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Impedance Planimetry 331
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Fig. 1 a EndoFLIPÒcontrol and display unit operated via
touch-screen. A disposable catheter is connected to a single-use
syringe containing a saline solution of known electrical
conductivity. The syringe is clamped to the central unit and
reported to be 38, 94, and 264 mm2at distension
volumes of 20, 30 and 40 ml, respectively (Kwiatek
et al. 2010a). In the esophageal body, the tubular form
of the organ is reflected by a cylindrical configuration
of the measurement bag. In most subjects, distension
reaches a plateau at a cross-sectional area of approximately 400 mm
2
(Kwiatek et al. 2011). Distensibility
of the pharyngo-esophageal sphincter has been studied
in a small group of healthy volunteers with ramp distensions up to 20 ml. At rest, a median diameter of
4.9 mm at 31 mm Hg pressure was encountered.
During dry swallows, diameter increased to 9.2 mm
(Regan et al. 2012). Fig. 2.
5 Impedance Planimetry
for Investigation of Dysphagia
In patients with swallowing disorders, impedance
planimetry is used to characterize the mechanical
properties of the esophageal wall and to localize areas
of reduced distensibility that affect bolus transport.
motor-controlled. b The EndoFLIPÒcatheter with the measurement bag filled and narrowed by two rubber bands, held in
front of the corresponding image on the screen
A clinically useful distinction between esophageal
versus oropharyngeal dysphagia is commonly made
by symptom profile. Esophageal dysphagia is characterized by the sensation of failed or incomplete
bolus transport after unimpaired deglutition, possibly
associated with retrosternal pressure or regurgitation
of non-acidified food remnants and mucus. More
severely, a bolus may be impacted in the esophagus
and require acute endoscopic intervention. Diagnostic
workup of esophageal dysphagia begins with esophago-gastroscopy and an esophagogram to exclude
tumors and to assess organ geometry and mucosal
integrity. Esophagitis, a hiatal hernia or structural
lesions such as diverticula, webs or rings may be
encountered and be responsible for the swallowing
disorder. If no structural lesion is found, symptoms
persist despite adequate treatment or if esophageal
surgery is considered, further investigation by a
motility study and reflux monitoring is indicated.
Sphincter pressures and esophageal body motility can
be assessed by manometry. Ineffective motility,
characterized by weak peristalsis, may be identified as
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Fig. 2 Distensibility of the esophago-gastric junction in a
healthy volunteer at volumes of 20-a, 30-b, 40-c and 50 ml d.
Diameter values calculated from the 16 impedance tracings are
a cause of dysphagia. This condition is frequently
associated with gastro-esophageal reflux disease and
less commonly with scleroderma or mixed connective
tissue disease. An impairment of swallow-induced
relaxation and aperistalsis of the esophageal body is a
diagnostic for achalasia. In early stages of this disease, dilatation of the tubular esophagus may not be
visible by endoscopy or video-fluoroscopy. Impedance planimetry yields clinically important information in this disease. Distensibility of the esophagogastric junction in achalasia patients is reduced
compared to healthy subjects, even if lower esophageal sphincter pressure is within the normal range
(Rohof et al. 2012). Treatment by dilatation or cardiomyotomy aims to reduce outflow obstruction at the
level of the lower esophageal sphincter. The success
listed in the column at the right side. Intrabag pressure is
displayed below the image
of treatment, measured by esophageal emptying in a
timed barium esophagram and the Eckardt dysphagia
score is significantly correlated with an increase in
esophago-gastric junction distensibility, but not
measurements of lower esophageal sphincter pressure
(Rohof et al. 2012).
A discrepancy between measures of bolus transport
and motility should be investigated by impedance planimetry. Bolus retention in the esophagus—despite
normal peristalsis—raises the suspicion of discrete
fibrotic lesions or reduced wall compliance not detectable by standard esophagram and endoscopy. Eosinophilic esophagitis, a chronic, immune/antigen-mediated
esophageal disease characterized clinically by symptoms related to esophageal dysfunction and histologically by eosinophil-predominant inflammation may be
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Fig. 3 Distensibility of the esophago-gastric junction in a
patient with eosinophilic esophagitis. There is only a minimal
increase of the smallest cross-sectional area with higher filling
the underlying cause. Diagnosis is made by a combination of clinical and histopathologic features. Symptoms
in adult patients are mainly dysphagia, food impaction
and chest pain. Multiple biopsies from the proximal and
distalesophagus should be evaluated,and a minimumof
15 eosinophil granulozytes per high power field in at
least a biopsy sample is a diagnostic criterion. Distribution of lesions may be patchy and eosinophil microabscesses are often seen. Eosinophilic esophagitis is
associated with esophagealremodelling, endoscopically
characterized by fixed or transient rings, longitudinal
furrows, diffuse esophageal narrowing and whitish
exudates(Liacouraset al. 2011). A lower complianceof
the esophago-gastric junction and the distal esophageal
body compared to healthy controls has been reported
in an impedance planimetry study of patients with
volumes. Intrabag pressure rises, however, resulting in a low
distensibility at volumes of 40- and 50 ml, respectively
eosinophilic esophagitis (Kwiatek et al. 2011). Eosinophilic esophagitis is managed by topical corticosteroid
therapy and exclusion of foods that a patient has an
allergic reaction to. In addition, balloon dilatation of
esophageal strictures may be required. The clinical role
of impedance planimetry in the workup of eosinophilic
esophagitis is less a purely diagnostic test as findings
are not exclusive to this condition. More importantly,
EndoFLIP
Ò
procedures can beperformed to monitorthe
success of balloon dilatation during a treatment session.
Fig. 3.
Attention should be paid to the progression of the
distensibility index with increasing bag volume. In
healthy subjects, in patients with hypertensive lower
esophageal sphincter, and possibly achalasia, distensibility tends to increase with filling volume of the
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Fig. 4 Distensibility of the pharyngo-esophageal junction in a
patient with graft-vs.-host disease after bone marrow transplantation for acute myeloid leukemia. A high-grade stenosis of
the pharyngo-esophageal junction and dilatation of the valleculae was seen in video-fluoroscopy. Distension with 20 ml bag
volume is displayed in 4a, while a filling volume of 40 ml was
measurement bag. In contrast, in conditions characterized by localized fibrosis—as in the case of a
Schatzki ring, eosinophilic esophagitis or peptic stenosis—the distensibility index may be normal or high
at low volumes and decreases after a plateau of the
cross-sectional area is reached. This consideration
applies to post-fundoplication dysphagia as well. In
the case of a tight fundic wrap, a similar degree of low
distensibility is seen over a length of several centimeters with increasing bag volume. In contrast, if the
hiatal closure is too narrow, the area of narrowing
shortens with increasing filling and the distensibility
index decreases.
Few data exist about the application of impedance
planimetry in the study of the pharyngo-esophageal
sphincter (Regan et al. 2012). To ascertain that the
airway is not compressed, maximal filling volume of
the measurement bag was limited to 20 ml in this
study. At rest, the pharyngo-esophageal sphincter was
not distended beyond the minimum diameter of
4.8 mm that the EndoFLIP
Ò
system can measure.
During deglutition, a maximal diameter of 9.2 mm for
dry swallows and 7.7 mm for 5 ml water swallows at
a bag volume of 20 ml was recorded, respectively. It
was also demonstrated that maneuvers such as head
turn and supraglottic swallow yield higher opening
diameters. However, the reported opening diameters
applied in 4b. The images depict distensibility at rest (left) and
during deglutition (right). The smallest diameter at rest was
5 mm for both volumes. Deglutition resulted in a narrowing of
the pharynx and a rise of intrabag pressure, but the smallest
diameter remained below 8 mm, respectively. This is indicative
of a highly rigid stenosis
of the pharyngo-esophageal junction during swallowing are surprisingly low with respect to bolus size
at meals. Higher filling volumes were not investigated
because of concerns that airway patency might be
compromised and because of poor tolerability of the
EndoFLIP
Ò
bag at this location. A similar maximal
diameter was described in a case report about a
patient with a high-grade pharyngo-esophageal stenosis after bone marrow transplantation and graftversus-host disease (Scharitzer et al. 2012). Fig. 4.
6 Impedance Planimetry in Patients
with Gastro-Esophageal Reflux
Disease
Gastro-esophageal reflux develops when the reflux of
gastric contents into the esophagus causes troublesome symptoms and/or complications. The diaphragmatic crura and the intrinsic lower esophageal
sphincter form an antireflux barrier. Transient lower
esophageal relaxations are the main mechanism for
reflux episodes. These vagally mediated drops of
pressure at the esophago-gastric junction mainly
occur in the postprandial period and are induced by
distension of the gastric fundus (Schoeman et al.
1995). If esophago-gastric junction anatomy is
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Fig. 5 Distensibility of the esophago-gastric junction in a
patient with gastro-esophageal reflux disease. The smallest
cross-sectional area increases with bag volume. The bag almost
disrupted and a hiatal hernia is present, a significant
proportion of reflux episodes may occur by other
mechanisms such as straining, deep inhalation or
swallow-induced sphincter relaxation (van Herwaarden et al. 2000). In an impedance planimetry study of
healthy controls versus subjects with symptomatic
gastro-esophageal reflux disease, the hiatal diameter
increased with increasing distention volume in both
groups. However, distension pressure was consistently lower in the group of reflux patients than in
control subjects at 20-, 30-, and 40-ml bag volumes.
At any given intrabag pressure, the opening of the
esophago-gastric junction was wider in reflux patients
(Kwiatek et al. 2010a). It can be deducted from these
findings that compliance of the esophago-gastric
acquires a cylindrical shape with 50 ml volume. Intrabag
pressure increases by a small extent only
junction may become a therapeutic target to prevent
excessive reflux. Fig. 5.
7 Application of Impedance
Planimetry During Therapeutic
Interventions
Antireflux surgery and gastric sleeve resection for the
treatment of morbid obesity are sometimes complicated by postoperative dysphagia. Bougies have been
used with inconsistent success to calibrate hiatal
closure and the fundic wrap. The application of
impedance planimetry during these operations may be
a promising approach. With this technique, surgery
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can be tailored so that the desired endoluminal
diameter is maintained at a low distension pressure.
The use of EndoFLIP
Ò
as a ‘‘smart bougie‘‘ during
antireflux surgery is currently investigated as recently
reported (Perretta et al. 2011). Intra-abdominal pressure induced by pneumoperitoneum during laparoscopic surgery has an impact on the distensibility of
the esophago-gastric junction, while the effects of
general anesthesia and muscle relaxation were
reported to be minimal (Nathanson et al. 2012).
Impedance planimetry during sessions of balloon
dilatation of esophageal strictures or of the esophagogastric junction in achalasia may be useful as well. In
contrast to radiological transit studies, this investigation
can be performed with the patient still under anesthesia
andrepeattreatmentsarepossiblein the samesessionifa
satisfactory effect has not been achieved.
8 The role of Impedance Planimetry
in Clinical Management of Patients
If symptoms of possible esophageal origin develop in a
patient, organ morphology and the state of the mucosal
lining are of principal interest. Video-fluoroscopy and
endoscopy cover these aspects to a large extent. If
mucosal integrity is preserved, and tumors or structural
lesions are excluded, functional disorders have to be
considered. Manometry and intraluminal impedance
monitoring are sophisticated tools to assess muscular
function and bolus clearance. Compliance of the organ
wall becomesthe center of interestif transport function
is impaired despite adequate peristalsis. Impedance
planimetry has a diagnostic role in the clinical work-up
of esophageal dysphagia. At present, it is the only
diagnostic toolavailable for clinical routine toexamine
mechanical wall properties in vivo. As such, it complements endoscopy, video-fluoroscopy and manometry. The response of the esophageal wall to different
distension volumes yields information on whether
dysfunction isdue to muscular versus connectivetissue
components. The effect of deglutition on distensibility
of the sphincteric regions and the esophageal body has
yet to be studied by impedance planimetry.
A role of impedance planimetry in the clinical workup of patients complaining of heartburn or regurgitation
has not been establishedso far. However,if dysphagia is
present in addition to typical reflux symptoms, esophageal manometryand an EndoFLIP
Ò
procedure may help
to distinguish between reflux-associated hypomotility
and the presence of a fibrotic ring as cause of the swallowing disorder.
In addition, impedance planimetry is successfully
used to tailor and monitor therapeutic procedures such
as fundoplication for treatment of gastro-esophageal
reflux disease as well as cardiomyotomy and pneumatic dilatations for achalasia. In these applications it
is superior to radiology since it can be performed
during anesthesia.
9 Summary
Impedance planimetry is an imaging technique to
characterize distensibility of hollow viscera that has
recently become available for clinical application.
Small sets of normative data have been published
regarding distensibility measurements of the esophago-gastric junction, the esophageal body and the
pharyngo-esophageal junction.
Esophageal dysphagia is the main application of
impedance planimetry for clinical purposes at present.
In patients with achalasia or eosinophilic esophagitis,
distensibility of the esophago-gastric junction is
reduced compared to healthy controls.
Impedance planimetry is indicated if bolus transport
through the esophagusisimpaired despite normalmotility
and preserved mucosal integrity. Decreasing distensibility of the esophago-gastric junction with increasing distension volume is indicative of local fibrosis.
In patients with gastro-esophageal reflux disease,
esophago-gastric-junction distensibility is increased
compared to healthy subjects.
Impedance planimetry is used for tailoring of
surgical procedures at the esophago-gastric junction
and for ad hoc monitoring of the effects of endoscopic
interventions.
References
Kwiatek MA, Pandolfino JE, Hirano I, Kahrilas PJ (2010a)
Esophagogastric junction distensibility assessed with an
endoscopic functional luminal imaging probe (EndoFLIP).
Gastrointest Endosc 72:272–278
Kwiatek MA, Kahrilas K, Soper NJ, Bulsiewicz WJ,
McMahon BP, Gregersen H, Pandolfino JE (2010b) Esoph-
agogastric junction distensibility after fundoplication
assessed with a novel functional luminal imaging probe.
J Gastrointest Surg 14:268–276
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Kwiatek MA, Hirano I, Kahrilas PJ, Rothe J, Luger D,
Pandolfino JE (2011) Mechanical properties of the esophagus in eosinophilic esophagitis. Gastroenterol 140:82–90
Liacouras CA,FurutaGT,HiranoI,AtkinsD,AttwoodSE,BonisPA,
Burks AW, Chehade M, Collins MH, Dellon ES, Dohil R,
Falk GW, Gonsalves N, Gupta SK, Katzka DA, Lucendo AJ,
Markowitz JE, Noel RJ, Odze RD, Putnam PE, Richter JE,
Romero Y, Ruchelli E, Sampson HA, Schoepfer A, Shaheen NJ,
Sicherer SH, SpechlerS, SpergelJM, StraumannA, Wershil BK,
Rothenberg ME, Aceves SS (2011) Eosinophilic esophagitis:
updated consensus recommendations for children and adults.
J Allergy Clin Immunol 128:3–20
Nathanson LK, Brunott N, Cavallucci D (2012) Adult esoph-
agogastric junction distensibility during general anesthesia
assessed with an endoscopic functional luminal imaging
probe (EndoFLIP
Perretta S, Dallemagne B, McMahon B, D’Agostino J, Maresc-
aux J(2011)Video. Improving functionalesophagealsurgery
with a ‘‘smart’’ bougie: Endoflip. Surg Endosc 25:3109
Ò
). Surg Endosc 26:1051–1055
Regan J, Walshe M, Rommel N, McMahon BP (2012) A new
evaluation of the upper esophageal sphincter using the
functional lumen imaging probe: a preliminary report. Dis
Esophagus. doi:10.1111/j.1442-2050.2012.01331.x
Rohof WO, Hirsch DP, Kessing BF, Boeckxstaens GE (2012)
Efficacy of Treatment for Patients with Achalasia Depends
on the Distensibility of the Esophagogastric Junction.
Gastroenterology May 2. [Epub ahead of print]
Scharitzer M, Denk-Linert D (2012). Case 28. Difficult
evaluation and treatment of an upper esophageal stenosis.
http://www.hon.ch/cgi-bin/OESO/myOESO.pl?selogguer
Schoeman MN, Tippett MD,Akkermans LM,DentJ,HollowayRH
(1995) Mechanisms of gastroesophageal reflux in ambulant
healthy human subjects. Gastroenterol 108:83–91
van Herwaarden MA, Samsom M, Smout AJ (2000). Excess
gastroesophageal reflux in patients with hiatus hernia is
caused by mechanisms other than transient LES relaxations.
Gastroenterology;119:1439–1446
Radiologic Evaluation of Esophageal
https://t.me/med1917
Function
Wolfgang Schima, Edith Eisenhuber,
and Christiane Kulinna-Cosentini
Contents
1 Introduction.............................................................. 339
2 Normal Function of the Esophagus
and the Lower Esophageal Sphincter ................... 340
2.1 Primary and Secondary Peristalsis............................ 340
2.2 Nonpropulsive (or Tertiary) Contractions ................ 340
2.3 Radiologic Evaluation of Esophageal Motor
Function ..................................................................... 340
3 Examination Technique .......................................... 341
4 Esophageal Motility Disorders............................... 343
5 Primary Motor Disorders....................................... 343
5.1 Achalasia.................................................................... 343
5.2 Pseudoachalasia (Malignancy-Induced Achalasia)... 344
5.3 Diffuse Esophageal Spasm........................................ 346
5.4 Nutcracker Esophagus ............................................... 347
5.5 Esophageal Atresia .................................................... 347
5.6 Nonspecific Esophageal Motor Disorders ................ 347
5.7 Presbyesophagus........................................................ 347
6 Secondary Motility Disorders ................................ 348
6.1 Progressive Systemic Sclerosis and Other
Connective Tissue Diseases ...................................... 348
6.2 Diabetes Mellitus ....................................................... 349
6.3 Chagas Disease .......................................................... 349
W. Schima (&)
Department of Radiology,
Krankenhaus Goettlicher Heiland,
Dornbacher Strasse 20–28,
1170 Vienna, Austria
e-mail: wolfgang.schima@khgh.at;
wolfgang.schima@meduniwien.ac.at
E. Eisenhuber
Krankenhaus Goettlicher Heiland,
Dornbacher Strasse 20–28, 1170 Vienna, Austria
C. Kulinna-Cosentini
Department of Radiology, Medical University of Vienna,
Währinger Gürtel 18–20, 1090 Vienna, Austria
6.4 Other Secondary Motility Disorders......................... 350
7 Esophageal Diverticula Associated with Motility
Disorders................................................................... 350
7.1 Midesophageal Diverticula ...................................... 350
7.2 Epiphrenic Diverticula............................................... 351
8 Gastroesophageal Reflux Disease and Esophageal
Function .................................................................... 351
8.1 Hiatal Hernia and Reflux .......................................... 351
8.2 Gastroesophageal Reflux
and Esophageal Function .......................................... 352
9 Dynamic Magnetic Resonance Imaging To Assess
Esophageal Motor Function ................................... 353
References.......................................................................... 354
Abstract
In patients with dysphagia, radiographic studies
evaluate both esophageal morphology and esophageal function. Videofluoroscopy accurately diagnoses achalasia, diffuse esophageal spasm, and PSS
(scleroderma). Videofluoroscopy is less sensitive
for the study of nonspecific motor disorders and
gastroesophageal reflux. When accuracy, costs,
availability, and patient acceptance are considered
(Parkman et al. Dig Dis Sci 41:1355–1368, 1996),
videofluoroscopy should be the initial diagnostic
test for patients with esophageal dysphagia.
1 Introduction
Radiologic assessment of the esophagus is an essential
part of the diagnostic workup of patients with deglutition
disorders. The radiologic examination comprises two
parts: single-and double-contrast examinations to assess
O. Ekberg (ed.), Dysphagia, Medical Radiology. Diagnostic Imaging, DOI: 10.1007/174_2011_345,
Ó Springer-Verlag Berlin Heidelberg 2012
339
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the morphology of the esophagus and the esophagogastric junction, which may reveal signs of esophagitis,
tumor, strictures, or rings. Radiologic evaluation of the
esophagus would be incomplete without assessing
esophageal function. Attempts to diagnose esophageal
motor dysfunction, such as achalasia, were undertaken in
the early days of single-contrast barium radiology (Hurst
and Rake 1930). The development of cinefluoroscopy
and videofluoroscopy has significantly improved the
ability to study the motor function of the pharynx and
esophagus in detail. The pharyngeal and esophageal
transport ofliquid andsolid bolusescan bestudied inreal
time and in slow motion. Although slow motion analysis
ismorecrucialfortheassessmentofpharyngealfunction,
video recording of esophageal bolus transport is also
essential for a thorough analysis of the esophagus. Subtle
abnormalities of motor function may go undetected
during real-time observation of swallowing.
2 Normal Function of the Esophagus
and the Lower Esophageal
Sphincter
The esophagus is a tubular muscular structure, measuring approximately 23 cm in length (Li et al. 1994),
which comprises outer longitudinal and inner circular
muscle fibers. The proximal part of the esophagus consists of striated muscle fibers, whereas the distal part is
composed of smooth muscle. The level of the transition
zone between striated and smooth muscle is highly
variable, with only the proximal 4 cm of the esophagus
always composed of striated muscle. This dual structure
of the esophageal musculature comprising striated
muscle and smooth muscle fibers is significant in diseases that selectively affect either striated or smooth
muscle. At the distal end of the esophagus, the tubular
esophagus widens to the vestibular esophagus.
The lower esophageal sphincter between the vestibular esophagus and the stomach measures 3–5 cm in
length. The lower esophageal sphincter corresponds to
the high-pressure zone at the esophagogastric junction
seen during esophageal manometry (Cohen 1979).
2.1 Primary and Secondary Peristalsis
Swallowing of a bolus triggers a primary peristaltic
contraction wave in 95–96% of patients (Richter et al.
1987), and this propagates with a velocity of
2–3.5 cm/s. Manometric studies have revealed that
the lower esophageal sphincter has a resting pressure.
Upon swallowing, the sphincter relaxes some seconds
after triggering of swallowing. Radiologically, the
lower esophageal sphincter is pushed open by the
bolus arriving at the gastroesophageal junction
(Dodds 1977). Immediately after bolus passage, the
sphincter recontracts (Dodds 1977). The amplitude
and propagation velocity of primary peristalsis are
modulated by bolus consistency, volume, and
temperature (Dooley et al. 1988). If there is residual
bolus in the esophagus or if there is a gastroesophageal reflux, a secondary peristaltic contraction wave
can be triggered by the volume remaining in the
esophagus to clear the esophagus. Both primary and
secondary esophageal contractions are peristaltic and
considered normal.
2.2 Nonpropulsive (or Tertiary)
Contractions
Nonpropulsive (or tertiary) contractions may also be
seen in the esophagus during videofluoroscopy or
manometry. They result in segmental muscular
contractions, which do not propagate to the distal
esophagus. They may occur simultaneously at multiple sites and they may be repetitive. They occur
spontaneously or may be triggered by swallowing or
other stimuli, such as acoustic emissions (Stacher
et al. 1979). In young adults, these nonpropulsive
contractions are rarely seen upon swallowing (Richter
et al. 1987). The prevalence and severity of nonpropulsive contractions increase with age (Grishaw et al.
1996). Most often, they are signs of abnormal
esophageal function.
2.3 Radiologic Evaluation of Esophageal
Motor Function
Radiologic evaluation of esophageal function always
includes assessment of the esophageal body as well as
the pharyngoesophageal and lower esophageal
sphincters. In contrast to the assessment of pharyngeal
function, esophageal peristalsis can be assessed in real
time. However, videotaping of a study is helpful to
allow repeated analysis of bolus transport that would
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demonstrate subtle abnormalities. Esophageal function should be assessed in all patients who suffer from
dysphagia or globus sensation when they are referred
for a videofluoroscopic study. One must be careful in
patients with clinically suspected aspiration. The
study should always be initiated with an examination
of pharyngeal function. If there is only laryngeal
penetration or minimal aspiration of the contrast
material, the examiner can proceed to assess esophageal function. In general, the use of intravenously
administered glucagon or BuscopanÒ should be
avoided. Glucagon and Buscopan can alter the
esophageal bolus transit and produce relaxation of the
gastroesophageal sphincter, resulting in spontaneous
gastroesophageal reflux (Anvari et al. 1989). For
esophageal motor function studies, low-density
barium (approximately 100% g/v) should be used.
Barium at this consistency flows easily and is radioopaque enough to provide good contrast in the
esophagus. Since it is known that bolus viscosity
alters peristalsis, thick high-density barium or barium
paste should not be used. In the case of aspiration, a
limited study of esophageal function with iodinated,
nonionic contrast material may be considered.
For assessment of esophageal peristalsis, the
observation of ‘‘single swallows’’ is essential.
Repetitive swallowing inhibits the propagation of
esophageal peristalsis (Meyer et al. 1981), a phenomenon, which is referred to as ‘‘deglutitive inhibition.’’ If the patient swallows repeatedly within
5–10 s, every new peristaltic contraction generated by
swallowing will inhibit the preceding peristaltic
contraction. Radiologically, this may be misinterpreted as impaired peristalsis or nonpropulsive contractions. After the end of a series of repeated
swallows, a large contraction wave will ‘‘clear’’ the
esophagus. Therefore, the size of the bolus administered is critical for assessment of esophageal peristalsis: we routinely use a bolus size of 10 ml of
barium to ensure that the patient swallows only once.
In contrast, rapid repetitive swallows maximally
distend the esophagus for morphologic evaluation
(e.g., the search for Schatzki rings).
Esophageal peristalsis is assessed with the patient
in the upright and in the prone oblique position.
Usually, swallows in the prone oblique position provide more information, because gravity does not
support bolus transit. The peristaltic contraction wave
occludes the esophageal lumen, giving the bolus tail
typically an inverted-V shape (Fig. 1). It propels the
complete bolus through the esophagus into the
stomach. The proximal escape of a small amount of
barium is not considered abnormal (Schima et al.
1992). Swallows in the upright position are some-
times of value because they may reveal subtle motor
abnormalities not seen in the prone oblique position
(Sears et al. 1989). In the upright position, bolus
transit through the esophagus is normally rapid. The
persistence of an air–fluid level (‘‘support level’’) is
indicative of the presence of a disordered motor
function or a stenosis (Schober et al. 1993).
The use of up to ten swallows per patient during
videofluoroscopy has been shown to be more sensitive
for the detection of subtle motor abnormalities
(Hewson et al. 1990); however, in clinical practice,
the number of swallows observed must be limited
because of radiation exposure, practicability, and
patient comfort. Therefore, our routine examination
protocol includes the observation of one bolus with
the patient in the upright position and three boluses
with the patient in the prone oblique position. The
diagnostic value of videofluoroscopic studies can be
increased by using solid barium-soaked marshmallows or globules, tablets, or rice (Aksglaede et al.
1992; Schwickert et al. 1993; Ott et al. 1991; Hannig
et al. 1990).
3 Examination Technique
1. Upright position, left posterior oblique: The
patient takes a bolus of low-density barium and is
asked to swallow only once. The left posterior
oblique position is preferred to avoid superposition
of the esophagus by the spine and to provide better
visualization of the gastroesophageal segment
(Schima et al. 1995).
2. After the table has been tilted, the patient is turned
to a prone oblique position. The patient takes a
bolus with a straw. Up to three swallows are
recorded. Imaging is centered on the tail of the
bolus to look for proximal escape and stasis of
the barium.
3. Assessment of the gastroesophageal reflux: Reflux
may or may not occur spontaneously during the
examination. There are also provocative tests to
elicit gastroesophageal reflux, including placing
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