Prepared By:Ala’a Ali Tayem Abed

Computed Tomography II – RAD 473

NECK CT SCAN

Soft Tissue Neck CT

Doctors frequently order a neck CT to evaluate parotid or submandibuler gland lesions or infections, head and neck diseases, various abscesses or masses, even foreign bodies that are lodged in the neck or upper airway. CT scans of the neck many times also reveal tumors or infections involving the vocal cords. Neck CT exams are often used to study a lump or mass or to look for enlarged lymph nodes or glands in the neck. Axial images from roof of orbits to the aortopulmonary window. kVp / Effective mAs / Rotation time (sec) 120 / 150 - 200 / 0.5 – 0.75 FOV : 180 mm. Thickness : 2.5 mm. Resolution : high. Contrast Volume : 120 cc, 30 sec delay (R/O mass or abscess - Routine), 15-20 sec ( for Stage lymphoma or Angiogram of carotids – Thin Slice). Soft Tissue Window: WC : 50, WW : 400 Submit images in bone and soft tissue algorithm.

Scan Coverage: Floor of sella to thoracic inlet (to scan for nodes)

Standard axial scanning at 0 degrees is depicted on the lined scout image in this patient being evaluated for possible tongue tumor. The resulting images, displayed below, all have streak artifact from the patient’s amalgams with a significant portion of the area of interest unable to be evaluated. By following this scan with butterfly images, the area obscured by the streak artifact is well seen.

NECK (BUTTERFLY IMAGING)

0 degrees

+20 degrees

-20 degrees

NECK (Nasopharynx Level)

NECK (Oropharynx Level)

NECK (Oral Cavity Level)

Pathology Case - Floor of Mouth Tumor Invading SLSs

T

T

TT

Key: T = Tumor; SLS = Sublingual SpaceME = Mandible Erosion U = Ulceration

ME

U

U

NECK (Submandibuler Level)

Normal SMGAbnormal SMG with

dilated ducts from stone

Oblique reconstruction

The submandibuler duct arises from the deep lobe of the gland (medial to mandible) and runs in the sublingual space in the floor of the mouth. The normal duct is not typically seen on CT. This patient has a dilated obstructed submandibuler duct (red arrows) from an anterior floor of the mouth tumor(T).

TT

NECK (Parotid gland)

Pathology Case

This image shows the parotid glands bilaterally. The parotid ducts runs anteriorly and curve medially at the anterior margin of the masseter muscles coursing through the buccal space. They pierce the buccinator muscles and empty into the mouth at the level of the 2ndmaxillary molar. The duct on the left is dilated(from a distal stone) which permits optimal visualization of the course of the duct. Both the gland and duct must be entirely imaged when looking for sialoliths.

Dilated parotid duct with sialocele

Normal parotid duct

Masseter muscle

Parotid glands

NECK (Infrahyoid)

CTA NECK ANGIOGRAM

Common Histories / Key Words: R/O carotid stenosis; R/O carotid or vertebral dissection/occlusion, especially associated with trauma; evaluate vessel relationships to tumors (carotid body, etc…)

Scan range: Aortic arch to roof of orbits Scan inferior to superior.Contrast: 120 cc Omnipaque 350mgI/mlBolus volume of contrast: 4cc/secondTable feed: 12mmScan time: minimum of 0.5 seconds. Scan delay: 15seconds (blind start-Not bolus tracking), or bolus tracking. IF CONTRAST NOT SEEN OR INADEQUATE, RESCAN WITH SAME PARAMETERS WITHOUT DELAY.Review increment (interval): 0.5mmReprocess axial images: to 3mm x 3mm slice thicknessSoft tissue windows(800W/200L)

Common carotid arteryInternal carotid arteryExternal carotid arterySuperior thyroid arteryFacial artery

Lingual arteryOccipital arterySuperficial temporal arteryInternal maxillary artery

External View of Skull Cutaway View of Skull

Digital subtraction cerebral angiography shows left common carotid artery stenosis (A). Immediately after stent insertion and balloon dilatation in-stent thrombus (arrow) is seen (B). Thrombus disappears after intravenous tirofiban infusion (C).

2D reconstruction of CT angiography of the neck of Patient 1 showing (A) dilatation of the right common carotid artery within the neck to its origin (short arrows) and marked dilatation of the aortic arch. The Petrous component of both internal carotid arteries can be seen to be dilated (long arrow). (B) A more posterior coronal slice showing the left common carotid artery, entire left internal carotid artery and aortic root dilatation.

Rupture of a giant carotid-ophthalmic aneurysm:(A) CT of the head shows a subarachnoid haemorrhage from a giant left carotid artery aneurysm (arrow). (B) Three-dimensional impression from the carotid-ophthalmic aneurysm; the ophthalmic artery arises from the sac (arrows). (C) Photograph from rotational run showing extravasations from contrast into the subarachnoid space.

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