CT findings of pneumonia after lung transplantation

Pulmonary transplant complications: a radiologic review

Lung transplantation has become the definitive treatment for end stage respiratory disease. Numbers and survival rates have increased over the past decade, with transplant recipients living longer and with greater comorbidities, resulting in greater complexity of care. Common and uncommon complications that occur in the immediate, early, intermediate, and late periods can have significant impact on the course of the transplant. Fortunately, advancements in surgery, medical care, and imaging as well as other diagnostics work to prevent, identify, and manage complications that would otherwise have a negative impact on survivability. This review will focus on contextualizing complications both categorically and chronologically, with highlights of specific imaging and clinical features in order to inform both radiologists and clinicians involved in post-transplant care.

Diagnostic difficulties in non-tuberculous mycobacterial infection in lung transplant recipients

Despite antimicrobial prophylaxis, 34% to 59% of lung transplant recipients experience severe life-threatening opportunistic infections, sometimes caused by Nontuberculous Mycobacteria (NTM) and Nocardia. Although differentiating these infections is of utmost importance for effective treatment, it can be challenging as they share morphological and growth characteristics. Therefore, culture remains the gold standard for laboratory confirmation. With the aid of novel molecular methods performed on the cultured organisms, diagnosis may be accomplished rapidly and precisely. We present a case of a lung transplant recipient with a pulmonary infection where long, thin, beaded, branching filamentous organisms were seen with Acid-Fast Bacilli (AFB) and Modified Gomori's Methenamine Silver (GMS) stains in bronchoalveolar lavage sample. Cytological characteristics led to the suspicion of a Nocardia species infection. However, culture and the PCR-restriction fragment length polymorphism analysis (PRA) identified M. fortuitum. Additionally, antibiotic resistance was detected, which aided in choosing the appropriate treatment. Therefore, to overcome such diagnostic difficulties to differentiate NTM and Nocardia, a multidisciplinary approach including culture, molecular methods, and cytology is needed to enhance clinical outcomes.

Complicações dos transplantes pulmonares na tomografia computadorizada: ensaio iconográfico

Resumo Transplantes pulmonares são procedimentos progressivamente mais realizados em todo o mundo como opção para tratamento de doenças pulmonares em estágio terminal. Apesar dos avanços laboratoriais, da técnica cirúrgica e da seleção de doadores e receptores, a mortalidade nesses procedimentos ainda é significativa, em razão de complicações típicas dos pacientes transplantados. Este trabalho consiste em uma revisão da literatura acerca do tema, ilustrando as complicações abordadas por meio de imagens de tomografia computadorizada.

Complications of lung transplantation on computed tomography: pictorial essay

Lung transplantation is becoming increasingly more common as an alternative treatment for end-stage lung disease. Despite advances in laboratory testing, surgical technique, and donor/recipient selection, lung transplantation is still associated with significant mortality, due to postoperative complications. This paper consists of a brief review of postoperative complications in lung transplant recipients, illustrating those complications with computed tomography images.

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 of pulmonary infections after lung transplantation: a pictorial essay of early and late computed tomography findings

Pulmonary infections are among the most common complications after lung transplants and a major cause of morbidity and mortality in these patients. Computed tomography is one of the main non-invasive diagnostic tools for detecting lung infections but characterizing the correct etiology may be very challenging. Indeed, although several pathogens show typical patterns at imaging, others, such as bacteria, may demonstrate quite unspecific features. Therefore, additional parameters, like the timing of the infection, should be evaluated to support the radiologists in narrowing the differential diagnoses. In fact, it has been demonstrated that several pathogens, like Candida albicans, usually occurring within the first month after the transplant, frequently occur at specific time points. Thus, aim of this review is to make radiologists and clinicians familiar with the computed tomography patterns of pulmonary infections occurring after lung transplant, considering the etiology and the time of onset, according to the extensive experience gained in our tertiary center.

Complications of Lung Transplantation: Update on Imaging Manifestations and Management

As lung transplantation has become the most effective definitive treatment option for end-stage chronic respiratory diseases, yearly rates of this surgery have been steadily increasing. Despite improvement in surgical techniques and medical management of transplant recipients, complications from lung transplantation are a major cause of morbidity and mortality. Some of these complications can be classified on the basis of the time they typically occur after lung transplantation, while others may occur at any time. Imaging studies, in conjunction with clinical and laboratory evaluation, are key components in diagnosing and monitoring these conditions. Therefore, radiologists play a critical role in recognizing and communicating findings suggestive of lung transplantation complications. A description of imaging features of the most common lung transplantation complications, including surgical, medical, immunologic, and infectious complications, as well as an update on their management, will be reviewed here. Keywords: Pulmonary, Thorax, Surgery, Transplantation Supplemental material is available for this article. © RSNA, 2021.

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.

Imaging of Lung Transplantation

Lung transplantation has become a viable treatment option for end-stage lung disease. Common indications for lung transplantation are chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis, cystic fibrosis, alpha-1 antitrypsin deficiency, and pulmonary arterial hypertension. Either single or bilateral lung transplantation can be performed, but bilateral lung recipients appear to have a better median survival than single lung recipients. Complications after lung transplantation are common and may have nonspecific clinical and radiologic manifestations. The time point at which these complications occur relative to the date of transplant is crucial in formulating a differential diagnosis and recognizing them accurately. Significant advances in imaging techniques and recognition of air trapping in exhalation images and other patterns /distribution of parenchymal abnormalities have led to routine use of HRCT for diagnostic evaluation in patients manifesting respiratory decline in the lung transplant recipient.

Imaging features of intrathoracic complications of lung transplantation: What the radiologists need to know

Lung transplantation has been a method for treating end stage lung disease for decades. Despite improvements in the preoperative assessment of recipients and donors as well as improved surgical techniques, lung transplant recipients are still at a high risk of developing post-operative complications which tend to impact negatively the patients’ outcome if not recognised early. The recognised complications post lung transplantation can be broadly categorised into acute and chronic complications. Recognising the radiological features of these complications has a significant positive impact on patients’ survival post transplantation. This manuscript provides a comprehensive review of the radiological features of post lung transplantations complications over a time continuum.

Critical Care Aspects of Lung Transplant Patients

Major strides have been made in lung transplantation during the 1990s and it has become an established treatment option for patients with advanced lung disease. Due to improvements in organ preservation, surgical techniques, postoperative intensive care, and immunosuppression, the risk of perioperative and early mortality (less than 3 months after transplantation) has declined [1]. The transplant recipient now has a greater chance of realizing the benefits of the long and arduous waiting period.

Despite these improvements, suboptimal long-term outcomes continue to be shaped by issues such as opportunistic infections and chronic rejection. Because of the wider use of lung transplantation and the longer life span of recipients, intensivists and ancillary intensive care unit (ICU) staff should be well versed with the care of lung transplant recipients.

In this clinical review, issues related to organ donation will be briefly mentioned. The remaining focus will be on the critical care aspects of lung transplant recipients in the posttransplant period, particularly ICU management of frequently encountered conditions. First, the groups of patients undergoing transplantation and the types of procedures performed will be outlined. Specific issues directly related to the allograft, including early graft dysfunction from ischemia-reperfusion injury, airway anastomotic complications, and infections in the setting of immunosuppression will be emphasized. Finally nonpulmonary aspects of posttransplant care and key pharmacologic points in the ICU will be covered.

What can happen after lung transplantation and the importance of the time since transplantation: radiological review of post-transplantation complications

Lung transplantation is the best treatment option in the final stages of diseases such as cystic fibrosis, pulmonary hypertension, chronic obstructive pulmonary disease, or idiopathic pulmonary fibrosis. Better surgical techniques and advances in immunosuppressor treatments have increased survival in lung transplant recipients, making longer follow-up necessary because complications can occur at any time after transplantation. For practical purposes, complications can be classified as early (those that normally occur within two months after transplantation), late (those that normally occur more than two months after transplantation), or time-independent (those that can occur at any time after transplantation). Many complications have nonspecific clinical and radiological manifestations, so the time factor is key to narrow the differential diagnosis. Imaging can guide interventional procedures and can detect complications early. This article aims to describe and illustrate the complications that can occur after lung transplantation from the clinical and radiological viewpoints so that they can be detected as early as possible.

Imaging in lung transplants: Checklist for the radiologist

Post lung transplant complications can have overlapping clinical and imaging features, and hence, the time point at which they occur is a key distinguisher. Complications of lung transplantation may occur along a continuum in the immediate or longer postoperative period, including surgical and mechanical problems due to size mismatch and vascular as well as airway anastomotic complication, injuries from ischemia and reperfusion, acute and chronic rejection, pulmonary infections, and post-transplantation lymphoproliferative disorder. Life expectancy after lung transplantation has been limited primarily by chronic rejection and infection. Multiple detector computed tomography (MDCT) is critical for evaluation and early diagnosis of complications to enable selection of effective therapy and decrease morbidity and mortality among lung transplant recipients.

Lung Transplantation

The first human lung transplantation (LuTX) was performed by Dr James Hardy (Hardy et al. 1963) in June 1960 at the University of Mississippi in a patient with unresectable lung cancer and obstructive pneumonitis. The patient received immunosuppression with azathioprine (Aza) and irradiation, but he died due to renal failure after 17 days.

Oxygen-sensitive 3He-MRI in bronchiolitis obliterans after lung transplantation

Oxygen-sensitive 3He-MRI was studied for the detection of differences in intrapulmonary oxygen partial pressure (pO2) between patients with normal lung transplants and those with bronchiolitis obliterans syndrome (BOS). Using software developed in-house, oxygen-sensitive 3He-MRI datasets from patients with normal lung grafts (n = 8) and with BOS (n = 6) were evaluated quantitatively. Datasets were acqiured on a 1.5-T system using a spoiled gradient echo pulse sequence. Underlying diseases were pulmonary emphysema (n = 10 datasets) and fibrosis (n = 4). BOS status was verified by pulmonary function tests. Additionally, 3He-MRI was assessed blindedly for ventilation defects. Median intrapulmonary pO2 in patients with normal lung grafts was 146 mbar compared with 108 mbar in patients with BOS. Homogeneity of pO2 distribution was greater in normal grafts (standard deviation pO2 34 versus 43 mbar). Median oxygen decrease rate during breath hold was higher in unaffected patients (-1.75 mbar/s versus -0.38 mbar/s). Normal grafts showed fewer ventilation defects (5% versus 28%, medians). Oxygen-sensitive 3He-MRI appears capable of demonstrating differences of intrapulmonary pO2 between normal lung grafts and grafts affected by BOS. Oxygen-sensitive 3He-MRI may add helpful regional information to other diagnostic techniques for the assessment and follow-up of lung transplant recipients.

Pulmonary infections in transplantation pathology

CONTEXT

Pulmonary infections are common and often life-threatening in solid organ and stem cell transplant recipients. Understanding their pathology is critical to making improvements in care and survival as well as in surgical techniques, immunosuppression management, prophylaxis, and treatment. Pulmonary infections are particularly common and serious in the susceptible population of lung transplant recipients.

OBJECTIVE

To summarize recent updates in the field for opportunistic infections and some common pathogens, and to consider the role of the diagnostic pulmonary histopathologist as well as advances in molecular diagnosis.

DATA SOURCES

This work is based on a selected review of the relevant medical and scientific literature, with emphasis on lung transplantation experience gained during 2 decades of practice.

CONCLUSIONS

Pulmonary infections in transplant recipients present a diagnostic challenge and are a continuing source of mortality and morbidity despite improvement in prophylaxis and treatment. Accurate diagnosis requires multidisciplinary input from clinicians, radiologists, and pathology disciplines as well as complementary molecular methods.

Postoperative complications of lung transplantation: radiologic findings along a time continuum

In the past decade, lung transplantation has become established as an accepted therapy for end-stage pulmonary disease. Complications of lung transplantation that may occur in the immediate or longer postoperative term include mechanical problems due to a size mismatch between the donor lung and the recipient thoracic cage; malposition of monitoring tubes and lines; injuries from ischemia and reperfusion; acute pleural events; hyperacute, acute, and chronic rejection; pulmonary infections; bronchial anastomotic complications; pulmonary thromboembolism; upper-lobe fibrosis; primary disease recurrence; posttransplantation lymphoproliferative disorder; and native lung complications such as hyperinflation, malignancy, and infection. Radiologic imaging--particularly chest radiography, computed tomography (CT), and high-resolution CT--is critical for the early detection, evaluation, and diagnosis of complications after lung transplantation. To enable the selection of an effective and relevant course of therapy and, ultimately, to decrease morbidity and mortality among lung transplant recipients, radiologists at all levels of experience must be able to recognize and understand the imaging manifestations of posttransplantation complications.

Pulmonary nocardiosis after lung transplantation: CT findings in 7 patients and review of the literature

OBJECTIVE

The purpose of this study is to review reported radiographic clues to the diagnosis of pulmonary nocardiosis, as well as to describe and illustrate the high-resolution computed tomography findings of 7 patients with pulmonary nocardiosis after lung transplantation.

CONCLUSIONS

Computed tomography findings of pulmonary nocardiosis after lung transplantation consist predominantly of nodules and cavitary lesions without any significant zonal or anatomic distribution. The diagnosis of pulmonary nocardiosis requires a high index of suspicion, as presenting symptoms are nonspecific, initial visualization is often not possible with routine stains, and identification requires prolonged cultures.

[Heart and heart-lung transplants thorax complications: major radiologic forms]

Bipulmonary and cardiopulmonary transplantations are among the most difficult to perform, with a 10-year survival rate estimated at 33%. This low rate can be attributed to thoracic complications that can be classified into three distinct groups: 1) early complications, occurring in the first 30 days after transplantation (hemothorax, diaphragmatic paralysis, reperfusion edema, hydric overloading, acute rejection); 2) late complications that occur beyond the first month (bronchiolitis obliterans syndrome, bronchic stenosis, sirolimus-induced lung disorders, initial disease recurrence); and 3) infections classed separately because of their high morbidity and mortality (thoracic wall abscess, bacterial and viral pneumonia, CMV, pneumocystosis, Aspergillus necrotizing bronchitis). Imaging is essential in screening and diagnosing these complications as part of the clinician's monitoring throughout the rest of the transplant recipient's life. In diagnosis, combined with clinical and biological data, imaging has its place in delaying the onset of these diseases.

Computed tomographic features of Legionella pneumophila pneumonia in 38 cases

PURPOSE

To characterize the imaging features of Legionella pneumophila pneumonia (LPP).

SUBJECTS AND METHODS

Imaging findings of computed tomography (CT) in 38 cases of microbiologically or serologically determined LPP were analyzed and compared with those of 35 cases of Streptococcus pneumoniae pneumonia.

RESULTS

In cases with LPP, abnormal opacities were distributed in a single lobe in 5 cases, in multiple lobes unilaterally in 10 cases, and multifocally and bilaterally in 23 cases. All cases showed consolidation and/or ground glass opacity in lung fields. Sharply demarcated peribronchovascular foci of consolidation intermingled with ground glass opacity were noted in 24 cases (24 of 38, 63%), whereas imaging features were seen in only 3 cases (3 of 35, 9%) of Streptococcus pneumoniae pneumonia. These CT patterns have nothing to do with clinical features such as age, sex, severity of disease, and time between onset of disease and CT examination.

CONCLUSIONS

Imaging features of LPP on CT include bilateral and unilateral single and multifocal consolidation and ground opacity. Sharply demarcated peribronchovascular foci of consolidation intermingled with ground glass opacity seem to be one of the most frequent CT appearances of LPP.

Pulmonary Complications of Transplantation: Radiographic Considerations

The aim of this article is to clarify radiographic definitions associated with common parenchymal patterns encountered in the transplant population and to discuss the most common pathologic causes responsible for each pattern. The article also touches on radiographic findings signifying complications of other intrathoracic structures, including the airways, pleural space, and mediastinum.

High-resolution computed tomography (HRCT) of lung infections in non-AIDS immunocompromised patients

Non-AIDS immunocompromised patients are susceptible to infections by a wide range of organisms. In the past several decades, advances in the treatment of cancer, organ transplantation, and immunosuppressive therapy have resulted in large numbers of patients who develop abnormalities in their immune system. Moreover, mildly impaired host immunity as it occurs in chronic debilitating illness, diabetes mellitus, malnutrition, alcoholism, advanced age, prolonged corticosteroid administration, and chronic obstructive lung disease have also been regarded as predisposing factors of pulmonary infections. Imaging plays a crucial role in the detection and management of patients with pulmonary infectious diseases. When pulmonary infection is suspected, knowledge of the varied radiographic manifestations will narrow the differential diagnosis, helping to direct additional diagnostic measures and serving as an ideal tool for follow-up examinations. Combination of pattern recognition with knowledge of the clinical setting is the best approach to pulmonary infection occurring in the immunocompromised patients.

Cytomegalovirus pneumonitis presenting small nodular opacities

Diffuse pulmonary small nodules and pyrexia suddenly developed in a 27-year-old woman during immunosuppressive treatment for viral-associated hemophagocytic syndrome. Miliary tuberculosis was suspected, however, bone marrow biopsy did not support the diagnosis. Lung biopsy revealed interstitial pneumonitis admixed with characteristic inclusion-bearing cells, and cytomegalovirus (CMV) DNA was demonstrated in polymerase chain reaction using bronchoalveolar lavage cells, establishing the diagnosis of CMV pneumonitis. No other opportunistic pathogens were identified, and the pneumonitis was subsided due to administration of gancyclovir. The present case illustrates CMV pneumonitis as a differential diagnosis for small nodular opacities which develop in immunocompromised patients.

Pulmonary complications of solid organ and hematopoietic stem cell transplantation

The ability to successfully transplant solid organs and hematopoietic stem cells represents one of the landmark medical achievements of the twentieth century. Solid organ transplantation has emerged as the standard of care for select patients with severe vital organ dysfunction and hematopoietic stem cell transplantation has become an important treatment option for patients with a wide spectrum of nonmalignant and malignant hematologic disorders, genetic disorders, and solid tumors. Although advances in surgical techniques, immunosuppressive management, and prophylaxis and treatment of infectious diseases have made long-term survival an achievable goal, transplant recipients remain at high risk for developing a myriad of serious and often life-threatening complications. Paramount among these are pulmonary complications, which arise as a consequence of the immunosuppressed status of the recipient as well as from such factors as the initial surgical insult of organ transplantation, the chemotherapy and radiation conditioning regimens that precede hematopoietic stem cell transplantation, and alloimmune mechanisms mediating host-versus-graft and graft-versus-host responses. As the population of transplant recipients continues to grow and as their care progressively shifts from the university hospital to the community setting, knowledge of the pulmonary complications of transplantation is increasingly germane to the contemporary practice of pulmonary medicine.

Lung retransplantation for bronchiolitis obliterans syndrome: long-term follow-up in a series of 15 recipients

BACKGROUND

Although lung retransplantation is the only definitive therapeutic option in lung recipients with bronchiolitis obliterans syndrome (BOS), its value remains a considerable source of controversy. We report our experience of retransplantation for BOS performed in our center since 1988.

METHODS

Between 1988 and 2002, 15 lung retransplantations for BOS were performed. Patient survival, causes of death, long-term functional status, and BOS recurrence rate were reviewed.

RESULTS

The retransplantation procedure was single-lung transplantation (SLT) in all cases (ipsilateral SLT, n = 4; contralateral SLT, n = 9; SLT after previous double-lung transplantation, n = 2). The median time between primary lung transplantation and retransplantation was 31 months (range, 12 to 39 months). The median follow-up duration of the 10 patients surviving beyond 6 months was 49.5 months (range, 16.5 to 105 months), and 5 patients were followed up for > 5 years. Actuarial survival rates at 1 year, 2 years, and 5 years after retransplantation were 60%, 53%, and 45%, respectively. Ten patients died during long-term follow-up, 6 of them from infection (60%). The retained graft was the initial site of the fatal infection in four of these six patients (66%). Two other patients with a retained graft experienced disabling chronic purulent expectoration arising from the old graft. In the 10 patients surviving beyond 6 months, mean best FEV(1) was 58 +/- 13% of predicted (+/- SD), and actuarial freedom from BOS (stage 1, 2, or 3) at 1 year, 3 years, and 5 years was 90%, 72%, and 66%, respectively.

CONCLUSION

Lung retransplantation offered a viable therapeutic option for selected lung recipients with BOS. Given the morbidity and mortality related to the retained graft, we now favor replacement of the primary graft when retransplantation is considered.

Imaging of the chest after lung transplantation

Lung transplantation is a well-accepted treatment for numerous lung diseases when medical or surgical therapy is ineffective or unavailable and the patient has a limited life expectancy (usually less than 2 to 3 years). When appropriate, single-lung transplantation is the preferred procedure because of a critical shortage of available donor lungs. Preoperative imaging is useful for selecting which lung should be transplanted, size matching between donor lung and recipient thorax, and screening for malignancy. Cardiac-related deaths, infection, and primary graft failure are the leading causes of perioperative death. Obliterative bronchiolitis is the "Achilles heel" of lung transplantation and accounts for the largest number of late deaths. This article reviews the preoperative, perioperative, and postoperative considerations and the utility of radiologic imaging after lung transplantation.

HRCT findings in the lungs of primary care patients with lower respiratory tract infection

PURPOSE

To survey the prevalence and type of lung patterns detectable at high-resolution CT (HRCT) in a primary care population seeking help for cough and fever.

MATERIAL AND METHODS

The HRCT patterns of 103 patients obtained at the primary visit to a municipal health centre for cough and fever were evaluated. Forced expiratory examinations were obtained in 93 patients.

RESULTS

Lower respiratory tract infection (LRTI)-related findings (present at inclusion, healed at follow-up, not explained by any other factor) were seen in 19 patients (18.7%), of whom 11 also showed opacities, even though of lesser extent, at conventional chest radiography. The following patterns were found: ground-glass opacity (58%), discrete consolidations (52%), confluent consolidations (16%; 1 case with an air bronchogram), air space nodules (10%), peribronchovascular thickening (37%), tree-in-bud pattern (26%), free pleural fluid (5%), and septal thickening (5%). An expiratory mosaic pattern was seen in 19 (20%) out of 93 patients. In addition, lymph node enlargement (>1 cm) was recorded in 7 patients out of 103.

CONCLUSION

HRCT is more sensitive than chest radiography in detecting LRTI-related lung lesions in a primary care population. The pattern typically comprises subtle scattered polymorphous opacities with varying attenuation affecting several lung segments. LRTI-related HRCT pattern deserves consideration as a differential diagnostic alternative in patients examined due to any lower respiratory tract symptoms.