oesophagus ppt for ss
DESCRIPTION
For radiodiagnosisTRANSCRIPT
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