms of pulmonary and pulmonary vascular disease, for whom medical therapy is ineffective or insufficient for sustained response. This review summarizes the pathology related to lung transplantation for the practicing pediatric pathologist and also highlights aspects of lung transplantation unique to the pediatric population. Clinical issues related to availability of organs, candidate eligibility, surgical technique, and postoperative monitoring are discussed. Pathologic evaluation of routine surveillance transbronchial biopsies requires attention to acute cellular rejection, opportunistic infection, and other forms of acute and resolving lung injury. These findings are correlated in some cases with endobronchial biopsies and bronchoalveolar lavage as adjunctive tools in surveillance. Open or thoracoscopic biopsies also have diagnostic utility in cases with acute or chronic graft deterioration of uncertain etiology. Future challenges in pediatric lung transplantation are similar to those in the adult population, with continued efforts focused on prolonging graft survival, prevention of bronchiolitis obliterans syndrome due to chronic cellular rejection, and evaluation of humoral rejection.

Post-lung transplantation bronchiolitis obliterans syndrome: usefulness of expiratory thin-section CT for diagnosis

PURPOSE

To assess the usefulness of thin-section expiratory computed tomography (CT), as compared with that of thin-section inspiratory CT, in detecting airway obstruction and air trapping in pediatric lung transplant recipients with bronchiolitis obliterans syndrome (BOS).

MATERIALS AND METHODS

Thin-section CT scans were obtained at full inspiration and end expiration in 21 pediatric lung transplant recipients with proved BOS and in 41 transplant recipients with normal airways. True diagnosis was based on pulmonary function test results. Inspiration CT scans were scored for extent of decreased attenuation of the lung parenchyma; expiration CT scans were scored for extent of air trapping.

RESULTS

The sensitivity of inspiratory CT for enabling diagnosis of BOS was 71%; the specificity, 78%; the positive predictive value, 62%; and the negative predictive value, 84%. The sensitivity of expiratory CT for enabling diagnosis of BOS was 100%; the specificity, 71%; the positive predictive value, 64%; and the negative predictive value, 100%. Expiratory CT scores correlated more strongly (rho = 0.75, P <.01) with pulmonary function test-based scores than did inspiratory CT scores (rho = 0.48, P <.01). Nominal logistic regression analysis revealed that expiratory CT was a more powerful predictor of true diagnosis (P <.01) than was inspiratory CT (P =.10).

CONCLUSION

Expiratory CT is sensitive for depicting BOS-related airway abnormalities and may be more useful than inspiratory CT for diagnosis of small airway obstruction.

Complications (excluding hyperinflation) involving the native lung after single-lung transplantation: incidence, radiologic features, and clinical importance

PURPOSE

To determine the incidence, importance, and radiologic features of native lung complications after single-lung transplantation.

MATERIALS AND METHODS

Seventeen (15%) of 111 single-lung transplant recipients developed native lung complications (excluding hyperinflation) 0-58 months (mean, 17 months) after transplantation. Complaints at presentation, culture or histopathologic results, diagnostic or therapeutic procedures, and outcome were recorded. Chest radiographs (n = 17) and computed tomographic (CT) scans (n = 8) obtained at time of diagnosis were reviewed. Serial radiographs were assessed for disease progression or improvement.

RESULTS

The most common complications were infection (n = 10), caused by bacteria (n = 4), fungi (n = 4), or mycobacteria (n = 2), typically manifested as lobar or segmental opacities on chest radiographs or CT scans. Lung cancer manifested as a solitary well-circumscribed nodule (n = 1), multiple nodules (n = 1), or a hilar mass (n = 1). Five (29%) of 17 patients died of native lung complications. Seven patients underwent mediastinoscopy (n = 3), lobectomy (n = 2), thoracoscopic wedge resection (n = 2), tube thoracostomy (n = 2), or pneumonectomy (n = 1) for diagnosis or treatment.

CONCLUSION

Native lung complications occurred in 17 (15%) single-lung transplant recipients, were most commonly due to infection or lung cancer, and caused serious morbidity or mortality in 12 (71%) of 17 patients affected.

CT findings of pneumonia after lung transplantation

OBJECTIVE

The purpose of this study was to describe the CT findings of pneumonia in patients who had undergone lung transplantation and to determine if specific imaging features existed for the different infectious organisms.

MATERIALS AND METHODS

The authors retrospectively reviewed the medical records of 262 patients with transplanted lungs at two lung transplantation centers. Patients with a documented pneumonia and correlating abnormal findings on CT (39 patients with 45 pneumonias) were included in the study. RESULTS. Of 45 pneumonias, Cytomegalovirus (n = 15), Pseudomonas (n = 7), and Aspergillus (n = 8) organisms were the most common single responsible infectious agents. The most common CT findings of pneumonia consisted of consolidation (n = 37; 82%), ground-glass opacification (n = 34; 76%), septal thickening (n = 33; 73%), pleural effusion (n = 33; 73%), and multiple (n = 25; 56%) or single (n = 2; 4%) nodules. No significant difference in the prevalence of findings was revealed among bacterial, viral, and fungal pneumonias (p >.05, chisquare test). Of 25 pneumonias in patients with a single transplanted lung, parenchymal abnormalities involved both lungs in 12 (48%), only the transplanted lung in 11 (44%), and only the native lung in two (8%).

CONCLUSION

The manifestations revealed on CT of bacterial, viral, and fungal pneumonia after lung transplantation are similar, consisting of a combination of consolidation, ground-glass opacification, septal thickening, pleural effusion, or multiple nodules. Therefore, these findings cannot be used to suggest the infectious organisms in this patient population.

Pulmonary nodules in liver transplant recipients

Pulmonary nodules present a diagnostic dilemma in liver transplant recipients because of the broad differential diagnosis involved. Eleven of 155 (7.1%) liver transplant recipients at the Veterans Affairs Medical Center, Pittsburgh, developed pulmonary nodules. The underlying etiology included aspergillosis (3 cases), cryptococcosis (2), metastatic hepatocellular carcinoma (1), posttransplant lymphoproliferative disorder (1), Staphylococcus aureus (1), squamous cell carcinoma (1), adenocarcinoma of unknown primary site (1), and undifferentiated carcinoma (1). A review of the literature revealed 22 other liver transplant recipients with pulmonary nodules. There appears to be a definite relationship between time since transplantation and etiology of the nodule. Aspergillosis and bacterial infections appear early (within the first month), whereas nocardiosis, coccidiomycosis, tuberculosis, and cryptococcosis occur from 3 to 24 months posttransplantation. Metastatic hepatocellular carcinoma is a relatively common cause of pulmonary nodule and appears from 2 months to 2 years posttransplantation. Detection of skin lesions (indicating nocardiosis or cryptococcosis) and positive serologic tests may further narrow the diagnosis. However, radiographic appearances of nodules of differing etiology are relatively nonspecific, necessitating biopsy in virtually all cases.

Preoperative and postoperative imaging in the surgical management of pulmonary emphysema

For patients with emphysema, imaging studies have been useful for diagnostic purposes and for preoperative patient selection for surgical intervention, such as bullectomy, lung transplantation, and LVRS. Chest radiography is useful in evaluating hyperinflation. Inspiratory and expiratory films are used to estimate diaphragmatic excursion and air-trapping. CT scan is used to evaluate the anatomy and distribution of emphysema throughout the lungs, providing information clinically unobtainable by other means. Both imaging techniques are useful for detecting other disease processes. Radionuclide lung scanning also provides an estimate of target areas, volume occupying but nonfunctioning lung. Cohort studies utilizing these imaging techniques have demonstrated associations between preoperative characteristics and postoperative outcome. The imaging studies, especially the chest radiograph, have also played an important role in postoperative management. Many other imaging options are available, such as HRCT scan, quantitative CT scan, and single photon emission CT scan. Other techniques, such as MR imaging, may play a future role as well.

Pleural effusion from acute lung rejection

A single-lung transplant recipient developed an ipsilateral pleural effusion from acute lung rejection 2 weeks after transplantation. The pleural effusion was exudative and contained more than 80% lymphocytes on two separate determinations. Acute lung rejection should be added to the differential diagnosis of a lymphocyte-predominant exudative pleural effusion.

High-resolution CT in long-term follow-up after lung transplantation

OBJECTIVE

Our aim was to evaluate the development of changes on high-resolution CT (HRCT) associated with chronic pulmonary rejection.

MATERIALS AND METHODS

Repeated HRCT examinations were performed 140 times on 13 consecutive lung transplant recipients during a mean observation period of 26 months. The postoperative time interval to the first detection of each chronic change on CT was calculated and compared with the onset of chronic rejection. Bronchiolitis obliterans syndrome (BOS) or the histologic diagnosis of obliterative bronchiolitis was assessed by the published criteria of the International Society for Heart and Lung Transplantation.

RESULTS

BOS developed in eight patients, on an average, within 11.6 (+/-5.0) months. Histologic diagnosis was available from five patients. On HRCT, among the first identifiable chronic changes were volume contraction, decreased peripheral vascular and bronchial markings, and thickening of septal lines, all of which appeared between 7 (+/-5.0) and 11 (+/-6.8) months postoperatively. The mean interval for appearance of bronchodilatation was 12.5 (+/-8.7) months. Hyperlucency and mosaic phenomenon were identified, on an average, 16 (+/-6.3) and 21 (+/-7.3) months after transplantation.

CONCLUSION

On radiologic monitoring of lung recipients with HRCT, in addition to bronchodilatation. a special attention should be paid to the early chronic changes, including diminution of peripheral bronchovascular markings, thickening of septal lines, and volume reduction, which usually precede the establishment of the diagnosis of chronic rejection, whereas hyperlucency and mosaic phenomenon usually appear during more advanced BOS.

Acute rejection diagnosed with computed tomography in a porcine experimental lung transplantation model

The role of computed tomography (CT) in the diagnosis of acute rejection was studied in an experimental lung transplantation model, with 15 left lung allotransplantations and six autotransplantations performed on piglets weighing 16-24 kg. There were 31 episodes of acute rejection. In the allotransplantation group the development of acute rejection was monitored 115 times with CT, transbronchial biopsy (TBB) and bronchoalveolar lavage (BAL). The stages of acute rejection were 1) ill-defined centrilobular micronodules or minimal patchy ground-glass opacities. 2) dense, small-nodular infiltration or extensive ground-glass opacities, and bronchial wall thickening. 3) lung volume loss and dense, patchy ground-glass opacities and 4) consolidation of the lung. In the autotransplantation group monitoring was done 42 times. After allotransplantation, TBB and BAL suggested rejection 60 times and infection 23 times. CT had 86.7% sensitivity and 85.6% specificity. During the first month these figures were, respectively, 71.4% and 84.2%. Rising histologic grade was associated with increasing stage of acute rejection on CT, which thus proved to be a sensitive and specific method for diagnosing acute rejection of lung transplant.

Combined percutaneous lung biopsy and high-resolution computed tomography in the diagnosis and management of lung disease in children

Computed tomography-guided percutaneous lung biopsy is a well-recognized procedure for obtaining tissue for diagnosis in adults with interstitial lung diseases. Recently this methodology has been extended to pediatric practice. We have further refined this technique by employing high-resolution computed tomography (HRCT) under general anesthesia to obtain maximum anatomical detail. High-quality images are obtained that accurately define the extent of disease, and percutaneous biopsies are then taken from a suitable area of radiological abnormality using an 18G Monopty needle. Twenty-six investigations have been performed on 24 patients. The diagnosis was established from 14 biopsies, and histological and/or radiological information that contributed to patient management was obtained from a further 4 procedures. In 4 patients the histological findings were inconclusive, and the final diagnosis was only confirmed by open lung biopsy and/or other investigations. The procedure was generally well tolerated, although chest drainage for pneumothorax was required in two patients. HRCT-guided percutaneous lung biopsy is a useful initial approach to the diagnosis of interstitial lung disease in selected patients; the necessity of more invasive procedures such as open, thoracoscopic, or transbronchial lung biopsy can thus generally be avoided.