Computer-assisted diagnosis for an early identification of lung cancer in chest X rays.

Computer-assisted diagnosis (CAD) algorithms have shown its usefulness for the identification of pulmonary nodules in chest x-rays, but its capability to diagnose lung cancer (LC) is unknown. A CAD algorithm for the identification of pulmonary nodules was created and used on a retrospective cohort of patients with x-rays performed in 2008 and not examined by a radiologist when obtained. X-rays were sorted according to the probability of pulmonary nodule, read by a radiologist and the evolution for the following three years was assessed. The CAD algorithm sorted 20,303 x-rays and defined four subgroups with 250 images each (percentiles ≥ 98, 66, 33 and 0). Fifty-eight pulmonary nodules were identified in the ≥ 98 percentile (23,2%), while only 64 were found in lower percentiles (8,5%) (p < 0.001). A pulmonary nodule was confirmed by the radiologist in 39 out of 173 patients in the high-probability group who had follow-up information (22.5%), and in 5 of them a LC was diagnosed with a delay of 11 months (12.8%). In one quarter of the chest x-rays considered as high-probability for pulmonary nodule by a CAD algorithm, the finding is confirmed and corresponds to an undiagnosed LC in one tenth of the cases.

Influence of using recommended radiological criteria on MDCT-angiography diagnosis of single isolated subsegmental pulmonary embolism.

OBJECTIVES: We assessed the rate of false-positive diagnoses of MDCT-pulmonary angiography (MDCT-A) in patients with single isolated subsegmental pulmonary embolism (SISSPE). METHODS: All patients who underwent MDCT-A between 2006 and 2017 for ruling out acute pulmonary embolism (PE) and received an initial diagnosis of SISSPE were included. The MDCT-A of these patients were reviewed retrospectively by four experienced thoracic radiologists, who applied radiological criteria recommended by the American College of Chest Physicians Antithrombotic Guidelines (ACCP 2016) for the diagnosis of SISSPE. Data extracted from medical records were history of venous thromboembolism (VTE), alternative diagnoses, other diagnostic studies for VTE, anticoagulation, bleeding complications, and VTE over the following 3 months. RESULTS: Of 3839 patients undergoing MDCT-A, PE was found in 1021 (26.6%) and SISSPE in 59 (1.5% overall and 5.8% of all patients with PE). An alternative diagnosis to PE was made on the basis of CT in 33 (55.9%) patients. Forty-one (69.5%) patients received anticoagulants, and major life-threatening bleeding complications occurred in 2, with one death. Recurrent PE was not documented in any patient with SISSPE. In the retrospective assessment of the 59 cases of SISSPE, 21 were negative for PE, with a false-positive rate of 35.6% (21/59); so the percentage of SISSPE cases after the revision was 3.7% of all patients with PE; 11 of these 21 patients received anticoagulation. CONCLUSIONS: Radiologists should be aware of the high rate of false-positives when making the diagnosis of SISSPE on MDCT-A without using strict diagnostic criteria. Misdiagnosis exposes patients to unnecessary anticoagulation. KEY POINTS: • Radiologist should be aware of the high rate of false-positive diagnoses of single isolated subsegmental pulmonary embolism (SISSPE) in MDCT-pulmonary angiography (MDCT-A) performed for ruling out pulmonary embolism. • Misdiagnosis of SISSPE in MDCT-A can be reduced by using strict diagnostic radiological criteria recommended by the American College of Chest Physicians Antithrombotic Guidelines. • Unnecessary anticoagulation therapy with potential severe bleeding complications may result from misdiagnosis of SISSPE.

Pseudomonas aeruginosa isolates in severe chronic obstructive pulmonary disease: characterization and risk factors.

BACKGROUND: Patients with severe chronic obstructive pulmonary disease (COPD) are at increased risk of infection by P. aeruginosa. The specific role of bronchiectasis in both infection and chronic colonization by this microorganism in COPD, however, remains ill defined.To evaluate the prevalence and risk factors for P. aeruginosa recovery from sputum in outpatients with severe COPD, characterizing P. aeruginosa isolates by pulsed-field gel electrophoresis (PFGE) and focusing on the influence of bronchiectasis on chronic colonization in these patients. METHODS: A case-cohort study of 118 patients with severe COPD attended at a Respiratory Day Unit for an acute infectious exacerbation and followed up over one year. High-resolution CT scans were performed during stability for bronchiectasis assessment and sputum cultures were obtained during exacerbation and stability in all patients. P. aeruginosa isolates were genotyped by PFGE. Determinants of the recovery of P. aeruginosa in sputum and chronic colonization by this microorganism were assessed by multivariate analysis. RESULTS: P. aeruginosa was isolated from 41 of the 118 patients studied (34.7%). Five of these 41 patients (12.2%) with P. aeruginosa recovery fulfilled criteria for chronic colonization. In the multivariate analysis, the extent of bronchiectasis (OR 9.8, 95% CI: 1.7 to 54.8) and the number of antibiotic courses (OR 1.7, 95% CI: 1.1 to 2.5) were independently associated with an increased risk of P. aeruginosa isolation. Chronic colonization was unrelated to the presence of bronchiectasis (p=0.75). In patients with chronic colonization the isolates of P. aeruginosa retrieved corresponded to the same clones during the follow-up, and most of the multidrug resistant isolates (19/21) were harbored by these patients. CONCLUSIONS: The main risk factors for P. aeruginosa isolation in severe COPD were the extent of bronchiectasis and exposure to antibiotics. Over 10% of these patients fulfilled criteria for chronic colonization by P. aeruginosa and showed clonal persistence, independently of the presence of bronchiectasis.

Imaging findings in pulmonary vasculitis.

Vasculitis is a destructive inflammatory process affecting blood vessels. Pulmonary vasculitis may develop secondary to other conditions or constitute a primary idiopathic disorder. Thoracic involvement is most common in primary idiopathic large-vessel vasculitides (Takayasu arteritis, giant cell arteritis, Behçet disease) and primary antineutrophil cytoplasmic autoantibody-associated small-vessel vasculitides (Wegener granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome). Primary pulmonary vasculitides are rare, and their signs and symptoms are nonspecific, overlapping with those of infections, connective tissue diseases, and malignancies. The radiologic findings in primary pulmonary vasculitis vary widely and can include vessel wall thickening, nodular or cavitary lesions, ground-glass opacities, and consolidations, among others. Diffuse alveolar hemorrhage usually results from primary small-vessel vasculitis in the lungs. To diagnose vasculitis, medical teams must recognize characteristic combinations of clinical, radiologic, laboratory, and histopathologic features.

When to suspect pulmonary vasculitis: radiologic and clinical clues.

Vasculitis is an inflammatory destructive process affecting blood vessels. Pulmonary vasculitis may be secondary to other conditions or constitute a primary, and in most cases idiopathic, disorder. Underlying conditions in the secondary vasculitides are infectious diseases, connective tissue diseases, malignancies, and hypersensitivity disorders. The most widely used approach to classifying the primary vasculitides is based on the size of the affected vessels (large, medium, small). Thoracic involvement is most commonly seen with primary idiopathic large-vessel vasculitides (Takayasu arteritis, giant cell arteritis, Behçet disease) and primary small-vessel antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitides (Wegener granulomatosis, microscopic polyangiitis, Churg-Strauss syndrome). The radiologic manifestations of primary pulmonary vasculitis are extremely variable and include vessel wall thickening, nodular or cavitary lesions, ground-glass opacities, and consolidations. Diffuse alveolar hemorrhage is a clinical syndrome that usually results from primary small-vessel vasculitis in the lungs. Although chest radiography is often the first imaging study performed in patients with pulmonary involvement by vasculitis, chest radiographs often fail to show the exact pattern and extent of thoracic involvement and CT is more useful in assessment of the thoracic findings. The pulmonary primary vasculitides are rare disorders, and their diagnoses are among the most demanding challenges in medicine because their signs and symptoms are nonspecific and overlap with those of infections, connective tissue diseases, and malignancies; thus, diagnosis of vasculitis relies on recognition of characteristic combinations of particular clinical, radiologic, laboratory, and histopathologic features.

Multidetector computed tomography findings of dense pulmonary emboli in oncologic patients.

Pulmonary embolism is a frequent condition for which multidetector computed tomography (MDCT) plays an important role in its detection. Occasionally, on MDCT studies, dense linear branching opacities may be found within the pulmonary vessels. They represent dense emboli within the pulmonary arteries (DEPA). These may occur in oncologic patients that undergo specific treatments or interventional procedures, such as cement embolus from vertebroplasty, catheter or coil migration after embolization procedures, radioactive seed embolus in patients treated with local brachytherapy for prostate, lung, or liver cancer, and also in chronic pulmonary embolism. Usually DEPA does not have any clinical significance but may be fatal when massive or when in patients with impaired cardiopulmonary function. Being familiar with their radiologic appearance and knowing about the good clinical outcome of these patients will avoid unnecessary imaging testing. In this article, we describe some examples of DEPA. Based on the MDCT imaging findings, these emboli have very few or no side effects on the underlying lung parenchyma. We would like to stress the need for using bone window values for identifying these emboli. We provide examples of dense linear nonvascular images (pulmonary calcification secondary to tuberculosis (TBC) or radiotherapy, calcified mucous plugs, lung sutures, etc) that may mimic DEPA.

CT diagnosis of chronic pulmonary thromboembolism.

Chronic pulmonary thromboembolism is mainly a consequence of incomplete resolution of pulmonary thromboembolism. Increased vascular resistance due to obstruction of the vascular bed leads to pulmonary hypertension. Chronic thromboembolic pulmonary hypertension is clearly more common than previously was thought, and misdiagnosis is common because patients often present with nonspecific symptoms related to pulmonary hypertension. Computed tomography (CT) is a useful alternative to conventional angiography not only for diagnosing chronic pulmonary thromboembolism but also for determining which cases are treatable with surgery and confirming technical success postoperatively. The vascular CT signs include direct pulmonary artery signs (complete obstruction, partial obstruction, eccentric thrombus, calcified thrombus, bands, webs, poststenotic dilatation), signs related to pulmonary hypertension (enlargement of main pulmonary arteries, atherosclerotic calcification, tortuous vessels, right ventricular enlargement, hypertrophy), and signs of systemic collateral supply (enlargement of bronchial and nonbronchial systemic arteries). The parenchymal signs include scars, a mosaic perfusion pattern, focal ground-glass opacities, and bronchial anomalies. The presence of one or more of these radiologic signs arouses suspicion and allows diagnosis of this entity. Early recognition of chronic pulmonary thromboembolism may help improve the outcome, since the condition is potentially curable with pulmonary thromboendarterectomy.

Primary pericardial mesothelioma.

Primary pericardial mesothelioma is a rare clinical entity; about 150 cases have been described in literature. It is a highly aggressive tumour with global survival under 6 months. We present a 44-year-old man with a primary pericardial mesothelioma who received treatment under clinical essay with carboplatinum and pemetrexed reaching tumoral response; consolidation radiotherapy was administered. Ten months after end of radiotherapy, tumoral progression was detected, and patient received second line of chemotherapy. The patient died 16 months after diagnosis. New cytotoxic drugs can improve the prognosis of this rare entity.

Nodular pattern at lung computed tomography in fat embolism syndrome: a helpful finding.

The purpose of this study is to describe the computed tomography (CT) findings in pulmonary fat embolism syndrome (FES). The chest radiographs and CT scans of 5 patients with the diagnosis of FES as determined by the presence of at least 1 major and 4 minor criteria were reviewed. The radiologic features included ground-glass opacities, with different patterns of presentation seen in all patients. Three patients presented with alveolar opacities, and small (<1 cm) ill-defined nodules were seen in 4 of 5 patients. In the context of a patient with previous trauma and the clinical suspicion of FES, the presence of nodules at CT examination may be a helpful finding in the diagnosis of this entity. The chest radiographs and CT scans of 5 patients with the diagnosis of FES as determined by the presence of at least 1 major and 4 minor criteria as defined by Gurd and Wilson were reviewed.

Congenital and acquired pulmonary artery anomalies in the adult: radiologic overview.

Various congenital and acquired anomalies may affect the pulmonary arteries in adult patients. Congenital anomalies (proximal interruption, anomalous origin of the left pulmonary artery [pulmonary artery sling], and idiopathic dilatation of the pulmonary trunk) are usually found incidentally at chest radiography or computed tomography (CT). Acquired anomalies include diffuse or focal enlargement of the arteries because of pulmonary hypertension, aneurysm, and intravascular pulmonary metastasis; decreased arterial diameter because of bronchial carcinoma, mediastinal fibrosis, and Takayasu arteritis; and intraluminal filling defects due to pulmonary thromboembolism and pulmonary artery sarcoma. An awareness of the radiologic manifestations of the disease entities and potential pulmonary artery complications secondary to infection or vasculitis may enable an early diagnosis. CT angiography is becoming the standard method for evaluating patients in whom the presence of pulmonary embolism is suspected. CT assessment of the extent of heart effects in patients with pulmonary hypertension and pulmonary embolism is particularly important because such effects largely determine the prognosis.

Diseases affecting the peribronchovascular interstitium: CT findings and pathologic correlation.

Central bronchi and pulmonary arteries are surrounded and enveloped by a strong connective-tissue sheath termed the peribronchovascular interstitium, extending from the level of the pulmonary hila into the peripheral lung. Thickening of the peribronchovascular interstitium can be seen in a wide variety of diseases. The CT appearance can be smooth, nodular, or irregular depending on the underlying cause. Many of the diseases affecting the peribronchovascular interstitium are entities that show a predilection for lymphatic routes, such as sarcoidosis, pulmonary lymphangitic carcinomatosis, silicosis, and lymphoproliferative disorders. There are other entities that mainly affect the peribronchovascular interstitium without a predominant perilymphatic distribution, such as hydrostatic pulmonary edema, cryptogenic organizing pneumonia, Kaposi's sarcoma, interstitial pulmonary emphysema, and interstitial hemorrhage. Although there is an overlap in radiologic features, some CT findings are useful in differentiating among these entities. When CT shows mainly peribronchovascular abnormality, the differential diagnosis is considerably reduced, and it is generally possible to reach the correct diagnosis by considering the clinical context. We illustrate the CT findings and pathologic correlation for a number of different disorders that mainly affect the peribronchovascular interstitium.

Radiologic approach to the diagnosis of infectious pulmonary diseases in patients infected with the human immunodeficiency virus.

Nearly all patients infected with HIV experience respiratory infection at some point in the course of their illness. The spectrum of infections is varied and in order to generate a useful differential diagnosis based on imaging findings it is imperative for the radiologist to be aware of changing trends in disease prevalence and epidemiology, and the possible pathology related to new therapies. The characterization of the radiographic pattern in correlation with clinical findings and laboratory values (in particular the degree of immunosuppression as reflected in the CD4 level) would be helpful in narrowing the differential diagnosis of infectious pulmonary disease in HIV-positive patients. The most common radiologic patterns considered include areas of ground-glass, consolidation, nodules, and lymphadenopathy. We also include airways diseases and cavitary/cystic lesions because their prevalence has increased over recent years, and we also mention the significance of a normal chest radiograph in the suspicion of a lung infection. In most cases, the clinical and radiographic findings are sufficient for confident diagnosis. The radiologic diagnosis of thoracic infections in patients with AIDS has improved with the use of CT. The greatest value of CT is in excluding lung disease when the radiographic findings are equivocal and in confirming the presence of clinically suspected disease when the radiograph is normal.

CT in nontraumatic acute thoracic aortic disease: typical and atypical features and complications.

Thoracic aortic dissection is the most frequent cause of aortic emergency, and unless it is rapidly diagnosed and treated, the result is death. Helical computed tomography (CT) permits the diagnosis of acute aortic dissection with a sensitivity and specificity of nearly 100%. This imaging modality also enables differentiation between proximal aortic dissection (type A in the Stanford classification) and distal aortic dissection (Stanford type B), which are treated differently and have different prognoses. In 70% of patients in whom nontraumatic acute thoracic aortic dissection is diagnosed after evaluation with helical CT, scans show the typical signs of aortic dissection, with rupture and displacement of the intima. CT also can depict other pathologic entities with similar clinical manifestations, such as intramural hematoma and penetrating atherosclerotic ulcer. Awareness of the different radiologic appearances of these disease entities is essential for differential diagnosis. More than one-third of patients with aortic dissection show signs and symptoms indicative of systemic involvement. Because branch-vessel involvement may increase morbidity and mortality, in this group of patients it is important to evaluate the entire aorta so as to determine the distal extent of the dissection and detect any systemic involvement.