DIAGNOSTIC WORKUP OF THE

THE THORACIC SURGERY

PATIENT

Akın Eraslan BALCI, MD, FETCS,

Professor of Thoracic Surgery

Euphrates University Hospital

Department of Thoracic Surgery

IMAGING OF THE THORACIC

SURGERY PATIENT

Most common used: plain chest

radiographs

Standart: erect PA, taken in full inspiration

Front of their chest against the imaging plate

X-ray beam passes from posterior to anterior

Limiting magnification of the heart and

mediastinal structures

Lateral: in regions not clearly seen on the

frontal view

CHEST RADIOGRAPHS

Unable to have a PA: portable examination at

the bedside

Imaging plate is positioned against the patient’s

back

X-ray beam passing from anterior to posterior.

The beam diverges around the heart and

mediastinum, resulting in magnification of these

structures

Creating difficulties with interpretation

Bad patients often have difficulty with breath holding

Resultant respiratory motion artifact may degrade

image quality

Lateral decubitus views

Diagnosis of a pleura effusion

Expiratory views

Diagnosis of a small pneumothorax

Advantages over film-screen systems:

Images may be electronically manipulated

İnterpretable image can be generated even if the

x-ray exposure is suboptimal

Images can be transmitted and stored

electronically, utilizing a picture archiving and

communications system (PACS)

Referring clinicians and radiologists

simultaneously both

Digital systems

Generates a cross-sectional image with a

very narrow beam of x-rays

During the scan the beam rotates around

the patient and multiple measurements are

made

The majority of CT scanners are now

multislice machines with multiple rows of

detectors (currently ranging from 4 to 256)

within the doughnut-shaped gantry.

COMPUTED TOMOGRAPHY

Most patients can hold their breath for 20

seconds, the approximate time required to

image the thorax

If very thin slices are required for improved

resolution, the scan will take longer to perform

Water = 0

Bone = +2000

Air = - 1000

Haunsfield Unit (HU)

I.V. Contrast

Suspected vascular abnormalities

Staging of carcinomas

Suspected mediastinal, hilar, pleuralabnormalities

I.V. Contrast risks:

Mild urticaria to anaphylactic shock and death

Nephotoxic potential

Severe reactions with nonionic agents: 0.4%; very severe reactions: 0.004

Iodinated Contrast

Patients with increased risk of contrast reactions Who have had a previous contrast reactions

Those with asthma

Those with multiple, well documented allergies

Existing renal impairment

With diabetes

With congestive heart failure of class III or IV

In patients with reduced effective arterial volume(nephrotic, cirrhotic)

Those receiving drugs that may impair renal function orincrease contrast nephrotocity

For contrast reactions Prohylactic use of steroids ??? and antihistamines ???

Radiation dose for CT is far greater than forconventional radiographs

CT scans constituted 7-11% of all radiologicexaminations, but contributed 47-70% of thetotal collective dose from medical x-ray examinations (UK and USA respectively)

Radiation from current CT scan use maycause as many as 1 in 50 future cases of cancer

The risk is greater in children

Direction to use USG and MRI more

Radiation Dose

SOFT TISSUE WINDOWS

At the level of the great vessels, the brachiocephalic vein is

crossing the mediastinum from left to right anterior to the

innominate, carotid, and subclavian arteries. The esophagus

can be identified posterior to the trachea (T).

At the level of the aortic arch (AA), the azygos vein can be seen lateral to the

trachea (T) as it ascends in the posterior mediastinum and arches forward to

join the superior vena cava (SVC). The right paratracheal region contains a

normal size node. The internal mammary arteries and veins are clearly seen in

the parasternal regions bilaterally.

Just below the carina, the right pulmonary artery is crossing

the mediastinum. The azygoesophageal recess can be

identified, with the lung contacting pleural overlying the

esophagus and azygos vein.

Right superior and left inferior pulmonary veins can

be seen entering the left atrium (LA).

At this level, the right ventricle (RV), right atrium (RA), left

ventricle (LV) and left atrium (LA) can be clearly identified.

LUNG WINDOWS

A, At this level, the right upper lobe bronchus can be seen along its

length as it originates from the right main stem bronchus. The major

fissures separate the upper lobes anteriorly from the lower lobes

posteriorly.

The bronchus intermedius is visible as an oval lucency. Its posterior

wall should be smooth and thin. The left main and upper lobe bronchus

can also be identified. The minor fissure is seen as a relatively

avascular region.

Image through the basal segmental bronchi of the lower

lobes showing both the bronchi and their associated vessels.

AXIAL

TWO-DIMENSIONAL MULTIPLANAR

THREE-DIMENSIONAL

ENDOLUMINAL

Determination of presence and extent of neoplastic

disease

Diagnosis of pulmonary embolism

Diagnosis of bronchiectasis, diffuse lung disease,

emphysema and small airways disease.

Guidance for interventional procedures

Localization of loculated collections of fluid if

ultrasound is not diagnostic

Evaluation of suspected mediastinal abnormalities

seen on chest x-ray examination

Indications of CT

Patient preparation is needed

High glucose levels can compete with

flourodeoxyglucose (FDG) uptake,

degraded image quality

No eat/drink for 4 hours before the scan

Diabetics require special preparation

Caffeine, nicotine, alcohol, avoided 24 h

before

Oral hydration may be helpful

POSITRON EMISSION

TOMOGRAPHY

Post biopsy 1wks

Post surgery 6 wks

Post chemotherapy 4-6 wks

Post radiation 4-6 mos

Prevent false positivity

PET negative: nodule is highly likely to be

benign (take pretest the pretest probability

of malignancy into account)

PET positive: the lesion is most likely to be

malignant

A negative PET is more accurate than a

positive PET

PET for Solitary Pulmonary

Nodules

If the lesion does prove to be malignant,

PET is the most accurate for staging

mediastinal lesions

PET/CT in a patient with a right upper lobe NSCL carcinoma with right hilar and mediastinal nodal

metastases. CT (bottom left) and PET (top right) images are fused (top left) to provide an image

with both anatomical and physiological information. Note the normal cardiac uptake and FDG

activity in the bladder.

False positive results:

Active granulomatous/inflammatory disease

False negative results:

Bronchioloalveolar carcinoma

Carcinoid

In small nodules (< 1 cm)

PET can be considered in lesions smaller

than 1cm, but negative nodules should be

closely observed.

Magnetic Resonance Imaging

The main advantages:

MRI over CT is the lack of ionizing radiation

the superior soft tissue contrast resolution

useful for imaging:

the pulmonary parenchyma

can provide excellent images of the mediastinum and chest wall.

particularly useful for imaging superior sulcustumors.

Nephrogenic systemic fibrosis (NSF), a raremultisystemic fibrosing disorder

systemic fibrosis involving skeletal muscle, bone, lungs, pleura, pericardium, myocardium, kidneys, testes and dura

The use of gadolinium-based contrast agents should be avoided in patients

with acute or chronic severe renal insufficiency (glomerular filtration rate <30mL/min/1.73m2,

acute renal insufficiency of any severity due to hepato-renal syndrome

in the perioperative liver transplantation period.

gadolinium-based MRI contrast

agents

Metallic foreign bodies in the eye

Implanted electronic devices such as

pacemakers.

Contraindications to MRI scanning

are:

most useful

the detection and characterization of pleural

disease,

particularly pleural effusions

often helpful

in guiding thoracentesis and drain placements

Ultrasound

In selected circumstances

peripheral lung lesions may be localized and biopsied using ultrasound for guidance

may be useful

in evaluating the diaphragm in cases of suspected diaphragmatic paralysis

may also be used

to assist in placement of central venous lines

Free-flowing effusion and fluid with septa. Thoracic ultrasound of a free-flowing

pleural effusion. The fluid (F) is hypoechoic (black) adjacent to the diaphragm (black

arrows). A small triangular tongue of collapsed lung is also visible (white arrow).

Thoracic ultrasound of a complex effusion containing fine

septae (arrows).

Esophageal Imaging

Barium esophograms

mucosal surface lesions and esophageal

motility

CT

does not show the mucosa in detail

demonstrates tissues surrounding the

esophagus

can evaluate extension of tumor and the

presence of lymph nodes

Endoscopic ultrasound:

the investigation of choice for the T staging of esophageal tumors

but is still not universally available.

Esophageal endoscopic ultrasound (EUS)

staging of lung cancer. In particular, lower level 7 (subcarinal), 8

(paraesophageal), and 9 (inferior pulmonary ligament) lymph nodes may be better visualized or biopsied byEUS than by endobronchial ultrasound (EBUS) ormediastinoscopy.

KEY RADIOLOGIC PRINCIPLES

THORACIC NEOPLASMS

Nodal short axis is more accurate

predictor of nodal size than long axis

Short axis >1 cm is abnormal

Paratracheal

Aortopulmonary window

Hilar

Subcarinal

Paraesophageal

General Principles

Accurate staging is critical in determining

the most appropriate therapy and

prognosis

avoid unnecessary thoracotomies

resect all patients with a resectable tumor

who are medically able to tolerate

resection

Roadmapping of the primary tumor, nodes

and metastases can be performed to aid

biopsy

Imaging principles in lung

cancer

The frontal radiograph demonstrates a large, irregularly marginated,

mass in the right upper lobe with some adjacent distortion of the

superior right hilum.

CT images confirm the presence of a thick-walled, irregularly

marginated, cavitating tumor in the right upper lobe.

Right hilar and low right paratracheal nodes are greater than 1cm in short

axis diameter (arrows). The right paratracheal nodes were positive for

malignancy at mediastinoscopy precluding surgery.

Radiographic unresectability (stage IIIB or

IV)

T4 disease:

invasion of mediastinum or diaphragm

İpsilateral pleural metastatic disease,

N3 disease

contralateral mediastinal

contralateral or ipsilateral supraclavicular nodes

M1 disease with distant metastases

The main role of CT in the assessment

of the primary tumor is in differentiation

of T3 from T4 lesions

PRIMARY TUMOR

1. Involving the trachea or narrowing the carina.

2. Tm is surrounding, distorting, or attenuating, or having greater than 180 degrees of contact with the superior vena cava, the aorta, the main pulmonary artery, right or left pulmonary artery within the mediastinal pleural reflection, or the central pulmonary veins.

3. Tm abutting SVC + elevation of the diaphragm to indicate invasion of the phrenic nerve.

4. Destruction of a vertebral body or involvement of the brachial plexus.

5. Pleural carcinomatosis on CT by soft tissue pleural nodules

CT diagnosis of T4 tumor

Computed tomography image of a large T4 tumor in the posterior

left upper lobe invading the adjacent vertebral body.

In selected cases, CT or MRI can reliably

identify involvement of major thoracic

structures (T4 disease, precluding

surgery)

Computed tomography image of an unresectable T4 tumor that is

invading the left atrium via the left inferior pulmonary vein (arrows).

Magnetic resonance imaging scan demonstrates filling defect

within the left atrium (LA) from direct tumor (T) invasion

extensive contact between the tumor and

the mediastinum

Loss of a fat plane between tumor and the

mediastinum

mass effect on adjacent mediastinal

structures

pleural and pericardial thickening

Findings for mediastinal

invasion

Doesn’t rule out surgery

unless there is invasion of the subclavian

artery or of a vertebral body

CT is limited in assessing chest wall

invasion

Chest wall invasion

The only reliable findings of chest wall

invasion are the presence of rib

destruction and a chest wall mass

However, these findings are present in only

20% to 40% of patients with surgically proven

chest wall invasion

Although the sensitivity and specificity of MRI is

greater than those of CT, MRI is also of limited

value

Computed tomography image of a large left sided tumor that is invading

the chest wall, producing an obvious chest wall mass (asterisk).

When a lung tumor abuts the parietal

pleura, the presence of chest wall pain is a

better predictor of chest wall invasion than

the appearance on the CT scan, unless

there is rib destruction.

Invasive tumors in the lung apex

characteristic clinical findings of Horner's

syndrome and pain

shoulder and arm.

CT gives:

local extent of the tumor,

Multislice CT is better.

The superior contrast resolution of MRI

makes it the preferred modality for

assessment of the extent of local tumor

invasion, particularly with respect to

brachial plexus and vascular involvement

Coronal (A)

sagittal MRI scans of the thoracic inlet show a rounded mass at the right

lung apex that is invading the chest wall at the right lung apex (asterisk).