The road to HRCT evaluation of pediatric diffuse lung diseases .part 1
The road to HRCT evaluation of Dr/Ahmed Bahnassy Consultant Radiologist Riyadh Military Hospital
Does chILD differ from adILD?1. Differences in the immune system responces, cytokine and growth factors2. Histologic classification differs significantly3. Specific types presented at children not adults4. Rarer and less stereotyped than adult ILD5. More difficult to treat than adults.
Examples of common terms of chILD DIP Desquamative interstitial pneumonitis CIP Chronic pneumonitis of infancy NSIP Non-specific interstitial pneumonitis FB/LIP Follicular bronchiolitis /lymphoid Interstitial Pneumonia OP Organizing pneumonia (old BOOP) PIG Pulmonary interstitial glycogenosis NEHI Neuroendocrine cell hyperplasia of infancy* UIP: Usual interstitial pneuminitis is rare in children.
• Second round • Third round investigations: investigations: 1. Lung biopsy1. Upper GI study for ? H type (Transbronchial,percutaneous, fistula thoracoscopic, open lung) CT2. Bronchoscopy and BAL for guided from affected patch and cytology (LCH, iron laden unaffected patch. macrophages, PAP) and • Special stains (eg. Bompesin or cultures PAS) • Immunoblotting for sufactant3. Videofluroscopy for aspiration proteins at lung biopsy evidence • Electron microscopy study of4. Cardiac Cath biopsy5. Detailed lymphocyte function • DNA for mutations in SPB, SPC tests and ABCA36. TB –Elispot test
Glossary ofTerms of HRCT Same terminology for both adults and pediatrics
beaded septum signThis sign consists of irregularand nodular thickening of interlobularsepta reminiscent of a row of beads
bronchiectasisBronchiectasis is irreversiblelocalized or diffuse bronchial dilatation,usually resulting from chronic infection,proximal airway obstruction, orcongenital bronchial abnormality
signet ring signThis finding is composed ofa ring-shaped opacity representing a dilatedbronchus in cross section and asmaller adjacent opacity representingits pulmonary artery, with the combinationresembling a signet (or pearl) ring.
bronchiolectasis Bronchiolectasis is defined as dilatation of bronchioles. It is caused by inflammatory airways disease (potentially reversible) or, more frequently, fibrosis
bronchoceleA bronchocele is bronchialdilatation due to retained secretions(mucoid impaction) usually caused byproximal obstruction, either congenital(eg, bronchial atresia) or acquired (eg,obstructing cancer)
bronchocentricThis descriptor is applied todisease that is conspicuously centeredon macroscopic bronchovascular bundlesExamples of diseases witha bronchocentric distribution includesarcoidosis , Kaposi sarcoma ,and organizing pneumonia .
broncholithA broncholith, a calcifiedperibronchial lymph node that erodesinto an adjacent bronchus, is most oftenthe consequence of Histoplasma or tuberculousinfection.
cavityA cavity is a gas-filled space, seen as alucency or low-attenuation area, withinpulmonary consolidation, a mass, or anodule
crazy-paving patternThis pattern appears asthickened interlobular septa and intralobularlines superimposed on abackground of ground-glass opacity , resembling irregularly shaped pavingstones.
cystA cyst is any round circumscribedspace that is surrounded by anepithelial or fibrous wall of variablethickness
consolidationConsolidation refers to anexudate or other product of disease thatreplaces alveolar air, rendering the lungsolid (as in infective pneumonia).
ground-glass opacityArea of hazy increased lungopacity, usually extensive, within whichmargins of pulmonary vessels may beindistinct. On CT scans, it appears ashazy increased opacity of lung, withpreservation of bronchial and vascularmargins
halo signThe halo sign is a CT findingof ground-glass opacity surrounding anodule or mass..It refers to severe pulmonary infection..firstdescribed with invasive aspergillosis in leukemic patients .
reversed halo signThe reversed halo sign is afocal rounded area of ground-glassopacity surrounded by a more or lesscomplete ring of consolidation .A rare sign, it was initially reported tobe specific for cryptogenic organizingpneumonia but was subsequentlydescribed in patients with paracoccidioidomycosis
honeycombingHoneycombing representsdestroyed and fibrotic lung tissue containingnumerous cystic airspaces withthick fibrous walls, representing the latestage of various lung diseases, withcomplete loss of acinar architecture.The cysts range in size from a few millimetersto several centimeters in diameter, andhave variable wall thickness.
parenchymal bandIt is a linear opacity, usually1–3 mm thick and up to 5 cm long thatusually extends to the visceral pleura(which is often thickened and may beretracted at the site of contact).It reflects pleuroparenchymal fibrosisand is usually associated with distortionof the lung architecture.
mycetomaA mycetoma is a discretemass of intertwined hyphae, usually ofan Aspergillus species, matted togetherby mucus, fibrin, and cellular debris colonizinga cavity, usually from prior fibrocavitarydisease (eg, tuberculosis orsarcoidosis)
tree-in-bud patternThe tree-in-bud pattern representscentrilobular branching structuresthat resemble a budding tree. Thepattern reflects a spectrum of endo- andperibronchiolar disorders, including mucoidimpaction, inflammation, and/or fibrosis
Secondary Pulmonary Lobule disease patterns Same usage for both adults and pediatrics with different significance
The “Unit” of the lungThe secondary pulmonary lobule is a fundamental unit oflung structure, and it reproduces the lung in miniature.Airways, pulmonary arteries, veins, lymphatics, and thelung interstitium are all represented at the level of thesecondary lobule.
Tree-in-budin patients with a centrilobulardistribution of nodules, if the tree-inbudsign can be recognized the differentialdiagnosis is limited:Endobronchial spread of tuberculosisor nontuberculous mycobacteriaBronchopneumonia,infectious bronchiolitisCystic fibrosis ,bronchiectasis of anycausediffuse panbronchiolitisasthma or allergic bronchopulmonaryaspergillosis , constrictivebronchiolitis , follicular bronchiolitis,bronchioloalveolar carcinoma, and intravascular metastases.
Centrilobular emphysemaCentrilobular (centriacinar) emphysemais characterized histologicallyby areas of lung destruction occurringin relation to centriacinarbronchioles and, therefore, is locatedin the center of the secondary lobuleor surrounding the centrilobular region
Lobular Process Pneumonia Hypersensitivity pneumonitis
Headcheese sign in hypersensitivity pneumonitis The headcheese sign is indicative of mixed infiltrative and obstructive disease, usually associated with bronchiolitisThe most common causes of this patternare hypersensitivity pneumonitis, desquamativeinterstitial pneumonia or respiratorybronchiolitis–interstitial lung disease,sarcoidosis, and atypical infectionswith associated bronchiolitis, such as occurswith M pneumoniae.
Consider the distribution of the pathology Same principle for both adults and pediatrics.for DD