Diagnostic Imaging of Pulmonary infections

Mohamed Zaitoun
Assistant Lecturer-Diagnostic Radiology
Department , Zagazig University Hospitals
Egypt
FINR (Fellowship of Interventional
Neuroradiology)-Switzerland
zaitoun82@gmail.com

Knowing as much as
possible about your enemy
precedes successful battle
and learning about the
disease process precedes
successful management

Pulmonary Infections
1-Lobar Pneumonia
2-Round Pneumonia
3-Bronchopneumonia
4-Atypical Pneumonia
5-T.B.
6-Abscess
7-Fungal Infections : Aspergillosis
8-Parasitic Infection : Hydatid Cyst
9-Infections in the Immunocompromised

1-Lobar Pneumonia :
a) Definition
b) Etiology
c) Pathology
d) Clinical Picture
e) Radiographic Features
f) Complications of Pneumonia

a) Definition :
-A radiological pattern associated with
homogenous fibrinosuppurative
consolidation of one or more lobes of a
lung in response to a bacterial pneumonia
-Also known as a non-segmental
pneumonia or focal non-segmental
pneumonia

b) Etiology :
-The most common cause of lobar
pneumonia is Streptococcus pneumoniae
-Other causative organisms that may cause
a lobar pattern include :
1-Klebsiella Pneumoniae
2-Legionella Pneumophila
3-Haemophilus Influenzae
4-Mycobacterium Tuberculosis

c) Pathology :
-Consolidation in lobar pneumonia mainly affect
the alveolar air spaces , there is characteristic
relative sparing of the bronchi creating the
appearance of air bronchograms
-The lobar distribution of consolidation occurs
because of spread of infection across segmental
boundaries , this is facilitated by the pores of
Kohn and the canals of Lambert

d) Clinical Picture :
1-Productive cough
2-Dyspnea
3-High Grade Fever
4-Rigors
5-Malaise
6-Pleuritic pain and occasionally hemoptysis

e) Radiographic Features :
1-Plain Radiography :
-Homogenous opacification in a lobar pattern
-The opacification can be sharply defined at the
fissures although more commonly there is
segmental consolidation
-There may be presence of air bronchograms and
volume loss in the affected areas

**N.B. :
D.D. of acute consolidation :
1-Pneumona (by fat the most common cause of acute
consolidation)
2-Pulmonary hemorrhage
3-ARDS (noncardiogenic pulmonary edema seen in
critically ill patients and thought to be due to increased
capillary permeability)
4-Pulmonary edema (may cause consolidation , although
this is an uncommon manifestation)
D.D. of chronic consolidation :
1-BAC
2-Organizing pneumonia
3-Chronic eosinophilic pneumonia

2-CT :
-Lobar pneumonia can have has a pattern of
focal ground-glass opacity in a lobar or
segmental pattern , this is due to
incomplete filling of alveoli and
consolidation
-At other times there can be dense
opacification of the entire lobe

f) Complications of Pneumonia :
1-Pulmonary abscess
2-Empyema
3-Pneumatocele
4-Bronchopleural fistula :
-Abnormal communication between communication
between the airway & the pleural space
-It is caused by rupture of the visceral pleura
-By far the most common cause of BPF is surgery ,
however , other etiologies include lung abscess ,
empyema & trauma
-On imaging , new or increasing gas is present in a pleural
effusion
5-Empyema necessitans :
-Empyema necessitans is extension of an empyema to the
chest wall , most commonly secondary to T.B.

2-Round Pneumonia :
a) Definition
b) Etiology
c) Clinical Picture
d) Radiographic Features

a) Definition :
-Is a type of pneumonia usually only seen in
pediatric patients
-They are well defined rounded opacities that
represent regions of infected consolidation
-The mean age of patients with round pneumonia
is 5 years and 90% of patients who present with
round pneumonia are younger than twelve

b) Etiology :
-The infective agent in round pneumonia is
bacterial (Streptococcus pneumoniae)
c) Clinical Picture :
-Fever , sweats and cough

d) Radiographic Features :
-They most commonly occur in superior
segments of lower lobes and in the
majority of cases (98%) , they are solitary
-Round pneumonias are round well
circumscribed parenchymal opacities ,
they tend to have irregular margins
-Air bronchograms are often present

3-Bronchopneumonia :
a) Definition
b) Etiology
c) Clinical Picture

a) Definition :
-Is the acute inflammation of the walls of
the bronchioles
-It is a type of pneumonia characterized by
multiple foci of isolated acute
consolidation affecting one or
more pulmonary lobules

b) Etiology :
-Causative organisms include :
1-Staphylococcus Aureus
2-Klebsiella (often in debilitated patients and/or
alcoholics)
3-E.Coli
4-Pseudomonas (hospital acquired)
5-Haemophilus influenza (in children ,
immunocompromised adults)
-Common hospital acquired infection

1-Productive cough
2-Dyspnea
3-Low Grade Fever
4-Rigors
5-Malaise
6-Pleuritic pain and occasionally hemoptysis

-Bronchopneumonia is characterized by multiple
small nodular or reticunodular opacities which
tend to be patchy and confluent
-This represents areas of lung where there are
patches of inflammation seperated by normal
lung parenchyma
-The distribution is often bilateral and asymmetric
and predominantly involves the lung bases

Bronchopneumonia , confluent/merging parenchymal consolidation with
diffuse bilateral pulmonary involvement (multiple areas of
consolidation)

2-CT :
-Multiple foci of opacity can be seen in a
lobular pattern centered at centrilobular
bronchioles
-These foci of consolidation can overlap to
create a larger hetrogenous confluent
area of consolidation
-Exudates fill airways = no air
bronchograms

Bilateral extended and exclusively peribronchial dense infiltrations in
the right upper lobe and lower lobe as well as in the left lower lobe

Centrilobular nodules in a
patient with
bronchopneumonia
A: Scattered ill-defined
nodules represent
peribronchiolar
consolidation and may
contain a visible
bronchiole (arrow)
B: At the lung bases ,
consolidated lobules
surround air-filled
bronchioles in several
locations

4-Atypical Pneumonia :
a) Definition
b) Etiology
c) Clinical Picture
d) Radiographic Findings

a) Definition :
-Refers to the radiological pattern
associated with patchy inflammatory
changes, often confined to the pulmonary
interstitium most commonly associated
with atypical bacterial etiologies :
1-Mycoplasma Pneumoniae (most common)
2-Chlamydophila Pneumoniae
3-Legionella Pneumophila

b) Etiology :
1-Mycoplasma Pneumoniae :
-In pediatric populations and in young adults
2-Chlamydophila Pneumoniae :
-In pediatric populations and in young adults
3-Legionella Pneumophilia : (Legionnaires
Disease)
-Associated with immunocompromised patients
and exposure to contaminated aerosolised water
(for example , from air conditioning system)

-The presentation of atypical pneumonia is
often similar to the presentation of more
typical bacterial pneumonias

d) Radiographic Findings :
-Because the inflammation is often limited to
the pulmonary interstitium and the
interlobular septa , atypical pneumonia
has the radiographic features of patchy
reticular opacities , these opacities are
especially seen in the perihilar lung

A 38 year old patient with Mycoplasma pneumonia , Chest
radiograph shows a vague ill-defined opacity in the left
lower lobe

A 40 year old patient with Chlamydia pneumonia , Chest
radiograph shows multifocal patchy consolidation in the
right upper , middle and lower lobes

A 53 year old patient with severe Legionellapneumonia , Chest
radiograph shows dense consolidation in both lower lobes

Right hemithorax air space shadowing
(Legionnaires Disease)

2-CT :
-Focal ground glass opacity in a lobular distribution
, involvement is often diffuse and bilateral
-There may also be evidence of pleural effusion
-Bronchial wall thickening
-Diffuse ground glass nodules in a centrilobular
pattern are often present although they progress
to a soft tissue density as the infection and
inflammation progresses

-In Mycoplasma pneumoniae infection ,
airspace consolidation is common , HRCT
is sensitive for nodules which are seen in
89% of patients
-In Legionella Pneumophila infection ,
residual scarring may persist after
resolution of the infection

CT in a 45 year old patient with Chlamydia
pneumonia shows a right upper lobe infiltrate

A 66 year old patient with Legionella pneumonia , CT shows dense alveolar
consolidations in both lower lobe

Atypical pneumonia with widespread ill-defined centrilobular nodules
with lobular ground glass (hazy) attenuation

5-T.B. :
a) Location
b) Radiographic Features
c) Differential Diagnosis

a) Location :
-Primary infection can be anywhere in the
lung in children whereas there is a
predilection for the upper or lower zone in
adults
-Post primary infections have a strong
predilection for the upper zones
-Miliary tuberculosis is evenly distributed
throughout both lungs

b) Radiographic Features :
1-Primary Tuberculosis
2-Post Primary Pulmonary Tuberculosis
3-Miliary Pulmonary Tuberculosis

1-Primary Tuberculosis :
-Patchy areas or consolidation or even lobar
consolidation (lower lobe (60%) > upper lobes)
-Cavitation is uncommon in primary TB
-In most cases the infection becomes localized
and a caseating granuloma forms (tuberculoma)
which usually eventually calcifies and is then
known as a Ghon lesion

Consolidation in primary tuberculosis, frontal chest radiograph
demonstrates consolidation in the right middle lobe (straight arrow)
with right hilar adenopathy (curved arrow)

Pulmonary parenchymal changes and lymphadenopathy in primary
tuberculosis, T1+C shows a parenchymal lung cavity in the lingula (solid
white arrow) with enlarged necrotic subcarinal lymph nodes (black arrows),
there is accompanying collapse of the left lower lobe (open arrow)

Tuberculomas in primary tuberculosis, frontal radiograph of the right
lung demonstrates well-defined nodules (arrows), findings that are
consistent with tuberculomas

-The more striking finding especially in children is
that of ipsilateral hilar and contiguous
mediastinal (paratracheal) lymphadenopathy ,
usually right sided , this pattern is seen in over
90% of cases of childhood primary TB but only
10-30% of adults
-Pleural effusions are more frequent in adults
-Calcification of nodes is seen in 35% of cases ,
when a calcified node and a Ghon lesion are
present , the combination is known as a Ranke
complex

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

Mediastinal tuberculous adenopathy, CT+C shows multiple enlarged
mediastinal lymph nodes with central areas of low attenuation and
peripheral enhancement (arrows)

Pleural effusion, CT+C shows a large, right-sided pleural collection, the
enhancing parietal pleura is uniformly thickened (arrows)

2-Post Primary Pulmonary Tuberculosis :
-Post-primary TB also known as reactivation
TB or secondary TB occurs years later
frequently in the setting of a decreased
immune status
-In the majority of cases , post-primary TB
within the lungs develops in either :
a) Posterior segments of the upper lobes
b) Superior segments of the lower lobes

-Typical appearance of post primary TB is
that of patchy consolidation or poorly
defined linear & nodular opacities
-Cavitation is seen in 40% of cases
-Endobronchial spread along nearby
airways is a relatively common finding
resulting in a relatively well-defined 2-4
mm nodules or branching lesions (tree-in-
bud appearance) on CT

Cavitary postprimary tuberculosis, frontal radiograph demonstrates a
thick-walled cavity with smooth inner margins in the left upper lobe
(arrow)

Cavitary postprimary tuberculosis, (a) CT+C obtained with mediastinal
windowing demonstrates an enlarged mediastinal lymph node with a central
area of low attenuation (arrow), (b) Axial CT scan obtained with lung
windowing demonstrates ill-defined cavities (black arrows) accompanied by
endobronchial spread in the right upper lobe (white arrow)

Lobar pneumonia in Mycobacterium tuberculosis infection , there is an
extensive consolidation involving the right upper lobe with large
areas of cavitation

Postprimary tuberculosis , A nodular area of consolidation with a small area of central
cavitation is visible in the superior segment of the left lower lobe

Centrilobular nodules and rosettes in a patient with endobronchial
spread of tuberculosis , multiple small nodules occurring in clusters
(arrows) are common in patients with this disease , the nodules
being centrilobular , spare the pleural surfaces

Multiple small peribronchial nodules in the right upper lobe reflecting the
endobronchial spread of the disease

3-Miliary Pulmonary Tuberculosis :
-It represents hematogenous dissemination
of an uncontrolled tuberculous infection
-It is seen both in primary and post-primary
tuberculosis
-Miliary deposits appear as 1-3 mm
diameter nodules which are uniform in
size and uniformly distributed (no
calcification)

Miliary tuberculosis, frontal radiograph shows fine, discrete
nodular areas of increased opacity bilaterally

Miliary tuberculosis, HRCT obtained with lung windowing demonstrates
numerous fine, discrete nodules bilaterally in a random distribution

c) Differential Diagnosis :
From pulmonary calcification
a) Localized :
1-Tuberculosis
2-Histoplasmosis
3-Coccidioidmycosis
4-Blastomycosis

b) Calcification in a solitary nodule :
1-Hamartoma
2-Lung cancer (engulfing a pre-existing calcified
granuloma , eccentric calcification)
3-Solitary calcified metastasis (osteosarcoma ,
chondrosarcoma , mucinous adenocarcinoma of
the colon or breast , papillary carcinoma of the
thyroid)
4-Primary peripheral squamous cell or papillary
adenocarcinoma

c) Diffuse or multiple calcifications :
1-Infections :
-T.B. (healed miliary)
-Histoplasmosis
-Varicella
2-Chronic pulmonary venous hypertension (especially
mitral stenosis)
3-Silicosis
4-Metastases
5-Alveolar microlithiasis
6-Metastatic due to hypercalcaemia (CRF , secondary HPT
and multiple myeloma
7-Lymphoma following radiotherapy

d) Interstitial ossification :
1-Disseminated pulmonary ossification
2-Idiopathic

6-Abscess :
a) Etiology
b) Clinical Picture
c) Location
e) Differential Diagnosis

a) Etiology :
1-Primary abscess :
-Is one which develops as a result of primary
infection of the lung
-They most commonly arise from aspiration ,
necrotizing pneumonia or chronic pneumonia
e.g. pulmonary tuberculosis
-More with staphylococcus , Klebsiella
-In immunocompromised more with Candida
albicans , Legionella Pneumophilia

2-Secondary abscess :
-Is one which develops as a result of another
condition
-Examples include :
a) Bronchial obstruction : Bronchogenic carcinoma
, inhaled foreign body
b) Hematogeneous spread : bacterial
endocarditis , IVDU
c) Direct extension from adjacent infection :
mediastinum , subphrenic

b) Clinical Picture :
1-Acute (< 6 weeks) :
-Fever , cough and shortness of breath ,
peripheral abscesses may also cause
pleuritic chest pain
2-Chronic (> 6 weeks) :
-Symptoms are more indolent and include
weight loss and constitutional symptoms

c) Location :
-Superior segment of the right lower lobe is
the most common site of infection

-The classical appearance of a pulmonary
abscess is a cavity containing an air-fluid level
-Round in shape and appear similar in both frontal
and lateral projections
-3 phases :
Acute : more pus less air
Subacute : less pus & more air
Chronic : air only

2-CT :
-The wall of the abscess is typically thick and the
luminal surface irregular , enhance with contrast
-Abscesses vary in size and are generally rounded
in shape
-May contain only fluid or have an air-fluid level
-Typically there is surrounding consolidation
although with treatment the cavity will persist
longer than consolidation

e) Differential Diagnosis :
1-From other cavitating lesions
2-From Empyema

7-Fungal Infections :
-Two broad categories :
a) Endemic human mycoses (prevalent
only in certain geographic areas) :
1-Histoplasmosis
2-Coccidioidomycosis
3-Blastomycosis

b) Opportunistic mycoses (worldwide in
distribution) occur primarily in
immunocompromised patients (aspergillosis and
cryptococcosis may also occur in
immunocompetent hosts)
1-Aspergillosis
2-Candidiasis
3-Cryptococcosis
4-Mucormycosis

-Aspergillosis
a) Definition
b) Types

a) Definition :
-Is a collective term used to refer to a
number of conditions caused by infection
with a fungus of the Aspergillus species ,
usually Aspergillus Fumigatus

b) Types :
-According to immune status :
1-Hypersensitivity : ABPA
2-Normal : Aspergilloma
3-Mild Suppression : Semi-invasive
4-Severe Suppression : Invasive form

1-Allergic Bronchopulmonary
Aspergillosis (ABPA)
a) Etiology
b) Clinical Picture
c) Radiographic Features

a) Etiology :
-ABPA represents a complex hypersensitivity
reaction (type 1) to Aspergillus occurring almost
exclusively in patients with asthma and
occasionally cystic fibrosis
-The hypersensitivity initially causes
bronchospasm and bronchial wall edema (IgE
mediated) , ultimately there is bronchial wall
damage , bronchiectasis and pulmonary fibrosis

-Patients have atopic symptoms (especially
asthma) and present with recurrent chest
infection
-They may expectorate orange-coloured
mucous plug

c) Radiographic Features :
Early in the disease chest x-rays will appear
normal or only demonstrate changes of asthma
-Transient patchy areas of consolidation may be
evident representing eosinophilic pneumonia
-Eventually bronchiectasis may be evident
-Mucoid impaction in dilated bronchi can appear
mass-like or sausage shaped or branching
opacities

Right lower and right middle lobe nodular infiltrations ,
minimal involvement is also present in the left lower lobe

Glove finger shadow (arrow) and nodular opacities in the
right middle third

Glove finger sign , finger like projections from hilum from bronchial mucoid
impaction

Typical finger-in-glove appearance of mucoid impaction

2-CT :
-Fleeting pulmonary alveolar opacities (common
manifestation)
-Central upper lobe saccular bronchiectasis
(hallmark)
-Mucus plugging (finger in glove appearance) and
bronchial wall thickening (common)
-Chronic disease may progress to pulmonary
fibrosis predominantly in upper lobe (end stage)
-Cavitation , 10%

Areas of tubular (A, arrows) and cystic ( A, arrowhead) bronchiectasis
predominantly in the upper lobes and bilateral mucous plugging
(B, arrows)

Central bronchiectasis and bilateral signet ring sign

Fibrosis in the right apex and a noncalcified 2 cm solid density in the apical
posterior segment of the left lobe

Bronchiectasis and peribronchial thickening

2-Aspergilloma :
a) Definition
b) Clinical Picture
c) Location

a) Definition :
-Mass like fungus balls that are typically composed
of Aspergillus fumigatus
-Aspergillomas occur in patients with normal
immunity but structurally abnormal lungs with
pre-existing cavities such as :
1-T.B.
2-Sarcoidosis
3-Bronchiectasis
4-Other pulmonary cavities (bronchogenic cyst ,
pulmonary sequestration)

-Most aspergillomas are asymptomatic
-Occasionally due to surrounding reactive
vascular granulation tissue , hemoptysis
may be present

c) Location :
-Aspergillomas typically occur in the cavities
of post-primary pulmonary tuberculosis
Therefore they most frequently are found
in the posterior segments of the upper
lobes and the superior segments of the
lower lobes

-Rounded or ovoid soft tissue attenuating
masses located in a surrounding cavity
and outlined by a crescent of air
-Altering the position of the patient usually
demonstrates that the mass is mobile
thus confirming the diagnosis

2-CT :
-Well-formed cavity with a central soft tissue
attenuating rounded mass surrounded by
an air crescent sign or a Monod sign
-Small area of consolidation around cavity is
typical
-Adjacent pleural thickening common

3-Semi-Invasive Aspergillosis :
a) Definition

a) Definition :
-This form of aspergillosis occurs in mildly
immunocompromised patients and has a
pathophysiology similar to that of invasive
aspergillosis except that the disease
progresses more chronically over months
-Mortality : 30%
-Risk factors : Diabetes , alcoholism ,
pneumoconioses , malnutrition and COPD

-Appearance similar to that of invasive
aspergillosis
-Cavitation occurs at 6 months after
infection

Bilateral rounded areas of consolidation with associated cavitation in
both upper lobes

4-Invasive Aspergillosis :
a) Definition

a) Definition :
-High mortality (70%-90%) and occurs
mainly in severely immunocompromised
patients (bone marrow transplants &
leukemia)
-The infection starts with endobronchial
fungal proliferation and then leads to
vascular invasion with thrombosis and
infarction of lung (angioinvasive infection)

-Typical appearances are those of solitary
or multiple pulmonary nodules
-Wedge-like areas of ill-defined opacity may also
be seen most likely representing infarcts due to
invasion of proximal pulmonary vessels
-An air crescent may be visible when recovery
is beginning although it is seen earlier on CT

Bilateral pulmonary infiltrates (right > left) with ill-
defined cavities showing the crescent sign

Areas of cavitation seen within right middle lobe infiltrate

2-CT :
-Solitary or multiple pulmonary nodules
-A halo of hemorrhage may be seen around the nodule
as a result of invasion into pulmonary vessels and is
seen as an area of ground glass opacity
-Peripheral wedge-like areas of consolidation representing
hemorrhagic infarcts
-Within 2 weeks , 50% of nodules undergo cavitation which
results in the air crescent sign , the appearance of the air
crescent sign indicates the recovery phase (increased
granulocytic response)

Widespread ground glass opacities

Cavitary lesions with crescent sign within areas of
consolidation in the right lung

Multiple thick walled cavitary pulmonary nodules

Recovering Invasive Aspergillosis

8-Parasitic Infection : Hydatid Cyst
a) incidence
b) Location
c) Radiographic Features

a) Incidence :
The lung is the second most common site of
involvement with echinococcosis
granulosus in adults after the liver
b) Location :
-Predominantly in lower lobes , unilateral or
bilateral

c) Radiographic Features :
1-Uncomplicated Cysts :
-Multiple or solitary cystic lesion (most
common) , water density
-Diameter of 1-20 cm
-Round or oval mass with well-defined
borders
-Enhancement after contrast injection
-Hypodense content relative to the capsule

a) Posteroanterior and
b) lateral chest
radiography showing
well-defined rounded
opacities in the right
lung of a patient with
unruptured cystic
echinococcosis

Fluid containing giant cyst measuring 14.4 × 9.3 cm (white arrows) with
a thick-enhancing wall (1.29 cm), (red arrow)

2-Complicated Cysts :
-Meniscus sign or air crescent sign (rupture between the
layers of the cyst)
-Cumbo sign or onion peel sign (air lining between the
endocyst and pericyst has the appearance of an onion
peel)
-Water-lily sign (Rupture in a bronchus = wavy fluid level)
-Serpent sign (internal rupture of the cyst with collapse of
membranes of parasite into the cyst )
-Rupture in a pleura = hydropneumothorax
-Consolidation adjacent to the cyst (ruptured cyst)

The perivesicular air meniscus between the host adventitia and the parasitic
endocyst (the so-called "sign of detachment") (1) is clearly seen, as is a
"cyst within a cyst" or "sign of the double arch“ , Cumbo sign (2). The
irregular wavy nature of the fluid level produced by the collapsed hydatid
membranes floating on top of the residual hydatid fluid produces the
pathognomonic "floating water lily sign" or "sign of the camalote" (3)

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

Chest radiography showing a crescent sign (arrows) in a patient with ruptured
cystic hydatidosis

a) Posteroanterior and
b) lateral chest
radiography showing
a hydropneumothorax
in a patient with
ruptured cystic
hydatidosis with
discharge of contents
into the pleural space

Ruptured hydatid cyst : floated membrane within the cyst (serpent signs) and
pulmonary consolidation adjacent to the cyst

9-Infections in the Immunocompromised :
-50% of all AIDS patients have pulmonary
manifestations of infection or tumor
-A normal CXR does not exclude the diagnosis of
PCP
-CMV is common at autopsy but does not cause
significant morbidity or mortality; CMV antibody
titers are present in virtually all patients with
AIDS
-Use of chest CT in AIDS patients :
*Symptomatic patient with normal CXR; however,
patients will commonly first undergo induced
sputum or bronchoscopy or be put on empirical
treatment for PCP
*To clarify confusing CXR
*Work-up of focal opacities, adenopathy, nodules

1-Spectrum of Chest manifestations
2-PCP Infection
3-Mycobacterial Infection
4-Fungal Infections
5-Kaposi Sarcoma
6-AIDS-Related Lymphoma
7-Lymphoid Interstitial Pneumonia (LIP)

1-Spectrum of Chest manifestations :
a) Nodules
b) Large Opacity
c) Lymphadenopathy
d) Pleural effusion

a) Nodules :
1-Kaposi sarcoma (usually associated with
skin lesions)
2-Septic infarcts (rapid size increase)
3-Fungal: Cryptococcus, Aspergillus

b) Large Opacity : (consolidation & mass)
1-Hemorrhage
2-NHL
3-Pneumonia
4-Linear or interstitial opacities
5-PCP
6-Atypical mycobacteria
7-Kaposi sarcoma

c) Lymphadenopathy :
1-Mycobacterial infections
2-Kaposi sarcoma
3-Lymphoma
4-Reactive hyperplasia, rare in thorax

d) Pleural Effusion :
1-Kaposi sarcoma
2-Mycobacterial, fungal infection
3-Pyogenic empyema

2-PCP Infection : (Pneumocystits Carinii
Pneumonia)
-Interstitial pattern, 80% :
CXR: bilateral perihilar or diffuse
HRCT: ground-glass appearance predominantly in
upper lobe with cysts
-Progression to diffuse consolidation within days
-Normal CXR in the presence of pulmonary PCP
infection, 10%
-Multiple upper lobe air-filled cysts or
pneumatoceles (10%) causing : Pneumothorax
& Bronchopleural fistulas

38-year-old man with AIDS and Pneumocystis jiroveci pneumonia,
HRCT image shows patchy but extensive ground-glass opacity
throughout both lungs

58-year-old woman with Pneumocystis jiroveci pneumonia and dermatomyositis
and undergoing immunosuppressive therapy, transverse (A) and coronal (B)
high-resolution CT images show patchy ground-glass opacity with mid and
lower lung predominance

ransverse (A) and coronal (B) high-resolution CT images show
patchy ground-glass opacity and smooth interlobular septal
thickening (arrows)

HRCT shows numerous thin-walled cysts (arrows) on background of
patchy ground-glass opacity, mild focal consolidation (arrowhead) is
present in left lower lobe

37-year-old man with AIDS and Pneumocystis jiroveci pneumonia.
High-resolution CT image shows multiple cysts of varying size,
scattered nodules (arrowheads), and mild patchy ground-glass
opacity, left pneumothorax (arrow) has developed

3-Mycobacterial Infection :
-M. tuberculosis > M. avium-intracellulare (this pathogen
usually causes extrathoracic disease), CD4 cell count
usually <50 cells/mm
-Hilar and mediastinal adenopathy common, necrotic lymph
nodes (TB) have a low attenuation center and only rim
enhance with contrast, adenopathy in Kaposi sarcoma or
lymphoma enhances uniformly
-Pleural effusion
-Other findings are similar to non-AIDS TB (upper lobe
consolidations, cavitations)

4-Fungal Infections :
-Fungal infections in AIDS are uncommon (<5% of
patients)
-Cryptococcosis (most common); 90% have CNS
involvement
-Histoplasmosis: nodular or miliary pattern most
common; 35% have normal CXR
-Coccidioidomycosis: diffuse interstitial pattern,
thin-walled cavities

5-Kaposi Sarcoma :
-The most common tumors in AIDS are :
a) Kaposi sarcoma (15% of patients); incidence declining;
M:F = 50:1
b) Lymphoma (<5% of patients)
-Pulmonary manifestations of Kaposi sarcoma (almost
always preceded by cutaneous/visceral involvement) :
1-Nodules :
-1 to 3 cm
-Single or multiple
-Virtually always associated with skin lesions
2-Coarse linear opacities emanating from hilum
3-Pleural effusions (serosanguineous), 40%
4-Adenopathy
5-Lymphangitic tumor spread

Pulmonary KS in a 45-year-old man, (a) Chest radiograph shows multiple bilateral ill-
defined nodules (arrowheads indicate nodules on the right side), two indistinct
masses (arrows) are identified in the left hemithorax, (b) HRCT shows two irregular
flame-shaped nodules (white arrows) in the right apex and an ill-defined mass (black
arrows) in the left apex, the diagnosis was confirmed with fine-needle aspiration
biopsy of the left upper lobe mass

Thoracic AIDS-related KS in a 45-year-old man, (a) Chest radiograph demonstrates
multiple bilateral 3–5-mm micronodules in a peribronchovascular distribution,
(b) High-resolution lung CT scan shows innumerable bilateral, poorly defined
peribronchovascular micronodules, some of which exhibit coalescence, (c) CT scan
(soft-tissue windowing) depicts enlarged lymph nodes in the axillae and mediastinum
(thin arrows), note also the bilateral pleural fluid collections as well as some
nodularity (thick arrows), skin compromise is also identified in the left hemithorax
(arrowhead)

Disseminated AIDS-related KS in a 36-year-old man with thoracic involvement, (a) Chest
radiograph shows ill-defined nodular confluent opacities in the left upper lobe,
(b) Chest CT scan demonstrates multiple nodules around the bronchus for the
apicoposterior segment of the left upper lobe (black arrow), other small nodules are
also identified in the posterior segment of the right upper lobe (white arrows), (c) CT
scan (soft-tissue windowing) demonstrates enlarged enhancing lymph nodes (arrows)
in the left hilum and occupying the azygoesophageal recess

KS in a 40-year-old man with AIDS who presented with weight loss and fever,
abdominal CT scan shows a pleural mass (black arrow) with soft-tissue
enhancement in the left pleural space associated with bilateral pleural fluid
(white arrows), imaging-guided biopsy revealed KS

6-AIDS-Related Lymphoma :
-Non-Hodgkin's lymphoma (usually aggressive B-
cell type) > Hodgkin's lymphoma
-Poor prognosis
-Spectrum includes :
1-Solitary or multiple pulmonary masses, air
bronchogram, 25%
2-AIDS-related lymphoma is typically an
extranodal disease (CNS, GI tract, liver, bone
marrow): adenopathy not very prominent
3-Pleural effusions are common

7-Lymphoid Interstitial Pneumonia (LIP) :
-See Diffuse Lung Lesions

LIP in a 47-year-old woman, high-resolution CT image shows diffuse
ground-glass opacity (arrow) with multiple perivascular cysts
(arrowheads) and reticular abnormalities (*)

Diagnostic Imaging of Pulmonary infections

Diagnostic Imaging of Pulmonary infections

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