Imaging pulmonary infection: classic signs and patterns.

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.

What a differential a virus makes: a practical approach to thoracic imaging findings in the context of HIV infection--part 2, extrapulmonary findings, chronic lung disease, and immune reconstitution syndrome.

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.

What a differential a virus makes: a practical approach to thoracic imaging findings in the context of HIV infection--part 1, pulmonary findings.

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.

CT predictors of mortality in pathology confirmed ARDS.

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.

Accessory and Incomplete Lung Fissures: Clinical and Histopathologic Implications.

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.

Imaging findings in acute invasive pulmonary aspergillosis: clinical significance of the halo sign.

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.

Treatment of invasive aspergillosis with posaconazole in patients who are refractory to or intolerant of conventional therapy: an externally controlled trial.

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.

Voriconazole versus amphotericin B for primary therapy of invasive aspergillosis.

BACKGROUND: Voriconazole is a broad-spectrum triazole that is active against aspergillus species. We conducted a randomized trial to compare voriconazole with amphotericin B for primary therapy of invasive aspergillosis. METHODS: In this randomized, unblinded trial, patients received either intravenous voriconazole (two doses of 6 mg per kilogram of body weight on day 1, then 4 mg per kilogram twice daily for at least seven days) followed by 200 mg orally twice daily or intravenous amphotericin B deoxycholate (1 to 1.5 mg per kilogram per day). Other licensed antifungal treatments were allowed if the initial therapy failed or if the patient had an intolerance to the first drug used. A complete or partial response was considered to be a successful outcome. RESULTS: A total of 144 patients in the voriconazole group and 133 patients in the amphotericin B group with definite or probable aspergillosis received at least one dose of treatment. In most of the patients, the underlying condition was allogeneic hematopoietic-cell transplantation, acute leukemia, or other hematologic diseases. At week 12, there were successful outcomes in 52.8 percent of the patients in the voriconazole group (complete responses in 20.8 percent and partial responses in 31.9 percent) and 31.6 percent of those in the amphotericin B group (complete responses in 16.5 percent and partial responses in 15.0 percent; absolute difference, 21.2 percentage points; 95 percent confidence interval, 10.4 to 32.9). The survival rate at 12 weeks was 70.8 percent in the voriconazole group and 57.9 percent in the amphotericin B group (hazard ratio, 0.59; 95 percent confidence interval, 0.40 to 0.88). Voriconazole-treated patients had significantly fewer severe drug-related adverse events, but transient visual disturbances were common with voriconazole (occurring in 44.8 percent of patients). CONCLUSIONS: In patients with invasive aspergillosis, initial therapy with voriconazole led to better responses and improved survival and resulted in fewer severe side effects than the standard approach of initial therapy with amphotericin B.

Dual-energy digital subtraction chest radiography: technical considerations.

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.

Progressive granulomatous pneumonitis in response to cosmetic subcutaneous silicone injections in a patient with HIV-1 infection: case report and review of the literature.

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.

The impact of an early-morning radiologist work shift on the timeliness of communicating urgent imaging findings on portable chest radiography.

PURPOSE: The aim of this study was to assess the potential impact of staggered radiologist work shifts on the timeliness of communicating urgent imaging findings that are detected on portable overnight chest radiography of hospitalized patients. METHODS: The authors conducted a retrospective study that compared the interval between the acquisition and communication of urgent findings on portable overnight critical care chest radiography detected by an early-morning shift for radiologists (3 am to 11 am) with historical experience with a standard daytime shift (8 am to 5 pm) in the detection and communication of urgent findings in a similar patient population a year earlier. RESULTS: During a 4-month period, 6,448 portable chest radiographic studies were interpreted on the early-morning radiologist shift. Urgent findings requiring immediate communication were detected in 308 (4.8%) studies. The early-morning shift of radiologists, on average, communicated these findings 2 hours earlier compared with the historical control group (P < .001). CONCLUSION: Staggered radiologist work shifts that include an early-morning shift can improve the timeliness of reporting urgent findings on overnight portable chest radiography of hospitalized patients.

Spatial heterogeneity of lung perfusion assessed with (13)N PET as a vascular biomarker in chronic obstructive pulmonary disease.

UNLABELLED: Although it is known that structural and functional changes in the pulmonary vasculature and parenchyma occur in the progress of chronic obstructive pulmonary disease (COPD), information is limited on early regional perfusion (Q(r)) alterations. METHODS: We studied 6 patients with mild or moderate COPD and 9 healthy subjects (6 young and 3 age-matched). The PET (13)NN-labeled saline injection method was used to compute images of Q(r) and regional ventilation (V(r)). Transmission scans were used to assess regional density. We used the squared coefficient of variation to quantify Q(r) heterogeneity and length-scale analysis to quantify the contribution to total perfusion heterogeneity of regions ranging from less than 12 to more than 108 mm. RESULTS: Perfusion distribution in COPD subjects showed larger Q(r) heterogeneity, higher contribution from large length scales and lower contribution from small length scales, and larger heterogeneity of Q(r) normalized by tissue density than did healthy subjects. Dorsoventral gradients of V(r) were present in healthy subjects, with larger ventilation in dependent regions, whereas no gradient was present in COPD. Heterogeneity of ventilation-perfusion ratios was larger in COPD. CONCLUSION: Q(r) is significantly redistributed in COPD. Q(r) heterogeneity in COPD patients is greater than in healthy subjects, mainly because of the contribution of large lung regions and not because of changes in tissue density or V(r). The assessment of spatial heterogeneity of lung perfusion with (13)NN-saline PET may serve as a vascular biomarker in COPD.

Diffuse cellular and fibrosing interstitial pneumonitis with desquamative interstitial pneumonitis-like features associated with myeloid neoplasia.

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.

Comparative cost-effectiveness of voriconazole and amphotericin B in treatment of invasive pulmonary aspergillosis.

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.