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1281

EDUCATION EXHIBIT



Christine M. Peterson, MD • John S. Anderson, MD • Amy K. Hara, MD 

Jeffrey W. Carenza, MD • Christine O. Menias, MD

Volvulus of the gastrointestinal tract, a clinically relevant cause of 

acute or recurring abdominal pain in adults, remains a diagnostic di-

lemma for radiologists in a large number of cases. The clinical symp-

toms associated with volvulus are often nonspecifi c and include pain 

and nausea with vomiting. Yet referring clinicians often rely on radi-

ologists to make the diagnosis; volvulus is rarely diagnosed clinically. 

Radiography, fl uoroscopy, and computed tomography are the imaging 

methods most often used for this purpose. Prompt diagnosis is critical 

to avoid life-threatening complications such as bowel ischemia and in-

farction. Thus, it is useful for radiologists to be familiar with the vari-

ous appearances of volvulus throughout the gastrointestinal tract.

©

RSNA, 2009 • radiographics.rsna.org



Volvulus of the 

Gastrointestinal Tract: 

Appearances at Multi-

modality Imaging

1

ONLINE-ONLY

CME

See www.rsna

.org/education

/rg_cme.html

LEARNING


OBJECTIVES

After reading this 

article and taking 

the test, the reader 

will be able to:

List the risk fac-

 



tors for develop-



ment of volvulus of 

the stomach, small 

bowel, and colon.

Identify the most 

 



common imag-



ing appearances 

of gastrointestinal 

volvulus.

Describe common 

 



subtypes of volvulus 



of the stomach and 

colon.


Abbreviation:  GI = gastrointestinal

RadioGraphics 2009; 29:1281–1293 • Published online 10.1148/rg.295095011 • Content Code: 

 

1

From the Department of Radiology, Penn State College of Medicine, Penn State Milton S. Hershey Medical Center, 500 University Dr, H066, Her-



shey, PA 17033-0850 (C.M.P.); Colorado Permanente Medical Group, Denver, Colo (J.S.A.); Department of Diagnostic Radiology, Mayo Clinic, 

Scottsdale, Ariz (A.K.H.); Texas Radiology Associates, Plano, Tex (J.W.C.); and Mallinckrodt Institute of Radiology, Washington University School 

of Medicine, St Louis, Mo (C.O.M.). Presented as an education exhibit at the 2006 RSNA Annual Meeting. Received January 15, 2009; revision 

requested February 11 and received June 16; accepted June 17. A.K.H. has license and research agreements with General Electric; all other authors 

have no fi nancial relationships to disclose. Address correspondence to C.M.P. (e-mail: cpeterson3@hmc.psu.edu).

©

RSNA, 2009



See last page

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Figure 2.  Mesenteroaxial volvulus. Diagram shows 

the stomach twisting along its short axis. A = gastric 

antrum, GEJ = gastroesophageal junction.

Figure 1.  Organoaxial volvulus. Diagram shows 

the rotation of the stomach along its long axis. GC = 

greater curvature, LC = lesser curvature.

Introduction

Volvulus of the gastrointestinal tract, a clinically 

relevant cause of acute or recurring abdominal 

pain in adults, often poses a diagnostic dilemma 

for radiologists. The clinical symptoms associ-

ated with volvulus commonly are nonspecifi c and 

include pain, nausea, and vomiting. Because it is 

rarely diagnosed clinically, clinicians often con-

sult radiologists for diagnostic evaluations; radi-

ography, fl uoroscopy, and computed tomography 

(CT) are the modalities most frequently em-

ployed. Prompt diagnosis is critical to avoid life-

threatening complications of prolonged volvulus 

such as bowel ischemia and infarction. This ar-

ticle highlights the different clinical features and 

common imaging fi ndings of volvulus throughout 

the gastrointestinal tract.

Gastric Volvulus

The stomach is a relatively uncommon site of 

volvulus. Patients with acute gastric volvulus typi-

cally present with epigastric pain, nausea, and 

vomiting. A useful clinical triad for identifying 

gastric volvulus, the Borchardt triad consists of 

sudden epigastric pain, intractable retching, and 

inability to pass a nasogastric tube into the stom-

ach (1).

Gastric volvulus is usually divided into two 

main subtypes: organoaxial and mesenteroaxial. 

Organoaxial volvulus is far more common than 

mesenteroaxial volvulus and accounts for ap-

proximately two-thirds of cases of gastric volvu-

lus. Both are surgical emergencies and warrant 

prompt diagnosis and treatment.

Organoaxial volvulus occurs when the stom-

ach rotates along its long axis and becomes 

obstructed, with the greater curvature being dis-

placed superiorly and the lesser curvature located 

more caudally in the abdomen (1–3).

 The antrum 

rotates anterosuperiorly, and the fundus rotates 

posteroinferiorly. In adults, organoaxial volvulus 

most commonly occurs in the setting of a post-

traumatic or paraesophageal hernia that allows 

the stomach to move abnormally along its long 

axis (4). If the volvulus is severe or complete—

meaning that the twist is greater than 180

°—gas-


tric outlet obstruction occurs, and the stomach 

becomes dilated and fi lls with fl uid. If positive 

oral contrast material is administered, it is re-

tained in the stomach.

 However, many patients 

have a less severe, incomplete or partial volvu-

lus—a rotation of less than 180

°. In these cases, 

ingested contrast material may pass through the 

stomach and into the duodenum. Patients with a 

redundant paraesophageal hernia are predisposed 

to developing a secondary rotation of the stom-

ach along its long axis. These patients usually 

lack clinical symptoms of obstruction and exhibit 

no evidence of obstruction at imaging. In such 

cases, it is more accurate to describe the stomach 

as having an organoaxial position rather than an 

organoaxial volvulus, although an organoaxial 

position of the stomach predisposes it to future 

volvulus. It is unclear whether asymptomatic pa-

tients should be treated or followed up clinically. 

In general, the acuity and severity of symptoms 

dictate management. In children, a large Boch-

dalek hernia is a predisposing factor for gastric 

volvulus (Fig 1) (4).

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RG    Volume 29  •  Number 5 

Peterson et al  1283

gastric volvulus, with both organoaxial and mes-

enteroaxial components.

Radiographic fi ndings of gastric volvulus in-

clude herniation of a large portion of the stom-

ach above the diaphragm, often with differential 

air-fl uid levels (5). An upper gastrointestinal 

(GI) series may be performed to evaluate the 

rotation of the stomach, as well as to detect 

passage of ingested oral contrast material into 

the duodenum. Multi–detector row CT often is 

performed in the setting of epigastric pain and 

vomiting and can help confi rm the rotation of 

the herniated stomach and the transition point 

(Figs 3–5).

If a diagnosis is made and surgical repair is 

performed soon after the onset of symptoms, 

gastric ischemia usually can be avoided. However, 

if there is a delay in patient presentation, diagno-

sis, or intervention, gastric ischemia may result, 



Figure 4.  Primary organoaxial volvulus in a new-

born. Upper GI image shows inversion of the greater 



(GC) and lesser (LC) curvatures of the stomach.

Figure 5.  Mesenteroaxial volvulus. Anteroposterior 

upper GI image shows displacement of the gastric an-

trum (A) above the gastroesophageal junction (arrow). 

The gastric body (B) and pylorus (P) also are seen. 



Figure 3.  Organoaxial volvulus. (a) Upper GI image shows an upward rotation of the stomach along its 

long axis, which results in inversion of the greater curvature (GC) above the lesser curvature (LC). Arrow = 

pylorus. (b) CT image shows the transverse lie of the stomach, which has herniated into the chest. Arrow = 

pylorus.


Mesenteroaxial volvulus is much less com-

mon than organoaxial volvulus. It occurs when 

the stomach rotates along its short axis, with 

resultant displacement of the antrum above the 

gastroesophageal junction (1–3). Rotation is usu-

ally partial (less than 180

°) and is not associated 

with an underlying diaphragmatic defect (Fig 

2).

 However, some patients may have a complex



 

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Figure 6.  Perforated gastric volvulus in a 73-year-old man with abdominal pain. Scout radiograph (a) and coronal 

CT image (b) show gastric distention and pneumoperitoneum (arrows in a) due to a perforated gastric volvulus, the 

presence of which was confi rmed at surgery. Perforation of a gastric volvulus is an uncommon complication that re-

sults from gastric ischemia. GC = greater curvature, LC = lesser curvature.



Figure 7.  Midgut volvulus in an infant. 

(a) Upper GI image shows that the small 

bowel lies in the right side of the abdomen 

and does not cross the midline. (b) Lateral 

upper GI image shows the typical twisting 

corkscrew-like appearance of a volvulus 

of the proximal jejunum. (c) Lateral up-

per GI image obtained in a different pa-

tient also shows the classic corkscrew-like 

appearance.


RG    Volume 29  •  Number 5 

Peterson et al  1285

Figure 8.  Midgut volvulus in a patient with cardiovascular collapse. CT images (b is slightly more caudal than a

obtained emergently show bowel dilatation and mucosal hyperattenuation, fi ndings indicative of global small-bowel 

ischemia. There is a twist at the root of the small-bowel mesentery, and an abnormal relationship between the supe-

rior mesenteric artery (long arrow) and the superior mesenteric vein (short arrow) is seen.

which can lead to necrosis, perforation, medias-

tinitis, and peritonitis (Fig 6).



Midgut Volvulus

Midgut volvulus is a different clinical entity and 

is most common in children; 60%–80% of those 

affected present with bilious vomiting in the 1st 

month of life (6). However, as the use of CT in 

emergency departments increases, midgut volvu-

lus is increasingly being recognized in adults.

Malrotation of the small bowel is the major 

predisposing factor for midgut volvulus. In a mal-

rotation, there is abnormal fi xation of the small 

bowel mesentery, which results in an abnormally 

short mesenteric root. This allows the small bowel 

to twist around its mesentery, causing obstruction 

and possibly ischemia of the bowel. Midgut volvu-

lus often occurs early in life, and in such cases sur-

gery is performed to repair the malrotation.

 How-

ever, volvulus also may occur in adulthood, and in 



some cases may manifest as chronic intermittent 

abdominal pain that resolves when the volvulus 

spontaneously reduces. If it does not spontane-

ously reduce, patients at any age may present with 

abdominal pain, nausea, and vomiting (1,7).

Conventional radiography usually yields non-

specifi c fi ndings and is rarely helpful in making a 

diagnosis. On the other hand, fl uoroscopic upper 

GI and small-bowel examinations may reveal the 

characteristic abnormal position of most of the 

small bowel in the right abdomen and the resultant 

abnormal location of the ligament of Treitz. These 

are usually the preferred imaging tests when midgut 

volvulus is suspected. On upper GI images, the liga-

ment of Treitz normally is located at or to the left of 

the left L1 pedicle. In patients with malrotation, the 

ligament of Treitz is abnormally positioned, usually 

below and to the right of the left L1 pedicle. In the 

presence of a midgut volvulus, the twisted segment 

(usually a proximal segment) of small bowel has a 

characteristic corkscrew-like appearance on fl uoro-

scopic images (Fig 7) (6).

Ultrasonography (US) is sometimes helpful in 

that an abnormal positional relationship between 

the superior mesenteric vein and artery may be 

appreciated, with the vein located to the left of 

the artery, which is the opposite of its usual ori-

entation (6,8). However, US does not directly 

show the abnormal position of the bowel and is 

rarely used in this clinical setting.

Familiarity with the CT fi ndings of midgut 

volvulus is important, because many patients 

present with nonspecifi c symptoms and are fi rst 

evaluated with cross-sectional imaging. At CT, 

a swirling of vessels in the mesenteric root may 

be seen at the site of the volvulus (6,7,9). The 

abnormal relationship between the superior mes-

enteric artery and vein, an ectopic location of the 

majority of small bowel loops, and an abnormal 

position of the ligament of Treitz (which was de-

scribed earlier) also may be seen (Fig 8).

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Figure 10.  Cecal volvulus in an elderly woman with abdominal pain. (a) Coronal reformatted CT 

image shows dilated cecum (arrow) in the left upper quadrant of the abdomen. The cecum is displacing 

the contrast material–fi lled stomach superiorly, and there is obstruction of the small bowel. (b) Axial 

CT image shows that the dilated cecal loop (arrow) has twisted on its mesentery and is located ectopi-

cally in the upper abdomen.

are less common and also may predispose pa-

tients to cecal volvulus (1,10).

As opposed to volvulus in other locations, 

colonic volvulus often has a characteristic ap-

pearance at conventional radiography, which may 

be suffi cient for a diagnosis in a large percentage 

of patients.

 A dilated gas-fi lled viscus, usually 

located ectopically in the left upper quadrant or 

mid abdomen, is a radiographic feature of cecal 

volvulus. However, it is important to recognize 

that the cecum may be displaced anywhere in the 

abdomen (11). Proximal obstruction may or may 



Colonic Volvulus

Cecum

Cecal volvulus accounts for 25%–40% of all 

cases of colonic volvulus. Congenital anomalies 

of colonic fi xation usually are present and include 

an abnormal fi xation of the right colon to the ret-

roperitoneum and abnormal motility of the right 

colon. Factors that result in dilatation of the right 

colon, such as pregnancy and recent colonoscopy, 



Figure 9.  Cecal volvulus in a 74-year-

old woman with abdominal pain. Ra-

diograph shows dilated air-fi lled cecum 

(arrow) in the left upper quadrant.



RG    Volume 29  •  Number 5 

Peterson et al  1287

Figure 12.  Cecal volvulus in an elderly patient with abdominal cramps. (a) CT image shows dilated 

fl uid-fi lled cecum in the lower abdomen. The proximal small bowel also is dilated. (b) Image acquired in a 

contrast material enema study shows the classic beaklike appearance of the bowel at the twist (arrow).

Figure 11.  Cecal volvulus. Contrast-

enhanced CT image shows dilated, 

fl uid- and gas-fi lled cecum at the lower 

midline. Pneumatosis of the cecum (ar-

rows) also is seen. The diagnosis was 

confi rmed at exploratory surgery.

patients with suspected cecal volvulus proceed 

to CT if further imaging is required. At CT, 

the abnormally positioned cecum often appears 

in the upper mid and left abdomen and can be 

traced back to the level of the volvulus, which 

appears as an area of swirling of the bowel 

and its mesentery, a fi nding also known as the 

“whirl” sign (Figs 11–16) (12).

Cecal bascule, fi rst described in the early 

1900s, refers to abnormal location of the dilated 

cecum in the mid abdomen and results from up-

ward folding of the cecum on itself, without as-

sociated twisting. Cecal bascule occurs when the 

cecum is loosely attached to its mesentery. Some 

not be present, depending on the acuity of the 

volvulus (Figs 9, 10) (1).

A diagnosis of cecal volvulus often is con-

fi rmed with a contrast material enema study or 

CT. During the enema, the distal colon usually 

is decompressed, and there is a beaklike taper-

ing at the level of the volvulus. It usually is not 

possible for much contrast material to pass 

beyond the volvulus into the more dilated proxi-

mal colon and terminal ileum. For patients in 

whom cecal volvulus is suspected on the basis of 

radiographic fi ndings, a contrast material enema 

study may help confi rm the diagnosis. However, 

given the widespread availability of CT and the 

relative speed with which it can be performed 

compared with that of the enema study, most 



Teaching

Point

RG    Volume 29  •  Number 5 

Peterson et al  1287

Figure 12.  Cecal volvulus in an elderly patient with abdominal cramps. (a) CT image shows dilated 

fl uid-fi lled cecum in the lower abdomen. The proximal small bowel also is dilated. (b) Image acquired in a 

contrast material enema study shows the classic beaklike appearance of the bowel at the twist (arrow).

Figure 11.  Cecal volvulus. Contrast-

enhanced CT image shows dilated, 

fl uid- and gas-fi lled cecum at the lower 

midline. Pneumatosis of the cecum (ar-

rows) also is seen. The diagnosis was 

confi rmed at exploratory surgery.

patients with suspected cecal volvulus proceed 

to CT if further imaging is required. At CT, 

the abnormally positioned cecum often appears 

in the upper mid and left abdomen and can be 

traced back to the level of the volvulus, which 

appears as an area of swirling of the bowel 

and its mesentery, a fi nding also known as the 

“whirl” sign (Figs 11–16) (12).

Cecal bascule, fi rst described in the early 

1900s, refers to abnormal location of the dilated 

cecum in the mid abdomen and results from up-

ward folding of the cecum on itself, without as-

sociated twisting. Cecal bascule occurs when the 

cecum is loosely attached to its mesentery. Some 

not be present, depending on the acuity of the 

volvulus (Figs 9, 10) (1).

A diagnosis of cecal volvulus often is con-

fi rmed with a contrast material enema study or 

CT. During the enema, the distal colon usually 

is decompressed, and there is a beaklike taper-

ing at the level of the volvulus. It usually is not 

possible for much contrast material to pass 

beyond the volvulus into the more dilated proxi-

mal colon and terminal ileum. For patients in 

whom cecal volvulus is suspected on the basis of 

radiographic fi ndings, a contrast material enema 

study may help confi rm the diagnosis. However, 

given the widespread availability of CT and the 

relative speed with which it can be performed 

compared with that of the enema study, most 



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Figure 14.  The whirl sign of cecal volvulus. (a) Contrast-enhanced CT image shows a dilated, stool-fi lled cecum 

in the left upper quadrant of the abdomen (arrow). (b) Contrast-enhanced CT image shows that the twist involves 

the ileum, which lies in the right lower quadrant (arrow). Note the whorled appearance of the mesenteric vessels 

within the twist. Mesenteric stranding and edema also are seen.



Figure 13.  Cecal volvulus. (a) Topographic CT image shows a dilated air-fi lled viscus in the midline (arrow) 

and a small-bowel obstruction. (b) Contrast-enhanced CT image shows displacement of the dilated fl uid-

fi lled cecum in the right upper quadrant (arrow), with resultant small-bowel obstruction.

Figure 15.  Infarcted cecal volvulus in a 

20-year-old woman. Contrast-enhanced CT 

image shows a dilated cecum located high in 

the midline. Note the ring of gas in the cecal 

wall (arrows), a fi nding suggestive of pneuma-

tosis. The diagnosis of an infarcted cecal vol-

vulus was confi rmed at exploratory surgery.


RG    Volume 29  •  Number 5 

Peterson et al  1289

Figure 16.  Cecal volvulus. Axial (a) and coronal (b) reformatted CT images show the distended cecum in the 

left upper quadrant of the abdomen (* in a). The mesenteric twist, which in this case involves the terminal ileum, is 

most easily seen within the circled area in b.

have argued that cecal bascule is a form of cecal 

adynamic ileus that may lead to perforation, de-

pending on duration of symptoms (13).



Transverse Colon

The transverse colon is the rarest site of colonic 

volvulus (

<5%–10% of cases), but it is associated 

Figure 17.  Transverse colon volvulus in a 57-year-old 

woman with a 7-year history of intermittent abdominal pain 

and a 30-year history of laxative use. (a, b) CT images (b is 

slightly more caudal than a) show a whirl sign adjacent to the 

transverse colon (arrow). (c) Image acquired during an en-

ema shows classic beaklike narrowing of the transverse colon 

at the volvulus (arrow).

with the highest mortality. It occurs in the setting 

of abnormal fi xation of a long transverse colon. 

Conventional radiography is seldom helpful in 

diagnosing this entity. As in cases of cecal volvu-

lus, a contrast material enema study shows the 

characteristic beaklike tapering of the colon at 

the level of the twist. However, because volvulus 

of the transverse colon is rare and not usually ex-

pected, the diagnosis is often made at CT, which 

shows bowel obstruction and the classic mesen-

teric twist (Fig 17).



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Figure 19.  Sigmoid volvulus. (a) Supine radiograph shows the sigmoid colon arising from the pelvis, with 

its apex in the left upper abdomen. The interposed loops produce the white-stripe sign (arrow). (b) Image 

acquired in a contrast material enema study shows abrupt termination of the contrast material column in a 

beaklike point.

cause of large-bowel obstruction in the absence 

of neoplasm and diverticular disease. However, in 

developing countries, sigmoid volvulus causes a 

majority of bowel obstructions and is presumably 

caused by relatively high-fi ber diets. It is also the 

most common cause of bowel obstruction during 

pregnancy.

Because patients usually present with nonspe-

cifi c abdominal pain and symptoms of obstruc-

tion, conventional radiography often is performed 

as part of the initial work-up. Radiographic fi nd-

ings that may be diagnostic of sigmoid volvulus 

include a large air-fi lled bowel loop, which rep-

Sigmoid Colon

The sigmoid is the most common site of colonic 

volvulus and accounts for 60%–75% of all cases 

of colonic volvulus. It is generally considered to 

be an acquired condition because its prevalence 

increases among those with chronic constipation 

and sigmoid colonic redundancy due to a high-

fi ber diet, pregnancy, hospitalization or institu-

tionalization, or Chagas disease (1,10,14). In de-

veloped countries, sigmoid volvulus is a common 



Figure 18.  “Northern exposure” sign in a 

52-year-old man with abdominal pain. Erect 

radiograph shows the displacement of the sig-

moid colon (arrow) above the transverse colon 



(Tr). This sign was fi rst observed as extension 

of the apex of the sigmoid colon cephalad to 

the transverse colon on supine radiographs.


RG    Volume 29  •  Number 5 

Peterson et al  1291

Figure 21.  Sigmoid volvulus. Coronal CT images obtained with soft-tissue (a) and lung (b) window 

settings show the whirl sign (arrow in a) and the classic beak sign (arrow in b) at the level of the twist. 

The diagnosis was confi rmed at endoscopy.

Figure 20.  Sigmoid volvulus in a 46-year-old woman with abdominal pain. (a) Radiograph shows an 

air-fi lled, dilated viscus (arrow) arising from the pelvis. (b) Coronal CT image shows the whirl sign in 

the sigmoid mesocolon (arrow). A contrast material enema study helped confi rm the diagnosis.

resents the sigmoid colon, arising from the pelvis 

and extending cranially beyond the level of the 

transverse colon (the “northern exposure” sign) 

(Figs 18–23) (10,15). Other useful radiographic 

features include the “coffee bean” sign, which re-

fers to the coffee bean–like shape that the dilated 

sigmoid colon may assume (10,16). Similarly, the 

“closed-loop” and “three-line” or “white-stripe” 


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Figure 23.  Sigmoid volvulus. (a) Radiograph shows a dilated viscus arising from the pelvis and 

ascending above the transverse colon. (b) CT image shows the site of the twist (arrow).



Figure 22.  Sigmoid volvulus. (a) Radiograph shows a dilated sigmoid colon arising from the 

pelvis, with its apex in the right upper quadrant of the abdomen (arrow). (b) Coronal CT image 

shows the characteristic whirl sign at the level of the volvulus (arrow).


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Figure 23.  Sigmoid volvulus. (a) Radiograph shows a dilated viscus arising from the pelvis and 

ascending above the transverse colon. (b) CT image shows the site of the twist (arrow).



Figure 22.  Sigmoid volvulus. (a) Radiograph shows a dilated sigmoid colon arising from the 

pelvis, with its apex in the right upper quadrant of the abdomen (arrow). (b) Coronal CT image 

shows the characteristic whirl sign at the level of the volvulus (arrow).

RG    Volume 29  •  Number 5 

Peterson et al  1293

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  4. Godshall D, Mossallam U, Rosenbaum R. Gastric 

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  5. Menuck L. Plain fi lm fi ndings of gastric volvulus 

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  6. McAlister WH, Kronemer KA. Emergency gastro-

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signs describe the U-shaped closed-loop appear-

ance of the colon, which is dilated between the 

two points of obstruction at the site of the volvu-

lus; and the obliquely oriented vertical white lines 

that represent the opposed walls of the dilated 

bowel loop (the center line) and the outer walls 

of the bowel loop on either side (11,17).

In cases in which the diagnosis is uncertain, 

a water-soluble contrast material enema study 

or CT may be performed. In an enema study, a 

beak-shaped area often is seen at the level of the 

distal aspect of the twist in the sigmoid, beyond 

which no contrast material passes. In addition to 

providing diagnostic information, the enema may 

help achieve reduction of the volvulus. At CT, 

the abnormal position of the sigmoid colon and 

swirling of the mesentery at the level of the volvu-

lus are visible. As with cases of volvulus involving 

other sites in the GI tract, coronal and sagittal 

reformations may be useful for locating the mes-

enteric swirl and evaluating the orientation of the 

rotated bowel segment.

Summary

Volvulus may involve any portion of the GI tract 

from the stomach to the colon and is an impor-

tant cause of acute or recurring abdominal pain. 

Because a delay in diagnosis can have devastating 

consequences, including bowel ischemia and in-

farction, prompt diagnosis is essential. The clini-

cal symptoms of volvulus often are nonspecifi c, 

and radiologists often are consulted for diagnos-

tic evaluations. This article describes the vari-

ous radiologic imaging appearances of volvulus 

throughout the GI tract, emphasizing strategies 

for achieving an accurate diagnosis.

References

  1. Feldman M, Scharschmidt BF. Sleisenger and 

Fordtran’s gastrointestinal and liver disease: 

pathophysiology/diagnosis/management. 6th ed. 

Philadelphia, Pa: Saunders, 1998; 324–328.

  2. Yamada T, Alpers DH, Owyang C, Powell DW, 

Silverstein FE, eds. Textbook of gastroenterology. 

Philadelphia, Pa: Lippincott, 1991; 1404–1407.



This article meets the criteria for 1.0 AMA PRA Category 1 Credit

TM

. To obtain credit, see 

www.rsna.org/education

/rg_cme.html.


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