Respiratory tract

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 syndromeLung hypoplasia and ipsilateral anomalous systemic venous drainageAnomalous right pulmonary vein drains into IVC, hepatic or portal vein, coronary sinus or right atriumMost asymptomaticLeft-to-right shunt  can lead to pulmonary hypertension Imaging Similar to isolated lung hypoplasia – increased opacity of one hemithorax, mediastinal shift, contralateral lung hyperinflationAnomalous vein – tubular shadow, runs to base…

Congenital lobar hyperinflation

Bronchial abnormalityCheck-valve mechanism, causes progressive hyperinflation of affected lobeTends to reduce with time in asymptomatic patientsNeeds excision in symptomatic children Imaging Left upper lobe (42%)Right middle lobe (35%)Radioopacity in affected lobe in postnatal period due to fluidWith time, hyperinflation with hyperlucency of affected lobeCT: rules out other causes – vascular anomalies, compression of bronchi or…

Idiopathic pulmonary hemosiderosis

Rare, unknown etiologyChildren 0-10 yearsEpisodic intra-alveolar hemorrhageHemoptysisIron-deficiency anemiaAirspace opacities on plain filmRepetitive 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 granulomatosisPrimary (idiopathic) small vessel vasculitidesNecrotizing granulomatous inflammation of small vessels of upper and lower respiratory tractM=FAny age of presentationLungs affected in 90% of casesCough, dyspnea, pleuritic chest pain, hemoptysisc-ANCA directed against proteinase-3 is positive Imaging Chest XrayBilateral nodules or massesNodules from few mm to 10 cmNo zone predilectionNodules larger than 2 cm…

Chronic eosinophilic pneumonia

Protracted courseMore symptomaticMild to moderate eosinophiliaElevated serum IgE in peripheral bloodGood prognosisPatients respond to steroids Imaging Chest XrayPatchy non-segmental consolidationInvolves mid and upper zonesOpacities peripheral and parallel to chest wall – photographic negative of pulmonary edemaCTSame findings as plain film, more apparent in CTDifferential: organizing pneumonia. Nodules are more common in organizing pneumonia rather than…

Alveolar proteinosis

Accumulation of periodic acid Schiff positive lipoproteinaceous material in alveoliDue to abnormal surfactant clearance from lungsFault in GM-CSF signaling Primary – idiopathic due to anti GM-CSF antibodiesSecondary – dust inhalation, infections, myelodysplasia, lymphoma, myeloid leukemia20-50 years M>FMore in childrenDefinitive diagnosis: bronchoalveolar lavage, biopsy Imaging Chest XrayNonspecificBoth lungs affectedAirspace opacification predominantly in central lung – bat’s-wing appearanceCTCrazy paving…

Alveolar microlithiasis

Deposition of tiny stones mainly made of calcium phosphate in air spacesMutations in SLC34A2 gene. This gene codes for sodium dependent phosphate transporter in type II alveolar cellsCauses phosphate accumulation30-50 years ageAsymptomatic at presentation Imaging Chest XrayWidespread discrete high density opacities (resembling sand grains)When profusely involving lungs, similar to a white out appearanceObscuration of heart…

Simple pulmonary eosinophilia

Loffler’s syndromeElevated eosinophil count in peripheral bloodAssociation with parasitic infection – Ascaris lumbricoides Imaging Chest XrayFleeting transient infiltratesUni or bilateralResolution of opacities within days and maximum one monthCTGround-glass opacities, consolidationPeriphery of mid and upper lung zonesSingle or multiple acinar nodules Read more Jeong, Yeon Joo, et al. “Eosinophilic lung diseases: a clinical, radiologic, and pathologic…

Limitations of portable chest radiography

Scattered radiationInability to capture all relevant informationSignificant underexposure increases noise and reduces contrast resolutionShorter focus-detector distance causes undesirable magnificationHigh 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 positionpoor inspirationobesitypregnancyabdominal distension (ascites, intestinal obstruction, abdominal mass)diffuse pulmonary fibrosislymphangitis carcinomatosadisseminated lupus erythematosusbilateral basal pulmonary embolipainful conditions (after abdominal surgery)bilateral diaphragmatic paralysis

Unilateral elevation of diaphragm

posture – lateral decubitus position (dependent side)gaseous dissension of stomach or colondorsal scoliosispulmonary hypoplasiapulmonary collapsephrenic nerve palsyeventrationpneumonia or pleurisypulmonary thromboembolismrib fracturesubphrenic infectionsubphrenic mass

Lines and tubes in neonates

endotracheal tube tip varies with head and neck motiontip should be above carina consider chin position nasogastric tube within stomach nasojejunal tube include weighted tipside hole at duodenojejunal flexure umbilical arterial line tip between T6 and T9course inferiorly within umbilical artery into internal and common iliac arteries, then into aorta umbilical venous line tip at…

Neonatal pneumonia

occurs perinatallyascending infection from vaginatransvaginally during birthhospital acquired infection in post natal periodprolonged rupture of membranes is a known riskinfant swallows or aspirates infected amniotic fluid or vaginal tract secretionsGroup B streptococcus most common organism imaging severe acute symptoms first 24-48 hours coarse bilateral asymmetrical alveolar opacification with or without interstitial change pleural effusionpulmonary hyperinflationmild…

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 conditionseen post caesarean section, hypoproteinemia, hyponatremia, maternal fluid overload seen in small hypotonic sedated infants with precipitous deliverymild to moderate respiratory distress without cyanosis in first few hourscomplete…

Idiopathic respiratory distress syndrome

hyaline membrane diseaseaffects premature infant < 36 weeks deficiency of lipoprotein pulmonary surfactant and structural immaturity of lungs pathophysiology lipoproteins produced by type II pneumocytesconcentrated in cell lamellar bodiesthen transported to cell surface and expressed on alveolar luminal surfacelipoproteins combine with surface surfactant proteins A, B, C and D to form tubular myelintubular myelin lowers…

Normal lung development

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

Neonate chest

AP and transverse diameter equal, giving a cylindrical configurationrotation assessed by comparing length of anterior ribsnormal cardiothoracic ratio up to 0.6variable thymic sizethymic 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 seenminimal fluid best detected in lateral decubitus radiograph200 to 500 ml fluid needed for blunting of posterior and lateral costophrenic angleshomogenous opacification of lower chestobliteration of costophrenic angle and hemidiaphragmsuperior margin of opacity concave to lung and higher laterally than mediallyabove and medial to meniscus, hazy increase in opacity…

Pleural effusion

Types of effusion transudateexudate (thin or thick)blood chyle bile CSFiatrogenic fluids Bilateral pleural effusion tend to be transudatesdue to rise in capillary pressure or fall in blood proteinsexudative bilateral effusion: metastasis, lymphoma, pulmonary embolism, rheumatoid disease, SLE, post-cardiac injury syndrome, myxedema and some ascites related effusions Right sided effusions ascitesheart failureliver abscess Left sided effusions…

Azygos fissure

How to pick pleural effusion on a chest Xray