HRCT is useful for evaluating nodular lung diseases and guiding biopsy of lung nodules. It uses thin slice images to detect and characterize pulmonary abnormalities. Solitary pulmonary nodules are evaluated based on size, appearance, location and other features. Small, well-defined nodules with benign patterns like calcification are likely to be benign, while large, irregular nodules with spiculation have a higher chance of being malignant. HRCT helps determine if biopsy is needed and guides the biopsy procedure.

1. HRCT EVALUATION OF NODULAR
LUNG DISEASES AND CT GUIDED
BIOPSY OF NODULAR LUNG
LESIONS
PRESENTER: DR SUSHMA B
MODERATOR: PROF(DR) B K DUARA

2. • HRCT -- Use of thin section CT images (0.625 to 2 mm slice thickness) often
with a high-spatial-frequency reconstruction algorithm to detect and
characterize disease affecting the pulmonary parenchyma and airways.
o A scan performed using high- spatial frequency algorithm to accentuate the
contrast between tissue of widely differing densities, eg.,
- air & vessels (lung)
- air & bone (temporal & paranasal sinus)
• Superior to chest radiography for detection of lung disease, points a specific
diagnosis and helps in identification of reversible and irreversible diseases.
INTRODUCTION
HRCT

3. • 1982– The term HRCT was first used by TODO et. al
• 1985 – Nakata et.al and Naidich et.al published first report on HRCT
Since then it has been an important tool in pulmonary
medicine.
• Recent development of MDCT scanner capable of volumetric high
resolution scanning has improved the investigation

4. Anatomy

5. Lung interstitium
Axial fiber system
Peribronchovascular
interstitium
Centrilobular
interstitium
Peripheral fiber
system
Subpleural
interstitium
Interlobular septa
LUNG INTERSTITIUM

6. LUNG INTERSTITIUM
 The peribronchovascular interstitum invests the bronchi and pulmonary artery in the perihilar region.
 The centrilobular interstitium are associated with small centrilobular bronchioles and arteries
 The subpleural interstitium is located beneath the visceral pleura; envelops the lung into fibrous sac and
sends connective tissue septa into lung parenchyma.
 Interlobular septa constitute the septas arising from the
subpleural interstitium.
 Intra lobular interstitium bridges the gap between the
centrilobular interstitium in the center of lobules and the
interlobular septa and subpleural interstitium in the
lobular periphery

7. SECONDARY PULMONARY LOBULE
 Smallest lung unit that is surrounded
by connective tissue septa.
 The basic anatomical and functional
unit.
 Irregular polyhedral in shape.
 Measures 1 to 2.5 cm

8. Anatomy of the Secondary Lobule and Its
Components
1. Interlobular septa and
subpleural
interstitium,
2. Centrilobular structures,
3. Lobular parenchyma
and acini.

9. Lobular core :
•The secondary lobule is supplied by
arteries and bronchioles that measures
approximately 1 mm in diameter.
•It consists of functioning lung
parenchyma namely the alveoli, alveolar
duct and vessels.
•The parenchyma is supported by
network of central and intra lobular
fibers of interstitium.

10. Interlobular septa and sub pleural interstitium
 The secondary pulmonary
lobule is marginated by septa
which extends from the pleural
surface.
 They measure 0.1 mm in
thickness.
 They are less well defined in
central lung.
Thin interlobular septa - A pulmonary
vein branch. The centrilobular artery.

11. PULMONARY ACINUS
 Portion of lung parenchyma supplied by a
single respiratory bronchiole.
 Size is 7 to 8 mm in adults
 3 to 24 acini = Sec Pul. Lobule
Primary Lobule: Single Alveolar duct
with its air spaces.
4-5 Primary Lobules  Acinus

12. NORMAL LUNG
ATTENUATION
 Normal lung attenuation : –700 to – 900 HU
 Attenuation gradient : densest at dependent region of lung as a result of regional
difference in blood and gas density due to gravity.
 Pit falls:
 Difference in attenuation of anterior and posterior lung ranges from 50 to 100
HU.
 In children, lung attenuation is greater than adults.

13. Size, Appearance, Distribution
Nodules and Nodular Opacities
13
Size
Small Nodules: <10 mm Miliary - <3 mm
Large Nodules: >10 mm Masses - >3 cms

14. Interstitial opacity:
 Well-defined, homogenous,
Soft-tissue density
Obscures the edges of vessels or adjacent structure
Air space:
Ill-defined, inhomogeneous.
Less dense than adjacent vessel – GGO
small nodule is difficult to identify
Appearance

15. RANDOM: no consistent relationship to any structures
PERILYMPHATIC: corresponds to distribution of lymphatics
CENTRILOBULAR: related to centrilobular structuresDistribution

17. Perilymphatic distribution
Nodules in relation to pulmonary
lymphatics seen at
 Peri hilar
 Peri bronchovascular interstitium,
 interlobular septa
 Sub pleural regions

18. Perilymphatic nodules: D/D
 Sarcoidosis
 Lymphangitic carcinomatosis
 Lymphocytic interstitial
pneumonia (LIP)
 Lymphoproliferative disorders
 Silicosis
 Amyloidosis

19. Centrilobular nodules
 Distributed primarily within the centre of the
secondary pulmonary lobule
 Reflect the presence of either interstitial or
airspace abnormalities.
 Dense or ground-glass opacity.
 Subpleural lung is typically spared- distinguishes
from diffuse random nodules.

20.  DD:
 Hypersensitivity pneumonitis.
 Respiratory bronchiolitis.
 Infectious airways diseases (endobronchial
spread of tuberculosis or nontuberculous
mycobacteria, bronchopneumonia)
 Uncommon in bronchioloalveolar
carcinoma, pulmonary edema, vasculitis.
20
Centrilobular nodules in
infection. In a patient with
bacterial bronchopneumonia

21. Tree-in-bud
 Centrilobular nodules further characterized by presence or absence of ‘‘tree-in-bud.’’
 Tree-in-bud -- Impaction of centrilobular bronchus with mucous, pus, or fluid, resulting in dilation
of the bronchus, with associated peribronchiolar inflammation .
 Dilated, impacted bronchi produce Y or V shaped structures
 This finding is almost always seen with pulmonary infections.

22.  Tree in Bud pattern

23. Random nodules
 Random nodules – No definable distribution
 Are usually distributed uniformly throughout the lung parenchyma
in a bilaterally symmetric distribution.
Random nodules: Miliary
tuberculosis.
Axial HRCT image shows
multiple nodules scattered uniformly
throughout the lung parenchyma.

24. Random nodules: D/D
 The random distribution is a result
of the haematogenous spread of
the infection.
 Haematogenous metastases
 Miliary tuberculosis
 Miliary fungal infection
 Disseminated viral infection
 Silicosis or coal-worker’s
pneumoconiosis
 Langerhans’ cell histiocytosis Miliary tuberculosis with small nodules.

25. SOLITARY PULMONARY NODULE

26. DEFINITION
* Discrete, well-marginated, nearly circular opacity less than or equal to 3 cm in
diameter that is completely surrounded by lung Parenchyma,does not touch the
hilum or mediastinum, and is without associated atelectasis or pleural effusion.

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

28. CLASSIFICATION ON CT
Solid-Soft tissue attenuation
Sub solid-ground glass attenuation
Soft tissue with ground glass attenuation

29. MORPHOLOGICAL EVALUATION
• Size
• Location
• EdgeAppearance
• Calcification
• Attenuation
• Air Bronchograms and Pseudocavitation
• Cavitation
• Satellite Nodules
• Feeding Vessel Sign

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

31. SIZE
• The smaller the nodule the more likely it Is benign.
SIZE INTERPRETATION
< 3mm 99.8% benign
4-7mm 99.1%benign
8-20mm 82%benign
>20mm 50%benign
>30mm 7%benign

32. LOCATION
•
•
* Attached nodule – 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 throughout lung
MALIGNANT- R>L;UL>LL
Adenocarcinomas – Peripheral
Small cell carcinomas- Central
Metastasis- Peripheral/sub pleural
Associated with fibrosis- Lower lobes

33. 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

34. Hamartoma presenting as a sharply defined, round nodule

35. Solitary metastasis from a head and neck carcinoma.

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

37. • PLEURAL TAIL SIGN-linear opacity is seen extending fromthe edge of a lung nodule to the pleural
surface.
• CT HALO SIGN-halo of GGO surrounding a nodule. Represents haemorrhage, inflammation and
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

38. a)Invasive aspergillosis, patient with leukemia
and granulocytopenia and halo represent
hemorrhage surrounding a septic infarction
Halo sign
b)bronchioloalveolar carcinoma, the halo represents the
presence of lepidic tumor growth

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

40. Reverse halo sign after radiofrequency ablation of a pulmonary metastasis in a 63 year-old man with
pancreatic cancer.

41. CALCIFICATION
• Most important characteristic feature
• Best detected on HRCT
• The presence of calcium in an SPN increases its
chances of benignity

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

43. a)Homogeneous calcification.
benign lesion,usually a tuberculoma
b)Concentric or “target” calcification.
One or more rings of calcium may be
seen. This pattern is typical of a
histoplasmoma

44. a)Dense central or “bull's-
eye”.Typical of
histoplasmoma or hamartoma
b)Multiple confluent nodular foci of
calcification (“popcorn” calcification;
arrow) Typical of hamartoma and
corresponds to calcification of
cartilage nodules

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

46. ATTENUATION
1. Ground-glass Opacity
2. Calcification or High Attenuation
3. Fat
4. Low (Water or Fluid) Attenuation

47. 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.

48. • Conglomerate mass.
• Focal pneumonia
• Infarction
• Rounded atelectasis.
• Bronchiolitis obliterans with organising pneumonia.
• Lymphoma.
• Lymphoproliferative diseases
Mycetoma (may mimic air bronchogram)
OTHER CAUSES

49. CAVITATION
• Both benign & malignant show cavitation.
• The thickness &nature of the wall of a cavity serves as an indicator of its
likelihood of benign/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.

50. • Cavitation –
• Infectious and inflammatory conditions, such as abscesses, infectious
granulomas, vasculitides and
• Pulmonary infarctions,
• Malignancies - primary and metastatic tumors, (squamous cell)
• smooth, thin walls - benign lesions,
• thick, irregular walls - malignant lesions.

51. LikelihoodRatio
Characteristic
Cavity wall thickness(mm)
37.97
0.72
0.07
a
c
16
4–16
4
The cavity contains an air-fluid level. This is
uncommon in malignancy and may represent
hemorrhage or infection.
Cavitary carcinoma

52. • 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
Crescent of air in aspergilloma
AIR CRESCENT SIGN

53. • 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
AIR-FLUID LEVEL

54. SATELLITE NODULES
• 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
Most typical of a benign process but
sometimes is seen with carcinoma
Tuberculosis

55. 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 associated with a
feeding vessel.

56. 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.
• SPN containing fat:
- HAMARTOMA
- LIPOMA
- LIPOID PNEUMONIA
- TERATOMA
- LIPOSARCOMA

57. Hamartomas containing fat. The nodules are rounded
and sharply defined

58. 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 in the right lower lobe. This
measured 0 HU in attenuation. Typical of a fluid-filled bronchogenic
cyst

59. CONTRAST ENHANCEMENT
• Cancers have a greater tendency to opacify following contrast infusion than do some types of
benign nodules.
• Nodule enhancement of <15 HU after administration of contrast material-benignity (PPV-
approx 99%).
• Enhancement >15 HU is more likely to represent malignancy (58%); rest represent
enhancing lesions due to active inflammatory disease, such as granulomas or organizing
pneumonias .
• Enhancing nodules should still be considered indeterminate and require further workup.

60. 54-year-old woman with endometrial hyperplasia
Before After(109 HU)

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

62. GROWTH RATE
• Growth rate determination by comparing sizes on current and prior images is an
important and cost-effective step in the evaluation of SPNs.
• A pulmonary nodule that doubles in volume in less than 1 month or more
than 200 days is very likely to be benign.
• Slower-growing lesions often are benign tumors or granulomas. More
rapidly growing lesions usually are inflammatory.

63. • 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.

64. 1 year laterSubsolid nodule in the
left upper lobe
Nodule with pure GG
attenuation in the left
upper lobe.
3 months later

65. 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

66. Adenocarcinoma manifesting as a cystic airspace in a 77-year-old man in the right lower lobe
6 months later

67. Sub-solid Nodule
• Contain a component with ground-glass attenuation (higher than
that of normal lung parenchyma and lower than that of soft tissue)
• May have purely ground-glass attenuation
• Partly solid or
• Mixed solid and ground-glass attenuation

68. 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

69. DIFFERENTIAL DIAGNOSIS OF SPN
* CONGENITAL CONDITIONS
• Sequestration
• Bronchogenic cyst
• Bronchial atresia

70.  INFLAMMATORY CONDITIONS
• INFECTIOUS * NON INFECTIOUS
- Round pneumonia - Sarcoidosis
- Abscess - Rheumatoid arthritis
- Granuloma(fungal,bacterial) - Amyloidosis
- Wegener’s granulomatosis

71.  NEOPLASTIC CONDITIONS
• BENIGN * MALIGNANT
- Hamartoma - Carcinoma(SCC,BAC)
- Chondroma - Lymphoma
- Fibroma - Carcinoid tumour
- Pulmonary metastasis

72.  VASCULAR CONDITIONS
• Hematoma
• Infarct
• AVM

73.  MISCELLANEOUS
• Fluid in fissure(pseudotumor)
• Pleural mass

76. DISEASE WITH DIFFUSE PULMONARY NODULES

77. SARCOIDOSIS
• Sarcoidosis is a systemic inflammatory disease that predominantly involves the
lungs but also may affect the joints, eyes, kidneys, and skin.
• The disease most commonly develops between the ages of 25 and 40 years.
• Although the exact cause of sarcoidosis is unknown, it may reflect a
disproportional immunologic reaction against a bacterial or environmental
antigen.

78. • Patients may have persistent cough or such systemic manifestations.
• The most common complication of sarcoidosis is respiratory
failure(pulmonary fibrosis).
• Cardiac involvement - myocardial infarction, arrhythmias, or even
sudden death.
CLINICAL FEATUTES

79. • On HRCT, sarcoidosis typically presents as irregular micronodules (1–5 mm)
with interstitial thickening that extends along the bronchovascular bundles from
the hilum to the periphery, predominantly in the upper lung zones.
• Bilaterally symmetric enlargement of hilar and paratracheal nodes develops in
up to 90% of patients with sarcoidosis.

80. SARCOIDOSIS

81. • In late stages,
- fibrous distortion of lung parenchyma seen.
• Other manifestations of sarcoidosis at CT include
- ground-glass opacities,
- alveolar sarcoidosis (airspace nodules and consolidation with air
bronchograms),
- cysts and cavitation (in necrotizing sarcoidal angitis) and
- bronchial wall thickening and airway stenosis.

82. SILICOSIS
• Silicosis is an irreversible occupational lung disease caused by chronic
inhalation of dust containing crystalline silica, leading to lung fibrosis and
emphysema.
• On thin-section CT, silicosis typically appears as fine nodular
opacifications (1–10 mm) that are diffusely scattered throughout both
lungs in a centrilobular and subpleural location.

83. * In mild disease,
only in the upper lobes and have a
posterior predominance.
* The nodules calcify( 3%) and chains of
subpleural nodules may produce
pseudoplaques

84. • The nodules in silicosis infrequently occur in relation to thickened
interlobular septa.
• The development of progressive massive fibrosis, indicating the presence
of complicated disease, is always associated with a background of small
nodules visible on thin-section CT.

85. MALIGNANCY
HEMATOGENOUS METASTASIS
• Pulmonary metastases occur in 20–30% of malignancies, usually the result
of hematogenous spread of tumor cells.
• Less commonly, they are secondary to lymphatic spread.
• Endobronchial spread is unusual but can occur with head and neck
malignancies as well as renal and breast carcinomas.

86. • On CT, hematogenous metastases typically appear as small discrete
nodules that have a peripheral and basal predominance (when limited in
number)but a uniform distribution when there are innumerable lesions.
• Some nodules may appear to be related to small branches of pulmonary
vessels.

87. • Lymphangitic metastases, smooth or
nodular thickening of the
peribronchovascular interstitium and
interlobular septa with preservation of
normal lung architecture at the lobular
level.
• Hilar lymphadenopathy occurs in
approximately 50% of cases.

88. LYMPHOMA
• Lymphoma most commonly presents as painless cervical or
supraclavicular lymphadenopathy.
• Manifestation of secondary lymphoma is multiple nodules, which
often have fuzzy outlines and are most numerous in the lower lobes.
• This appearance is usually associated with mediastinal and hilar
lymph node enlargement.
• Cyst like lesions may simulate central cavitation.

89. Multiple pulmonary nodules on a study obtained 10 months after cardiac
transplantation.

90. BRONCHOALVEOLAR CARCINOMA
• Multiple discrete small nodules, either
randomly distributed or primarily centrilobular
• May mimic hematogenous metastases.
• Diffuse, patchy, or multifocal areas of
consolidation that are peribronchovascular
and contain air bronchograms or air-filled
cystic spaces.

91. • Because fluid and mucus produced
by the tumor are of low attenuation,
a characteristic appearance in BAC is
the “CT angiogram sign,” in which
contrast-enhanced pulmonary vessels
appear denser than surrounding
opacified lung.
• Early adenocarcinoma may also present as small
pulmonary nodules.

92. RESPIRATORY BRONCHIOLITIS
On thin-section CT, RB–ILD typically produces faint micronodular nodules
(3–5 mm) and patchy ground-glass opacities that may be widespread but
predominantly tend to involve the upper lobes.

93. INFECTIONS
• Is most commonly caused by
endocarditis or an infected central
catheter.
• The nodules are diffusely distributed
and frequently cavitate.
• A characteristic appearance is feeding
vessels in association with the
peripheral nodules.
SEPTIC EMBOLI

94. REACTIVATION TUBERCULOSIS
• Innumerable tiny, discrete, relatively
well-defined nodules may be diffusely
distributed throughout both lungs.
• Multiple small and larger nodules also
may be a feature of atypical
(nontuberculous) mycobacterial
infection.

95. • The presence of small nodules in areas of lung distal to a dominant
consolidative focus of infection probably results from endobronchial spread.

96. FUNGAL INFECTIONS
- Round or oval nodules are well circumscribed and often calcify.
HISTOPLASMOSIS
Multiple pulmonary nodules also seen in
• Coccidioidomycosis
• Blastomycosis and
• Candidiasis.

97. BLASTOMYCOSIS WITH MULTIPLE INTERMEDIATE SIZED NODULES

98. ASPERGILLOSIS
- Fungal infection that often occurs in pre existing cavities caused by
tuberculosis, fungal disease, or sarcoidosis.
- Develops in immune-compromised patients and typically presents with cough,
fever, chills, dyspnea, and chest pain.
- A halo or ground-glass opacity surrounding focal dense parenchymal nodules is
a characteristic CT appearance of invasive pulmonary aspergillosis

99. PARASITIC INFECTIONS
PARAGONIMUS WESTERMANI
- well-circumscribed cystic masses with the predilection of the periphery of the lower lobes
SCHISTOSOMIASIS AND FILARIASIS produce miliary nodules

100. Hypersensitivity Pneumonitis
* A group of allergic lung diseases that are caused by chronic inhalation of a
variety of organic and chemical antigens that leads to an immunologic response of
the lung tissues.
* The most common forms are farmer’s lung and bird fancier’s lung.

101. • On thin-section CT, In acute stage, small, ill-defined centrilobular nodules and
bilateral airspace consolidation. In the subacute stage, there are patchy ground-
glass opacities with ill-defined centrilobular nodules.
• Characteristic mosaic perfusion generally affects the middle and lower lung.
• In the chronic stage, lung fibrosis produces honeycombing, traction
bronchiectasis, and architectural distortion. There also may be reticular
opacities randomly distributed in the peribronchial and subpleural regions.

102. Hypersensitivity pneumonitis

104. CT GUIDED BIOPSY OF NODULAR LUNG
LESIONS

105. Indications for CT-guided chest biopsy
(a) Solitary pulmonary nodule.
(b) Parenchymal infiltrates in which an infectious
organism cannot be isolated.
(c) Hilar mass following negative bronchoscopy.
(d) Undiagnosed mediastinal mass

106. CONTRAINDICATIONS

107. ABNORMAL VALUES THAT SHOULD BE
CORRECTED BEFORE THE PROCEDURE:

108. INFORMED CONSENT
• CT-guided lung biopsy is an invasive procedure with potential
complications, including death, obtaining informed consent is very
important.
• The British Thoracic Society guideline further suggests, “Operators
should audit their own practice and calculate their complication rates
to inform patients before consent is given.”

109. • A routine low-dose axial scan,
- 120 kVp, 30 mAs per slice, 0.5 to 1 second rotation time, and collimation of
5 mm.
• The window center and width are 0 and 2,800 HU, respectively, which allows
simultaneous visualization of vessels, tumor, pneumothorax, bone, muscle, and
fat.
SCAN PROTOCOLS

110. • The procedure is performed with a “move off and scan” approach to
minimize radiation exposure to the operator as compared with CT
fluoroscopy.
• If multiplanar reformation or volume-rendering images are needed for
detailed needle localization, we obtain a low-dose thin-collimation spiral scan
(120 kV, 40 mAs per slice, rotation time of 0.75 second, pitch of 0.924,
collimation of 64 × 0.625 mm)

111. BIOPSY PROCEDURE
PATIENT POSITIONING AND INSTRUCTIONS:
• The patient should be positioned prone,supine or lying on the side, based on
the previously planned access site and needle trajectory.
• When needed, arms can be raised above the head to widen the intercostal
spaces and obtain easier access.
* The procedure should be adequately explained to the patients with emphasis
on the potential stinging sensation during the pleural puncture and breath-hold
phases.

113. ACCESS SITE
* Whenever possible, the needle access site should be cephalic to the ribs to
avoid intercostal vessel and nerves puncture.
• In case of anterior parasternal access, internal mammary vessels should be
carefully avoided.
• Costal cartilage may traversed if needed but this may result in reduced needle
mobility.
The skin in the access site should be sterilised with standardised antiseptic
solution.

114. INTERNAL MAMMARY ARTERIES

115. TECHNIQUES
• The coaxial technique to obtain a core
biopsy is suggested for the following
reasons:
- It yields good stabilization in the
chest wall because of the lightness of the
coaxial needle,
- It allows multiple sampling,
improving diagnostic yield.

116. • When performing the coaxial
technique, never leave the outer
cannula inside the patient without the
inner stylet.
• To do so in a small branch of a
pulmonary vein could result in a
devastating air embolism, leading to
myocardial infarction, stroke, or even
death.

117. LOCAL ANAESTHESIA
• The distance between the skin and pleura should be measured.
• The needle tip should never advance through pleura when injecting
local anesthesia (Xylocaine 2% [lidocaine]). Otherwise,
pneumothorax might develop, making the following procedure more
difficult.

119. • The breath-hold technique stabilises the positions of the diaphragm, pleural planes, lung,
fissures and, ultimately target lesions; however, breath-hold capabilities can be extremely
different from patient to patient.
• Therefore, it can be easier to target larger tumours(>2/3cm) instructing the patient to
breath freely with shallow respiration; even though the target lesions moves slightly, its
large size may be sufficient to require few adjustments.
• In the remaining cases, the patient can be instructed to maintain an inspiratory or
expiratory apnoea to allow easier access to target lesions.
Breath-hold techniques and needle manipulation

121. • The most commonly used core biopsy needle is the Tru-Cut, which
consists of an outer cutting cannula and an inner slotted stylet.
• The Temno core biopsy device is another similar commonly used
automatic core biopsy needle.
• The Biopince full core is an automated end-cutting needle that produces
a full cylindrical core specimen.
BIOPSY NEEDLES

122. Temno core biopsy needleTru-Cut biopsy needle

123. Biopince full core biopsy needle

124. DYNAMIC NEEDLE MANIPULATION
• When inserting the coaxial needle, a rapid thrust to the subpleural region for at least 1
cm should be done to avoid needle tip laceration to the pleura and
• To avoid the outer cannula slipping into the pleural space during breathing.
• It is a dynamic process from skin to the lesion;. During the whole procedure, the
patient moves, lung parenchyma moves, and pneumothorax might develop.
• Thus, only some procedures exactly follow your initial planning; most cases require
adaptation and modification during the procedure.

125. AFTER MANIPULATIONINITIALLY

126. FINAL MANIPULATION
• Final manipulation is an important technique for increasing diagnostic yield
and avoiding complications.
• If the coaxial needle is inserted to the periphery of the tumor rather than the
center, we still can get diagnostic tissue by aligning the coaxial needle to the
lesion before biopsy.
• Also, post biopsy scanning can help in localizing the biopsy direction by
visualizing the small hemorrhage caused by the shock wave of the biopsy
gun.

127. 38 year old with right lower lobe mass
• The final manipulation technique is
particularly useful in conducting
small nodule core biopsy on lesions
located near the diaphragm and
avoiding vessel injury.

128. • The number of passes needed per procedure has not been defined.
• But the decision to perform more than one puncture depends on
- Procedure difficulty,
- Risk of complications,
- Quality of the first specimen obtained and
- The pathologist’s requests.
* The presence of an on-site pathologist may reduce the number of
biopsies needed.

129. • The use of a coaxial, a larger-bore needle that is kept in place to maintain
access to the target lesion, may allow multiple tissue sampling, reducing
repeated pleural or soft tissue punctures.
• Several techniques have been proposed to seal the path of the needle
after its removal to reduce the risk of pneumothorax and haemorrhage;
• The most successful option is to create a blood patch with autologous
venous blood.
MULTIPLE SAMPLES

130. • The overall pooled diagnostic accuracy of ultrasound-guided biopsy was
88.7%(446/503),with a sensitivity of 91.5%(366/ 400) and a specificity of
around 100% for the diagnosis of malignancy.
• The overall pooled diagnostic accuracy of CT guided biopsy was 92.1%
(9567/10,383), with a sensitivity of 92.1% (7343/7975) and a specificity of
around 100% for the diagnosis of malignancy
CT VERSUS ULTRASOUND
DIAGNOSTIC ACCURACY

131. FNAB VERSUS CORE BIOPSY
• The sensitivity, specificity and accuracy of FNAB for pulmonary lesions are 82 to 99%,
86 to 100% and 64 to 97%, respectively.
• Core biopsy has been shown to have slightly higher overall sensitivity, specificity and
accuracy, with respective values of 89%,97% and 93%.
• Several recent papers advocate the use of 18- and 20-gauge cutting needles as well as
coaxial techniques to improve the diagnostic yield, reporting diagnostic accuracies of 74–
95% for the diagnosis of malignancy.
• Schneider et al. observed a statistically significantly higher number of samples sufficient
for molecular testing in core biopsy than FNAB (67% vs. 46%; P = 0.007)

132. CENTRAL VERSUS AND PERIPHERAL LESIONS
* Wang et al. compared the rates of complications and diagnostic
accuracy of CT-guided biopsy in peripheral versus paramediastinal
lesions, their paper reports diagnostic accuracy of 95.4% in
paramediastinal lesions and 94.7% in peripheral lesions, with a sensitivity
of 95.6% and 94.2% respectively

133. POST PROCEDURE CARE
AND COMPLICATIONS
• Once the biopsy is performed, a CT scan of the chest is obtained to identify any immediate post-procedural
complications.
• According to some authors, the patients should be rolled over onto the punctured side to reduce the risk of
delayed pneumothorax; this is a controversial opinion, since other authors have reported no benefits of putting
patients in the “biopsy down position”.
• Observation and monitoring of vital signs for atleast 4h
• Chest films are usually acquired after 4 h to detect possible asymptomatic PNX.
• If the clinical suspicion of a PNX arises, chest radiography must be obtained immediately.
• In low-risk patients, many interventional radiology services reasonably perform lung biopsies on an outpatient
basis, with discharge at 4 h and readmission only if symptoms develop

134. PNEUMOTHORAX
• It is the most common complication.
• Most frequently after lung biopsy but can also occur after biopsies of
mediastinal, pleural and chest wall lesions.
• Usually occurs during or immediately after the procedure and it is detected on
postprocedural control scans.
• The incidence reported to be up to 61% with an average risk of 20%.
• Risk factors for PNX can be related to patient or lesions features, but also to
the biopsy technique.

135. PNEUMOTHORAX immediately after biopsy

136. • A PNX developed during the procedure can be immediately
aspirated through the introducer needle or a separate needle
inserted into the pleural space.
• The rate of PNX increases with the patient age and severity of
underlying lung disease (e.g. emphysema or chronic obstructive
disease) as well as in smaller and deeper lesions.

137. PULMONARY HEMORRHAGE AND HEMOPTYSIS
• It is the second most common complication.
• PH may occur with or without haemoptysis and can be easily detected as a
perilesional or needle tract ground-glass opacity.
• The occurrence rates of PH are estimated to be from 4 to 27% (with an
average incidence of 11%),while haemoptysis risk is upto 5%.
• Risk factors for higher-grade PH include older age, female sex,
emphysema, pulmonary hypertension, coaxial technique, subsolid lesions,
nonsubpleural location and lesion size smaller than 3 cm

138. • Usually this complication does not need any treatment and the only
recommendation is to place the patient in a lateral position, with the biopsy side
down, to avoid aspiration of blood into the unaffected lung.
• Occasionally a larger, higher-grade PH occurs and oxygen as well as pro-
coagulative therapy may be needed

139. In patients with abnormal coagulation profile after correction, more
invasive biopsy techniques that imply the use of the core needle and
coaxial technique should be avoided as should prolonged procedures with
extended needle paths.

140. Haemothorax is an extremely rare and more severe complication, usually
due to puncture of an intercostal or less commonly a large thoracic vessel,
or mammary vessels in the case of an anterior parasternal biopsy.

141. AIR EMBOLISM
• The occurrence of systemic air embolism (SAE) in the left atrium, left
ventricle or systemic circulation is a rare (incidence 0.01% and 0.21%),
but potentially fatal (by brain or cardiac infarct) event.
• There are three mechanisms in particular responsible for SAE during
biopsy:
- Placement of the needle tip in a pulmonary vein,
- Formation of a bronchial-venous or alveolar-venous fistula and
- Opening the outer cannula of a coaxial biopsy needle to the atmosphere.

142. • Risk factors
- biopsy of cystic or cavitary lesions (i.e. vasculitic granulomas),
- coughing during the biopsy and
- positive pressure ventilation.

143. AIR EMBOLISM

144. TUMOUR SEEDING
• Tumour seeding through the needle tract represents a very rare
complication (prevalence 0.012 and 0.061%).
• The real clinical relevance is still discussed, but it is obvious that
tumour seeding along the needle tract can significantly change patient
management and life expectancy and should be strictly avoided.
• Tumour seeding is reported to be more frequently observed after
imaging-guided core needle biopsy of pleural mesothelioma

145. • Evaluation of specific morphological features of a solitary pulmonary nodule
with conventional imaging techniques can help differentiate benign from
malignant nodules .
CONCLUSION

146. • Imaging-guided chest biopsy is an interventional procedure of pivotal
importance for several clinical conditions of pneumological,oncological and
surgical interest.
• This procedure may appear very simple and linear, but radiologists approaching
it for the first time must consider several clinical and technical variables
significantly affecting the final results, in terms of both diagnostic accuracy and
patient’s safety