Objective: This article reviews the anatomy, histology, and disease processes of pulmonary fissures, with emphasis on clinical implications of accessory and incomplete fissures. Conclusion: Accessory and incomplete pulmonary fissures are often overlooked during routine imaging but can have profound clinical importance. Knowledge of fissure anatomy could improve diagnostic accuracy and inform prognosis for oncologists, interventional pulmonologists, and thoracic surgeons.

OBJECTIVE The purposes of this article are to describe common and uncommon imaging signs and patterns of pulmonary infections and to discuss their underlying anatomic and pathophysiologic basis. CONCLUSION Imaging plays an integral role in the diagnosis and management of suspected pulmonary infections and may reveal useful signs on chest radiographs and CT scans. Detected early, these signs can often be used to predict the causative agent and pathophysiologic mechanism and possibly to optimize patient care.

OBJECTIVE:The purposes of this article are to describe common and uncommon imaging signs and patterns of pulmonary infections and to discuss their underlying anatomic and pathophysiologic basis. CONCLUSION:Imaging plays an integral role in the diagnosis and management of suspected pulmonary infections and may reveal useful signs on chest radiographs and CT scans. Detected early, these signs can often be used to predict the causative agent and pathophysiologic mechanism and possibly to optimize patient care.

OBJECTIVE:The Centers for Disease Control and Prevention reported more than one million people with HIV infection in the United States in 2006, an increase of 11% over 3 years. Worldwide, nearly 34 million people are infected with HIV. Pulmonary disease accounts for 30-40% of acute hospitalizations of HIV-infected patients, underscoring the importance of understanding the pulmonary manifestations in this population. When presented with a chest radiograph or CT image of a patient with the clinical history of HIV infection, one approach is to start by identifying and categorizing key imaging findings. In some instances, the key findings may be further subcategorized to narrow the differential diagnosis, such as distinguishing between perilymphatic distribution and the random distribution of micronodules. The differential diagnosis of these key imaging findings can also be further refined by incorporating clinical data, such as patient demographics, CD4 count, and presenting symptoms. Finally, the change of thoracic disease and clinical status in response to treatment provides important diagnostic information. The purpose of this article is to discuss pulmonary findings in patients with HIV.CONCLUSION:By developing a systematic and practical approach to key pulmonary imaging findings in HIV-infected patients, radiologists can generate clinically relevant and succinct differential diagnoses and thereby improve patient care.

OBJECTIVE:The Centers for Disease Control and Prevention reported more than one million people with HIV infection in the United States in 2006, an increase of 11% over 3 years. Worldwide, nearly 34 million people are infected with HIV. Pulmonary disease accounts for 30-40% of acute hospitalizations of HIV-seropositive patients, underscoring the importance of understanding the range of cardiothoracic imaging findings associated with HIV infection. This article will cover extrapulmonary thoracic diseases, chronic lung diseases, and immune reconstitution inflammatory syndrome in HIV-infected patients. Our approach is focused on the radiologist's perspective by recognizing and categorizing key imaging findings to generate a differential diagnosis. The differential diagnosis can be further refined by incorporating clinical data, such as patient demographics, CD4 count, and presenting symptoms. In addition, with prolonged survival of HIV-infected patients in the era of highly active antiretroviral therapy, radiologists can also benefit from awareness of imaging features of a myriad of chronic cardiopulmonary diseases in this patient population. Finally, the change of imaging findings and clinical status in response to treatment provides important diagnostic information, such as in immune reconstitution syndrome.CONCLUSION:Developing a practical approach to key cardiothoracic imaging findings in HIV-infected patients will aid the radiologist in generating a clinically relevant differential diagnosis and interpretation, thereby improving patient care.

Silicone, commonly used in cosmetic procedures owing to its presumed inertness, can yield serious sequelae including acute embolization and pneumonitis. Chronic pulmonary sequelae in response to silicone injection have not been previously described. We report a case of chronic progressive granulomatous pneumonitis in response to subcutaneous silicone injections in a transgender male-to-female patient infected with human immunodeficiency virus 1 (HIV-1). After receiving silicone injections to the buttock, the patient developed rapid onset dyspnea, pleuritic chest pain, fever, and chills. Chest computed tomography revealed diffuse peripheral interstitial opacities. She responded symptomatically to prednisone with subsequent intermittent symptomatic flares. Four years later, she developed marked dyspnea and cough. Chest computed tomography showed progressive diffuse ground-glass and nodular opacities. Lung biopsies demonstrated numerous spheroid silicone particles within the lung interstitium and small pulmonary vessels, surrounded by foreign body giant cells and nonnecrotizing granulomatous inflammation. We speculate that HIV-1-infected patients may be at risk for chronic, progressive granulomatous pneumonitis due to silicone injection years after their procedure owing to shifting levels of cell-mediated immunity.

Objectives To identify CT findings that predict mortality in acute respiratory distress syndrome (ARDS) and to identify CT findings that differentiate diffuse alveolar damage (DAD) from DAD with prominent histopathological features of organizing pneumonia (DAD-OP). Methods Twenty-eight patients with ARDS (corroborated by open biopsy) and chest CT within 2 weeks of biopsy were included in our study. Differences in CT findings in patients with survivors versus nonsurvivors as well as for DAD versus DAD-OP were compared using Fisher’s exact test. Results Lung involvement of greater than 80%, RA/LA ratio >1, and varicoid traction bronchiectasis were statistically more common in nonsurvivors than in survivors (respective p values of 0.001, 0.008, and 0.038). PA dilation greater than 3 cm and RV/LV ratio greater than 0.9 were also more common in nonsurvivors than in survivors but these factors did not achieve significance. CT findings did not differentiate DAD from DAD-OP. Conclusion Our study suggests that >80% of lung involvement, RA/LA ratio >1, and varicoid bronchiectasis predict mortality in patients with ARDS/DAD. Signs of right-sided heart failure (PA dilation greater than 3 cm and RV/LV ratio greater than 0.9) approached significance. CT findings did not differentiate DAD from DAD-OP.

Patients with preleukemic myeloid neoplasia can develop nonhematologic disease. Five patients with the myelodysplastic syndrome presented with interstitial lung disease that heralded acute leukemia in 3. Chest radiographs showed diffuse interstitial opacities, and the lung biopsies showed diffuse cellular interstitial and fibrosing pneumonitis with prominent alveolar filling by macrophages. There was no evidence to support a drug-induced or infectious etiology, and all cases lacked an identifiable leukemic infiltration. The inflammatory infiltrates and fibrosis were analyzed morphometrically, and this revealed a trend toward an indirect correlation between both CD68 cells and MPO-positive inflammatory cells and pulmonary fibrosis. We conclude that preleukemic myeloid neoplasia can be associated with an interstitial pneumonitis with histopathologic features that are distinguishable from both leukemic infiltration and "usual" nonspecific interstitial pneumonia.

This chapter discusses the pathology of the three major categories of pulmonary aspergillosis (invasive, allergic, and saprophytic) and the diagnostic imaging challenges they pose. The characteristic delayed (or transition) lesion of angio-invasive pulmonary aspergillosis occurs after partial recovery of neutrophil function, by which time the discrete nodule has begun to develop liquefaction necrosis limited to its periphery. Chronic IPA (CPA) is a incompletely understood, indolent but progressive Aspergillus infection that occurs in preformed or new cysts (or cavities). Allergic bronchopulmonary aspergillosis (ABPA) is the archetype of allergic aspergillosis. The clinical constellation of ABPA consists of chronic asthma, mucus production, and elevated serum antigen levels of Aspergillus fumigatus. Importantly, the asthmatic component and continuing lung damage are usually responsive to corticosteroid therapy. Corticosteroid-responsive ABPA-related asthma needs to be differentiated from simple chronic asthma. When patients with simple chronic asthma have bronchiectasis, it is usually of a mild variety and limited to the cylindrical type, i.e., bronchiectasis with parallel nontapering walls rather than with frank dilatation. Simple aspergilloma, or fungus ball, is the most common form of aspergillosis that is detected with imaging studies. A. fumigatus causes a wide variety of pulmonary diseases that result in significant morbidity and mortality. The clinical milieu helps identify the prior probability of such disease while the histopathology is predictive of the imaging findings.

PURPOSE The comparative cost-effectiveness of voriconazole and amphotericin B in the treatment of invasive pulmonary aspergillosis (IPA) was examined. METHODS A decision-tree model was constructed comparing 12-week treatment outcomes in a subset of patients enrolled in a clinical trial comparing initial treatment of IPA with amphotericin B versus voriconazole. Patients included those with IPA who underwent a thoracic computed tomographic (CT) scan at baseline. Cost and survival were estimated for those with and without a halo sign at baseline. Incremental cost-effectiveness ratios comparing voriconazole with amphotericin B were calculated for both patient subgroups. RESULTS Patients with a halo sign had similar costs and better survival rates than those without the sign. Within the subgroup of patients with the sign, total costs were lower and survival rates higher for those treated with voriconazole than for those treated with amphotericin B. For patients without a halo sign, total costs and survival rates were higher for those treated with voriconazole versus amphotericin B. CONCLUSION Among patients treated for IPA, those with a baseline CT halo sign, an early indicator of the condition, appeared to have better survival rates and lower health care costs compared with patients without the sign. In patients with the halo sign, survival rates were higher and costs were lower when voriconazole rather than amphotericin B was used as first-line treatment; survival was better with voriconazole than with amphotericin B when the halo sign was not present. Voriconazole was cost-effective compared with amphotericin B when the halo sign was present, but voriconazole's cost-effectiveness when the sign was not present depended on the cost per life saved.

BACKGROUND Invasive aspergillosis is an important cause of morbidity and mortality in immunocompromised patients. Current treatments provide limited benefit. Posaconazole is an extended-spectrum triazole with in vitro and in vivo activity against Aspergillus species. METHODS We investigated the efficacy and safety of posaconazole oral suspension (800 mg/day in divided doses) as monotherapy in an open-label, multicenter study in patients with invasive aspergillosis and other mycoses who were refractory to or intolerant of conventional antifungal therapy. Data from external control cases were collected retrospectively to provide a comparative reference group. RESULTS Cases of aspergillosis deemed evaluable by a blinded data review committee included 107 posaconazole recipients and 86 control subjects (modified intent-to-treat population). The populations were similar and balanced with regard to prespecified demographic and disease variables. The overall success rate (i.e., the data review committee-assessed global response at the end of treatment) was 42% for posaconazole recipients and 26% for control subjects (odds ratio, 4.06; 95% confidence interval, 1.50-11.04; P=.006). The differences in response between the modified intent-to-treat treatment groups were preserved across additional, prespecified subsets, including infection site (pulmonary or disseminated), hematological malignancy, hematopoietic stem cell transplantation, baseline neutropenia, and reason for enrollment (patient was refractory to or intolerant of previous antifungal therapy). An exposure-response relationship was suggested by pharmacokinetic analyses. CONCLUSIONS Although the study predates extensive use of echinocandins and voriconazole, these findings demonstrate that posaconazole is an alternative to salvage therapy for patients with invasive aspergillosis who are refractory to or intolerant of previous antifungal therapy.

BACKGROUND Computed tomography (CT) of the chest may be used to identify the halo sign, a macronodule surrounded by a perimeter of ground-glass opacity, which is an early sign of invasive pulmonary aspergillosis (IPA). This study analyzed chest CT findings at presentation from a large series of patients with IPA, to assess the prevalence of these imaging findings and to evaluate the clinical utility of the halo sign for early identification of this potentially life-threatening infection. METHODS Baseline chest CT imaging findings from 235 patients with IPA who participated in a previously published study were systematically analyzed. To evaluate the clinical utility of the halo sign for the early identification and treatment of IPA, we compared response to treatment and survival after 12 weeks of treatment in 143 patients who presented with a halo sign and in 79 patients with other imaging findings. RESULTS At presentation, most patients (94%) had > or =1 macronodules, and many (61%) also had halo signs. Other imaging findings at presentation, including consolidations (30%), infarct-shaped nodules (27%), cavitary lesions (20%), and air-crescent signs (10%), were less common. Patients presenting with a halo sign had significantly better responses to treatment (52% vs. 29%; P<.001) and greater survival to 84 days (71% vs. 53%; P<.01) than did patients who presented with other imaging findings. CONCLUSIONS Most patients presented with a halo sign and/or a macronodule in this large imaging study of IPA. Initiation of antifungal treatment on the basis of the identification of a halo sign by chest CT is associated with a significantly better response to treatment and improved survival.

Imaging findings in the pulmonary aspergilloses can answer important clinical questions. Steroid-responsive chronic asthma due to allergic bronchopulmonary aspergillosis can be differentiated from simple asthma by computed tomography (CT) evidence of extensive and severe central bronchiectasis, mucoid impaction, or small airways lesions. The simple aspergilloma can be differentiated from the complex aspergilloma by the absence of: constitutional symptoms, para-cystic lung opacities, cyst expansion, or progressive pleural thickening. The CT halo sign is a transient finding that can provide a probable diagnosis of early invasive pulmonary aspergillosis in patients who are at extraordinarily high risk of the infection. Patients with a halo sign at baseline are more likely to have a satisfactory treatment response than those without this indicator.

The role of clinical information and chest film for the discrimination between invasive pulmonary aspergillosis (IPA) and its differential diagnoses in human immunodeficiency virus (HIV) infection was studied. The diagnostic performance of clinical information and chest film alone and in combination was studied for eight internists and eight radiologists with regular exposure to IPA patients. The multicenter case sample consisted of 25 patients with proven IPA and 25 with other pulmonary diseases typical for HIV. The cases were presented on a CDROM. Receiver operating characteristics (ROC) methodology was employed. With clinical information alone, internists achieved the highest diagnostic performance (area under curve/AUC=0.84). Viewing the chest films did not contribute to their performance (AUC=0.80, P=0.26). The radiologist's performance on the basis of viewing the chest film (AUC=0.75) increased significantly (P=0.012) when clinical information (AUC=0.83) was supplied. IPA cases with characteristic radiological appearance were correctly identified in 90% with chest film. For radiologists with regular exposure to HIV patients, chest films hold relevant information and contribute to the determination in cases with characteristic radiological appearance. Overall and especially in cases with less characteristic radiological appearance, they have significant profit from full access to the clinical data. For internists with regular exposure to HIV patients, chest films do not provide information essential for the verification or differentiation of potential IPA.

In the evaluation of asbestos-related pulmonary and pleural abnormalities, conventional chest radiography has been shown to have a low sensitivity for the detection of lung nodules and subtle interstitial disease. Pleural plaques may simulate pulmonary nodules, and interstitial processes can be masked by adjacent pleural abnormalities. Dual-energy digital subtraction chest radiography may enable investigators to characterize asbestos-related pulmonary and pleural abnormalities with greater accuracy. “Soft-tissue” images, designed to remove pleural calcifications, may allow for better evaluation of the lung parenchyma. “Bone” images, designed to remove soft-tissue structures, may enhance the detection of pleural calcifications. In this pictorial essay we illustrate the methods, technical considerations, and limitations of dual-energy digital subtraction chest radiography performed with global subtraction weighting factors.