Interpretation of chest CT and X ray pdf - عملي

Mukbil Hourani M.D.

AUBMC

Diagnostic Radiology

Introduction to CXR

and

Chest CT

Objectives

• Technique

• Learn the difference

between PA vs. AP CXR

• Learn the utility of a

lateral decubitus CXR

• Anatomy

• Learn the basic anatomy of

the fissures of the lungs,

heart borders, bronchi, and

vasculature that can be

seen on a chest x-ray and

• Interpretation

• Develop a consistent

technique

• Learn the silhouette sign

Pathology

• Learn the concept of

atelectasis and the ability

to recognize it on a chest

x-ray

• Appreciate the appearance

of pulmonary edema

• Appreciate the difference

findings of atelectasis and

pneumonia

• Recognize pleural effusions

and pneumothorax

• Recognize the signs of

COPD

• Pulmonary nodules & masses

• Others….

PA View

Lateral View

Ribs and Diaphragm

Postero-anterior or Antero-posterior

Lateral Decubitus

-Assess the volume of pleural effusion and demonstrate whether a
pleural effusion is mobile or loculated.

-You could also look at the nondependent hemithorax to confirm a
pneumothorax in a patient who could not be examined erect.

Inspiration

The patient should be examined in full inspiration.

-The diaphragm should be found at about the level
of the 8th - 10th posterior rib or 5th - 6th anterior rib
on good inspiration.

Right and Left Upper Lobes

Right Middle Lobe

Right and Left Lower Lobes

Left Upper Lobe

Major Fissure

Left Lower Lobe

Right Upper Lobe

Minor or Horizontal
Fissure

Right Middle Lobe

Major Fissure

Right Lower Lobe

• Right Lung containing:

– RUL:

Apical Segment

– RUL:

Posterior Segment

– RUL:

Anterior Segment

– RML:

Lateral Segment

– RML:

Medial Segment

– RLL:

Anterior Basal Segment

• Left Lung containing:

– LUL:

Apical Posterior Segment

– LUL:

Anterior Segment

– LUL:

Lingula Superior Segment

– LUL:

Lingula Inferior Segment

– LLL:

Anteromedial Segment

CT Anatomy

Pulmonary Vasculature

Fissures

Lobes and Fissures

How to Read a Chest X-Ray

• Patient Data (name history #, age, sex, old films)

• Routine Technique: AP/PA, supine or erect

• Trachea: midline or deviated, caliber, mass

• Lungs: abnormal shadowing or lucency

• Pulmonary vessels: vascular enlargement

• Hila: masses, lymphadenopathy

• Heart: thorax: heart width > 2:1 ? Cardiac configuration?

• Mediastinal contour: width? mass? Course of aorta

• Pleura: effusion, thickening, calcification

• Bones: lesions or fractures

• Soft tissues: don’t miss a mastectomy

• ICU Films: identify tubes first and look for pneumothorax

Looking for Abnormalities

Do a directed search of the chest film

rather than simply gazing at the film

Silhouette Sign

• One of the most useful

signs in chest radiology

• Described by Dr. Ben

Felson

• The silhouette sign is in

essence elimination of

the silhouette or loss of

lung (air)/soft tissue

interface caused by a

mass or fluid in the

normally air filled lung.

• If an intrathoracic opacity

is in anatomic contact with

the heart border, then the

opacity will obscure that

border.

• The sign is commonly

applied to the heart, aorta,

chest wall, and diaphragm.

• The location of this

abnormality can help to

determine the location

anatomically.

Which lobe is it?

Silhouette Sign

For the heart, the silhouette

sign can be caused by an opacity

in the

RML, lingula, anterior

segment of the upper lobe, and

anterior portion of the pleural

cavity

This contrasts with an opacity in

the

posterior pleural cavity,

posterior mediastinum, or lower

lobes

which cause an overlap and

not an obliteration of the heart

border.

Silhouette Sign

Air Bronchogram

• Is a tubular outline of an

airway made visible by

filling of the surrounding

alveoli by fluid or

inflammatory exudates

• Six causes of air

bronchograms are;

– lung consolidation,

– pulmonary edema,

– nonobstructive pulmonary

atelectasis,

– severe interstitial disease,

– neoplasm, and

– normal expiration

Atelectasis

• Collapse or incomplete

expansion of the lung or

part of the lung

• Often caused by an

endobronchial lesion,

such as mucus plug or

tumor

• Extrinsic compression

centrally by a mass such

as lymph nodes or

peripheral compression

by pleural effusion

• Atelectasis is almost

always associated with a

linear increased density

on chest x-ray

• Indirect signs of volume

loss include vascular

crowding or fissural,

tracheal, or mediastinal

shift, towards the

collapse.

• Segmental and

subsegmental collapse

may show linear,

curvilinear, wedge

shaped opacities. This is

most often associated

with post-op patients

Atelectasis

LLL Collapse

RUL Collapse

RML Collapse

Pulmonary Edema

• Two basic types of

pulmonary edema.

– cardogenic edema

caused

by increased hydrostatic

pulmonary capillary

pressure.

– noncardogenic

pulmonary

edema, and is caused by

either altered capillary

membrane permeability

or decreased plasma

oncotic pressure.

• NOT CARDIAC

– N

ear-drowning,

– O

xygen therapy,

– T

ransfusion or trauma,

– C

NS disorder,

– A

RDS, aspiration, or

altitude sickness,

– R

enal disorder or

resuscitation,

– D

rugs,

– I

nhaled toxins,

– A

llergic alveolitis,

– C

ontrast or contusion.

Pulmonary Edema

June 2, 2009

June 4, 2009

Congestive Heart Failure

• Congestive heart failure (CHF) is one of the

most common abnormalities evaluated by

CXR.

• The earliest CXR finding of CHF is

cardiomegaly, detected as an increased

cardiothoracic ratio (>50%).

• In the pulmonary vasculature of the normal

chest, the lower zone pulmonary veins are

larger than the upper zone veins due to

gravity.

CHF

– In a patient with CHF, the

pulmonary capillary wedge

pressure rises to the 12-18

mmHg range and the upper

zone veins dilate and are

equal in size or larger,

termed

cephalization

– With increasing PCWP, (18-

24 mm. Hg.), interstitial

edema occurs with the

appearance of Kerley lines.

– Increased PCWP above this

level is alveolar edema,

often in a classic perihilar

bat wing pattern of density.

Pleural effusions also often

occur

cardiomegaly, alveolar edema, cephalization and

haziness of vascular margins.

CHF

Kerley B lines

Horizontal lines less than 2cm long, commonly found in the lower zone periphery. These

lines are the thickened, edematous interlobular septa.

Causes include; pulmonary edema, lymphangitis carcinomatosa and malignant lymphoma,

viral and mycoplasmal pneumonia, interstital pulmonary fibrosis, pneumoconiosis,

sarcoidosis, chronic CHF

Atelactasis vs. Pneumonia

Atelectasis

Pneumonia

Volume Loss

Associated Ipsilateral Shift

Linear, Wedge-Shaped

Apex at Hilum

Normal or Increased Volume

No Shift, or if Present Then

Contralateral

Consolidation, Air Space

Process

Not Centered at Hilum

Air bronchograms can occur in both.

indistinct borders, air bronchograms, and silhouetting of the

right heart border.

LLL Pneumonia

--- Pneumonia

? Pneumonia

Lung abscess

Pleural Effusion

• Upright film,

– will cause blunting on

the lateral and if

large enough, the

posterior costophrenic

sulci.

– A large effusion can

lead to a mediastinal

shift away from the

effusion and opacify

the hemithorax.

– Approximately 200 ml

of fluid are needed to

detect an effusion.

Pleural Effusion

Pericardial Effusion

• An enlarged heart shadow that

is often globular shaped

(transverse diameter is

disproportionately increased).

• Serial films can be helpful in

the diagnosis especially if rapid

changes in the size of the heart

shadow are observed.

• Approximately 400-500 ml of

fluid must be in the pericardium

to lead to a detectable change

in the size of the heart shadow

on PA CXR.

• Pericardial effusion can be

definitively diagnosed with

either echocardiography or CT

Pericardial Effusion

COPD

COPD / Emphysema

Calcified Granuloma

Tubes, Lines & Catheters

Pneumothorax

• A tension PTX; air enters

the pleural cavity and is

trapped during expiration

usually by some type of

ball valve mechanism. This

leads to increasing intra-

thoracic pressure.

Eventually the pressure

buildup is large enough to

collapse the lung and shift

the mediastinum.

Defined as air inside the

thoracic cavity but

outside the lung.

Mass vs. Infiltrate

Mass Location

;

Intraparenchymal vs. pleural vs. extrapleural

Three locations that a mass can exist in the thoracic cavity.

A = intraparenchymal
B = pleural
C = extrapleural

Mass Location

;

Intraparenchymal vs. pleural vs. extrapleural

Sub-centemetric Nodules

• Low Risk Patient

– ≤4mm

No follow-up

needed

– 4-6mm

12 mo; if no

change – stop

– 6-8mm

6-12 mo; no

change - follow-up

at 18-24 mo

– > 8mm

CT follow-up

at 3, 9, 24mo or

PET/CT, or biopsy

• High Risk Patient

– ≤ 4mm

12 mo; if no

change – stop

– 4-6mm

6-12mo; no

change - follow-up at

18-24 mo

– 6-8mm

3-6mo; no

change - follow-up at

18-24 mo

– > 8mm

CT follow-up

at 3, 9, 24mo or

PET/CT, or biopsy

Solitary Pulmonary Nodule

• A common finding on a

chest x-ray.

• Most nodules are benign

• Nodules are diagnosed

as benign if they

– Show little or no growth

for 2 years

– Calcification

• Central, laminated or

diffuse pattern indicates

a granuloma

• Eccentric calcification can

be seen in a carcinoma or

in a cancer that has

engulfed a granuloma.

Hiatal Hernia

PET/CT

CT Calcium Score & CT Coronary Angiography

Pulmonary Emboli

Aortic Aneurysm

CAD

New Developments

- This is a chest x-ray of an

adult female patient.

- The silhouette of the right

upper Mediastinum is lost

and the consolidation is

confined inferiorly by the

horizontal fissure.

- Within the consolidation air

bronchograms are evident.

- There is consolidation of the

right upper lobe

- In a patient of age 56, the presence of an

upper lobe collapse should alert one to the

possibility of an endobronchial neoplasm.

- An endobronchial malignancy may be the

underlying cause for an upper lobe collapse or

an upper lobe pneumonia which fails to resolve

with treatment.

- referral for bronchoscopy is advised

Air Bronchogram

Air bronchograms are due

to the air within bronchi

surrounded by

consolidated lung. These

smaller bronchi are not

normally delineated from

the lung, but due to

consolidation a contrast

difference occurs. They

are not always present,

but when they are they

suggest consolidation

(usually infection) in the

lung.

•

A = Right Main Stem Bronchus

B = Right Upper Lobe Bronchus

B1 = Apical Segmental Bronchus

B2 = Anterior Segmental Bronchus

B3 = Posterior Segmental Bronchus

C = Bronchus Intermedius

D = Right Middle Lobe Bronchus

D4 = Lateral Segmental Bronchus

D5 = Medial Segmental Bronchus

E = Right Lower Lobe Bronchus

E6 = Superior Segmental Bronchus

E7 = Medial Basal Segmental Bronchus

E8 = Anterior Basal Segmental Bronchus

E9 = Lateral Basal Segmental Bronchus

E10 = Posterior Basal Segmental Bronchus

F = Left Main Stem Bronchus

G = Left Upper Lobe Bronchus

G1, G2 = Apicoposterior Segmental Bronchus

G3 = Anterior Segmental Bronchus

H = Lingular Bronchus

H4 = Superior Lingular Segmental Bronchus

H5 = Inferior Lingular Segmental Bronchus

I = Left Lower Lobe Bronchus

I6 = Superior Segmental Bronchus

I7 = Medial Basal Segmental Bronchus

I8 = Anterior Basal Segmental Bronchus

I9 = Lateral Basal Segmental Bronchus

I10 = Posterior Basal Segmental Bronchus

Lobes and Fissures