- Email: [email protected]
CT arteriography for orbital tumors: Diagnostic and surgical value
Journal of Clinical Neuroscience (2005) 12(5), 548–552 0967-5868/$ - see front matter ª 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jocn.2004.08.012
Clinical study
CT arteriography for orbital tumors: Diagnostic and surgical value Mitsuhiro Hasegawa1 MD PHD, Hironori Fujisawa1 MD, Yutaka Hayashi1 MD, Junkoh Yamashita1 MD, Masayuki Suzuki1 MD, Osamu Matsui2 MD 1 Department of Neurosurgery and 2Departments of Radiology, Division of Neuroscience, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
Summary The aim of this study is to investigate the efficacy of dynamic computed tomography (CT) during selective angiography (CTarteriography) of orbital tumors in the evaluation of intratumoral vascular anatomy, feeding artery territory, and histological diagnosis. Among 35 consecutive cases with various orbital lesions, those cases showing tumor staining or pooling of the contrast medium on digital subtraction angiography (DSA) were evaluated by CT-arteriography (n = 14). The information obtained by CT-arteriography was compared with that provided by enhanced MRI (n = 31) and dynamic MRI (n = 21), in which the contrast medium was injected intravenously. In addition to the visualization of fine vascular anatomy, CT-arteriography emphasized areas of nodular enhancement and non-enhancing cystic/necrotic components as well as the intratumoral feeding arteries. Patterns of CT-arteriography were categorized into three subgroups: homogeneous enhancement (benign lymphoid lesion), partial enhancement (schwannomas and carcinomas), and patchy multinodular enhancement (specific for cavernous angiomas). In addition, CT-arteriography with selective arterial catheterization clearly delineated the feeding artery territories. CT-arteriography, with a minimal dose of contrast medium, can offer significant advantages over intravenously injected dynamic neuroimaging, and provides additional valuable preoperative information about the orbital tumor under investigation. ª 2005 Elsevier Ltd. All rights reserved. Keywords: intra-arterial contrast medium, CT-arteriography, helical CT, orbital tumors, dynamic imaging
INTRODUCTION A large variety of tumors and non-tumorous lesions may develop in the orbital region.1 Thus, preoperative diagnosis is essential to determine the best therapeutic strategy. Therapy may range from periodic observation to extensive excision.2,3 In addition to conventional CT and MRI, dynamic studies with serial scans taken during the phase of rapid intravenous injection of contrast medium have been reported to be useful in the differential diagnosis of orbital lesions.4,5 In recent years, the angio-CT system (a combination of digital subtraction angiography (DSA) and CT scan facilities in one suite), incorporating multislice CT, has become increasingly popular. We have previously reported the usefulness of CT during selective angiography (CT-arteriography) as a less invasive diagnostic tool to determine the precise location and structure of several lesions, including spinal arteriovenous fistulas (AVF)6 and cerebral aneurysms.7 Data from CT-arteriography may provide more precise preoperative anatomical and pathological information for almost any type of lesion. In this report, we present CT-arteriography as a useful tool for the precise evaluation of the surgical anatomy and pathology of orbital lesions. PATIENTS AND METHODS From April 1996 to November 2003, a total of 35 patients with orbital lesions were referred to our department for surgery. Twenty Received 21 July 2004 Accepted 6 August 2004 Correspondence to: Mitsuhiro Hasegawa, Department of Neurosurgery, Division of Neuroscience, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan. Tel.: +81 76 265 2384; Fax: +81 76 234 4262; E-mail: [email protected]
548
patients were evaluated preoperatively using DSA. Among those patients, CT-arteriography was performed (n = 14) if tumor staining or venous pooling was seen on the DSA (Table 1). The method for CT-arteriography has been described elsewhere.6 In brief, scans were performed at the level of the orbit with helical images (3–5 mm collimation; 1.5–2.5 mm overlapping reconstruction; 5 mm/s table speed) in the IVR-CT/angio system, X-Active (Toshiba, Japan), which incorporates helical CT with a C arm and a sliding patient table. Following DSA, 6-fold-diluted contrast medium was administered intra-arterially at a rate of 2–2.5 ml/sec via a 5F-catheter positioned in the internal carotid or external carotid artery. The ideal concentration of the angiographic contrast medium during CT-arteriography was determined to obtain the optimal resolution of both artery and bone. The total scan length was different in each case and depended on the tumor size.
RESULTS There were 10 women and 4 men in this series aged between 33 and 64 years (mean 53). In all cases, histology was surgically verified. The CT-arteriographic findings are summarized in Table 1. The patterns of CT-arteriography were categorized into three subgroups: homogeneous enhancement, partial enhancement with a non-enhancing component, or patchy multinodular enhancement. Compared to the images obtained by dynamic MRI, CT-arteriography better demonstrated the nodular enhanced areas, intratumoral feeding arteries and non-enhancing cystic components. The patchy nodular contrast-enhancing pattern was specific for cavernous angioma (Fig. 1). The number of nodules revealed by CT-arteriography correlated with the number of feeding arteries found at surgery. Non-enhancing components were seen in schwannomas (Fig. 2) and carcinomas (Fig. 3), and indicated intratumoral cysts and necrosis, respectively. Many small vessels were visualized by CT-arteriography in meningiomas and benign lacrimal gland
CT arteriography for orbital tumors 549
Table 1 Case No. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Age/sex 46/F 54/F 63/M 33/M 52/M 58/F 46/F 46/F 62/F 60/F 64/F 61/F 57/F 41/M
Pathology
CT-arteriography
Dynamic MRI
cavernous angioma cavernous angioma metastasis from lung ca. orbital schwannoma malignant myoepithelioma bil B-cell lymphoma T cell lymphoma bil lacrimal gl lymphoid hyperplasia Wegener’s granulomatosis optic sheath meningioma meningioma meningioma lacrimal gl pleomorphic adenoma lacrimal gl carcinoma
patchy nodular patchy nodular partial partial with cyst partial with cyst homogeneous homogeneous homogeneous homogeneous homogeneous and vessels partial and vessels homogeneous and vessels partial homogeneous and vessels
nodular nodular homogeneous homogeneous with cyst heterogeneous with cyst not available homogeneous homogeneous not available homogeneous not available not available heterogeneous homogeneous
bil = bilateral, gl = gland.
Fig. 1 Cavernous angioma. Dynamic MRI (A, B) and CT-arteriography (C, D) in large (Case 1: A, C) and medium-sized (Case 2: B, D, E) cavernous angioma. A and B: serial axial dynamic MRI (approximately 20-second intervals each) showing patchy central or peripheral enhancement (A: case 1; B: case 2). C: serial axial CT-arteriographic images at the same level obtained 4, 8, and 28 seconds after injection into the internal carotid artery, showing two patchy nodules (Case 1). D: serial axial CT-arteriographic images obtained 4 and 8 seconds after injection into the internal carotid artery, showing two patchy nodules (one located near the retina, the second located mid-tumor), which were comparable to the feeding vessels found at surgery in (Case 2). E: intraoperative photograph. The arrow indicates the second feeding artery, which has been coagulated and divided and was defined in figure 1D.
tumors, which are difficult to differentiate on MRI. Defined vascular structures were found to correlate well with the operative findings (Figs. 4 and 5). The lymphoid lesions showed neither intratumoral feeding arteries nor heterogeneous enhancement (Fig. 6). ª 2005 Elsevier Ltd. All rights reserved.
As well as characteristic findings for various tumors, fine vascular anatomy can be defined using CT-arteriography, including the ophthalmic artery, lacrimal artery, anterior and posterior ethmoidal arteries, central retinal artery, superior ophthalmic vein, Journal of Clinical Neuroscience (2005) 12(5), 548–552
550 Hasegawa et al.
Fig. 2 Orbital schwannoma with multiple cystic components. A: dynamic MRI at the same level (approximately 20-second intervals) shows an irregularly shaped partially enhancing tumor, but the small intratumoral cyst is barely visible. B, C: axial (B: 12, 15 and 18 seconds after contrast material injection) and reconstructed sagittal (C) CT-arteriography showing a large retrobulbar (\) and small intratumoral cyst (arrow). The double arrow indicates the ophthalmic artery.
Fig. 3 Metastatic small cell lung carcinoma (A, B, C: Case 3) and primary orbital adenocarcinoma (D: Case 14). A: dynamic MRI showing a homogeneously enhancing intraorbital tumor with invasion of the lateral orbital wall and temporalis muscle. B, C: CT-arteriography obtained by injection into the external carotid artery (B) and internal carotid artery (C), showing well-demarcated feeding artery territories (*). Arrow: intratumoral necrosis. D: axial CT-arteriography showing external carotid supplied enhancing territory and intratumoral nonenhanced necrotic area (arrow).
and lacrimal vein (Figs. 2, 4, and 6). Extraocular muscles and retina enhance homogeneously. The relationship between the tumor and the vascular and other surrounding anatomical structures of importance was clearly depicted. Additionally, CT-arteriography clearly demonstrated the feeding artery territories from the external carotid or internal carotid arteries in meningiomas and malignant invasive tumors (Fig. 3). Thus detail cannot be obtained using intravenously injected contrast material. DISCUSSION
information obtained from angiography. In addition to bone and soft tissue anatomy, CT-arteriography appropriately reveals normal and pathological intraorbital fine vascular anatomy. An optic nerve engulfed and deviated by the lesion can be welldefined as less enhanced tissue. To maintain visual function during surgical resection of the tumor, not only the optic nerve but also the ophthalmic and central retinal arteries must be preserved. The information provided by CT-arteriography as to the exact location of and the relationship to the tumor mass, fine arteries and veins, external ocular muscles, and the optic nerve, as depicted in this study, is useful to allow safe manipulation of important structures.
Anatomy The orbital cavity contains adipose tissue, muscles, vessels, lacrimal and sebaceous glands, and branches of the cranial nerves. It is not always easy to define the location and relationship of tumor tissue to important surrounding normal structures using Journal of Clinical Neuroscience (2005) 12(5), 548–552
Imaging modalities CT-arteriography, which has been widely recognized as useful to examine the liver and other organs, has been introduced to neuroª 2005 Elsevier Ltd. All rights reserved.
CT arteriography for orbital tumors 551
Fig. 4 Optic sheath meningioma. A: axial dynamic MRI (approximately 20-second intervals) at the same level, showing a large retrobulbar homogeneously enhancing mass. B: DSA of the internal carotid artery shows retrobulbar tumor staining fed by ophthalmic artery (arrow). C: Axial CT-arteriography (3, 4, 5, and 8 seconds after injection), showing the lacrimal artery (arrow), posterolateral ciliary artery (double arrow), ophthalmic artery (crossed arrow), and intratumoral abnormal vessels. Note that the less-enhanced optic nerve (OPTN) embedded in enhancing tumor tissue is clearly visible. The origin of the ophthalmic artery is clearly seen (arrow with *).
Fig. 5 Dynamic images of orbital mixed lacrimal tumor. A: axial dynamic MRI at the same level, showing homogeneously enhancing lacrimal gland tumor (20-second intervals). B: Axial CT-arteriography at the same level (8 seconds after injection), showing heterogeneously enhancing tumor and intratumoral abnormal vessels. Arrow indicates enlarged lacrimal vein.
imaging.6,7,8 Compared with the widely established techniques of dynamic MRI5,9 or two-phase helical CT4 with intravenous contrast medium for orbital tumors, this method is less used. This may be due to the need for troublesome transport of catheterized patients from the DSA to the CT suite. However, since the introduction of DSA and multislice CT systems producing high-quality images using a single patient couch, CT-arteriography may become more popular orbital tumor surgery. Efficacy of CT-arteriography for orbit pathology Accurate preoperative lesion localization and diagnosis should be provided by modern neuroimaging techniques, including CT and MRI. Our correlation of CT-angiography findings and orbital lesion pathology is described above. One of the most specific findª 2005 Elsevier Ltd. All rights reserved.
ings was the patchy nodular contrast enhancement seen in cavernous angioma. Ohtsuka et al. reported the efficacy of dynamic MRI in 2 cases of orbital cavernous angioma, which also had a patchy appearance.5 Small angiomas show homogeneous enhancement.10 In our study, CT-arteriographic images of cavernous angioma were compared in detail with dynamic MRI images. CT-arteriography revealed multiple feeding vessels, barely demonstrable by DSA or conventional MRI. These results correlated with the operative findings of numerous, thin feeding arteries. CT-arteriography appears more accurate in visualizing such pathology. CT arteriography also clearly defined that component of the tumor fed by internal carotid artery from that fed by the external artery in cases of carcinoma and meningioma. This may be useful in estimating the effectiveness of preoperative embolization. Journal of Clinical Neuroscience (2005) 12(5), 548–552
552 Hasegawa et al.
Fig. 6 Lymphoid hyperplasia of the lacrimal gland. A: axial dynamic MRI showing homogeneous enhancement of the lacrimal gland. B and C: early (B) and late (C) phase CT-arteriography with injection of contrast into the internal carotid artery, showing normal vascular structure including ophthalmic (arrow) and central retinal (side by side arrows) arteries, and homogenous gland enhancement with small abnormal intratumoral vessels. D: CT-arteriography with injection of contrast into the external carotid artery, showing normal vascular structures, including the superior ophthalmic (arrow), lacrimal (side by side arrows) and medial temporal (double) veins, and homogeneous enhancement of the gland.
REFERENCES 1. Demirci H, Shields CL, Shields JA, Honavar SG, Mercado GJ, Tovilla JC. Orbital tumors in the older adult population. Ophthalmology 2002; 109: 243–248. 2. Maroon JC, Kennerdell JS, Abla A. The diagnosis and treatment of orbital tumors. Clin Neurosurg 1988; 34: 485–498. 3. Kang JK, Lee IW, Jeun SS et al. Tumors of the orbit. Pitfalls of the surgical approach in 37 children with orbital tumor. Childs Nerv Syst 1997; 13: 536–541. 4. Moon WJ, Na DG, Ryoo JW et al. Orbital lymphoma and subacute or chronic inflammatory pseudotumor: differentiation with two-phase helical computed tomography. J Comput Assist Tomogr 2003; 27: 510–516. 5. Ohtsuka K, Hashimoto M, Akiba H. Serial dynamic magnetic resonance imaging of orbital cavernous hemangioma. Am J Ophthalmol 1997; 123: 396–398.
Journal of Clinical Neuroscience (2005) 12(5), 548–552
6. Hasegawa M, Fujisawa H, Kawamura T, Yamashita J, Matsui O. The efficacy of CT arteriography for spinal arteriovenous fistula surgery: technical note. Neuroradiology 1999; 41: 915–919. 7. Nomura M, Kida S, Uchiyama N et al. CT during selective arteriography: anatomical assessment of unruptured intracranial aneurysms before endovascular treatment. Neuroradiology 2001; 43: 735–741. 8. Tomura N, Hashimoto M, Sashi R et al. Superselective angio-CT of brain tumors. AJNR Am J Neuroradiol 1996; 17: 1073–1080. 9. Shinaver CN, Mafee MF, Choi KH. MRI of mesenchymal chondrosarcoma of the orbit: case report and review of the literature. Neuroradiology 1997; 39: 296–301. 10. Thorn-Kany M, Arrue P, Delisle MB, Lacroix F, Lagarrigue J, Manelfe C. Cavernous hemangiomas of the orbit: MR imaging. J Neuroradiol 1999; 26: 79–86.
ª 2005 Elsevier Ltd. All rights reserved.
Clinical study
CT arteriography for orbital tumors: Diagnostic and surgical value Mitsuhiro Hasegawa1 MD PHD, Hironori Fujisawa1 MD, Yutaka Hayashi1 MD, Junkoh Yamashita1 MD, Masayuki Suzuki1 MD, Osamu Matsui2 MD 1 Department of Neurosurgery and 2Departments of Radiology, Division of Neuroscience, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
Summary The aim of this study is to investigate the efficacy of dynamic computed tomography (CT) during selective angiography (CTarteriography) of orbital tumors in the evaluation of intratumoral vascular anatomy, feeding artery territory, and histological diagnosis. Among 35 consecutive cases with various orbital lesions, those cases showing tumor staining or pooling of the contrast medium on digital subtraction angiography (DSA) were evaluated by CT-arteriography (n = 14). The information obtained by CT-arteriography was compared with that provided by enhanced MRI (n = 31) and dynamic MRI (n = 21), in which the contrast medium was injected intravenously. In addition to the visualization of fine vascular anatomy, CT-arteriography emphasized areas of nodular enhancement and non-enhancing cystic/necrotic components as well as the intratumoral feeding arteries. Patterns of CT-arteriography were categorized into three subgroups: homogeneous enhancement (benign lymphoid lesion), partial enhancement (schwannomas and carcinomas), and patchy multinodular enhancement (specific for cavernous angiomas). In addition, CT-arteriography with selective arterial catheterization clearly delineated the feeding artery territories. CT-arteriography, with a minimal dose of contrast medium, can offer significant advantages over intravenously injected dynamic neuroimaging, and provides additional valuable preoperative information about the orbital tumor under investigation. ª 2005 Elsevier Ltd. All rights reserved. Keywords: intra-arterial contrast medium, CT-arteriography, helical CT, orbital tumors, dynamic imaging
INTRODUCTION A large variety of tumors and non-tumorous lesions may develop in the orbital region.1 Thus, preoperative diagnosis is essential to determine the best therapeutic strategy. Therapy may range from periodic observation to extensive excision.2,3 In addition to conventional CT and MRI, dynamic studies with serial scans taken during the phase of rapid intravenous injection of contrast medium have been reported to be useful in the differential diagnosis of orbital lesions.4,5 In recent years, the angio-CT system (a combination of digital subtraction angiography (DSA) and CT scan facilities in one suite), incorporating multislice CT, has become increasingly popular. We have previously reported the usefulness of CT during selective angiography (CT-arteriography) as a less invasive diagnostic tool to determine the precise location and structure of several lesions, including spinal arteriovenous fistulas (AVF)6 and cerebral aneurysms.7 Data from CT-arteriography may provide more precise preoperative anatomical and pathological information for almost any type of lesion. In this report, we present CT-arteriography as a useful tool for the precise evaluation of the surgical anatomy and pathology of orbital lesions. PATIENTS AND METHODS From April 1996 to November 2003, a total of 35 patients with orbital lesions were referred to our department for surgery. Twenty Received 21 July 2004 Accepted 6 August 2004 Correspondence to: Mitsuhiro Hasegawa, Department of Neurosurgery, Division of Neuroscience, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, 920-8641, Japan. Tel.: +81 76 265 2384; Fax: +81 76 234 4262; E-mail: [email protected]
548
patients were evaluated preoperatively using DSA. Among those patients, CT-arteriography was performed (n = 14) if tumor staining or venous pooling was seen on the DSA (Table 1). The method for CT-arteriography has been described elsewhere.6 In brief, scans were performed at the level of the orbit with helical images (3–5 mm collimation; 1.5–2.5 mm overlapping reconstruction; 5 mm/s table speed) in the IVR-CT/angio system, X-Active (Toshiba, Japan), which incorporates helical CT with a C arm and a sliding patient table. Following DSA, 6-fold-diluted contrast medium was administered intra-arterially at a rate of 2–2.5 ml/sec via a 5F-catheter positioned in the internal carotid or external carotid artery. The ideal concentration of the angiographic contrast medium during CT-arteriography was determined to obtain the optimal resolution of both artery and bone. The total scan length was different in each case and depended on the tumor size.
RESULTS There were 10 women and 4 men in this series aged between 33 and 64 years (mean 53). In all cases, histology was surgically verified. The CT-arteriographic findings are summarized in Table 1. The patterns of CT-arteriography were categorized into three subgroups: homogeneous enhancement, partial enhancement with a non-enhancing component, or patchy multinodular enhancement. Compared to the images obtained by dynamic MRI, CT-arteriography better demonstrated the nodular enhanced areas, intratumoral feeding arteries and non-enhancing cystic components. The patchy nodular contrast-enhancing pattern was specific for cavernous angioma (Fig. 1). The number of nodules revealed by CT-arteriography correlated with the number of feeding arteries found at surgery. Non-enhancing components were seen in schwannomas (Fig. 2) and carcinomas (Fig. 3), and indicated intratumoral cysts and necrosis, respectively. Many small vessels were visualized by CT-arteriography in meningiomas and benign lacrimal gland
CT arteriography for orbital tumors 549
Table 1 Case No. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.
Age/sex 46/F 54/F 63/M 33/M 52/M 58/F 46/F 46/F 62/F 60/F 64/F 61/F 57/F 41/M
Pathology
CT-arteriography
Dynamic MRI
cavernous angioma cavernous angioma metastasis from lung ca. orbital schwannoma malignant myoepithelioma bil B-cell lymphoma T cell lymphoma bil lacrimal gl lymphoid hyperplasia Wegener’s granulomatosis optic sheath meningioma meningioma meningioma lacrimal gl pleomorphic adenoma lacrimal gl carcinoma
patchy nodular patchy nodular partial partial with cyst partial with cyst homogeneous homogeneous homogeneous homogeneous homogeneous and vessels partial and vessels homogeneous and vessels partial homogeneous and vessels
nodular nodular homogeneous homogeneous with cyst heterogeneous with cyst not available homogeneous homogeneous not available homogeneous not available not available heterogeneous homogeneous
bil = bilateral, gl = gland.
Fig. 1 Cavernous angioma. Dynamic MRI (A, B) and CT-arteriography (C, D) in large (Case 1: A, C) and medium-sized (Case 2: B, D, E) cavernous angioma. A and B: serial axial dynamic MRI (approximately 20-second intervals each) showing patchy central or peripheral enhancement (A: case 1; B: case 2). C: serial axial CT-arteriographic images at the same level obtained 4, 8, and 28 seconds after injection into the internal carotid artery, showing two patchy nodules (Case 1). D: serial axial CT-arteriographic images obtained 4 and 8 seconds after injection into the internal carotid artery, showing two patchy nodules (one located near the retina, the second located mid-tumor), which were comparable to the feeding vessels found at surgery in (Case 2). E: intraoperative photograph. The arrow indicates the second feeding artery, which has been coagulated and divided and was defined in figure 1D.
tumors, which are difficult to differentiate on MRI. Defined vascular structures were found to correlate well with the operative findings (Figs. 4 and 5). The lymphoid lesions showed neither intratumoral feeding arteries nor heterogeneous enhancement (Fig. 6). ª 2005 Elsevier Ltd. All rights reserved.
As well as characteristic findings for various tumors, fine vascular anatomy can be defined using CT-arteriography, including the ophthalmic artery, lacrimal artery, anterior and posterior ethmoidal arteries, central retinal artery, superior ophthalmic vein, Journal of Clinical Neuroscience (2005) 12(5), 548–552
550 Hasegawa et al.
Fig. 2 Orbital schwannoma with multiple cystic components. A: dynamic MRI at the same level (approximately 20-second intervals) shows an irregularly shaped partially enhancing tumor, but the small intratumoral cyst is barely visible. B, C: axial (B: 12, 15 and 18 seconds after contrast material injection) and reconstructed sagittal (C) CT-arteriography showing a large retrobulbar (\) and small intratumoral cyst (arrow). The double arrow indicates the ophthalmic artery.
Fig. 3 Metastatic small cell lung carcinoma (A, B, C: Case 3) and primary orbital adenocarcinoma (D: Case 14). A: dynamic MRI showing a homogeneously enhancing intraorbital tumor with invasion of the lateral orbital wall and temporalis muscle. B, C: CT-arteriography obtained by injection into the external carotid artery (B) and internal carotid artery (C), showing well-demarcated feeding artery territories (*). Arrow: intratumoral necrosis. D: axial CT-arteriography showing external carotid supplied enhancing territory and intratumoral nonenhanced necrotic area (arrow).
and lacrimal vein (Figs. 2, 4, and 6). Extraocular muscles and retina enhance homogeneously. The relationship between the tumor and the vascular and other surrounding anatomical structures of importance was clearly depicted. Additionally, CT-arteriography clearly demonstrated the feeding artery territories from the external carotid or internal carotid arteries in meningiomas and malignant invasive tumors (Fig. 3). Thus detail cannot be obtained using intravenously injected contrast material. DISCUSSION
information obtained from angiography. In addition to bone and soft tissue anatomy, CT-arteriography appropriately reveals normal and pathological intraorbital fine vascular anatomy. An optic nerve engulfed and deviated by the lesion can be welldefined as less enhanced tissue. To maintain visual function during surgical resection of the tumor, not only the optic nerve but also the ophthalmic and central retinal arteries must be preserved. The information provided by CT-arteriography as to the exact location of and the relationship to the tumor mass, fine arteries and veins, external ocular muscles, and the optic nerve, as depicted in this study, is useful to allow safe manipulation of important structures.
Anatomy The orbital cavity contains adipose tissue, muscles, vessels, lacrimal and sebaceous glands, and branches of the cranial nerves. It is not always easy to define the location and relationship of tumor tissue to important surrounding normal structures using Journal of Clinical Neuroscience (2005) 12(5), 548–552
Imaging modalities CT-arteriography, which has been widely recognized as useful to examine the liver and other organs, has been introduced to neuroª 2005 Elsevier Ltd. All rights reserved.
CT arteriography for orbital tumors 551
Fig. 4 Optic sheath meningioma. A: axial dynamic MRI (approximately 20-second intervals) at the same level, showing a large retrobulbar homogeneously enhancing mass. B: DSA of the internal carotid artery shows retrobulbar tumor staining fed by ophthalmic artery (arrow). C: Axial CT-arteriography (3, 4, 5, and 8 seconds after injection), showing the lacrimal artery (arrow), posterolateral ciliary artery (double arrow), ophthalmic artery (crossed arrow), and intratumoral abnormal vessels. Note that the less-enhanced optic nerve (OPTN) embedded in enhancing tumor tissue is clearly visible. The origin of the ophthalmic artery is clearly seen (arrow with *).
Fig. 5 Dynamic images of orbital mixed lacrimal tumor. A: axial dynamic MRI at the same level, showing homogeneously enhancing lacrimal gland tumor (20-second intervals). B: Axial CT-arteriography at the same level (8 seconds after injection), showing heterogeneously enhancing tumor and intratumoral abnormal vessels. Arrow indicates enlarged lacrimal vein.
imaging.6,7,8 Compared with the widely established techniques of dynamic MRI5,9 or two-phase helical CT4 with intravenous contrast medium for orbital tumors, this method is less used. This may be due to the need for troublesome transport of catheterized patients from the DSA to the CT suite. However, since the introduction of DSA and multislice CT systems producing high-quality images using a single patient couch, CT-arteriography may become more popular orbital tumor surgery. Efficacy of CT-arteriography for orbit pathology Accurate preoperative lesion localization and diagnosis should be provided by modern neuroimaging techniques, including CT and MRI. Our correlation of CT-angiography findings and orbital lesion pathology is described above. One of the most specific findª 2005 Elsevier Ltd. All rights reserved.
ings was the patchy nodular contrast enhancement seen in cavernous angioma. Ohtsuka et al. reported the efficacy of dynamic MRI in 2 cases of orbital cavernous angioma, which also had a patchy appearance.5 Small angiomas show homogeneous enhancement.10 In our study, CT-arteriographic images of cavernous angioma were compared in detail with dynamic MRI images. CT-arteriography revealed multiple feeding vessels, barely demonstrable by DSA or conventional MRI. These results correlated with the operative findings of numerous, thin feeding arteries. CT-arteriography appears more accurate in visualizing such pathology. CT arteriography also clearly defined that component of the tumor fed by internal carotid artery from that fed by the external artery in cases of carcinoma and meningioma. This may be useful in estimating the effectiveness of preoperative embolization. Journal of Clinical Neuroscience (2005) 12(5), 548–552
552 Hasegawa et al.
Fig. 6 Lymphoid hyperplasia of the lacrimal gland. A: axial dynamic MRI showing homogeneous enhancement of the lacrimal gland. B and C: early (B) and late (C) phase CT-arteriography with injection of contrast into the internal carotid artery, showing normal vascular structure including ophthalmic (arrow) and central retinal (side by side arrows) arteries, and homogenous gland enhancement with small abnormal intratumoral vessels. D: CT-arteriography with injection of contrast into the external carotid artery, showing normal vascular structures, including the superior ophthalmic (arrow), lacrimal (side by side arrows) and medial temporal (double) veins, and homogeneous enhancement of the gland.
REFERENCES 1. Demirci H, Shields CL, Shields JA, Honavar SG, Mercado GJ, Tovilla JC. Orbital tumors in the older adult population. Ophthalmology 2002; 109: 243–248. 2. Maroon JC, Kennerdell JS, Abla A. The diagnosis and treatment of orbital tumors. Clin Neurosurg 1988; 34: 485–498. 3. Kang JK, Lee IW, Jeun SS et al. Tumors of the orbit. Pitfalls of the surgical approach in 37 children with orbital tumor. Childs Nerv Syst 1997; 13: 536–541. 4. Moon WJ, Na DG, Ryoo JW et al. Orbital lymphoma and subacute or chronic inflammatory pseudotumor: differentiation with two-phase helical computed tomography. J Comput Assist Tomogr 2003; 27: 510–516. 5. Ohtsuka K, Hashimoto M, Akiba H. Serial dynamic magnetic resonance imaging of orbital cavernous hemangioma. Am J Ophthalmol 1997; 123: 396–398.
Journal of Clinical Neuroscience (2005) 12(5), 548–552
6. Hasegawa M, Fujisawa H, Kawamura T, Yamashita J, Matsui O. The efficacy of CT arteriography for spinal arteriovenous fistula surgery: technical note. Neuroradiology 1999; 41: 915–919. 7. Nomura M, Kida S, Uchiyama N et al. CT during selective arteriography: anatomical assessment of unruptured intracranial aneurysms before endovascular treatment. Neuroradiology 2001; 43: 735–741. 8. Tomura N, Hashimoto M, Sashi R et al. Superselective angio-CT of brain tumors. AJNR Am J Neuroradiol 1996; 17: 1073–1080. 9. Shinaver CN, Mafee MF, Choi KH. MRI of mesenchymal chondrosarcoma of the orbit: case report and review of the literature. Neuroradiology 1997; 39: 296–301. 10. Thorn-Kany M, Arrue P, Delisle MB, Lacroix F, Lagarrigue J, Manelfe C. Cavernous hemangiomas of the orbit: MR imaging. J Neuroradiol 1999; 26: 79–86.
ª 2005 Elsevier Ltd. All rights reserved.