HRCT of Idiopathic Interstitial Pneumonias

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HRCT OF IDIOPATHIC INTERSTITIAL PNEUMONIAS

Tadashi Allen, MD University of Minnesota Assistant Professor Diagnostic Radiology

10/29/2016

Disclosures

Genentech, Inc. Speakers Bureau

Outline

Definition of Terms

Non-Infectious Interstitial Lung Diseases: Idiopathic Interstitial Pneumonias Systemic Autoimmune Disease Hypersensitivity Pneumonitis Sarcoidosis Cystic Fibrosis Radiation Pneumonitis Drug Toxicity Emphysemas Pneumoconioses Langerhans Cell Histiocytosis Lymphangioleiomyomatosis Lymphangitic Carcinomatosis Amyloidosis Chemical Pneumonitis

Definition of Terms: Lexicon

Ground Glass Opacity

Traction Bronchiectasis

Honeycombing

Reticular Pattern

Nodular Pattern

Cysts

Interlobular Septal Thickening

Consolidation

Ground Glass Opacity: Example

1-2 mm cuts. 42 y/o female with PJP.

Traction Bronchiectasis: Example

Traction bronchiectasis refers to bronchial dilation due to fibrosis

Traction Bronchiectasis

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Honeycombing: Example

Honeycombing clustered air-filled, thick walled cysts

69 yo male, with UIP/IPF

Honeycombing

Honeycombing

Watadani et al. Radiology: Volume 266: Number 3—March 2013

5: 91%

5, definite honeycombing;4, probable honeycombing;

3, possible honeycombing; 2, probably no honeycombing; 1, definitely no honeycombing

4: 58%

2

3: 63%

1: 95%

Interobserver variability honeycombing

Reticular Pattern: Example

Nodular Pattern: Example

Nodular pattern

Cysts: Example

29 y/o female with pulmonary Langerhan’s Cell Histiocytosis

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49 y/o female with lymphangioleiomyomatosis

Interlobular septal thickening

86 y/o female short of breath

Interlobular septal thickening

Consolidation: Example

Areas of consolidation

30 y/o male influenza pneumonia with organizing pneumonia pattern

Major idiopathic interstitial pneumonias• Idiopathic pulmonary fibrosis• Idiopathic nonspecific interstitial pneumonia• Respiratory bronchiolitis–interstitial lung disease• Desquamative interstitial pneumonia• Cryptogenic organizing pneumonia• Acute interstitial pneumonia

Rare idiopathic interstitial pneumonias• Idiopathic lymphoid interstitial pneumonia• Idiopathic pleuroparenchymal fibroelastosis

Unclassifiable idiopathic interstitial pneumonias

REVISED ATS/ERS CLASSIFICATION OF IDIOPATHICINTERSTITIAL PNEUMONIAS: MULTIDISCIPLINARY DIAGNOSES

Am J Respir Crit Care Med Vol 188, Iss. 6, pp 733–748, Sep 15, 2013

Usual Interstitial Pneumonia (UIP): Idiopathic Pulmonary Fibrosis (IPF) Idiopathic pulmonary fibrosis is description of clinical

entity associated with morphologic pattern of UIP

Poor prognosis

CT features: Reticular pattern

Basal/peripheral predominance (apical basilar gradient)

Honeycombing

Traction bronchiectasis

Architectural distortion

Ground glass common but less predominant

IPF or UIP

Incidence: 6.8-16.3 per 100,000 persons based on health care claims in a large US health plan

Prevalence: 14-42 per 100,000 persons

Etiology: Unknown

Risk factors:

smoking strong risk factor (esp.>20 py)

Environmental exposures

Microbial agents

GERD

Genetic factors

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IPF: Diagnosis—ATS-ERS-JRS-ALAT 2000 consensus no longer valid

Major Criteria

Exclusion of other known causes of ILD, such as certain drug toxicities, environmental exposures, and connective tissue diseases

Abnormal pulmonary function studies that include evidence of restriction (reduced VC often with an increased FEV1/FVC ratio) and impaired gas exchange [increased AaPO2 with rest or exercise or decreased DLCO]

Bibasilar reticular abnormalities with minimal ground glass opacities on HRCT scans

Transbronchial lung biopsy or bronchoalveolar lavage (BAL) showing no features to support an alternative diagnosis

Minor Criteria

Age . 50 yr

Insidious onset of otherwise unexplained dyspnea on exertion

Duration of illness > 3 mo

Bibasilar, inspiratory crackles (dry or “Velcro” type in quality)

Am J Respir Crit Care Med Vol 161. pp 646–664, 2000Internet address: www.atsjournals.org

ATS-ERS-JRS-ALAT 2011 – IPFIdiopathic Pulmonary Fibrosis

Chronic progressive fibrosing interstitial pneumonia

idiopathic.

Occurs in older adults

Limited to the lungs

Associated with histopathologic and radiologic pattern of UIP

UIP Diagnosis requires:

Exclusion of other known causes of ILD including

domestic and occupational exposures,

connective tissue disease, and

drug induced lung toxicity

UIP pattern on HRCT without a surgical biopsy

Specific HRCT and biopsy patterns

UIP Diagnosis

Accuracy increases with multidisciplinary discussion between

Pulmonologists

Radiologists

Pathologists

(Whom are experienced in the diagnosis of ILD.)

UIP or IPF types of progression Increased respiratory symptoms

Worsening PFTs

Progressive fibrosis on HRCT

Acute respiratory decline

Death

UIP or IPF may have comorbid conditions including: Pulmonary hypertension

GERD

Obstructive sleep apnea

Obesity

Emphysema

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UIP: CT Imaging 1

53 y/o female biopsy proven UIP diagnosis IPF

UIP: CT Imaging 2

Possible UIP pattern on CT given lack of honeycombing. Biopsy UIP pattern. Dx IPF

UIP: CT Imaging 3

UIP: Extensive interstitial fibrosis with ground glass opacification and honeycombing

UIP: ATS 2011 HRCT Criteria

Am J Respir Crit Care Med Vol 183. pp 788–824, 2011

UIP: ATS 2011 HRCT


Multidisciplinary Discussion


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IPF Diagnostic algorithmNatural history of IPF

Rx IPF: Lung transplant

11/2013 2/2009

56 y/o male with IPF






NSIP: Clinical Features

Female to male ratio 2:1 5 yr survival 82.3% 2 subtypes: cellular and fibrotic Fibrotic NSIP accounts for most of the

mortality (8:1) Cough; Median duration 6 months Dyspnea; Median duration 7 months Prognosis is variable.


NSIP

Occurs as idiopathic condition

No longer “provisional” diagnosis

Can occur in variety of settings such as:

Collagen vascular disease

Hypersensitivity pneumonitis

Drug toxicity


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Cellular NSIP: CT Imaging

54 y/o female cellular NSIP

Fibrotic NSIP: CT Imaging

31 y/o male with fibrotic NSIP

NSIP: Additional Imaging NSIP: Additional imaging

NSIP: Reversibility with Treatment

NSIP post treatment 7 months f/u

NSIP pretreatment






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RB-ILD: Features 1

Histologic respiratory bronchiolitis is in 100% of cigarette smokers

When symptomatic, becomes RB-ILD

Most have mild symptoms, but some with severe hypoxemia, cough

Average smoking hx is 30 pack years

Patients are usually age 3rd or 4th decade

Disease reversible with smoking cessation and steroids

RB-ILD: Features 2

CT Characteristics

Imaging pattern similar to hypersensitivity pneumonitis

Centrilobular ground glass nodularity

Upper and mid-lung predominance

RB-ILD: CT Imaging 1

58 y/o male RB-ILD

RB-ILD: CT Imaging 2

Same pt

RB-ILD CT Imaging 3

Same pt






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DIP: Features

Primarily smoking related dz but is well described in nonsmokers

Some are related to extension of childhood DIP related to surfactant protein gene mutation

Survival: 70% at 10yrs

Can improve with steroids and smoking cessation

Not end spectrum of RB-ILD.

“Desquamative” is misnomer (Liebow and Carrington); characterized by macrophages filling alveoli. They considered to call “alveolar macrophage pneumonia”.

DIP: CT Imaging 1

43 y/o female DIP

DIP: CT Imaging 2DIP: CT Imaging 3

51 yo DIP

Mortality

Lynch DA, et al. Idiopathic interstitial pneumonias: CT features. Radiology 2005; 236: 10-21






http://radiology.rsnajnls.org/content/vol236/issue1/images/large/r05jl29g09x.jpeg

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(COP) Cryptogenic Organizing Pneumonia Histologic pattern is organizing pneumonia

Formerly referred to as (BOOP) bronchiolitis obliterans organizing pneumonia

Often confused with constrictive bronchiolitis (obliterative bronchiolitis), an airway disease.

(COP) Clinical features

Age: mean 55

No gender predilection

Mild dyspnea, cough, fever over a few weeks

Respiratory tract infection can precede symptoms along with antibiotic rx.

Or may be in CVD, or drug induced

Very responsive to corticosteroids – although relapses are frequent by 3 months

COP

47 yo female on MTx for RA 4 months apart

Atoll

Google images: Taiaro Atoll, French Polynesia, Pacific Ocean

COP: CT Imaging 2

32 yo AML COP and atoll sign

CT Imaging 2

Same pt

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(AIP) Acute Interstitial Pneumonia acute onset of symptoms

Age: mean 50 years

severe dyspnea with need for mechanical ventilation

h/o viral-like illness exists

Cigarette smoking not contributory

Treatment is supportive

(AIP) Clinical Features

Corticosteroids are effective in the early phase

Prognosis is poor

Mortality of 50% or more

Most patients who survive the acute phase progress to lung fibrosis

(AIP) Imaging features

Radiographic and HRCT findings are similar to ARDS

AIP patients more likely to have symmetric, bilateral distribution with lower lobe predominance.

(AIP) Imaging Features

Ground-glass

consolidation

Mild bronchialdilation

(AIP) Exudative phase 22-year-old

GGO

GGO

consolidation

RadioGraphics 2007; 27:595– 615 ●

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Fibrotic phase AIP

62 yo male AIP






(LIP) Clinical Features

Affects women more than men

5th decade of life

Slowly progressive dyspnea and cough

Occasionally fever, night sweats weight loss.

small percentage transform to malignant lymphoma

(LIP) Imaging Features

HRCT: Diffuse or lower lung predominance

ground-glass opacity, related to interstitial inflammation

Perivascular cysts: mid lung zones and result from air trapping due to peribronchiolar cellular infiltration

Centrilobular nodules and septal thickening

LIP: CT Imaging 1

52 yo female LIP and PCKD

LIP: CT Imaging 2

61 yo female Sjogren’s, LIP

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PleuroparenchymalFibroelastosis

High mortality 40%

Upper lung predominant

Disease progression 60%


Collagen vascular diseases Hypersensitivity Pneumonitis: Features

Also called extrinsic allergic alveolitis

Caused by repeated exposure to organic and chemical antigens

Pathogenesis: cell-mediated immunity (specifically T-helper cells)

Diagnosis: history of exposure, clinical signs/sxs, radiologic abnormalities, and histopathology

HP: Etiology

Radiographics 2009, November. Issue

HP: Radiographic Manifestations

HRCT: Poorly defined centrilobular nodules (<5mm)

predominantly in lower lobes Ground glass opacification Fibrosis: irregular linear opacities, traction bronchiectasis,

honeycombing Emphysema Air-trapping

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HP: CT Imaging 1 HP: CT Imaging 2

Acute Fibrinous Organizing pneumonia Can be idiopathic, or occur in CVD, HP, or

drug reaction, or with eosinophilic pneumonia.

HRCT findings of bibasilar opacities and consolidation.

Within the clinical spectrum between DAD, and OP.

Acute Fibrinous Organizing pneumonia

Summary

IIPs are classified based on histologic criteria, but correlate with imaging findings

In many cases, final diagnosis requires a multidisciplinary approach between clinicians, radiologists and pathologists

HRCT is indicated in all patients with IIP

UIP must be differentiated from all other IIPs because of its markedly poorer prognosis

END

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HRCT of Idiopathic Interstitial Pneumonias