Diagnostic Imaging of Focal Lung Lesions

ChestFocal Lung Lesions

Mohamed Zaitoun

Assistant Lecturer-Diagnostic Radiology Department , Zagazig University Hospitals

EgyptFINR (Fellowship of Interventional

Neuroradiology)-Switzerlandzaitoun82@gmail.com

Knowing as much as possible about your enemy precedes successful battle

and learning about the disease process precedes successful management

Focal Lung Lesions -Comment on :1-Size2-Growth3-Calcification4-Margin5-Central Lucencies6-Other Signs

1-Size : Nodule versus mass-Rounded well-defined opacity < 3 cm-If > 3 cm = mass

2-Growth : Doubling time< 1 month = inflammatory> 15 months = benign1-15 months = further evaluation

**N.B. : Follow up recommendations for noncalcified nodules in patients older than 35 years without a history of malignancy , a high risk patient is defined as a patient with a history of smoking or other risk factors for lung cancer

1-Nodule <or= 4 mm :-Low risk : No follow up-High risk : at least one follow up at 12 months , if unchanged , no further

follow up2-Nodule > 4 mm and <or= 6 mm :-Low risk : at least one follow up at 12 months , if unchanged , no further

follow up-High risk : at least 2 follow up at 6-12 months and 18-24 months if no

change3-Nodules > 6 mm and <= 8 mm :-Low risk : at least 2 follow up at 6-12 months and 18-24 months if no change-High risk : at least 3 follow up at 3-6 month , 9-12 and 24 months if no

change4-Nodule > 8 mm :-Regardless of risk , either PET , biopsy , or at least 3 follow ups at 3 , 9 & 24

months

3-Calcification :-Calcification is more in benign lesions-Mets >>> no calcium

4-Margin :-Smooth = benign lesions-Speculated (ill-defined) = malignant lesions-N.B. : Smooth well-defined margins , if no

calcifications , suspicious of metastases

5-Central Lucencies :-Fat = pulmonary hamartomaSlowly growing benign lesion , in middle age

, 50 % contains fat & 30 % contains calcium

6-Other Signs :a) Pleural tail = malignancyb) Satellite nodules surrounding a dominant

nodule = granulomatousc) Feeding & draining vessels entering the

hilar aspect of a nodule = AVMd) Halo sign (ground glass veiling around

the nodule) = lesion with angioinvasive character , aspergillosis

-Focal Lung Lesions are :a) Nodulesb) Massesc) Cavitiesd) Patches

a) Nodules : (D.D. of solitary lung nodule)1-Hamartoma2-Tuberculoma3-Carcinoid4-Bronchogenic Carcinoma5-Metastases6-Fungus7-AVM8-Haematoma9-Septic Emboli

1-Hamartoma :-Single may calcify-Smooth edge-< 3 cm

2-Tuberculoma :-The same as hamartoma-Differential Diagnosis from Hamartoma :a) Site :-Tuberculoma is more in the apex of the upper

lobe and apex of the lower lobe-Hamartoma can occur at any siteb) Multiplicity :-More in hamartoma

There is a well defined round lesion in left midzone, the lesion shows flecks of calcific foci, the two small white arrows point to the well defined borders with no evidence of malignancy

Calcified granuloma

3-Carcinoid :a) Centrally located carcinoid, 80% :-Endobronchial mass-Segmental or lobar collapse (most common

finding)-There is often marked homogeneous contrast

enhancement due to high vascularityb) Peripherally located carcinoid, 20% :-Pulmonary nodule range around 10-30mm -May enhance with contrast

CXR shows complete collapse of the left lower , CT shows a hyperattenuating nodule (126 HU) within the left main bronchus

4-Bronchogenic Carcinoma :-Speculated margins

5-Metastases :-Subpleural , 80 %-N.B. : Mets + pneumothorax in a child =

osteogenic sarcoma

Speculated margin, bronchogenic carcinoma

Metastases

Osteosarcoma metastases

6-Fungus :-Focal intracavitary mass (3-6 cm) -Upper lobes-Air surrounds the aspergilloma >> Monod

sign-Small area of consolidation around the

cavity-Adjacent pleural thickening

7-AVM :-Lower lobes-Sharply defined lobulated / rounded mass

lesion + feeding artery & draining vein-Cord like bands from the lesion to hilum

NECT

8-Hematoma :-Peripheral smooth and well-defined , 2-6

cm-Slow resolution over several weeks9-Septic Emboli :-Septic emboli usually present as multiple ill-

defined nodules-In about 50% cavitation is seen

Septic emboli

Multiple Pulmonary Nodules :1-Metastases (Most common ever)2-Septic emboli3-Wegner’s granulomatosis4-Rheumatoid Nodules5-Abscesses , commonly with staph , cavitation is

common , no calcification6-Sarcoidosis7-Caplan’s Syndrome8-AVM , multiple in 33 %

b) Masses : Solid or Cystic1-Solid :-Carcinoma or Metastases-Comment on :*Lymph nodes*Chest wall invasion (rib destruction)*Mediastinal invasion*Pleural effusion*Diaphragm*Upper abdomen (Liver , suprarenal)

-N.B. :*Multiple spiculated masses >> lymphoma

or metastases*Mets of bronchogenic >> brain &

suprarenal*Big mass in a child = neuroblastoma

2-Cystic : Hydatid cyst-Water density-Multiple cysts in the wall of a large cyst-Rupture in a bronchus = fluid level (wavy) ,

water lily sign-Meniscus sign = rupture between the layers

of the cyst-Rupture in a pleura = hydropneumothorax

Air meniscus in the superior aspect of the lesion as a result of the enlarging cyst communicating with an adjacent bronchiole

Water Lilly

c) Cavities :-Wall thickness >> thin or thick-Content >> air , air-fluid & soft tissue-Causes : ABC1-Lung Abscess2-Bulla3-Cyst (Pneumatocele & cystic bronchiectasis)4-Lung carcinoma, more in the upper lobes, squamous cell

carcinoma5-Metastases6-Wegner’s granulomatosis7-Rheumatoid Nodules8-Progressive massive fibrosis9-Sarcoidosis10-Traumatic (hematoma , traumatic lung cyst)

1-Lung Abscess :-Cavitary lesion >>*Air fluid level : acute*Air + thick wall : chronic-Air + thin wall = Abscess & Ruptured HydatidDifferential Diagnosis :Abscess : straight air fluid levelHydatid : wavy level (water Lilly)

Non-Contrast Contrast

2-Bulla :-Air filled cavity + lung shows

emphysematous changes-Peripheral-Its wall has no relation to chest wall-May be secondary infected-If ruptured >>> pneumothorax

3-Cyst : Pneumatocele :-Centered (caused by prior lung trauma or infection)-Air filled cavity , thin walled +/- air fluid level

(secondary infected)

**N.B. : Intracavitary Lesions >>-Cavity inside it a ball :1-Fungal ball2-Tumor (non-uniform wall with lymphadenopathy)3-Hydatid Cyst4-Blood Clot

**N.B. D.D. of solitary cavitary lesion :(cancer or infection)1-Primary bronchogenic carcinoma (both squamous cell &

adenocarcinoma can cavitate , squamous cell cavitates more frequently , small cell carcinoma is never known to cavitate)

2-T.B. (classically produces an upper lobe cavitation)D.D. of multiple cavitary lesions (typically vascular or

spread through the vascular system)1-Septic emboli2-Vasculitis (including Wegner granulomatosis which is

specially prone to cavitate)3-Metastases (squamous cell carcinoma and uterine

carcinosarcoma are known to cavitate)

Post infectious pneumatocele, the initial chest x-ray shows consolidation in the right lung, follow up chest done, when the patient was asymptomatic, shows multiple thin walled lucencies in the right lung

(a) Initial CXR shows a dense right upper lobe consolidation, (b) CXR a week later shows a round cyst with thin walls in the right upper lobe

Cavitating Lung Tumor

Metastases

Wegner’s granulomatosis

d) Patches :-Patches + Air bronchograms =Pneumonia or Infarction1-Pneumonia :-Pneumococcal , one patch + air bronchogram-Bronchopneumonia (staph) , more than one patch -Pneumonia >> sharp cut >> fissure :Child : Foreign bodyAdult : Carcinoma

2-Pulmonary Infarction :-Right basal , pleural + hemoptysis-Patch + air bronchogram :*Peripheral (wedge-shaped)*Pleural based patch*Pleural effusion*Filling defect in the pulmonary artery*+/- Marginal enhancement*Check pulmonary artery for a thrombus*Need clinical picture to confirm

PE causing pulmonary infarction

Pulmonary embolism causing lung infarction