Arch Orthop Trauma Surg (1990) 109 : 89-93
°fOrthopaedic andTraumaSurgery © Springer-Verlag 1990
Digital subtraction angiography in musculoskeletal tumors and other conditions J. Kold~ 1, H. Zidkovd I, J. Sprindrich 1, and Z. Mat~jovsk~ 2 1Clinic for Diagnostic Radiology and 2Clinic for Orthopedic Surgery, Institute for Further Education of Physicians and Pharmacists, Prague, Czechoslovakia
Summary. O n e h u n d r e d and forty consecutive D S A examinations of various musculoskeletal diseases were analyzed with respect to the contributions and/or limits of this m o d e r n diagnostic imaging modality. A n g i o g r a phy remains the imaging tool of choice for m a n y benign and malignant o r t h o p e d i c conditions of b o n e s and soft tissues, mainly w h e n M R I is still not generally available. It remains indispensable for embolization and/or local c h e m o t h e r a p y . D S A has the advantage of being less invasive and it also surpasses analog a r t e r i o g r a p h y in better visualization of vascular patterns h i d d e n in hyperostosis, sclerosis, and metallic shadows. A n g i o g r a p h i c investigations, w h e n necessary, should therefore start with DSA.
Articles about digital subtraction a n g i o g r a p h y ( D S A ) in the world's medical literature emphasize its undisputed advantages and merits in cardiovascular diagnostics [6, 18]. F o r o r t h o p e d i c problems, the effectiveness of D S A has g o n e grossly unnoticed, with only a few exceptions [1, 4, 8, 10, 12, 17], reporting often on limited personal experience with individual observations or on certain types of lesions only. S o m e specialists still believe that the resolution capacity of D S A for small and pathological vessels is inferior, a l t h o u g h the m o d e r n generations of D S A satisfactorily solve this initial p r o b l e m [2, 7, 9]. In the Clinic for Diagnostic R a d i o l o g y I L F in Prague, a D S A unit has b e e n used for the P r a g u e B o n e T u m o r Register during the past years. T h e aim of this p a p e r is to evaluate o u r experiences with this imaging m o d a l i t y in o r t h o p e d i c problems, mainly with respect to t u m o r o u s and tumor-like conditions of the musculoskeletal system.
Clinical survey and method One hundred and forty consecutive patients indicated for pre- or postoperative angiography are considered in this survey. The na-
Offprint requests to: Prof. MUDr Jaromfr Kolfif- DrSc, Clinic for Diagnostic Radiology ILF Budfnova 2, 18081 Prague 8-Bulovka, Czechoslovakia
ture of their diseases was subsequently verified histologically. The overwhelming majority of lesions (101) were found in the extremities; 21 were in the pelvic bones, 14 in the spine, and four in the scapula. Table i gives a synopsis of this material. In seven cases of osteosarcoma DSA was repeated (the total number of investigations was thus 14); in 14 other malignancies DSA was performed both prior to and after chemotherapy. In two cases it was performed prior to and after palliative embolization. During the first year, both large-frame analog arteriography and DSA were performed in one session in order to explore the efficacy of DSA in answering all those questions asked of museuloskeletal angiography.
Table 1. Synopsis of clinical survey (n = 140) Bone tumors Primary Benign (n = 14) • Osteoclastoma • Hemangioma • Osteochondroma • Osteoblastoma Malignant (n = 40) • Osteosarcoma • Ewing's sarcoma • Chondrosarcoma • Malignant fibrous histiocytoma • Bone retothelial sarcoma • Osteoclastoma (malignant)
8 4 1 1 17 11 5 3 3 1
Secondary Distant metastases
16
Tumor-like lesions of bones a
17
Soft-tissue tumors Benign Malignant Nontumorous conditions b
8 21 22
Operated, histologically uncertainly classified lesions
2
a Included are: 6 fibrous dysplasias; 3 solitary bone cysts; 3 aneurysmal bone cysts; 3 myositis ossificans pseudomaligna; 2 metaphyseal fibrous defects b Included are: 11 cases of osteomyelitis; 7 different expansions in soft tissues, subsequently confirmed as nontumorous (including one post-traumatic arterial aneurysm); I tuberculous ostitis; i angioneurodystrophy; 1 Paget's disease of bone; 1 neurotrophic arthropathy
90
J. Kolfi~et al.: DSA in orthopedic conditions
Results and discussion
Fig. 1. a Ewing's sarcoma of the right pubic bone (arrow). h Largeframe arteriography in the same patient (left: arterial; right: capillary phase). Displacement of arteries, pathological vascularization (arrows), and contrast stain with arteriovenous shunts (empty arrows) document the extent of the expansion into the small pelvis. c DSA in the same patient: accented tumorous stain with arteriovenous shunts
Our DSA unit works with a 9-in. image intensifier and is equipped with biplane 35 × 35 cm PUCK changers for rapid seriography as well. This installation enables free selection of either analog or digital investigation modes. For peripheral DSA, 5-10 ml of 60% Verografin (SPOFA) are given with a velocity of 10 ml/s via the femoral or brachial artery. Only once was the central venous route selected because of arterial obliteration in the investigated area. The results of both investigations were then evaluated independently by at least two radiologists. DSA is currently being used alone, except in some special cases that will be mentioned later.
Even in the era of CT and M R I , angiography continues to be of value as an important diagnostic tool in tumorous and tumor-like conditions of the bones and soft tissues [16]. M R I has already proved to have some particular advantages in these conditions [11, 13-15, 19]: it is noninvasive; it may exclude or confirm the involvement of both bone tissue and/or marrow by the tumor or inflammation; it excellently delineates the invasion of the tumor into the neighboring soft tissues and enables a differentiation between the tumorous tissues and surrounding edema; it differentiates the tumor from great vessels in its vicinity. Unfortunately, this method is not yet generally available for solving important orthopedic problems, as the n u m b e r of units is still limited and over 80% of their actual capacity is employed in solving neurological problems [5]. M R I was also not available for our register during this study. In contrast, CT is currently also being used for investigations of bone tumors and tumor-like conditions by our group. This noninvasive imaging modality provides important information about the invasion of the t u m o r into the soft tissues and/or medullary cavity of tubular bones and about the extent of bone destruction in anatomically complex skeletal parts and structures [13]; it is also a source of three-dimensional images. Nevertheless, CT cannot demonstrate the relations between the tumor and great vessels reliably enough and thus exclude their invasion, obturation and/or aneurysmal dilatation - all of which deserve the increased attention of orthopedic surgeons prior to their intervention or biopsy. CT also does not provide information about the vascularization of the lesions, which often helps in distinguishing between benign and malignant lesions prior to their histological classification [3]. F r o m musculoskeletal angiography a complex of important informations is expected [16, 20] including the vascularization of the condition (normal, increased, benign-malignant); the origin of nutritive vascular
J. Kolfi~ et al.: DSA in orthopedic conditions
91
Fig. 2. DSA of a soft-tissue expansion above the left knee; tortuous vessels and their feeding branches in this hemangioma are clearly visible branches; in the case of pathological vascularization the presence o f arteriovenous shunts, accelerated v e n o u s return, and/or aneurysms; relations b e t w e e n the t u m o r mass and the neighboring large vessels (their dislocation, invasion, obliteration, p s e u d o a n e u r y s m s ) . D S A has definitely p r o v e d to be time- and cost-efficient and safe, c o m p a r e d with hyperselective angiographic catheterization procedures. It also decreases the v o l u m e of contrast agent necessary for vascular opacification. Its reliability e x c e e d e d 85% in o u r survey. Subsequent case reports will serve as examples.
Case 1 A 17-year-old boy had had fever and a painful right knee for 2 months. Permeative destruction of his right pubic bone was found on plain roentgenograms, with suspicion of Ewing's sarcoma (Fig. la). Standard angiography (Fig. l b) illustrated extensive pathological vascularization originating from the right internal iliac artery, with inhomogeneous staining of a large tumorous mass displacing the urinary bladder. DSA (Fig. lc) documents these changes and, in a more impressive way, the abundance of arteriovenous shunts. Ewing's sarcoma was confirmed by biopsy. The patient was treated with combined chemotherapy and radiation. T h e excellent i n f o r m a t i o n afforded by arteriography in vascular t u m o r s [2, 4, 20] are also w a r r a n t e d by D S A :
Case 2 A 17-year-old girl had injured her left knee at the age of 9 years. Hemarthrosis had been evacuated twice by puncture. Later,
Fig.3.a Rounded expansion with a shell-like calcification in the soft parts of the right thigh (left) and its arteriographic picture (right). Simple dislocation of surrounding vessels without any pathological vascularization, b DSA in the same patient documents better the absence of pathological vascularization and the diffuse stain in this case of myositis ossificans pseudomaligna gradual enlargement of the upper calf developed with dilated superficial veins, without bone pathology on plain radiographs. Phleboliths were missing. DSA (Fig. 2) revealed an arteriovenous malformation with a broad arterial feeding branch and contrast staining of a rich venous network within the soft-tissue mass. The dynamics of filling and emptying of vessels was very impressive on display of the examination course. DSA helped in proper planning of surgical intervention, which was successful. Hemangioma was confirmed histologically. O f particular i m p o r t a n c e is the ability of D S A to "extract" the network of contrasted vessels f r o m dense (e.g., hyperostotic or sclerotic) b a c k g r o u n d s . This specific advantage was repeatedly p o i n t e d out in osteoid o s t e o m a s and osteoblastomas, for instance [6, 8, 10]. The nidus of an osteoid o s t e o m a can be localized by CT. Its fine contrast stain remains invisible on analog arteriograms due to superposition of dense shadows in its vicinity.
92 Serious problems also arise in myositis ossificans pseudomaligna, which is often believed by less experienced clinicians to be a soft-tissue malignancy; sometimes it is not even distinguishable from it. Calcifications of this pseudotumoral mass are very often misinterpreted on analog arteriograms as contrasted pathological venous lacunae. This false evaluation supports a suspicion fo malignancy. By subtraction of calcic shadows, DSA reveals the characteristic shell of regular vessels around the mass with no signs of malignant vascularization:
Case 3 A 27-year-old woman had a palpable mass in the lateral aspect of her right thigh. A rounded, shell-like shadow was seen on plain
J. Kolfif et al.: DSA in orthopedic conditions roentgenograms (Fig. 3a). The lesion was preliminary considered by us to be myositis ossificans pseudomaligna. A regular hypervascular shell without a malignant pattern was confirmed by DSA (Fig. 3b). Standard angiography could not exclude malignant vascularization due to summation of contrasted vessels with the calcifications within the mass.
Case 4 A 20-year-old woman noticed a painful swelling of her right thigh; Ewing's sarcoma was diagnosed elsewhere. She was referred with this diagnosis to our Register for therapy. From plain radiographs (Fig. 4a) no definite conclusion could be drawn about the nature of this condition. Both Ewing's sarcoma and osteomyelitis were taken into consideration. The lesion was thermographically very hyperemissive. Tiny, hyperemic vessels on analog angiograms did not exclude malignant hypervascularization definitely, due to overshadowing by sclerotic bone and periosteal appositions. DSA, on the contrary (Fig. 4b), demonstrated a shell-like formation of tortuous, hyperemic vessels, without any symptoms of malignancy. Biopsy confirmed osteomyelitis. Intensive antibiotic therapy was successful within several weeks.
In our survey, and in accordance with other reports [1, 7, 12], the visualization of tumoral staining and small vessels is definitely improved by DSA. DSA also enables control runs during embolization therapy and repeated controls prior to and after chemotherapy or radiation [6, 17], with lower discomfort for the patient and for the staff of the X-ray department as well. The low invasiveness of DSA enables arteriographical investigations also in patients who would be at high risk for Seldinger's catheterization (e.g., old and arteriosclerotic, severely ill persons). Continuous-mode display allows evaluation of investigations immediately after they are finished. A thorough evaluation of the blood flow and the character of the contrast-filled vessels is thus possible. The field of the image intensifier limits somewhat the actual area of visualization, when compared with standard 35 × 35 cm analog angiograms; this was never a serious disadvantage in our survey at all. Biplane investigations, when necessary, can easily be done in DSA after setting the changed position of the tube and with a repeated bolus injection of contrast material. Good cooperation of the patient is mandatory for a DSA investigation: even small movements during the run should be avoided, as they can compromise the results. The reading of DSA pictures is slightly uncommon
Fig. 4. a Native picture (left) and arteriogram (right) of chronic femoral osteomyelitis. Vascular pattern is hidden by osteosclerosis and periosteal appositions, b DSA of the same patient documents the absence of pathological vascularization and the increased stain within the periosteal shell
J. Kolfif"et al.: DSA in orthopedic conditions to less experienced clinicians, who miss the orientation, due to absence of subtracted b o n e shadows. This transient difficulty is easily overcome by the possibility of repeated evaluations of the runs f r o m the m e m o r y . Analog biplane arteriography is still preferred in our practice in patients considered for extensive limb-saving resections of malignant tumors, due to its still higher resolution of fine marginal vascular details. Individually, previous D S A m a y help in these cases as well, in setting a correct seriographic timing, according to the alreadyknown velocity of the blood flow. Conclusions
Angiography, irrespective of whether analog or digital, cannot replace the histological identification of the nature of the investigated tumorous or tumor-like condition, which is mandatory. With CT available, arteriography has recently fallen into decline in m a n y hospitals because of its invasiveness. This decline is often unjustifiable, as it does not respect the objective contributions of this m e t h o d at all, or the modern, safe m e t h o d offered by D S A [16]. CT cannot replace arteriography, as it cannot document the vascular relations properly. D S A not only enables this, but also improves the visualization of vessels in anatomically complex or overshadowed areas. This warrants a m o r e accurate evaluation of the character and extent of tumorous contrast stain and limits the risk of presence of an aneurysm or involvement of other important vessels which m a y be, if unrecognized, a serious complication during operative or bioptic interventions. D S A is also quite sufficient for recognition of nourishing vascular branches in malignant lesions for their ligation, catheterization in local chemotherapy, or palliative embolization. In addition, D S A reduces the discomfort and the total radiation impact during repeated controls done after therapeutic interventions. These controls help to evaluate m o r e precisely the prognosis and/or need for additive therapy. With all these positive factors, D S A remains the diagnostic m e t h o d of choice, but it m a y possibly be replaced by further developments and general availability of M R imaging. References
1. Arlart IP, Mark J, Bahren W (1984) Arterielle DSA bei malignen hypervaskularisierten Knochentumoren. Fortschr Rontgenstr 141 : 541-544
93 2. Becker H, Vogels H (1984) Digitale Subtraktionsangiographie zum Nachweis spinaler Angiome. Fortschr Rontgenstr 140: 686-689 3. Boijsen E, Ekelund L (eds) (1983) Computed tomography in orthopaedic radiology. Thieme, Stuttgart, pp 49-59 4. Crone-M~nzenbrock W, Baake S, Thoma S (1985) Comparison of CT and DSA for preoperative evaluation of soft tissue tumors of the extremities. Arch Orthop Trauma Surg 104: 319-324 5. Evens RG, Evens HG (1988) Economic and utilization analysis of MR imaging in the United States in 1987. Radiology 166 : 27-30 6. Gmelin E, Arlart IP (1987) Digitale Subtraktionsangiographie. Thieme, Stuttgart, pp 131-132 7. Goodman PC, Jeffrey RB, Brant-Zawadzki M (1984) DSA in extremity trauma. Radiology 153 : 61-64 8. Karnel F, Salomonovitz E, Gritzman N, Pongracz N (1986) DSA - eine wertvolle Methode zum Nachweis eines OsteoidOsteoms. Fortschr Rontgenstr 144: 735-736 9. Lee KR, Cox GG, Price HJ, Johnson JA, Neff RJ (1986) Intraarteriai DSA arteriographic evaluation of extremity tumors: comparison with conventional angiography. Radiology 158 : 255-258 10. Marshall JH, Sonshire JM (1987) Digital angiography and osteoblastoma of the triquetrum. J Hand Surg 12A: 256-258 11. Nyman R, Rehn S, Glimelius B (1987) MRI in diffuse malignant bone marrow disease. Acta Radiol 28 : 199-205 12. Paushter DM, Borkowski GP, Buonocore E (1983) Digital subtraction angiography for preoperative evaluation of extremity tumors. Am J Roentgenol 141 : 129-133 13. Pettersson H, Gillespy T (1987) Primary musculoskeletal tumors. Examination with MR imaging compared with conventional modalities. Radiology 164 : 237-242 14. Reiser M, Bohndorf K, et al (1987) Erste Erfahrungen mit GdDTPA in der Magnetischen Resonanztomographie von Knochen- und Weichteiltumoren. Radiologe 27 : 467-472 15. Reither M, Kaiser W, Imschweiler E (1987) Bedeutung der Kernspintomographie fiir die Diagnostik der Knochenmarkserkrankungen im Kindesalter. Fortschr Rontgenstr 147:647653 16. Sellier N, Vecchierini A, Kalifa G (1988) Tumeurs osseuses malignes de l'enfant. Reste-t-il one place pour l'art4riographie? J Radiol 69 : 7-12 17. Simonetti G, Passariello R, Rossi P (1985) Digital angiography in evaluation of orthopaedic tumors. Cardiovasc Intervent Radiol 8 : 83-88 18. Starck E, Harth P, Kollath J, Riemann H, Tuengerthal S, Walter M (1984) Klinische Erfahrungen mit der digitalen Subtraktionsangiographie. In: Baert AL, Boijsen E, Fuchs WA, Heuck FH (eds) Frontiers in European radiology. Springer, Berlin Heidelberg New York, pp 29-52 19. Vanel D, Lacombe MJ (1987) Musculoskeletal tumors. Follow-up with MR imaging after treatment with surgery and radiation therapy. Radiology 164 : 243-246 20. Yaghmai I (1979) Angiography of bone and soft tissue lesions. Springer, Berlin Heidelberg New York, pp 4-10, pp 231-285
°fOrthopaedic andTraumaSurgery © Springer-Verlag 1990
Digital subtraction angiography in musculoskeletal tumors and other conditions J. Kold~ 1, H. Zidkovd I, J. Sprindrich 1, and Z. Mat~jovsk~ 2 1Clinic for Diagnostic Radiology and 2Clinic for Orthopedic Surgery, Institute for Further Education of Physicians and Pharmacists, Prague, Czechoslovakia
Summary. O n e h u n d r e d and forty consecutive D S A examinations of various musculoskeletal diseases were analyzed with respect to the contributions and/or limits of this m o d e r n diagnostic imaging modality. A n g i o g r a phy remains the imaging tool of choice for m a n y benign and malignant o r t h o p e d i c conditions of b o n e s and soft tissues, mainly w h e n M R I is still not generally available. It remains indispensable for embolization and/or local c h e m o t h e r a p y . D S A has the advantage of being less invasive and it also surpasses analog a r t e r i o g r a p h y in better visualization of vascular patterns h i d d e n in hyperostosis, sclerosis, and metallic shadows. A n g i o g r a p h i c investigations, w h e n necessary, should therefore start with DSA.
Articles about digital subtraction a n g i o g r a p h y ( D S A ) in the world's medical literature emphasize its undisputed advantages and merits in cardiovascular diagnostics [6, 18]. F o r o r t h o p e d i c problems, the effectiveness of D S A has g o n e grossly unnoticed, with only a few exceptions [1, 4, 8, 10, 12, 17], reporting often on limited personal experience with individual observations or on certain types of lesions only. S o m e specialists still believe that the resolution capacity of D S A for small and pathological vessels is inferior, a l t h o u g h the m o d e r n generations of D S A satisfactorily solve this initial p r o b l e m [2, 7, 9]. In the Clinic for Diagnostic R a d i o l o g y I L F in Prague, a D S A unit has b e e n used for the P r a g u e B o n e T u m o r Register during the past years. T h e aim of this p a p e r is to evaluate o u r experiences with this imaging m o d a l i t y in o r t h o p e d i c problems, mainly with respect to t u m o r o u s and tumor-like conditions of the musculoskeletal system.
Clinical survey and method One hundred and forty consecutive patients indicated for pre- or postoperative angiography are considered in this survey. The na-
Offprint requests to: Prof. MUDr Jaromfr Kolfif- DrSc, Clinic for Diagnostic Radiology ILF Budfnova 2, 18081 Prague 8-Bulovka, Czechoslovakia
ture of their diseases was subsequently verified histologically. The overwhelming majority of lesions (101) were found in the extremities; 21 were in the pelvic bones, 14 in the spine, and four in the scapula. Table i gives a synopsis of this material. In seven cases of osteosarcoma DSA was repeated (the total number of investigations was thus 14); in 14 other malignancies DSA was performed both prior to and after chemotherapy. In two cases it was performed prior to and after palliative embolization. During the first year, both large-frame analog arteriography and DSA were performed in one session in order to explore the efficacy of DSA in answering all those questions asked of museuloskeletal angiography.
Table 1. Synopsis of clinical survey (n = 140) Bone tumors Primary Benign (n = 14) • Osteoclastoma • Hemangioma • Osteochondroma • Osteoblastoma Malignant (n = 40) • Osteosarcoma • Ewing's sarcoma • Chondrosarcoma • Malignant fibrous histiocytoma • Bone retothelial sarcoma • Osteoclastoma (malignant)
8 4 1 1 17 11 5 3 3 1
Secondary Distant metastases
16
Tumor-like lesions of bones a
17
Soft-tissue tumors Benign Malignant Nontumorous conditions b
8 21 22
Operated, histologically uncertainly classified lesions
2
a Included are: 6 fibrous dysplasias; 3 solitary bone cysts; 3 aneurysmal bone cysts; 3 myositis ossificans pseudomaligna; 2 metaphyseal fibrous defects b Included are: 11 cases of osteomyelitis; 7 different expansions in soft tissues, subsequently confirmed as nontumorous (including one post-traumatic arterial aneurysm); I tuberculous ostitis; i angioneurodystrophy; 1 Paget's disease of bone; 1 neurotrophic arthropathy
90
J. Kolfi~et al.: DSA in orthopedic conditions
Results and discussion
Fig. 1. a Ewing's sarcoma of the right pubic bone (arrow). h Largeframe arteriography in the same patient (left: arterial; right: capillary phase). Displacement of arteries, pathological vascularization (arrows), and contrast stain with arteriovenous shunts (empty arrows) document the extent of the expansion into the small pelvis. c DSA in the same patient: accented tumorous stain with arteriovenous shunts
Our DSA unit works with a 9-in. image intensifier and is equipped with biplane 35 × 35 cm PUCK changers for rapid seriography as well. This installation enables free selection of either analog or digital investigation modes. For peripheral DSA, 5-10 ml of 60% Verografin (SPOFA) are given with a velocity of 10 ml/s via the femoral or brachial artery. Only once was the central venous route selected because of arterial obliteration in the investigated area. The results of both investigations were then evaluated independently by at least two radiologists. DSA is currently being used alone, except in some special cases that will be mentioned later.
Even in the era of CT and M R I , angiography continues to be of value as an important diagnostic tool in tumorous and tumor-like conditions of the bones and soft tissues [16]. M R I has already proved to have some particular advantages in these conditions [11, 13-15, 19]: it is noninvasive; it may exclude or confirm the involvement of both bone tissue and/or marrow by the tumor or inflammation; it excellently delineates the invasion of the tumor into the neighboring soft tissues and enables a differentiation between the tumorous tissues and surrounding edema; it differentiates the tumor from great vessels in its vicinity. Unfortunately, this method is not yet generally available for solving important orthopedic problems, as the n u m b e r of units is still limited and over 80% of their actual capacity is employed in solving neurological problems [5]. M R I was also not available for our register during this study. In contrast, CT is currently also being used for investigations of bone tumors and tumor-like conditions by our group. This noninvasive imaging modality provides important information about the invasion of the t u m o r into the soft tissues and/or medullary cavity of tubular bones and about the extent of bone destruction in anatomically complex skeletal parts and structures [13]; it is also a source of three-dimensional images. Nevertheless, CT cannot demonstrate the relations between the tumor and great vessels reliably enough and thus exclude their invasion, obturation and/or aneurysmal dilatation - all of which deserve the increased attention of orthopedic surgeons prior to their intervention or biopsy. CT also does not provide information about the vascularization of the lesions, which often helps in distinguishing between benign and malignant lesions prior to their histological classification [3]. F r o m musculoskeletal angiography a complex of important informations is expected [16, 20] including the vascularization of the condition (normal, increased, benign-malignant); the origin of nutritive vascular
J. Kolfi~ et al.: DSA in orthopedic conditions
91
Fig. 2. DSA of a soft-tissue expansion above the left knee; tortuous vessels and their feeding branches in this hemangioma are clearly visible branches; in the case of pathological vascularization the presence o f arteriovenous shunts, accelerated v e n o u s return, and/or aneurysms; relations b e t w e e n the t u m o r mass and the neighboring large vessels (their dislocation, invasion, obliteration, p s e u d o a n e u r y s m s ) . D S A has definitely p r o v e d to be time- and cost-efficient and safe, c o m p a r e d with hyperselective angiographic catheterization procedures. It also decreases the v o l u m e of contrast agent necessary for vascular opacification. Its reliability e x c e e d e d 85% in o u r survey. Subsequent case reports will serve as examples.
Case 1 A 17-year-old boy had had fever and a painful right knee for 2 months. Permeative destruction of his right pubic bone was found on plain roentgenograms, with suspicion of Ewing's sarcoma (Fig. la). Standard angiography (Fig. l b) illustrated extensive pathological vascularization originating from the right internal iliac artery, with inhomogeneous staining of a large tumorous mass displacing the urinary bladder. DSA (Fig. lc) documents these changes and, in a more impressive way, the abundance of arteriovenous shunts. Ewing's sarcoma was confirmed by biopsy. The patient was treated with combined chemotherapy and radiation. T h e excellent i n f o r m a t i o n afforded by arteriography in vascular t u m o r s [2, 4, 20] are also w a r r a n t e d by D S A :
Case 2 A 17-year-old girl had injured her left knee at the age of 9 years. Hemarthrosis had been evacuated twice by puncture. Later,
Fig.3.a Rounded expansion with a shell-like calcification in the soft parts of the right thigh (left) and its arteriographic picture (right). Simple dislocation of surrounding vessels without any pathological vascularization, b DSA in the same patient documents better the absence of pathological vascularization and the diffuse stain in this case of myositis ossificans pseudomaligna gradual enlargement of the upper calf developed with dilated superficial veins, without bone pathology on plain radiographs. Phleboliths were missing. DSA (Fig. 2) revealed an arteriovenous malformation with a broad arterial feeding branch and contrast staining of a rich venous network within the soft-tissue mass. The dynamics of filling and emptying of vessels was very impressive on display of the examination course. DSA helped in proper planning of surgical intervention, which was successful. Hemangioma was confirmed histologically. O f particular i m p o r t a n c e is the ability of D S A to "extract" the network of contrasted vessels f r o m dense (e.g., hyperostotic or sclerotic) b a c k g r o u n d s . This specific advantage was repeatedly p o i n t e d out in osteoid o s t e o m a s and osteoblastomas, for instance [6, 8, 10]. The nidus of an osteoid o s t e o m a can be localized by CT. Its fine contrast stain remains invisible on analog arteriograms due to superposition of dense shadows in its vicinity.
92 Serious problems also arise in myositis ossificans pseudomaligna, which is often believed by less experienced clinicians to be a soft-tissue malignancy; sometimes it is not even distinguishable from it. Calcifications of this pseudotumoral mass are very often misinterpreted on analog arteriograms as contrasted pathological venous lacunae. This false evaluation supports a suspicion fo malignancy. By subtraction of calcic shadows, DSA reveals the characteristic shell of regular vessels around the mass with no signs of malignant vascularization:
Case 3 A 27-year-old woman had a palpable mass in the lateral aspect of her right thigh. A rounded, shell-like shadow was seen on plain
J. Kolfif et al.: DSA in orthopedic conditions roentgenograms (Fig. 3a). The lesion was preliminary considered by us to be myositis ossificans pseudomaligna. A regular hypervascular shell without a malignant pattern was confirmed by DSA (Fig. 3b). Standard angiography could not exclude malignant vascularization due to summation of contrasted vessels with the calcifications within the mass.
Case 4 A 20-year-old woman noticed a painful swelling of her right thigh; Ewing's sarcoma was diagnosed elsewhere. She was referred with this diagnosis to our Register for therapy. From plain radiographs (Fig. 4a) no definite conclusion could be drawn about the nature of this condition. Both Ewing's sarcoma and osteomyelitis were taken into consideration. The lesion was thermographically very hyperemissive. Tiny, hyperemic vessels on analog angiograms did not exclude malignant hypervascularization definitely, due to overshadowing by sclerotic bone and periosteal appositions. DSA, on the contrary (Fig. 4b), demonstrated a shell-like formation of tortuous, hyperemic vessels, without any symptoms of malignancy. Biopsy confirmed osteomyelitis. Intensive antibiotic therapy was successful within several weeks.
In our survey, and in accordance with other reports [1, 7, 12], the visualization of tumoral staining and small vessels is definitely improved by DSA. DSA also enables control runs during embolization therapy and repeated controls prior to and after chemotherapy or radiation [6, 17], with lower discomfort for the patient and for the staff of the X-ray department as well. The low invasiveness of DSA enables arteriographical investigations also in patients who would be at high risk for Seldinger's catheterization (e.g., old and arteriosclerotic, severely ill persons). Continuous-mode display allows evaluation of investigations immediately after they are finished. A thorough evaluation of the blood flow and the character of the contrast-filled vessels is thus possible. The field of the image intensifier limits somewhat the actual area of visualization, when compared with standard 35 × 35 cm analog angiograms; this was never a serious disadvantage in our survey at all. Biplane investigations, when necessary, can easily be done in DSA after setting the changed position of the tube and with a repeated bolus injection of contrast material. Good cooperation of the patient is mandatory for a DSA investigation: even small movements during the run should be avoided, as they can compromise the results. The reading of DSA pictures is slightly uncommon
Fig. 4. a Native picture (left) and arteriogram (right) of chronic femoral osteomyelitis. Vascular pattern is hidden by osteosclerosis and periosteal appositions, b DSA of the same patient documents the absence of pathological vascularization and the increased stain within the periosteal shell
J. Kolfif"et al.: DSA in orthopedic conditions to less experienced clinicians, who miss the orientation, due to absence of subtracted b o n e shadows. This transient difficulty is easily overcome by the possibility of repeated evaluations of the runs f r o m the m e m o r y . Analog biplane arteriography is still preferred in our practice in patients considered for extensive limb-saving resections of malignant tumors, due to its still higher resolution of fine marginal vascular details. Individually, previous D S A m a y help in these cases as well, in setting a correct seriographic timing, according to the alreadyknown velocity of the blood flow. Conclusions
Angiography, irrespective of whether analog or digital, cannot replace the histological identification of the nature of the investigated tumorous or tumor-like condition, which is mandatory. With CT available, arteriography has recently fallen into decline in m a n y hospitals because of its invasiveness. This decline is often unjustifiable, as it does not respect the objective contributions of this m e t h o d at all, or the modern, safe m e t h o d offered by D S A [16]. CT cannot replace arteriography, as it cannot document the vascular relations properly. D S A not only enables this, but also improves the visualization of vessels in anatomically complex or overshadowed areas. This warrants a m o r e accurate evaluation of the character and extent of tumorous contrast stain and limits the risk of presence of an aneurysm or involvement of other important vessels which m a y be, if unrecognized, a serious complication during operative or bioptic interventions. D S A is also quite sufficient for recognition of nourishing vascular branches in malignant lesions for their ligation, catheterization in local chemotherapy, or palliative embolization. In addition, D S A reduces the discomfort and the total radiation impact during repeated controls done after therapeutic interventions. These controls help to evaluate m o r e precisely the prognosis and/or need for additive therapy. With all these positive factors, D S A remains the diagnostic m e t h o d of choice, but it m a y possibly be replaced by further developments and general availability of M R imaging. References
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