Respiratory tract

Aspiration pneumonia

Mycobacterium tuberculosis pneumonia

Staphylococcus pneumonia

Secondary pulmonary nodule disease

Differentials

Cystic lung lesions

Lower zone lung disease

Upper zone lung disease

Extramedullary hematopoiesis

Compensatory mechanism to increase bone marrow function Seen in thalassemia, hereditary spherocytosis, sickle cell anemia Typically in lower thorax Symmetrical, bilateral Marrow bursts out of bone and appears as soft tissue mass May have fatty content within

Lateral thoracic meningocele

Rare Redundant spinal meninges protrudes through intervertebral foramen Contains CSF Asymptomatic Difficult to distinguish from neurogenic tumors

Congenital venolobar syndrome

Scimitar syndrome Lung hypoplasia and ipsilateral anomalous systemic venous drainage Anomalous right pulmonary vein drains into IVC, hepatic or portal vein, coronary sinus or right atrium Most asymptomatic Left-to-right shunt  can lead to pulmonary hypertension Imaging Similar to isolated lung hypoplasia – increased opacity of one hemithorax, mediastinal shift, contralateral lung hyperinflation Anomalous vein –…

Congenital lobar hyperinflation

Bronchial abnormality Check-valve mechanism, causes progressive hyperinflation of affected lobe Tends to reduce with time in asymptomatic patients Needs excision in symptomatic children Imaging Left upper lobe (42%) Right middle lobe (35%) Radioopacity in affected lobe in postnatal period due to fluid With time, hyperinflation with hyperlucency of affected lobe CT: rules out other causes…

Idiopathic pulmonary hemosiderosis

Rare, unknown etiology Children 0-10 years Episodic intra-alveolar hemorrhage Hemoptysis Iron-deficiency anemia Airspace opacities on plain film Repetitive bleeding leads to lung fibrosis Read more Saeed, Muhammad M., et al. “Prognosis in pediatric idiopathic pulmonary hemosiderosis.” Chest 116.3 (1999): 721-725.

Granulomatous polyangiitis

Earlier called Wegener’s granulomatosis Primary (idiopathic) small vessel vasculitides Necrotizing granulomatous inflammation of small vessels of upper and lower respiratory tract M=F Any age of presentation Lungs affected in 90% of cases Cough, dyspnea, pleuritic chest pain, hemoptysis c-ANCA directed against proteinase-3 is positive Imaging Chest Xray Bilateral nodules or masses Nodules from few mm…

Chronic eosinophilic pneumonia

Protracted course More symptomatic Mild to moderate eosinophilia Elevated serum IgE in peripheral blood Good prognosis Patients respond to steroids Imaging Chest Xray Patchy non-segmental consolidation Involves mid and upper zones Opacities peripheral and parallel to chest wall – photographic negative of pulmonary edema CT Same findings as plain film, more apparent in CT Differential:…

Alveolar proteinosis

Accumulation of periodic acid Schiff positive lipoproteinaceous material in alveoli Due to abnormal surfactant clearance from lungs Fault in GM-CSF signaling  Primary – idiopathic due to anti GM-CSF antibodies Secondary – dust inhalation, infections, myelodysplasia, lymphoma, myeloid leukemia 20-50 years  M>F More in children Definitive diagnosis: bronchoalveolar lavage, biopsy Imaging Chest Xray Nonspecific Both lungs…

Alveolar microlithiasis

Deposition of tiny stones mainly made of calcium phosphate in air spaces Mutations in SLC34A2 gene. This gene codes for sodium dependent phosphate transporter in type II alveolar cells Causes phosphate accumulation 30-50 years age Asymptomatic at presentation Imaging Chest Xray Widespread discrete high density opacities (resembling sand grains) When profusely involving lungs, similar to…

Simple pulmonary eosinophilia

Loffler’s syndrome Elevated eosinophil count in peripheral blood Association with parasitic infection – Ascaris lumbricoides Imaging Chest Xray Fleeting transient infiltrates Uni or bilateral Resolution of opacities within days and maximum one month CT Ground-glass opacities, consolidation Periphery of mid and upper lung zones Single or multiple acinar nodules Read more Jeong, Yeon Joo, et…

Limitations of portable chest radiography

Scattered radiation Inability to capture all relevant information Significant underexposure increases noise and reduces contrast resolution Shorter focus-detector distance causes undesirable magnification High kV techniques not possible, longer exposure times needed, hence more motion artifacts

Pleural effusion in children

Causes  Infection  Parapneumonic  Empyema – streptococcal or staphylococcal  Tuberculosis   Neoplasm  Leukemia  Lymphoma  Metastasis: Wilms  PNET  Mesothelioma  Inflammatory   Pancreatitis (small, left)  Fluid overload  Low albumin states  Cardiac failure  Severe sepsis  Trauma  Hemothorax   Congenital   Diaphragmatic hernia  Chylothorax – lymphangiectasia / lymphangiomatosis 

One year post COVID chest imaging

CT patterns of viral pneumonia

Bilateral symmetrical elevation of diaphragm

supine position poor inspiration obesity pregnancy abdominal distension (ascites, intestinal obstruction, abdominal mass) diffuse pulmonary fibrosis lymphangitis carcinomatosa disseminated lupus erythematosus bilateral basal pulmonary emboli painful conditions (after abdominal surgery) bilateral diaphragmatic paralysis

Unilateral elevation of diaphragm

posture – lateral decubitus position (dependent side) gaseous dissension of stomach or colon dorsal scoliosis pulmonary hypoplasia pulmonary collapse phrenic nerve palsy eventration pneumonia or pleurisy pulmonary thromboembolism rib fracture subphrenic infection subphrenic mass

Lines and tubes in neonates

endotracheal tube tip varies with head and neck motion tip should be above carina consider chin position nasogastric tube within stomach nasojejunal tube include weighted tip side hole at duodenojejunal flexure umbilical arterial line tip between T6 and T9 course inferiorly within umbilical artery into internal and common iliac arteries, then into aorta umbilical venous…

Neonatal pneumonia

occurs perinatally ascending infection from vagina transvaginally during birth hospital acquired infection in post natal period prolonged rupture of membranes is a known risk infant swallows or aspirates infected amniotic fluid or vaginal tract secretions Group B streptococcus most common organism imaging severe acute symptoms first 24-48 hours coarse bilateral asymmetrical alveolar opacification with or…

Transient tachypnea of the newborn

retained fetal lung fluid / wet-lung syndrome normally fluid cleared from lungs at or immediately after birth by pulmonary lymphatics and capillaries normal clearance delayed in this condition seen post caesarean section, hypoproteinemia, hyponatremia, maternal fluid overload seen in small hypotonic sedated infants with precipitous delivery mild to moderate respiratory distress without cyanosis in first…

Idiopathic respiratory distress syndrome

hyaline membrane disease affects premature infant < 36 weeks deficiency of lipoprotein pulmonary surfactant and structural immaturity of lungs pathophysiology lipoproteins produced by type II pneumocytes concentrated in cell lamellar bodies then transported to cell surface and expressed on alveolar luminal surface lipoproteins combine with surface surfactant proteins A, B, C and D to form…

Normal lung development

26 days to 6 weeks (embryonic phase) lung bud develops from primitive foregut bud divides to form early tracheobronchial tree 6 to 16 weeks (pseudoglandular phase) airway development up to terminal bronchioles deficient alveolar saccules 16 to 28 weeks (canalicular or acinar phase) multiple alveolar ducts develop from respiratory bronchioles ducts lined by type II…

Neonate chest

AP and transverse diameter equal, giving a cylindrical configuration rotation assessed by comparing length of anterior ribs normal cardiothoracic ratio up to 0.6 variable thymic size thymic involution: prenatal or postnatal stress, hyaline membrane disease, corticosteroid treatment known artefacts: hole in incubator top looks like pneumatocele. skin fold mimic pneumothorax

Imaging pleural effusion

chest radiograph small subpulmonary effusions not seen minimal fluid best detected in lateral decubitus radiograph 200 to 500 ml fluid needed for blunting of posterior and lateral costophrenic angles homogenous opacification of lower chest obliteration of costophrenic angle and hemidiaphragm superior margin of opacity concave to lung and higher laterally than medially above and medial…

Pleural effusion

Types of effusion transudate exudate (thin or thick) blood chyle bile CSF iatrogenic fluids Bilateral pleural effusion tend to be transudates due to rise in capillary pressure or fall in blood proteins exudative bilateral effusion: metastasis, lymphoma, pulmonary embolism, rheumatoid disease, SLE, post-cardiac injury syndrome, myxedema and some ascites related effusions Right sided effusions ascites…

Azygos fissure

How to pick pleural effusion on a chest Xray