Pulmonary Disease in Patients with AIDS: High-Resolution CT and Pathologic Findings

Chest CT Findings in Patients with HIV Presenting to the Emergency Department: A Single Institute Experience

PURPOSE

The aim of this study was to analyze chest CT imaging findings and relevant clinical factors in patients with HIV presenting to the emergency department (ED).

MATERIALS AND METHODS

A retrospective review was performed to identify patients with HIV who received chest CT imaging evaluation in the acute ED setting. Analyzed patients included adults with a known diagnosis of HIV who presented to the ED at a single tertiary care center between 2004 and 2020 and received chest CT imaging. Chest CT findings were assessed by 2 radiologist readers, and relevant clinical data were gathered. Statistical analysis was performed to determine if imaging and clinical factors demonstrate significant associations with CD4 count, viral load, and antiretroviral therapy status.

RESULTS

A total of 113 patients with HIV were identified who presented to the ED and underwent chest CT imaging evaluation (mean age 47 ± 11 years). Frequently detected chest CT findings included infectious pneumonia (24%), malignancy (11%), pleural effusion (17%), pericardial effusion (13%), and pulmonary embolism (4%). CD4 count, viral load, and active retroviral therapy demonstrated statistically significant associations with a number of key imaging and clinical factors, including presence of pneumonia, malignancy, average length of hospital admission, and survival.

CONCLUSION

Patients with HIV present with a wide range of imaging findings when presenting in the acute ED setting. CD4 count, viral load, and active retroviral therapy status demonstrate statistically significant associations with multiple key imaging findings and clinical factors. Chest CT plays an integral role in the clinical management of this unique patient population.

Pulmonary cannonballs in a patient with Acquired Immunodeficiency Syndrome (AIDS)

Pneumocystis jirovecii pneumonia (PJP) remains one of the most common and life-threatening complications in patients with AIDS. PJP typically presents subacutely with a dry cough, shortness of breath with exertion, fever, and bilateral ground-glass opacities on imaging. However, atypical imaging findings have been reported including cysts, isolated lymphadenopathy, and small to large nodules. This case highlights the importance of considering unusual presentations of a relatively common entity in order to prevent delays in diagnosis and treatment.

Infection in Immunocompromised Hosts: Imaging

Immunocompromised patients are encountered with increasing frequency in clinical practice. In addition to the acquired immunodeficiency syndrome (AIDS), therapy for malignant disease, and immune suppression for solid organ transplants, patients are now rendered immunosuppressed by advances in treatment for a wide variety of autoimmune diseases. The number of possible infecting organisms can be bewildering. Recognition of the type of immune defect and the duration and depth of immunosuppression (particularly in hematopoietic and solid organ transplants) can help generate a differential diagnosis. Radiologic imaging plays an important role in the detection and diagnosis of chest complications occurring in immunocompromised patients; however, chest radiography alone seldom provides adequate sensitivity and specificity. High-resolution computed tomography (CT) can provide better sensitivity and specificity, but even CT findings may be nonspecific findings unless considered in conjunction with the clinical context. Combination of CT pattern, clinical setting, and immunologic status provides the best chance for an accurate diagnosis. In this article, CT findings have been divided into 4 patterns: focal consolidation, nodules/masses, small/micronodules, and diffuse ground-glass attenuation/consolidation. Differential diagnoses are suggested for each pattern, adjusted for both AIDS and non-AIDS immunosuppressed patients.

Metastatic Angiosarcoma of the Scalp Presenting with Cystic Lung Lesions: A Case Report and Review of Cystic Lung Diseases

INTRODUCTION

Angiosarcomas are rare, malignant vascular tumors that affect endothelial cells of blood vessels. Angiosarcomas most commonly occur on the scalp or face of elderly individuals and are highly aggressive, with a 5-year survival rate below 15%. Cutaneous angiosarcomas often metastasize to the lung, where they can present with cystic lesions, solid lesions, pneumothorax, and/or hemothorax.

CASE PRESENTATION

We report the case of an 83-year-old woman who presented with a scalp lesion, which was initially thought to be caused by scalp trauma but was later found to be an angiosarcoma. She initially refused any therapy for the tumor. She returned several months later with a cough and shortness of breath and was found to have multiple pulmonary cysts. She was treated with paclitaxel, but her tumor did not respond to the therapy and she died 2 months later.

DISCUSSION

We discuss the common presentation of cutaneous angiosarcomas and their tendency to metastasize to the lung and present as cystic lesions. We also review the common conditions that can cause cystic changes in the lungs.

Imaging of Pulmonary Infections

Pulmonary infections have always been a cause of high morbidity and mortality, particularly in the pediatric and geriatric population and in immunocompromised hosts [1]. Pulmonary infections have various etiologies and have variegated patterns on radiographs and computed tomography (CT). Imaging plays an important role in the initial diagnosis and follow-up of various lung infections. Radiographs can be normal or non-specific during the initial evaluation, and CT findings may be more definitive. CT not only helps with the diagnosis but can also aid in management by guiding the diagnostic and therapeutic procedure. The pulmonary infections spread by direct or indirect contact with the infected host, droplet transmission, or an airborne spread. In rare cases, some infections can also be transmitted by vectors, namely, insect or animal hosts, and rarely by direct invasion from nearby infected organs. Pulmonary infections may have typical imaging patterns and distribution based on the mode of spread. There are a number of well-described imaging patterns of alveolar infections. The localization and morphological features on imaging may help in the diagnosis of infection and identification of mode of infection and, in certain cases, the microorganism responsible for the infection.

Pulmonary Kaposi's sarcoma in a female patient: Case report

Kaposi's sarcoma (KS) is a multicentric lymphoproliferative malignancy. Most of the time this tumor is confined to the skin and subcutaneous tissue, but it can present with widespread visceral involvement, such as in the lung. Pulmonary KS is the most frequent form in young adult males, in a ratio of 15:1. The disease usually affects individuals with low CD4 lymphocyte counts (<150-200 cells/mm3). We report a case of a female patient aged 35 years, with the presence of skin lesions, self-limiting episodes of diarrhea and weight loss of 15 kg for nearly 9 months, progressing to persistent fever. AIDS was diagnosed and biopsy of the lesions revealed Kaposi's sarcoma. Computed tomography of the chest showed peribronchovascular thickening, areas of ground glass opacity, condensations with air bronchograms surrounded by ground glass opacity (halo sign) and bilateral pleural effusion. The diagnosis of pulmonary KS is still a challenge, especially due to the occurrence of other opportunistic diseases that may also occur concurrently. Therefore, suspecting this diagnosis based on clinical and laboratory manifestations, and even more with CT findings, is fundamental, especially in patients who already have the cutaneous form of the disease.

Risk Factors Associated With Quantitative Evidence of Lung Emphysema and Fibrosis in an HIV-Infected Cohort

INTRODUCTION

The disease spectrum for HIV-infected individuals has shifted toward comorbid non-AIDS conditions including chronic lung disease, but quantitative image analysis of lung disease has not been performed.

OBJECTIVES

To quantify the prevalence of structural changes of the lung indicating emphysema or fibrosis on radiographic examination.

METHODS

A cross-sectional analysis of 510 HIV-infected participants in the multicenter Lung-HIV study was performed. Data collected included demographics, biological markers of HIV, pulmonary function testing, and chest computed tomographic examinations. Emphysema and fibrosis-like changes were quantified on computed tomographic images based on threshold approaches.

RESULTS

In our cohort, 69% was on antiretroviral therapy, 13% had a current CD4 cell count less than 200 cells per microliter, 39% had an HIV viral load greater than 500 copies per milliliter, and 25% had at least a trace level of emphysema (defined as >2.5% of voxels <-950HU). Trace emphysema was significantly correlated with age, smoking, and pulmonary function. Neither current CD4 cell count nor HIV viral load was significantly correlated with emphysema. Fibrosis-like changes were detected in 29% of the participants and were significantly correlated with HIV viral load (Pearson correlation coefficient = 0.210; P < 0.05); current CD4 cell count was not associated with fibrosis. In multivariable analyses including age, race, and smoking status, HIV viral load remained significantly correlated with fibrosis-like changes (coefficient = 0.107; P = 0.03).

CONCLUSIONS

A higher HIV viral load was significantly associated with fibrosis-like changes, possibly indicating early interstitial lung disease, but emphysematous changes were not related to current CD4 cell count or HIV viral load.

Multiple cystic lung disease

Multiple cystic lung disease represents a diverse group of uncommon disorders that can present a diagnostic challenge due to the increasing number of diseases associated with this presentation. High-resolution computed tomography of the chest helps to define the morphological aspects and distribution of lung cysts, as well as associated findings. The combination of appearance upon imaging and clinical features, together with extrapulmonary manifestations, when present, permits confident and accurate diagnosis of the majority of these diseases without recourse to open-lung biopsy. The main diseases in this group that are discussed in this review are lymphangioleiomyomatosis, pulmonary Langerhans cell histiocytosis and folliculin gene-associated syndrome (Birt–Hogg–Dubé); other rare causes of cystic lung disease, including cystic metastasis of sarcoma, are also discussed. Disease progression is unpredictable, and understanding of the complications of cystic lung disease and their appearance during evolution of the disease are essential for management. Correlation of disease evolution and clinical context with chest imaging findings provides important clues for defining the underlying nature of cystic lung disease, and guides diagnostic evaluation and management.

Thoracic diseases associated with HIV infection in the era of antiretroviral therapy: clinical and imaging findings

The human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) pandemic has entered its 4th decade. Since the introduction of combination antiretroviral therapy (ART) in 1996, the number of AIDS-related deaths has plateaued worldwide. Today, owing to the effectiveness of ART, the HIV-infected population is aging and HIV infection has become a chronic illness. Non-AIDS comorbidities are increasing, and the spectrum of HIV-related thoracic diseases is evolving. In developed countries, bacterial pneumonia has become more common than Pneumocystis pneumonia. Its imaging appearance depends on the responsible organism, most commonly Streptococcus pneumoniae. Mycobacterium tuberculosis continues to be a major threat. Its imaging patterns vary depending on CD4 count. Primary lung cancer and Hodgkin lymphoma are two important non-AIDS-defining malignancies that are increasingly encountered at chest imaging. Human herpesvirus 8, also known as Kaposi sarcoma-associated herpesvirus (KSHV), is strongly linked to HIV-related diseases, including Kaposi sarcoma, multicentric Castleman disease, KSHV inflammatory cytokine syndrome, and primary effusion lymphoma. Immune reconstitution inflammatory syndrome is a direct complication of ART whose manifestations vary with the underlying disease. Given the high rate of smoking among HIV-infected patients, chronic obstructive pulmonary disease is another important cause of morbidity and mortality. A high degree of suspicion is required for the early diagnosis of pulmonary arterial hypertension and lymphocytic interstitial pneumonia, given their nonspecific manifestations. Finally, multilocular thymic cyst manifests as a cystic anterior mediastinal mass. Recognition of the clinical and radiologic manifestations of these less traditional HIV-related diseases can expedite diagnosis and treatment in the ART era.

Pneumocystis Pneumonia in Human Immunodeficiency Virus-infected Adults and Adolescents: Current Concepts and Future Directions

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in human immunodeficiency virus–infected adults. Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, polymerase chain reaction has been shown to have a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for the evaluation of immunocompromised patients with suspected PCP and normal chest radiography. Trimethoprim–sulfamethoxazole (TMP-SMX) is the first-line agent for the treatment of mild to severe PCP, although it is often complicated with various side effects. Since TMP-SMX is widely used for the prophylaxis, the putative drug resistance is an emerging concern.

Single nodular opacity of granulomatous pneumocystis jirovecii pneumonia in an asymptomatic lymphoma patient

The radiologic findings of a single nodule from Pneumocystis jirovecii pneumonia (PJP) have been rarely reported. We described a case of granulomatous PJP manifesting as a solitary pulmonary nodule with a halo sign in a 69-year-old woman with diffuse large B cell lymphoma during chemotherapy. The radiologic appearance of the patient suggested an infectious lesion such as angioinvasive pulmonary aspergillosis or lymphoma involvement of the lung; however, clinical manifestations were not compatible with the diseases. The nodule was confirmed as granulomatous PJP by video-assisted thoracoscopic surgery biopsy.

Mimics in chest disease: interstitial opacities

Septal, reticular, nodular, reticulonodular, ground-glass, crazy paving, cystic, ground-glass with reticular, cystic with ground-glass, decreased and mosaic attenuation pattern characterise interstitial lung diseases on high-resolution computed tomography (HRCT). Occasionally different entities mimic each other, either because they share identical HRCT findings or because of superimposition of patterns. Idiopathic pulmonary fibrosis (IPF), fibrosis associated with connective tissue disease, asbestosis, end-stage sarcoidosis or chronic hypersensitivity pneumonitis (HP) may present with lower zone, subpleural reticular pattern associated with honeycombing. Lymphangiomyomatosis may be indistinguishable from histiocytosis or extensive emphysema. Both pulmonary oedema and lymphangitic carcinomatosis may be characterised by septal pattern resulting from thickened interlobular septa. Ill-defined centrilobular nodular pattern may be identically present in HP and respiratory bronchiolitis–associated with interstitial lung disease (RBILD). Sarcoidosis may mimic miliary tuberculosis or haematogenous metastases presenting with miliary pattern, while endobronchial spread of tuberculosis may be indistinguishable from panbronchiolitis, both presenting with tree-in-bud pattern. Atypical infection presenting with ground-glass mimics haemorrhage. Ground-glass pattern with minimal reticulation is seen in desquamative interstitial pneumonia (DIP), RBILD and non-specific interstitial pneumonia (NSIP). Obliterative bronchiolitis and panlobular emphysema may present with decreased attenuation pattern, while obliterative bronchiolitis, chronic pulmonary embolism and HP may manifest with mosaic attenuation pattern. Various mimics in interstitial lung diseases exist. Differential diagnosis is narrowed based on integration of predominant HRCT pattern and clinical history.

Teaching Points

• To learn about the different HRCT patterns, which are related to interstitial lung diseases.

• To be familiar with the more “classical” entities presenting with each HRCT pattern.

• To discuss possible overlap of different HRCT patterns and the more common mimics in each case.

• To learn about some clues that help differentiate the various diagnostic mimics on HRCT.

Recent advances in the diagnosis of Pneumocystis jirovecii pneumonia in HIV-infected adults

INTRODUCTION

Pneumocystis jirovecii pneumonia (PCP) is one of the most common opportunistic infections in HIV-infected adults. Although the microscopic demonstration of the organisms in respiratory specimens is still the golden standard of its diagnosis, recent advances in the diagnostic tools have been changing the situation.

AREAS COVERED

Colonization of Pneumocystis is highly prevalent among the general population and could be associated with the transmission and development of PCP in immunocompromised individuals. Nested or conventional polymerase chain reaction (PCR) has a high sensitivity, detecting Pneumocystis DNA in induced sputum or oropharyngeal wash, but often produces false positives. Although quantitative real-time PCR is promising for discriminating colonization from PCP, the targeted DNA sequences and the cut-off values remain to be standardized. Serum β-D-glucan is useful as an adjunctive tool for the diagnosis of PCP. High-resolution computed tomography, which typically shows diffuse ground-glass opacities, is informative for evaluation of immunocompromised patients with suspected PCP and normal chest radiography.

EXPERT OPINION

Although these new tools have been making the diagnosis of PCP less invasive and more accurate, any one of them can not make a definitive diagnosis by itself. The diagnostic criteria based on the combination of the testing ought to be established.

Pneumocystis jiroveci pneumonia: high-resolution CT findings in patients with and without HIV infection

OBJECTIVE

The purpose of this essay is to review the spectrum of high-resolution CT findings of Pneumocystis jiroveci pneumonia in immunocompromised patients with and without HIV infection.

CONCLUSION

Pneumocystis jiroveci pneumonia is a common opportunistic infection affecting immunosuppressed patients. High-resolution CT may be indicated for evaluation of immunosuppressed patients with suspected pneumonia and normal chest radiographic findings. The most common high-resolution CT finding of Pneumocystis jiroveci pneumonia is diffuse ground-glass opacity. Consolidation, nodules, cysts, and spontaneous pneumothorax also can develop.

[Bacterial pneumonia in HIV-infected patients (excluding mycobacterial infection)]

Respiratory infections are the most common complications in HIV patients, regardless of the degree of immunosuppression. Even though antiretroviral therapy has a protective effect on the risk of bacterial pneumonia, this still remains high (including those with CD(4)>500/mm(3)). The most frequently isolated bacteria are Streptococcus pneumoniae and Haemophilus influenzae. The clinical and radiological presentations of lower respiratory tract infections in HIV patients are quite variable. The clinical presentation is more severe and the radiological presentation is more atypical if the immunosuppression is severe. The first-line antibiotic therapy is an injectable third-generation cephalosporin (ceftriaxone or cefotaxime) or co-amoxiclav. Pneumococcal vaccination (as well as influenza vaccine) is recommended. Although rare, Nocardia spp. and Rhodococcus equi seem more common among AIDS patients.

Swine-origin influenza A (H1N1) viral infection: thoracic findings on CT

OBJECTIVE

The purpose of this article is to illustrate and describe various CT manifestations of swine-origin influenza A (H1N1) viral infection.

CONCLUSION

The imaging findings seen in patients with H1N1 infection include consolidations, ground-glass opacities, interlobular septal thickening, small nodules, and findings suggestive of small airways disease, among others. Definitive diagnosis is based on correlation of the CT findings with the clinical symptoms and laboratory test results.

Undiagnosed AIDS in patients with progressive dyspnoea: an occupational risk for healthcare workers in Croatia

Pulmonary diseases are well documented and diverse in many patients with HIV in clinical stages 3 and 4. It is not unusual that these patients, most of whom do not know that they are already HIV-infected, are first examined and hospitalised by respiratory medicine specialists. While HIV-infection is relatively simple to diagnose if accompanied by advanced clinical manifestations and is regularly checked in patients with increased risk, this is not the case in low-risk patients, particularly in countries with low-level HIV epidemic and therefore low index of suspicion. Regular examination involves a series of tests, often including bronchoscopy with transbronchal lung biopsy in order to identify an interstitial lung disease and/or progressive dyspnoea. It is not uncommon that patients provide false or incomplete information about their lifestyle, which can mislead the clinician. At this point, HIV-infection is usually not suspected and healthcare workers may not strictly be following the safety principles which are otherwise applied when HIV-infection is known or suspect, although universal precautions are routine practice. At this point, the risk of exposure is the highest and HIV-transmission to healthcare workers is the most likely to occur. The cases presented here indicate that patients with progressive dyspnoea, which is typical of interstitial lung diseases, should undergo HIV-testing as a part of good clinical practice, even in a country with low-level HIV epidemic.

Pulmonary infections

This paper reviews the most common imaging findings of pulmonary infection in children. Pneumonia is a leading cause of mortality in children in developing and industrialized countries. While the imaging findings usually are nonspecific, correlation with the patient's age, immune status and pertinent history can limit the differential diagnoses. The paper will review the common and unique features of pneumonia caused by specific organisms and in specific patient populations.

Miliary tuberculosis: a comparison of CT findings in HIV-seropositive and HIV-seronegative patients

The aim of this study was to determine the differences in CT findings of miliary tuberculosis in patients with and without HIV infection. Two radiologists reviewed retrospectively the CT findings of 15 HIV-seropositive and 14 HIV-seronegative patients with miliary tuberculosis. The decisions on the findings were reached by consensus. Statistical analysis was performed using the chi2 test, Mann-Whitney U-test and Fisher's exact test. All of the HIV-seropositive and -seronegative patients had small nodules and micronodules distributed randomly throughout both lungs. HIV-seropositive patients had a higher prevalence of interlobular septal thickening (p = 0.017), necrotic lymph nodes (p = 0.005) and extrathoracic involvement (p = 0.040). The seropositive patients had a lower prevalence of large nodules (p = 0.031). In conclusion, recognition of the differences in the radiological findings between HIV-seropositive and -seronegative patients may help in the establishment of an earlier diagnosis of immune status in patients with miliary tuberculosis.

Pulmonary involvement in Kaposi sarcoma: correlation between imaging and pathology

Kaposi sarcoma is a low-grade mesenchymal tumor involving blood and lymphatic vessels. There are four variants of this disease, each presenting a different clinical manifestation: classic or sporadic, African or endemic, organ transplant-related or iatrogenic, and AIDS-related or epidemic. Kaposi sarcoma is the most common tumor among patients with HIV infection, occurring predominantly in homosexual or bisexual men. The pulmonary involvement in Kaposi sarcoma occurs commonly in critically immunosupressed patients who commonly have had preceding mucocutaneous or digestive involvement.

The etiology of Kaposi sarcoma is not precisely established; genetic, hormonal, and immune factors, as well as infectious agents, have all been implicated. There is evidence from epidemiologic, serologic, and molecular studies that Kaposi sarcoma is associated with human herpes virus type 8 infection. The disease starts as a reactive polyclonal angioproliferative response towards this virus, in which polyclonal cells change to form oligoclonal cell populations that expand and undergo malignant transformation.

The diagnosis of pulmonary involvement in Kaposi sarcoma usually can be made by a combination of clinical, radiographic, and laboratory findings, together with the results of bronchoscopy and transbronchial biopsy. Chest high-resolution computed tomography scans commonly reveal peribronchovascular and interlobular septal thickening, bilateral and symmetric ill-defined nodules in a peribronchovascular distribution, fissural nodularity, mediastinal adenopathies, and pleural effusions. Correlation between the high-resolution computed tomography findings and the pathology revealed by histopathological analysis demonstrate that the areas of central peribronchovascular infiltration represent tumor growth involving the bronchovascular bundles, with nodules corresponding to proliferations of neoplastic cells into the pulmonary parenchyma. The interlobular septal thickening may represent edema or tumor infiltration, and areas of ground-glass attenuation correspond to edema and the filling of air spaces with blood. These findings are a result of the propensity of Kaposi sarcoma to grow in the peribronchial and perivascular axial interstitial spaces, often as continuous sheets of tumor tissue.

In conclusion, radiological findings can play a major role in the diagnosis of pulmonary Kaposi sarcoma since characteristic patterns may be observed. The presence of these patterns in patients with AIDS is highly suggestive of Kaposi sarcoma.

Respiratory infections in immunocompromised patients

PURPOSE OF REVIEW

Immunosuppressive states and therapies are becoming common in clinical practice. Recent advances and trends in bacterial, fungal, viral and parasitic pulmonary infections in immunosuppressed patients are described.

RECENT FINDINGS

Pulmonary infections can jeopardize the prognosis of immunosuppressed patients. The number of patients infected with multidrug-resistant bacteria or opportunistic pathogens like rapid-growing environmental mycobacteria, Strongyloides stercoralis or Rhodococcus equi is increasing with the increased numbers of immunosuppressed patients due to HIV/AIDS and the potent immunosuppressive therapies used in solid-organ and haematopoietic transplantations, cancer and systemic illnesses. The slow development of more effective antibiotics underlines the necessity of preventive measures, development of rapid detection tests for pathogens and appropriate treatment regimens to avoid development of further resistance.

SUMMARY

Adequate prophylaxis, clinical suspicion, microbiological and molecular investigations, drug susceptibility-based antibiotic treatment and new drug development are strategies required to face up to the challenge of pulmonary infections in immunodepressed patients.

Pulmonary Kaposi sarcoma in a human immunodeficiency virus - infected woman: a case report

Approximately 90% to 95% of Kaposi sarcoma cases occur in human immunodeficiency virus – infected homosexual and bisexual men. Pulmonary Kaposi sarcoma is uncommon in women, and rarely considered as a potential cause of diffuse lung disease in women with acquired immunodeficiency syndrome. The disease is usually mistaken clinically for pulmonary infection. A 32-year-old woman was admitted with a 2-month history of dyspnea, evening fever, hemoptysis, weight loss, and generalized adenomegaly. Physical examination showed erythematous macules in the lower limbs. Skin and open lung biopsy demonstrated Kaposi sarcoma. Computerized tomography demonstrated peribronchovascular interstitial thickening. Although uncommon, pulmonary Kaposi sarcoma should be considered in the differential diagnosis of diffuse lung disease in women with AIDS.

Computed tomography for the diagnosis of infectious diseases of the chest

BACKGROUND

Pulmonary infection is a common reason for imaging of the lung in immunocompetent and immunosuppressed patients. Findings on chest radiography are nonspecific and encompass poor sensitivity. The role of computed tomography (CT) has been evolving in the diagnosis of lung infections.

OBJECTIVE

This paper reviews recent developments in the efficacy and utility of CT in the diagnosis of suspected pulmonary infections in a variety of patient populations.

METHODS

Recent published literature was reviewed to prepare this treatise on the role of CT.

CONCLUSION

Knowledge and skills at pattern recognition are crucial for the CT interpretation in lung infections. Computed tomography scan is increasingly used to increase the sensitivity of the radiologic diagnosis of thoracic infections. The greatest value of CT is when the radiograph is normal, findings are equivocal, and to differentiate infection from non-infectious disorders.

AIDS-related Kaposi sarcoma of the lung presenting with a "crazy-paving" pattern on high-resolution CT: imaging and pathologic findings

Kaposi sarcoma (KS) is a fulminate and disseminated form of acquired immunodeficiency syndrome (AIDS)-defining neoplasm, usually presenting pulmonary involvement. We report a 40-year-old woman with AIDS and biopsy-proven KS showing unusual high-resolution computed tomography (HRCT) findings. HRCT showed areas of ground-glass attenuation with superimposed septal thickening ("crazy-paving" pattern). CT-pathologic correlation revealed that crazy-paving pattern in this case was due to accompanying pulmonary edema and hemorrhage in addition to tumor cell infiltration into the peribronchovascular interstitium, interlobular and alveolar septa. The authors suggest the inclusion of KS in the differential diagnosis of lung diseases in patients with AIDS presenting with crazy-paving pattern on the HRCT.

Imagerie des pathologies thoraciques chez le patient VIH au stade sida

The imaging features of infectious and non-infectious pathologies in HIV patients with AIDS (less than 200 CD4/mm3) are illustrated. Opportunistic infections, tumors and vascular pathologies have variable appearances based on the degree of immunosuppression and patient compliance with opportunistic infection prophylaxis. Because of advances in retroviral treatments and wider use of anti-infectious prophylaxis, thoracic pathologies in AIDS patients are less frequent but must nonetheless be recognized, and diagnosis should be suggested in patients with unknown serologic status.

Pulmonary Paracoccidioidomycosis and AIDS

OBJECTIVE

To study the high-resolution computed tomographic (HRCT) findings in patients with AIDS and pulmonary paracoccidioidomycosis (PCM).

MATERIALS AND METHODS

The study included 5 consecutive patients (4 men and 1 woman, with ages ranging between 35 and 57 years; mean, 48 years) with diagnosis of AIDS and pulmonary PCM. All patients underwent HRCT, and the images were reviewed by 2 radiologists who reached decisions by consensus.

RESULTS

The predominant HRCT findings in the present series were large nodules (80%), cavited air-space consolidations (80%), ground-glass attenuation (80%), and cicatricial emphysema in the bases (80%). These lesions predominated bilaterally in the middle regions (80%) of the lungs.

CONCLUSIONS

The most common HRCT features in patients with AIDS and pulmonary PCM are large nodules associated with cavitated air-space consolidations and ground-glass attenuation, as well as cicatricial emphysema in the pulmonary bases. These findings are usually distributed bilaterally in the middle lung zones of the lungs.

Infecção pulmonar pelo Rhodococcus equi na síndrome da imunodeficiência adquirida: Aspectos na tomografia computadorizada

OBJETIVO: Apresentar os aspectos na tomografia computadorizada da pneumonia pelo Rhodococcus equi em sete pacientes com síndrome da imunodeficiência adquirida. MÉTODOS: Estudo retrospectivo das tomografias de sete pacientes com síndrome da imunodeficiência adquirida e infecção pelo Rhodococcus equi. RESULTADOS: Os achados mais freqüentes foram: consolidação (n = 7) com escavação (n = 6), opacidades em vidro fosco (n = 6), nódulos do espaço aéreo (n = 4) e nódulos centrolobulares com árvore em brotamento (n = 3). CONCLUSÃO: Os achados mais comuns na infecção pulmonar pelo Rhodococcus equi em pacientes com síndrome da imunodeficiência adquirida foram as consolidações escavadas.

Rhodococcus equi pneumonia in AIDS: high-resolution CT findings in five patients

The aim of this study was to describe the high-resolution CT scan findings in five patients with AIDS and pulmonary infection due to Rhodococcus equi. The study included five patients with AIDS and proven R. equi infection. The CT scans were reviewed by two observers. The patients included four men and one woman ranging from 39 years to 49 years in age (mean 42 years). The findings included areas of consolidation (n=5) with single (n=1) or multiple cavitation (n=4), ground-glass opacities (n=5), centrilobular nodules (n=3), small centrilobular nodular opacities (n=3) and "tree in bud" opacities (n=3). None of the patients had pleural effusion or lymph node enlargement. The most common high-resolution CT manifestations of R. equi infection consist of areas of consolidation with cavitation, ground-glass opacities, nodules and a tree-in-bud pattern.