ct procedure of neck, avinesh shrestha

Anatomy

In general , neck is the part of a person’s or animal’s body connecting the head to the rest

of the body.

Here, neck is the part extending from the mandible to the thoracic inlet anteriorly and

from the base of the skull to the scapulae posteriorly.

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Clinically, Neck is divided into different areas which are:

Anterior Triangle

Posterior Triangle

Also all triangles mentioned here are paired i.e. they will appear on the left and the right

side of the neck.

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Anterior triangle:

The anterior triangle is situated at the front of the neck.

It is bounded:

Superiorly – Inferior border of the mandible (jawbone)

Laterally – Medial border of the sternocleidomastoid

Medially – Imaginary sagittal line down midline of body

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The muscles in this part of the neck are

divided as to where they lie in relation to

the hyoid bone, which are:

Suprahyoid Muscle:

Stylohyoid

Digastric

Mylohyoid

Geniohyoid

Infrahyoid Muscle:

Omohyoid

Sternohyoid

Sternothyroid

Thyrohyoid

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Suprahyoid muscle:

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Infrahyoid muscle:

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Anterior triangle is further divided into following parts:

Carotid triangle

Submental triangle

Submandibular triangle

Muscular triangle

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Carotid triangle:

The carotid triangle of the neck has the following

boundaries:

Superior: Posterior belly of the digastric muscle.

Lateral: Medial border of the sternocleidomastoid muscle.

Inferior: Superior belly of the omohyoid muscle.

The main contents of the carotid triangle are the common

carotid artery (which bifurcates within the carotid

triangle into the external and internal carotid arteries),

the internal jugular vein, and the hypoglossal and vagus

nerves.5/15/2017 9

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Submental triangle:

It is bounded:

Inferiorly – Hyoid bone.

Medially – Imaginary sagittal midline of the neck.

Laterally – Anterior belly of the digastric.

The submental triangle is situated underneath the chin.

Its main content is the submental lymph nodes, which

filter lymph draining from the floor of the mouth and

parts of the tongue.

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Submandibular triangle:

The submandibular triangle is located underneath the bodyof the mandible. It contains the submandibular gland(salivary), and lymph nodes. The facial artery and vein alsopass through this area.

The boundaries of the submandibular triangle are:

Superiorly: Body of the mandible.

Anteriorly: Anterior belly of the digastric muscle.

Posteriorly: Posterior belly of the digastric muscle.

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Muscular triangle:

This area actually have four boundaries. It doesn’t contain

vessels, It however contain some muscles and organs – the

infrahyoid muscles, the pharynx, the thyroid and parathyroid

glands.

The boundaries of the muscular triangle are:

Superiorly: The hyoid bone.

Medially: Imaginary midline of the neck.

Supero-laterally: Superior belly of the omohyoid muscle.

Infero-laterally: Inferior portion of the sternocleidomastoid

muscle.5/15/2017 12

Contd...

Posterior triangle:

The posterior triangle of the neck is an anatomical

area located in the lateral aspect of the neck.

Its boundaries are as follows:

Anterior: Posterior border of the SCM.

Posterior: Anterior border of the trapezius muscle.

Inferior: Middle 1/3 of the clavicle.

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Structures in posterior triangle are vertebral muscles,

external jugular vein, subclavian vein ,cervical plexus

etc.

Posterior triangle is divided into two divisions by the

omohyoid muscle, which are:

Occipital triangle: the larger, superior part

Subclavian triangle: the inferior part

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For imaging purposes, the boundaries of the neck are

Mandible and the Mylohyoid muscles anterosuperiorly

The base of the skull posterosuperiorly

The scapulae posteroinferiorly, and

The thoracic inlet centrally in the inferior aspect.

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Contd…

Neck Spaces

Another approach to the anatomy of the neck is the so-called 'spatial approach’.

The ‘neck space’ concept is a commonly used method in radiology in organizing the neck and

establishing appropriate differential diagnosis for pathology discovered within a specific

space of the neck.

The hyoid bone is used as a landmark to divide the neck into the suprahyoid and infrahyoid.

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Suprahyoid neck

parapharyngeal space

parotid space

pharyngeal mucosal space

masticator space

buccal space

danger space

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Infrahyoid neck

anterior cervical space

posterior cervical space

visceral space

Supra and Infrahyoid neck

carotid space

retropharyngeal space

perivertebral space

Subligual space

Submandibular space

Suprahyoid Spaces:

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Supra-Infra hyoid space:

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Infrahyoid space:

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Lymph nodes

The neck has an extensive lymphatic network containing

more than one third of the body's total number of lymph

nodes.

Typically, as many as 75 lymph nodes are located on each side

of the neck

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Lymph nodes

They are classified into following groups according to its location:

Level I:Submental & Submandibular nodes

Level II: Upper Internal Jugular Vein nodes

Level III: Middle Internal Jugular Vein nodes

Level IV: Lower internal Jugular Vein nodes

Level V: Posterior Triangle nodes(Spinal accessory, Transverse cervical,

Supraclavicular)

Level VI: Anterior Triangle nodes(Paratracheal, Pretrachial, Visceral)

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Lymph nodes

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Indications

Inflammatory, nodal and tumoral diseases including lymphoma and metastases.

Thyroid diseases

Pharyngeal lesions

Salivary glands pathologies

Detection /confirmation of lesions

Follow-ups

Baseline scans

Trauma

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Contra-indications

Hypersensitivity to iodinated contrast media

Pregnancy(relative)

Renal diseases

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Patient Preparation

Clear history should be taken along with reports of previous investigations.

Pregnancy needs to be ruled out.

Radiopaque materials should be removed from FOV.

Proper information and instruction about the procedure.

NPO for 4-5 hours prior to procedure for CECT.

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Patient Preparation

Blood creatinine levels should be in its normal limit (M=0.6 to 1.5,F=0.5-1.2 mg/dl) and

Blood urea level should range between 9 to 42 mg/dl

Signed informed consent from patient or his/her close relatives.

Irritable/uncooperative and Pediatric patients should be sedated.

Neck should be in neutral position.

The patient should be instructed to avoid swallowing movements.

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Routine Neck protocol

Patient positioning

Head first, supine with arms by the sides of the trunk with hands tucked under the hips.

Head rest/support can be applied to restrict the neck movement.

Topogram position/Landmark: lateral; level of forehead

Mode of scanning: Helical with single breath-hold technique

Scan orientation

Cranio-caudal

Starting location:Base of the skull

End location :Arch of the aorta

Cranio-caudal orientation reduces artifacts at the level of the thoracic inlet caused by

the beam-hardening effects of the contrast agent.5/15/2017 39


FOV: Just fitting the ROI.

Gantry tilt

To make the plane of the scanning parallel to the hard palate or

perpendicular to the plane of larynx.

Contrast administration: Intravenous and monophasic

Volume of contrast: 80-100 ml

Rate of injection of contrast: 2-3 ml/sec

Scan delay: 30-40 sec 5/15/2017 40


Slice thickness in reconstruction

3-5 mm

Slice interval in reconstruction

1.5-2.5 mm

Reconstruction algorithm/kernel

Medium smooth for soft tissue.

Sharp for cartilage, bone and lung parenchyma in the scan range.

3D-Reconstructions

MPR

MIP5/15/2017 41

Routine Neck TUTH Protocol

Patient positioning : Head first, supine with arms by the sides of the trunk, Head rest preferred


Mode of scanning: Helical

Scan orientation

Cranio-caudal

Starting location: Base of the skull

End location :Arch of the aorta

Slice Acquisition: 0.6x128

Recon Slice Thickness: 0.75mm

Recon Interval:0.7mm5/15/2017 42

Routine neck TUTH Protocol


Gantry tilt: Nil



Scan delay:35-40 sec

Recon Algorithm: b31s medium smooth

3D recon: MPR

Window Setting: W/L: 250/50

Filming: 3mmx3mm Axial: Plane + Contrast film

Coronal and Sag MPR film 5/15/2017 43

Protocol for Larynx and Hypopharynx

Indications

Screening for inflammatory or tumoral diseases of the larynx and hypopharynx.

Preoperative baseline scan

Post-surgery or post-chemotherapy follow-ups.

Patient positioning

Head first, supine with arms by the sides of the trunk with hands tucked under the

hips.

Head rest/support can be applied to restrict the neck movement.

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Topogram position/Landmark

lateral; level of forehead

Mode of scanning

Helical with single breath-hold technique

Scan orientation

Cranio-caudal


End location : Arch of the aorta

FOV

Just fitting the ROI.5/15/2017 45


Gantry tilt: To make the plane of the scanning parallel to the hard palate or

perpendicular to the plane of larynx.

Contrast administration: Intravenous , monophasic



Scan delay: 30-40 sec

Slice thickness in reconstruction : 3-5 mm

Slice interval in reconstruction : 1.5-2.5 mm5/15/2017 46


Reconstruction algorithm/kernel

Medium smooth for soft tissue.

Sharp for cartilage, bone and lung parenchyma in the scan range.

3D-Reconstructions

MPR

MIP

Virtual endoscopy

Dynamic maneuvers

phonation (for a better visualization of the laryngeal ventricle)

modified Valsalva (for a better visualization of the pyriform sinuses and upper airway).

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CT Carotid Angiography

Indications

Suspected occlusion of the carotid arteries, their aneurisms, dissections.

Preoperatively for head /neck tumors to detect the origin of their feeding vessels for the purpose ofligation.

The goals of CTA for cervicocranial vascular evaluation can be summarized as follows:

to accurately measure stenosis of the carotid and vertebral arteries and their branches

to evaluate the circle of Willis for completeness using three-dimensional reformationsof cerebral vasculature in relation to other structures, and

to detect other vascular lesions, such as dissections or occlusions.

Patient positioning

Head first, supine with arms by the sides of the trunk with hands tucked under the hips.

Head rest/support can be applied to restrict the neck movement.5/15/2017 48



Mode of scanning: Helical with single breath-hold technique

Scan orientation :Caudo-Cranial

Starting location: Arch of the aorta

End location : 2-3 cm above the sella


Gantry tilt: Nil

Contrast administration: Intravenous , monophasic, Saline chasing(half the volume of NS

w.r.t the volume of contrast administration is given immediately after contrast

administration, which reduces contrast volume, streak artifact and gives better and

consistent enhancement)5/15/2017 49


Volume of contrast: 80-100ml


Scan delay: 10-15 sec

Slice thickness in reconstruction : 1.0-1.5 mm

Slice interval in reconstruction : 0.5-0.75 mm

Reconstruction algorithm/kernel: smooth

3D-Reconstructions

MIP

VRT (preferably after bone subtraction) 5/15/2017 50

Carotid Angio TUTH Protocol

Patient positioning : Head first, supine with arms by the sides of the trunk, Head

rest preferred

Topogram position/Landmark:lateral; level of forehead

Mode of scanning: Helical

Scan orientation: Caudo-Cranial


End location :2-3 cm above the sella

Slice Acquisition: 0.6x128

Recon Slice Thickness: 0.75mm

Recon Interval:0.7mm5/15/2017 51


Gantry tilt: Nil


Rate of injection of contrast: 4-5ml/sec

Bolus Tracking(ROI: Arch of aorta), Post Threshold Delay:5 sec

Window Setting: W/L: 800/90

Recon Algorithm: b30f medium smooth

3D recon: MIP, VRT(with subtraction) 5/15/2017 52

Carotid angio TUTH Protocol

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Spaces and pathologies

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Jugular vein thrombosis


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Sarcoma

References

CT and MRI protocol- a practical approach, Satish K Bhargava.

CT and MRI of whole body, Fifth edition, Johan R. Hagga.

Anatomy for Diagnostic Imaging, second edition

Sectional Anatomy for Imaging Professionals, ed 2, LORRIE L. KELLEY

www.radiologyassistant.nl

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ct procedure of neck, avinesh shrestha

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