The Unsuspected Complications of Bacterial Endocarditis Imaged by Gallium-67 Scanning

Shobha P. Desai and David L. Yuille

Nuclear Medicine Department, St. Luke's Medical Center, Milwaukee, @V&sconsin

tivity in the region of the aortic valve which extended into the In this case report, we present a patient with bacterial endocar right atrium (Fig. 1)but was better appreciated on an axial SPECF ditiswho was evaluatedby 67(@imagingfor persistentfever image (Fig. 2). despitetreatmentwith multipleintravenousantibiotics.Afthough cardiac catheterizationconfirmeda densely calcified bicuspid evidence of bactenal endocarditiswas absent wfth @“Gaimag aorticvalve with both stenosis and insufficiencyas well as what ing,the studydemonstratedfindingsthat representcomplica was thoughtto be aveiy largerightsinus ofvalsalva aneurysm.At tions of bacterial endocarditis. The procedure demonstrated surgery, there was evidence of epicarditisand pericarditisand a moderatepencardialuptakeof isotopeandthus pro@4dedthe hugerightsinus of valsalva abscess was foundwhich was eroding first evidence of pehcardi@swhich was later confirmed at sur into the aortic wall. The aortic valve annuluswas debrided, the gery.The studyalsodemonstratedmi@ increasedactivityin abscess cavity was drainedandthe patient's diseased aorticvalve thevicinityoftheaorticrootandnghtattium.A sinusofvalsalva was replacedwith a no. 25 St. Jude's prosthesis (St. JudeMedical abscess, complicatingthe underlyingdiagnosis of bacterialen Inc., St. Paul, MN). The immediatepostoperativeperiodwas docarc@bs,was found and treatedwfthsurgeryand antibiotics.At uneventful, but 2.5 wk after surgery, the patient began to develop autopsy4 wk later,a persistencesinusofvalsalvaabscesswas complex arrhythmias with first degree atrioventricular (AV) block foundwhichextendedintothe rightatrium. and dissociation. One and a half weeks later, she suffered an episode ofventricular tachycardiawhich terminatedinventricular J NucIMed1993;34:955-957 asystole. At autopsy, sections of the heart showed an abscess in the tight atrium which involved both pericardialfat and atrial myocardium,as well as evidence of fibrinouspericarditis.

he early recognition of pericarditis can be difficult, particularly in postoperative patients and in those with DISCUSSION other severe illnesses which may mask the clinical signs The ability of 67Ga to accumulate in inflammatory le and symptoms. The effectivenessof 67Gascanning has sions of bacterial and nonbacterial origin have been known been demonstrated in many inflammatoryand neoplastic for many years (3—6)and its use in cardiomyopathies and lesions (1,2). In recent years, many cases of 67Gauptake by endocarditishas been proposedby many authors (7—10). the heart havebeenreported. O'Connell (11) demonstrated an accumulation of 67Gain four cases of pericarditis, three of them with an effusion. CASE REPORT Multiple factors contribute to the accumulationand re A 62-yr-oldwhite female,who had a heartmurmurknown tentionof 67Gain inflammatorylesions (12). Gallium-67has since 1986and a history ofextensive dental work in late 1989,was a high affinity for both transferrin and lactoferrin and is transferred to our institution in January of 1990 with a diagnosis of boundto circulatingtransferrin after intravenousinjection. acute enterococcus endocarditis and accompanying septicemia. The affinity of 67Ga for lactoferrin explains its accumula An admissionechocardiogramwas performedwhich revealed tion in abscessesbecauseof high lactoferrin levels in neu moderate aortic stenosis with large vegetations on a bicuspid trophils. In addition, bacteria normally produce sidero aorticvalve. The patient remainedfebrilewith daily fever spikes phores, small molecules with a high affinity for iron. despite intravenous administration of multiple antibiotics. A galliumscanwasperformedforlocalizationofanyadditional Gallium will form a complexwith thesesiderophoresin a inflammatory sites approximately 1 wk after admission. The pa manner similar to iron. The gallium-siderophore complex is tient was injectedwith 10 mCi of 67Ga-citrateand whole body then takenupby the bacteriaby a specific iron-siderophore imagingwas performed48 hrpostinjection.SPECT images of the transport mechanism (13,14). These observations explain chest were also obtained at that time. The study demonstrated the finding that neutropenic animalswith abscesseswill moderatelyincreased activity surroundingthe heartin a distribu still accumulate67Ga.Gallium-67is also taken up by cer tion suggesting pencarditis. Also noted was mildly increased ac tam tumors which exhibit specific transferrin receptors on their cell surfaces.The 67Gatransferrin complex is taken ReceivedDec.30,1992;revisionacceptedFeb.25,1993. up intact by thesetumors and is depositedintracellularly. Forcorrespondenceor reprintscon@ ShobhaP. Desai,MD,Resident,Nu dear Methane Dept., St Luke's Med@ Center, 2900 W. Oldahoma Ave., P.O. This latter mechanism of 67Ga uptake has not been dem Box 2901 , Milwaukee, Wi 53201-2901. onstrated in inflammatory lesions. Cardiac uptake may be

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FiGURE2. Gallium-67scan aftera 48-hrdelay. Transverse SPECTimagesofthorax.MOderatelyincreasedactivitysurrounding the heart(thinlongarrows)suggestiveof pericardftis.Also seen is mildlyincreasedactivityinthe regionof aorticvalve,whith extends intonghtatrium(shortthickarrows)indicativeof abscess. FiGURE1. Gallium-67scanaftera48-hrdelay.Fortydegreeleft anteriorobliqueview of thorax.Evidenceof moderatelyincreased activitysurroundingthe heart (thinblackarrows)indicativeof pad ciated with AV block and AV dissociation. Both of these cardsis.There Is also notedfalnt increaseduptake(thickshortar were also present in our patient. rows)in the reg@nof nghtatriumsuggestiveof abscess.Sternum The sensitivity of galliumscans for the diagnosis of bac activity is marked with arrow heads. terial endocarditis has been variable. Wiseman et al. (7) reported the results of 67Gascanning in 11 patients with either focal or diffuse. Table 1 lists a number of conditions subacutebacterialendocarditisandfound abnormaluptake resulting in 67Gauptakeby the heart. intheregionoftheheartin64%ofthecasesscanned72hr Pericarditis has been associatedwith uncomplicated after an injection. In the series presented by Melvin et al. bacterial endocarditis.The exact mechanismcausingthis (25), only two gallium scanswere positive for cardiac up association is unclear but mediation by circulating immune take out of a total of 28 (7%). Neither positive study iden complexes has been mentioned as a possible cause (22). tilled the involved valve. The discrepancy between these Pericarditismay also be seen in patients with a persistent two series may be due to differences in the site of involve bacterial infection (23) which was present in this case. Of ment. In the series presented by Melvin et a!., right-sided more importance is the observation by Arnett et al. (24) endocarditis predominated. The annulus and surrounding that pericarditis is frequently associatedwith the develop myocardiumareknown to have markedlyless involvement ment of a ring abscess in patients with bacterial endocar in tricuspid endocarditis than in left-sided disease and less ditis. In Arnett's series, 14 of 18 (78%) patients with peri carditis in the setting of bacterial endoca.rditishad a ring gallium uptake might be anticipated on this basis. In addi abscess.Furthermore,in 13of 14(93%)patientswith aring tion, early antibiotic therapy has been shown to decrease abscess and pericarditis, the pericarditis was due to in leukocyte migration to infected tissue. In all of the patients volvement of the epicardiumby extensionof the abscess. in Melvin's series, antibiotics were started before gallium Extension of the abscessto involve the septumwas asso scanning was carried out. Our case was similar in that a

TABLE 1 ConditionsResultingfromGallium-67Uptakebythe Heart CommonUncommonRarePericarditis (20)MyOCarditiS(11)Acute myocardialKawasaki disease (15)InflammatoryPostpericard@tomy15cardiomyopathy(15)infarction (16,21)HypersensitivIty angitis

(10)Bacte@alMyocardial(11)syndrome abscess(S)endocarditis (7)Pencardial myocard@neoplasticand/or (16-iS)Sarcoidosisinvolvement (19)

956 TheJournalof NuclearMedicine•Vol.34•No.6 •June1993 definite diagnosis of endocarditis could not be made with 2. Tsan MF, Chen WY, Scheffel U, Wagner HN. Studies on gallium accumu gaffiumin a patientwho hadbeentreatedwith antibiotics. lationin inflammatorylesions:I. Galliumuptakeby humanpolymorphonu clearleukocytes.I NuciMed 1978;19:36—43. The association between a ring abscess and bacterial 3. Ito Y, Okuyama S, Sato K, et al. Gallium.67 tumor scanning and its mech endocarditis has been known for almost 140yr (26)and the anisms studied in rabbits. Radiology 1971;100:357-362. association between pericarditis and bacterial endocarditis 4. HeshikiA,SchatzSL,McKusickKA,etal.Gallium-67scanninginpatients with pulmonaiysarcoidosis.AmI Roentgenol1974;122:744-749. for 120yr (27). The frequency of a ringabscess in bacterial 5. LiuenbergRI, TaketaRM,AlazrakiNP,et al.Gallium-67for localization endocarditis may be as high as 28% (27/95) in patients of septiclesions.Annhit Med 1973;79:403—406. without prosthetic valves, with the vast majorityof cases 6. Higasi T, Nakayama Y, MurataA, et al. Clinical evaluation of 67Ga-citrate scanning. JNucI Med 1972;13:196-201. involving the aortic valve annulus (24). In patients with 7. Wiseman J, Rouleau J, Rigo P, Strauss HW, Pitt B. Gallium-67myocardial bacterial endocarditisinvolving a prostheticvalve, the in imagingforthedetectionofbacterialendocarditis.Radiology1976;120:135— cidence of a ring abscess is much higher (63%) (28). The 138. presenceof an abscessmay significantlyalter the prognosis 8. Spies SM, Meyers SN, Barresi V. Grais IM, DeBoer A. A case of myocar dial abscess evaluated by radionuclide techniques: case report.JNucIMed in thesepatientsby affectingboth the responseto medical 1977;18:1089—1090. managementand the successof surgicalintervention. 9. Krameri,GoldsteinRE,HirshfeldJ, RObertsWC,GoldsteinSE,Johnston The use of 67Ga in pericarditis has been proposed by GS. Myocardial infarct imaging with 67Ga-citrate[Abstracti. I Nuci Med 1973;14:418. several authors, although figures for sensitivity and speci 10. RobinsonJA, O'ConnellJ, HenkinRE, GunnarRM.Gallium-67imagingin ficity havenot beengiven. Galliumscansreportedlyhavea cardiomyopathy. Ann Intern Med 1979;90:198—199. low incidence of positive scans in patientswithout localiz 11. O'ConnellJ, RobinsonJA, HenkinRE, GunnarRM. Gaffiumcitrate scan ningfor noninvasivedetectionofinflammationinpericardialdiseases.AmJ ing signs. Conventional 67Ga citrate imaging of the chest Cardiol 1980;46:879-884. may also be used in identifying patients with intramural 12. Tsan MF. Mechanism of gallium-67 accumulation in inflammatory lesions. cardiac abscesses. In our case, mildly increased activity JNucIMed 1985;26:88-92. was noted in the regionof the aorticrootwhich was seen to 13. Emery 1, Hoffer PB. Siderophore.mediated mechanism of gallium-uptake demonstratedin the microorganismUstilagosaphaerogena.I Nuci Med extend into the right atrium on SPEC!' images. These 1980;21:935—939. observations correlated with subsequent surgical and au 14.EmeryT. Thestorageandtransportofiron.In:SigelH, ed.Metalionsin topsy findings. In the settingof pericarditis, however, dis biologicalsyste,ns,volume 7. New York: MarcelDekker, 1978:77-126. 15.ShahPJ,ShreeveWW.Uptakeof67Gainthecardiacregioninhypersen tinguishingpericardialfrom aortic root and right atrialac sitivityangiitis.ClinNuciMed 1981;6:547-549. tivity is difficult on planar images but is somewhat easier on 16. TailleferR, LemieuxR-J,PicardD, et al.Gallium-67imaginginpericarditis SPEC).' images, particularly if the association between ring secondaryto tuberculosisandhistoplasmosis.ClinNuciMed 1981;6:413- abscesses and pericarditis in patients with bacterial endo 415. 17. Yeh SDJ, Benua RS. Gallium-67 citrate accumulation in the heart with carditis is kept in mind. tumorinvolvement.ClinNuciMed 1978;3:103—105. 18. Simpson AJ. Malignant pericardial effusion diagnosed by combined 67Ga SUMMARY citrate and @Tc-pertechnetatescintigraphy. Clin Nuci Med 1978;3:445- 446. We present unusual findings on gallium scanning in a 19. Tajima T, Naito T, Dohi Y, et al. Gallium-67 and Thallium-201 imaging in patient with bacterial endocarditis complicated by pericar sarcoidosis involving the myocardium. Clin NuciMed 1981;6:120-121. 20. Sty JR. Chusid Mi, Dorrington A. Ga-67 imaging: Kawasaki disease. Clin ditis and an aortic root abscess extending into the right NuciMed 1981;6:112—113. atrium. Gallium-67 scanning demonstrated pericarditis and 21. Schor PA, Massie BM, Botvinick EH, et al. Gallium-67 uptake in silent abscess of the aortic root in the absence of clinical findings myocardialinfarction:a case report. Radio1ORJ@1978;129:117-118. 22. Cecil textbook ofmedicine, 19th edition. Wyngaarden JB, Smith LH, Ben which was subsequently proven at surgery and autopsy. nett JC, eds. Philadelphia: WB Saunders Company; 1992:1641. 23. Cecil texthook ofmedicine, 17th Edition. Wyngaarden JB, Smith UI, eds. ACKNOWLEDGMENTS Philadelphia:WBSaundersCompany;1985:340. 24. Ameft EN, RobertsWC. Valve ring abscess in active infective endocarditis. The authors thank Dr. Spiegelhoff for reviewing the manu Circulation 1976;54:140-145. script; Dr. Schmitt for reviewing autopsy findingswith us; and 25. MelvinET, BergerM, LutzkerLG, et al.Noninvasivemethodsfor detec tion of valve vegetations in infective endocarditis. Am I Cardiol 1981;47: Ms. Jean Lemanski and Ms. Pat Pfefferfor preparingthe manu 271—278. script. 26. Rokitansky C. Lehthuch derpathologicchen anatomie, volume II. Wein: WilhelmBraumuller;1856. REFERENCES 27. Ponfick. Ueber embolische aneurysmen, nebst bemerkungen uber das acute herzaneuiysma (herzgeschwur). VirchowArch PatholAnat 1873;58:528. 1. LavenderJP, Lowe J, BarkerJR, BurnJI, ChaudhriMA. Gallium-67citrate 28. O'Brien K, Barnes D, Martin R, Rae JR. Gallium-SPECF in the detection scanning in neoplastic and inflammatory lesions. BrJ Radio! 1971;44:361— of prostheticvalveendocarditisandaorticringabscess.I NuciMed 1991; 366. 32:1791—1793.

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