EVERYONE

IMAGING ANATOMY OF OESOPHAGUS

DR.Sateesh kumar

Primary D.N.BKMIO

IntroductionEmbryologyGross AnatomyBlood, Nervous

supply lymphatic drainagePhysiology of

swallowing(oesophageal phase)

Imaging ModalitiesConclusion

Introduction:The esophagus serves

as a conduit between the pharynx and the stomach .

It begins at the cricopharyngeus (c5-C6)

passes through the diaphragm to join the cardia of stomach (D10)

Length 23-37 cms correlates with individual's height and it is usually longer in men than in women.

Normal wall Thickness: adequately distended: 3mm incompletely distended:5mm A-P diameter <16mm Lateral diameter <24mm New born : length: 8-10cms starts at c4-c5 up to T9

Anatomically divided into three partsCervical(jn to notch)4-5cmsThoracic(notch to

hiatus)abdominal

Functionally divided intoupper esophageal

sphincteresophageal bodylower esophageal

sphincter

UES3 cm long zone of increased pressure at

upper end of esophagusRelaxes with swallowing – normally

remains closed (prevents swallowing of air with inspiration)

Located at the C5-C6 levelsame as criopharyngeus muscle

LES (functional sphincter)3-5 cm zone of increased pressure at lower

end of esophagusRelaxes with swallowingContracts thereafter in sequence with

transmitted pressure increases – prevents reflux

Sphincter tone provided by intrinsic myogenic activity

Sphincter relaxation due to neural activity

Esophagogastric Junction DefinitionsThe mucosal junction is marked by irregular

interdigitations, hence the term ‘Z line’. (ora serrata or Z line) – most clinically practical

Point at which tubular esophagus joins gastric pouch

Junction of esophageal circular muscle layer with oblique sling fibers of stomach (loop of Willis or collar of Helvetius)

The gastro-oesophageal junction is found constantly 40 cm distance from the incisor teeth.

Embryology:Foregut Intraembryonic

part of yolksac 10th week single

esophageal lumen with a superficial layer of ciliated epithelial cells

4th month - stratified squamous epithelium except upper n lower ends

 primitive foregut endoderm is the origin for both the future esophageal epithelium and submucosal glands.

smooth muscle ,- mesenchyme of the somites surrounding the foregut.

striated muscle-mesenchyme of the branchial arches 4, 5, and 6. vagus 5th RLN 6th.

Histology:The wall of the oesophagus comprises four layers1.The outer fibrous coat(Adventitia)2.Muscle layer with outer longitudinal and inner

circular fibers3.Sub mucosa4.Mucosa.The mucosal lining of the oesophagus is stratified

squamous epithelium throughout its length, changing to columnar epithelium only at the gastro-oesophageal junction

Unlike the remainder of the GI tract, the esophagus does not have a serosal layer, thus permitting rapid dissemination of infection and tumor

Striated muscle predominates in the upper esophagus, with smooth muscle in the lower two thirds of the esophagus.

The transition from striated to smooth muscle varies but usually occurs at the level of the aortic arch.

Course & Relations:

Cervical oesophagus:

Anteriorly: tracheaPosteriorly:

vertebral columnLaterally: carotid

sheath Thyroid

Course & RelationsAt the thoracic inlet,-

it lies slightly to the left of midline

At the mid chest - closely apposes the left mainstem bronchus and the pericardium of the left atrium

Distally lies anterior to the descending aorta to the left of midline as it enters its diaphragmatic hiatus.

Course & Relations The esophagus abuts the pleura on the right

but is relatively protected from the left pleural space by the intervening aorta.

As a result, processes involving the mid-thoracic esophagus tend to spread into the right pleural space.

On CT, there may be small collections of air in the esophageal lumen, but the presence of fluid or a luminal caliber greater than 10 mm is abnormal and suggests obstruction or a motility disorder

Oesophageal impressions: (constrictions)

Cervical : cricoidThoracic : Arch of aorta, left main

bronchus,left atrium.Abdominal: oesophageal hiatus

Anatomy – Blood SupplyCervical – inferior

thyroid arteriesThoracic – 4-6 aortic

esophageal arteries and branches of left bronchial arteries

Abdominal – left gastric artery and inferior phrenic artery

Rich interconnecting submucosal arterial plexus – runs longitudinally

Venous DrainageSubepithelial

channelsPeriesophageal

plexusCervical drainage –

inferior thyroid veinsThoracic drainage –

azygos/hemiazygos veins

Abdominal drainage – left gastric vein

Anatomy – Lymphatic Drainage

Vessels run longitudinally, then penetrate wall to enter regional nodes

Cervical – lt supraclavicular

Thoracic – tracheal, tracheobronchial, posterior mediastinal, diaphragmatic

Abdominal – celiac axis

Esophagus Innervation. A rich network of intrinsic neurons capable

of producing secondary peristalsis is found in the submucosa and between the circular and longitudinal muscle layers.

This network communicates to the central nervous system via the vagi(parasympathetic) and sympathetic Cervical: from superior and inferior

cervical sympathetic gangliaThorax: from upper thoracic and

splanchnic nervesAbdominal: from celiac ganglion

Physiology of SwallowingPrimary peristalsis – progressive, triggered

by voluntary swallowingSecondary peristalsis – progressive,

generated by distention or irritation usually from bolus not traversing through the esophagus.propels remaining bolus distally.

Tertiary peristalsis – nonprogressive (simultaneous) and uncoordinated, after voluntary or spontaneously between swallows – responsible for “corkscrew” appearance of spasm of Barium Swallow

Imaging modalities Plain radiography Contrast SwallowUSGCTMRIPET CTRadionuclide scan

Plain Radiography:

Per se plain chest xray is not modality for imaging Normal oesophagus

A chest radiograph may give clue regarding perforation ,foreign bodies, achalasia etc.

Contrast swallowContrast medium::Single contrast 1. Barium sulphate 80% suspension2. Gastrografin 3. Gastromiro (Iopamidol) non ionic water

soluble

Gastrografin should NOT be used for the investigation of a tracheo-oesophageal fistula or when aspiration is a possibility.

Barium should NOT be used if perforation is suspected.

Double contrast study: 200-250% high density , low viscocity 15-20ml . Effervescent powder(or NG Tube) is given with another mouth full of barium. Erect>prone>supine

Medications: Buscopan or glucagon for hypotonia for longer retention (not for assessment of motility disorders)

Positions: RAO ,LAO, Frontal,Lateral in erect Motility disorders(prone swallow)

Severe dysphagia?? 5ml diluted barium initially further filming n contrast based on abnormality observed

Barium has superior contrast qualities and unless there are specific contraindications, its use (rather than water-soluble agents) is preferred.

Rapid serial radiography (2 frames per s) or

video recording may be required for assessment of the laryngopharynx and upper oesophagus during deglutition

The patient is in the erect RAO position to

throw the oesophagus clear of the spine.

An ample mouthful of barium is swallowed, and spot films of the upper and lower oesophagus are taken.

.If rapid serial radiography is required, it may

be performed in the right lateral, RAO and PA positions

AP or PA ProjectionPt. supine or proneCenter midsagittal

plane to cassetteBottom of cassette

should be placed just below tip of xyphoid

Pt. drinks contrast before exposure and continues drinking during exposure

Structures Shown/Film EvaluationEntire barium filled

esophagus from lower neck to stomach

Barium should be sufficiently penetrated

Surrounding structures should be visible, not overpenetrated

No rotation on AP, PA, or lateral projections

Esophagus should be displayed between heart and spine on oblique projections

Lateral ProjectionPlace pt in lateral

positionCenter midcoronal

plane to cassetteBottom of cassette

below xyphoid process

Pt must drink continuously before and during exposure

RPO VIEW

LATERAL VIEW

Tertiary peristalisisPrimary follows

Bulbous distention of the distal esophagus is called the vestibule and corresponds to the manometrically-defined lower esophageal sphincter.

This distention is best demonstrated by breath holding in inspiration or a Valsalva maneuver.Do not mistake this for a hiatal hernia.

USG:Cervical esophagus

– can be seen posterior to Left lobe of thyroid in routine usg neck

Linear probe : 7.5-10MHz

USG:GE-JUNCTION can

be visualised in trans-abdominal sonography

Curvilinear probe: 3-5Mhz

Endoscopic USG:Evolved as the imaging

modality of choice for entire oesophagus.

Helps in visualising wall layers of oesophagus thus in perfect T-staging( superior to CT)

Helps in taking needle biopsy of suspected growth and suspicious surrounding lymphnodes.

EUSG PROBES:Standard EUS(S-

EUS) Probes combine endoscopy with usg

7.5-12 MHzRadial , linear based

on plane of scanning

E-Usg probesCatheter USG (C-

Usg probes)High resolution15-30MHzAdvantages:Technically easeShort imaging timeLack of compression

effect on small tumors

A-MINI-PROBE B.MINIPROBE WITH BALLOON SHEATHC.BLIND ESOPHAGOPROBE

Using conventional imaging frequencies, the gastrointestinal wall is displayed as 5 layers of alternating black and white echo-layers by endoscopic ultrasound

S-EUS- 5layered wall Inner(1)-outer(5) 1st layer -bright (hyper-

echoic) - superficial mucosa.

2nd (dark, hypoechoic)- deep mucosa.

3r d (hyperechoic)- submucosa and the acoustic interface between the submucosa and the muscularis propria.

4th (hypoechoic) – muscularis propria

5th layer corresponds to the adventitia

C-EUSG-9 Layered wall Layers 1-4 represent

the mucosa.1,2 – epithelium3- lamina propria,4- muscularis mucosa. 5-submucosa.6-8proper muscle

layers6- circular muscle 7- connective tissue

and interface,8-longitudinal muscle. 9- adventitia

CT-ProtocolPatient position: supine with arms elevated

above level of headTopogram position: AP 1 inch below chin to

umbilicusMode : Helical CT with single breath hold,

thus reducing breathing and cardiac artifact Scan orientation: caudocranial. starting point: Imaginary line joining both

cp angles end point: 1cm above apex of lung High-density or positive oral contrast

material swallowed directly before CT is helpful in delineating the esophageal lumen.

Scanning is performed during the portal venous phase and intravenous contrast administered at a rate of 2 to 4 mL/sec.

Slice thickness should be no more than 5 mm throughout the chest.

In patients with suspected esophageal varices, water is used as a negative contrast agent combined with intravenous contrast.

A positive oral contrast agent combined with intravenous contrast can obscure submucosal vascular structures.

Multiplanar reformatted images may also be helpful, particularly in the staging of esophageal cancer.

CT has advantage over mri in detecting lymohnodes with more accuracy

MRI The advent of fast, breath-hold MR sequences

has increased the utility of MR in evaluation of the GI tract.

But there is still role for MR imaging in evaluation of the esophagus is limited.

Cardiac gating must be incorporated, and coverage of the entire esophagus in a single breath-hold sequence remains problematic .

T1 post GAD

PET-CT: For picking metastasis and extent of spread of malignancy with in the esophagus

Nuclear medicine: Prime role for assessing oesophageal motility disorders and reflux disease especially in young children.

Endoscopy : Is now the investigation of choice for evaluating as well as obtaining biopsy at the same setting. However lack of spatial resolution and in ability to look out side the lumen are the limitations.

conclusionChest xray - no/limited role in evaluating oesophagus.Ba. Swallow is most useful modality in evaluating

oesophageal disorders Normal variants in barium swallow should not

be misinterpretedEndoscopic Usg is imaging modality of choice for T-

staging of oesophageal cancer and to check extraluminal contiguous extension

CT scan is THE imaging modality for evaluating extraluminal disease and nodal disease in carcinoma.

MRI has limited role in evaluating oesophageal disease

Radionucleotide scans are useful in motility disorders n GERD

Thank You