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    Home > Active Ingredient News > Infection > Professor Li Hongjun: Current status and progress of imaging diagnosis of hematological diseases and lung infections

    Professor Li Hongjun: Current status and progress of imaging diagnosis of hematological diseases and lung infections

    • Last Update: 2021-04-18
    • Source: Internet
    • Author: User
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    Pulmonary infection is a common infectious complication in the clinical treatment of hematological diseases.
    With the application of high-dose chemotherapeutics such as hormones and immunosuppressants, the incidence of pulmonary infection in patients with hematological diseases has increased significantly.

    Among them, imaging plays a very crucial role in the rapid diagnosis and evaluation of lung infections.

    Professor Li Hongjun from Beijing You'an Hospital affiliated to Capital Medical University shared the "Current Status and Progress of Imaging Diagnosis of Blood Diseases and Lung Infections".

    Overview of respiratory tract infections in patients with hematological tumors Professor Li Hongjun emphasized that we must pay attention to the risk of respiratory tract infections in patients with hematological tumors.

    Patients with hematological tumors usually need to receive high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT) treatment, and these treatment methods combined with the disease itself will lead to immunosuppression in patients, and about 50% of patients with hematological tumors will develop respiratory tract during treatment.
    infection.

    However, the incidence of non-infectious diseases after HSCT is about half of respiratory complications, and the treatment of non-infectious diseases usually requires increased immunosuppression.
    Therefore, before starting the treatment of non-infectious lung complications of hematological tumors , It is necessary to exclude infectious complications in order to ensure the precise treatment effect.

    1.
    Non-infectious respiratory complications of immunosuppressed patients Professor Li Hongjun said that non-infectious respiratory complications of immunosuppressed patients can be divided into different clinical manifestations.

    According to its clinical characteristics, it can be divided into: acute manifestations (a few hours to several days): pulmonary edema, acute respiratory distress syndrome, diffuse alveolar hemorrhage, implantation syndrome, etc.
    ; subacute manifestations (a few days to several weeks): special Primary pneumonia syndrome, organizing pneumonia, radiation pneumonia, and drug toxicity; chronic manifestations (weeks to months): pulmonary vein occlusion, lung graft versus host disease, pleuropulmonary elastofibrosis, etc.Professor Li Hongjun mentioned that different clinical manifestations represent different pathological characteristics, and pathology is the basis of imaging, and imaging is the external manifestation of pathology.
    The two are inseparable.

    Therefore, the imaging diagnosis should be based on clinical staging and diagnosis based on pathogens and pathological features.

    2.
    Sources of pathogens that cause respiratory infections Professor Li Hongjun said that pathogens that cause respiratory infections mainly come from the following aspects: enter the lungs from various sources: common gram-positive pathogens and gram-negative pathogens, such as gold Staphylococcus aureus, Pseudomonas aeruginosa, anaerobic bacteria, etc.
    ; spread by droplet inhalation: mainly including common respiratory viruses, uncommon Mycoplasma pneumoniae, Chlamydia pneumoniae and Mycobacterium tuberculosis, as well as those that do not cause immunity Host infection of aspergillus, non-tuberculous mycobacteria, etc.
    ; reactivation of original pathogens: Pneumocystis pneumonia (PJP), cytomegalovirus (CMV) and other type I herpes simplex virus (HERP), etc.
    ; blood sexual transmission: For example, Candida and bacteria can be spread to the lungs through indwelling catheters and catheters.

    Distinguishing infectious and non-infectious lung complications Professor Li Hongjun said that the pulmonary complications of HSCT reflect the patient’s immune status, which can be divided into three stages: ① Neutropenia period (to 3 weeks after transplantation) ): Characterized by bacterial infections and fungal infections.
    Gram-negative bacteria and Gram-positive bacteria are the main pathogens of bacterial infections.
    The most common causes of fungal pneumonia are aspergillus, mucormycin and candida.

    Non-infectious complications include alveolar hemorrhage, pulmonary edema, and drug reactions.

    Professor Li Hongjun mentioned that, unlike fungal infections, non-infectious complications at this stage often manifest as diffuse diseases.

    Left image: bilateral patchy ground glass shadow in patients with diffuse alveolar hemorrhage; right image: thickened interlobular septum, ground glass shadow and pleural effusion in patients with pulmonary edema ②Early (3 weeks to 100 days): appearing in this period Non-infectious complications are mainly idiopathic pneumonia syndrome, which is defined as diffuse lung injury after HSCT.
    If there is no evidence of infection, the diagnosis is exclusionary.

    Diffuse alveolar damage ③ Late stage (100 days after transplantation): It is characterized by bronchiolitis obliterans, cryptogenic organizing pneumonia, and chronic graft-versus-host disease.

    Left image: Patients with cryptogenic organizing pneumonia have anti-halo signs; Right image: Post-transplant lymphoproliferative patients, CT shows multiple nodules with bronchial inflation signs (arrows).
    Epidemiology and imaging of invasive fungal infections Feature Professor Li Hongjun said that although the incidence of invasive fungal infection (IFI) has declined in the past decade, the mortality rate remains high.

    Epidemiological studies in recent years have shown that the incidence of Candida is on the decline, and the incidence of aspergillosis is on the rise.

    1.
    CT imaging features of IFI-nodules and halo signs Professor Li Hongjun showed the CT results of a 27-year-old male patient with chronic myeloid leukemia and invasive aspergillosis.

    Large nodules with halo sign 2.
    CT image features of IFI-anti-halo sign Next, Professor Li Hongjun shared a CT image of a case of anti-halo sign.
    The patient was infected with mucor and showed consolidation of the middle and lower lobes of the right lung.
    The shadow, located under the pleura, shows cavities and anti-halo signs in the consolidation.

    Cavity and anti-halo sign 3.
    CT imaging characteristics of IFI-low density sign In addition, Professor Li Hongjun also showed a 63-year-old patient with aplastic fever after acute leukemia bone marrow transplantation, whose lung CT showed pulmonary nodules Low density sign.

    CT imaging shows low-density pulmonary nodules.
    4.
    CT imaging features of IFI-air crescent sign.
    The picture below shows a CT image of a patient with hematological disease and invasive pulmonary aspergillosis, showing a cavity or cavity in the lung A crescent-shaped translucent shadow is formed between the spherical lesion and the cave wall.

    The epidemiological and imaging features of Air Crescent PJP, Professor Li Hongjun mentioned that among patients receiving preventive treatment, the incidence of PJP is as low as 0.
    1%.

    However, mixed lung infections are common, especially cytomegalovirus infections.

    In CT examination, almost all patients with PJP have the typical manifestations of diffuse bilateral ground-glass shadows, and extensive ground-glass shadows are usually distributed around the hilar.

    The presence of mosaic sign is an indicator (P<0.
    001; OR=9.
    808; 95%CI=4.
    883-19.
    699), and the sensitivity, specificity, positive predictive value and negative predictive value are 65.
    7%, 88.
    3%, 71.
    1% and 85.
    5%. In addition, the absence of nodules is also a meaningful indicator (P<0.
    001; OR=6.
    834; 95%CI=3.
    438-13.
    587), with sensitivity, specificity, positive predictive value and negative predictive value of 79.
    0% and 70.
    8%, respectively , 54.
    2% and 88.
    5%.

    Two-sided ground glass shadows, mosaic signs (arrows) and epidemiological characteristics and imaging features of the reticulated virus, Professor Li Hongjun analyzed the virus infection and treatment of patients with HSCT or hematological tumors.

    The incidence of viral infection, pneumonia, mortality and treatment of HSCT or hematological tumor patients Professor Li Hongjun said that due to preventive treatment, the current incidence of cytomegalovirus pneumonia (CMVP) is in the early post-transplantation period (post-transplantation).
    100 days) is only 1~3%, and within the first year after transplantation, the probability of a patient developing CMVP is 1~8%.

    The most common imaging feature of CMVP is bilateral lung interstitial infiltration on X-ray films, and some patients may not have local X-ray signs.

    The most common CT manifestations are bilateral asymmetric ground glass shadows (patchy or diffuse), air cavity consolidation, small nodules in the center of the lobules, pleural effusions, and lesser manifestations of nodules (may be accompanied by dizziness) Sign) or lung consolidation.

    Left: small nodular shadows (arrows) in the center of the lobules, accompanied by fine meshes; right: epidemiological and imaging features of patchy infiltrating bacterial pneumonia composed of ground glass shadows and consolidation Li Hongjun The professor said that most patients (50%) developed bacterial pneumonia in the late post-transplantation period, while the pre-implantation and early post-implantation rates were 26.
    7% and 23.
    3%, respectively.

    The imaging characteristics of patients with bacterial pneumonia are generally ground glass shadows, nodules, consolidation, bronchial wall thickening, cavities and other conditions.
    Therefore, it is often difficult to correctly determine the cause of pneumonia and what kind of pathogen infection on the image.

    Left picture: air cavity consolidation; right picture: summary of ground glass shadow, consolidation and bronchial wall thickening.
    Finally, Professor Li Hongjun concluded that after induction chemotherapy or HSCT treatment in patients with blood diseases, their immunity is low and they are susceptible to infection with various pathogens .

    However, invasive testing is usually not feasible for patients with severe thrombocytopenia and neutropenia.

    In addition, laboratory tests also have certain limitations.

    However, imaging examination can assist in the clinical diagnosis of infectious pulmonary complications, and the future imaging technology based on imaging immunology will provide a more sensitive and non-invasive method for clinical diagnosis and treatment, and will provide better services for clinical diagnosis and treatment.
    .

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