14 Staging of Lung Cancer with MDCT

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1 Stging of Lung Cncer with MDCT Stging of Lung Cncer with MDCT P. M. Boiselle CONTENTS 14.1 Introduction T-Sttus T-1 nd T-2 Lesions T-3 nd T-4 Lesions N-Sttus N-2 nd N N M-Sttus Summry 213 References Introduction Lung cncer is the leding cuse of cncer mortlity in the United Sttes, with deths from this disese surpssing the comined totl of deths from cn cers of the rest, colon, nd prostte comined (Greenlee et l. 2000). Accurte stging of non smll cell lung cncer (NSCLC) is of criticl im por tnce in order to determine which ptients re most likely to enefit from surgicl resection, the only true hope for cure from this disese (Jett et l. 1997). The Interntionl System for Stging Lung Cncer, in clud ing the TNM susets nd stge groupings (T les 14.1 nd 14.2), provides importnt informtion for estimting prognosis nd plnning pproprite therpy (Mountin 1997). For exmple, ptients with Stge IA disese hve reltively high cure rte fol low ing surgicl resection, wheres ptients ct e go rized s hving disese consistent with stges IIIB or IV hve much poorer prognosis nd re unlikely to enefit from surgicl resection. The stging sys tem lso provides helpful informtion for entering p tients into pproprite clinicl trils, P. M. Boiselle, MD Director of Thorcic Imging, Beth Isrel Deconess Medicl Center, Assistnt Professor of Rdiology, Hrvrd Medicl School, Deprtment of Rdiology, 330 Brookline Avenue, Bos ton, MA 02215, USA compring dif fer ent tretment regimens, nd evluting new prog nos tic fctors (Mountin 2002). Despite its recognized limittions, CT is consid ered the imging study of choice for the initil stg ing evlution of ptients with NSCLC (McLoud 2002). The recent dvent of MDCT ffords sig nifi cnt dvntges over single-detector helicl CT scn ners, including fster scnning, improved res o lu tion, etter vsculr enhncement nd higher qul i ty multiplnr reformtion nd 3-D re con struc tion imges (Choi nd Boiselle 2002). These dvntges hve the potentil to enhnce the ility to ccurtely stge lung neoplsms. This chpter re views the potentil contriutions nd reltive lim i t tions of MDCT with regrd to ssessing the T (pri m ry tumor), N (nodl) nd M (distnt metstses) components of the Interntionl System for Stging Lung Cncer T-Sttus T-1 nd T-2 Lesions MDCT scnners hve the potentil to enhnce the detection of smll lung cncers y llowing for the use of nrrower collimtion thn is routinely em ployed with single detector CT scnners. For ex m ple, it hs een shown tht thin-collimtion imges re more sensitive thn thick-collimtion imges for detecting smll, sucentimeter lung nodules (Nishi et l. 2000). Thin-collimtion imges lso provide more c cu rte chrcteriztion of nodules thn thick-col li m tion imges, especilly with regrd to the iden ti fiction of clcifiction within nodules nd the s sess ment of nodule mrgins. These re importnt fctors for determining the likelihood tht nodule is either enign or mlignnt (McLoud 2002). A unique feture of MDCT is the ility to ret ro spec tive ly crete imges with collimtion tht is nr row er thn the vlue tht ws prospectively em ployed (Choi nd Boiselle 2002). In

2 206 Tle TNM Descriptors P. M. Boiselle Primry tumor (T) TX Primry tumor cnnot e ssessed, or tumor prov en y the presence of mlignnt cells in sputum or ronchil wshings ut not visulized y imging or ron cho s co py T0 No evidence of primry tumor Tis Crcinom in situ T1 Tumor < 3 cm in gretest dimension, surrounded y lung or viscerl pleur, without ronchoscopic evidence of invsion more proximl thn the lor ronchus* (ie, not in the min ronchus) T2 Tumor with ny of the following fetures of size or extent: >3 cm in gretest dimension Involves min ronchus, >2 cm distl to the crin Invdes the viscerl pleur Associted with telectsis or ostructive pneu moni tis tht extends to the hilr region ut does not in volve the entire lung T3 Tumor of ny size tht directly invdes ny of the following: chest wll (including superior sulcus tumors), diphrgm, medistinl pleur, prietl pericrdium; or tumor in the min ronchus <2 cm distl to the crin, ut without involvement of the crin; or ssocited telectsis or ostructive pneumonitis of the entire lung T4 Tumor of ny size tht invdes ny of the following: medistinum, hert, gret vessels, trche, esophgus, ver te rl ody, crin; or tumor with mlignnt pleurl or pericrdil effusion, or with stellite tumor nodule(s) within the ipsilterl primry-tumor loe of the lung Regionl lymph nodes (N) NX Regionl lymph nodes cnnot e ssessed N0 No regionl lymph node metstsis N1 Metstsis to ipsilterl perironchil nd or ip si lt er l hilr lymph nodes, nd intrpulmonry nodes in volved y direct extension of the primry tumor N2 Metstsis to ipsilterl medistinl nd/or sucrinl lymph node(s) N3 Metstsis to contrlterl medistinl, con trlt er l hilr, ipsilterl or contrlterl sclene, or su pr clv ic u lr lymph node(s) Distnt metstsis (M) MX Presence of distnt metstsis cnnot e ssessed M0 No distnt metstsis M1 Distnt metstsis present * The uncommon superficil tumor of ny size with its in v sive component limited to the ronchil wll, which my ex tend proximl to the min ronchus, is lso clssified T1 Most pleurl effusions ssocited with lung cncer re due to tumor. However, there re few ptients in whom multiple cytopthologic exmintions of pleurl fluid show no tumor. In these cses, the fluid in nonloody nd is not n exudte. When these elements nd clinicl judgment dictte tht the effusion is not relted to the tumor, the effusion should e excluded s stging element nd the ptient s disese should e stged T1, T2, or T3. Pericrdil effusion is cls si fied ccording to the sme rules. Seprte metsttic tumor nodule(s) in the ipsilterl nonprimry-primry loe(s) of the lung lso re clssified M1 (From Mountin 1997) Tle Stge Grouping TNM Sujects* Stge TNM Suject c. Crcinom in situ IA T1NOM0 IB T2NOM0 IIA T1N1M0 IIB T2N1M0 T3N0M0 IIIA T3N1M0 T1N2M0 T2N2M0 T3N2M0 IIIB T4N0M0 T4N1M0 T4N2M0 T1N3M0 T2N3M0 T3N3M0 T4N3M0 IV Any T Any N M1 * Stging is not relevnt for occult crcinom, designed TXN0M0 (From Mountin 1997) order to op ti ml ly chrcterize detected nodule, it is im por tnt to retrospectively otin imges through the nodule with the nrrowest collimtion possile (0.5 mm to 1.25 mm, depending upon the CT mn u fc tur er). The ility to otin high qulity multiplnr nd 3-D reconstruction imges from routine MDCT studies hs the potentil to further improve nodule detection nd chrcteriztion. For exmple, it hs een demonstrted tht multiplnr coronl nd sg it tl reformtted imges increse the rte of lung nodule detection compred to xil imges (Fig. 14.1) (Eiel et l. 2000). Moreover, multiplnr reformtted imges cn lso e used to improve c cu rte locliztion of nodules. For exmple, mul ti pl nr reformtted imges cn e used to id pre op er tive locliztion of smll nodules prior to video-ssisted thorcoscopic surgery nd to en hnce ccurte stging of primry tumors with re spect to fissurl involvement (Fig. 14.2). In order to optimize the qulity of multiplnr reformtted im g es, it is importnt to choose

3 Stging of Lung Cncer with MDCT 207 Fig Vlue of 2-D multiplnr reconstruction imges in lung nodule detection.. Coronl reconstruction mximl intensity projection imge shows two smll lung nodules in left lower loe (rrows).. Axil imge from originl CT dtset shows the lrger of the two left lower loe lung nod ules locted centrlly (curved open rrow). This nodule ws initilly overlooked on the xil imge ut ws redily de tect ed on the reformtion imges. Centrlly locted nodules re more esily detected on multiplnr reformtion imges thn on xil imges (Reprinted with permission from Choi nd Boiselle 2002) Fig Improved ssessment of reltionship of neoplsm to fissure with multiplnr reformtion imge.. Frontl chest rdiogrph shows nodule in right upper loe (rrow).. Axil CT imge confirms the lung nodule nd shows spic u lt ed mrgins, consistent with neoplsm. Reltionship to fis sure is not well demonstrted. c. Sgittl reformtion mx i ml intensity projection imge demonstrtes extension of the nodule cross the mjor fissure into the djcent superior segment of the right lower loe. Also note fissurl thickening (rrow) c

4 208 P. M. Boiselle the nrrowest col li m tion possile nd to use t lest 50% overlpping reconstruction intervl (Choi nd Boiselle 2002) T-3 nd T-4 Lesions The most importnt role of imging in the s sess ment of the primry tumor (T) is to id iden ti fi c tion of T-3 (potentilly resectle) lesions nd to ccurtely distinguish them from T-4 (generlly un re sec t le) lesions (Tle 14.1). With regrd to T-3 lesions, preopertive identifiction of chest wll in v sion ids surgicl plnning ecuse such lesions require en loc resection of the lung neoplsm nd djcent chest wll (McLoud 2002). CT hs limited ility to detect chest wll in v sion: The only relile indictors of chest wll in v sion on CT re the identifiction of ri destruction nd the extension of mss eyond the ris into the djcent chest wll (Quint et l. 1995). It is im por tnt to e wre tht the identifiction of pleurl thick en ing djcent to mss is not necessrily rep re sen t tive of invsion of the prietl pleur y tu mor, e cuse similr ppernce my e produced y locl firous dhesions (McLoud 2002). Due to its ility to routinely provide thin col li - m tion xil imges nd high qulity multiplnr reformtion imges, it is likely tht MDCT will led to n improved ccurcy for detecting chest wll in v sion (Fig. 14.3). However, future studies re nec es sry to determine the impct of this new technol o gy on this spect of stging. Becuse of its superior contrst resolution, MR hs slight dvntge over CT in its ility to ccurtely predict chest wll in v sion (Fig. 14.3) (McLoud 2002). MR my thus e helpful second-line prolem-solving tool for cses tht re indeterminte for chest wll invsion y CT imging. Superior sulcus tumors re defined s lung cn cers tht occur in the extreme lung pex. Such le sions re potentilly resectle, unless there is ev i dence of involvement of the rchil plexus, su cl vi n rtery, or djcent verterl ody. MR is considered the study of choice for ssessing for in volve ment of these structures, prticulrly with re grd to spinl nd rchil plexus involvement (McLoud 2002). However, for ptients with con trin di c tions to MR imging (such s the presence of pcemker), the high qulity of coronl nd sg it tl reformtted imges provided y MDCT (Fig. 14.4) provide resonle imging lterntive. Future stud ies re necessry to compre the c cu r cy of multiplnr reformtion CT imges with direct mul ti pl nr MR imges in the stging evlution of these lesions. As defined in Tle 14.1, T-4 lesion is defined y invsion of vitl structures, such s the me di sti num, hert, gret vessels, trche, crin, esophgus, or verterl ody. T-4 lesions re generlly con sid ered unresectle, lthough exceptions re mde for certin cses t some highly specilized centers. Al though direct Fig Chest wll invsion from peripherl lung cncer on CT nd MR imging.. Sgittl multiplnr reformtion CT imge demonstrtes peripherl mss in right upper loe, with extension into chest wll (rrow) etween upper pos te ri or ris. Chest wll invsion ws not well demonstrted on the originl xil imges.. Sgittl T-1 weighted MR imge of sme ptient. The higher contrst resolution of MR results in slightly etter demonstrtion of the tumor infiltrting the ft etween the posterior ris (rrow)

5 Stging of Lung Cncer with MDCT 209 Fig Apicl lung tumor. Coronl () nd sgittl () multiplnr reformtion CT imges demonstrte right pi cl lung mss. The reformtion imges showed the extent of tumor to greter detil thn xil imges (not shown). Al though MR is the study of choice for superior sulcus tumors, MDCT with multiplnr reformtion imges is resonle lterntive for ptients with contrindictions to MR invsion of vitl structures is some times clerly delineted with xil CT imges (Fig. 14.5), it is not lwys possile to distinguish con ti gu i ty of tumor with the medistinum from c tu l invsion of vitl medistinl structures (McLoud 2002). Severl technicl fctors cn en hnce the ssessment for invsion of vitl structures using MDCT, including the use of intrvenous con trst enhncement, selection of nrrow collimtion (less thn or equl to 3 mm), nd the cretion of multi pl nr reformtion nd 3-D reconstruction imges (Figs ). Despite the importnt tech no log i cl dvnces fforded y MDCT, however, some cses will still remin indeterminte y CT imging. Approximtely one decde go, the Rdiologic Di g nos tic Oncology Group (RDOG) study prospec tive ly compred CT nd MR imging in the pre op er tive stging evlution of ptients with non smll cell lung cncer (We et l. 1991). This study showed tht MR ws slightly more ccurte thn CT for de ter min ing invsion of vitl medistinl vs cu lr struc tures, lthough this difference ws not sttisticlly significnt. MR should e considered s sec ond-line, prolem-solving tool for cses tht re in de ter mi nte for medistinl invsion y CT, es pe cil ly in ptients who hve contrindiction to io di nt ed contrst gents. Indeed, it cn e difficult to ssess for invsion of vsculr structures on un en - hnced CT studies. Considering the development of significnt dvnces in oth CT nd MR in the pst decde, new prospective tril is needed to ssess the reltive merits nd respective roles of these techniques in the stging evlution of NSCLC. Fig Advnced-stge, inoperle non-smll cell lung cn cer. Contrst-enhnced xil CT imge of ptient with ex ten sive non-smll cell lung cncer demonstrtes extensive me di s ti nl involvement, including invsion of the irwy t level of crin. Note extension of neoplsm into proximl minstem ronchi (rrows). Also note centrlly ostructing tumor, with ssocited left upper loe collpse

6 210 P. M. Boiselle Fig Improved ssessment of centrl irwy invsion with 3-D reconstruction imge.. Axil, contrst-enhnced CT t level of orticopulmonry window shows lrge nodl mss compressing the crin. Origin of right minstem ron chus (rrow) is severely nrrowed ut is difficult to fully s sess ecuse of its olique orienttion with respect to the xil plne.. 3-D externl volume rendering of irwy re vels irregulr deformity of distl trche nd crin, s well s severe nrrowing of proximl right minstem ronchus (rrow) with distl ptency. Compred with xil imges, the 3-D imges provided more ccurte ssessment of the over ll extent of irwy involvement (Reprinted with permission from Boiselle et l. 2002) Fig Invsion of superior cv. Coronl reformtion im ge shows centrl neoplsm (N) invding the superior ven cv, consistent with T-4 lesion. Also note extensive neoplstic involvement of the medistinum, encsing the ort nd other vsculr structures 14.3 N-Sttus The nodl sttus (N) provides importnt in for m tion for determining prognosis nd plnning p pro pri te therpy. For exmple, ptient with T-1 or T-2 lesion nd no evidence of regionl metsttic nodl disese (N0) or distnt metstses (M0) hs rel tive ly fvorle prognosis (pproximtely 65% 5-yer survivl) following surgicl resection (Mountin 1997). On the other hnd, ptient with T-1 or T-2 lesion with metsttic disese to contrlterl medistinl lymph nodes (N3) ut no distnt me tsts es (M0) hs poor prognosis (less thn 10% 5-yer survivl rte) nd is considered inoperle (Mountin 1997) N-2 nd N-3 With regrd to the ssessment of medistinl lymph nodes, CT relies upon ntomic fetures, most no t ly lymph node size, in order to distinguish etween enign nd mlignnt lymph nodes. Although very erly investigtions with CT suggested sensitivities nd specificities comprle to

7 Stging of Lung Cncer with MDCT 211 Fig Invsion of left trium.. Axil CT imge shows cen trl lung cncer resulting in ostruction of right upper loe ronchus (rrow).. Coronl reformtion imge dem on strtes invsion of superior spect of left trium (rrow) [Cse courtesy of Dr. Kyung S. Lee, Smsung Medicl Center, Seoul, Kore] medistinoscopy, susequent, more thorough studies hve shown tht the ccurcy of CT is significntly lower (Boiselle 2002). For exmple, study tht employed extensive nodl smpling nd correltive CT imging of nodl sttions showed reltively low sensitivity (62%) nd specificity (64%) for predicting neoplstic in volve ment using 1 cm s the upper limits of norml size for short xis of lymph nodes (McLoud et l. 1992). These results emphsize the limittions of using nodl size to determine nodl sttus: Enlrged nodes my e hyperplstic rther thn neoplstic, nd smll nodes my hror foci of metsttic dis ese (Boiselle et l. 1998). Becuse of the low specificity of CT, enlrged nodes must e iopsied for stging purposes. It is importnt to e wre tht enign nodes s lrge s 4 cm in dimeter hve een descried in ssocition with ronchogenic crcinom (Jett et l. 1997). Flse-positive nodes most often occur in the setting of postostructive pneumonitis from centrlly o struct ing neoplsm (Fig. 14.9). Similr to CT, MR relies predominntly upon nod l size for predicting neoplstic involvement. Thus, MR hs similr limittions to CT in the s sess ment of medistinl lymph nodes. Historiclly, the direct multiplnr imging cpility of MR hs of fered reltive dvntge over xil CT imges in the ssessment of certin nodl sttions, such s the orticopulmonry window nd sucrinl nodl sttions (Boiselle et l. 1998). However, with the il i ty of MDCT to routinely perform high-qulity mul ti pl nr reformtion imges, this is no longer sig nifi cnt distinction. MR hs lso historiclly of fered reltive dvntge over CT in the ssessment of hilr nodes, prticulrly when intrvenous con trst en hnce ment is suoptiml or sent on CT (Boiselle et l. 1998). With the improved vsculr en hnce ment of hilr vessels fforded y MDCT, Fig Flse-positive lymph node. Axil CT imge shows centrl neoplsm ostructing the right upper loe ronchus, with ssocited post-ostructive telectsis nd pneu moni tis. Enlrged precrinl lymph node (rrow) proved to e hyperplstic t iopsy, with no evidence of neoplsm

8 212 P. M. Boiselle this dis tinc tion is no longer relevnt. However, for p tients who hve contrindiction to iodinted con trst gents, MR my e helpful prolem-solving tool if the st tus of the hilr structures is in de - terminte y CT imging. Despite its recognized limittions, CT still plys severl importnt roles in nodl stging (Boiselle 2002). First, y identifying nd loclizing lymph nodes, CT ids the selection of the most pproprite iopsy procedure (medistinoscopy, me di s t- i no t o my, thorcoscopy, trnsronchil needle spirtion, or percutneous CT-guided iopsy) for stging purposes. For exmple, orticopulmonry window lymph nodes re not ccessile y cervicl me di s t- i nos co py nd thus require nother method of iopsy such s nterior or prsternl medistinotomy (Fig ). Second, CT cn e used to guide nodl iopsies. Although preliminry studies (Protopps nd Westcott 1997; Zwischenerger et l. 2002) hve shown promising results using CT-guided per cu - t ne ous i op sy for medistinl nodl stging, this tech nique currently plys limited role compred to other i op sy procedures. In recent study of 89 p tients who underwent CT-guided iopsy of me di - s ti nl lymph nodes greter thn 1.5 cm in dimeter, dignosis ws mde in 78% of cses (Zwischenerg er et l. 2002). Although virtully ll nodl sttions were c ces si le with this technique, these in ves - ti g tors em ph size tht orticopulmonry nodes cn e dif fi cult to ccess with this method. Bsed upon their find ings, Zwischenerger et l. con clud ed tht CT-guid ed iopsy should ply lrger role in stging lung cncer. CT cn lso e used to guide trnsronchil i op sy procedures, either indirectly with virtul Fig Coronl reformtion imge shows lrge nodl mss (N) in the orticopulmonry window. This nodl st tion is not ccessile y cervicl medistinoscopy ron cho s co py or directly with CT-fluoroscopy. Such guid nce hs een shown to improve the ccurcy nd reduce the time of this procedure (Vining et l. 1996; Golderg et l. 2000). An emerging role of CT involves the provision of complementry ntomic informtion for cor re - l tion with physiologic FDG-PET studies (Boiselle et l. 1998). Severl recent studies suggest tht comined ntomic nd physiologic imging using CT nd FDG PET is more ccurte thn PET imging lone (Gupt et l. 1999, Mgnni et l. 1999, Vn s teen k i ste et l. 1997, 1998). For exmple, in study tht prospectively compred the ccurcy of CT scn ning, FDG PET imging linded to CT, nd FDG PET visully correlted with CT in the detection of N2 metsttic medistinl lymph nodes in ptients with NSCLC, the highest dignostic ccurcy ws oserved when comined CT-PET pproch ws employed (Vnsteenkiste et l. 1997). Thus, CT nd FDG PET should e considered s com ple men t ry rther thn competitive imging techniques. Recently, integrted PET-CT hs ecome ville nd hs een shown to e more ccurte thn CT lone, PET lone, or conventionl visul correltion of PET nd CT (Lrdinois 2003). At present, integrted PET-CT is the most ccurte method of nodl stging for non-smll lung cncer N-1 CT hs lso een shown to hve low sensitivity nd specificity for ssessing hilr lymph node me tsts es. The evlution of hilr lymph nodes hs ecome n importnt fctor in the selection of ptients with erly lung cncer nd poor pulmonry reserve for miniml resection procedures such s seg men t ec to my nd wedge resection (Boiselle 2002). It hs re cent ly een suggested tht hilr nodl contour my e more ccurte predictor of metsttic in volve ment thn nodl size (Shimoym et l. 1997). In study tht ssessed the ility of CT to detect hilr nodl metstses, Shimoym et l. (1997) clssified lymph nodes with stright or concve mrgins to the lung s enign nd those with convex mrgins s mlignnt. Using this criterion, these investigtors reported reltively high sensitivity (87%) nd spec i fic i ty (88%) for detecting hilr nodl metstses. Future studies involving lrger numers of ptients re necessry to confirm these promising results.

9 Stging of Lung Cncer with MDCT M-Sttus Extrthorcic metstses re present in significnt proportion of ptients with newly dignosed NSCLC. In most cses, clinicl symptoms or lortory dt normlities will signl the presence of distnt metstses nd guide the imging evlution of f fect ed ptients. In recent yers, the occurrence of cliniclly silent rin metstses hs received in cres ing ttention, prticulrly mong ptients with denocrcinom. At present, the role of imging in the evlution of silent metstses remins somewht controversil. The discussion of extrthorcic metstses in this chpter will e limited to the drenl glnd, n im por tnt site of metsttic disese tht is generlly in clud ed on ll stging thorcic CT scns. Although the drenl glnd is reltively common site of met stt ic disese in NSCLC, it is importnt to e wre tht the mjority of drenl lesions detected in p tients with NSCLC represent enign denoms (McLoud 2002). For stging purposes, it is criticlly importnt to distinguish denoms from me tsts es. A non-invsive dignosis of denom is sed pri m ri ly upon the presence of lrge lipid-lden cells within most denoms. On unenhnced CT scns, denoms re chrcterized y Hounsfield unit (HU) mesurement of less thn 10. This cri te ri on is ssocited with sensitivity of 71% nd spec i ficity of 98% (Myo-Smith et l. 2001). The spec i ficity pproches 100% when other fetures such s size (<4 cm), shpe (round), nd mrgins (smooth) re lso considered (Myo-Smith et l. 2001). An d vn tge of MDCT is the ility to retrospectively o tin imges with nrrow collimtion, which my id the chrcteriztion of drenl lesions with regrd to ccurtely ssessing density nd mrgins. Importntly, out 30% of denoms will demon strte HU >10 on CT scns (Myo-Smith et l. 2001). MR cn e helpful for further ssessment of such le sions. On MR imging, the lipid content of denoms cn e demonstrted using chemicl shift imging, which is sed upon the different reso nnce fre quen cy rtes of protons in ft nd wter molecules (Myo-Smith et l. 2001). Tissues tht con tin oth lip id nd wter will demonstrte signl loss (drk sig nl) on out-of-phse imges compred to in-phse imges. This technique is highly ccurte for dignosing denoms, with reported sensitivities rng ing from 81% to 100% nd specificities rnging from 94% to 100% (Myo-Smith et l. 2001) Summry Despite its limittions, CT remins the initil im g ing modlity of choice for the stging ssessment of ptients with NSCLC. MR plys n importnt com ple men t ry role in selected elements of stging, pr tic u lr ly in the evlution of superior sulcus lesions nd in the ssessment of chest wll or medistinl invsion. It my lso e helpful s secondry, pro lem-solving tool for ssessment of the vsculr in v sion nd hilr structures for ptients with con trin di c tions to iodinted intrvenous contrst. Im por tnt ly, oth CT nd MR re limited y their relince upon ntomic prmeters. Comined n tom ic nd physiologic imging with CT nd FDG-PET is currently the most ccurte non-invsive method ville for stging NSCLC. Considering the development of significnt d vnc es in oth CT nd MR in the pst decde, s well s the dvent of PET imging, prospective tril is needed to ssess the reltive merits nd respective roles of these three techniques in the stging evlution of NSCLC. Acknowledgements. I grte ful ly cknowledge the contriution of Fig from Dr. Kyung S. Lee, Smsung Medicl Center, Seoul, Kore nd the expert photogrphy of Michel Lrson, Beth Isrel Deconess Medicl Center, Boston, MA. References Boiselle PM (2002) Stte-of-the-rt thorcic lymph node im g ing. In: Boiselle PM, White CS (eds) New techniques in thorcic imging. Dekker, New York, pp Boiselle PM, Ptz EF, Vining DJ et l (1998) Imging of me di - s ti nl lymph nodes: CT, MR, nd FDG PET. RdioGrphics 18: Boiselle, Reynolds, Ernst (2002) Multiplnr nd 3-D im g ing of the centrl irwys with multidetector CT. AJR 179:302 Choi RC, Boiselle PM (2002) Multidetector helicl CT. In: Boiselle PM, White CS (eds) New techniques in thorcic imging. Dekker, New York, pp Eiel R, Tuerk T, Huer AM et l (2000) Multi-slice thorcic CT for detection of pulmonry nodules: study on coronl nd sgittl STS-MIPS nd MPRS (strct). R di ol o gy 217:384 Golderg SN, Rptopoulos V, Boiselle PM et l (2000) Im proved dignostic yield for trnsronchil medistinl lymph node iopsy using CT-fluoroscopic guidnce. R di - ology 216: Greenlee RT, Murry T, Bolden S et l (2000) Cncer sttistics, CA Cncer J Clin 50:7 33

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