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Intravenous contrast in spinal computed tomography to identify epidural metastases
Intravenous contrast in spinal computed tomography to identify epidural metastases W. Boogerd*, R. Kr6ger**
Introduction Summary Suspicion on a spinal epidural metastasis requires an emergency identification of the epidural lesion to ensure a rapid and accurate treatment to prevent further and usually irreversible loss of neurological function. Myelography is the diagnostic m e t h o d of choice 1'2. When intrathecal contrast injection is contraindicated, the treatment has to be based on information from non-invasive methods. Assessment of the clinical data with plain films and bone scan will inadequately predict the level and extent of the epidural lesion in about one third of the patients 1. Magnetic Resonance Imaging ( M R I ) is m o r e sensitive than plain spine films and bone scan in detecting osseous vertebral metastases and can show extension of the t u m o r mass into the spinal canal 3, but c o m p a r e d with myelography M R I m a y be less sensitive in detecting epidural metastases 2. Also spinal CT scanning is a m o r e sensitive diagnostic method than plain films, t o m o g r a p h y and bone scan for identifying vertebral metastases 4. H o w e v e r , intrathecal contrast administration is considered essential for the demonstration of epidural metastases 1,5,6. In this study we show that epidural metastases can clearly be demonstrated by the use of I V contrast in spinal CT scanning, without having to resort to the invasive method of myelography.
In 16 patients with spinal epidural metastases from various neoplasms the usefulness of intravenous (IV) contrast injection in spinal computed tomography (CT) scanning was analyzed for determining the presence and extent of the epidural lesion. In all cases enhancement of the epidural tumor mass occurred, which effectively showed the outline of the lesion. The extent of the epidural metastases in the spinal canal was equally well visualized as by myelography. Compared to spinal CT scanning without contrast administration, all IV contrast enhanced CT scans were clearly superior in demonstrating epidural metastases. Intravenous contrast in spinal CT-scanning appears to add relevant information and seems a useful and simple method to define the extent of the epidural tumor. It should be considered in patients where myelography is contraindicated and it may be a valuable method when the response of the epidural tumor to treatment must be determined. Key words: spinal computed tomography, intravenous contrast, epidural metastasis.
Patients and Methods Spinal C T scans were p e r f o r m e d after I V contrast injection in 16 patients with various types of cancer (table 1). Intravenous contrast was administered by bolus injection of 60 cc Telebrix
Departments of Neurology* and Radiology* * of the Netherlands Cancer Institute (Antoni van Leeuwenhoekhuis), Amsterdam. Address for correspondence and reprint requests: W. Boogerd, Antoni van Leeuwenhoekhuis, Plesmanlaan 121, 1066 C X Amsterdam, the Netherlands. Accepted 14.11.90 Clin Neurol Neurosurg 1991. Vol. 93-3
195
Table 1. Results of diagnostic m e t h o d s in patients with epidural metastases
Case 1 2 3 4 5 6
7 8 9 10 11 12 13 14 15 16
Primary Tumor
plain film*
Myelogram+
spinal C T scan + without with IV contrast contrast
Lymphoma Ewing's Sarc. A d e n o i d cystic carcinoma Breast Breast Undifferentiated carc. (prim u n k n o w n ) Breast Lymphoma Lymphoma Breast Breast Lymphoma A d e n o c a . lung Breast U n k n o w n prim. Lymphoma
Scl Scl +
+ + ND
ND + Dub
+ + +
+ + Scl
+ + +
Dub ND ND
+ + +
+ Scl + + Scl Scl + -
+ + + + + + + ND ND ND
Dub Dub ND Dub Dub +
+ + + + + + + + + +
+ ND +
*: A t the level of the epidural tumor; +: bone metastasis; Scl: sclerosis; -: normal ++: epidural tumor; ND: not done; Dub: d u b i o u s ; - : normal; IV: intravenous.
38 (Guerbet, France), followed by fast drip infusion of 250 cc Telebrix 12 which amounts to a total iodine content of 52.8 gram. Thirteen patients were clinically suspected of having spinal epidural metastasis. In the other 3 patients axial CT scans after IV contrast injection were performed because of a suspected mediastinal mass. In these patients the epidural mass was a coincidental finding. Repeat CT scans after IV contrast were made in 2 patients (pat. 4 and 7) for evaluation of the response to treatment of the epidural metastasis. Unenhanced spinal CT scans were made in 11 patients before IV contrast injection. Myelography was performed in 12 of the 16 patients. In case of complete epidural block a cisternal myelogram was added to identify the upper level of the block. Myelography had not been carfled out in 4 patients: in one patient (pat. 16) because of severe thrombocytopenia, and in another (pat. 14) because cervical myelography was considered too dangerous because of serious cervical instability as a result of widespread osteolytic metastases. Myelography was omitted in 2 patients (pat. 3 and 15) because the 196
contrast-enhanced CT scan was considered to provide adequate information. Plain films of the spine had been made in all patients. Results
The results are listed in table 1. Unequivocal visual enhancement of the epidural metastasis after IV contrast was obtained in all patients delineating the tumor in the spinal canal. This visual impression was further confirmed by density measurements performed on CT scans before and after IV contrast in 10 patients. Epidural tumor showed an average density increase of 38 Hounsfield Units (HU) versus an increase of 8 HU of the spinal cord, thus leading to an average increase of 30 HU density difference between pathological structures and the spinal cord. The presence and extent of the epidural lesions were equally well demonstrated by IV contrast enhanced CT as by myelography. In the 2 patients where CT scans with IV contrast were repeated, the CT scans following treatment showed a disappearance of the epidural tumor mass (figure 1) which was further confirmed by
bone replaced by soft tissue tumor
ePidural tumor tension
compressed myelum
Figure 1. (Case 7) CT scan without intravenous contrast injection shows tumorous involvement of the body of vertebra T12. A previous myelogram showed a complete block at this level (A). After intravenous contrast enhancement the epidural extension of the tumor can be discerned easily (B and C). C-q"scan following systemic chemotherapy before (D) and after (E) intravenous contrast administration. Disappearance of the epidural tumor. Recalcification of the vertebral body T12. 197
myelography in both patients. The plain radiographs showed no abnormalities at the level of the epidural metastasis in 4 of the 16 patients. Three of these patients had metastatic lymphoma and one patient died of a stroke before the primary tumor could be diagnosed. The plain films showed focal sclerotic vertebrae in 5 patients. Evident osseous metastatic lesions at the level of the epidural tumor were noted in the remaining 7 patients. Unenhanced CT scans were also performed in 11 patients. In all these instances visualization of the epidural tumor was unequivocally improved after IV contrast administration. No epidural tumor could be identified on the unenhanced CT scan in one patient with a metastatic adenocarcinoma of the lung. In 6 other patients visualization of the epidural tumor was dubious on the unenhanced CT scans. Vertebral metastases at the level of the epidural tumor were demonstrated by CT scan in 13 of the 16 patients. Ten of these 13 patients showed a cortical disruption of the vertebral body into the spinal canal. Diffuse sclerosis was found extending into the vertebral cortex in 2 patients (pat. 8 and 13). Only a central vertebral lesion that did not penetrate into the cortex was found in one patient (pat. 12). Paravertebral tumor mass contiguously to the epidural tumor was found in 6 patients (pat. 1, 8, 9, 12, 15, 16), including the 3 patients without osseous lesions on CT scan. No paravertebral tumor nor osseous metastases were found at the level of one of the epidural lesions in one patient who had two separate epidural metastases (pat 16). Discussion
Myelography is the most accurate method to diagnose epidural metastases demonstrating the full extent of the epidural tumor mass. In additon, on myelography cerebrospinal fluid is obtained for the assessment of intradural metastases. However, myelography may be contraindicated in cancer patients, as in some of our patients: for instance, excessive bleeding tendency rather frequently occurs in cancer patients and osteolysis can destabilize the cervical spine making myelography a hazardous procedure. In these instances the diagnosis and choice of treatment must be based on non-invasive diag198
nostic methods. Because epidural metastases usually arise from osseous vertebral metastases, the level of radiotherapy is often based on clinical data, plain spine films and bone scan. It has however become clear that the tumor level is incorrectly predicted by these data in as much as one third of the patients 1. Spinal CT scanning and MRI are more sensitive and specific than plain films and bone scan in detecting vertebral metastases 3'4, while MRI can also identify epidural lesions over the entire length of the spinal canal 3. Apart from the poor availability of MRI, myeolography appeared more sensitive than MRI in detecting epidural metastases in a comparative study:. Further improvement of the accuracy of MRI to identify epidural metastases, however, may be expected by the use of intravenous contrast 7'8. Epidural tumor is usually poorly or not at all demonstrated by spinal CT scanning without contrast, although the finding of metastatic disruption of the bony cortex surrounding the spinal canal points to a high risk for occurrence of epidural metastases 9. Similar findings were demonstrated in the present study. Spinal CT scanning is used in combination with myelography for the imaging of epidural tumor. CT is recommended to define the extent of the epidural tumor mass in case of a nearly complete epidural block when an insufficient amount of contrast leaks past the block to visualize the upper level on myeolography1~ Further, it is also used to define the outline of the epidural and of the paravertebral tumor when surgical treatment is considered. The use of IV contrast in spinal CT scanning for diagnosing epidural tumor has only occasionally been reported TM. Thus, it is generally stated that for demonstrating epidural metastases CT scanning may only be helpful when intrathecal contrast is administered 1'5'6. In the present study with epidural metastases from carcinoma and lymphoma enhancement of the epidural mass after IV contrast injection was sufficient for a clear identification and demarcation of the epidural mass in every case. The marked enhancement of the epidural tumor tissue following IV contrast is explained by a combination of pooling of the contrast in the neoplastic bloodvessels and distribution to the extravascular space. It results in a clear contrast
with the structures in the spinal canal, i.e. the C S F and the spinal cord, that lie behind the b l o o d brain barrier and show no or only minimal e n h a n c e m e n t after I V contrast. N o significant difference was n o t e d in the d e g r e e of e n h a n c e m e n t b e t w e e n the various malignant epidural t u m o r s in the present study; a real j u d g e m e n t a b o u t this subject is, h o w e v e r not possible because the patient g r o u p s are too small. Given the p o o r correlation in s o m e patients b e t w e e n the clinically suspected level and the real site of the epidural t u m o r , it must be stressed that in case of any d o u b t the spinal canal should be scanned o v e r a m o r e extensive area than the clinically suspected level alone. This, h o w e v e r , is hardly a p r o b l e m with m o d e r n state of the art e q u i p m e n t : for example, scanning the entire thoracic vertebral c o l u m n with 10 m m increm e n t s will take a b o u t 5 to 10 minutes. A c c o r d ingly, I V contrast administration in spinal C T scanning is a valuable and rapid diagnostic m e t h o d for the d e m o n s t r a t i o n of epidural metastases w h e n m y e l o g r a p h y is contraindicated. In addition, in case of a c o m p l e t e spinal block demo n s t r a t e d by m y e l o g r a p h y , spinal C T scanning with intravenous contrast might, in certain circumstances be an alternative for a possibly haza r d o u s and discomfortable additional l u m b a r or cervical p u n c t u r e for the identification of the o t h e r b o r d e r of the spinal block. Finally, C T with I V contrast is also useful as a simple and rapid m e t h o d to evaluate the response of the epidural t u m o r to treatment.
References 1
Early detection and treatment of spinal epidural metastases: The role of myelography. Ann Neuro11986; 20:696-702.
2
H A G E N A U C, GROSH W, CURRIE M, WILEY RG. C o m p a r i -
RODICHOK LD, RUCKDESCHEL JC, HARPER GR, e t a l .
of spinal magnetic resonance imaging and myeiography in cancer patients. J Clin Oncol 1987; 5:1663-69. son 3
SARPEL S, SARPEL G, YU E, H Y D E R S, KAUFMAN B, HINDO
W, EZDINLIE. Early diagnosis of spinal - epidural metastasis by magnetic resonance imaging. Cancer 1987; 59:1112-6. REDMOND J, SPRING D, MUNDERLOH SH, G E O R G E CB, MANSOUR RP, VOLK SA.
5
6
7
Spinal computed tomography
scanning in the evaluation of metastatic disease. Cancer 1984; 54:253-8. ZIMMERMANRA, BILANIUKLT. Imaging of tumors of the spinal canal and cord. Radiol Clin North Am 1988; 26:965-1007. DORWART RH, LA MASTERS DL, WATANABE TJ~ Tumors. In: Newton TH, Potts DG, eds. Computed tomography of the spine and spinal cord. San Anselmo: Clavadel Press, 1983; 115-47. STIMAC GK, PORTER BA , OLSON D A , GERLACH R, GENTON
M. Gadolinium - DTPA - enhanced MR imaging of spinal neoplasmus. A JR 1988; 151:1185-92. 8
9
10
11
ROTHWELL CI, JASPERS T, WORTHINGTON BS, HOLLAND
IM. Gadolinium - enhanced magnetic resonance imaging of spinal tumours. Br J Radiol 1989; 62: 1067-74. WEISSMAN DE, GILBERT M, WANG H, GROSSMAN SA. The use of computed tomography of the spine to identify patients at high risk for epidural metastases. J. Clin Oncol 1985; 1541-4. FINK IJ, GARRA BS, ZABELL A, DOPPMAN JL. Computed tomography with metrizamide myelography to define the extent of spinal canal block due to tumor. J Comput Assist Tomogr. 1984; 6:1072-5. PETTERSON H, HARWOOD - NASH DCF. C'I" and myelography of the spine and cord. Berlin: Springer, 1982.
199
Introduction Summary Suspicion on a spinal epidural metastasis requires an emergency identification of the epidural lesion to ensure a rapid and accurate treatment to prevent further and usually irreversible loss of neurological function. Myelography is the diagnostic m e t h o d of choice 1'2. When intrathecal contrast injection is contraindicated, the treatment has to be based on information from non-invasive methods. Assessment of the clinical data with plain films and bone scan will inadequately predict the level and extent of the epidural lesion in about one third of the patients 1. Magnetic Resonance Imaging ( M R I ) is m o r e sensitive than plain spine films and bone scan in detecting osseous vertebral metastases and can show extension of the t u m o r mass into the spinal canal 3, but c o m p a r e d with myelography M R I m a y be less sensitive in detecting epidural metastases 2. Also spinal CT scanning is a m o r e sensitive diagnostic method than plain films, t o m o g r a p h y and bone scan for identifying vertebral metastases 4. H o w e v e r , intrathecal contrast administration is considered essential for the demonstration of epidural metastases 1,5,6. In this study we show that epidural metastases can clearly be demonstrated by the use of I V contrast in spinal CT scanning, without having to resort to the invasive method of myelography.
In 16 patients with spinal epidural metastases from various neoplasms the usefulness of intravenous (IV) contrast injection in spinal computed tomography (CT) scanning was analyzed for determining the presence and extent of the epidural lesion. In all cases enhancement of the epidural tumor mass occurred, which effectively showed the outline of the lesion. The extent of the epidural metastases in the spinal canal was equally well visualized as by myelography. Compared to spinal CT scanning without contrast administration, all IV contrast enhanced CT scans were clearly superior in demonstrating epidural metastases. Intravenous contrast in spinal CT-scanning appears to add relevant information and seems a useful and simple method to define the extent of the epidural tumor. It should be considered in patients where myelography is contraindicated and it may be a valuable method when the response of the epidural tumor to treatment must be determined. Key words: spinal computed tomography, intravenous contrast, epidural metastasis.
Patients and Methods Spinal C T scans were p e r f o r m e d after I V contrast injection in 16 patients with various types of cancer (table 1). Intravenous contrast was administered by bolus injection of 60 cc Telebrix
Departments of Neurology* and Radiology* * of the Netherlands Cancer Institute (Antoni van Leeuwenhoekhuis), Amsterdam. Address for correspondence and reprint requests: W. Boogerd, Antoni van Leeuwenhoekhuis, Plesmanlaan 121, 1066 C X Amsterdam, the Netherlands. Accepted 14.11.90 Clin Neurol Neurosurg 1991. Vol. 93-3
195
Table 1. Results of diagnostic m e t h o d s in patients with epidural metastases
Case 1 2 3 4 5 6
7 8 9 10 11 12 13 14 15 16
Primary Tumor
plain film*
Myelogram+
spinal C T scan + without with IV contrast contrast
Lymphoma Ewing's Sarc. A d e n o i d cystic carcinoma Breast Breast Undifferentiated carc. (prim u n k n o w n ) Breast Lymphoma Lymphoma Breast Breast Lymphoma A d e n o c a . lung Breast U n k n o w n prim. Lymphoma
Scl Scl +
+ + ND
ND + Dub
+ + +
+ + Scl
+ + +
Dub ND ND
+ + +
+ Scl + + Scl Scl + -
+ + + + + + + ND ND ND
Dub Dub ND Dub Dub +
+ + + + + + + + + +
+ ND +
*: A t the level of the epidural tumor; +: bone metastasis; Scl: sclerosis; -: normal ++: epidural tumor; ND: not done; Dub: d u b i o u s ; - : normal; IV: intravenous.
38 (Guerbet, France), followed by fast drip infusion of 250 cc Telebrix 12 which amounts to a total iodine content of 52.8 gram. Thirteen patients were clinically suspected of having spinal epidural metastasis. In the other 3 patients axial CT scans after IV contrast injection were performed because of a suspected mediastinal mass. In these patients the epidural mass was a coincidental finding. Repeat CT scans after IV contrast were made in 2 patients (pat. 4 and 7) for evaluation of the response to treatment of the epidural metastasis. Unenhanced spinal CT scans were made in 11 patients before IV contrast injection. Myelography was performed in 12 of the 16 patients. In case of complete epidural block a cisternal myelogram was added to identify the upper level of the block. Myelography had not been carfled out in 4 patients: in one patient (pat. 16) because of severe thrombocytopenia, and in another (pat. 14) because cervical myelography was considered too dangerous because of serious cervical instability as a result of widespread osteolytic metastases. Myelography was omitted in 2 patients (pat. 3 and 15) because the 196
contrast-enhanced CT scan was considered to provide adequate information. Plain films of the spine had been made in all patients. Results
The results are listed in table 1. Unequivocal visual enhancement of the epidural metastasis after IV contrast was obtained in all patients delineating the tumor in the spinal canal. This visual impression was further confirmed by density measurements performed on CT scans before and after IV contrast in 10 patients. Epidural tumor showed an average density increase of 38 Hounsfield Units (HU) versus an increase of 8 HU of the spinal cord, thus leading to an average increase of 30 HU density difference between pathological structures and the spinal cord. The presence and extent of the epidural lesions were equally well demonstrated by IV contrast enhanced CT as by myelography. In the 2 patients where CT scans with IV contrast were repeated, the CT scans following treatment showed a disappearance of the epidural tumor mass (figure 1) which was further confirmed by
bone replaced by soft tissue tumor
ePidural tumor tension
compressed myelum
Figure 1. (Case 7) CT scan without intravenous contrast injection shows tumorous involvement of the body of vertebra T12. A previous myelogram showed a complete block at this level (A). After intravenous contrast enhancement the epidural extension of the tumor can be discerned easily (B and C). C-q"scan following systemic chemotherapy before (D) and after (E) intravenous contrast administration. Disappearance of the epidural tumor. Recalcification of the vertebral body T12. 197
myelography in both patients. The plain radiographs showed no abnormalities at the level of the epidural metastasis in 4 of the 16 patients. Three of these patients had metastatic lymphoma and one patient died of a stroke before the primary tumor could be diagnosed. The plain films showed focal sclerotic vertebrae in 5 patients. Evident osseous metastatic lesions at the level of the epidural tumor were noted in the remaining 7 patients. Unenhanced CT scans were also performed in 11 patients. In all these instances visualization of the epidural tumor was unequivocally improved after IV contrast administration. No epidural tumor could be identified on the unenhanced CT scan in one patient with a metastatic adenocarcinoma of the lung. In 6 other patients visualization of the epidural tumor was dubious on the unenhanced CT scans. Vertebral metastases at the level of the epidural tumor were demonstrated by CT scan in 13 of the 16 patients. Ten of these 13 patients showed a cortical disruption of the vertebral body into the spinal canal. Diffuse sclerosis was found extending into the vertebral cortex in 2 patients (pat. 8 and 13). Only a central vertebral lesion that did not penetrate into the cortex was found in one patient (pat. 12). Paravertebral tumor mass contiguously to the epidural tumor was found in 6 patients (pat. 1, 8, 9, 12, 15, 16), including the 3 patients without osseous lesions on CT scan. No paravertebral tumor nor osseous metastases were found at the level of one of the epidural lesions in one patient who had two separate epidural metastases (pat 16). Discussion
Myelography is the most accurate method to diagnose epidural metastases demonstrating the full extent of the epidural tumor mass. In additon, on myelography cerebrospinal fluid is obtained for the assessment of intradural metastases. However, myelography may be contraindicated in cancer patients, as in some of our patients: for instance, excessive bleeding tendency rather frequently occurs in cancer patients and osteolysis can destabilize the cervical spine making myelography a hazardous procedure. In these instances the diagnosis and choice of treatment must be based on non-invasive diag198
nostic methods. Because epidural metastases usually arise from osseous vertebral metastases, the level of radiotherapy is often based on clinical data, plain spine films and bone scan. It has however become clear that the tumor level is incorrectly predicted by these data in as much as one third of the patients 1. Spinal CT scanning and MRI are more sensitive and specific than plain films and bone scan in detecting vertebral metastases 3'4, while MRI can also identify epidural lesions over the entire length of the spinal canal 3. Apart from the poor availability of MRI, myeolography appeared more sensitive than MRI in detecting epidural metastases in a comparative study:. Further improvement of the accuracy of MRI to identify epidural metastases, however, may be expected by the use of intravenous contrast 7'8. Epidural tumor is usually poorly or not at all demonstrated by spinal CT scanning without contrast, although the finding of metastatic disruption of the bony cortex surrounding the spinal canal points to a high risk for occurrence of epidural metastases 9. Similar findings were demonstrated in the present study. Spinal CT scanning is used in combination with myelography for the imaging of epidural tumor. CT is recommended to define the extent of the epidural tumor mass in case of a nearly complete epidural block when an insufficient amount of contrast leaks past the block to visualize the upper level on myeolography1~ Further, it is also used to define the outline of the epidural and of the paravertebral tumor when surgical treatment is considered. The use of IV contrast in spinal CT scanning for diagnosing epidural tumor has only occasionally been reported TM. Thus, it is generally stated that for demonstrating epidural metastases CT scanning may only be helpful when intrathecal contrast is administered 1'5'6. In the present study with epidural metastases from carcinoma and lymphoma enhancement of the epidural mass after IV contrast injection was sufficient for a clear identification and demarcation of the epidural mass in every case. The marked enhancement of the epidural tumor tissue following IV contrast is explained by a combination of pooling of the contrast in the neoplastic bloodvessels and distribution to the extravascular space. It results in a clear contrast
with the structures in the spinal canal, i.e. the C S F and the spinal cord, that lie behind the b l o o d brain barrier and show no or only minimal e n h a n c e m e n t after I V contrast. N o significant difference was n o t e d in the d e g r e e of e n h a n c e m e n t b e t w e e n the various malignant epidural t u m o r s in the present study; a real j u d g e m e n t a b o u t this subject is, h o w e v e r not possible because the patient g r o u p s are too small. Given the p o o r correlation in s o m e patients b e t w e e n the clinically suspected level and the real site of the epidural t u m o r , it must be stressed that in case of any d o u b t the spinal canal should be scanned o v e r a m o r e extensive area than the clinically suspected level alone. This, h o w e v e r , is hardly a p r o b l e m with m o d e r n state of the art e q u i p m e n t : for example, scanning the entire thoracic vertebral c o l u m n with 10 m m increm e n t s will take a b o u t 5 to 10 minutes. A c c o r d ingly, I V contrast administration in spinal C T scanning is a valuable and rapid diagnostic m e t h o d for the d e m o n s t r a t i o n of epidural metastases w h e n m y e l o g r a p h y is contraindicated. In addition, in case of a c o m p l e t e spinal block demo n s t r a t e d by m y e l o g r a p h y , spinal C T scanning with intravenous contrast might, in certain circumstances be an alternative for a possibly haza r d o u s and discomfortable additional l u m b a r or cervical p u n c t u r e for the identification of the o t h e r b o r d e r of the spinal block. Finally, C T with I V contrast is also useful as a simple and rapid m e t h o d to evaluate the response of the epidural t u m o r to treatment.
References 1
Early detection and treatment of spinal epidural metastases: The role of myelography. Ann Neuro11986; 20:696-702.
2
H A G E N A U C, GROSH W, CURRIE M, WILEY RG. C o m p a r i -
RODICHOK LD, RUCKDESCHEL JC, HARPER GR, e t a l .
of spinal magnetic resonance imaging and myeiography in cancer patients. J Clin Oncol 1987; 5:1663-69. son 3
SARPEL S, SARPEL G, YU E, H Y D E R S, KAUFMAN B, HINDO
W, EZDINLIE. Early diagnosis of spinal - epidural metastasis by magnetic resonance imaging. Cancer 1987; 59:1112-6. REDMOND J, SPRING D, MUNDERLOH SH, G E O R G E CB, MANSOUR RP, VOLK SA.
5
6
7
Spinal computed tomography
scanning in the evaluation of metastatic disease. Cancer 1984; 54:253-8. ZIMMERMANRA, BILANIUKLT. Imaging of tumors of the spinal canal and cord. Radiol Clin North Am 1988; 26:965-1007. DORWART RH, LA MASTERS DL, WATANABE TJ~ Tumors. In: Newton TH, Potts DG, eds. Computed tomography of the spine and spinal cord. San Anselmo: Clavadel Press, 1983; 115-47. STIMAC GK, PORTER BA , OLSON D A , GERLACH R, GENTON
M. Gadolinium - DTPA - enhanced MR imaging of spinal neoplasmus. A JR 1988; 151:1185-92. 8
9
10
11
ROTHWELL CI, JASPERS T, WORTHINGTON BS, HOLLAND
IM. Gadolinium - enhanced magnetic resonance imaging of spinal tumours. Br J Radiol 1989; 62: 1067-74. WEISSMAN DE, GILBERT M, WANG H, GROSSMAN SA. The use of computed tomography of the spine to identify patients at high risk for epidural metastases. J. Clin Oncol 1985; 1541-4. FINK IJ, GARRA BS, ZABELL A, DOPPMAN JL. Computed tomography with metrizamide myelography to define the extent of spinal canal block due to tumor. J Comput Assist Tomogr. 1984; 6:1072-5. PETTERSON H, HARWOOD - NASH DCF. C'I" and myelography of the spine and cord. Berlin: Springer, 1982.
199