Fungi are conditionally pathogenic and almost exclusively affect susceptible populations, especially immunodeficient individuals. In recent years, due to the widespread implementation of bone marrow stem cell and organ transplantation, the survival of patients with AIDS, AIDS, malignancies and severe diseases has increased, and the number of patients with immunodeficient survival has increased significantly. Therefore, it is especially important to identify fungal infections, especially those in the lungs, at an early stage with the proper use of comprehensive information from serology, pathogenesis and imaging. Respiratory fungal infections account for the first of all kinds of visceral fungal infections common pathogenic fungal diseases in China are Candida spp. Aspergillus spp. Cryptococcus spp. Conjugates and Pneumocystis spp. In recent years there are also some rare fungi such as Trichoderma spp. Pulmonary candidiasis is mostly seen in malignant blood disorders, acute leukemia and lymphoma, and in intravenous drug addicts. If the lesion involves only the bronchi, the symptoms are mild. In chronic cases, the onset is slow and the symptoms are atypical. This sign is non-specific X-ray chest radiographs with pathologic contrast reveal coagulative necrosis in the center of the nodules, surrounded by halo signs of edema and or hemorrhage [4] Diffuse cornea in both lungs Pathologically, the nodules are predominantly pulmonary alveolar solids, mainly parenchymal nodules without nodular lesions in the interlobular septa and pleura, with blurred margins 3 5 mm in diameter, but coarser and more sparse than the cornea nodules, which do not involve the lung apex. Histologically solid lesions are alveolar exudate and hemorrhage Some solid lesions represent alveolar edema Diffuse alveolar septal thickening or hyaline membrane CT shows a central lobular nodule A dendritic sign with a Y- or V-shaped peripheral lung appearance Glassy shadow A cavernous lesion can be seen in multiple bacterial infections or after a hemorrhagic pulmonary infarction We observed 38 cases of Candida albicans pneumonia in one group We observed 38 cases of Candida albicans pneumonia in one group. 17 cases had patchy solid lesions, 10 cases had nodular shadows, 2 cases had halo-like shadows, 3 cases each had tree-bud and bronchial inflation signs, and 2 cases had cavities. If the clinical symptoms worsen and/or the lung images show typical changes from mild to severe on top of the existing disease, the disease should be considered. Acute lesions with rapid short-term changes, cavities in the solid areas or fusion of pulmonary cornu foci suggest a poor prognosis. Since the clinical symptoms and imaging are not specific for this disease, pathogenic examination of the lesion tissue and blood culture are the only criteria to confirm the diagnosis. Aspergilloma allergic bronchopulmonary aspergillosis, ABPA chronic necrotizing pulmonary aspergillosis. aspergillus is the main pathogen of human pulmonary aspergillosis. The most common cause of Aspergillosis is tuberculosis or nodular disease. Aspergillus is often solitary, but can be bilateral. In combination with fungal infection, the cavity wall is thin, the inner wall is smooth, and the outer edge is indistinct. The detection rate of Mycobacterium tuberculosis in sputum is high, and it is easy to distinguish. Mucus inclusions mainly involve the upper lobe and subsegmental bronchi with high density and may have calcification ABPA needs to be differentiated from bronchial atresia and bronchiectasis but in combination with The diagnosis is usually not difficult when combined with the clinical features of the disease, imaging and laboratory tests related to Aspergillus. CNPA is often secondary to mild immunosuppression and has an insidious clinical presentation. The pathological changes are cavitation, bronchiectasis, pulmonary consolidation and fibrosis. The difference between IPA and bronchopneumonia is that it does not invade blood vessels and does not cause hematogenous dissemination. IPA occurs in patients with reduced immunity and is the most common opportunistic pulmonary fungal infection, often secondary to AIDS or in patients with malignant hematologic disease. Bronchiectasis and bronchiectasis may not show any abnormalities Bronchiectasis may appear as unilateral or bilateral patchy solid areas HRCT Bronchiectasis may appear as lobar central nodules Bronchiectasis may appear as unilateral or bilateral solid areas Lobar or segmental distribution of solid areas Can be fused Difficult to differentiate from tuberculosis or other viral infections and mycoplasma pneumonia Intravascular IPA pathology is the proliferation of mycelium in the airspace and The early manifestations of IPA are single or multiple nodules with indistinct margins in the peripheral and lower lobes of the lung. The incidence of cavitation in nodules or masses is about 40%, and the air crescent sign is often seen in the recovery phase. Lobulated, surrounded by a halo of ground glass B Pulmonary imaging shows a cavity in the left upper lung A round-like soft tissue shadow within the cavity Irregular pulmonary solidity and bronchiectasis are seen around the cavity Pleural thickening and a few fibrotic lesions in both upper lungs Pulmonary varices J Diagn Concepts Pract 2010, Vol. 9, No. 2. Edema and hemorrhage are associated with a lobar distribution of lesions [In the past 3 years, we collected 81 cases of IPA patients and analyzed their imaging data. 43 cases were found to have patchy or large invasive lesions in the lungs. 21 cases were found to have nodular lesions with a halo sign. 27 cases suggesting that the more characteristic varicellar perinodular halo sign, bronchiectasis and finger trap sign are less common in IPA. Pathogen testing is essential to effectively increase the detection rate and improve the prognosis of the patient. Pulmonary cryptococcosis Pulmonary is the primary route and second most susceptible organ for cryptococcal infection often associated with central nervous system infection Immunosuppressed patients such as AIDS are more susceptible Histologic response depends on immune status Patients with normal or near normal immune response usually present with limited pulmonary granulomatous response Severely immunosuppressed patients usually present with disseminated lesions Extensive infiltration of tissue by the pathogen Little to no tissue response Often involves central nervous system Most immunosuppressed patients with normal immune response are asymptomatic Severely immunosuppressed patients may have cough, fever, and shortness of breath Imaging is nonspecific and may show the following features Single or multiple nodular or mass nodules of variable size, well-defined borders, irregular shape, and may be lobulated and burrous See Figure 4 Nodules may be surrounded by glassy shadows that appear as halo signs Most are located in the outer lung zone and under the pleura Individual lesions can be difficult to distinguish from lung cancer Nodular or mass lesions alone are often seen in non-immunodeficient patients Younger patients are more likely to have cavities Reticular or reticular nodular interstitial manifestations with blurred margins Single or multiple lamellar infiltrative shadows with uneven densities Bronchial inflation signs may be present within them Some may have necrotic cavities See Figure 5 Glassy shadows Cornular nodular shadows The nodules were often multiple and could be fused into a mass, sometimes resembling grape clusters, and most of them occurred in the same lobe or subpleural lobe. The latex agglutination test for cryptococcal antigens in the cerebrospinal fluid has a positive rate of more than 92%, which is important for diagnosis. Pulmonary trichinosis Pulmonary trichinosis is rare and has a high mortality rate, occurring almost exclusively in immunocompromised patients. The lesion may also involve the bronchi and interstitium. Early imaging shows a single or multiple round-like lesion with no exact site of origin, poorly defined borders, and halo signs. Bronchial obstruction, halo signs and pseudoaneurysms that cannot be detected on chest radiographs The diagnosis of pulmonary bronchiectasis is confirmed by etiologic examination of the two lower lungs with multiple lamellar solid lesions surrounded by lamellar glassy shadows. Pulmonary bacillary mycosis is common in Canada or the Midwestern United States Pulmonary bacillary mycosis is a granulomatous pathology Pulmonary infections are rare The common sites of lesions are skin, bone, prostate, and central nervous system Imaging is varied Most often bronchopneumonia may show interstitial changes Pulmonary solids or limited masses Masses are often found in the mediastinum or parapneumonia Unlike histoplasma infections, this disease rarely affects the mediastinal lymph nodes and chest wall It is also rare to have a medium-sized nodular image, with a nodular diameter of 0.5 3 cm. The lesions may be unilateral or symmetrical, without a clear trend of lobar distribution. However, a careful analysis of the imaging manifestations combined with the underlying clinical disease and laboratory tests can mostly lead to a qualitative diagnosis and provide a reliable basis for clinical treatment.