1.
SOLITARY PULMONARY
NODULE
DR SABHILASH SUGATHAN

2.
DEFINITION
 A single well or poorly defined rounded opacity less than or Equal
to 3cm in diameter. Predominantly surrounded by lung
parenchyma, does not touch the hilum or mediastinum
 There should be no related abnormalities in the thorax such as
lymphadenopathy, pneumonia or atelectasis.
 Lesions larger than 3cm are called Pulmonary Masses(are treated
as malignancies until proven otherwise).

3.
Nodule measurements and technical
parameters for imaging
Image Production
In full inspiration
Nodules are viewed and measured in thin
slices(<1.5mm)using high spatial frequency
algorithm in order to avoid partial volume
averaging and to detect any fat or calcification
Measurement usually in Axial Plane.
Measurement should be in lung window.

4.
Measurement and Description
 <3mm – Micronodules(No need to
measure)
 3-10mm measured for risk
estimation. Average of short and long
axis diameter, rounded to the nearest
whole mm
 >10mm measured in both axis

5.
On seeing a SPM
 Important to secure old films to see whether a nodule is new ,
old , stable or growing over time
 Look for definitely benign features
 Asses for the risk of Malignancy
 Follow up

6.
MALIGNANT
VS
BENIGN

7.
NODULE CHARACTERISTICS
 SIZE
 LOCATION
 CALCIFICATION
 GROWTH
 MORPHOLOGY
 ENHANCEMENT

8.
BENIGN
 Shape and Edges
 Calcification
 Nodule with Macroscopic fat
 Peri fissural nodules
 Nodule with long term stability
 Small nodules in young patients

9.
Shape and Edges
 Round , oval shaped nodules with smooth / sharp margin

10.
1. Calcification
 Diffuse
 Central
 Laminated
 Pop- corn

11.
2. Nodule with macroscopic fat

12.
Shape
 polygonal shape and a three-dimensional ratio > 1.78 was a sign of benignity
A polygonal shape means that the lesion has multiple facets (multi-sided).
A peripheral subpleural location was also a sign of benignity in this study.
 The three-dimensional ratio is measured by obtaining the maximal transverse
dimension and dividing it by the maximal vertical dimension.
A large three-dimensional ratio indicates that the lesion is relatively flat, which is
a benign sign.

13.
3. Peri – fissural nodules
 Homogenous, smooth, solid, lentiform and triangular shaped
nodules either within / 1 cm of fissure or pleural surface and
measuring less than 10mm.

14.
4. Nodules with long term stability
 Solid nodules – 2 yrs.
 Sub solid nodules – 3yrs

15.
Contrast enhancement
 Contrast enhancement less than 15 HU has a very high
predictive value for benignity (99%).
After a baseline scan, 4 consecutive scans at 1 minute
interval are performed

16.
5. Small nodules in young patients
 Small < 8mm
 Young <35yrs

17.
History of risk factors

18.
Radiological predictors of malignancy
 Size
 Spiculation
 Upper lobe location
 Asymmetrical calcification
 Cavitation
 Sub solid appearance

19.
SIZE
 <4mm –1%
 4-7mm—3-7%
 8-10mm—15%
 >20mm—40%

20.
SPICULATION
Corona radiata sign - highly associated with malignancy –Spiculation due
to desmoplastic reaction around tumor

21.
Upper lobe location

22.
CAVITATION
 <4mm - benign
 4 – 16 mm – intermediate
 >16mm - malignant

23.
MALIGNANT CALCIFICATION
Eccentric Speckled

24.
Air Bronchogram sign
 commonly seen in malignant pulmonary
nodules.
 most commonly seen in BAC
(bronchoalveolar cell carcinoma) and
adenocarcinoma.
 airbronchogram seen as a linear lucency
(broad arrow) and as a more cystic
lucency (small arrow) due to the fact
that the bronchus is seen en face.

25.
SUB - SOLID NODULE

26.
PULMONARY
NODULES
SUB SOLID
(SSN)
PURE GROUND
GLASS NODULE
(pGGN)
PART SOLID
NODULE (PSN)
SOLID

27.
Chance of malignancy
 Solid –7%
 Part solid –63%
 Ground glass nodule—17%

28.
Pure GGN

29.
Differential diagnosis of sub solid nodules
 Hemorrhage
 Infection
 Organizing pneumonia
 Focal fibrosis

30.
 Adeno carcinomas of lung –30-35% of primary lung
tumours and the subset bronchoalveolar carcinoma
commonly present as SSN
 The term BAC is now replaced by its histological
subtypes which has characteristic CT finding

31.
AAH(Atypical adenomatous hyperplasia)
 CT findings : <5mm Ground
Glass opacities

32.
AIS (Adenocarcinoma InSitu)
 >5mm diameter
 CT findings : ground glass
opacities with small solid
components

33.
MIA(Minimally invasive Adenocarcinoma)
 CT findings : part solid
nodule – ground glass with
<5mm solid components

34.
Invasive Adenocarcinoma (non mucinous or
mucinous)
 CT findings: part solid with
>=5 mm or solid

35.
Follow up of solid nodules (Fleishchner
Society guidelines)
 Low risk group
o <6mm –no follow up
o 6-8mm—CT at 6- 12months
 High risk group
o <6mm –optional CT after 12 months , consider CT at 18-24
o 6-8mm—CT at 6 - 12 months ----follow at 18 - 24months

36.
Nodule >8mm
 All Cases – CT at 3months , PET CT followed by CT guided biopsy/
Excision biopsy

37.
Follow up of SSN(Fleishchner Society
guidelines)
 Recommendation 1 : GGN <6mm – no followup
 Recommendation 2 : GGN>6mm – follow up after 3 months, then yearly
followup for 5 yrs
 Recommendation 3 : PSN –considered malignant if it remains stable at 3
months and if increases in size.
if solid component <6mm likely to be AIS or MIA(follow R2)
if solid component >6mm biopsy if not a surgical candidate

38.
THANK YOU.