- Email: [email protected]
Mistaken identity: a case of false positive on CT angiography
464 Kazemi et al. REFERENCES 1. 2.
3.
4. 5. 6. 7. 8.
9.
10.
11.
Kobayashi S, Okada K, Onoda K, Horikoshi S. Ossification of the cervical ligamentum flavum. Surg Neurol 1991; 35: 234±238. Kubota M, Baba I, Sumida I. Myelopathy due to ossification of the ligamentum flavum of the cervical spine. A report of two cases. Spine 1981; 6: 553±559. Nakajima K, Miyaoka M, Sumie H, Nakazato T, Ishii S. Cervical radiculomyelopathy due to calcification of the ligamentum flavum. Surg Neurol 1984; 21: 479±488. Taneichi H, Kaneda K. Symptomatology of ossification of the ligamentum flavum. Spine and Spinal Cord 1998; 11: 485±489 (Jpn). Saito M. Diagnostic imaging of ossification of the ligamentum flavum. Spine and Spinal Cord 1998; 11: 499±503 (Jpn). Stoltmann HF. The role of the ligamenta flava in the pathogenesis of myelopathy in cervical spondylosis. Brain 1964; 86: 45±54. Otani K, Aihara T, Tanaka A, Shibasaki K. Ossification of the ligamentum flavum of the thoracic spine. Int Orthop 1986; 10: 135±139. Saiki K, Hattori S, Kawai S, Miyamoto T, Tsue K, Kotani H. The ossification of the yellow ligament in the thoracic spine ± Incidence, classification, neurological findings and narrow spinal canal. Seikei Geka 1981; 24: 191±198 (Jpn). Sato T, Kokubu S, Ishii Y. Choice of operative method for ossification of ligamentum flavum based on CT findings. Rinshoseikeigeka 1996; 31: 541±545 (Jpn). Yanagi T, Naito A, Yasuda T, Hashizume Y, Oomori K. The ossification of the ligamentum flavum of the thoracic spine; correlative CT and pathologic study. Seikeigeka 1987; 38: 297±307 (Jpn). Miyasaka K, Kaneda K, Sato S. Myelopathy due to ossification or calcification of the ligamentum flavum: radiologic and histologic evaluations. AJNR 1983; 4: 629±632.
Mistaken identity: a case of false positive on CT angiography N. J. Kazemi1 MBBS, B. Dennien2 FRACR, N. G. Dan1 FRCS FRACS 1 Department of Neurosurgery, 2Department of Radiology, Concord Repatriation General Hospital, University of Sydney, Sydney, Australia
Summary We describe the case of a 42-year-old female presenting with subarachnoid haemorrhage from a posterior inferior cerebellar artery (PICA) aneurysm rupture on intracranial digital subtraction angiography (DSA). One year postoperatively, the patient was followed with CT angiography and was reported to show a de novo aneurysm at the bifurcation of the left internal carotid artery (ICA). Subsequent DSA revealed an aberrant vein crossing over the ICA bifurcation on mask phase images. This is the first reported case of a such a reason for a `false positive' on CT angiography (CTA). The case demonstrates that although CTA has a reported high specificity, careful interpretation of multiple views is required to diagnose intracranial aneurysms when compared to the `gold' standard of CTA. & 2002 Published by Elsevier Science Ltd. Journal of Clinical Neuroscience (2002) 9(4), 464±466 & 2002 Published by Elsevier Science Ltd. DOI: 10.1054/jocn.2001.0984, available online at http://www.idealibrary.com on
Keywords: aneurysm, intracranial, computed tomographic angiography, digital subtraction angiography, subarachnoid haemorrhage Received 11 July 2001 Accepted 31 July 2001 Correspondence to: Dr N. J. Kazemi, 118A Warriewood Road, Warriewood NSW 2102, Australia
Journal of Clinical Neuroscience (2002) 9(4)
Three-dimensional CT angiography (CTA) is increasingly recognised as a useful way of evaluating patients with suspected acute subarachnoid haemorrhage or intracranial aneurysm. In comparison to the gold standard of intracranial digital subtraction angiography (DSA), intracranial CTA is a fast and minimally invasive method with a high diagnostic accuracy, sensitivity and specificity. However, limitations still exist despite continually improving CTA interpretation. Here we illustrate a reason for a false positive result on CTA. A 42-year-old female presented with subarachnoid haemorrhage evident on non-contrast CT scan in February 2000. The scan also revealed intraventricular haemorrhage and hydrocephalus at this time. Subsequent digital subtraction angiography revealed an aneurysm arising from the origin of the left posterior inferior cerebellar artery (PICA) with a branch vessel arising posteriorly from the fundus of the aneurysm. The patient was treated with an external ventricular drain for hydrocephalus and subsequently underwent a craniotomy for intended clipping of the left PICA aneurysm. However, at operation, the fusiform nature of the aneurysm and consideration of the branch vessel resulted in `wrapping' of the aneurysm. The patient's subsequent recovery was delayed by infection, but subsequent progress was otherwise uneventful and the patient was discharged 25 days after admission. Follow-up monitoring with a CT angiogram at 6 months showed a decrease in the size of the PICA aneurysm and no other abnormalities. Subsequent CT angiogram at an outside institution 1 year after initial presentation, however, strongly suggested a de novo aneurysm at the bifurcation of the left internal carotid artery (ICA) (Figs 1±3). The patient was investigated with a digital subtraction angiogram for pre-operative planning (Figs 4±6). In Figures 5 and 6, the arterial and venous selection phases are superimposed and clearly demonstrate no left ICA aneurysm but illustrate an aberrant vein crossing over the left ICA bifurcation. This DSA explains the CTA finding of the aneurysm and is an example of a false positive on CT angiography. DISCUSSION CT angiography is establishing an important place in the detection and pre-operative evaluation of patients with suspected intracranial aneurysms. There are many studies which now demonstrate high sensitivity and specificity rates in the detection of intracranial aneurysms. In the study by Zouaoui,1 CTA demonstrated sensitivity and specificity rates of up to 97% and 100% respectively. CTA is recognised as simple, fast and non-invasive in comparison to DSA, and is useful for screening in relatives of those with intracranial aneurysms.2 The main difficulties in CTA lie with the detection of small aneurysms (<4 mm),3 aneurysms of the proximal ICA and ophthalmic artery close to bone, such as the skull base4,5 and loss of information due to artefact from surgical clips.6,7 This case presents an unusual and previously unreported reason for the detection of a false positive aneurysm on CTA. After aneurysm wrapping, our patient was followed with CT angiography to assess the size of the original PICA aneurysm that had been wrapped, as well as any de novo aneurysm formation. The second aneurysm, reported 1 year postoperatively on CTA at the bifurcation of the left ICA, was seen on axial, coronal and sagittal reformats. & 2002 Published by Elsevier Science Ltd.
A case of false positive on CT angiography 465
Figs 1±3 CT angiogram ± coronal, axial and sagittal reformats. These reveal a small rounded enhancing structure projecting superiorly from the left ICA bifurcation. This had been reported as a left ICA bifurcation aneurysm. Figure 3 reveals a curvilinear structure wrapping around the distal left ICA bifurcation. The arrow points to the reported left ICA bifurcation de novo aneurysm.
& 2002 Published by Elsevier Science Ltd.
Figs 4±6 (4) Digital subtraction angiography ± arterial phase. Left ICA injection anteroposterior view reveals normal anatomy, excluding the presence of a de novo aneurysm as reported on CTA. (5) DSA ± left ICA injection, A-P view. A mask image has been chosen during the venous phase of the injection, resulting in white venous structures superimposed on the black arterial image. The arrow points to the aberrant vein crossing the left ICA bifurcation. (6) DSA ± left ICA injection, lateral view. This venous phase mask image shows the vein identified running under the temporal lobe in the floor of the middle cranial fossa. The vein is seen connecting the sphenoparietal sinus with the transverse sinus.
Journal of Clinical Neuroscience (2002) 9(4)
466 Lath et al.
The subsequent DSA images revealed a prominent vein superimposed on the left ICA bifurcation creating the impression, on CTA, of a significant second de novo aneurysm. This was the reason for the CTA finding. Although this is the first reported case of a `false positive' due to superimposition of venous and arterial structures, another study has pointed to the difficulty of separating the two from their simultaneous enhancement on CTA.8 In that study, the incidental finding of sagittal sinus thrombosis was detected in the periphery of the CTA source images. Although the specificity of CTA is considered very high, with many studies quoting rates as high as 100%, there are nonetheless important causes of `false-positive' results. We demonstrate that the superimposition of venous on arterial vasculature may also be a source of error in the detection of intracranial aneurysms on CTA. This example is the first reported case of such a problem posed in the circle of Willis as demonstrated on CTA. REFERENCES 1.
2.
3.
4.
5.
6.
7.
8.
Zouaoui A, Sahel M, Marro B et al. Three-dimensional computed tomographic angiography in detection of cerebral aneurysms in acute subarachnoid haemorrhage. Technical Report. Neurosurgery 1997; 41: 125±130. Young N, Dorsch NWC, Kingston RJ. Pitfalls in the use of spiral CT for identification of intracranial aneurysms. Neuroradiology 1999; 41: 93±99. Anderson GB, Steinke DE, Petruk KC, Ashforth R, Findlay JM. Computed tomographic angiography versus digital subtraction angiography for the diagnosis and early treatment of ruptured intracranial aneurysms. Neurosurgery 1999; 45: 1315±1322. Liang EY, Chan M, Hsiang JHK et al. Detection and assessment of intracranial aneurysms. Value of CT angiography with shaded-surface display. AJR 1995; 165: 1497±1502. Strayle-Batra M, Skalej M, Wakhloo AK, Ernemann U, Klier R, Voigt K. Three-dimensional spiral CT angiography in the detection of cerebral aneurysm. Acta Radiologica 1998; 39: 233±238. Schwartz RB, Tice HM, Hooten SM, Hsu L, Stieg PE. Evaluation of cerebral aneurysms with helical CT. Correlation with conventional angiography and MR angiography. Radiology 1994; 92: 717±722. Tampieri D, Leblanc R, Oleszek J, Pokrupa R, Melancon D. Three-dimensional computed tomographic angiography of cerebral aneurysms. Neurosurgery 1995; 36: 749±755. Alberico RA, Patel M, Casey S, Jacobs B, Maguire W, Decker R. Evaluation of the circle of Willis with three-dimensional CT angiography in patients with suspected intracranial aneurysms. Am J Neuroradiol 1995; 16: 1571±1578.
Traumatic aneurysm of the callosomarginal artery Rahul Lath1 MBBS MCH (Neurosurgery), Atluri Vaniprasad1 2 1 MBBS, Evelyn Kat MBBS, Brian P. Brophy FRACS Departments of 1Neurosurgery and 2Radiology, Flinders Medical Centre, Bedford Park, SA 5042, Australia
Summary Intracranial aneurysms are rare complications of head injury. The primary goals in the management of patients harbouring these lesions are early identification and intervention to prevent bleeding or rebleeding. The authors present a case of traumatic false aneurysm of the callosomarginal artery which was diagnosed following head injury and managed successfully with a good outcome. & 2002 Published by Elsevier Science Ltd. Journal of Clinical Neuroscience (2002) 9(4)
Journal of Clinical Neuroscience (2002) 9(4), 466±468 & 2002 Published by Elsevier Science Ltd. DOI: 10.1054/jocn.2001.1050, available online at http://www.idealibrary.com on
Keywords: traumatic aneurysm, callosomarginal artery, false aneurysm Received 11 July 2001 Accepted 31 July 2001 Correspondence to: Dr. Brian P. Brophy, Department of Neurosurgery, Flinders Medical Centre, Bedford Park, SA 5042, Australia. Tel.: 61 8 8204 4671; Fax: 61 8 8204 5116; E-mail: [email protected]
INTRODUCTION Post-traumatic intracranial aneurysms are rare and constitute less than 1% of all aneurysms in large series.1±3 Post-traumatic intracranial aneurysms have been reported in almost all major intracranial arteries but are more common in the middle cerebral and pericallosal arteries.1,2,4±10 In the literature there are very few reports of a traumatic aneurysm of the callosomarginal artery.2,11±13 The most frequent causes of peripheral traumatic aneurysms are closed head trauma (62%), penetrating wounds (27%), and iatrogenic trauma (11%).5 Rupture of traumatic aneurysms usually presents with subarachnoid, intraparenchymal, subdural or intraventricular haemorrhage.4,7 Since computed tomography has replaced cerebral angiography as the neuroradiological procedure of choice in the setting of acute head injury, the early diagnosis of this entity may have become less common. In this case report we discuss the early diagnosis and management of a young woman with a post-traumatic false aneurysm of the callosomarginal artery.
CASE REPORT A 23 year old woman, a front seat passenger in a car, sustained a severe head injury when the car in which she was travelling hit a tree at high speed. She was hospitalised in a comatose state with an initial Glasgow Coma Score of 3/15, which later improved to 8/15. CT scan of the head showed right frontal intracerebral juxta falcine haematoma and blood in the interhemispheric fissure (Fig. 1). The unusual location of the haematoma and presence of interhemispheric blood prompted cerebral angiography, which showed an aneurysm in the left callosomarginal artery at the bifurcation of the distal anterior cerebral artery into the pericallosal and callosomarginal arteries (Fig. 2). She underwent right frontal craniotomy and the haematoma was evacuated. A complete tear was noted in the left callosomarginal artery, which required a clip to be placed along the tear and the vessel had to be sacrificed. Macroscopically the resected tissue was made up of blood clot and clinically was consistent with a false aneurysm. Histopathology revealed an organised haematoma with fibrin and admixed white cell elements. No vessel wall elements could be identified and the appearances of the lesion were consistent with a diagnosis of a false aneurysm. The patient made an uneventful postoperative recovery and was discharged in good general and neurological condition. At follow up 6 months later there were no neurological deficits. & 2002 Published by Elsevier Science Ltd.
3.
4. 5. 6. 7. 8.
9.
10.
11.
Kobayashi S, Okada K, Onoda K, Horikoshi S. Ossification of the cervical ligamentum flavum. Surg Neurol 1991; 35: 234±238. Kubota M, Baba I, Sumida I. Myelopathy due to ossification of the ligamentum flavum of the cervical spine. A report of two cases. Spine 1981; 6: 553±559. Nakajima K, Miyaoka M, Sumie H, Nakazato T, Ishii S. Cervical radiculomyelopathy due to calcification of the ligamentum flavum. Surg Neurol 1984; 21: 479±488. Taneichi H, Kaneda K. Symptomatology of ossification of the ligamentum flavum. Spine and Spinal Cord 1998; 11: 485±489 (Jpn). Saito M. Diagnostic imaging of ossification of the ligamentum flavum. Spine and Spinal Cord 1998; 11: 499±503 (Jpn). Stoltmann HF. The role of the ligamenta flava in the pathogenesis of myelopathy in cervical spondylosis. Brain 1964; 86: 45±54. Otani K, Aihara T, Tanaka A, Shibasaki K. Ossification of the ligamentum flavum of the thoracic spine. Int Orthop 1986; 10: 135±139. Saiki K, Hattori S, Kawai S, Miyamoto T, Tsue K, Kotani H. The ossification of the yellow ligament in the thoracic spine ± Incidence, classification, neurological findings and narrow spinal canal. Seikei Geka 1981; 24: 191±198 (Jpn). Sato T, Kokubu S, Ishii Y. Choice of operative method for ossification of ligamentum flavum based on CT findings. Rinshoseikeigeka 1996; 31: 541±545 (Jpn). Yanagi T, Naito A, Yasuda T, Hashizume Y, Oomori K. The ossification of the ligamentum flavum of the thoracic spine; correlative CT and pathologic study. Seikeigeka 1987; 38: 297±307 (Jpn). Miyasaka K, Kaneda K, Sato S. Myelopathy due to ossification or calcification of the ligamentum flavum: radiologic and histologic evaluations. AJNR 1983; 4: 629±632.
Mistaken identity: a case of false positive on CT angiography N. J. Kazemi1 MBBS, B. Dennien2 FRACR, N. G. Dan1 FRCS FRACS 1 Department of Neurosurgery, 2Department of Radiology, Concord Repatriation General Hospital, University of Sydney, Sydney, Australia
Summary We describe the case of a 42-year-old female presenting with subarachnoid haemorrhage from a posterior inferior cerebellar artery (PICA) aneurysm rupture on intracranial digital subtraction angiography (DSA). One year postoperatively, the patient was followed with CT angiography and was reported to show a de novo aneurysm at the bifurcation of the left internal carotid artery (ICA). Subsequent DSA revealed an aberrant vein crossing over the ICA bifurcation on mask phase images. This is the first reported case of a such a reason for a `false positive' on CT angiography (CTA). The case demonstrates that although CTA has a reported high specificity, careful interpretation of multiple views is required to diagnose intracranial aneurysms when compared to the `gold' standard of CTA. & 2002 Published by Elsevier Science Ltd. Journal of Clinical Neuroscience (2002) 9(4), 464±466 & 2002 Published by Elsevier Science Ltd. DOI: 10.1054/jocn.2001.0984, available online at http://www.idealibrary.com on
Keywords: aneurysm, intracranial, computed tomographic angiography, digital subtraction angiography, subarachnoid haemorrhage Received 11 July 2001 Accepted 31 July 2001 Correspondence to: Dr N. J. Kazemi, 118A Warriewood Road, Warriewood NSW 2102, Australia
Journal of Clinical Neuroscience (2002) 9(4)
Three-dimensional CT angiography (CTA) is increasingly recognised as a useful way of evaluating patients with suspected acute subarachnoid haemorrhage or intracranial aneurysm. In comparison to the gold standard of intracranial digital subtraction angiography (DSA), intracranial CTA is a fast and minimally invasive method with a high diagnostic accuracy, sensitivity and specificity. However, limitations still exist despite continually improving CTA interpretation. Here we illustrate a reason for a false positive result on CTA. A 42-year-old female presented with subarachnoid haemorrhage evident on non-contrast CT scan in February 2000. The scan also revealed intraventricular haemorrhage and hydrocephalus at this time. Subsequent digital subtraction angiography revealed an aneurysm arising from the origin of the left posterior inferior cerebellar artery (PICA) with a branch vessel arising posteriorly from the fundus of the aneurysm. The patient was treated with an external ventricular drain for hydrocephalus and subsequently underwent a craniotomy for intended clipping of the left PICA aneurysm. However, at operation, the fusiform nature of the aneurysm and consideration of the branch vessel resulted in `wrapping' of the aneurysm. The patient's subsequent recovery was delayed by infection, but subsequent progress was otherwise uneventful and the patient was discharged 25 days after admission. Follow-up monitoring with a CT angiogram at 6 months showed a decrease in the size of the PICA aneurysm and no other abnormalities. Subsequent CT angiogram at an outside institution 1 year after initial presentation, however, strongly suggested a de novo aneurysm at the bifurcation of the left internal carotid artery (ICA) (Figs 1±3). The patient was investigated with a digital subtraction angiogram for pre-operative planning (Figs 4±6). In Figures 5 and 6, the arterial and venous selection phases are superimposed and clearly demonstrate no left ICA aneurysm but illustrate an aberrant vein crossing over the left ICA bifurcation. This DSA explains the CTA finding of the aneurysm and is an example of a false positive on CT angiography. DISCUSSION CT angiography is establishing an important place in the detection and pre-operative evaluation of patients with suspected intracranial aneurysms. There are many studies which now demonstrate high sensitivity and specificity rates in the detection of intracranial aneurysms. In the study by Zouaoui,1 CTA demonstrated sensitivity and specificity rates of up to 97% and 100% respectively. CTA is recognised as simple, fast and non-invasive in comparison to DSA, and is useful for screening in relatives of those with intracranial aneurysms.2 The main difficulties in CTA lie with the detection of small aneurysms (<4 mm),3 aneurysms of the proximal ICA and ophthalmic artery close to bone, such as the skull base4,5 and loss of information due to artefact from surgical clips.6,7 This case presents an unusual and previously unreported reason for the detection of a false positive aneurysm on CTA. After aneurysm wrapping, our patient was followed with CT angiography to assess the size of the original PICA aneurysm that had been wrapped, as well as any de novo aneurysm formation. The second aneurysm, reported 1 year postoperatively on CTA at the bifurcation of the left ICA, was seen on axial, coronal and sagittal reformats. & 2002 Published by Elsevier Science Ltd.
A case of false positive on CT angiography 465
Figs 1±3 CT angiogram ± coronal, axial and sagittal reformats. These reveal a small rounded enhancing structure projecting superiorly from the left ICA bifurcation. This had been reported as a left ICA bifurcation aneurysm. Figure 3 reveals a curvilinear structure wrapping around the distal left ICA bifurcation. The arrow points to the reported left ICA bifurcation de novo aneurysm.
& 2002 Published by Elsevier Science Ltd.
Figs 4±6 (4) Digital subtraction angiography ± arterial phase. Left ICA injection anteroposterior view reveals normal anatomy, excluding the presence of a de novo aneurysm as reported on CTA. (5) DSA ± left ICA injection, A-P view. A mask image has been chosen during the venous phase of the injection, resulting in white venous structures superimposed on the black arterial image. The arrow points to the aberrant vein crossing the left ICA bifurcation. (6) DSA ± left ICA injection, lateral view. This venous phase mask image shows the vein identified running under the temporal lobe in the floor of the middle cranial fossa. The vein is seen connecting the sphenoparietal sinus with the transverse sinus.
Journal of Clinical Neuroscience (2002) 9(4)
466 Lath et al.
The subsequent DSA images revealed a prominent vein superimposed on the left ICA bifurcation creating the impression, on CTA, of a significant second de novo aneurysm. This was the reason for the CTA finding. Although this is the first reported case of a `false positive' due to superimposition of venous and arterial structures, another study has pointed to the difficulty of separating the two from their simultaneous enhancement on CTA.8 In that study, the incidental finding of sagittal sinus thrombosis was detected in the periphery of the CTA source images. Although the specificity of CTA is considered very high, with many studies quoting rates as high as 100%, there are nonetheless important causes of `false-positive' results. We demonstrate that the superimposition of venous on arterial vasculature may also be a source of error in the detection of intracranial aneurysms on CTA. This example is the first reported case of such a problem posed in the circle of Willis as demonstrated on CTA. REFERENCES 1.
2.
3.
4.
5.
6.
7.
8.
Zouaoui A, Sahel M, Marro B et al. Three-dimensional computed tomographic angiography in detection of cerebral aneurysms in acute subarachnoid haemorrhage. Technical Report. Neurosurgery 1997; 41: 125±130. Young N, Dorsch NWC, Kingston RJ. Pitfalls in the use of spiral CT for identification of intracranial aneurysms. Neuroradiology 1999; 41: 93±99. Anderson GB, Steinke DE, Petruk KC, Ashforth R, Findlay JM. Computed tomographic angiography versus digital subtraction angiography for the diagnosis and early treatment of ruptured intracranial aneurysms. Neurosurgery 1999; 45: 1315±1322. Liang EY, Chan M, Hsiang JHK et al. Detection and assessment of intracranial aneurysms. Value of CT angiography with shaded-surface display. AJR 1995; 165: 1497±1502. Strayle-Batra M, Skalej M, Wakhloo AK, Ernemann U, Klier R, Voigt K. Three-dimensional spiral CT angiography in the detection of cerebral aneurysm. Acta Radiologica 1998; 39: 233±238. Schwartz RB, Tice HM, Hooten SM, Hsu L, Stieg PE. Evaluation of cerebral aneurysms with helical CT. Correlation with conventional angiography and MR angiography. Radiology 1994; 92: 717±722. Tampieri D, Leblanc R, Oleszek J, Pokrupa R, Melancon D. Three-dimensional computed tomographic angiography of cerebral aneurysms. Neurosurgery 1995; 36: 749±755. Alberico RA, Patel M, Casey S, Jacobs B, Maguire W, Decker R. Evaluation of the circle of Willis with three-dimensional CT angiography in patients with suspected intracranial aneurysms. Am J Neuroradiol 1995; 16: 1571±1578.
Traumatic aneurysm of the callosomarginal artery Rahul Lath1 MBBS MCH (Neurosurgery), Atluri Vaniprasad1 2 1 MBBS, Evelyn Kat MBBS, Brian P. Brophy FRACS Departments of 1Neurosurgery and 2Radiology, Flinders Medical Centre, Bedford Park, SA 5042, Australia
Summary Intracranial aneurysms are rare complications of head injury. The primary goals in the management of patients harbouring these lesions are early identification and intervention to prevent bleeding or rebleeding. The authors present a case of traumatic false aneurysm of the callosomarginal artery which was diagnosed following head injury and managed successfully with a good outcome. & 2002 Published by Elsevier Science Ltd. Journal of Clinical Neuroscience (2002) 9(4)
Journal of Clinical Neuroscience (2002) 9(4), 466±468 & 2002 Published by Elsevier Science Ltd. DOI: 10.1054/jocn.2001.1050, available online at http://www.idealibrary.com on
Keywords: traumatic aneurysm, callosomarginal artery, false aneurysm Received 11 July 2001 Accepted 31 July 2001 Correspondence to: Dr. Brian P. Brophy, Department of Neurosurgery, Flinders Medical Centre, Bedford Park, SA 5042, Australia. Tel.: 61 8 8204 4671; Fax: 61 8 8204 5116; E-mail: [email protected]
INTRODUCTION Post-traumatic intracranial aneurysms are rare and constitute less than 1% of all aneurysms in large series.1±3 Post-traumatic intracranial aneurysms have been reported in almost all major intracranial arteries but are more common in the middle cerebral and pericallosal arteries.1,2,4±10 In the literature there are very few reports of a traumatic aneurysm of the callosomarginal artery.2,11±13 The most frequent causes of peripheral traumatic aneurysms are closed head trauma (62%), penetrating wounds (27%), and iatrogenic trauma (11%).5 Rupture of traumatic aneurysms usually presents with subarachnoid, intraparenchymal, subdural or intraventricular haemorrhage.4,7 Since computed tomography has replaced cerebral angiography as the neuroradiological procedure of choice in the setting of acute head injury, the early diagnosis of this entity may have become less common. In this case report we discuss the early diagnosis and management of a young woman with a post-traumatic false aneurysm of the callosomarginal artery.
CASE REPORT A 23 year old woman, a front seat passenger in a car, sustained a severe head injury when the car in which she was travelling hit a tree at high speed. She was hospitalised in a comatose state with an initial Glasgow Coma Score of 3/15, which later improved to 8/15. CT scan of the head showed right frontal intracerebral juxta falcine haematoma and blood in the interhemispheric fissure (Fig. 1). The unusual location of the haematoma and presence of interhemispheric blood prompted cerebral angiography, which showed an aneurysm in the left callosomarginal artery at the bifurcation of the distal anterior cerebral artery into the pericallosal and callosomarginal arteries (Fig. 2). She underwent right frontal craniotomy and the haematoma was evacuated. A complete tear was noted in the left callosomarginal artery, which required a clip to be placed along the tear and the vessel had to be sacrificed. Macroscopically the resected tissue was made up of blood clot and clinically was consistent with a false aneurysm. Histopathology revealed an organised haematoma with fibrin and admixed white cell elements. No vessel wall elements could be identified and the appearances of the lesion were consistent with a diagnosis of a false aneurysm. The patient made an uneventful postoperative recovery and was discharged in good general and neurological condition. At follow up 6 months later there were no neurological deficits. & 2002 Published by Elsevier Science Ltd.