Chung-2.00 - CPD University of Toronto · • Collard HR, Ryerson CJ, Corte TJ et al. Acute Exacerbation of Idiopathic Pulmonary Fibrosis. An International Working Group Report. Am

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Taebong Chung MD, FRCPCChest Radiologist

University Health Network, Mount Sinai Hospital, Women’s College Hospital

Assistant Professor, University of Toronto, Department of Medical Imaging

DIAGNOSIS OF USUAL INTERSTITIAL PNEUMONIA: KEY FACTS FOR THE

RADIOLOGIST

DISCLOSURES

• I have no actual or potential conflict of interest in relation to this program

OVERVIEW:• CLINCAL

• What is IPF (Idiopathic Pulmonary Fibrosis) and UIP (Usual Interstitial Pneumonia)

• Why is it important to differentiate IPF from other interstitial pneumonia

• RADIOLOGY

• Terminology

• CT Technique

• CT criteria for diagnosis of UIP

• IPF Special Topics

• CPFE (Combined Pulmonary Fibrosis and Emphysema)

• Acute Exacerbation of IPF

• Malignancy

IDIOPATHIC INTERSTITIAL LUNG DISEASE

• Fibrosing interstitial pneumonia

• UIP (Usual Interstitial Pneumonia) : Pathologic appearance of IPF

• Need to exclude other known causes of UIP

• NSIP (Non Specific Interstitial Pneumonia)

• Smoking Related Interstitial Lung Disease

• RB-ILD (Respiratory Bronchiolitis Interstitial Lung Disease)

• DIP (Desquamative Interstitial Pneumonia)

• Rare Lung Disease

• LIP (Lymphocytic Interstitial Pneumonia)

• IPPFE (Idiopathic pleuroparenchymal fibroelastosis)

• Hypersensitivity Pneumonitis

• Not an idiopathic interstitial pneumonia but can mimic these

DEFINITION: IDIOPATHIC PULMONARY FIBROSIS

• Specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause, occurring primarily in older adults, limited to the lungs, and associated with the histopathologic and/or radiologic pattern of UIP (Usual Interstitial pneumonia)

• i.e. IPF has UIP

• Requires exclusion of other forms of interstitial pneumonia including other idiopathic interstitial pneumonia and ILD associated with environmental exposure, medication, or systemic disease.

• i.e. NOT ALL UIP = IPF

*An Official ATS/ERS/JRS/ALAT Statement: Idiopathic Pulmonary Fibrosis: Evidence based Guidelines for Diagnosis and Manangement. Am J Resp and Crit Care Med, 2011

IDIOPATHIC PULMONARY FIBROSIS: KEY FACTS

• Incidence increases with older age

• Between 6-16 per 100,000

• Rare less than 50

• Younger consider connective tissue disease

• Smoking is strongly associated with IPF

• Poor prognosis but variable rate of progression

• Early studies 2-3 years median survival

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WHY IS IT IMPORTANT TO DIAGNOSE IPF/UIP?

N Engl J Med 2012;366-1968-77

PANTHER-IPF TRIAL• Compared:

• Prednisone, Azathioprine and N-acetylcysteine which was widely used treatment of IPF versus

• N-acetylcysteine by itself or

• placebo

• 50% of patients accrued when study ended early

• deaths 8 versus 1( P=0.01) and

• hospitalization of 23 versus 7 P<0.0001

• PLACEBO was better than treatment

• Continued with N-acetylcysteine versus placebo showed no benefit

• TAKE HOME MESSAGE: YOU DON’T WANT TO GIVE STEROIDS TO IPF

N Engl J Med 2012;366-1968-77

WHY IS IT IMPORTANT TO DIAGNOSE IPF/UIP: NEW IPF MEDICATIONS

• ATS/ERS/JRS/ALAT Clinical Practice Guideline: Treatment of Idiopathic Pulmonary Fibrosis: 2015

• Pirfenidone (Esbriet): Conditional Recommendation for use

• Nintedanib: Conditional Recommendation for use

• Antacids: Conditional Recommendation for use (for aspiration)

• Transplant

• Treatment for connective tissue fibrosis and NSIP are different than IPF

• Connective tissue fibrosis: Steroids, Cyclophosphamide, Mycophenolate

• NSIP: Steroids especially cellular NSIP, immunosuppressive drugs

• NEED ACCURATE DIAGNOSIS OF IPF FOR TREATMENT

RADIOLOGY IMAGING

• CT TERMINOLOGY

• CT TECHNIQUE

• CT CRITERIA FOR UIP

CT TERMINOLOGY

Fleischner Society: Glossary of Terms for Thoracic Imaging*

• Ground glass and consolidation

• Interlobular, Intralobular, Reticular

• Honeycombing and Traction Bronchiectasis

*Hansell et al. Fleischner Society: Glossary of Terms for Thoracic Imaging. Radiology 2008

TERMINOLOGY: GROUND GLASS AND CONSOLIDATION

• GROUND GLASS: “On CT scans, it appears as hazy increased opacity of lung with preservation of bronchial and vascular margins”

• CONSOLIDATION: “..appears as a homogeneous increase in pulmonary parenchymal attenuation that obscures the margins of vessels and airway wall.”

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TERMINOLOGY: INTERLOBULAR, INTRALOBULAR, RETICULAR

• INTERLOBULAR SEPTAL THICKENING:

“disease affecting one of the components of the septa…..render septa visible”

Interlobular septa: 10-20mm long that form the borders of lobules

• INTRALOBULAR LINES:

“fine linear opacities in a lobule when the intralobular interstitial tissue is abnormally thickened. …may appear as fine reticular pattern”

• RETICULAR

“collection of innumerable small linear opacities that, by summation produce an appearance resembling a net.”

TERMINOLOGY: RETICULAR, HONEYCOMBING

• HONEYCOMBING:

“the appearance is of clustered cystic air spaces, typically of comparable diameters on the order of 3-10mm but occasionally as large as 2.5cm. ….usually subpleural and is characterized by well-defined walls.”

“….the term should be used with care, as it may directly impact patient care.”

TRACTION BRONCHIECTASIS

“irregular bronchial and bronchiolar dilatation caused by surround retractile pulmonay fibrosis”

“juxtaposition of numerous cystic airways may make distinction from “pure” fibrotic honeycombing difficult”

CT TECHNIQUE

• Traditionally high resolution CT was 1mm every 10mm

• Currently: Volumetric/helical/spiral CT and reconstruct at any given thickness and interval.

• INITIAL WORK UP OF SUSPECTED INTERSTITIAL LUNG DISEASE

• Standard helical 3mm thickness inspiration

• High resolution 1mm every 10mm from helical scan

• PRONE helical images of bases if necessary (monitored if possible)

• To differentiate dependent changes from minor fibrosis

• Expiratory ultra low dose (10-20ma, standard low dose is 50ma)

• Looking for air trapping

• FOLLOW UP OF KNOWN INTERSTITIAL LUNG DISEASE

• Low dose 3mm inspiration in supine position only

TECHNIQUE: ROLE OF PRONE IMAGES

TECHNIQUE: EXPIRATORY

INSPIRATIONEXPIRATION

CT CRITERIA FOR UIP PATTERN*TABLE 4. HIGH-RESOLUTION COMPUTED TOMOGRAPHY

CRITERIA FOR UIP PATTERN

UIP Pattern (All Four Features) Possible UIP Pattern (All Three Features)

Inconsistent with UIP Pattern (Any of the SevenFeatures)

- Subpleural, basal predominance- Reticular abnormality- Honeycombing with or without traction

bronchiectasis- Absence of features listed as inconsistent with UIP pattern (see third column)

- Subpleural, basal predominance- Reticular abnormality- Absence of features listed as inconsistent with

UIP pattern (see third column)

- Upper or mid-lung predominance- Peribronchovascular predominance - Extensive ground glass abnormality (extent > reticular abnormality)- Profuse micronodules (bilateral, predominantly upper

lobes)- Discrete cysts (multiple, bilateral, away from areas

of honeycombing)- Diffuse mosaic attenuation/air-trapping (bilateral, in three or more lobes) - Consolidation in bronchopulmonary segment(s)/lobe(s)


• HONEYCOMBING IS KEY FEATURE but there is interobserver variability**

• CT DIAGNOSIS OF UIP is highly accurate (90-100%) PPV for UIP

• BUT up to 50% of UIP will not get confident UIP

**Watadani T. Interobserver Variability in the CT Assessment of Honeycombing in the Lungs. Radiology 2013

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UIP PATTERN

NSIP: NONSPECIFIC INTERSTITIAL PNEUMONIA

• Women, younger patients than UIP

• Histologic NSIP can occur with HIV, connective tissue disease, drug toxicity, hypersensitivity pneumonitis

• CELLULAR AND FIBROTIC NSIP

• CT FINDINGS

• Fine reticular and ground glass opacity

• Traction bronchiectasis

• Can be peribronchovascular with SUBPLEURAL SPARING

• HONEYCOMBING UNCOMMON and if present minimal

• OVERLAPS IN POSSIBLE UIP

Inconsistent with UIP Pattern (Any of the Seven Features)

- Upper or mid-lung predominance- Peribronchovascular predominance - Extensive ground glass abnormality (extent > reticular abnormality)- Profuse micronodules (bilateral, predominantly upper lobes)- Discrete cysts (multiple, bilateral, away from areas of

honeycombing)- Diffuse mosaic attenuation/air-trapping (bilateral, in three or more lobes) - Consolidation in bronchopulmonary segment(s)/lobe(s)

Ground glass does not exceed reticular changes: POSSIBLE UIP

PERIBRONCHOVASCULAR DISTRIBUTION AND SUBPLEURAL SPARING: NSIP




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SARCOIDOSISHONEYCOMBING DOES NOT MEAN UIP

CHRONIC HYPERSENSITIVITY PNEUMONITISInconsistent with UIP Pattern (Any of the Seven Features)



PROGRESSION OVER TIME: NSIP

POSSIBLE UIP DEFINITE UIP

DIAGNOSTIC ALGORITHM FOR IPF


• Exclusion of other known cause of ILD (exposures, connective tissue and drug toxicity)

• UIP Pattern on HRCT don’t need biopsy

• Combination of HRCT pattern and surgical lung biopsy.

• Discussion in multidisciplinary conference

SPECIAL TOPICS IN IPF

• SUPERIMPOSED PROCESS

• Acute Exacerbation of IPF

• Combined Pulmonary Fibrosis and Emphysema (CPFE)

• Lung Carcinoma

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ACUTE EXACERBATION OF IPF

• Acute (<30 days) deterioration without identifiable cause

• Exclude PE, heart failure, pneumonia

• Pathologically acute or organized diffuse alveolar damage

• May occur after surgeries/procedures

• High mortality (short term approx. 50%) and median survival of 22 days to 4.2 months

• CT shows new ground glass or consolidation

Acute Exacerbation

COMBINED PULMONARY FIBROSIS AND EMPHYSEMA SYNDROME (CPFE)

• No consensus definition

• Complicated by pulmonary hypertension

• More frequent than IPF alone

• Poor prognosis if present

• May have increased risk of acute lung injury (ARDS) after lung resection

• Higher risk of lung cancer

LUNG CANCER IN IPF

• Increased risk especially if smoker

• Prevalence 5-17%

• Autopsy: 3-40+ %

• Pulmonary fibrosis obscures and easily miss cancer

• Surgery: Worse prognosis and increased risk of exacerbation

• Will take patient off transplant list

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LUNG CANCERLUNG CANCER

LUNG CANCERSUMMARY

• Discussed importance of accurate diagnosis of Idiopathic Pulmonary Fibrosis

• Reviewed CT Terminology and Technique

• Discussed Criteria for classification of interstital lung disase into 3 categories

• UIP

• Possible UIP

• Inconsistent with UIP

• Reviewed special topics related to IPF (Acute exacerbation, CPFE and Lung Cancer)

REFERENCES

• Raghu G, Collar HR, Egan JJ et al. An Official ATS/ERS/JRS/ALAT Statement: Idiopathic Pulmonary Fibrosis: Evidence based Guidelines for Diagnosis and Manangement. Am J Resp and Crit Care Med, 2011 Mar 15; 183(6):788-824

• Hansell DM, Bankier AA, MacMahon H etal. Fleischner Society: glossary of terms for thoracic imaging. Radiology. 2008 Mar;246(3):697-722.

• Idopathic Pulmonary Fibrosis Clinical Research Network, Martinez FJ, de Andrade JA et al. Randomized trial of acetylcysteine in idiopathic pulmonary fibrosis. N Engl J Med. 2014 May 29;370(22):2093-101

• Collard HR, Ryerson CJ, Corte TJ et al. Acute Exacerbation of Idiopathic Pulmonary Fibrosis. An International Working Group Report. Am J Respir Crit Care Med. 2016 Aug 1;194(3):265-75

• Kusmirek JE, Martin MD, Kanne JP et al. Imaging of Idiopathic Pulmonary Fibrosis. Radiol Clin North Am. 2016 Nov;54(6):997-1014.

Documents

Chung-2.00 - CPD University of Toronto · • Collard HR, Ryerson CJ, Corte TJ et al. Acute Exacerbation of Idiopathic Pulmonary Fibrosis. An International Working Group Report. Am