solitary pulmonary nodule

1. Dr . ARUN KUMAR

2. DEFINITION
• Round or oval opacity smaller than 3 cms in
diameter
• Completely surrounded by lung parenchyma
• No atelectasis
• No lymphadenopathy
• No pneumonia

3. Lesions more than 3cms are termed as masses.
SPN MASS

4. CLASSIFICATION ON CT
• Solid-Soft tissue attennuation
• Sub solid-Ground glass attenuation
• Soft tissue with ground glass
attenuation

5. DIFFERENTIAL DIAGNOSIS FOR SOLID
SPNS
CAUSE CONDITION
Neoplastic (malignant) Primary lung malignancies (non–small cell,
small cell, carcinoid, lymphoma), solitary
metastasis
Benign Hamartoma, arteriovenous malformation
Infectious Granuloma, round pneumonia, abscess,
septic embolus
Noninfectious Amyloidoma, subpleural lymph nodule,
rheumatoid nodule, Wegener
granulomatosis, focal scarring, infarct
Congenital Sequestration, bronchogenic cyst, bronchial
atresia with mucoid impaction

6. SUB SOLID SPN
TYPE OF CAUSE CONDITION
Malignant LUNG
ADENOCARCINOMA;
Metastasis from
melanoma, renal cell
carcinoma, and
Adenocarcinoma of the
pancreas, breast, and
gastrointestinal tract
Lymphoproliferative
disorders
Benign Organizing pneumonia,
Focal interstitial fibrosis,
Endometriosis

7. EVALUATION
• Clinical
• Radiological

8. CLINICAL EVALUATION
• History of smoking,
• Age over 40,
• Occupational exposures (e.g.,
asbestos),
• Lung fibrosis,
• Coexisting chronic obstructive
pulmonary disease (COPD) and
emphysema,
• Family history of lung cancer

9. • Recent travel history,
• Positive skin test for tuberculosis (TB) or
fungus, or
• Presence of other diseases (e.g.,
rheumatoid arthritis)

10. RADIOLOGICAL EVALUATION
• Chest x ray
• CT scan
• FDG-PET
• BIOPSY
• Newer modalities-Dynamic MR imaging
DW MRI
• FOLLOW UP

11. MORPHOLOGICAL EVALUATION
• Size
• Location
• Edge Appearance
• Calcification
• Attenuation
• Air Bronchograms and
Pseudocavitation
• Cavitation
• Satellite Nodules
• Feeding Vessel Sign

12. • Fat
• Water Density
• Contrast Enhancement
• Hemodynamics
• Growth

13. SIZE
• The smaller the nodule the more likely it
is
benign.
• Limited use in sub solid SPN
Size (cm) LikelihoodRatio
• 3.0 5.23
• 2.1–3.0 3.67
• 1.1–2.0 0.74
• 1.0 0.52

14. SIZE INTERPRETATION
< 3mm 99.8% benign
4-7mm 99.1%benign
8-20mm 82%benign
>20mm 50%benign
>30mm 7%benign

15. LOCATION
• Attached nodule – length of contact surface of nodule
>50% of nodule diameter or major part of non spherical
nodule is attached to fissure /pleura/vessel implies
benignity.
• BENIGN-Evenly distributed through lung
• MALIGNANT-R>L;UL>LL
Adenocarcinomas – Peripheral
Small cell carcinomas- Central
Metastasis- Peripheral/sub pleural
Associated with fibrosis- Lower lobes

16. EDGE
• Benign lesions - smooth, sharply defined edge .
• Malignant nodules -ill-defined, irregular, lobulated, or
spiculated margin(corona radiate and corona maligna
)
• SHARPLY MARGINATED
Granuloma
Hamartoma or benign tumor
CARCINOID TUMOR
METASTASIS
• Spiculated (corona radiata) –growth of cells along
interstitum
Bronchioloalveolar carcinoma
GRANULOMA OR FOCAL SCARRING

17. Hamartoma presenting as a sharply defined, round nodule. A. Chest
radiograph shows a round nodule (arrows) in the right upper lobe. B.
CT shows the nodule (arrow) to be rounded in shape and sharply
marginated. Slight lobulation may be seen with hamartomas

18. Solitary metastasis from a head and neck carcinoma. A left upper
lobe nodule (arrow) is smooth and sharply defined on CT. This
appearance is common with metastases.

19. Adenocarcinoma. HRCT shows an irregular, spiculated nodule with
multiple
pleural tails. Air bronchograms are visible within the nodule

20. • PLEURAL TAIL SIGN-linear opacity is seen extending from the
edge of a lung nodule to the pleural surface
• CT HALO SIGN-halo of GGO surrounding a nodule.
• Represents hemorrhage,inflammation,infiltration
Fungi: invasive aspergillosis, candidiasis, coccidioidomycosis
Bacteria: tuberculosis, Nocardia, Legionella
Viruses: cytomegalovirus, herpes
Pneumocystis jiroveci (P. carinii)
Bronchiolitis obliterans with organizing pneumonia
Wegener's granulomatosis
Infarct
Metastatic tumor-
angiosarcoma,choriocarcinoma,osteosarcoma
Kaposi's sarcoma

21. Halo sign
a) invasive aspergillosis. HRCT in a young patient with leukemia and
granulocytopenia shows a dense left lower lobe nodule surrounded by a halo
(arrows) of ground-glass opacity. In patients with invasive aspergillosis, the halo
represent hemorrhage surrounding a septic infarction
b) bronchioloalveolar carcinoma, the halo represents the presence of lepidic tumor
growth

22. • Reverse halo sign-ATOLL SIGN central area of
ground glass attenuation surrounded by a halo or
crescent of consolidation
• Seen in CRYPTOGENIC ORGANIZING
PNEUMONIA
Paracoccidioidomycosis,
• Tuberculosis,
• Lymphomatoid granulomatosis,
• Wegener granulomatosis,
• Sarcoidosis
• Lung cancer after radiotherapy

23. Reverse halo sign after radiofrequency ablation of a pulmonary metastasis
in a 63 year-old man with pancreatic cancer who previously underwent left
upper lobectomy. (a) CE CT image shows a left-lower-lobe metastasis
(arrow).
(b) CECT image obtained 1 month after radiofrequency ablation shows the
treated metastasis (arrow), which now has mixed attenuation, surrounded
by a ground glass opacity (*) and a well-circumscribed rim of consolidation
(arrowheads)

24. CALCIFICATION
• Most important characteristic feature
• Best detected on HRCT
• The presence of calcium in an SPN increases its
chances
of being benign
a. Benign
b. Indeterminate

25. BENIGN PATTERN
a. Homogeneous calcification
b. Dense central (“bull's-eye”)
c. Concentric rings of calcium (“target”)
d. Conglomerate foci of calcification involving a
large part of the nodule (“popcorn”)
CARCINOID TUMOR
MUCINOUS ADENOCARCINOMA.
METASTASES FROM OSTEOGENIC
SARCOMA OR CHONDROSARCOMA

26. a)Homogeneous calcification. Dense
and uniform calcification of a small right
upper lobe nodule (arrow) is typical of a
benign lesion, usually a tuberculoma
b)Concentric or “target” calcification
(arrow). One or more rings of calcium
may be seen. This pattern is typical
of a histoplasmoma

27. a)Dense central or “bull's-eye”
(arrows) .This is typical of
histoplasmoma or hamartoma
b)Multiple confluent nodular foci of
calcification (“popcorn” calcification;
arrow) This appearance is typical of
hamartoma and corresponds to
calcification of cartilage nodules

28. INDETERMINATE
PATTERN
• Stippled
• Eccentric
• Amorphous
Eccentric calcification in an
adenocarcinoma. A lobulated mass
shows a small focus of eccentric
calcification (arrow).

29. • Dual-energy CT, in which 80- and 140-kV images
are simultaneously obtained, measurement of CT
attenuation values obtained at different kilovolt
peaks may be used to identify areas of calcium
and iodinated contrast material.
• A multicenter trial showed that the use of
unenhanced dual-energy CT to evaluate changes
in attenuation values at 140 and 80 kVp is not
reliable for differentiating benign and malignant
nodules with 3-mm sections and differing
acquisitions for both kilovolt potentials

30. ATTENUATION
• Soft tissue attenuation in solid SPN
• GGAN , GGAN + Soft tissue attenuation in sub solid SPN
• Classification of Nonmucinous Forms of Lung Adenocarcinoma &
CT Features of Subsolid Nodules(2011 IASLC,ATS&ERS )
• Atypical adenomatous hyperplasia GGAN
Adenocarcinoma in situ GGAN with a possible
solid component
Minimally invasive adenocarcinoma GGAN, partly solid
nodule
Lepidic-predominant adenocarcinoma Partly solid nodule,
solid nodule
Invasive adenocarcinoma Partly solid nodule, solid
nodule

31. • Mean nodule attenuation number could be used to
differentiate among AAH (-609 HU), BAC (-450 HU), and
invasive adenocarcinomas (-319 HU).
• Although there is currently no standard CT methodology
for quantifying the soft-tissue component of SSNs, direct
correlation of the soft-tissue component with the degree
of invasion or aggressiveness of subsolid
adenocarcinomas and patient prognosis and survival has
been reported
• Honda et al (45) reported that a ratio of the largest tumor
dimension on images obtained with soft-tissue window
settings versus that on images obtained with lung
window settings of 50% or less indicated an “air-
containing type,”(AIS) a ratio of more than 50% indicated
a “solid type” lesion(INVASIVE ADENOCARCINOMAS)

32. AIR BRONCHOGRAM &
PSEUDOCAVITATION
• Presence implies malignancy.
• Most typical of adenocarcinoma or bronchioloalveolar carcinoma.
• Small air-filled cystic areas in the tumor (so-called pseudocavitation),
or small cavities have the same significance as air bronchograms.
• Other causes
Conglomerate mass
Focal pneumonia
Infarction
Rounded atelectasis
Bronchiolitis obliterans with organizing pneumonia
Lymphoma
Lymphoproliferative diseases
Mycetoma (may mimic a bronchogram

33. CAVITATION
• Both benign & malignant show cavitation.
• The thickness &nature of the wall of a cavity serves
as an indicator of its likelihood of being malignant.
• If the thickest part of the wall is less than 5 mm, 95%
are benign.
• Nearly 92% of cavities with a wall measuring more
than 15 mm in its thickest portion are malignant.
• 51% of cavities with a wall 5 to 15 mm in thickness
are benign.
• Cavitary malignant lesions tend to have a thick,
nodular wall ; benign lesions often have a thin,
smooth wall

34. Characteristic LikelihoodRatio
Cavity wall thickness (mm)
16 37.97
4–16 0.72
4 0.07
a
c
Cavitary carcinoma. A. Plain radiograph showing a
cavitary left lung mass that represents a squamous cell
carcinoma. B. Cavitary squamous cell carcinoma shown
at two levels. The wall of the cavity is irregular, with
several thick nodular regions (white arrow). The cavity
contains an air-fluid level (black arrows). This is
uncommon in malignancy and may represent
hemorrhage or infection. C. Cavitary adenocarcinoma
shown on HRCT in six contiguous scans. The nodule
contains an irregular cavity; is irregular and lobulated in
shape, notched, and spiculated; and is associated with
pleural tails. It also contains several air bronchograms

35. • Air fluid level-a mass or nodule may be present
within the cavity. Air outlining or capping the
superior aspect of the mass results in a crescent-
shaped collection of air, termed the “air-crescent”
sign
The axial CT shows a nodule (black arrow) with a
Crescent of air(white arrow) in aspergilloma

36. • Air fluid level- The presence of an air-fluid level in a patient with
a cavitary SPN tends to indicate a benign lesion, particularly
lung abscess .
• Any infected cystic or cavitary lesion may be associated with an
air-fluid level.
• An air-fluid level is uncommon in a cavitary carcinoma, but may
be seen in the presence of intracavity hemorrhage or
superinfection .
CT scan of a lung
abscess

37. SATELLITE NODULE
• Small nodules seen adjacent to a larger
nodule or mass & predict benign lesion
• Most common with granulomatous
diseases& infections such as TB
• Only a small percentage of carcinomas are
associated with satellite nodules.
• Galaxy sign in sarcoidosis
Tuberculosis. A right upper lobe nodule is
associated with satellites (arrows). This
appearance is most typical of a benign
process but sometimes is seen with
carcinoma

38. FEEDING VESSEL
SIGN
• Small pulmonary artery is seen leading directly to a
nodule
• Most common with metastasis, infarct, and
arteriovenous fistula.
• Less common with primary lung carcinoma or
benign lesions such as granuloma.
Metastatic nasopharyngeal carcinoma.
Multiple nodules (arrows) are associated
with a feeding vessel.

39. FAT
• The presence of fat in an SPN may be diagnosed
accurately only on HRCT.
• On HRCT, fat can be accurately diagnosed if low
CT numbers are seen (-40 to -120 HU)..
• The presence of fat within a lung nodule is
sufficient for calling it benign, although follow-up is
appropriate.
HAMARTOMA
LIPOMA
LIPOID PNEUMONIA
TERATOMA
LIPOSARCOMA
RCC

40. Hamartomas containing fat in three patients. Focal areas
of low-attenuation fat are visible within the nodules
(arrows). The nodules are rounded and sharply defined

41. WATER
DENSITY
• Benign cystic lesions, such as pulmonary
bronchogenic cyst, sequestration, congenital cystic
adenomatoid malformation (CCAM), or a fluid-filled
cyst or bulla , occasionally may be diagnosed on CT
by their water attenuation (0 HU)
Pulmonary bronchogenic cyst. A sharply marginated
round nodular opacity (arrow) is visible in the right
lower lobe. This measured 0 HU in attenuation. This
appearance is typical of a fluid-filled bronchogenic
cyst

42. CONTRAST
ENHANCEMENT
• Cancers have a greater tendency to opacify following
contrast infusion than do some types of benign
nodules
• One currently recommended protocol uses scans at
1 minute intervals for 4 minutes following the start of
the injection of 420 mg iodine/kg (usually 75 to 125
mL) at a rate of 2 mL/sec.
• A region of interest encompassing about 60% of the
nodule diameter is used to measure enhancement

43.  Nodule enhancement of <15 HU after administration of
contrast material is strongly indicative of benignity (positive
predictive value,approximately99%).
 Rare false-negative findings are associated with central
noncavitating necrosis and adenocarcinomas (especially
bronchioloalveolar cell carcinoma), which may be related to
mucin production
 Although enhancement of more than15 HU is more likely to
represent malignancy, only 58% of nodules are malignant; the
remainder represent enhancing lesions due to active
inflammatory disease that have increased blood flow, such as
granulomas or organizing pneumonias .
Enhancing nodules should still be considered indeterminate
and require further workup.
 In summary, nodulebehavior after contrast material
administration is sensitive but not specificfor malignancy.

44. CT enhancement study in a 54-year-old woman with endometrial
hyperplasia. CT images obtained before (a) and after (b)
administration of intravenous contrast material show the
nodule has enhanced, with an increase in attenuation values of
109 HU.

45. CONTRAST
OPACIFICATION
 Some solitary (or multiple) lesions opacify following
contrast injection, thus representing vascular
structures .
Arteriovenous malformation
Pulmonary vein varix
Pulmonary artery aneurysm

46. HEMODYNAMICS
• Can be assessed by helical dynamic CT by wash in
& wash out of contrast
• Diagnostic criteria indicated a malignant nodule:
≥ 25 H wash-in and 5–31 H washout
lobulated margin
spiculated margin
absence of a satellite nodule

47. Metastatic adenocarcinoma in 57-year-old man with rectal cancer
shows net enhancement of ≥ 25H and washout of 5–31 H on
dynamic helical CT

48. GROWTH RATE
• Determination of growth rate by comparing sizes
on current and prior images is an important and
cost-effective step in the evaluation of SPNs.
• For radiographic measurement, the nodule
diameter is measured in atleast two dimensions
and averaged on two serial images.
• Doubling time (Td) is calculated with the following
equation
Td = Ti * log 2/3 * log(Di/Do),
Ti interval time, Di initial diameter & Do final
diameter.
The time for a nodule to double in volume is
referred to as the doubling time.

49. • A pulmonary nodule that doubles in volume in less
than 1 month or more than 200 days is very likely
benign.
• Slower-growing lesions often are benign tumors or
granulomas. More rapidly growing lesions usually
are inflammatory
• For most of malignancies doubling time is 30-400
days.
• 30 days for small cell carcinoma,
• 100 days for squamous cell and large cell
carcinoma,
• 180 days for adenocarcinoma.

50. • LIMITATIONS: It is difficult to reliably detect growth
in small (< 1cm) nodules
• For subsolid nodules, the limitations in assessing
growth are compounded because they are typically
small & poorly defined with growth that may be
indolent and difficult to perceive.
• In contrast to growth in solid nodules, which is
based solely on size, in subsolid nodules, growth
may manifest as an increase in size, an increase in
attenuation, development of a solid component, or
an increase in size of a solid component. In
subsolid nodules, these imaging features of growth
indicate an increased risk for malignancy

51. • It has been suggested that the use of 3d volumetric
assessment, rather than diameter, is a more
accurate and reproducible method for determining
the size and growth of solid and subsolid SPNs .
• However, there is considerable controversy
regarding the most accurate method for assessing
the growth rate of solid and subsolid nodules.
• Recently mass was proposed as a more accurate
determinant of growth of subsolid nodules. CT data
may be used to calculate mass because x-ray
attenuation values are proportional to tissue density
(ie, mass per unit volume)

52. 11 a. Coned-down CT image of the chest with coronal reformation shows a 1.2-
cm subsolid nodule (arrow) in the left upper lobe. (b) Follow-up CT image
obtained 1 year later shows the nodule (arrow), which demonstrates increased
attenuation, in addition to an increase in the overall size.
12 . (a) Contrast-enhanced CT image shows a 1.8-cm nodule with pure ground-
glass attenuation (arrow) in the left upper lobe. (b) Follow-up CT image
obtained 3 months later shows the nodule (arrow), with a new solid component
posteriorly (arrowhead). Biopsy was performed, and results of histologic
analysis revealed adenocarcinoma.

53. UNUSUAL PATTERNS OF GROWTH
• Isolated cystic airspace with increased wall
thickness should raise the suspicion of lung
cancer.
• Although most lung cancers grow at a steady
exponential rate, a temporary regression in growth
can occur which may be related to the
development of a fibrous component and
subsequent collapse of the fibrosis.
• Accordingly, a decrease in nodule size requires
continued imaging reassessment to confirm long-
term stability or resolution

54. Lung cancer manifesting with increased wall thickness of a cystic airspace
in a 77-year-old man with a history of right upper lobectomy for
adenocarcinoma. (a) Contrast-enhanced CT image shows a cystic airspace
(*) in the right lower lobe. (b) Follow-up CT image obtained 6 months later
shows a new soft-tissue component (arrows) along the wall of the cystic
airspace. Results of histologic analysis of the soft-tissue component
revealed adenocarcinoma.

55. Transient decrease in size of a lung cancer. (a) CT image obtained at the
patient’s initial presentation shows a nodule (arrow) in the left lower lobe.
(b) Follow-up CT image obtained 1 year later shows the nodule (arrow),
which decreased in size. (c) CT image obtained 2 years after the initial
presentation shows the nodule (arrow), which increased in size and
lobularity.

56. FDG-PET
• Its diagnostic ability is based on increased glucose
consumption of malignant cells.
• PET is obtained by injecting 2-(fluorine-18)-fluoro-2-
deoxy-D-glucose (FDG).
• FDG is a D-glucose analog labeled with a positron
emitter (18F) that is transported through the cell
membrane and phosphorylated using normal
glycolytic pathways.
• The degree of FDG accumulation is measured using
the standardized uptake ratio (SUR); the SUR of lung
cancers usually is more than 2.5.
• FDG-PET has a sensitivity of about 95% in detecting
malignant SPNs 1 cm or more in diameter, with a
specificity of about 80%

57. • Determination of the utility of FDG PET for evaluating
SPNs takes into consideration clinical risk factor and
imaging features to determine a management course.
• For eg: patient with a low pretest likelihood (20%) of
malignancy who is being considered for serial imaging
reassessment, negative findings at PET reduce the
likelihood of malignancy to 1%, favoring conservative
management (72). However, in a patient with a high
pretest likelihood (80%) of malignancy, negative findings
at PET only reduce the likelihood of malignancy to 14%;
thus, a more aggressive course of action may be
considered, such as obtaining tissue for biopsy or
resection

58. FDG-PET in a patient with adenocarcinoma. A. HRCT shows a small right
upper lobe nodule (arrow). B. PET (coronal plane) shows the nodule to have
a very high activity (arrow). The size of the nodule on PET exceeds its real
size. PET is poor at showing the specific location of abnormalities.

59. • False positive : inflammatory lesions.
• False-negative : carcinoid tumor ,bronchioloalveolar
carcinoma, and lesions smaller than 1 cm.
• Radionuclide single-photon emission computed
tomography (SPECT) employing depreotide (a
somatostatin analogue), thallium, or FDG also may
be used to diagnose malignancy in a large lung
nodule but is less sensitive than PET for nodules
smaller than 2 cm.

60. Infection mimicking malignancy in a 30- year-old man with no symptoms
and a right lower lobe mass detected at chest radiography performed for
a routine occupational health examination. (a, b) Unenhanced CT (a) and
PET/CT (b) images show a 3-cm solid lesion in the right lower lobe
(arrow in a) with a maximum SUV of 16.7. Biopsy results revealed
granulomatous inflammation and no malignant cells. (c) Follow-up CT
image obtained 2 months later shows regression of the lesion (arrow).
Infectious and inflammatory conditions can accumulate FDG and be
misinterprete

61. PET-negative neuroendocrine tumor in a 59-year-old woman.
Unenhanced CT (a) and PET/CT (b) images show a well-
circumscribed nodule in the middle lobe (arrow) with no FDG
uptake. Results from transthoracic needle biopsy revealed a
well-differentiated neuroendocrine tumor (carcinoid).

62. INTEGRATED PET/CT
SCAN
• Provides both morphological & metabolic features at
the same time.
PET (left) and integrated PET/CT (right) images show maximum
standardized uptake value (SUV) of 8.8 in primary nodule
(arrow) in right upper lobe.

63. BIOPSY
• Various approaches include
Fiberoptic bronchoscopy (FOB),
Transthoracic needle biopsy (TNB),
Video-assisted thoracoscopic surgery(VATS)
• Fiberoptic bronchoscopy-
Limited role
Accurate for assessing endobronchial lesions,
The yield for peripheral nodules is < 60%, and is
only 25% to 30% for an SPN smaller than 2 cm
Best when a bronchus leads directly to or is seen
within the SPN (the “positive bronchus” sign).

64. Transthoracic Needle Biopsy:
• The sensitivity of TNB in diagnosing cancer is
over 90%.
• The accuracy of TNB for diagnosing benign
disease other than active infections is limited.
• Biopsy of nodules smaller than 1 cm in diameter is
associated with an increased false-negative rate.
• Complications include
Pneumothorax,
Hemorrhage,
Air embolism

65. DYNAMIC MAGNETIC RESONANCE
IMAGING
• Perfusion differences in malignant and benign
lesions were compared.
• Dynamic MR images were acquired every 10
seconds for a total of 4 minutes-T1-weighted in-
phase two-dimensional gradient-echo MR
sequence.
• Diagnostic characteristics for differentiation were
examined by using threshold values for maximum
peak enhancement and washout.

66. • The mean relative enhancement ratio and mean
slope of enhancement for the malignant SPN group
were significantly higher than those for the benign
SPN group and significantly lower than those for
the active infection group
• Significant washout was found only in malignant
lesions.
• Sensitivity, specificity, and accuracy were 96%,
88%, and 92%, respectively, for maximum peak;
and 52%, 100%, and 75% for washout.

68. Times after bolus injection of contrast material were 9.9
seconds (left), 11.0 seconds (middle), and 18.7 seconds
(right). Lesion diameter was 25 mm;, maximum relative
enhancement ratio, 0.68; and slope of enhancement,
0.077/sec.
Adenocarcinoma

69. tuberculoma
Times after bolus injection of contrast material were 0 seconds
(left), 12.1 seconds (middle), and 23.1 seconds (right). Lesion
diameter was 11 mm; maximum relative enhancement ratio,
0.04; and slope of enhancement, 0.0036/sec.

70. DIFFUSION WEIGHTED
MRI
• The signal intensity of pulmonary nodules may be
useful for malignant and benign differentiation on
DWI when a high b factor of 1,000 s/mm2 is used
using a 5-point rank scale.
 This scale was based on the following scores:
1.nearly no signal intensity;
2. signal intensity between
3.signal intensity almost equal to that of the
thoracic spinal cord
4. higher signal intensity than that of the spinal
cord; and
5. much higher signal intensity than that of the
spinal cord.

71. • When a score of 3 was considered as a threshold,
the sensitivity, specificity, and accuracy were 88.9%,
61.1%, and 79.6% respectively.
• However, the interpretation of small metastatic
nodules,nonsolid adenocarcinoma, some
granulomas, and active inflammatory nodules
should be approached with caution.

72. a. Transverse T1-weighted image (TR/TE, 150/4.6)shows mass (arrow) in right
upper lobe.
b. Transverse diffusion-weighted (DW) echo-planar image (3,084/70) obtained
with b factor of 1,000 s/mm2 shows mass (arrow) with very high signal intensity
compared with spinal cord; it scored 5 on 5-point rank scale. Spinal cord scored 3
on 5-point
rank scale on DW images obtained with b factor of 1,000 s/mm2.

73. A. Coronal T1-weighted image (TR/TE, 119/4.6) shows mass (arrow) in right lower
lobe.
B.Transverse diffusion-weighted (DW) image(4,654/70) obtained with b factor of
1,000 s/mm2 shows mass (arrow) with slightly lower signal intensity compared with
spinal cord; it scored 2 on 5-point rank scale. Spinal cord scored 3 on 5-point rank
scale on DW images obtained with b factor of1,000 s/mm2.

74. FOLLOW UP
ALGORITHIM• When performing CT for follow up attention to
radiation dose is important
• Dose savings may be achieved with the use of
widely available tube current modulation
techniques that serve as a form of automatic
exposure control; the tube current is adjusted for
overall patient size and varies, while CT data are
acquired in the axial and longitudinal directions to
maintain homogeneous image quality.
• Higher tube current is delivered to thicker and
denser areas of the body, and lower tube current is
delivered to the remaining areas.
• Typical reconstructions consist of 2.5 mm and
thicker sections for a nontargeted field of view. The
use of thin sections (1.0–1.5 mm) in the region of
interest improves z-axis spatial resolution

76. FLEISCHNER SOCIETY GUIDELINES FOR THE
EVALUATION OF
INCIDENTALLY DISCOVERED NODULES(SOLID
SPN)
NODUL
E SIZE
LOW RISK PATIENTS HIGH RISK PATIENTS
≤4 mm NO REASSESSMENT NECESSARY REASSESSMENT AT 12 MONTHS; IF STABLE,
NO FURTHER EVALUATION REQUIRED.
THE EXCEPTION IS A NONSOLID OR
PARTIALLY
SOLID NODULE, FOR WHICH REASSESSMENT
MAY BE REQUIRED TO EXCLUDE THE RISK O
INDOLENT ADENOCARCINOMA
>4 mm but
≤6 mm
REASSESSMENT CT AT 12
MONTHS; IF
STABLE, NO FURTHER
EVALUATION REQUIRED. THE
EXCEPTION IS A
NONSOLID OR PARTIALLY SOLID
NODULE, FOR WHICH
REASSESSMENT MAY BE
REQUIRED TO EXCLUDE THE RISK
OF INDOLENTADENOCARCINOMA
REASSESSMENT CT AT 6 TO 12 MONTHS
AND, IF STABLE, AGAIN AT 18 TO 24 MONTHS
>6 mm but
≤8 mm
REASSESSMENT CT AT 6 -
12MONTHS
AND, IF STABLE, AGAIN AT 18 TO
24 MONTHS
REASSESSMENT CT AT 3 TO 6 MONTHS
AND, IF STABLE, AGAIN AT 9 TO 12 MONTHS
AND AT 24 MONTHS
>8 mm: EITHER REASSESSMENT CT
SCANS AT 3, 9, AND 24 MONTHS TO
EITHER REASSESSMENT CT SCANS AT 3, 9,
AND 24 MONTHS TO ASSESS FOR STABILITY

78. Source/Reference
Factors Taken Into Consideration to
Determine the Probability of
Malignancy
www.chestx-ray.com 1. Age
2. Smoking (ever vs never and pack-
y)
3. Hemoptysis
4. History of prior malignancy
5. Nodule diameter
6. Location
7. Edge characteristics
8. Growth rate
9. Cavity wall thickness
10. Calcifi cation
11. Contrast enhancement on CT
scan .15 HU
12. PET scan
Swensen et al 26 1. Age
2. Smoking history (ever vs never)
3. History of previous malignancy . 5
y ago
4. Presence of spiculation
5. Upper lobe location
Gould et al 27 1. Age

80. BAYESIAN
ANALYSIS• Analysis of patient characteristics & selected
radiological features.
• LR = NUMBER OF MALIGNANT NODULES
NUMBER OFBENIGN NODULES
• LRs less than 1.0 typically indicate benign
lesions, whereas LRs greater than 1.0 typically
indicate malignancy.
• Odds of malignancy=sum of LR of radiological
features or patient characteristics
• Probability of malignancy (pCa) = Odds ca
1 +Odds ca

81. DECISION
ANALYSIS
• Based on pCa
pCa
<0.05 – observation
>0.05<0.6 - biopsy
>_0.6 - surgery

82. THANK
YOU