NEW APPROACH TO ACUTE BOWEL OBSTRUCTION BY MULTIDETECTOR CT - PowerPoint Presentation

Slide1

NEW APPROACH TO ACUTE BOWEL OBSTRUCTION BY MULTIDETECTOR CT

A. SAIDANE*, A. DAGHFOUS*, M. FRIKHA*, S. FELAH*, A. ZOGHLEMI**, L. REZGUI MARHOUL*Radiology* and General surgery** services Trauma center, 1007 Tunis, Tunisia

GI24

Slide2

INTRODUCTION

Bowel obstruction is a leading cause of admission in surgical and emergency

units

.

A correct assessment of its severity, mechanism and causes is of primary importance in its management.

The

multidetector

CT is the main tool to achieve this purpose.

Our aim is to review the CT

semiology

and the different etiologies of acute bowel obstruction.

Slide3

MATERIALS & METHODS

A retrospective study of 30 patients admitted from 2008 to 2011 in the service of general surgery for acute bowel obstruction. All were explored by a 16 bars abdominal CT.

The acquisition volume goes from diaphragm to pubis with slices of 5 mm

thickeness

A first spire is performed without contrast then a second one is made at a portal time (60 to 70 sec)

Slide4

MATERIALS & METHODS

High intestinal opacification in 4 cases Low intestinal opacification

in 24 cases

Reconstruction in

sagittal

and coronal plans

10 have evolved under suction

20 patients were operated and a confrontation with surgical data was systematic

Slide5

RESULTS

About 60% of all cases were involved

in a

small

bowel

obstruction

Small

bowel

occlusion:

distended

loops

( ) with air-fluid levels ( ) nearby collapsed ( )or normal-caliber loops ( ) with visualization of a transition point

Slide6

RESULTS

Some signs made the

obstruction’s

level

diagnosis

easier

!!!

String of

pearls

signSmall bowel feces sign: colonic feces appearance found in the

small bowel

Slide7

RESULTS

The most common cause was adhesion in patients with

surgical

history

Beak

sign

: a

beak

form

ending of a distensed loop ( > )associated to a flat aspect of the loop coming after ( )

Slide8

RESULTS

Small bowel volvulus was

found

as a complication of

adhesion

and

its

main CT

finding

was

the

Whirl

sign Whirl sign: a twisting of the mesenteric vasculature

Slide9

RESULTS

n cases of

small

bowel

carcinoma

: n

carcinoid

tumor

+ n

adenocarcinoma

Heterogenous mass of the small bowell with arterial enhancement Carcinoid tumor

Irregular

stenosis

with heterogenous thickening of the

bowel wall

 Adenocarcinoma

Slide10

RESULTS

Crohn disease

was

suspected

in 4 cases

Coronal reconstruction:

Regular

stenosis

of the last

ileal

loop ( )Sclerolipomatosis ( ) Crohn disease

Slide11

RESULTS

Adenocarcinoma was the main cause of colonic obstruction

Irregular

stenosis

of the recto-

sigmoid

junction

Short

irregular

transverse colon

stenosis

seen

in axial and sagittal reconstruction

Slide12

RESULTS

Women

, 65

years

old

,

bowel

obstruction and pain in the LIF



Diverticular

sigmoiditis

Slide13

RESULTS

Only one case of bowel obstruction was related to an ileus secondary

to acute

appendicitis

Slide14

DISCUSSION

In case of bowel obstruction, CT has to answer 5 questions: Is that a true obstruction or not? What is its mechanism (functional or mechanical)?

What is its level (small or large bowel)?

Is there signs of severity?

Is there an evident cause?

Slide15

DISCUSSION

The positive diagnosis is based on the visualization of an intestinal distension greater than 25 mm for the small bowel and 50 mm for the colon proximally to normal-caliber or collapsed loops distally [1,2,3]. Functional obstruction, due to a reflex ileus, results in “hydro-pneumatic” levels that are rare, diffuse with predominance of gas images while a mechanical one leads to concentrated levels around the site of occlusion

Slide16

DISCUSSION

To put in evidence the level of occlusion, it is traditionally recommended  to find  the transition point between flat and distended intestine by following the digestive tract retrogradely departing from the rectum.That point of transition often described as a beak sign (as it ressembles a beak) make the diagnosis much more certain [4]

We may also use other CT signs as the feces sign and the string-of-pearls sign which are related to small bowel obstruction

Slide17

SEVERITY DIAGNOSIS

The sensitivity of contrast-enhanced CT for intestinal ischemia has been reported to be as high as 90% [5].There are various signs that have been associated with ischemia:

Thickened bowel wall : a sign of a limited value [6]

Ascites

Target sign, a

trilaminar

appearance of the bowel wall : very specific but rare [6]

Poor or absent enhancement of bowel wall on IV contrast-enhanced scans

Pneumatosis

intestinalis

Gas in mesenteric or portal veins

Increased attenuation of bowel wall on

noncontrast scan

Slide18

SEVERITY DIAGNOSIS

The pneumoperitoneum signs  bowel perforation which is the final stage of intestinal ischemiaBesides when the occlusion is due to a strangulation, the intestinal ischemia risk increases

CT signs of strangulation [1]:

Whirl sign,

a

twisting

of

the mesenteric vasculature signifying a

volvulus

Tortuous

engorged

mesenteric vesselsMesenteric hemorrhage

Slide19

CAUSES OF SMALL BOWEL OBSTRUCTION

STRANGULATION OF SMALL BOWEL[8]: Adhesion (70% of all SB obstruction[7]: The diagnosis is made when the patient has a surgical history and when all other causes of obstruction have been ruled out at CT (NB: do not forget that there is inflammatory, congenital and unexplained causes of adhesions). Small Bowel

Volvulus

:

a

circumferentially

thickened

loop

associated

to a

whirl sign Hernia: CT is useful in depicting the precise site and type of hernia and its contents, including spigelian, obturator, lumbar, and ventral hernias [8]

Slide20

EXTRINSIC MASSES[8]: Carcinoid

tumors: primarily intrinsic lesions of the ileum; but small bowel obstruction due to desmoplastic mechanisms operating in the mesentery which appears in CT as a nodular mass in association with retraction of surrounding bowel loopsLymphoma: espacially the non Hodgkin nodular form that arise in the mesentery

Peritoneal

Carcinomatosis

omental

mass in the transition zone

causing

obstruction

CAUSES OF SMALL BOWEL OBSTRUCTION

Slide21

INTRINSIC MASSES[8]:Adenocarcinoma

: usually manifests at an advanced age as mural thickening with luminal narrowing at the transition zone. CT also provides information about tumor extension & distant metastases.Crohn disease: in its advanced stenotic phaseTuberculosis: regional nodes +

thickenned

bowel wall

Others:

radiation

enteropathy

, intramural hematoma

CAUSES OF SMALL BOWEL OBSTRUCTION

Slide22

INTUSSUSCEPTION: Occlusive by both

a strangulation and obstuction mechanismSecondary to intramural polypoid tumors in

adults

Sausage

-

shaped

sign

and

target

sign

INTRAMURAL

CAUSES:Bezoars (intraluminal heterogenous mass), gallstones, foreign bodies, retained meconium, or tangles of ascaridesINTESTINAL MALROTATION:CT findings include right-sided small bowel, left-sided colon, abnormal relationships between superior mesenteric vessels, and

aplasia of the uncinate process. Obstruction by small

bowel volvulus

CAUSES OF SMALL BOWEL OBSTRUCTION

Slide23

CAUSES OF COLONIC OBSTRUCTION

OCCLUSIVE CANCER:[2]70% of cases Short stenosis without major overhauls of the pericolic fat

DIVERTICULAR SIGMOIDITIS:

7% of cases

Important 

pericolic

 inflammatory infiltration with or without

diverticula

COLONIC STRANGULATION:

Volvulus

of the sigmoid: Beak sign and Whirl sign

Caecal

volvulus: 1% of casesCOLORECTAL ENDOMETRIOSIS: a CT tumoral syndrom

Slide24

CONCLUSION

The diagnosis of bowel obstruction is based on a comprehensive approach that includes clinical background, patient history and conventional radiography.However, the ability to determine the site, level, cause, and severity of bowel obstruction with CT makes this modality an important additional diagnostic tool.

Slide25

REFERENCES

S.

Nicolaou

, B. Kai, S. Ho, Jenny Su, K.

Ahamed

.

Imaging of Acute Small-

Bowel

Obstruction.

AJR

2005; 185: 1036–1044

2) M.

Deneuville, S. Beot, F. Chapuis, Ch. Bazin, H. Boccaccini, D. Regent. Imagerie des occlusions intestinales aiguës de l'adulte. Traité de Radiodiagnostic IV - Appareil digestif : 33-710-A-10 (2004)3) K. Lebbar, D. Bassou, M. Drissi, T. Amil, M. Benameur. Les occlusions intestinales chez l’adulte: Intéret de la tomodensitométrie. Med Maghreb 2001; 87: 21-254) Furukawa A, Yamasaki

M, Furuichi K, et al. Helical CT in the diagnosis of small bowel obstruction. RadioGraphics

2001; 21:341–3555) Maglinte DDT, Heitkamp DE, Howard TJ, et al. Current concepts in imaging of small bowel obstruction.

Radiol Clin North Am 2003; 41:263–283

6) M. Zalcman, M. Sy, V. Donckier, J.

Closset, D. Van Gansbeke. Helical CT Signs in the Diagnosis of Intestinal

Ischemia in Bowel Obstruction. AJR 2000;175:1601–1607

7) Burkill GJC, Bell JRG, Healy JC. The utility of computed tomography in acute small bowel obstruction. Clin Radiol 2001; 56:350–359

8) M. Boudiaf, Ph. Soyer, C. Terem, J. Pelage, E. Maissiat, R. Rymer

. CT Evaluation of Small Bowel Obstruction. RadioGraphics 2001; 21:613–624