- Solitary pulmonary nodules (SPNs) are round opacities less than 3cm in the lungs. Differentiating benign from malignant SPNs is important to avoid unnecessary procedures for benign nodules and ensure early treatment of malignant ones. - CT is commonly used to characterize SPNs based on size, margins, the presence of calcification, fat, cavitation, and air bronchograms. Malignant SPNs often have irregular margins, are larger than 3cm, and show air bronchograms, while benign SPNs frequently have smooth margins and calcification. - Dynamic contrast-enhanced CT can provide additional information on enhancement and washout patterns to differentiate benign from malignant nodules. For in

1. Solitary Pulmonary Nodule
- Dr. Bhanupriya Singh.
JR-1
Radiodiagnosis
1

2.  Round or oval opacity
 Less than 3cm in dimeter
 Completely surrounded by lung parenchyma
 Not associated with lymphadenopathy, atelectasis or
pneumonia
 The leison >3cm is called mass
2

3.  SPN is found in 1-2% of all CXR
 No racial difference in the prevalence and
incidence of malignant nodules
 Geographic variations in the incidence of benign
lesions, especially infectious granulomas.
 No sex difference in incidence
 Solitary nodules can occur at all age
3

4.  Differentiation of benign from malignant lesion
 Early identification and resection of malignant
nodules
 Avoid thoracotomy in patients with benign nodules
 Cost-effective work-up
4

5.  Most SPNs are asymptomatic. The main goal of
investigating an SPN is to differentiate a benign lesion
from a malignant lesion as soon and as accurately as
possible.
 Important features in the patient history include the
following:
 Age - Risk of malignancy increases with age
 Risk of 3% at age 35-39 years
 Risk of 15% at age 40-49 years
 Risk of 43% at age 50-59 years
 Risk of greater than 50% in patients older than 60
years
5

6.  Smoking history
 Prior history of malignancy
 Travel history - Travel to areas with endemic
mycosis (eg, histoplasmosis, coccidioidomycosis,
blastomycosis) or a high prevalence of
tuberculosis
 Occupational risk factors for malignancy -
Exposure to asbestos, radon, nickel, chromium,
vinyl chloride, and polycyclic hydrocarbons
 Previous history of tuberculosis or pulmonary
mycosis
6

7. Congenital Traumatic
Bronchogenic cysts hematoma
AVF
Bronchial atresia
Infective Neoplastic
TB, round pneumonia bronchogenic ca
Fungal carcinoid
Hydatid hamartoma
Septic embolus metastases
Miscellaneous lymphoma
Wegeners granulomatosis adenoma
RA
Amyloidosis
Rounded atelectasis
7

8.  40% of spn are malignant, with other common lesion
being granuloma and benign leison
 Benign
 80% infectious granulomas
 10% hamartomas
 10% non-infectious granulomas, benign tumours'
 Malignant
 25% metastatic
 75% bronchogenic carcinoma and carcinoid
8

9. Extra thoracic artefacts
 Cutaneous masses – nipple, lipoma ,NF
 Bony lesions – island, healing #, sclerotic lesion
 Pleural tumors / plaques
 Encysted pleural effusion
 Pulmonary vessels - en face
9

10.  PLAIN radiography
 CT
 NCCT, CECT, WITH PHANTOM
 MR WITH GD-DTPA
 PET WITH FDG-F18
 PET CT
 FNAC/BIOPSY
10

11. TWO ISSUES
Lesion detection
Lesion characterization
benign versus malignant
11

12.  Pick up depends upon experience
 Over reading/ under reading
 High Kv – better rate of detection
 Digital radiographs- allow manipulation on a computer
monitor
Always compare current radiographs
with previous radiographs
12

13.  SPNs are discovered first as incidental findings on chest
radiographs.
 The first step is to determine whether the nodule is
pulmonary or extra pulmonary.
 A lateral chest radiograph, fluoroscopy, or CT of the chest
often helps determine the location of the nodule.
 >8-10 mm Nodules are identifiable by chest radiographs.
 Occasionally, SPNs can be visualized at 5 mm in diameter.
13

14. EXTRA PULMONARY
INTRA PULMONARY
14

15. 15

16. 16

17.  Size
 Margin
 Calcification
 Fat
 Cavitation
 Air bronchograms or bubbly lucencies
17

18. SIZE
Likelihood ratio of malignancy in SPN:
< 1 cm ---------- 0.52
1.1-2 cm ---------- 0.74
2.1-3 cm ---------- 3.7
> 3 cm ---------- 5.2
SPN > 4 cm -----bronchial ca except Hydatid, abscess,
wegener’s
SPN < 2 cm ------80% benign
15% of malignant ----<1cm
18

19. MARGIN
 Small nodule with smooth margin suggestive of benign
but not diagnostic of benign leison
 Lobulated contour
 Irregular margin typical malignant leison
 Spiculating margin
 Adjacent tiny nodules, called satellite nodules, may mimic
the appearance of a lobulated and the presence of these
nodules is strongly associated with benignity
19

20. 20

21. 21

22. Spiculated nodule
MALIGNAN
T
Irregular contour
Spiculated margin
Bronchus leads to it
LOBULATED MARGIN
22

23.  Suggestive of benign SPN
 – Central, solid
 – Laminated
 – Popcorn -1/3 rd of hamartoma
 – Diffuse
 Suggestive of Malignant SPN
 – 6-14% of malignant nodules are calcified on CT
 – Eccentric
 – Stippled
23

24.  A stippled appearance or psammomatous calcification
can be seen in SPNs that are metastases from mucin-
secreting tumors such as colon or ovarian cancers
• Dense foci of calcification or be entirely calcified,
with a pattern resembling that of benign Disease can be
seen in carcinoids, metastatic osteosarcomas,and
chondrosarcomas
24

25. Central = granuloma
Nodule completely calcified = granuloma
Target = histoplasmosis
Popcorn = hamartoma
25

26. 26

27. 27

28. ECCEN
28

29. 29

30.  SPNs with irregular-walled cavities thicker than 16 mm tend to
be malignant
 Benign cavitated lesions usually have thinner, smootherwall
 Up to 15% of lung cancers form a cavity, but most are larger
than 3cm in diameter
30

31. THICK WALLED THIN WALLED
31

32.  Air bronchograms are seen more commonly in
pulmonary carcinomas than in benign nodules
 Air bronchograms were seen in approximately
30% of malignant nodules but in only 6% of
benign nodules
 Air bronchograms is due to desmoplastic reaction
to the tumour that distort the airway
32

33.  50% of hamartomas have fat
 30% of hamartomas have calcification (popcorn
appearance)
 Middle-aged adults, slow growth ,90% in intra
pulmonary and within 2cm of pleura
 fat is present in the nodule , hamartoma or lipoma
become most likely cause , Metastasis from lipo
sarcoma , RCC ,may occasionally contain fat
 In patient without prior malignancy , focal attenuation
(-40to-120)is reliable indicator of hamartoma
33

34. 34

35.  tuberculoma:
 most common in upper lobe
 well defined and lobulate ,
 calcification frequent , 80% have satellite leison
 Cavitation is uncomman
 Histoplasmosis
 Most frequent in lower lobe
 Well defined / seldom larger than 3cm
 Calcification common and central –target appearance
 Cavitation are rare
35

36.  HYADIT CYST
 Most common right lower lobe
 Common in endemic area
 Well defined , 1-10 cm in size
 Rupture result in –water lilly sign
36

37.  AVM:
Well defined and lobulated- Bag of worm appearence
dilated feeding arteries and draining vein may be visible
66% are single, calcification is rare
 Hematoma
peripheral ,smooth and well defined
slow resolution over several weeks
 Pulmonary infarction
Most frequent in lower lobe
wedge shaped area of consolidation can be identified abutting the
pluera , small u/l or b/l pleural effusion is seen
37

38. AVM WITH FEEDING VESSELS
38

39.  Pulmonary sequestration
 usually more than 6cm in diameter
 2/3rd in left LL ,1/3rd in rt LL
 well defined round or oval leison
 Confirmed by aortography and venous drainage is via
pulmonary vein or bronchial vein
 Bronchogenic cyst
 well defined ,round or oval in shaped ,smooth wall
 2/3rd are intrapulmonary , located medial 1/3rd of LL
 Peak incidence in 2nd and 3rd decade of life
39

40.  standard CT examination without contrast
material enhancement may be performed
 Ensure there are no other findings, such as
additional nodules lymphadenopathy, pleural
effusion, chest wall involvement, or adrenal
mass.
 concerns about radiation dose to the patient,
subsequent follow-up CT may be limited to the
nodule location.
40

41.  Thin-section CT scans obtained through the nodule
provide information regarding nodule size (by using
diameters from the largest cross-sectional area or volume
measurement) attenuation, edge characteristics, and the
presence of calcification,cavitation, or fat .
 Sequential thin-section CT (1 3-mm section width)
performed through the entire nodule with a single breath
hold and without contrast
41

42.  Absence of detectable growth over a 2-year period of
is a reliable criterion for establishing that a pulmonary
nodule is benign
 Difficult to detect growth in small (< 1cm) nodules.
 To overcome this limitation,
 growth rate of small nodules be assessed using serial
volume measurements rather than diameter
 Computer-aided 3D quantitative volume measurement
methods have been developed and applied clinically
 All these volumetric methods are focused on solid
pulmonary nodule
42

43. Volume is doubled if diameter has increased by at least
1.25 times in at least 2 dimensions
< 30 days and > 465 days - benign
30 – 465 days - malignant
 not for lesions < 5mm
 many lesions are not completely spherical
 Hemorrhage into a lesion can increase the volume
dramatically
 bronchial carcinoids and BAC long doubling times
43

44. 44

45. 45

46. 25 MONTHS LATER
DOUBLING TIME = 1375 DAYS
BRONCHIOALVEOLAR CARCINOMA
46

47.  The leison should be atleast 10mm
 Contrast enhancement is directly related to the
vascularity and blood flow
 Nodule examined 3mm collimation before and after
administration of contrast
 1 min interval upto 4min after administration of contrast
 Nodule enhancement= peak mean – base line
attenuation
47

48.  Early cut off point for differention of benign from
malignant nodule - 15H enhancement
 Early study more focus on early phase of dynamic
CT .this studies are more sensitive but less specific
 Overlap was found between malignant and benign
nodules for example, active granulomas and benign
vascular tumors
48

49.  FALSE POSITIVE:
 active infection
 active inflammation
 FALSE NEGATIVE
 Broncho alveolar ca
 Leison with central necrosis
 cavitary leison
49

50.  Evaluation of SPNs by analyzing combined
wash-in and washout characteristics on dynamic helical
CT allows more precise evaluation ,sensitivity and
specificity more than 90%
BENIGN
- wash in < 25H enhancement
- wash in >25H enhancement with a wash out of > 35H
- washin of >25H and Persistent enhancement without
wash out
MALIGNANT
wash in of>25H and wash out 5-31H enhancement
50

51. DYNAMIC CECT
MALIGNANT – METASTATIC MELANOMA
51

52.  Special circumstances – contrast allergy etc
 Not routinely used due to cost factor
 CT is as good
52

53. TISSUE DIAGNOSIS
 TTNA- TRANS THORACIC NEEDLE
ASPIRATION
24 G needle
 CORE BIOPSY
 BRONCHOSCOPIC BIOPSY
 VATS
53

54. indication
 Poor candidates for surgery because of comorbidities,
 FNAB can be used to diagnose malignancy and determine the
histologic type of malignancy. In patients who are candidatesfor
surgery
 FNAB may be used to diagnose benign disease, thus obviating
surgery
 Contraindications
 inability of the patient to cooperate
 . Other relative contraindications
 bleeding diathesis,
 previous pneumonectomy, severe emphysema,
 severe hypoxemia,
 pulmonary artery hypertension,
 nodules which successful biopsy cannot be performed
54

55.  FNAB has a sensitivity of 86.0% anda specificity of
98.8% in the diagnosis of malignancy
 Sensitivity of FNAB is also lower (12%) in patients
with lymphoma, and core biopsy (sensitivity,62%) is
recommended
 Nodules that are in the lower lobes or adjacent to the
heart may be difficult to access because of varying
breath holds and diaphragmatic and cardiac motion
55

56.  When the FNAB sample is interpreted as malignant or
specific benign condition is, further workup based on
diagnosis.
 when a nonspecific benign condition is diagnosed,
further evaluation is required
 The most common complications of
FNAB are pneumothorax and hemorrhage
56

57. PET with FDG-F18
 PET/CT may be selectively performed to characterize
SPNs when dynamic helical CT shows inconsistent results
between morphological and , hemodynamic characteristics
 PET 18F-FDG is accurate ,noninvasive diagnostic test
with sensitivity of 88-96% and specificity of70-90% of
malignant nodule
 PET-CT provide more anatomical detail than PET alone
or CT alone
 Increased uptake of 18F-FDG –MALIGNANT
 Decreased uptake - BENIGN
 False positive- infection /inflammation
 False negative –BAC, carcinoid
 Best test for leison >1cm leison
57

58.  Fasting to enhance FDG uptake by tumor cells
 Blood glucose < 150mg% (GLUT)
 No C/I to FDG
 10 mCi injected i/v
 Imaging at 60 min after injection
 SUV = tracer in tissue
injected dose / pt wt
58

59. CT FDG PET
LUNG
CANCER 59

60. 60

61. 61

62. CLINICAL BENIGN MALIGNANT
Age < 35 yrs >35 yrs
h/o smoking - +
Exposure to
TB
+ -
Exposure to
carcinogens
- +
Primary
lesion
elsewhere
- +
62

63. Chest X ray BENIGN MALIGNANT
size < 3cm >3 cm
location Not specific Upper lobes
margins smooth Spiculated
calcification Central,
diffuse,
laminated,
popcorn
Eccentric/
stippled
Growth pattern Stable for 2 yrs Presence of
growth
Doubling time < 30 d or > 465
days
30 – 465 days
Satellite nodule more less
63

64. CT BENIGN MALIGNANT
Fat + -
Bubble like
lucencies
uncommon Common
Enhancement < 25 HU > 25HU
densitometry > 200 HU < 200 HU
64

65. BAYESIAN ANALYSIS
 For evaluation of indeterminate nodules
 Probability of malignancy calculated from
clinical profile and imaging features
 Likelihood ratios LR
 LR = no of malignant nodules with sp feature /
no of benign nodules with same feature
LR=1 ------ 50% chance malignancy
LR<1 ------ benign
LR>1 ------ malignant
65

66.  Patient age
 Smoking history
 Previous malignancy
 Size of the nodule
 Edge characteristics Nodule features
 Calcification pattern
 Symptoms
 Environmental exposures
66

67. FEATURE LR
Spiculated margins 5.54
Size > 3 cm 5.23
Age > 70 yrs 4.16
Malignant growth
rate
3.40
smoker 2.27
Upper lobe 1.22
67

68. Size < 1cm 0.52
Smooth margins 0.30
30 – 39 yrs 0.24
No h/o smoking 0.19
20 – 29 yrs 0.05
Benign calcification 0.01
Benign growth rate 0.01
68

69.  ≥ 25 H wash-in and 5–31 H washout
 lobulated margin
 spiculated margin
 absence of a satellite nodule
AJR,188,JAN 2007 69

70. AJR,188,JAN 2007
70

71. NODULE SIZE
IN MM
LOW RISK PATIENT HIGH RISK PATIENTT
<4MM NO FOLLOWUP NEEDED IN ITIAL CT AT 12 MONTH,
IF UNCHANGED, NO
FOLLOWUP
4-6MM IN ITIAL CT AT 12 MONTH, IF
UNCHANGED, NO FOLLOWUP
INITIAL CT AT 6TO12
MONTH THEN AT 18 -24
MON IF NO CHANGE
6-8 MM INITIAL CT AT 6TO12 MONTH THEN
AT 18 -24 MON IF NO CHANGE
INITIAL CT AT 3 TO 6
MONTH THEN AT 9 TO 12
MON AND 24MON IF NO
CHANGE
>8MM CT FOLLOWUP 3, 9, 24
MON/DYNAMICCT/PET CT/BIOPSY
CT FOLLOWUP 3, 9, 24
MON/DYNAMICCT/PET
CT/BIOPSY
MacMahon, H. et al. Guidelines for management of small pulmonary nodules detected on CT scans:
A statement from the Fleischner Society. Radiology 2005; 237: 395-400
DO not use in pts <35y/o; h/o malignancy or in pts w fever.71

72.  CT screening, has increased the detection rate of small
nodular lesions,
 In providing information about morphologicand
hemodynamic characteristics with high specificity and
reasonably high accuracy,
 CT scan can be used for the initial assessment of SPNs.
 PET/CT is more sensitive for detecting malignancy than
dynamic helical CT, and all malignant nodules may be
potentially diagnosed as malignant by these two techniques.
72

73.  PET/CT may be selectively performed to
characterize SPNs when dynamic helical CT
shows inconsistent results between
morphologicand hemodynamic characteristics
 Serial volume measurements are currently the
most reliable methods for the tissue
characterization of subcentimeter nodule
73

74. THANKS
74

75. 75

76. 76

77. 77

78. 65 yr old with pleuritic chest pain PULMONARY INFARCT
78