ILO CLASSIFICATION OF STANDARD
CHEST RADIOGRAPHS OF
PNEUMOCONIOSES
Presenter :Dr Jyotsna Rayannavar
Chairperson : Dr K R Pravinchandra
INTRODUCTION
• 1930 First International Conference of Experts
on Pneumoconioses in Johannesberg radiological appearances and impairment of
lung functions.
• 1958 Geneva classification – radiological
appearances.
• Periodically revised 1968, 1971, 1980 & 2000.
SCOPE OF CLASSIFICATION
• Provides a means for describing and recording
systematically the radiographic abnormalities
in the chest provoked by inhalation of dusts.
• Used to describe radiographic abnormalities
that occur in any type of pneumoconioses.
• Designed for classifying the appearances seen
only on postero-anterior chest radiographs.
OBJECT OF CLASSIFICATION
• To codify the radiographic abnormalities of
the pneumoconioses in a simple, systematic
and reproducible manner.
• Neither defines pathological entities nor takes
into account working capacity
USES OF CLASSIFICATION
• Internationally for :
Epidemiological research
Screening and surveillance of those in dusty
occupations
Clinical purposes
• May lead to better international comparability
of data regarding pneumoconioses.
CLASSIFICATION
• ILO classification includes printed guidelines
and 2 sets of standard radiographs.
a. Complete set – 22 radiographs
b. Quad set – 14 radiographs.
• The reader compares the subject chest
radiograph with those of the standard set
• To classify the chest radiograph of a dust
exposed individual, 4 main points are to be
considered.
1. Technical quality
2. Parenchymal abnormalities
3. Pleural abnormalities
4. Symbols or other abnormalities
TECHNICAL QUALITY
•
•
•
•
Four grades : 1, 2, 3 & 4
Grade 1 : Good
Grade 2 : Acceptable, with no technical defect
Grade 3 : Acceptable, with some technical
defect but still adequate for classification
• Grade 4 : Unacceptable
PARENCHYMAL ABNORMALITIES
• Include :
Small opacities
Large opacities
• SMALL OPACITIES :
a. Profusion
b. Affected zones of the lungs
c. Shape
d. Size
• PROFUSION :
 4 categories : 0,1,2,3
 12 subcategories : 0/-, 0/0, 0/1
1/0, 1/1, 1/2
2/1, 2/2, 2/3
3/2, 3/3, 3/+
 Cat 0 refers to absence of small opacities & cat 3
to highest profusion.
 Compared with standard radiographs 0/0,1/1,2/2
& 3/3.
• AFFECTED ZONES :
Lung field is divided into 3 zones by horizontal
lines drawn at 1/3rd & 2/3rd of vertical distance
between lung apices & the domes of
diaphragm.
Upper / middle / lower
Small opacities profusion is determined in
affected lung zone.
• SHAPE AND SIZE :
2 shapes recognized : a) Rounded
b) Irregular
3 sizes determined in each shape.
Small rounded opacities : p, q, r
Small irregular opacities : s, t, u
Contd….
•
•
•
•
•
•
p : diameters upto 1.5mm
q : diameters 1.5 – 3 mm
r : diameters 3 - 10mm
s : widths upto 1.5mm
t : widths 1.5 – 3 mm
u :widths 3 – 10mm
• LARGE OPACITIES :
Opacity having the longest dimension
exceeding 10mm
3 categories : A, B, C
Category A : one large opacity having the
longest dimension up to 50mm or several
large opacities with the sum of their longest
dimensions not exceeding 50mm.
Contd….
Category B : one large opacity having the
longest dimension exceeding 50mm but not
exceeding the equivalent area of right upper
zone
Category C : one large opacity which exceeds
the equivalent area of the right upper zone
PLEURAL ABNORMALITIES
• Comprise of :
a. Pleural plaques (localized pleural thickening)
b. Costophrenic angle obliteration
c. Diffuse pleural thickening
• PLEURAL PLAQUES :
Localized pleural thickening of parietal pleura
Seen on diaphragm, on chest wall & at other
sites
If present on chest wall, recorded as in-profile
or face-on
Site, calcification and extent are to be
recorded
Contd…..
Extent is recorded only for plaques along the
chest wall
Extent is defined in terms of the total length
of involvement from with respect to
projection of the lateral chest wall (apex to
costophrenic angle)
1- one quarter of projection, 2- b/w one
quarter and one-half of projection, 3- more
than one-half.
• COSTOPHRENIC ANGLE OBLITERATION :
Present / absent
• DIFFUSE PLEURAL THICKENING :
Recorded only in the presence of, and in
continuity with, an obliterated costophrenic
angle
OTHER ABNORMALITIES/ SYMBOLS
• Relevant as they describe additional features
related to dust exposure and other aetiologies
• Each definition of symbols assumes an
introductory qualifying word or phrase such as
“changes indicative of”, or “opacities
suggestive of”, or “suspect”.
Contd….
• Symbols are :
 aa, at, ax, bu, ca, cg, cn, co, cp, cv, di,
 ef, em, es, fr, hi, ho, id, ih, kl, me,
 pa, pb, pi, px, ra, rp, tb, od
DESCRIPTION OF STANDARD
RADIOGRAPHS
• THE COMPLETE SET :
22 standard radiographs
2 : illustrate category 00 profusion of small
opacities
15: define small opacity profusion category
(1/1,2/2,3/3) and some of the shapes & sizes
of these opacities (p,q,r,s & t)
Contd…..
 3 :large opacities are shown (A,B,C)
Remaining 2 radiographs are composite
reproductions of sections from full-size chest
radiographs.
One depicts increasing profusion of irregular
small ‘u’ sized opacities
Other one illustrates various pleural
abnormalities
• THE QUAD SET :
Includes 9 of the most commonly used
standard radiographs from the complete set
Remaining 5 are composite reproductions of
quadrant sections from other radiographs in
the complete.
Normal chest radiograph showing normal anatomical features. Note the presence of
opacities that represent lymph nodes and blood vessels.
Chest radiograph of poor quality showing overlapping scapula (white arrows)
looking like pleural plaques on both right and left lung fields.
Silicotic chest radiograph showing a large opacity of category B (black arrows) on the right
upper zone. Numerous rounded opacities (q type) are present in all zones of the lung field.
Chest radiograph showing calcified diaphragmatic pleural plaques (white arrows)
and face-on plaques (blue arrows) bilaterally. In this film, pleural plaques can also be seen in
other site (mediastinal region bilaterally).
Chest radiograph of asbestos-exposed worker showing the presence of small irregular
opacities (of “t” type primarily and “s” type secondarily), predominantly on lower and
middle lung zones. The right upper lobe is also involved. The profusion is 2/3. In addition,
diffuse pleural thickening (DPT) is evident on the right and in-profile plaque on the left; also
note the abnormal cardiac size. The film quality is of grade 2 (scapula overlap).
REFERENCES
• Hunter’s Diseases of Occupations , 10th edition
• Guidelines for the use of the ILO international
classification of radiographs of
Pneumoconioses. Revised edition 2011,
Occupational Safety and Health Series 22.
• ILO Encyclopedia of Occupational Health and
Safety. 4th Edition Geneva, volume 2.
Thank you