Finding nemo: imaging findings, pitfalls, and complications of ingested fish bones in the alimentary canal

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1 Emerg Rdiol (2013) 20: DOI /s PICTORIAL ESSAY Finding nemo: imging findings, pitflls, nd complictions of ingested fish ones in the limentry cnl Chrlene Jin Yee Liew & Angeline Choo Choo Poh & Tiong Yong Tn Received: 11 Octoer 2012 / Accepted: 17 Decemer 2012 / Pulished online: 27 Decemer 2012 # Am Soc Emergency Rdiol 2012 Astrct In Asin cuisine, fish is often prepred whole with the ones. Accidentl fish one (FB) ingestion is not n infrequently encountered condition in the emergency deprtment. An impcted FB in the limentry cnl cn led to potentilly life-thretening complictions. For impcted FBs tht cnnot e visulized cliniclly, rdiogrphs nd multidetector computed tomogrphy re helpful in loclizing the FB, evluting for complictions, nd plnning tretment. In this pictoril essy, we illustrte the spectrum of rdiologicl findings of impcted FBs, common imging pitflls, nd complictions. Finlly, we highlight the imging findings tht re importnt to the clinicin in plnning tretment. Keywords Impcted fish one. Complictions. Alimentry cnl. Gstrointestinl trct. Lterl neck rdiogrph. Multi-detector computed tomogrphy Introduction Fish is n importnt nd populr food source glolly. In mny Asin cuisines, fish is often prepred whole, without removing the ones. This results in high incidence of ccidentl fish one (FB) ingestion [1]. An ingested FB cn ecome impcted nywhere long the limentry cnl, leding to potentilly life-thretening complictions if not detected erly. Clinicl exmintion is usully sufficient to identify impcted FBs ove the level of the cricophryngeus muscle. However, the physicl limittions of fier optic scope length nd the nturl ntomicl stte of collpsed nd opposed esophgel wlls preclude visul exmintion elow the level of the cricophryngeus. Removl of n impcted FB in the cervicl esophgus involves exmintion under generl nesthesi with rigid endoscopy, which crries smll risk of esophgel perfortion [2]. Hence, it is importnt tht n ccurte dignosis is mde efore sujecting the ptient to the risks of oth endoscopy nd generl nesthesi. Rdiogrphy nd multidetector computed tomogrphy (MDCT) hve een used to loclize impcted FB, evlute complictions, nd pln tretment. A thorough understnding of the imging ppernce of impcted FBs, ssocited complictions, s well s ntomicl vrints nd imging rtifcts tht cn mimic FBs, is prerequisite to correct dignosis nd pproprite tretment. C. J. Y. Liew (*) : A. C. C. Poh : T. Y. Tn Deprtment of Dignostic Rdiology, Chngi Generl Hospitl, 2 Simei Street 3, Singpore, Singpore e-mil: chrlenejyliew@gmil.com Role of rdiogrphy In our institution, the lterl neck rdiogrph is often the first imging study if the ptient complins of throt pin

2 312 Emerg Rdiol (2013) 20: Fig. 1 Lterl neck rdiogrph demonstrtes preverterl soft tissue nterior to C6 oscured y the shoulders (sterisk). Repet X-ry with the shoulders depressed revels Y- shped FB t the level of C6 (rrow) * fter FB ingestion nd clinicl exmintion is negtive or equivocl. Although plin rdiogrphs re chep nd cn e performed expeditiously, the sensitivity of lterl neck rdiogrphs in the detection of FBs hs een reported to e s low s 25.3 % [3] nd their routine use is controversil. Optiml rdiogrphic technique with dequte depression of the shoulders nd low pek kilovoltge nd millimpere settings re importnt to void oscuring impcted FBs (Fig. 1). For suspected complictions of ingested FB in the thorcic esophgus such s perfortion, chest rdiogrphs my occsionlly demonstrte pneumomedistinum. The positivity rte for plin rdiogrphy in the detection of pneumoperitoneum hs een reported to e s high s 89.2 % [4]. However, pneumoperitoneum is lmost never seen in foreign ody perfortion of the gstrointestinl trct s the progressive erosion of the one through the intestinl wll llows the perfortion to ecome seled off, limiting the pssge of lrge Fig. 2 Lterl neck rdiogrph in two different ptients with impcted FB. In fint, verticlly orientted FB in the soft tissue nterior to C7 (rrow) is more esily seen thn horizontlly impcted FB in the soft tissue nterior to C6 t the level of the cricophryngeus muscle (rrow)

3 Emerg Rdiol (2013) 20: Fctors tht ffect visuliztion of FBs on the lterl neck rdiogrph Fctors tht ffect the visuliztion of FBs on the lterl neck rdiogrph include loction of impction, orienttion, nd density of the FB [6]. c d e Loction of impction An FB my e impcted t ny point long the upper erodigestive trct, ut review res should include the se of the tongue, pltine tonsils, piriform sinus, vllecul, nd the level of nd elow the cricophryngeus muscle. Surrounding soft tissue density is most prolemtic t the level of the cricophryngeus muscle, which my hinder the visuliztion of n impcted FB. Orienttion of the FB Fig. 3 Schemtic overly of lterl neck rdiogrph showing the norml structures tht my simulte FBs. Styloid process nd ossifiction of the stylohyoid ligment (dshed line). Thyrohyoid ligment (dshed line). c Arytenoid crtilge (rrow). d Thyroid crtilge. e Cricoid crtilge (posterior lmin) mounts of free ir into the peritonel cvity [5]. Erect chest nd dominl X-rys, therefore, re of limited vlue. With respect to the longitudinl xis of the FB, verticlly impcted FB which is orthogonl to the film is esier to detect compred to one which is horizontlly impcted (Fig. 2). Density of the FB The ones of different species of fish differ in opticl density hence ffecting visiility on rdiogrphs [7]. A study of fish species consumed in the USA found tht ones from the Fig. 4 Lterl neck rdiogrph demonstrtes prtil ossifiction of the superior cornu of the thyroid crtilge (rrow) nd the lterl thyrohyoid ligment (rrow) simulting impcted FB

4 314 Emerg Rdiol (2013) 20: ctfish nd lrge mouth ss re more rdiodense compred to species such s red snpper nd trout [6]. Imging pitflls of the lterl neck rdiogrph On the lterl neck rdiogrph, it cn e difficult to differentite n impcted FB from norml ntomicl structures nd vrints. Ossifiction of the lryngel crtilge nd ligments tkes plce progressively with ge nd my pose dignostic prolems. Detiled discussion of the pttern of ossifiction is eyond the scope of this review, ut it is useful to note tht ossifiction egins in lte dolescence, the thyroid crtilge ossifies infero-superiorly nd then postero-nteriorly, nd the superior lmin of the cricoid crtilge ossifies efore the rest of the crtilge [8]. Common ntomicl structures tht my mimic n ingested FB in the neck include the prtil ossifiction of the superior cornu of the thyroid crtilge, posterior lmin of the cricoid crtilge, rytenoid crtilge, the stylohyoid nd thyrohyoid ligments, nd the styloid processes (Figs. 3, 4, 5, 6, nd 7). Differentition of these structures from impcted FBs cn e mde sed on the typicl ntomicl loction, pired nture, nd lck of secondry findings such s preverterl soft tissue swelling or cervicl emphysem. Other norml vrints such s vsculr clcifictions cn lso mimic impcted FBs (Fig. 8). In the event tht confident dignosis cnnot e mde on rdiogrphs, MDCT redily differentites truly impcted FBs from norml ntomicl structures. Fig. 6 Lterl neck rdiogrph shows ossifiction of single rytenoid crtilge (rrow). Note the rel impcted FB t the level of C6 (dshed rrow) Multidetector CT The sensitivity of MDCT in detecting n impcted FB is reported to rnge from 90 to 100 % [6, 9, 10] with specificity of 93.7 to 100 % [11, 12]; hence, MDCT is Fig. 5 Lterl neck rdiogrph demonstrtes ossifiction of the cricoid crtilge. Liner ossifiction of the posterior lmin of the cricoid crtilge thought to e n FB (rrow). Sgittl reconstructed MDCT imge confirming ossifiction of the posterior lmin of the cricoid crtilge (rrow)

5 Emerg Rdiol (2013) 20: Fig. 7 Lterl neck rdiogrph shows single styloid process (rrow) nd ossified stylohyoid ligment mimicking FB (rrow) Fig. 8 Lterl neck rdiogrph demonstrtes liner opcity suspicious for n impcted FB seen in the preverterl soft tissue t T1 (rrow). Unenhnced xil CT demonstrtes clcified verterl rtery mimicking n FB (rrow) Fig. 9 Coronl MIP CT imge demonstrtes Y-shped FB (rrow) tht hd perforted the left nterolterl wll of the esophgus. A 2-cm Y-shped FB ws removed with rigid endoscopy

6 316 Emerg Rdiol (2013) 20: Tle 1 MDCT protocols for evluting impcted FB Body region Scn rnge Tue voltge/current Contrst Slice thickness Neck Thorx Adomen nd pelvis Floor of mxillry sinus to inferior order of T1 Suprclviculr region to crin if performed concurrently with CT neck, otherwise suprclviculr region to diphrgm Diphrgm to symphysis puis 120 kvp/utomted Noncontrst. IV contrst if compliction seen: volume 50 ml, rte 1.5 ml/s. Dilute orl contrst (Iohexol, 50 ml, diluted 1:2) if there is dout regrding intrluminl component of FB 120 kvp/utomted Noncontrst. IV contrst if compliction seen: volume 50 ml, rte 1.5 ml/s 0.5 mm cquisition with reconstruction to 3 mm slices in multiple plnes without overlp 1.0 mm cquisition with reconstruction to 3 mm slices in multiple plnes t 0.8 mm intervls 120 kvp/utomted IV contrst, volume 70 ml, rte 1.5 ml/s 1.0 mm cquisition with reconstruction to 3 mm slices in multiple plnes t 0.8 mm intervls significntly superior in detecting FB compred to plin rdiogrphy [10]. On MDCT, FBs typiclly present s liner, Y- or irregulrly shped rdiodense lesions rnging from 1 to 3 cm within the limentry cnl with vrile orienttion. Multiplnr reformtions llow for ccurte depiction of the loction, size, nd configurtion of the impcted FB (Fig. 9). MDCT cn lso demonstrte complictions in djcent structures. The region to e scnned nd the decision to give IV contrst need to e tilored to where the FB is cliniclly suspected to e impcted or is cusing complictions. In generl, for FBs tht re impcted in the upper erodigestive trct, noncontrst scns re performed, unless complictions such s scess or vsculr injury re immedite concerns. Tle 1 summrizes the MDCT protocols we use in our hospitl for evluting suspected impcted FB. Imging pitflls of MDCT Although CT is very sensitive nd specific for evluting impcted FBs nd their complictions, some imging pitflls exist. Tonsilloliths Tonsilloliths re focl clcifictions seen in the crypts of lymphoid tissue in the tonsils. They commonly pper s Fig. 10 Axil unenhnced CT imges show rounded densities in the right tonsil comptile with tonsilloliths (rrows) Fig. 11 Axil unenhnced CT imge from ptient with history of FB ingestion demonstrtes n ill-defined liner density (rrow) t the level of the piriform foss secondry to swllowing motion rtifct, mimicking n FB

7 Emerg Rdiol (2013) 20: usully more morphous compred to true FBs which hve shrp mrgins. Artifcts from rdiodense mteril, e.g., rium or silver nitrte [13] my lso mimic FBs. In this instnce, ccurte clinicl informtion is importnt to void this pitfll (Fig. 12). Complictions of impcted FBs Fig. 12 A 25-yer-old mn with history of throt pin fter eting fish. Axil imge of the neck shows liner density (stright rrows) in the left se of tongue. The region is lso prtilly oscured y strek rtifcts from dentl rces (dshed rrow). The density ws thought to represent n FB, ut none ws found on explortion. It ws lter reveled tht the ptient hd recent history of silver nitrte ppliction to leeding tonsillr ulcer smll, well-defined, rounded densities, s opposed to FBs, which re usully liner or irregulrly shped (Fig. 10). Imging rtifcts Swllowing motion rtifcts my pper s streky densities nd mimic impcted FBs (Fig. 11). Motion rtifcts re Perfortion of the limentry trct y n impcted FB cn led to numer of complictions, depending on the loction. A perforted FB my migrte into djcent structures; dmge vitl vessels; cuse cervicl emphysem, pneumomedistinum, nd fistul; nd serve s nidus for infection resulting in medistinitis, peritonitis, nd scess formtion. Cervicl emphysem nd pneumomedistinum The most common site of FB impction nd susequent perfortion of the esophgus is t the nturl nrrowing t the level of the cricophryngeus muscle [14]. The presence of cervicl emphysem nd pneumomedistinum ssocited with rdiodense foreign ody in the esophgus should rise the suspicion of FB perfortion (Fig. 13). Emedment in the esophgel wll A longitudinlly orientted FB my ecome completely emedded in the esophgel wll (Fig. 14) requiring esophgotomy. Fig. 13 Lterl neck X-ry shows pneumomedistinum (rrows). There is fint liner density in the preverterl soft tissues t the level of C6 (dshed rrow). Axil unenhnced CT imges () demonstrte horizontlly impcted FB (dshed rrow), which hs perforted the esophgus. Extensive cervicl emphysem is present (rrows)

8 318 Emerg Rdiol (2013) 20: Fig. 14 Coronl () nd xil () unenhnced CT imges demonstrte liner FB completely emedded in the wll of the esophgus (rrow). The FB could not e removed with rigid endoscopy nd esophgotomy hd to e performed Retrophryngel scess nd medistinitis The most common compliction from perforted FB in the neck is retrophryngel scess [14]. Fluid or rim-enhncing collections in the retrophryngel or other deep spces in the neck should rise the suspicion of perfortion (Fig. 15). As the retrophryngel spce extends inferiorly to the posterior medistinum, this provides conduit for infection to spred into the chest, resulting in medistinitis (Fig. 16) [15, 16]. Migrtion of FBs A perforted FB my migrte into the surrounding structures such s glnds, muscles, nd orgns often resulting in scess formtion (Figs. 17, 18, nd 19). Rrely, n FB my migrte out of the cervicl esophgus nd end up extruding through the skin [17]. Vsculr complictions Migrted FBs cn dmge djcent lood vessels. In the esophgus, there hve een severl cse reports of FB perforting nd cusing ortoesophgel fistul (AEF), dreded compliction with high mortlity nd moridity. Although AEF is rre, foreign ody perfortion is the second leding cuse of AEF fter thorcic ortic neurysms [18]. MDCT is the imging modlity of choice nd my show findings such s perineurysml hemtom, Fig. 15 Axil unenhnced CT imges (, ) show liner FB tht hs perforted the posterior wll of the phrynx (dshed rrow) t the level of the hyoid one. This hs resulted in smll retrophryngel collection (rrows)

9 Emerg Rdiol (2013) 20: such s the ileocecl region nd rectosigmoid junction (Fig. 21) [20]. This my present cutely or months fter initil presenttion. Notoriously, FB perfortions hve wide spectrum of clinicl mnifesttions, including dominl pin, sepsis from scess formtion, hemorrhge, owel ostruction, nd colic. As such, FB s cuse for perfortion should e ctively sought if other common cuses of perfortion such s ulcer, diverticulitis, or tumor re not evident, especilly in the scenrio of smll owel perfortion [21 23]. Imging findings of perfortion in the lower gstrointestinl trct on MDCT include scess, free gs, phlegmon, owel stricture, ostruction, nd fistul (Figs. 22 nd 23). Creful evlution with one window setting is required to void missing the offending FB. Wht the clinicin needs to know * * Fig. 16 Axil unenhnced CT demonstrtes horizontlly impcted FB in the esophgus (rrow). Post IV contrst enhnced CT imge lower in the thorx demonstrtes posterior medistinl fluid (rrow) nd gs (dshed rrows) nd ilterl pleurl effusions (sterisk) comptile with medistinitis pseudoneurysm, contrst gent extrvstion into the medistinum or esophgus, periortic or intrluminl gs, nd focl murl thickening (Fig. 20) [19]. Perfortion nd scess formtion in the gstrointestinl trct In the gstrointestinl trct, FBs hve higher tendency to lodge nd penetrte owel in segments of cute ngultion, Loction The level t which the FB is impcted ccording to the cervicl nd thorcic vertere should e indicted if the FB is impcted in the esophgus. FBs tht re impcted in the erodigestive trct down to the level of the ortic rch my e removed y the otorhinolryngologist with rigid endoscopy under generl nesthesi. FBs tht re impcted t the lower levels of the esophgus my require the ssistnce of generl surgeon or gstroenterologist with flexile endoscopy. Shpe nd orienttion A verticlly or linerly orientted FB is esier to remove thn horizontlly impcted or irregulrly shped FB. Fig. 17 Axil post IV contrst enhnced CT imge showing liner FB (rrow) prtilly emedded in the left sumndiulr glnd. Sgittl olique reconstruction showing the emedded FB (rrow) nd n inflmmtory sumndiulr lymph node (dshed rrow). The ptient hd history of FB piercing the floor of the mouth

10 320 Emerg Rdiol (2013) 20: Fig. 18 Lterl neck rdiogrph demonstrtes smll liner FB in the expected loction of the piriform sinus (rrow). Axil unenhnced CT imge demonstrtes liner fish one (rrow) tht hs migrted out of the piriform sinus nd hs perforted the thyrohyoid memrne. There is swelling nd inflmmtion of the djcent strp muscle. Findings were confirmed t surgery Intrluminl component It is importnt to comment if prt of the FB is still endoluminl when impcted in the esophgus. In the sence of other complictions, s long s prt of the FB is endoluminl, clinicins will generlly ttempt to remove the FB endoscopiclly. If there is difficulty determining the intrluminl component of n FB ecuse of collpsed esophgus, dministrtion of dilute orl contrst followed y n immedite CT scn of the neck my e helpful (Fig. 24). Intrluminl diluted orl contrst ppers s dense mteril djcent to the FB, outlining the esophgel lumen. If the FB is extrluminl, it will e seprted from the orl contrst y the esophgel wll. Complictions The clinicin should e lerted if n FB hs migrted nd is locted close to vitl structure, e.g., crotid * Fig. 19 Unenhnced coronl CT domen in ptient who ws suspected of hving ureteric colic. A 3-cm curviliner FB (rrow) hs perforted the gstric pylorus nd migrted into the liver resulting in liver scess (sterisk) Fig. 20 A 58-yer-old mn with history of FB ingestion 5 dys prior to dmission, presenting with hemtemesis nd sepsis. Axil CT ortogrm of the thorx shows contrst-filled fistul etween the proximl descending ort nd the esophgus (stright rrow). An djcent medistinl collection contining gs is comptile with medistinitis (dshed rrow). The ptient developed complictions of disseminted septicemi nd died shortly fter

11 Emerg Rdiol (2013) 20: rteries. FB perfortion complicted y hollow viscus perfortion, peritonitis, scess, nd fistul formtion should e descried. Conclusion Rdiogrphs nd MDCT ply role in the dignosis nd mngement of ingested FBs impcted in the limentry trct. This is prticulrly true for FBs lodged elow the level of the cricophryngeus, which cnnot e directly visulized without recourse to rigid endoscopy nd its inherent surgicl risks. Although rdiogrphs re chep, redily ville imging modlity for evluting FBs impcted in the neck, MDCT hs superior sensitivity nd specificity, with the dded ility to demonstrte ssocited complictions. It is therefore essentil to recognize the fetures, imging pitflls, nd complictions of impcted FBs to rrive t timely nd ccurte dignosis. Fig. 21 FB perfortion of the terminl ileum. Coronl contrstenhnced CT () shows rdiodense FB perforting the terminl ileum (rrow) without scess formtion. Findings were confirmed t surgery * Fig. 22 Coronl contrst-enhnced CT. There is n ill-defined intrdominl scess (sterisk). A smll liner density suspicious for n FB is demonstrted (rrow). At surgery, the sigmoid colon ws perforted nd the FB ws not visile, ut ws lter found during exmintion of the surgicl specimen Fig. 23 Coronl () nd xil () contrst-enhnced imges from CT colonogrm performed to evlute suspected diverticulr leeding show horizontlly orientted FB within the lumen of the descending colon (rrow) cusing seled perfortion complicted y stricture formtion

12 322 Emerg Rdiol (2013) 20: Fig. 24 Axil imges pre () nd post () ingestion of orl contrst (Iohexol 350) demonstrtes the intrluminl loction of n FB (rrow). In the collpsed stte of the esophgus in, it is difficult to determine if the FB is intrluminl or extrluminl. Contrst (dshed rrow) is seen djcent nd medil to the outline of the FB fter orl contrst is ingested, depicted s morphous mteril which is less dense thn one, demonstrting tht the FB is intrluminl Conflict of interest The uthors declre tht they hve no conflict of interest. References 1. Nndi P, Ong GB (1978) Foreign ody in the esophgus: review of 2394 cses. Br J Surg 65: Tekinş C, Erol M (2007) Video-medistinoscopy: for extrcting upper esophgel foreign odies. Ann Thorc Surg 83: Evns RM, Ahuj A, Rhys Willims S, Vn Hsselt CA (1992) The lterl neck rdiogrph in suspected impcted FBs does it hve role? Clin Rdiol 46: Bnsl J, Jenw RK, Ro J, Knkri J, Agrwl NN (2012) Effectiveness of plin rdiogrphy in dignosing hollow viscus perfortion: study of 1,723 ptients of perfortion peritonitis. Emerg Rdiol 19: Coulier B, Tncredi MH, Rmoux A (2004) Spirl CT nd multidetector-row CT dignosis of perfortion of the smll intestine cused y ingested foreign odies. Eur Rdiol 14: Lue AJ, Fng WD, Mnolidis S (2000) Use of plin rdiogrphy nd computed tomogrphy to identify FB foreign odies. Otolryngol Hed Neck Surg 123: Ell S, Sprigg A (1991) The rdio-opcity of fishones species vrition. Clin Rdiol 44: Htely W, Evison G, Smuel E (1965) The Pttern of ossifiction in the lryngel crtilges: rdiologicl study. Br J Rdiol 38: Wtne K, Kikuchi T, Ktori Y, Fujiwr H, Sugit R, Tksk T, Hshimoto S (1998) The usefulness of computed tomogrphy in the dignosis of impcted FBs in the esophgus. J Lryngol Otol 112: Plme CE, Lowinger D, Peterson AJ (1999) FBs t the cricophryngeus: comprison of plin-film rdiology nd computed tomogrphy. Lryngoscope 109: Akzw Y, Wtne S, Noukiyo S, Iwtke H, Seki Y, Umehr T, Tsutsumi K, Koizuk I (2004) The mngement of possile fishone ingestion. Auris Nsus Lrynx 31: Elishr R, Dno I, Dngoor E, Brvermn I, Sichel J-Y (1999) Computed tomogrphy dignosis of esophgel one impction: prospective study. Ann Otol Rhinol Lryngol 108: Hely C, Cnney M, Murphy A, Regn P (2007) Silver nitrte msquerding s rdiopque foreign ody. Emerg Rdiol 14: Singh B, Knto M, Hr-El G, Lucente FE (1997) Complictions ssocited with 327 foreign odies of the phrynx, lrynx, nd esophgus. Ann Otol Rhinol Lryngol 106: Chong VFH, Fn YF (2000) Rdiology of the retrophryngel spce. Clin Rdiol 55: Mcrí P, Jiménez MF, Novo N, Vrel GA (2003) Descriptive of series of ptients dignosed with cute medistinitis. Arch Bronconeumol 39: Png KP, Png YT (2002) A rre cse of foreign ody migrtion from the upper digestive trct to the sucutneous neck. Er Nose Throt J 81: Hollnder JE, Quick G (1991) Aortoesophgel fistul: comprehensive review of the literture. Am J Med 91: Pickhrdt PJ, Bhll S, Blfe DM (2002) Acquired gstrointestinl fistuls: clssifiction, etiologies, nd imging evlution. Rdiology 224: Mdron AP, Hernndez JA, Prts MC, Riquelme JR, Pricio PP (2000) Intestinl perfortion y foreign odies. Eur J Surg 166: Goh BK, Tn YM, Lin SE, Chow PK, Cheh FK, Ooi LL, Wong WK (2006) CT in the preopertive dignosis of fish one perfortion of the gstrointestinl trct. AJR Am J Roentgenol 187: Zissin R, Osdchy A, Gyer G (2009) Adominl CT findings in smll owel perfortion. Br J Rdiol 82: Hines J, Rosenlt J, Duncn DR, Friedmn B, Ktz DS (2012) Perfortion of the mesenteric smll owel: etiologies nd CT findings. Emerg Rdiol Dec 5. doi: /s