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Hrct iii
 

Hrct iii

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APPROACH TO AREAS OF INCREASED ATTENUATION IN HRCT

APPROACH TO AREAS OF INCREASED ATTENUATION IN HRCT

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    Hrct iii Hrct iii Presentation Transcript

    • PRESENTED BY : DR SHAMIMGUIDED BY : DR A PATIL (MD)
    • LINEAR AND RETICULAR OPACITIES NODULES AND NODULAR INCREASED LUNG OPACITIES ATTENUATION PARENCHYMAL Consolidation OPACIFICATION Ground glassHRCT PATTERN CYSTIC LESIONS, EMPHYSEMA, AND BRONCHIEACTASIS MOSAIC ATTENUATION AND PERFUSION DECREASED LUNG ATTENUATION AIR TRAPPING ON EXPIRATORY SCANS
    • Thickened SeptaPulmonaryveins SMOOOOTHHH...
    • Interlobular septalthickening associatedwith several septalnodules givingbeaded appearance
    • Irregular reticular opacities(arrows) in a patient withidiopathic pulmonary fibrosisshows
    • IS IT IN CONTACT WITH PLEURA NO YESCENTRILOBULAR PERILYMPHATIC RANDOM
    • Miliary TB
    • • Random – touch pleura – scattered in lung• Centrilobular –away from pleura• Perilymphatic – around vessels, bronchi – touch pleura or fissure
    • LINEAR AND RETICULAR OPACITIES NODULES AND NODULAR INCREASED LUNG OPACITIES ATTENUATION PARENCHYMAL Consolidation OPACIFICATION Ground glassHRCT PATTERN CYSTIC LESIONS, EMPHYSEMA, AND BRONCHIEACTASIS MOSAIC ATTENUATION AND PERFUSION DECREASED LUNG ATTENUATION AIR TRAPPING ON EXPIRATORY SCANS
    • ConsolidationGround-glass opacityHigh attenuationopacities & calcification 21
    • LINEAR AND RETICULAR OPACITIES NODULES AND NODULAR INCREASED LUNG OPACITIES ATTENUATION PARENCHYMAL Consolidation OPACIFICATION Ground glassHRCT PATTERN CYSTIC LESIONS, EMPHYSEMA, AND BRONCHIEACTASIS MOSAIC ATTENUATION AND PERFUSION DECREASED LUNG ATTENUATION AIR TRAPPING ON EXPIRATORY SCANS
    • LINEAR AND RETICULAR OPACITIES NODULES AND NODULAR INCREASED LUNG OPACITIES ATTENUATION PARENCHYMAL Consolidation OPACIFICATION Ground glassHRCT PATTERN CYSTIC LESIONS, EMPHYSEMA, AND BRONCHIEACTASIS MOSAIC ATTENUATION AND PERFUSION DECREASED LUNG ATTENUATION AIR TRAPPING ON EXPIRATORY SCANS
    •  what is consolidation? Increased attenuation, which results in obscuration of the underlying vasculature, usually producing air bronchogram. what is replacing the air in the alveoli? Pus, edema, blood or tumor cells . Even fibrosis as in UIP, NSIP can replace the air and cause consolidation 24
    •  Pneumonias (Bacterial, mycoplasma, PCP) Pulmonary edema due to heart failure or ARDS Hemorrhage Acute eosinophilic pneumonia When consolidation is evident on a CXR, HRCT does not usually provide additional diagnostically useful information
    • 47-year old female patient with a dry cough, slightly breathless.The first chest film shows bilateral consolidations in the lower lobes (arrow)After two weeks Rx with antibiotics, there is no improvement.The differential diagnosis now includes
    •  Organizing Pneumonia Chronic eosinophilic pneumonia Bronchoalveolar carcinoma or lymphoma Fibrosis in UIP and NSIP
    • Low-gradefever, progressive shortnessof breath .We see patchy non-segmental consolidations ina subpleural distribution.
    •  Organizing Pneumonia Chronic eosinophilic pneumonia Bronchoalveolar carcinoma or lymphoma Fibrosis in UIP and NSIP
    • Low-gradefever, progressive shortnessof breath .We see patchy non-segmental consolidations ina subpleural distribution.There was a markedeosinophilia in theperipheral blood.
    •  Idiopathic condition characterized by filling of alveoli by an infiltrate primarily eosinophils. Present with fever, cough, weight loss, malaise, and shortness of breath. Increased number of eosinophils in the peripheral blood Patients respond promptly to steroids.
    •  Peripheral consolidations with upper lobe predominance (‘photo negative’ of pulmonary edema).
    •  Organizing pneumonia Loeffler syndrome (eosinophilia and vanishing peripheral consolidations) Churg-Strauss syndrome (also serum eosinophilia, asthma, systemic vasculitis affecting multiple organs: renal insufficiency, arthralgia and myocarditis and pericarditis)
    • similarities between chronic eosinophilic pneumonia(left) and organizing pneumonia(right).Differentiation has to be made on the basis of clinical and laboratory findings
    •  Aka., Bronchiolitis Obliterans with Organizing Pneumonia (BOOP) An inflammatory process in which the healing process is characterized by organization and cicatrization of the exudate rather than by resolution and resorption unresolved pneumonia’.
    •  Several-months of nonproductive cough, low-grade fever, malaise and shortness of breath. A great mimicker Actually Is a diagnosis of exclusion. Good response to corticosteroid therapy and a good prognosis.
    •  Is mostly idiopathic and then called cryptogenic, Is also seen in patients with,
    • • Infection (bacterial, viral, PCP)• Drugs (antibiotics, amiodarone, cocaine)• Connective tissue disorders (SLE, RA, Sjogren syndrome, dermatomyositis).• Toxic-fume inhalation.• Organ Transplantation• Miscellaneous (inflammatory bowel dx, primary biliary cirrhosis, lymphoma, hematologic malignancies)
    • Typical :Bilateral, patchy ground glass attenuation orconsolidation with peripheral, lower zonedistribution frequently migratoryReversed halo sign
    • central ground-glassopacity andsurrounding air-spaceconsolidation ofcrescentic and ringshapes
    • central ground-glassopacity andsurrounding air-spaceconsolidation ofcrescentic and ringshapes)
    • Bilateral peripheral consolidations of OP.After exclusion of other diseases such asinfection, lymphoma, br onchoalveolar carcinoma, thediagnosis of cryptogenic organizing pneumonia was made.
    • A patient with rheumatoid arthritis and bilateral peripheral consolidations
    •  Chronic eosinophilic pneumonia Bronchoalveolar cell carcinoma Lymphoma Aspiration pneumonia Pulmonary infarction
    • Chronic eosinophilic pneumonia (left) versus Organizing pneumonia (right)
    • Ground glass Consolidation •Hazy attenuation •Denser attenuation •Vessels seen •Obscuration of vessels •dark bronchus sign •air bronchogram‘.
    •  Hazy increased attenuation of lung, Preservation of vascular margins Result of replacement of air in the alveoli by fluid, cells or fibrosis May also be due to volume averaging of morphological abnormality too small to be resolved NB :: Ground Glass opacity should be diagnosed only on scans obtained with thin sections : with thicker sections volume averaging is more - leading to spurious GGO,
    • Decreased air content without totally obliterating the alveoli # Normal expiration # Partial collapse of alveoliFilling of the alveolar spaces with pus, edema, hemorrhage, inflammation or tumor cells. # Partial filling of air spacesThickening of the interstitium or alveolar walls below the spatial resolution of the HRCT as seen in fibrosis. # interstitial thickening # Increased capillary blood volume
    • So, ground-glass opacification may either be the result of air space disease (filling of the alveoli) or interstitial lung disease (i.e. fibrosis).
    •  Nonspecific but important finding since,  60-80% of patients with ground-glass opacity have active potentially treatable disease  20-40% of cases, disease is not treatable and pattern is the result of fibrosis In the absence of fibrosis, mostly indicates the presence of an ongoing, active, potentially treatable process
    • PneumoniaEdema Hemorrhage
    • Organising pneumonias Hypersensitivity pneumoniaNon specific pneumonia (NSIP)Pulmonary alveolar proteinosis
    •  Immune reaction to inhaled antigens in dust Clue—exposure history HRCT-ground glass opacity
    •  Subacute:  Ill-defined Centrilobular Micronodules (reflecting the bronchiolocentric nature of inflammation),  Diffuse Bilateral Ground-glass Opacification (due to the lymphoplasmacytic inflammatory infiltrate)  Air- Trapping (because of small airways obstruction).  Mosaic Pattern : combination of patchy ground- glass opacity due to lung infiltration and patchy lucency due to bronchiolitis with air trapping
    •  Chronic :  Reticular Pattern with parenchymal distortion (indicating lung fibrosis) intermingled with areas of decreased attenuation; sometimes called the “head-cheese” sign.  Occasionally indistinguishable from UIP. Fibrosis of HP does not have a predilection for the periphery and lower zones and is often associated with ground-glass opacification, micronodules and air- trapping.
    • Subacute hypersensitivity pneumonitis with ill-defined centrilobular nodules
    • Mosaic Pattern.Some lobules demonstrate ground-glass opacity due to lung infiltration, whileothers are more lucent due to bronchiolitis with air trapping
    • Homogeneous, uniform pattern of cellular interstitial inflammationAssociated with variable degrees of fibrosis.
    •  Associated with, collagen vascular disease, drug reaction Good response to steroids, ( unlike UIP) As in UIP mainly involves the dependent regions of the lower lobes, but NSIP lacks the extensive fibrosis with honeycombing.  In contrast, UIP is associated with extensive fibrosis which is temporally inhomogeneous (i.e. various lesions are of different ages).
    •  specific entity or wastebasket diagnosis very inhomogeneous group  type I :cellular pattern seen as ground glass opacity  type IV :fibrotic pattern, indistinguishable from UIP.
    • Known case of dermatomyositis with breatlessness.
    •  The predominant finding is ground glass opacity (GGO). There is very subtle traction bronchiectasis, indicating that the GGO is the result of fibrosis and therefore irreversible. NSIP is by far the most common interstitial lung disease in patients with connective tissue disease.
    • Areas of ground-glass and traction bronchiectasesMore extensive abnormalities in the lower lungBut honeycombing is typically lacking.Mildly dilated esophagus,
    •  Not a diagnosis on its own , is a pattern of lung damage. The diagnosis of NSIP requires histological proof. For the pathologist the key feature is the uniformity of the abnormality within the lung. The role of the radiologist is more to ‘exclude UIP pattern’ rather than to make the diagnosis of NSIP. In all patients with a NSIP , the clinician should be advised to look for connective tissue diseases, hypersensitivity pneumonitis or drugs
    •  Heterogenous group of disorders represent fundamental responses of the lung to injury and do not represent diseases per se. These diseases have specific patterns of morphologic findings on HRCT and histology. These patterns are also common findings in collagen vascular diseases (e.g., sclerodermia, rheumatoid arthritis) and drug-related lung diseases. For instance in patients with rheumatoid arthritis findings of NSIP, UIP, OP and LIP have been reported. IIPs include seven entities in order of relative frequency.
    • The differentiation between NSIP and UIP has tremendous prognostic implication for the patient. UIP is more progressive and more than 50% of patients with UIP die within 3 years.
    •  Honeycombing consisting of multilayered thick- walled cysts. Architectural distortion with traction bronchiectasis due to fibrosis. Predominance in basal and subpleural region. Mild mediastinal lymphadenopathy
    • layered peripheral cysts, stacked one on top of the other
    •  Is a pathology diagnosis at lungbiopsy, when honeycombing is visible. If the UIP pattern is of unknown cause (i.e. idiopathic), the disease is called Idiopathic pulmonary fibrosis (IPF). IPF accounts for more than 60% of the cases of UIP. Diagnosis of IPF requires exclusion of other known causes of UIP including drug toxicities, environmental exposures (asbest), and collagen vascular diseases like RA, SLE, polyarteritis nodosa and sclerodermia.
    • Photomicrograph of histopathologic specimen(low-power view) shows typical patchyinterstitial fibrosis and areas of microscopichoneycombing (arrows)
    • 57-year-old man with biopsy-provenidiopathic pulmonary fibrosis. Grosspathologic specimen from autopsyshows predominantly lowerlobe, peripheral, and subpleuralfibrotic lesions that alternate withareas of normal lung (asterisks).Honeycombing cysts are seen insubpleural regions (arrow).
    • Honeycombing Bronchiectasis
    • Honeycombing Emphysema
    • Honeycombing Cystic lung disease
    • Reticular pattern – no honeycombing Reticular pattern - honeycombing
    • • Reticular abnormality• Honeycombing with or without traction bronchiectasis• Subpleural basal predominance• Absence of features inconsistent with these
    • Lower zone – UIP pattern Upper zone - chronic hypersensitivity pneumonitis
    • Long standing sarcoidosis with fibrosis – upper and mid-zone fibrosis
    • emphysema in the upper lobes and a UIP pattern in the lower lobes
    • UIP NSIP• Honeycombing • Ground glass• Subpleural • Septal lines• Lower lungs • Lower lungs• Clinical- • Clinical-better fibrosis, poor prognosis prognosis
    •  ‘Crazy Paving is a combination of ground glass opacity with superimposed septal thickening in a patchy distribution. Some lobules are affected and others are not. It was first thought to be specific for alveolar proteinosis,.
    • Combination of ground glass opacity andseptal thickening : Alveolar proteinosis.
    •  Abnormal surfactant metabolism Filling of the alveolar spaces with PAS positive material 30 - 50 years old. Nonproductive cough, fever, and mild dyspnea The diagnosis is based on the suggestive HRCT pattern (crazy paving) and the characteristic features of BAL fluid (Broncho Alveolar Lavage)
    • Accumulation of PAS positive material withinthe alveoli and thickening of the interstitium.
    •  Patchy but geographical ground-glass opacification, With a network of smoothly thickened interlobular septa (termed the “crazy paving” pattern). the proteinacious material, which is removed from the alveolar space by macrophages is transported to the interstitium and thus leads to thickening of septa the appearances are not pathognomonic of the disease
    • “Crazy-paving” in a patient with alveolar proteinosis.There is ground-glass opacification in a patchy butgeographical distribution on which a network of smoothly-thickened interlobular septa is superimposed.
    •  Alveolar proteinosis Infection (PCP, viral, Mycoplasma, bacterial) NSIP Organizing pneumonia (COP/BOOP) Neoplasm (Bronchoalveolar Ca) Pulmonary hemorrhage Edema (heart failure, ARDS, AIP) Sarcoid
    •  Pneumocystis jiroveci Opportumistic infection in immunocompromised Nowadays PCP is seen more in immunosuppressed patients, i.e. transplant recipients and patients on chemotherapy.
    •  Perihilar or diffuse ground-glass opacification. Thickened septal lines with areas of ground-glass ( Crazy Paving ) Later, cysts (or pneumatoceles) in 10-35% , typically involving upper lobes ; bizarre shapes, thick walls Pneumothorax in 35% of patients with cysts Following therapy : complete disappearance, or residual nodules or scars
    • Immunocompromised patient with PCP. The CT findings are diffuse ground-glass opacification.The findings are not specific for PCP, but in this clinical setting PCP is the most likely diagnosis.
    • LINEAR AND RETICULAR OPACITIES NODULES AND NODULAR INCREASED LUNG OPACITIES ATTENUATION PARENCHYMAL Consolidation OPACIFICATION Ground glassHRCT PATTERN CYSTIC LESIONS, EMPHYSEMA, AND BRONCHIEACTASIS MOSAIC ATTENUATION AND PERFUSION DECREASED LUNG ATTENUATION AIR TRAPPING ON EXPIRATORY SCANS
    • DECREASED LUNG ATTENUATION
    • LINEAR AND RETICULAR OPACITIES NODULES AND NODULAR INCREASED LUNG OPACITIES ATTENUATION PARENCHYMAL Consolidation OPACIFICATION Ground glassHRCT PATTERN CYSTIC LESIONS, EMPHYSEMA, AND BRONCHIEACTASIS MOSAIC ATTENUATION AND PERFUSION DECREASED LUNG ATTENUATION AIR TRAPPING ON EXPIRATORY SCANS
    • MOSAIC ATTENUATION AND PERFUSION• Definition: Heterogeneous lung density having a zonal or geographic pattern of distribution with areas of “groundglass attenuation” alternating with areas of “decreased” lung density
    •  Lung density and attenuation depends partially on amount of blood in lung tissue. Mosaic perfusion refers to areas of decreased attenuation which results from regional differences in lung perfusion secondary to airway disease or pulmonary vascular disease.
    • May be due to , vascular obstruction,abnormal ventilation or airway disease 131
    •  The pulmonary arteries will be reduced in size in the lucent lung fields thus allowing mosaic perfusion to be distinguished from ground-glass opacities.
    •  Patchy ground glass infiltrates resulting from airspace/interstitial disease: eg PCP Air-trapping resulting from airway obstruction: eg constrictive bronchiolitis Vascular disease: eg. chronic embolic PHT
    •  Parenchymal disease: high attenuation regions are abnormal and represent ground-glass opacity Obstructive small airways disease: low attenuation regions are abnormal and reflect decreased perfusion of the poorly ventilated regions, e.g. bronchiectasis, cystic fibrosis, constrictive bronchiolitis Occlusive vascular disease: low attenuation regions are abnormal and reflect relative oligaemia e.g. Chronic pulmonary embolism
    •  Peripheral Vessels : if vessels in hypoattenuated regions of the lung are smaller than in the other regions, the pattern is due to mosaic perfusion (i.e. airways or vascular disease rather than ground- glass) Central Vessels : pulmonary hypertension, reflected as dilatation of the central pulmonary arteries, suggests a vascular cause Small Airways : the presence of abnormally dilated or thick walled airways in the relatively lucent lung confirms underlying airway disease
    •  Parenchymal Changes : ground glass opacity is the likely cause if other features of infiltrative disease are present, Air Trapping : refers to regions of lung which following expiration do not show the normal increase in attenuation. The presence of air trapping suggests airway disease
    • # Areas of increased attenuation have relatively large vessels, while areas of decreased attenuation have small vessels.# Air trapping and bronchial dilatation commonly seen.# Causes include: Bronchiectasis, cystic fibrosis and bronchiolitis obliterans. 138
    • # Decreased vessel size in less opaque regions is oftenvisible# Dilatation of the central pulmonary arteries# common in patients with acute or chronic pulmonary embolism (CPE),
    • MOSIAC PATTERN DEPENDENT LUNG ONLY NONDEPENDENT LUNG EXPIRATION PRONE POSITION NO AIR TRAPPING NOT AIR TRAPPING RESOLVE RESOLVE VESSEL SIZE PLATE GROUNDATELECTASIS GLASS AIRWAYS DECREASED NORMAL DISEASE GROUND VASCULAR GLASS 140
    • The vessels within the areas of abnormally low attenuation aresmaller than their counterparts in areas of normal lungattenuation. 142
    •  Air-space Disease  Pcp, Edema Interstitial Disease  Fibrosis/Microscopic  Honeycombing Combined Air-space / Interstitial Disease
    •  Large airway disease  Bronchiectasis Small airway disease  Constrictive bronchiolitis Asthma
    • Air trapping on expiratory imaging in the absence of inspiratoryscan findings in a patient with bronchiolitis obliterans.
    •  Chronic pulmonary embolism Pulmonary hypertension 2° increased pulmonary pressure
    • Mosaic perfusion pattern with marked regional variations in attenuation of the lungparenchyma and disparity in the size of the segmental vessels, with larger-diametervessels in regions of increased attenuation (arrows). A peripheral parenchymal bandor scar (arrowhead) from infarction also is depicted.
    • mosaic lung attenuation, with segmental and subsegmentalperfusion defects. A small pleura-based opacity (arrowhead)caused by previous infarction is seen in the apical segment of theright lower lobe.
    • Mosaic Algorithm Air trapping Small SmallAirways Vessel
    • Inspiratory
    • Expiratory
    •  It refers to mixed densities # Consolidation # Ground Glass Opacities # Normal Lung # Mosaic Perfusion• Signifies mixed infiltrative and obstructive disease
    • HRCT scan shows lungwith a geographicappearance, whichrepresents acombination of patchyor lobular ground-glass opacity (smallarrows) and mosaicperfusion (largearrows).
    • Common cause are : 1. Hypersensitive pneumonitis 2. Sarcoidosis 3. DIP 166
    • A patient with hypersensitivity pneumonitis shows acombination of ground-glass opacity, normal lung, andmosaic perfusion (arrow) on the same inspiratory image. 167
    • Bilateral multiple centrilobular nodules
    • Ground-glass opacification in a geographical distributionwith smoothly-thickened interlobular septa
    • Bilateral peripheral consolidations with reverse halo
    • Tree in Bud
    • Air trapping on expiratory imaging
    • Basal Honeycombing