lungs: o ww 1000 to 1500hu o wl -600 to -700hu mediastinum, hilum: o ww 350 to 500hu o wl 30 to...
TRANSCRIPT
PREPARED BY:ALA’A ALI TAYEM ABED
Computed Tomography II –
RAD 473
CHEST CT SCAN
CHEST CT IS USED TO:1. Examine abnormalities found on conventional chest x-rays.2. Help diagnose the causes of clinical signs or symptoms of disease of the chest, such as
cough, shortness of breath, chest pain, or fever.3. Detect and evaluate the extent of tumors that arise in the chest, or tumors that have
spread there from other parts of the body.4. Assess whether tumors are responding to treatment.5. Help plan radiation therapy.6. Evaluate injury to the chest, including the heart, blood vessels, lungs, ribs and spine.7. Evaluate abnormalities of the chest found on fetal ultrasound examinations.CHEST CT CAN DEMONSTRATE VARIOUS LUNG DISORDERS, SUCH AS:8. Lung cancer.9. Pneumonia.10.Tuberculosis.11.Emphysema and obstructive lung disease.12.Bronchiectasis.13.Inflammation or other diseases of the pleura, the covering of the lungs.14.Congenital abnormalities.
A CT angiogram (CTA) may be performed to evaluate the blood vessels (arteries and veins) in the chest. This involves the rapid injection of an iodine-containing fluid (contrast material) into a vein while obtaining CT images.
PATIENT PREPARATION AND CONTRASTPatient preparation:Fasting for 3-4 Hours before the examinationContrast:
• The use of contrast media which injected intravenously is important for visualization of structures within the mediastinum.
THE ADVANTAGE OF CONTRAST MEDIA :1. To Detect Lesions.2. To distinguish vessels from lesions.3. To demonstrate displacement of vessels by masses.4. To demonstrate the enhancement of pathologies.
Image Display Settings
Lungs:o WW 1000 to 1500HUo WL -600 to -700HU
Mediastinum, Hilum:o WW 350 to 500HUo WL 30 to 50HU
CHEST CT WITH OUT CONTRAST• Patient Position: Supine and arms elevated above head.• Scout (Tomogram): From lung Apices to below diaphragm, 350mm – 400mm.• Breath Hold: Inspiration.• Slice Thickness: Slice thickness : 7-10mm (3-5 mm for small lesions).• Soft tissue widow and Lung widow, Bone window if needed.
CHEST CT WITH CONTRAST• Contrast: Omni 350, 125ml.• Contrast Rate: 2.5 to 3.0 cc per sec. • Contrast delay: 50sec.
CT ANGIOGRAM CHEST • P.E., Aortic Dissection• Apex to diaphragm(avoid abdomen). • Slice Thickness: 2.5 – 3 mm. • Contrast: Omni 350, 120 - 150ml.• Contrast Rate: 4 – 5 cc per sec. • Contrast delay: : 10 – 18 seconds, or bolus tracking.
BASIC CT ANATOMY OF MAJOR ARTERIES OF MEDIASTINUM. MPA = MAIN PULMONARY ARTERY, RPA = RIGHT PULMONARY ARTERY, LPA = LEFT PULMONARY ARTERY; AA = ASCENDING AORTA; DA = DESCENDING AORTA
CT CHEST 'HIGH RESOLUTION' Indications: Lung parenchyma only, lung diseases e.g. :-1. Bronchiectasis.2. Pulmonary Fibrosis.3. Emphysema.• Representative images from Apices, hilar regions and bases. • Slice Thickness: 0.625 -1.25 mm.• Interval (Increments): 8 – 10 mm.• Lung windows only . • Contrast: None.
CT scan of chest showing the mass lesion in the anterior segment of right upper lobe with smooth lobulated margins.
Enhanced CT scan of the chest shows large, septated anterior mediastinal mass containing fat and bony elements.
Adenocarcinoma of the lung: Axial CT scan of the chest with contrast reveals a lung mass with speculated borders in the left lower lobe of the lung abutting the left major fissure.
Spiral-CT shows a huge mass occupying the entire right hemi-thorax. The mass is inhomogeneous with areas of necrosis visible. There is slight compression of the superior vena cava.
CT scan showing bronchiolitis obliterans organizing pneumonia.
(Chest CT):Pneumonia
A CT scan confirmed bilateral pneumonia associated with disseminated necrotizing lesions (arrows).
HRCT: Bronchiectasis.
Tuberculosis
Computed tomography (CT) scan showing black areas at the upper most part of the lungs representing emphysema.
HRCT (Emphysema)
HRCT ( Pulmonary Fibrosis)
Pleural Effusion
Axial CT scan in with malignant melanoma shows multiple round nodules and masses of varying sizes in both lungs, consistent with metastases. There are also small bilateral pleural effusions.
57-year-old man presenting with dyspnea and black-colored sputum diagnosed with endobronchial metastasis from melanoma. Non-enhanced CT of the chest. Axial CT images at a mid level in the chest in (a) lung window and (b) soft tissue window show a hyperdense mass (arrow) in the left main bronchus with post obstructive collapse and leftward mediastinal shift. (c) Axial CT image of a lower level in the chest demonstrates an additional hyperdense lobulated left lower lobe mass (arrow). (d) Coronal CT image shows a lytic lesion in a thoracic vertebra (arrow).
Axial CT images show three fractures involving the sixth, seventh, and ninth ribs (arrows), while the bony thorax and rib fractures are also displayed in 3D volume-rendered images.
Serial rib fractures which did not heal well (ribs 7-11 on the left side).
Enchondromas: benign medullary cartilaginous neoplasm.
Transverse cut of CT scan showing large intrathoracic bony lesion compression lung parenchyma.
Aortic AneurysmStandard axial image from a contrast-enhanced CT scan showing what appears to be an oval-shaped descending thoracic aortic aneurysm, appearing to measure as much as 8.0×5.2 cm in diameter (arrows). B, Three-dimensional reconstruction in a left anterior oblique view of same CT scan demonstrating that the descending aorta is tortuous and was consequently cut off-axis (dotted arrow) on axial CT image. The true maximal diameter of this aortic segment was only 5.6 cm (solid arrow).
The CT scan will show the true and false lumens associated with dissection. Transesophageal echocardiography (TEE) is another way of visualizing the aorta and is highly sensitive and specific for detecting dissections.
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