Thallium-201 chloride scintigraphy in soft tissue tumors

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1 136 ORIGINAL Thllium-201 chloride scintigrphy in soft tissue tumors Hideki Otsuk, Kori Terzw, Nomi Morit, Yoichi Otomi, Shoichiro Tko, Seiji Iwmoto, Kyosuke Oski, Msfumi Hrd, nd Hiromu Nishitni Deprtment of Rdiology, Institute of Helth Biosciences, the University of Tokushim Grdute School, Tokushim, Jpn Astrct : Ojective We report the findings of Thllium-201 chloride ( 201 TlCl) scintigrphy nd consider how to use this technique to evlute the chrcter of soft tissue lesions. Ptients nd Methods We enrolled 91 consecutive ptients (45 mles nd 46 femles, ge rnge 8-91-yers-old). Nineteen ptients were mlignnt nd 72 were enign. Ptients were scnned 15 minutes (erly phse) nd 3 hours (delyed phse) fter 201 TlCl injection. More intense uptke in the lesion compred to the norml side ws considered s high, the sme degree of uptke ws considered iso, nd decresed uptke ws low. The retention index (RI) ws clculted in 9 ptients in the mlignnt group nd in 16 ptients in the enign group. Results In mlignnt tumors, 15 of 19 ptients showed high uptke in oth the erly nd delyed phses. One mlignnt firous histiocytom ptient ws high only in the delyed phse nd 1 liposrcom ptient ws high only in the erly phse. Two liposrcom ptients showed n iso uptke in oth phses. One of these ptients ws pthologiclly dignosed s myxoid type. In enign lesions, no lipom showed incresed uptke. All neurogenic tumors except for 2 demonstrted high uptke. All 3 gnglions of the lower extremities showed iso uptke. Most inflmmtory diseses showed incresed uptke. Cliniclly-considered enign ptients consisted of tumorous lesions or inflmmtory disese. Only 2 ptients were considered low, nd these were dignosed s intrmusculr hemtom nd cyst. RI ws vrile in oth mlignnt nd enign lesions nd no sttisticlly significnt difference ws seen etween mlignnt nd enign lesions y t- test (p=0.72). Conclusions Ahigh 201 TlCl uptke lesion is more frequently seen in mlignnt tumors, ut regrdless of whether the tumor is enign or mlignnt, ccording to the histopthologicl vriety, the 201 TlCl uptke pttern cn not e the only indictor to differentite mlignnt from enign tumors. We ultimtely need to evlute the nture of tumors y comintion of severl imging techniques. J. Med. Invest. 56 : , August, 2009 Keywords : 201 TlCl scintigrphy, soft tissue tumors, retention index, mlignnt, enign INTRODUCTION Thllium-201 chloride ( 201 TlCl) scintigrphy is conventionl nucler medicine technique to evlute Received for puliction Mrch 13, 2009 ; ccepted April 18, Address correspondence nd reprint requests to Hideki Otsuk, Deprtment of Rdiology, Institute of Helth Biosciences, the University of Tokushim Grdute School, Kurmoto - cho, Tokushim , Jpn nd Fx : the nture of tumors. Some studies hve reported the utility of 201 TlCl scintigrphy in the differentition of mlignnt from enign lesions in vrious orgns, including soft tissue tumors (1-4). Mlignnt tumors typiclly demonstrte intense uptke, wheres enign lesions show less uptke. However, the differentition etween mlignnt nd enign soft tissue tumors y the degree of 201 TlCl uptke is sometimes difficult due to the histologicl vriility. 201 TlCl uptke reflects not only mlignnt chrcter ut The Journl of Medicl Investigtion Vol

2 The Journl of Medicl Investigtion Vol. 56 August other fctors such s vsculrity, cell densities or tissue viility regrdless of whether the tumor is enign or mlignnt. We report here the findings of 201 TlCl scintigrphy nd consider how to use this technique to evlute the chrcter of soft tissue lesions. PATIENTS AND METHODS We enrolled 91 consecutive ptients who were exmined for 201 TlCl scintigrphy (45 mles nd 46 femles, ge rnge 8-91-yers-old) in this study. Nineteen ptients were mlignnt nd 72 were enign. All 19 ptients with mlignnt lesions were pthologiclly proven ; 46 of 72 ptients with enign lesions were pthologiclly proven, nd the other 26 ptients were cliniclly dignosed s enign with t lest 6 months of follow up with physicl exmintions nd mgnetic resonnce imging. Ptients hd 111 MBq of 201 TlCl, nd were scnned 15 minutes (erly phse) nd 3 hours (delyed phse) fter the injection. In the erly phse, whole ody imges nd spot scn of the lesion were otined nd spot scn ws performed in the delyed phse. For visul nlysis, more intense uptke compred to the norml side ws considered s high, the sme degree (could not e identified s tumor) of uptke ws considered iso, nd decresed uptke ws low. The retention index (RI) ws clculted in 9 ptients in the mlignnt group nd in 16 ptients in the enign group s follows : RI=(DR-ER)/ER 100 (%). ER (erly rtio) is the rtio of lesion count to contrlterl soft tissue count in the erly phse nd DR (delyed rtio) is the rtio of lesion count to contrlterl soft tissue count in the delyed phse. RESULTS A summry of the ptients is shown in Tles 1 nd 2. In mlignnt tumors, 15 of 19 ptients showed high uptke in oth the erly nd delyed phses (Figure 1). One mlignnt firous histiocytom ptient ws high only in the delyed phse nd 1 liposrcom ptient ws high only in the erly phse. Two liposrcom ptients showed n iso uptke in oth phses. One of these ptients ws pthologiclly Tle 1 A summry of the ptients nd the lesions.

3 138 H. Otsuk, et l. Thllium-201 chloride scintigrphy in soft tissue tumors Tle 2 Uptke pttern of 201 TlCl scintigrphy. Ptients were scnned 15 minutes (erly phse) nd 3 hours (delyed phse) fter 201 TlCl injection. More intense uptke in the lesion compred to the norml side ws considered s high, the sme degree of uptke ws considered iso, nd decresed uptke ws low. d c e Figure 1 Mlignnt peripherl nerve sheth tumor (MPNST) in the left femur of ptient with neurofiromtosis type I. : erly phse imge of 201 TlCl scintigrphy, : delyed phse imge of 201 TlCl scintigrphy. MPNST showed high uptke in oth erly nd delyed phse. c : FIESTA (fst imging Employing Stedy- stte Acquisition) imge of MRI of coronl view. This tumor demonstrted the mixed intensity, seprted y septum, mesured in size of cm. Another neurogenic tumor is locted in the cudl side, which cnnot e detected y 201 TlClscintigrphy.d:AxilT1-weightedSEMRimge with ft suppression. Prts of the tumor showed high intensity, while others showed low intensity compred with the muscle. No ft component ws evident in the tumor. e : Axil gdolinium-enhnced T1-weighted SE MR imge with ft suppression showed strongly enhncement. dignosed s myxoid type (Figure 2) ; while the other hd fluoro-deoxy-glucose positron emission computed tomogrphy/computed tomogrphy (FDG-PET/CT) for follow up of uterine cervicl cncer nd ws incidentlly noticed to hve incresed nodulr uptke in her leg. The tumor showed iso 201 TlCl uptke nd ws considered enign t the time, ut in the follow up period, mlignnt component ws suspected nd it ws surgiclly resected 1.5 yers fter 201 TlCl scintigrphy, nd it ws confirmed s liposrcom pthologiclly. In enign lesions, no lipom showed high uptke (Figure 3). All neurogenic tumors except for 2 demonstrted high uptke (Figure 4). All 3 gnglions of the

4 The Journl of Medicl Investigtion Vol. 56 August c d e f Figure 2 Liposrcom (myxoid type) in the left femur. Iso uptke pttern in oth erly nd delyed phse in mlignnt lesion. : erlyphseimgeof 201 TlCl scintigrphy. : delyed phse imge. The tumor showed iso uptke in oth phses of 201 TlCl scintigrphy. c : Sgittl T1-weighted SE MR imge. d : Sgittl T2-weighted SE MR imge. e : Axil T1 weighted SE MR imge with ft suppression. f : Sgittl gdolinium-enhnced T1-weighted SE MR imge. The tumor, mesuring mm, showed iso intensity on T1-WI nd high intensity on T2-WI compred to the muscle. The tumor intensity ws suppressed onft-suppressedt1-wind the tumor showed strong enhncement. c d e f Figure 3 Lipom in the right femur. : erly phse imge of 201 TlCl scintigrphy, : delyed phse imge of 201 TlCl scintigrphy. The tumor showed iso uptke in oth phses of 201 TlCl scintigrphy. c : Coronl T2-weighted SE MR imge. d : Coronl T1-weighted SE MR imge. e : Coronl T1 weighted SE MR imge with ft suppression. f : Coronl gdolinium- enhnced T1- weighted SE MR imge with ft suppression. The tumor ws spindle-shped nd showed uniform high intensity on oth T1-WI nd T2-WI, mesuring cm, nd well suppressed on ft-st T1-WI. Only septum ws enhnced nd no other solid component ws evident.

5 140 H. Otsuk, et l. Thllium-201 chloride scintigrphy in soft tissue tumors c d e Figure 4 Schwnnom in the left forerm. : erly phse imge of 201 TlCl scintigrphy, : delyed phse imge of 201 TlCl scintigrphy. Tumor showed high uptke in oth erly nd delyed phse of 201 TlCl scintigrphy. c : Coronl T2-weighted SE MR imge. The tumor ws ovl-shped, mesuring mm, nd showed peripherl high intensity nd centrl low intensity. d : Coronl T1- weighted SE MR imge. The tumor showed peripherl iso- intensity nd centrl slight high intensity compred with the muscle. e : Coronl gdolinium-enhnced T1-weighted SE MR imge with ft suppression. The tumor showed centrl significnt enhncement. lower extremities showed iso uptke. Most inflmmtory diseses showed high uptke. Cliniclly - considered enign ptients (no pthology) consisted of tumorous lesions (minly lipom nd neurogenic tumor) or inflmmtory disese. These tumors re stle or remitted cliniclly. Only 2 ptients were considered low, nd these were dignosed s intrmusculr hemtom nd cyst y MRI nd CT, respectively. RI ws otined in only high uptke ptients. RI ws vrile in oth mlignnt nd enign lesions nd no sttisticlly significnt difference ws seen etween mlignnt nd enign lesions y t-test (p=0.72) (Figure 5). Figure 5 Retention Index (RI) ws clculted in 25 ptients (9 mlignnt nd 16 enign lesions). there were significnt overlp etween mlignnt nd enign lesion, nd no sttisticl difference ws oserved (p=0.72).

6 The Journl of Medicl Investigtion Vol. 56 August DISCUSSION It is importnt to evlute the nture of lesion nd differentite mlignnt from enign in the mngement of ptients with soft tissue tumors. Imging techniques re essentil nd 201 TlCl scintigrphy hs plyed n importnt role. FDG-PET is newly developed in tumor imging ut the clinicl indiction for soft tissue tumor is limited nd not so widely used compred with 201 TlCl scintigrphy (5). Thllium is potssium nlogue nd ccumultes in tumors reflecting mny fctors. There re some reports tht hve descried the utility of 201 TlCl scintigrphy in the differentition of mlignnt from enign lesions sed on the degree of 201 TlCl uptke. In dul time scnning (erly nd delyed phse), the erly phse uptke minly reflects tumor vsculrity nd the delyed phse uptke sustntilly reflects tumor viility. In our study, most of the mlignnt lesions demonstrted high uptke in oth the erly nd delyed phses. Two of the mlignnt tumors tht showed iso uptke were liposrcom. In these cses, Gdolinium-enhnced MRI ws useful to detect illdefined mlignnt soft tissue components. It is reported tht low 201 TlCl uptke is shown in welldifferentited or myxoid liposrcom (6). One of our ptients ws incidentlly detected y FDG-PET/CT for follow up of uterine cervicl cncer, nd the lesion showed high FDG uptke. The tumor ws resected 1.5 yers fter 201 TlCl scintigrphy nd ws proven s liposrcom. We were unle to determine the existence of mlignnt component t the time of 201 TlCl scintigrphy. The RI is reportedly useful for differentiting enign from mlignnt tumors. In our study, we clculted RI in high uptke ptients. The RI ws vrile in oth mlignnt nd enign lesions, nd no sttisticlly significnt difference ws oserved. We elieve tht this is due to histologicl vriility, vrile lesion size nd norml physiologicl muscle uptke. We evluted RI using plnr imges tht demonstrted n overlpped uptke in the lesion nd norml muscle. A smll lesion is sometimes msked y surrounding tissue nd my not show high uptke. Ahigh 201 TlCl uptke is more frequently seen in mlignnt tumors, ut regrdless of whether the tumor is enign or mlignnt, ccording to the histopthologicl vriety, the 201 TlCl uptke pttern cn not e the only indictor to differentite mlignnt from enign tumors. We ultimtely need to evlute the nture of tumors y comintion of severl imging techniques. REFERENCES 1. Otsuk H, Shint H, Hied M, Ymshit K, Kitmur H, Sen T, Kshihr K, Tgshir H : The retention indices of 201 Tl-SPECT in rin tumors. Ann Nucl Med 16(7) : , Sugwr Y, Kikuchi T, Kjihr M, Sen T, Ochi T, Fujii T, Mochizuki T, Skym K, Nkt S : Thllium-201 scintigrphy in one nd soft tissue tumors : comprison of dynmic, erly nd delyed scns. Ann Nucl Med 19(6) : , Nishiym Y, Ymmoto Y, Yokoe K, Kwguchi Y, Toym Y, Stoh K, Ohkw M : A comprtive study of 201 Tl scintigrphy nd three-phse one scintigrphy following therpy in ptients with one nd soft-tissue tumors. Ann Nucl Med 18(3) : , Higuchi T, Tki J, Nkjim K, Kinuy S, Nonomur A, Tsuchiy H, Bunko H, Nmur M, Tonmi N : Differentition of soft tissue hemngiom y 201Tl scintigrphy. Nucl Med Commun 24 : , Otsuk H, Grhm MM, Kuo A, Nishitni H : FDG-PET/CT findings of srcomtous trnsformtion in neurofiromtosis : cse report. Ann Nucl Med 19(1) : 55-58, Sto O, Kwi A, Ozki T, Kunisd T, Dnur T, Inoue H : Vlue of thllium-201 scintigrphy in one nd soft tissue tumors. J Orthop Sci 3 : , 1998