CT Scan of Chest

8/10/2019 CT Scan of Chest

1/23

CT Scan of Chest


2/23

CT scans of the chest are

very common examinations. performed for shortness of breath, chest pain,coughing up blood, and for the evaluation ofpossible cancer, biopsi.

These exams usually require intravenouscontrast but no oral contrast.

( Studies are performed with the feet entering thedonut or gantry first,) and scan time is

approximately 35 seconds


3/23

CT Scan of Chest

CT scan of chest ordered without contrast

CT scan done

Small child - 4mm thick, 4mm spiral sections Large child- 8mm thick, 8mm spiral sections

CT scan done starting at thoracic inlet through bony

thorax, arms over head with normal breathing.


4/23

CT scan starts with AI

and lateral scout and

film run to include:

Soft tissue windows Bone windows

Lung windows


5/23

When dictated, impression should include but not

limited to:

Type of Pectus Excavatum

Mild

Moderate

Severe Hailer index and from what imagemeasurement was taken.

Hailer index is the transverse (coronal)measurement divided by the Al (sagittal)measurement at its deepest point.Measurements ~3~2 arc considered severe.


6/23

Length of the deformity

Symmetty

Rotation/nonrotation of sternum

Cardiac impressions should Include but not limited to thepresence of the following:

Compression

Displacement

Distortion of shape

Puhnonary impressions should include but not limited to:

Compression

Presence of Atelectasis

Distortion of shape Skeletal (rib or vertebral) anomalies

Other organ involvement or skeletal defects that the pectusdeformity may have an effect on must also be noted.


7/23

Emergency CT Examinations of the Chest

Two reasons for ordering an emergent chest CT that are clearlyappropriate are:

A patient is becoming septic and pus is suspected within thethorax.

A patient is suspected of having adissect ion

of the aorta.

Two reasons for ordering an emergent chest CT that are currentlystill under investigation are:

A patient is suspected of having a pulmonary embolism. A patient is suspected of having a t ransect ion of the aorta.


8/23


9/23


10/23

Pulmonary Abscess
http://medinfo.ufl.edu/year2/bms5191/pulmon/images/08c.jpghttp://medinfo.ufl.edu/year2/bms5191/pulmon/images/08b.jpghttp://medinfo.ufl.edu/year2/bms5191/pulmon/images/08a.jpghttp://medinfo.ufl.edu/year2/bms5191/pulmon/images/08c.jpghttp://medinfo.ufl.edu/year2/bms5191/pulmon/images/08b.jpghttp://medinfo.ufl.edu/year2/bms5191/pulmon/images/08a.jpg


11/23

Stanford Type "A"or a Type "B".


12/23

If an aortic dissection is clinically suspected use the STAT chest

x-ray to exclude other causes that might mimic the signs and

symptoms of a dissection.


13/23

Chest Trauma

Pneumothorax 69% (44/64) Cardiac Contusion 9% 6/64)

Lung Contusion 67% (43/64) Scapula Fracture 8% (5/64)

Rib Fractures 66% (42/64) Sternal Fracture 5% (3/64)

Hemothorax 28% (18/64) Diaphragm Injury 5% (3/64)

Flail Chest 14% ( 9/64) Vascular Injury 2% (1/64)

T-Spine Fracture 13% ( 8/64) Bronchus Fracture 2% /64)

Clavicle Fracture 13% ( 8/64)


14/23

The role of CT controversial.

The advantages of CT

1) A negative CT scan excludes a significant number of patients whomight otherwise undergo an unnecessary and invasive procedure(mortality and morbidity risks for aortography are estimated at 1.7%-(1);

2) In the course of evaluating the patient for possible aortic dissectionwith CT, many other unsuspected findings not identified by plain

films are discovered including: pneumothorax, pneumomediastinum,pneumopericardium, thoracic spine fractures, sternal and manubrialfractures and other skeletal and lung trauma;

3) Using CT as a screening tool rather than the plain film to determinewho needs aortography has potential health care cost savings. cost


15/23

The disadvantagesof using CT to screen patients for aortic injury1) Delay in obtaining the definitive aortogram or delays in taking the

patient to surgery while pursuing the CT may adversely affectprognosis in patients with aortic tears. (With the increased speed ofHelical CT and the widespread use of abdominal CT to survey amajority of blunt trauma victims, this disadvantage is debatable)

2) Mediastinal hemorrhage is fairly common after blunt chest trauma.Most of these patients will not have an aortic injury, but a few will.These patients then undergo two contrast studies, a CT and anaortogram, both of which are likely to be negative.

3) Few, if any surgeons, will operate based on the CT findings ofaortic injury without angiographic confirmation.

4) The utility of detecting branch vessel injury with CT is not known.Injuries to the great vessels occur in 1-2% of patients


16/23

CT findings of aortic injury

mediastinal hemorrhage; aortic contour

deformity; intimal flap; thrombus protruding

into the aortic lumen; pseudoaneurym;

abrupt change in caliber of the descending

aorta compared with the ascending aorta(pseudocoarctation); and rarely contrast

extravasation.


17/23

protocol Helical scanning mode with

8 sec spiral time; single-breath hold acquisition through the arch;

5 mm slice collimation reconstructed every 3 mm;

Pitch of 1.5-2; and 150 cc of intravenous contrast administered via injector at 3cc/sec. (a

50 cc saline chaser is used to wash out the remaining intravenous contrast in the I.V.line.)

Scanning begins at the level of the diaphragm and progresses cephalad to above thearch.

Smart prep to monitor contrast enhancement and the Spiral CT scan is begun whencontrast reaches the right ventricle.

After the aorta and chest are scanned, we immediately proceed to scan the abdomenand pelvis from the diaphragm down, having pre-programmed this second helicalacquisition.

Both axial images of the aorta and parasagittal LAO reformatted images through theaortic arch are evaluated for contour deformities and the presence of mediastinalhemorrhage.

Thin section CT is mandatory since most tears occur in the region of the ligamentumarteriosum. This area must be carefully scrutinized for hemorrhage or contour deformityon axial and parasagittal reformatted images.

Generate 3D images of the aorta which may be helpful to both angiographers (whentrying to confirm aortic injuries with aortography) and to surgeons in planning operative

repair. Fortunately, both 2D and 3D images, which take additional time to generate, are not

critical for detecting acute injuries.


18/23


19/23


20/23


21/23


22/23


23/23

CT Scan of Chest

Documents

Transcript of CT Scan of Chest