J Korean Radi이 Soc 1997; 37: 1091 -1096

CT Findings of Enteric Fistula 1

Jae Cheol Hwang, M.D., Hyun Kwon Ha, M.D., Young Cheol 、Veon ， M.D. ， Moon-Gyu Lee, M.D., Pyo-Nyun Kirn, M.D., Yong Ho Auh, M.D.

Enteric fistulae result from gastrointestinal perforations in which communication is established between the site of perforation and another hollow viscus, potential space, or skin surface. Certain types of enteric fistulae are difficult to demonstrate by conven­ tional radiographic methods, and CT is unique in its ability to demonstrate the extent and nature of extraluminal changes. The purpose of this study is to illustrate the CT findings of enteric fistulae occurring in a variety of abdominal and pelvic organs.

Index words : Fistula, gastrointestinal Gastrointestinal tract, CT

Enteric fistulae can develop as a result of a broad CT scanning may help determine the etiology. To as­ spectrum ofinflammatory or neoplastic processes any­ sess the thickness of bowel wall and distinguish ab­ where along the length of the gastrointestinal (GI) scess from bowel loops, optimal bowel opacification tract. As the signs and symptoms are varied and and proper distention is essentiaL and to achieve this, nonspecific, CT may be the initial imaging study several techniques may be employed (1). In suspected performed on patients with fistulae. CT itself may not cases of pelvic fistulae, rectal contrast materials are visualize a fistula, though certain CT findings may routinely administered unless contraindicated by the suggest the use of a barium stud y for diagnosis. In ad­ presence of severe rectal pain and/or perineal disease dition, in patients with known enteric fistulae, CT may To eliminate the possibility of abnormal air in the pel­ disclose other ancillary extraluminal abnormalities or vic organs, bladder catheterization and gynecologic complications, such as abscess formation, peritonitis, examination should be avoided for 24 hours before CT or lymphadenopathy, which barium study alone, examination. In the search for an abscess and in the might not reveal. This report illustrates the CT findings evaluation of thickened bowel wall or mass, contrast of various types of enteric fistulae and correlates them materials are important, but if an enterovesical fistula with those of conventional contrast studies. is suspected, intravenous contrast enhancement should be avoided. Eight-to-ten-millimeter collimation at lO-millimeter Technical Considerations intervals covering the entire abdomen and pelvis is Routine CT examinations of the abdomen often re­ preferred initially ; this can be followed by contiguous sult in inadequate evaluation of enteric fistulae, unless scanning of the region of interest, using thinner special effort is made to enhance their detection. In a sections. For demonstration ofthe fistula tract, delayed certain type of fistula, modifications of CT scanning examination is often helpful. protoc이 can improve the overall diagnostic rate. In patients with biliary-enteric fistula, pre-enhanced Fistulous Communication between the GI Tract 'Department of Diagnostic Radiology, Asan Medical Center, University ofUlsan A variety of fistulae, including gastrocolic, gastro­ C이 l egeo fMedicin e , , , , Received June 13, 1997; Accepted October 9, 1997 enteric enteroenteric enterocolic or colocolic may Address reprint requests to: Jae Cheol Hwang, M.D. , Department ofDiagnostic occur as a complication of benign or malignant disease Radiology Asan Medical Center University of Ulsan Co llege of Medicine of the GI tract; presentation varies depending on the ~ 388.1 Poongnap-dong, Songpa-ku, SeouI138-040, Korea Tel. 82-2-224- 4400 Fax.82-2-476-47 19 cause and type of fistula. Pathognomic symptoms of

- 1091 - Jae Che이 Hwang. et al : CT Findings of Enteric Fistula gastrocolic or duodenocolic fistula are feculent vomi­ the underlying cause of a fistula. Malignant tumors ting or the passage of undigested food in the stool. In that cause fistula are bulky and infiltrating (Fig. 1), and most cases, however, nonspecific symptoms, such as are often associated with metastatic foci in other abdominal pain, malabsorption, diarrhea, and weight intra-abdominal organs. Multiple fistula formation loss are the common features (2). For diagnosis of a fis­ with mesenteric change is often characteristic of tula, traditional barium study of the GI tract is con­ Crohn’s disease (Fig. 2) (1 , 2) sidered to be the method of choice ; since, however, the The presence of these types of fistula can be exact nature and extent of the extraluminal disease diagnosed on CT by outlining the contrast-filled fistu­ process cannot be evaluated, the usefulness ofthis ap­ lous tract, but the diagnosis commonly depends on sec­ proach is limited. CT, on the other hand, can provide ondary signs, such as flow diversion of orallyadmi­ important intraluminal and extraluminal pathologic nstered contrast medium (Fig. 3), severe adhesion, findings as well as clues which can help differentiate thickening of adjacent bowel walL or an extralumi-

A B Fig. 1. Gastro-colic fistula in a patient with transverse colon carcinoma. A. Contrast-enhanced CT shows a large inhomogeneous mass of colon carcinoma in splenic flexure, directly invading the stomach. A fistulous tract fiUed with contrast material is suspected (arrows) B. A barium enema shows an annular type of luminal narrowing involving transverse colon and splenic flexure of colon with contrast-filled stomach due to presence of gastro-colic fistula (arrows) 1

A B Fig. 2. Ileo-ileo-sigmoid fistula in a patient with Crohn’ s disease. A. Contrast-enhanced CT shows irregular thickening of sigmoid colon and ilealloops with matted appearance due to severe adhesion. The sigmoid mesocolon is also diffusely infiltrated. Multiple fistulous tracts are suspected (arrows). B. A barium enema demonstrates multiple fistulous communications (arrows) between ilealloops and sigmoid colon. - 1092 - J Korean Radi이 Soc 1997; 37 : 1091 - 1096

A B Fig. 3. Gastro-colic fistula in a patient with history of subtotal gastrectomy. A. Contrast-enhanced CT shows nice depiction of a short fistulous tract between stomach and transverse colon (arrow). B. CT scan at the level of mid portion of kidneys shows relatively a large amount of oral contrast material in descending colon (D) as compared with that of ascending colon (A).

A B Fig. 4. Pancreatic pseudocyst with fistulous communication to transverse colon A. Contrast-enhanced CT shows a cystic mass (arrows) filled with contrast material and air in the transverse mesocolon due to fistulous communication between mass and transverse colon. The pancreas appears to be normal in size and contour. B. A barium enema confirms nal soft tissue component containing air or contrast with anastomotic leakage, and complications of pan­ medium. For cases in which this diagnosis is suggested creatitis, diverticulitis, inf1 ammatory bowel disease, by CT, a barium study is indicated, with special atten­ trauma, or malignancy. CT may be used not only for tion gi ven to the mapping of the fistula origin, course, the diagnosis of an abscess with a fistulous commu­ or terminus. nication to the GI tract but also to provide guidance for drainage. Although rarely seen, the presence in a CT Fistulous Communication between the image of orally-administered contrast medium within Bowel andAbdominal Abscess an abscess pocket is definite evidence offistulous com­ Gastrointestinal fistulas and intra-abdominal absce­ munication to the GI tract (Fig. 4) (3). Other CT findi­ sses commonly co-occur; some are probably causative ngs suggesting this type of fistulous communica­ in nature, and others are sequelae. The most frequent tion include obviously high air-f1 uid levels within an causes of intra-abdominal abscess with fistulous com­ abscess, or bowel wall thickening at the site of a fistula. munication to the GI tract are recent GI tract surgery In clinically suspected cases, however, the absence of 1093 Jae Ch∞ I Hwang, et al : CT Findings of Enteric Fistula

A B Fig. S. Fistulous communication of the bowel with intraperitoneal abscess resulting from perforated appendicitis. A. Contrast-enhanced CT shows an abscess with irregular and thick wall (arrows), closely attaching to adjacent bowel. There is no evidence of air or contrast collection within abscess cavity. B. Cavitogram through the needle inserted percutaneously 3 days after CT examination shows an abscess cavity (A) with fistulous communication to ileal loop (1)

Fig. 6. A 82-year-old woman with cholecysto-duodenal Fig. 7. A 56-year-old man with cholecysto-duodenal fis­ fistula caused by squamous cell carcinoma of gallbladder tula due to perforated acute cholecystitis. Contrast­ carcinoma. Contrast-enhanced CT shows irregular thick­ enhanced CT shows distended gallbladder with air-f1 uid ening of gallbladder wall (arrows) with air and contrast level (open arrows) in the lumen and discontinuity of the material in the lumen. wall in association with pericholecystic air and f1 uid col­ lection (solid arrows). The interface between gallbladder and duodenum is completely lost with thickened duo­ denal wall

Fig. 8. Recto-vesical fistula in a patient with Crohn’ s dis­ ease. Contrast-enhanced CT shows a small amount of air (arrows) in the bladder as well as irregular thickening of the posterior bladder wall (arrowheads) and rectosigmoid colon with complete loss of interface between these two organs. - 1094 - J Korean Radi이 Soc 1997; 37: 1091 -1096

A B Fig. 9. Recto-vesico-uterine fistula in a patient with cervix cancer. A. Contrast-enhanced CT shows contrast collection in uterine cavity (U) with a fistulous tract (arrows) between bladder (B) and uterine cavity. The tumor diffusely infiltrates the uterus and bladder with complete loss of interface. B. Contrast-enhanced CT scan 2 cm cephalad to (A) shows air collection (arrow) in the uterine cavity due to rectouterine fistula. The interface between uterus and rectum is also lost with focal thickening of the rectal walL

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A B Fig. 10. Rectovesical fistula in a patient with perforated rectal cancer. A. Contrast-enhanced CT shows direct communication (arrow) between bladder and necrotic tumor (arrowheads) in rectovesical pouch. The posterior wall of the bladder is irregularly thickened as well B. Lateral view of the pelvic cavity during intravenous pyelogram shows contrast filling of rectum (R) and necrotic tumor through fistulous communication from the bladder (B). The posterior wall of the bladder is irregularly indented and invaded by tumor (arrowheads) air and f1 uid does not exclude the possibility of an lae, though a fistulous tract can act as a physiological internal fistula (Fig. 5). conduit or permanant alternate route for the excre­ tion of bile. For these reasons, recognition of this type Fistu/ous Communication to the Biliary Tract of fistula is essential for proper management. In 90% of cases, spontaneous communication be­ Characteristic CT findings of biliary-enteric fistula tween the biliary and GI tracts occurs as a complication are the presence of air or orally-administered contrast of the presence of stones in the biliary tract; 10%, medium in the biliary tree (Figs. 6 and 7) (5); CTcan however, are caused by peptic ulcer, tumor, or trauma. demonstrate air in this location with exquisite sensi­ The duodenum is the most common site of biliary-en­ tivity. In addition to spontaneous biliary fistulae, how­ teric fistulae, and most others are found in the stomach ever, previous surgery, patulous sphincter of Oddi, or colon. Ascending cholangitis, GI bleeding, diarrhea, and ascending cholangitis with gas-forming organisms or malabsorption may complicate biliary-enteric fistu- should be considered in differential diagnosis. Other - 1095 - Jae Cheol Hwang. et al : CT Findings of Enteric Fistula ancillary findings include bowe1 wall thickening at the ntrast studies (5); unless a pathologic pathway is di­ site of the fistu1a termination and surrounding in­ rectly demonstrated (5), the key finding is the depic­ f1ammatory change (Fig. 7). Occasionally, CT is a1so tion of air or orally-administered contrast medium in he1pfu1 in eva1uating the primary cause of a biliary-en­ the genitourinary tract (Figs. 8 and 9). Other ancillary teric fistu1a CT findings include an extraluminal mass adjacent to the bowel, foca1 wall thickening of the involved Fistulous Communication to the Genitouri­ organs, and comp1ete 10ss of the intervening fat p1ane naryTract between the GI and genitourinary tract (Fig. 10). Fistu10us communication between the GI and genitourinary tract can deve10p as a result of compli­ References cations arising from diverticulitis, co1orecta1 malig­ nancy, Crohn’s disease, gyneco1ogic malignancy, pre­ 1. Gore RM. Cross-sectional imaging of inf1ammatory bowel dis­ vious pe1vic surgery or irradiation, or trauma. Because ease. Radio/ C/in North Am 1987; 25(1): 11 5-131 of the close proximity of its anatomic 10cation, the ma­ 2. Pichney LS , Fantry GT, Graham SM. Gastrocolic and duo­ denocolic fistula in Crohn disease. J C/i n Gastroentero/ 1992; 15 jority of fistu1ae occur in the pelvic cavity and include (3): 205-211 the enterovesical, rectourethral, enterouterine, and 3. Fukuya T, Hawes DR, Lu CC . CT of abdominal abscess with fis­ enterovagina1 types. In such cases, patients usually tulous communication to the gastrointestinal tract. J Comput present with urinary symptoms which suggest diag­ Assist Tomogr 1991; 15(3) ‘ 445-449 nosis; they are re1ated to diversion of urinary or feca1 4. Harkavy LA, Balthazar EJ , Naidich DP. CT diagnosis of cho­ f1ow, such as fecaluria, pneumaturia, or passing feces lecystod uodenal fistula. Am J Gastroentero/ 1985; 80 ‘ 569-571 5. Kuhlman JE, Fishman EK. CT evaluation of enterovaginal and or urine via the vagina. vesicovaginal fistulas. J Comput Assist Tomogr 1990 ; 14(3) : For eva1uating this type of fistu1a, CT has proven to 390-394 be more sensitive and acccurate than conventiona1 co-

대한밤시선의학호|지 199? ;3?: 1091-1096

장루의 CT 소견 1

l 울산대학교 의과대학 서울중앙병원 진단방사선과학교실

황재철·하현권·원영철·이문규·검표년·오용호

장루 (enteric fistu1a) 는 위장관 천공에 의해 발생하며 천공 부위와 다른 장관， 복강내 공간， 또는 피부와 연결 된 것이다. 어떤 형태의 장루는 종래의 방사선 검사로 증명하기가 어려울 때가 있다. 전산화단층촬영은 장관 밖 의 변화와 침범 부위를 평가하는데 탁월한 검사 방법이다. 이 임상 화보에서 복강과 골반강 장기에 발생한 다양 한 장루에 대한 전산화단층촬영 소견을 기술하고자 한다

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