- Ground-Glass Opacity: significance
- morphologic abnormalities below the resolution of HRCT
- histology nonspecific
- air space disease in 14%
- interstitial disease in 54%
- mixed disease in 32%
- acute or chronic symptoms?
Leung et al. Radiology 1993; 188:219-214 - Ground-Glass Opacity:
acute symptoms
1. distribution of GGO doesn’t help much
2. differential diagnosis
- » pulmonary edema
- » hemorrhage
- » atypical pneumonia (e.g. PCP, viral)
- » diffuse alveolar damage (DAD, ARDS)
3. evaluation based on clinical suspicion - Ground-Glass Opacity with chronic symptoms
- hypersensitivity pneumonitis
- interstitial pneumonias (e.g. NSIP, DIP)
- organizing pneumonia (OP, BOOP)
- eosinophilic pneumonia
- bronchioloalveolar carcinoma (BAC); now invasive mucinous adenocarcinoma
- lipoid pneumonia (rare)
- alveolar proteinosis (rare)
- Per R. Webb Orlando 2012 - Hypersensitivity Pneumonitis (HP)
- a common disease
- caused by inhalation of organic antigens
- acute, subacute, and chronic stages
- usually presents in the subacute stage
- repeated exposures produce fever, chills, dry cough, dyspnea
- progressive symptoms over months or years
- Per R. Webb Orlando 2012 - Subacute Hypersensitivity Pneumonitis: histology predicts the HRCT findings
- alveolitis: diffuse or patchy GGO (50-75%)
- peribronchiolar granulomas: ill-defined centrilobular nodules (50%), usually GGO
- cellular bronchiolitis: mosaic perfusion with air trapping on expiratory scans
- GGO + mosaic perfusion and/or air trapping
- diffuse or predominant in mid lung zones
- involves the entire cross section of lung
- Per R. Webb Orlando 2012 - Ground-Glass Opacity with chronic symptoms: distribution of disease
1. diffuse or patchy (geographic) opacities:
- » hypersensitivity pneumonitis most likely
2. concentric subpleural and lower lobe opacities:
- » interstitial pneumonia most likely
- (e.g. nonspecific interstitial pneumonia, NSIP)
- >> subpleural sparing, lower lobe predominance strongly suggest NSIP - (Idiopathic) Interstitial Pneumonias
- reactions to lung injury, not diseases
- several different patterns
- variable inflammation and fibrosis
- variable response to treatment
- sometimes idiopathic
- may be associated with collagen-vascular diseases, drugs, inhalation,
- other causes most common: NSIP, organizing pneumnia (OP), usual interstitial pneumonia (UIP)
- Per R. Webb Orlando 2012 - Nonspecific Interstitial Pneumonia (NSIP) Travis et al. Am J Respir Crit Care Med 2008; 177:1338
- less common than usual interstitial pneumonia (UIP)
- despite its name, it is a specific entity
- cellular (inflammatory) and fibrotic forms
- associated with collagen disease, drugs, idiopathic
- good response to Rx; 5-year survival 80-90%
- Per R. Webb Orlando 2012 - NSIP: HRCT findings
Johkoh et al. Radiology 2002; 225:199
Travis et al. Am J Respir Crit Care Med 2008; 177:1338
- concentric, basal, and subpleural distribution
- ground-glass opacity in 80-90%; usually indicates cellular NSIP
- reticular opacities in 50%, often fine in appearance
- traction bronchiectasis suggests fibrotic NSIP
- honeycombing uncommon (1-5%) and minimal in extent = fibrotic NSIP
- sparing of immediate subpleural lung in 50% - NSIP: Utility of HRCT
- suggest NSIP if a basal and subpleural distribution of ground-glass opacity or fine reticulation is unassociated with honeycombing
- biopsy is not usually performed if the patient has a history of collagen vascular disease (CVD)
- in a patient with CVD, NSIP is most common ILD
- biopsy often performed if the patient has no known underlying disease
- Per R. Webb Orlando 2012 - Organizing Pneumonia (OP)
- OP is a histologic pattern associated with the syndrome known as OP or BOOP
- the term cryptogenic OP (COP) is used for idiopathic OP
- common
- idiopathic, infection, drugs, C-V diseases, fumes
- several months of cough, dyspnea, low-grade fever
- responds to steroids, good prognosis
- Per R. Webb Orlando 2012 - Organizing Pneumonia: HRCT findings
- air space consolidation - 90%
- ground-glass opacity - 60%
- large nodules - 15%
- focal consolidation - 5%
- opacities often irregular in shape
- patchy peribronchial and subpleural opacities are typical - Perilymphatic Nodules: differential diagnosis
- sarcoidosis (common)
- lymphangitic spread of tumor (uncommon)
- silicosis and CWP (uncommon)
- amyloidosis (rare)
- lymphoid interstitial pneumonia (LIP; rare) - Centrilobular Nodules: differential diagnosis
- bronchopneumonia or endobronchial spread of infection (bacteria, TB, MAC, fungi, virus, PCP)
- hypersensitivity pneumonitis
- respiratory bronchiolitis (RB-ILD) in smokers
- other bronchiolitis (e.g. follicular bronchiolitis)
- endobronchial spread of tumor (mucinous adeno)
- edema, hemorrhage, vasculopathy (uncommon)
- HRCT: GGO or solid? diffuse or patchy? acute or chronic?
- Per R. Webb Orlando 2012 - Centrilobular Nodules: GGO
- chronic symptoms with diffuse GGO nodules strongly suggests HP: with a history of exposure, this is often considered diagnostic
- caveat: in a smoker, think of respiratory bronchiolitis (RB-ILD)
- with chronic symptoms and patchy GGO nodules think of mucinous adenocarcinoma (BAC)
- with acute symptoms: consider atypical infection (PCP, CMV), hemorrhage, or edema - Centrilobular Nodules: solid
- with solid (i.e. soft-tissue) CL nodules, the most likely diagnosis is infection (e.g. TB or bacteria); often patchy or focal
- mucinous adenocarcinoma
- history may help in diagnosis - Honeycombing: differential diagnosis
- it usually reflects the histologic pattern termed usual interstitial pneumonia (UIP); common, UIP results in 25-50% of IP cases
- if no know associated disease or exposure: likely idiopathic pulmonary fibrosis (IPF) (60-70% cases)
- rheumatoid arthritis, scleroderma, other CVD
- drug-related fibrosis
- chronic hypersensitivity pneumonitis
- asbestosis (uncommon) - UIP: HRCT findings
- subpleural, posterior, lower lobe predominance
- irregular reticulation, often patchy
- traction bronchiectasis
- honeycombing in many (70%)
- ground-glass opacity rare as an isolated finding - Idiopathic Pulmonary Fibrosis (IPF)
- most common cause of UIP
- IPF --> UIP
- patients > 50 years of age
- progressive dyspnea
- mean survival 3 years
- no recognized treatment
- gradual progression in most
- Scleroderma of the Chest : Facts
- Bibasilar pulmonary fibrosis
- Productive cough common
- Hematemesis
-Pericarditis
- Dilated esophagus
- Aspiration pneumonia not uncommon - Scleroderma: CREST
- Calcinosis of the skin
- Raynaud Phenomenon
- Esophageal dysmotility
- Sclerodactyly
- Telangiectasia - Scleroderma: HRCT Findings
- Areas of ground glass attenuation
- Poorly defined subpleural nodules
- Reticular pattern of attenuation
- Traction bronchiectasis
- Honeycombing "Pulmonary artery diameter is not a reliable indicator of pulmonary hypertension in patients with pulmonary fibrosis.." The Effect of Diffuse Pulmonary Fibrosis on the Reliability of CT Signs of Hypertension
Devaraj A et al.
Radiology 2008;249;1042-1049 " Pulmonary artery dilatation occurs in the absence of pulmonary hypertension in patients with pulmonary fibrosis and is therefore an unreliable sign of pulmonary hypertension in these patients." The Effect of Diffuse Pulmonary Fibrosis on the Reliability of CT Signs of Hypertension
Devaraj A et al.
Radiology 2008;249;1042-1049 - Ernheim Chester Disease
- Triad of diffuse septal interstitial lung disease, pleural thickening , perirenal encasement and sclerotic bone lesions.
- Also known as Non-Langerhans cell histiocytosis of unknown etiology - Erdheim Chester Disease: Pleural Changes
- Smooth thickening of the pleural surfaces is usually bilateral and often symmetric - Erdheim Chester Disease: Parenchymal Changes
- Septal thickening often in association with visceral pleural thickening
- Septal thickening is often smooth and uniform
- Prominent centrilobular nodules
- Usually uniform throughout the lungs - Differential Diagnosis: Septal Lines
- Congestive heart failure
- Langerhans Cell Granulomatosis
- LCG and Erdheim Chester may co-exist
- Retroperitoneal fibrosis
- Congestive heart failure - Differential Diagnosis: Septal Lines
- Congestive heart failure
- Pulmonary edema
- Sarcoidosis
- Lymphangitic tumor
- Pulmonary veno-occlusive disease
- Diffuse pulmonary lymphangiomatosis - Erdheim Chester Disease: Renal Changes
- Perirenal fat effaced or infiltrated by soft tissue
- Usually bilateral and symmetric
- Infiltration of para-aortic regions is also common - Erdheim Chester Disease: Vascular Changes
- Periaortic infiltration which is usually circumferential and nonocclusive
- May involve aorta from root thru iliac vessels - Erdheim Chester Disease: Skeletal Changes
- Bilateral symmetric osteosclerosis of metaphyses and diaphyses especially in long bone. - Sarcoidosis: Key Facts
- Multiorgan granulomatous disease with multi-organ involvement
- Classic pathology is a noncaseating granuloma
- Usually affects young to middle age adults
- Highest prevalence in blacks
- More common in women than men - Sarcoidosis: Clinical Outcome
- Spontaneously remits in 1/3 of patients
- Chronic and progressive in 30% of patients
- Will prove fatal in 1-5% of patients (pulmonary or cardiac complcations) - Sarcoidosis: Key Facts
- Multiorgan granulomatous disease with multi-organ involvement
- Classic pathology is a noncaseating granuloma
- Usually affects young to middle age adults
- Highest prevalence in blacks
- More common in women than men - Sarcoidosis: Clinical Outcome
- Spontaneously remits in 1/3 of patients
- Chronic and progressive in 30% of patients
- Will prove fatal in 1-5% of patients (pulmonary or cardiac complcations) - "The spectrum of HRCT manifestations varies from typical findings that allow confident diagnosis to atypical patterns mimicking other disease, including predominance of ground glass opacity, consolidation, nodules, and typical distribution of lesions."
Idiopathic Pulmonary Fibrosis:Spectrum of High Resolution CT Findings
Souza CA et al.
AJR 2005; 185:1531-1539 - Idiopathic Pulmonary Fibrosis: Facts
- Symmetric bilateral reticulation
- Honeycombing involving subpleural regions especially in the lower lobes
- Architectural distortion of the lung parenchyma
- Increased incidence of lung cancer
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