RADIOLOGY FOR PRACTITIONERS IMAGING OF MUSCULOSKELETAL DISEASES

RADIOLOGY FOR PRACTITIONERS IMAGING OF MUSCULOSKELETAL DISEASES http://www.lenesemedicljournl.org/rticles/57-1/doc3.pdf Nil J. KHOURY 1, George Y. EL KHOURY 2 Khoury NJ, El Khoury GY. Imging of muskuloskeletl diseses. J Med Lin 2009 ; 57 (1) : 26-46. INTRODUCTION In the recent yers, dvnces in imging hve revolutionized the medicl prctice. Since the lte 1980 s MR imging hs ecome the modlity of choice for the ssessment of musculoskeletl disorders. However, with the dvncement of CT technology through development of multidetector scnners, CT scn is gin gining grounds in the evlution of musculoskeletl diseses. Besides, ultrsound hs een slowly ut surely gining strength s very useful tool in musculoskeletl imging in prticulr for tendon nd ligment disorders nd to guide interventions. Note however, tht rdiogrphs should e lwys performed s the primry investigtion nd remin cornerstone in imging. In the following rticle we will e ddressing some specific topics tht re frequently encountered in the dily clinicl prctice outlining the use of different imging m o d l i t i e s. RADIOLOGICALAPPROACH FOR IMAGING OF PRIMARY BONE TUMORS In the pproprite clinicl setting, ptients with primry one tumors cn present with constelltion of symptoms nd signs relted to the tumor or they cn e totlly symptomtic nd the tumor discovered incidentlly on imging studies. Those with symptoms typiclly complin of pin, ltered function, nd plple mss or pthologic frcture [1]. In clinicl prctice, significnt numer of mlignnt one tumors initilly go undignosed ecuse of low index of suspicion. The prolem of under detection nd delyed dignosis ws discussed y Grimer nd Sneth [2] nd they reported tht 22% of mlignnt one tumors re initilly missed. Of these cses, 58% were inoperle or required mputtion, wheres only 15% of ptients in whom dignosis ws mde t the initil presenttion required mputtion. Erly dignosis nd prompt referrl would undoutedly improve prognosis [ 2 ]. Reching resonle differentil dignosis or specific dignosis is often complex process which requires close coopertion etween the orthopedic oncologist, rdiologist nd pthologist. When clinicin is confronted with solitry one lesion, there is wide vriety of lesions tht should e considered, ut most importntly, nonneoplstic processes should e ruled out first. Lesions to e considered should include mlignnt nd enign tumors, exuernt cllus, stress frcture, infection nd solitry metstsis. Bsed on the initil differentil dignosis or specific dignosis, ptient mngement cn tke one of three pthwys, depending on how ggressive the lesion ppers to e [3]: 1. Lesions tht re thought to e enign, stle or regressing in size cn e ignored. Exmples of such lesions include verterl hemngiom, one islnd (Figures 1, 1) nd non-ossifying firom. 2. Lesions tht re enign, ut cn e loclly destructive or hve mlignnt potentil should e followed-up with periodic imging. Such lesions include enchondrom FI G U R E 1 Incidentl finding of one islnd in the proximl humerus of 35-yer-old mn. Rdiogrph () nd xil CT scn () showing typicl sclerotic lesion with spiculted contour ( r r o w s). Deprtments of 1 Clinicl Rdiology, Americn University of Beirut Medicl Center, Lenon; 2 Rdiology nd Orthopedic Surgery, University of Iow Hospitls nd Clinics, Iow City, USA. Corresponding uthor: Nil J. Khoury, MD. Americn University of Beirut Medicl Center. Bliss Street. Beirut. Lenon. e-mil: nk01@u.edu.l

FIGURE 2 Middle-ged mn with mid left thigh pin. Rdiogrph shows rther well-defined lytic lesion in the mid femorl shft ( rrows).. Axil CT scn revels soft tissue lesion occupying the femorl one mrrow with tiny centrl clcifictions (rrows) comptile with crtilginous lesion. The dignosis is tht of n enchondrom. However, this lesion is to e followed-up ecuse of potentil mlignnt trnsformtion. c. Coronl STIR imge of oth thighs. The tumor is loulted nd of significnt incresed signl intensity, finding seen in crtilginous msses. Miniml endostel sclloping nd surrounding one mrrow edem (rrow) is seen. c (Figures 2, 2, 2c), firous dysplsi nd neurysml one cyst. 3. Lesions suspected of eing mlignnt tht require stging for locl spred nd distnt metstsis. Primry one srcoms fll under this group (Figure 3) [3]. Imging Ap p ro c h Asystemtic pproch is required for formulting short d i fferentil dignosis or suggesting specific dignosis. The pproch strts with ruling out norml vrints nd enign processes which mimic neoplsm. This is followed y crefully going over checklist to evlute solitry one lesions when neoplsm is considered. This checklist includes the ptient s ge, the loction of the lesion, rte of growth or how ggressive the lesion is, tumor mtrix, nd finlly, the type nd chrcteristics of the periostel rection formed round the lesion [3-4]. The significnce of knowing the ptient s ge hs een well emphsized in the literture. The mjority of FI G U R E 3 1 2 - y e r-old oy with Ewing s srcom. Apermetive lesion with sclerotic nd lytic components is seen involving the proximl tii. The tumor orders re ill-defined (wide zone of trnsition). There is sunurst ( r r o w s) nd onion skin ( r r o w h e d) ppernce of the periosteum denoting ggressive lesion. N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 2 7

FIGURE 4. Lytic rest metstses in the mid humerus of 55-yer-old womn. The lesion (rrows) hs ill-defined contours.. Multiple myelom in n elderly mle. Multiple punched-out lytic lesions re noted in the skull. FI G U R E 5. 3. 5 - y e r-old oy with left hip limping. There re well-defined lytic lesions ( r r o w s) involving the left femorl neck nd left ilic one. In this ge-group the findings re most proly those of Lngerhns cell histiocytosis, dignosis tht ws confirmed y ilic one iopsy. primry one tumors occur etween the second nd fourth decdes of life. A lytic one lesion occurring in ptient ove the ge of 50 yers should rise the possiility of metstsis (Figure 4) or multiple myelom (Figure 4) wheres lytic lesion in child rises the possiility of Lngerhns cell histiocytosis [1, 3] (Figure 5). The ntomic loction of the one lesion provides significnt clues to wht the dignosis might e. It is importnt to determine whether the lesion is epiphysel, FIGURE 6. Chondrolstom in n 18-yer-old mn. A well-defined lytic lesion involving the epiphysis is present (rrows) with sclerotic contour nd miniml internl clcifictions. metphysel or diphysel. Does it originte from the medullry spce, cortex or from the surfce of the one? The most frequent sites for metstsis nd multiple myelom re the spine, pelvis nd ris i.e. the xil skeleton. Primry one tumors such s Ewing s srcom or chondrosrcom often occur in the pelvis. Chondrolstoms re clssiclly locted in the unfused epiphysis or pophysis ut my present lter (Figure 6). Osteolstom hs predilection for occurring in the posterior 28 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FIGURE 7 Osteolstom in 40-yer-old mn. A lrge destructive lesion is noted involving the left posterior elements of n upper thorcic verterl ody with impingement on the spinl cnl. FIGURE 8 Gint cell tumor in 28-yer-old mn involving the proximl metphysis nd epiphysis. The lesion is lytic nd rther well defined (rrows). FIGURE 9 Awell defined lytic lesion with nrrow zone of trnsition in 9-yer-old girl. The lesion is expnsile nd involves the distl one-third of the rdius. Its wll is not clcified. Biopsy proved the presence of non-ossifying firom. elements of the verter (Figure 7). A lytic lesion in the suchondrl one of the knee epiphysis is most likely gint cell tumor (Figure 8). Lesions of the sternum re lmost lwys mlignnt, typiclly representing metstsis wheres the vst mjority of ptellr lesions re enign [3]. Rte of growth of the lesion lso known s iologic ctivity determines whether the lesion is enign or mlignnt. This cn e determined ccurtely y ssessing the m rgin of the lesion. The mrgin of the lesion is reflection of the reltive ggressiveness of the neoplstic process. A well-defined lesion with or without sclerotic m rgin (Figure 9) hs nrrow zone of trnsition (etween the lesion nd the helthy ntive one) nd is unlikely to e ggressive [5-6]. A lesion with ill-defined mrgins hs wide zone of trnsition nd most likely is n ggressive tumor. Less ggressive lesions re descried rdiogrphiclly s hving geogrphic pttern of one destruction wheres highly ggressive lesions often hve moth-eten or N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 2 9

FIGURE 12. 16-yer-old girl with tiil osteosrcom. The lesion is typiclly sclerotic denoting osteoid mtrix. FIGURE 10. Sme ptient s in Figure 3. Coronl T 1 -weighted () nd sgittl STIR () MR imges. The tumor is of low signl intensity on T1W nd of high nd low signl on STIR imges. The one nd soft tissue extent is well identified. Corticl destruction is seen on the sgittl imges, nteriorly. FIGURE 13. Solid enign periostel rection (rrow) due to stress frcture of the third mettrsl one. FIGURE 11. Chondrosrcom of the left puic one in 60-yer-old mn. The lesion (rrows) is lytic nd contins rings nd dots clcifictions. permetive ptterns of one destruction [5-6] (Figure 3, Figures 10, 10). One of the most importnt fetures tht help in ctegorizing one lesion is the tumor mtrix [7]. The mtrix is the cellulr sustnce produced y the mesenchyml cells in the tumor. Asence of rdiogrphiclly discernle tumor mtrix significntly limits our ility to come up with specific dignosis. Different mtrices re produced y different tumors ut only the chondroid nd osteoid mtrices ecome clcified nd, therefore, re rdiogrphiclly identifile. On rdiogrphs, the chondroid mtrix revels white dots, rings, c-shped nd popcorn like clcifictions (Figure 11, see lso Figure 2). Such mtrix is seen in crtilge forming tumors such s enchondrom, chondrolstom nd chondrosrcom. Osteoid mtrix hs confluent, cloud like ppernce. It is seen in lesions such s osteolstom, osteosrcom (Figure 12), myositis ossificns nd frcture cllus [7]. Another defining feture of solitry one lesions is the type of periostel rection ssocited with the lesion. T h e current thinking pertining to the periostel rections is shped y the clssic work of Edeiken nd his co-workers [8]. Periostel rections cn e divided into two types: solid or uninterrupted (Figure 13) nd interrupted (Figures 3 nd 14). There re sutypes under these two types. A solid periostel rection is lmost lwys ssocited with 30 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FI G U R E 1 6. N i n e - y e r-old oy with right ilic one hemngiom. Rdiogrphs () nd CT scn () show thick strition of the one trecule. FIGURE 14 Lmellted periostel rection ( r r o w s) with Codmn s tringle ( r r o w h e d) in 14-yer-old girl with osteosrcom. There is lrge destructive lesion of the distl femur with lrge soft tissue component contining morphous clcifictions nd one frgments. FIGURE 15. Metsttic rest cncer. Coronl reconstructed CT scn of the spine showing n ivory verter (rrowhed). Blstic metstses re lso noted in the rest of the spine. enign lesion. An interrupted periostel rection signifies n ggressive lesion, nd with few exceptions, such s fulminnt infection or fst-growing neurysml one cyst, it is lmost lwys ssocited with mlignnt t u m o r. Interrupted periostel rections re firly complex nd three sutypes hve een descried. These re the lmellted (or onion skin), sunurst (or spiculted) nd morphous. The lmellted periostel rection often produces Codmn s tringle (Figure 14). The Codmn s tringle typiclly occurs where the tumor mss reks out through the newly formed periostel lyers. T h e C o d m n s tringle is not specific for mlignnt tumors lthough most commonly seen in such conditions. It cn lso occur with osteomyelitis nd fst growing neurysml one cysts. The sunurst nd morphous periostel rections re lwys ssocited with mlignnt lesions such s Ewing s srcoms (Figure 3) [8]. Some rdiogrphic signs re dignostic of certin tumors nd cn e very useful in rriving t n ccurte dignosis [3]. Ivory verter: This description is pplied when the entire verter, especilly the verterl ody ppers densely sclerotic on rdiogrphy or CTscn. This ppernce is highly suggestive of lstic metstsis such s in prostte crcinom (Figure 15). Corduroy pttern: Denotes the presence of thick strited treculr pttern in the lesion. It is highly suggestive of hemngiom (Figures 16, 16). N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 3 1

FIGURE 18 FIGURE 17. Firous dysplsi involving the left femorl neck nd intertrochnteric region. Typicl lytic lesion with ground glss ppernce nd thick peripherl rind is present. The Rind sign: This indictes the presence of thick corticl mrgin round the lesion (Figure 17). It denotes enign, inctive or stle lesion nd is often seen in ssocition with smll rrested foci of firous dysplsi typiclly locted in the femorl neck. Ground-glss ppernce: Is rdiogrphic metphor tht descries expnsile lesions tht re neither lucent nor sclerotic, ut rther ground glss in density. This ppernce should rise the possiility of firous dysplsi (Figure 17). The fllen frgment sign: This sign indictes the presence of pthologic frcture in simple cyst, typiclly in the humerus (Figure 18). To demonstrte this sign, the Simple one cyst complicted y frcture with fllen one frgment (rrow). rdiogrphic exmintion should e tken in the upright position to llow the frctured frgment to fll down nd settle t the dependent portion of the cyst. Fluid-fluid levels: These cn e detected on MRI nd sometimes on CTexmintion. The sign is dignostic of neurysml one cyst or telngiecttic osteosrcom (Figures 19, 19) [9]. Once the presumptive dignosis of mlignnt one tumor is mde, locl stging should e performed efore Figure 19. Lrge destructive lesion of the distl femur in 22-yer-old mle with soft tissue component contining one frgments.. Axil T 2 -weighted MR imge revels multiple cystic spces with fluid-fluid level (rrow). Biopsy reveled telngiecttic osteosrcom. 32 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FIGURE 20. Synovil srcom ner the knee joint with clcifictions detected on CTscn (rrow). proceeding to iopsy. All ptients with mlignnt one tumors should lso e studied for distnt metstsis, using chest CT scn to rule out the presence of pulmonry m e t s t s i s. RADIOLOGICALAPPROACH FOR IMAGING SOFT TISSUE TUMORS There re four types of soft-tissue msses tht ptients cn present with nd they include: mlignnt soft-tissue tumors, enign soft-tissue tumors, inflmmtory lesions, nd posttrumtic msses such s myositis ossificns nd flse neurysms. Ptients with soft-tissue tumors usully present with pinless plple mss. The presence of pinful mss usully suggests n inflmmtory process. Physicins invrily request rdiogrphic exmintion which rrely yields dignostic informtion. The next step is usully n MRI which often helps in rriving t differentil dignosis nd occsionlly specific dignosis [10-11]. The most common mlignnt soft tissue tumors re srcoms nd they include mlignnt firous histiocytom (MFH), liposrcom, firosrcom nd synovil srcom. Among these the MFH is the most common, ccounting for out 24% of ll soft-tissue srcoms. Soft-tissue srcoms re reltively rre, representing out 1% of ll mlignnt tumors, ut they re still out two to three times more common thn mlignnt one tumors [10-11]. Benign soft-tissue tumors re fr more common thn soft-tissue srcoms. Lipom, desmoid tumor (ggressive firomtosis), hemngiom nd nerve-sheth tumor re the most common enign tumors [12-13]. FI G U R E 21. Neworn with lrge thigh hemngiom. Smll rounded clcifictions were noted comptile with phleoliths. Soft-tissue tumors re typiclly solitry, however, some cn present s multiple lesions. Lipom, ggressive firomtosis, neurofirom nd hemngiom cn e multiple. Certin lesions show predilection for specific ntomic loction. This is true of epithelioid srcom where more thn 40% of epithelioid srcoms occur in the hnd nd wrist [11]. The mjority of cler cell srcoms occur in close reltionship to tendons nd ligments. Imging of Soft-Tissue Tumors Rdiogrphs cn sometimes revel homogeneous low density tumor consistent with ft-contining lesion such s lipom. Clcifictions nd ossifictions cn lso e detected rdiogrphiclly. Clcifictions re seen in out one-third of synovil srcoms (Figure 20). Rounded clcifictions or clcified phleoliths re often visile in hemngioms (Figure 21). Becuse of its improved soft-tissue contrst nd multiplnr imging cpilities MRI is currently considered N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 3 3

the imging modlity of choice for studying soft tissue msses. One drwck of MRI is its limited ility in providing tissue chrcteriztion for the mjority of softtissue tumors nd lso its inility to differentite enign from mlignnt lesions [14]. Soft-tissue tumors should e imged in t lest two orthogonl plnes using T 1 nd T 2 -weighted sequences. T 1 -weighted ft-suppressed sequences without nd with IV gdolinium dministrtion re lso helpful in differentiting solid from cystic msses or tumor necrosis. Arriving t specific dignosis sed on MRI signl chrcteristics lone cn e diff i c u l t. It is lso often impossile to tell if lesion is enign or mlignnt. Mlignnt lesions, however, re typiclly lrg e (> 5 cm), deep nd hve inhomogeneous signl intensity on MRI [10, 12-13]. FIGURE 23. Low grde liposrcom involving the posterior thigh. Sgittl T 1 -weighted imge () shows predominntly high signl intensity lesion with res of low signl (rrow) nd few septtions. On STIR imge (), the lesion shows low signl intensity regions denoting suppressed ft. However there re severl non-ftty res of high signl (rrows) due to cellulr elements nd fluid. FI G U R E 2 2 Sucutneous lipom involving the shoulder region posteriorly. Axil T 1 -weighted () nd coronl T 2 -weighted () imges showing lesion tht hs high signl intensity similr to the sucutneous ft. Few thin septtions re noted within it. There re smll numer of soft tissue tumors, minly enign tumors, which hve chrcteristic or dignostic MRI findings nd they will e discussed elow [10, 12]: Lipom: This is y fr the most common enign mesenchyml neoplsm; it is the most commonly encountered soft-tissue tumor on MRI. Lipoms cn ttin lrge size. On MRI, they hve signl chrcteristics identicl with sucutneous ft where they exhiit high signl intensity on oth T 1 - nd T 2 -weighted imges (Figures 22, 22). When lipom is within muscle or etween fscil plnes, the dignosis is lmost lwys correctly mde. With multidetector CT (MDCT) nd its multiplnr nd 3D cpilities, this modlity cn esily detect lipoms nd delinete their extent. A well differentited liposrcom cn present with MRI nd CTfindings resemling lipom, however, it hs heterogenous signls on MRI nd thick septtions etween its ftty loules. Liposrcom: This is the second most common softtissue srcom ccounting for 16-18% of ll mlignnt soft-tissue tumors [11]. The lesion occurs most commonly in the extremities, prticulrly the thigh. The CT nd MRI ppernce of liposrcom correltes with the mount of ft in the lesion. Well differentited liposrcoms contin more ft thn less differentited liposrcoms [11] (Figures 23, 23). Aggressive firomtosis: This lesion is chrcterized y the prolifertion of firous tissue which cn hve loclly ggressive ehvior [12]. Aggressive firomtosis hs tendency to recur fter resection. In the lims, the lesion cn e single or multiple. The signl chrcteristics on MRI depend on its content of collgenous 34 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FI G U R E 2 4. 2 2 - y e r-old womn with recurrent soft tissue firomtosis in the left thigh. Coronl T 1 -weighted imge () shows the lesion to e isointense to muscles with sheth-like res of low signl ( r r o w). Coronl T 2 -weighted imge () shows the lesion to e of intermedite to high signl with similr sheth-like res of low signl intensity corresponding to the most firous elements. mteril. Lesions consisting primrily of cellulr collgen hve low signl intensity on T 1 - nd T 2 -weighted imges i.e. firous mteril (Figures 24, 24). Lesions rich in cellulr elements show low signl intensity on T 1 - weighted imges nd right signls on T 2 -weighted imges. Soft tissue hemngioms: These re common soft tissue tumors representing 7% of ll enign tumors. T h e y cn e sucutneous, intrmusculr or intrsynovil. L rge-vessel (cvernous) hemngioms hve chrcteristic imging ppernce on MRI. On T 1 -weighted imges, the lesion contins res of incresed signl intensity which represent ft (Figure 25). Hemngioms typiclly show mrked enhncement fter gdolinium dministrtion (Figure 25). On T 2 -weighted imges, the lesion shows high signl intensity (Figure 25c) with sometimes serpentine or loulr vessels contining centrl low signl intensity dots which represent high velocity flow voids [ 11-12]. Nerve sheth tumors: Two histologic types re identified in the extremities nd these re: enign schwnnom nd neurofirom. It is often difficult to differentite these two tumors y MRI, ut some clinicl nd imging signs cn e helpful. A schwnnom often involves the flexor surfces of the extremities nd it grows eccentriclly from the nerve. Neurofirom cn e solitry or multiple, especilly in ptients with type 1 neurofiromtosis. It typiclly grows from the center of the nerve cusing fusiform expnsion of the nerve. Neurofiroms grow slowly, ut when rpid growth is oserved, mlignnt degenertion should e considered. On MRI, peripherl nerve sheth tumors show signls c FIGURE 25. Soft tissue hemngiom of the right thigh in 14-yer-old mle. Sgittl T 1 -weighted imge () shows n isointense soft tissue lesion with re of high signl content comptile with ft. Following IV gdolinium dministrtion, sgittl T 1 W imge () shows intense heterogenous enhncement of the lesion. Axil T 2 W imge (c) : the lesion is of high signl with septtions. N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 3 5

FIGURE 26 Nerve sheth tumors -. Schwnnom in 30-yer-old womn involving the thum region. Sgittl T 1 -weighted () nd T 2 -weighted () MR imges showing loulted soft tissue mss with intermedite signl on T 1 W nd predominntly high signl on T 2 W. c d c-d. Ankle neurofirom in 56-yer-old mn. Coronl T 1 W imge (c) shows the lesion to e superficil nd isointense to muscles. Coronl T 1 W imge following IV g d o l i n i u m dministrtion revels heterogenous enhncement of the tumor. On sgittl STIR imge (e) the tumor is of incresed signl. e tht re isointense to skeletl muscle on T 1 -weighted imges nd hyperintense on fluid-sensitive sequences (T 2 W, STIR imges) (Figures 26, 26, 26c, 26d, 26e) After gdolinium injection, these tumors show vrile degrees of enhncement [10-12]. Elstofirom dorsi: This is slow-growing pseudotumor of the soft tissues which typiclly occurs on the posterolterl spect of the chest wll in the suscpulr region. On T 1 - nd T 2 -weighted imges, this lesion is nerly isointense with muscle (Figures 27, 27). Becuse of the typicl loction nd MRI signl chrcteristics, specific dignosis is lmost lwys mde nd iopsy should e voided. WHOLE BODY MR IMAGING (WBMRI) MR imging hs een proven since its erly use in the lte 1 9 8 0 s to e very sensitive in detecting one mrrow infiltrtion nd one involvement y vrious disese processes to much etter extent thn rdiogrphs. The use of W B M R I s screening tool for one mrrow infiltrtion hs een dvocted ck in 1997, in prticulr with the use of turo sequences. WBMRI hs indeed proven its efficcy in the ssessment of one metstsis (Figure 28) [15] nd multiple myelom (Figure 29, 29) [16-17]. The sequences used vry to some degree nd include minly coronl fst shorttu inversion-recovery (STIR), nd/or T 1 -weighted imges of the hed nd neck, chest, upper lims, domen, pelvis 36 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FI G U R E 2 7 Bilterl elstofirom dorsi in 59-yer-old ldy. Coronl T 1 W () nd sgittl T 2 W () MR imges revel ilterl soft tissue lesions, underneth the posterolterl musculture of the chest wll, lrger on the right nd isointense to muscles. The findings re p t h o g n o m o n i c. Figure 28. Middle-ged womn with rest cncer nd mid ck pin. Bone scn ws norml ().WBMRI () reveled high signl within mid thorcic verterl ody (rrow). This ppered on CT scn (c) to represent destructive tumor. c nd thighs. Additionl sgittl STIR nd/or T 1 -weighted of the spine [17] nd xil T 1 -weighted imges of the skull re sometimes performed. Depending on the protocol used, totl scn time rnges from 40 minutes to 1 hr 30 minutes when more thn coronl views re used. WBMRI is lso useful in the ssessment of response to chemotherpy where IV g d o- linium is sometimes used. The degree of enhncement ws shown to reflect the response to therpy wherey decresed enhncement is comptile with good response [18]. WHOLE BODY CT SCAN (WBCT) The dvent of multidetector CTscn (MDCT) hs resulted in the incresed use of CT scn in the ssessment of musculoskeletl diseses ecuse of the cpilities of cquiring very thin cuts, nd secondry 2D nd 3D reconstructed imges. CT interprettion using soft tissue or intermedite windows (in ddition to the one window setting) is very useful in detecting FIGURE 29 Elderly mn known to hve multiple myelom WBMRI using coronl STIR technique shows res of either diffuse or focl high signl involving the thorcic vertere (. rrow & rrowheds). D i ffuse ilterl femorl nd right ilic one ( r r o w) involvement is lso seen (). N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 3 7

c FIGURE 30. Coronl reconstructed CTscn of the domen nd pelvis using intermedite window setting shows previously unsuspected one mrrow metstses within the proximl shft of the left femur ( r r o w) in ptient with rest cncer.. Coronl reconstructed CTscn of the domen nd pelvis using one window setting showing the degree of extent of mixed lstic nd lytic metsttic one disese in nother ptient with rest cncer. c. Sme CT technique s in Fig. in young oy with leukemi. The extent of leukemic one involvement cn e well ssessed, seen s lytic lesions throughout the spine nd pelvic ones. The ptient ws put in rces. intrmedullry lesions not cusing corticl erosions (Figure 30). In the er of totl ody scnning, WBCT hs een recommended in the workup of newly dignosed ptients with multiple myelom [19-21], eing more sensitive thn rdiogrphs. Other uthors dvocted however the use of Positron Emission Tomogrphy (PET) in comintion with CT scn (PET/CT) s the initil workup s well s for follow-up of ptients with multiple myelom (MM) [17]. A recent reserch y Horger et l. [22] showed encourging results for the evlution of the course of medullry lesions of MM t follow-up CT, including the ssessment of lesion density nd size. CT scn is lso etter thn MRI for the ssessment of frcture r i s k. Besides, unpulished dt shows possile promising role of WBCT in detecting one metstsis. The dvntge of CT scn is tht it ssesses t the sme time the chest, domen nd pelvis for metsttic workup (Figures 30, 30c). Pulished dt shows however the importnt use of the integrted PET/CT which hs very high positive predictive vlue for one metsttis nd lymphom reching 98% [23]. PET/CT nd MRI hve lso equl sensitivity in detecting metstsis. In ddition, WBCT is very effective in ssessment of polytrumtic ptients for detection of frctures, injuries to the orgns within the chest, domen nd pelvis in ddition to evluting the ptency of the vsculr tree. SHOULDER PAIN AND ROTATOR CUFF DISEASE Shoulder pin is very common clinicl presenttion nd is commonly due to rottor cuff disese (RC). Rdiogrphic imges re frequently norml in cute settings [24]. However, in cses with chronic symptoms norml findings cn e encountered nd these include soft tissue FIGURE 31. Rottor cuff clcifictions (rrow) seen on n AP shoulder rdiogrph. 38 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FIGURE 32. Sgittl STIR imge in young mn with cute shoulder pin. There is lrge full thickness ter t the insertion site of the suprspintous tendon. The tendon gp is filled with fluid (rrow). FIGURE 33. Shoulder ultrsound.. The suprspintous tendon is enlrged nd heterogenous (rrows) with severl hypoechoic res comptile with degenertion nd tering. The middle rrow points to full thickness ter.. Different ptient. Suprspintous tendon clcifiction is present (rrow). FIGURE 34. Ultrsound guided spirtion of rottor cuff clcifictions.. The needle ( r r o w h e d s) hs its tip utting the clcifiction ( r r o w).. Aspirted white clcific mteril cn e identified within the syringe. clcifiction over greter tuerosity (Figure 31), cromioclviculr joint osteorthritis cusing impingement rottor c u ff ter nd superior displcement of the humerl hed. Since its dvent, MRI hs een proven to e highly ccurte in detecting RC injuries. It provides informtion out ter dimensions, thickness (prtil versus full thickness; complete versus incomplete) nd tendon retrction. In ddition it helps in ssessment of muscle trophy informtion out corcohumerl rch nd cuse of impingement such s thick corcocromil ligment nd cromioclviculr joint osteorthritis [25]. This helps in determining the tretment selection nd prognosis [25]. Severl sequences my e used. A ter (Figure 32) is seen s very high signl intensity focus within the tendon sustnce which is normlly of low signl intensity on ll sequences [25]. Muscle trophy is seen s loss of muscle volume nd ftty replcement eing of high signl on T 1 -weighted imges. More recently ultrsound (US) hs een more frequently used in ssessment of rottor cuff tendons nd hs proven to e powerful nd ccurte method for detection of rottor cuff ter [24, 26]. Ultrsound needs stte-of-the-rt mchine nd opertor expertise. On US, tendons pper s homogeneous hyperechoic nds. A ter is seen s hypoechoic re within the sustnce of the tendon (Figure 33), discontinuity or tendon thinning. Ultrsound lso ssesses the presence of clcifiction (Figure 33), fluid in the sudeltoid sucromil urs or shoulder joint, muscle trophy. Tendon degenertion is seen s inhomogeneity of tendon sustnce (Figure 33). Use of dynmic imging of the shoulder cn revel impingement on the suprspintous tendon nd norml humerl hed trnsltion. Moreover, US-guided tretment of RC clcifictions hs een dvocted percutneously using fine needle. The technique consists of doing lvge nd spirtion of the clcifiction fter injecting Lidocine ner the clcifiction; then frgmenttion nd spirtion of the clcifictions is done. The yield of this technique is quite effective in some series [27] (Figures 34, 34). N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 3 9

HIP FRACTURE Hip frcture is common trumtic disorder in prticulr relted to motor vehicle ccident. However, it hs prticulr detection chllenges in elderly ptients where the rdiogrphic chnges my e sutle ecuse of osteopeni (Figure 35), or ecuse the frctures my e non-displced or incomplete frctures (Figure 36). In ddition, trumtic event is not frequently elicited. Dely in detection of the frcture hs secondry high moridity. Accurte nd erly detection of the frcture hs een mde esy y MRI (Figure 35) which hs higher sensitivity then the plin rdiogrphs [28-30]. MRI shows one mrrow edem ppering s low signl on T 1 W imges nd high signl on T 2 W nd short-tu inversion recovery (STIR) imges. A frcture line is of low signl on ll sequences. Besides, MRI shows other unsuspected one nd soft tissue injury including pelvic one frcture or contusions, surrounding muscle contusions nd muscle nd tendon ters [30]. With the dvent of multidetector CT (MDCT) with 2D nd 3D reconstructed imges, CT scn is showing incresed detection ccurcy when compred to rdiogrphy nd to nlyzing xil scns lone (Figures 36, 36c, 36d) [31]. But so fr no comprtive studies etween MRI nd CT scn were performed. CT cn lso ssess detils out frctures pertinent to surgicl pproch s well s ssocited cetulr frctures. FIGURE 35 85-yer-old ldy with sudden severe right hip pin while wlking. Rdiogrphs did not revel definite frcture except for miniml sclerosis t the level of the right femorl neck ( r r o w).. MRI ws then performed. Coronl STIR imges reveled low signl intensity line ( r r o w h e d) corresponding to the sclerotic re on the rdiogrph nd comptile with old insuff i c i e n c y frcture. There ws however high intensity frcture line (rrow) lterl to it with surrounding one mrrow edem denoting cute frcture not seen on the rdiogrph. Soft tissue edem seen s high signl ws lso noted round the right hip. c d FI G U R E 3 6. 6 8 - y e r-old mn with right hip trum.. Rdiogrphs show suspicious liner frcture ner the lesser trochnter (rrow). CT scn ws then performed. -c. Coronl 2D reconstructed imges show n nterior intertrochnteric frcture (rrow in ) extending posteriorly to rech the greter trochnter (rrow in c). d. Coronl 3D reconstructed imge nicely demonstrtes the frcture (rrows). 40 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

OSTEOPOROSIS, SPINAL FRACTURES AND INTERVENTIONAL PROCEDURES Primry osteoporosis is defined s skeletl disorder chrcterized y compromise of one strength with dignostic criteri of one frgility sed on mesurement of one minerl density (BMD) nd/or presence of frcture. Four ctegories re present depending on the severity of norml BMD [32]. Osteoporosis is mjor pulic concern nd is the min cuse of verterl frcture (85%). For exmple, in the United Sttes 30 million women nd 14 million men re ffected. The importnce of this disese results from significnt incresed risk of frcture, the decrese in the qulity of life, chronic ck pin nd limittion of dily ctivities [33]. In ddition, the presence of verterl frcture is sign of incresed risk of other frctures in the skeleton (spine, hip). Verterl frctures re frequently undetected y clinicins nd under dignosed y rdiologists, rendering the importnce of recognizing these frctures on imging. An importnt note is tht unsuspected osteoporotic frcture my e detected y other imging studies performed for other resons (for exmple lterl chest X-rys) nd hence should e mentioned. Dignosis of Osteoporosis There re severl methods to mesure one densitometry. The most commonly used techniques re dul energy X-ry sorptiometry (DEXA) nd quntittive computerized tomogrphy (QCT) [32]. DEXA utilizes n X-ry source tht emits 2 photon ems of different energy nd mesures the differentil sorption of energy from these ems y tissues. QCT hs n dvntge to selectively mesure the treculr nd corticl prts of the verterl o d y. But it is less used ecuse of high rdition, limited vilility nd higher precision error. FI G U R E 3 7. O s t e o p o r o t i c frcture. Semi-quntittive method of mesurement. Lterl rdiogrph. There is frcture of mid thorcic verterl ody ( r r o w). Mesuring the height etween the lck dots of the involved verter nd the one lower to it, gives n estimte of the loss of height which is here round 38% (i.e. moderte). There is lso decresed one density in keeping with some degree of osteoporosis. Rdiogrphic Dignosis of Frctures When deling with osteoporotic frcture rdiologists should not mke dignosis only on the sis of qulittive impressions. They re however encourged to use semi-quntittive pproch descried y Lenchik et l. [33] s seen on the lterl view. In this pproch mild frcture (grde 1) hs 20-25% loss of height; moderte frcture (grde 2) 26 40% loss of height (Figure 37), nd severe frcture (grde 3) more thn 40% loss of height. Other Imging Techniques Although well centered plin rdiogrphs re sufficient for the dignosis of frcture, multidetector CT (MDCT) with sgittl reconstruction nd MRI re very sensitive for the dignosis. MRI on the other hnd is n importnt tool to differentite enign from pthologic verterl frcture, especilly in elderly ptients with osteoporosis. Signs of enign frcture include minly norml one mrrow signl (Figure 38), hypointense frcture line prllel to end-plte with or without one mrrow edem (Figures 38, 38, 38c), fluid or ir within the frctured verter, nd sence of prverterl soft tissue mss (Figure 38d) [34-35]. c d FI G U R E 3 8. Benign verterl frctures. Elderly ptient with sucute ck pin. Sgittl T 1 -weighted MR imge of the thorcic spine. There re frctures of severl verterl odies with preserved one mrrow signl comptile with enign frctures. Ahypointense line ( r r o w) is noted prllel to the upper endplte of mid thorcic ody comptile with frcture typiclly seen in enign conditions. -c. 82-yer-old mn known to hve chronic nemi presenting with cute ck pin. Sgittl T 1 -weighted () nd T 2 -weighted (c) MR imges of the spine showing diffused low intensity on T 1 -weighted imges due to red mrrow reconversion. In ddition, one verterl ody (rrow) shows low signl intensity line seen on oth sequences similr to tht descried in Fig.. It is surrounded y one mrrow edem due to cute enign frcture. d. Sgittl T 2 -weighted MR imge in n elderly ptient with verterl frcture. Fluid ( r r o w h e d s) is seen within the verterl ody typicl for enign frcture.

Cuses of Bck Pin other thn Osteoporosis Bck pin is the second most common clinicl complint encountered y primry cre physicins [36]. There is very wide spectrum of diseses cusing ck pin including degenertive, trumtic, infection/inflmmtion, neoplsm oth enign nd mlignnt, nd conditions relted to growth disturnces in peditric popultion. However, it is eyond the scope of this rticle to discuss ll these entities. In the rdiologicl evlution of ck pin, initil imging should lwys include plin rdiogrphs which give n overll ssessment in prticulr for degenertive chnge nd lignment. MR imging however hs n estlished crucil role in the ssessment of diseses cusing ck pin including degenertive disc disese, tumors, spondylodiscitis, erly spondylorthropthy, tumor extent in prticulr within the spinl cnl nd one mrrow infiltrtive processes such s metstsis (Figure 39) nd multiple myelom (Figure 40). In fct, MRI is the est imging modlity to ssess myelom. In some instnces it ws lso proven to e more sensitive thn one scn for the detection of one metstsis [37-38]. Intrvenous gdolinium is not routinely used for the ssessment of ck pin. However indictions for its use include infectious diseses, postopertive spine, in the ssessment of response to therpy in multiple myelom, focl spine tumors nd in limited cses of diffuse one mrrow chnges in order to differentite norml red mrrow from tumor infiltrtion. CT scn is helpful in some conditions such s determintion of frcture risk in myelom, extent of spinl F i g u re 40. Elderly ptient with multiple myelom nd spine involvement. Sgittl T 1 W imge show diffuse punctute low signl intensity foci within the verterl odies of the thorcic nd lumr spine. FIGURE 39 Metsttic lung cncer to the spine. Sgittl STIR imge shows complete replcement of the one mrrow of L5 verterl ody y incresed signl intensity with loss of height, nd retropulsion of the posterior cortex into the spinl cnl (rrow). frcture, spondylolysis nd in the dignosis nd ssessment of some tumors such s osteoid osteom (see lso section on WBCT). Verteroplsty nd Kyphoplsty During the lst decde, two new therpeutic procedures were introduced for the tretment of verterl osteoporotic frcture: percutneous verteroplsty nd kyphoplsty [39]. These techniques hve good short-term results regrding pin relief, functionl sttus, correcting kyphosis nd to prevent further rpid collpse. So fr however, no dt is ville with regrds to long-term results. Besides osteoporotic frcture, these interventions re lso used to tret osteolytic metstsis nd multiple myelom cusing verterl collpse. Te c h n i c l l y, verteroplsty (Figures 41, 41) con- FIGURE 41. Verteroplsty of osteoporotic frctures.. Trnspediculr needles re seen t the L1 nd L2 collpsed verterl odies.. Post cement injection. There is slight increse in the height of the treted verterl odies. 42 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FIGURE 42. Kyphoplsty of mild ut pinful enign frcture of D12 verterl ody.. Bilterl trnspediculr needles with lloons infltion.. Injected cement fter removl of the lloons. c. The end-result with cement within the confines of the ody. c FIGURE 43. Chrcot joints of the midfoot in two dietic ptients.. Sgittl T 1 WMR imge showing significnt suchondrl one mrrow chnges involving the first trso-mettrsl joint ( r r o w) with preservtion of the surrounding soft tissues.. Foot rdiogrph in dvnced Lisfrnc frcture-disloction involving the 2 n d to 5 t h t r s o -mettrsl joints. sists of plcing needle under fluoroscopic control within the verterl ody through trnspediculr or posterolterl pproch. Then cement consisting of polymethylmetcrylte polymer (PMMA) is injected until resistnce is felt y the opertor or the cement reches the posterior verterl wll. This results in filling nd expnsion of the verterl ody. The overll complictions re limited nd include minly cement lek. Neurologicl complictions re rre. The kyphosplsty technique is n evolution of the verteroplsty. It employs lloon ctheters inflted with contrst gent to restore the morphology of the collpsed verterl ody reducing the kyphosis. Then stiliztion with one cement injection is done fter removl of the lloon (Figures 42, 42, 42c). With oth techniques, more thn one verterl level cn e injected with cement t the sme session. IMAGING OF THE DIABETIC FOOT Dietic foot is rod term used to descrie vriety of clinicl prolems ffecting ptients with dietes mellitus. These prolems re the result of vsculr insuff i c i e n c y, peripherl neuropthy nd foot infections. Vsculr disorders of the feet typiclly involve lrge nd medium vessels cusing therosclerosis nd microngiopthy of the skin nd muscles. Dietic neuropthy of the foot, lso known s Chrc o t s foot or neuropthic joints, cn involve the foref o o t producing mettrsophlngel nd interphlngel joint deformities, ut is seen more commonly in the midfoot ( L i s f r n c s joint) (Figure 43) nd hindfoot (sutlr nd nkle joints). Frcture-disloctions of the Lisfrnc s joint long with flttening of the longitudinl rch of the foot re the most common fetures of neuropthic rthropthy in the dietic foot (Figure 43). Severe deformity of the nkle following neuropthic frcture is nother common rdiogrphic finding in ptients with dietic foot. Proly the most difficult prolem in terms of dignosis nd tretment is tht of infections involving the soft tissues nd the ones in the dietic foot. Generlized nd loclized fctors contriute to foot infections in ptients with dietes mellitus, including poor lood supply, norml senstion, nd minor trum. Soft tissue infections most often strt in the toes. Cellulitis nd scess formtion re commonly the result of skin infections. In the feet of dietic ptients, osteomyelitis is typiclly chronic infection contiguous with skin ulcer. Ulcers most commonly occur on skin res with high pressure. In the one, infection strts t the cortex nd most ptients with this form of osteomyelitis lck generlized symptoms. Ascess formtion nd sinus trcks re common in the soft tissues of the foot. Dignosing osteomyelitis in the dietic foot with imging techniques hs lwys een chllenge [40]. Rdiogrphy nd MRI hve ecome the N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 4 3

FIGURE 44 Dietic foot infections -. Osteomyelitis nd septic rthritis involving the first mettrso-phlngel joint ( r r o w). Rdiogrph () revels significnt destruction of the joint. Sgittl T 1 WMR imge () showing significnt norml one mrrow signl t the level of the mettrsl hed nd se of the proximl phlnx with one destruction. There is significnt overlying soft tissue edem. c. D i fferent ptient with 1 s t m e t t r s o - phlngel infection. There is n djcent soft tissue scess ( r r o w) seen on this xil T 1 -ft sturtion MR imge following IV gdolinium dministrtion. Presence of fluid collection with thick rim enhncement is dignostic of scess. d. Another ptient with similr infection. c d Sgittl STIR imge shows edem involving the 1 s t mettrsl hed (M) nd se of the proximl phlnx (P). Asmll sinus trct ( r r o w) extends from the level of the joint to the skin of the plntr spect of the foot. Joint effusion is lso present ( r r o w h e d). modlities of choice in this regrd. Rdiogrphy is still used s the initil exmintion where findings of osteopeni nd ony erosions re highly suggestive of osteomyelitis (Figure 44), ut the sensitivity of rdiogrphy in the erly stges of osteomyelitis is low nd its ility in detecting soft tissue nd mrrow normlities is limited [40-42]. The usefulness of MRI for dignosing osteomyelitis in ptients with dietic feet hs een shown y severl reports, however, the MR findings of osteomyelitis cn e simulted y other pthologic processes ffecting the dietic foot. These include neuropthic osteorthropthy nd norml iomechnicl stresses resulting from foot deformity. This mkes the interprettion of signl normlities in the mrrow difficult nd often equivocl. Another confounding fctor reltes to the fct tht mny dietic ptients referred for imging of their feet for osteomyelitis hve underlying neuropthic one chnges which cn resemle osteomyelitis on MRI [41]. To improve specificity of MRI some uthors hve clssified the MR findings in osteomyelitis of the dietic foot into two groups: 1) primry MR criteri, nd 2) secondry criteri. The primry MR criteri include decresed mrrow signl intensity on T 1 -weighted imges (Figure 44), incresed mrrow signls on T 2 - w e i g h t e d imges, nd mrrow enhncement fter intrvenous injection of gdolinium. Crig et l. [43] hve stressed tht such norml signls in the mrrow should e intense nd confluent in order to mke the dignosis of osteomyelitis with confidence. Other uthors hve shown tht fintly drk signls or reticulr non-confluent drk signls on T 1 -weighted imges often do not represent osteomyelitis [42]. The importnce of the secondry criteri lies in improving the specificity of the primry findings. T h e s e hve een recently highlighted y some investigtors [40-41]. They include: n djcent soft tissue fluid collection, i.e. n scess (Figure 44c), sinus trct (Figure 44d), sucutneous ft edem, cutneous ulcer nd corticl interruption. The MR findings in Chrcot s rthropthy of the foot should e distinguished from those of infection nd they include: preservtion of norml sucutneous ft, sence of soft tissue fluid collections, presence of suchondrl cysts nd intrrticulr loose odies (Figure 43). MUSCULOSKELETAL ULTRASOUND With the technicl dvnces, ultrsound hs een plying n importnt role in the ssessment of vrious musculoskeletl (MSK) diseses. When compred to MRI, the dvntges of ultrsound (US) include: lower cost, etter vilility, etter cceptnce y ptients, nd no contrindiction to its use. In ddition, it hs rel time cpility, so it cn e used s dynmic study [44]. It is evident from the literture tht US is cost-effective tool for focl prolem solving issues nd in guiding interventions. Although US cnnot replce MRI in mny indictions (e.g. one mrrow disese, one tumors) it should e the first line imging modlity for other indictions such s rottor cuff diseses. The min indictions for US include tendon disese minly t the level of the shoulder nd nkle (Figures 33, 33; Figure 45) [45-46], ligment injuries (e.g. nkle) [47], joint effusions (e.g. knee, hips, nkle), superficil foreign odies [48], ssessment of smll joints for inflmmtory rthropthy [49]. Ultrsound my e used lso s n djunct to MRI in the ssessment of muscle injury nd superficil MSK msses (e.g. Morton neurom) (Figure 46). It is importnt to know tht to otin est results with ultrsound, there is need for stte-of-the-rt equipment 44 Lenese Medicl Journl 2009 Volume 57 (1) N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Di s e s e s

FI G U R E 4 5. Ultrsound of the Achilles tendon (T) in n elderly mn with cute pin. There is full thickness tendon ter with tendon gp filled with fluid ( r r o w). The tendon edges re hypoechoic due to tendinopthy. FIGURE 46. Ultrsound of the foot t the level of the mettrsl heds. There re two hypoechoic lesions (rrows) in the 2 nd nd 3 rd mettrsl wes comptile with Morton s neuroms (2, 3, 4 = 2 nd, 3 rd, 4 th mettrsl heds). nd optiml exmintions should e performed y experienced opertors. Besides, ultrsound cn e used s guidnce for interventions such s injections in tendon sheth, sudeltoid succromil urs, joint or cyst spirtion, iopsy of superficil lesions nd tretment of rottor cuff clcifictions (Figure 34). REFERENCES 1. Simon MA, Finn HA. Dignostic strtegy for one nd soft-tissue tumors. J Bone nd Joint Surg [Am] 1993 ; 75-A: 622-31. 2. Grimer RJ, Sneth RS. Dignosing mlignnt one tumors. Editoril. J Bone nd Joint Surg [Br] 1990 ; 72- B : 754-6. 3. El-Khoury GY, Sundrm M. Logicl pproch to the evlution of solitry one lesions. In : Essentils of Musculoskeletl Imging, Georges Y. El-Khoury, Ed., Churchill-Livingstone, 2003 : 2-11. 4. Sundrm M, McDonld DJ. The solitry tumor or tumor-like lesion of one. Topics Mgn Reson Imging 1989 ; 1 : 17-28. 5. Lodwick GS, Wilson AJ, Frrell C et l. Determining growth rtes of focl lesions of one from rdiogrphs. Rdiology 1980 ; 134 : 577-83. 6. Lodwick GS, Wilson AJ, Frrell C et l. Estimting rte of growth in one lesions : Oserver performnce nd error. Rdiology 1980 ; 134 : 585-90. 7. Murphy Jr WA. Imging one tumors in the 1990s. Cncer 64 (4 Suppl) 1991 ; 1169-76. 8. Edeiken J, Hodes PJ, Cpln LH. New one production nd periostel rection. AJR 1966 ; 97 : 708-18. 9. Dvies AM, Cssr-Pullicino VN, Grimer RJ. The incidence nd significnce of fluid-fluid levels on computed tomogrphy of osseous lesions. Br J Rdiol 1992 ; 65 : 193-8. 10. Krnsdorf MJ, Murphy MD. Rdiologic evlution of soft-tissue msses : A current perspective. AJR 2000 ; 175 : 575-87. 11. Bemn FD, Krnsdorf MJ, Andrews TR et l. Superficil soft-tissue msses : Anlysis, dignosis, nd differentil considertion. RdioGrphics 2007 ; 27 : 509-23. 12. Frssic FJ, Thompson RC. Evlution, dignosis, nd clssifiction of enign soft-tissue tumors. J Bone Joint Surg [Am] 1996 ; 78-A: 126-40. 13. Simon MA, Finn HA. Dignostic strtegy for one nd soft-tissue tumors. J Bone Joint Surg [Am] 1993 ; 75-A : 622-31. 14. Crim JR, Seeger LL, Yo Let l. Dignosis of soft-tissue msses with MR imging : Cn enign msses e differentited from mlignnt ones? Rdiology 1992 ; 85 : 581-6. 15. Eustce S, Tello R, DeCrvlho V et l. A comprison of whole-ody turostir MR imging nd plnr 99mTcmethylene diphosphonte scintigrphy in the exmintion of ptients with suspected skeletl metstses. AJR 1997 ; 169 : 1655-61. 16. Angtuco EJC, Fsss A B T, Wlker R, Sethi R, Brlogie B. Multiple myelom : clinicl review nd dignostic imging. Rdiology 2004 ; 231 : 11-23. 17. Mullign ME, Bdros AZ. PET/CT nd MR imging in myelom. Skeletl Rdiol 2007 ; 36 : 5-16. 18. Noss-Grci S, Moehler T, Wsser K et l. Dynmic contrst-enhnced MRI for ssessing the disese ctivity of multiple myelom : comprtive study with histology nd clinicl mrkers. J Mgn Reson Imging 2005 ; 22 : 154-62. 19. Mhnken AH, Wilderger JE, Gehur G et l. Multidetector CTof the spine in multiple myelom : comprison with MR imging nd rdiogrphy. Am J Roentgenol 2005 ; 45 : 716-24. 20. H o rger M, Clussen CD, Bross-Bch U et l. W h o l e - o d y low-dose multidetector Row-CTin the dignosis of multiple myelom : n lterntive to conventionl rdiogrphy. Europen Journl of Rdiology 2004 ; 54 : 289-97. 21. Horger M, Fritz J, Vogel M et l. Myelom stging with the id of the whole-ody unenhnced low-dose MDCT (WBLD-MDCT) nd correltion with hemtologicl prmeters : preliminry results. Scientific Exhiit ; C-584 Europen Congress of Rdiology, Vienn, Mrch 9-13, 2007. 22. H o rger M, Brodoefel H, Vogel M et l. Whole-ody lowdose nonenhnced multidetector computer tomogrhy survey of oth osteolysis nd medullry involvement in ptients with mutiple myelom referred for therpy response monitoring receiving isphosphontes. Scientific Exhiit ; C-585 Europen Congress of Rdiology, Vi e n n, Mrch 9-13, 2007. 23. Tir AV, Herfkens RJ, Gmhir SS, Quon A. Detection of one metstses : ssessment of integrted FDG PET/CT imging. Rdiology 2007 ; 243 : 204-11. 24. Moosiksuwn JB, Miller TT, Burke BJ. Rottor cuff ters : clinicl, rdiogrphic, nd US findings. Rdio- Grphics 2005 ; 25 : 1591-1607. N. J. KHOURY, G. Y. EL K H O U RY Imging of Muskuloskeletl Diseses Lenese Medicl Journl 2009 Volume 57 (1) 4 5