- Email: [email protected]
Confirmation of traumatic interhemispheric subdural hematoma by magnetic resonance imaging
TheJournalof Emergency Medicine,Vol 12,No 3, pp 369-373, 1994 Copyright0 1994ElsevierscienceLtd Printedin theUSA.All rightsreserved
Pergamon
0736~4679/94$6.00 + 30
-----
s4Bkctd TbpkS
Emtwgency
Radiology
CONFMWHATION OF TRAUMATIC INTERtlEMIBPHERIC SUBDURAL W fMATOMA BY MAGNETIC RESONANCE tAllAGING Valerie A. Romano, DO, and Gilbert J. Toffol, DO Depaltment of Internal Medicine, Division of Neurology, Mesa General Hospital Medical Center, Mesa, Arizona Reprint Address: Gilbert J. Toffol, DO, 4244 North 19th Avenue, Phoenix, AZ 85015
[I Abstract- We report a case of interhemispheric subdural hematoma following closed head injury producing contralateral neurological findings and focal seizures. Noncontrast cranial computed tomography scan was initiaily reported to be normai, but magnetic resonance imaging of the brain demonstrated an interhemispheric subdural hemstoma. Head injury, specifically occipital, is the leading cause of interhemispheric subdural hematoma in adults. Most patients develop a “falx syndrome.” If adequately interpreted, magnetic resonance imaging of the brain showing the appearance of blood on Tl- and T2weighted images can detect interhemispheric subdural hematoma. However, computed tomography scan should always be done first to detect intercranial bleeding, and it should be performed with and without contrast in patients with prior head trauma and delayed bleeds.
mental status changes,and contralateral isolated paresis of one leg or hemiparesis,worse in the leg than the arm, the so called “falx syndrome”(4). We report a caseof an elderly lady who presentedto Mesa General Hospital’s Emergency Department with a falx syndrome and focal motor seizures due to head trauma secondaryto an ISH. Magnetic resonanceimaging (MRI scan) confirmed the diagnosis after the initial CT scanwas reported to be unremarkable.We discuss the abnormalities of Tl- and TZ-weighted MR imagesthat help confirm the presenceof blood, since MRI is not often used for acute trauma or bleeds in the emergency department. This lesion needsto be sought in adults as well as children.
7 Keywords - hematoma; falx syndrome; trauma; imaging; craniotomy
CASE REPORT
Two weeksprior to admission,an 80-year-oldwoman with hypertension sustained a head injury. The patient slipped and hit the occipital region of her head against the wall with force great enough to create a hole in the plaster. There was no loss of consciousness,and the patient experiencedno immediate effects. On the day of admission, the patient, on examination, had left-sided weaknesspredominantly affecting the leg and sparing the face (falx syndrome) and focal motor seizureactivity of the left leg with a
INTRODUCTION
Traumatic interhemisphericsubduralhematoma(ISH) is commonly seenin abusedchildren who have suffered severehead shaking (1,2) and rarely occurs in adults (3). An ISH is usually diagnosedby history and physical examination and confirmed by computed tomography (CT scan). Clinical findings suggestiveof ISH include paraparesis,seizures,delayed
Radiology-This sectionof JEM containsarticlesof interestandoriginalresearch related to emergency radiology and is coordinated by Jock Keene, MD, of St. Francis Hospital, Poughkeepsie, New York. RECEIVED: 30 December1992;FINAL SUBMISSIONRECEIVED: 28 September1993; ACCEPTED:
8 October 1993
369
370
Valerie A. Roman0 and Gilbert J. Toffol
Jacksonian march to the left arm. This was treated initially with IV diazepam and later with phenytoin. A noncontrast CT scan of the head (Figure 1) was initially reported to be unremarkable. An electroencephalogram (EEG) showed cortical irritability compatible with seizure tendency in the right hemisphere. An MRI was obtained 2 days later to rule out a structural lesion, and it showed a subacute falx subdural hematoma or ISH (Figures 2 and 3). The patient was discharged on phenytoin, and physical therapy provided gait training and ambulation. DISCUSSION An ISH is a rare finding that generally occurs following trauma. A history of loss of consciousnessor evidence of skull fracture is not usually associated with an ISH (5). Several studies have shown the site of trauma to be the occipital region (5-7). A sharp blow to the occiput causes posterior movement of the cerebral hemisphererelative to the fixed superior sagittal sinus. This maximally stretches the veins, leading to an increased risk of tearing. The mechanism of production of the hematoma is likely to be a rotational injury with shearing of the bridging veins between the medial border of the cerebral hemisphere and the sinus. The hematoma remains in the interhemispheric region due to the adherenceof the arachnoid trabeculations between the brain and the parasagittal dura.
Figure 1. Noncontrast CT scan showlng an ill-defined linear hypodenslty along the right parasaglttal cerebral hemlsphere. In retrospect, there is lnterhemispherlc hyperdenslty.
Figure 2A. Coronal Tl-weighted MRI Image showing an abnormal hyperlntense signal along the right side of the falx cerebri.
Hemiparesis, worse in the lower than the upper extremity (falx syndrome), or lower extremity monoparesis is characteristic of the ISH lesion (6). Other symptoms of an ISH include vomiting, lethargy, headache, seizures, and mental status changes (3,5,6). An ISH often has a subacute or chronic course with the onset of focal neurologic signs appearing more than 48 hours after the injury (8). The falx syndrome is also produced by other causes.The differential diagnosis includes occlusion of an anterior cerebral artery, interhemispheric empyema, and anterior communicating artery aneurysm with subarachnoid hemorrhage (3,6). Both interhemispheric empyema and subdural hematoma produce the falx syndrome due to a mass effect (7). Diagnosis of an ISH should be considered whenever a CT scan shows the image of a hematoma near the m idline with a flat broad base attached to the falx with a convex lateral border (9). The hematoma also frequently extends along the leaflet of the tentorium cerebelli (10). The CT scan is an excellent modality for diagnosis of an ISH; however, the CT scan occasionally will not reveal a subacute or chronic hematoma, unless the study is made with and without contrast (11). Another causefor a false negative non-
Interhemispheric Subdural Hematoma on MRI
Flgure 28. Sagittal Tl-weighted toma.
371
MRI image showing the abnormal hyperintense slgnal compatible with a falx subdural hema-
Figure 3A. Axlal Tl-weighted MRI image showing a hyperintense slgnal atong the right side of the falx cerebri.
Figure 38. Axial T2-wetghM #&RI image also showing a hyperlntense tdgnel compatible with the dkgneals of a subacute bleed.
372
Valerie A. Roman0 and Gilbert J. Toffol
contrast CT scan in the presence of subacute or chronic subdural hematomas is a hematocrit less than 20%. Contralateral paresis of the lower extremity out of proportion to the arm and face may provide a clue to the location of the lesion. Therefore, an unremarkable CT scan, along with the clinical manifestation of a falx syndrome, should warrant an MRI scan. In retrospect, our patient’s noncontrast CT scan was abnormal and should have been interpreted as suggesting the possibility of an interhemispheric collection of isodenseblood. Any imaging modality used for diagnosing central nervous system (CNS) disorders should detect or exclude hemorrhage with a high degree of accuracy if properly interpreted. The MRI scan is a very sensitive and specific technique for diagnosing intracranial bleed, except for subarachnoid hemorrhage (12). Acute, subacute, and chronic stages of blood can be identified by characteristic appearances of deoxyhemoglobin, methemoglobin, and hemosiderin, respectively, on an MRI scan (11). Changes in signal intensity associated with hemorrhage are generally opposite those accompanying most CNS pathologies. For reference in viewing MRI studies, normal cerebrospinal fluid (CSF) appears dark or black (low signal intensity) on Tl-weighted images and bright or white (high signal intensity) on T2-weighted images. The so-called intermediate weighted or proton density study has the CSF appearing gray, similar to the brain parenchyma signal. Tissues with short Tl relaxation times appear bright on Tl-weighted images and include fat, subacute hemorrhage (methemoglobin), and enhancing tissue (gadolinium) (12). Tissues with short T2 relaxation times appear dark, and these include acute hematoma (less than 7 days old), hemosiderin-laden macrophages, and ferritin (12). Therefore, areas of high signal intensity on Tlweighted images and low signal intensity on T2-
weighted images may indicate acute hemorrhage (11). Subacute (between 1 week and a month old) intraparenchymal or subdural hematomas have high signal intensities seen on both Tl- and T2-weighted images (13). Chronic hematomas (more than a month old) may have several appearances on TZweighted images, but usually TZweighted images show a high intensity lesion surrounded by a thin rim of low signal intensity representing hemosiderin deposition around the bleed (13). Once a lesion has been characterized as a hematoma, location, patient age, and other clinical information can be used for differential diagnosis. Once the diagnosis of an ISH is made, management consists of a neurosurgical consultation for possible parasagittal craniotomy (3,5,8,14) sinceburrhole aspiration is unlikely to result in complete drainage of the clot (15). If the patient’s condition is stable and there is a small hematoma without mass effect, conservative measuresmay be adequate(4,16). CONCLUSIONS An ISH is still a rare finding in adults with head trauma but should always be considered in a patient of any age with severehead shaking, occipital or vertex head trauma, delayed focal neurological abnormalities presenting as a falx syndrome, and focal lower extremity seizure activity. At this time, the advantages of MRI, even high speed MRI, over CT scans for intracranial bleeds remains to be demonstrated. A CT scan also allows visualization of the bony anatomy, which is very important and more practical in the emergency setting of acute head trauma. An MRI scan may help confirm a structural lesion, even blood, if the CT scan is inconclusive or nondiagnostic.
REFERENCES 1. Zimmerman RA, Bihtnuik LT, Bruce D, et al. Interhemispheric acute subdural hematoma: A computed tomographic manifestation of child abuse by shaking. Neuroradiology. 1978;16:39-40. 2. Zimmerman RA, Bilanuik LT, Bruce D, et al. Computed tomography of craniocerebral injury in the abused child. Radiology. 1979;130:687-90. 3. Toffol GJ, Biller J, Adams, Jr, HP: Interhemispheric subdural hematoma. J Emerg Med. 1986;4:104-7. 4. Gartman JJ, Atstupenas ISA, Vollmer DE, Powers SK. Traumatic laceration of pericallosal artery resulting in interhemispheric subdural hematoma: A case report. J Emerg Med. 1989;7:603-10. 5. Fruin AH, Juhl GL, Taylon C. Interhemispheric subdural hematoma. Case report. J Neurosurg. 1984;60:1300-2. 6. Glista GG, Reichman HO, Brumlik J, Fine M. Interhemispheric subdural hematoma. Surg Neurol. 1979;10:119-22. 7. Ogsbury JS, Schneck SA, Lehman RA. Aspects of interhemi-
spheric subdural hematoma, including the falx syndrome. J Neurol Neurosurg Psychiatry. 1978;41:72-5. 8. Pozzati E, Gaist G, Vinei A, Poppi M. Traumatic interhemispheric subdural hematoma. J Trauma. 1982;22:241-3. 9. Ho SU. Snehlmann R. Ho HT. CT scan in interhemisnheric subdural hematoma. ‘Clinical and pathological correlation. Neurology. 1977;27:1097-8. 10. Zimmerman RA, Russell EJ, Yaberg E, et al. Falx and interhemispheric fissue on axial CT: II. Recognition and differentiation of interhemispheric subarachnoid and subdural hemorrhage. AJNR. 1982;3:635-42. 11. Williams KD. Draver BP. Bird CR. Masmetic resonance imaging in the diagnosis of intracerebral hematoma. BNI Quarterly. 1989;5(1):16-23. 12. Thulborn KR, Atlas SW. Intracranial hemorrhage. In: Atlas SW, ed. Magnetic resonance imaging of the brain and spine. New York: Raven Press;1991:175-222. 13. Atlas SW. MR imaging of intracranial hemorrhage. Neurora-
Interhemispheric Subdural Hematoma on MRI diology section Department of Radiology, Hospital of University of PA, Philadelphia, PA. 14. Esposito DP, Devkota J, El Gammal T, Sullivan HG. Interhemispheric subdural hematoma. Case report. South Med J. 1984;77:379-81.
373 15. Fearnside MR, Hall K, Sengupta RP. Interhemispheric subdural hematoma following head injury. Aust NZ J Surg. 1979; 49:678-80. 16. Russell NA, de1Carpio-G’Donovan R, Mallya KB, et al. Interhemisphericsubdural hematoma.Can J Nemo1Sci.I 987;14:1724.
Pergamon
0736~4679/94$6.00 + 30
-----
s4Bkctd TbpkS
Emtwgency
Radiology
CONFMWHATION OF TRAUMATIC INTERtlEMIBPHERIC SUBDURAL W fMATOMA BY MAGNETIC RESONANCE tAllAGING Valerie A. Romano, DO, and Gilbert J. Toffol, DO Depaltment of Internal Medicine, Division of Neurology, Mesa General Hospital Medical Center, Mesa, Arizona Reprint Address: Gilbert J. Toffol, DO, 4244 North 19th Avenue, Phoenix, AZ 85015
[I Abstract- We report a case of interhemispheric subdural hematoma following closed head injury producing contralateral neurological findings and focal seizures. Noncontrast cranial computed tomography scan was initiaily reported to be normai, but magnetic resonance imaging of the brain demonstrated an interhemispheric subdural hemstoma. Head injury, specifically occipital, is the leading cause of interhemispheric subdural hematoma in adults. Most patients develop a “falx syndrome.” If adequately interpreted, magnetic resonance imaging of the brain showing the appearance of blood on Tl- and T2weighted images can detect interhemispheric subdural hematoma. However, computed tomography scan should always be done first to detect intercranial bleeding, and it should be performed with and without contrast in patients with prior head trauma and delayed bleeds.
mental status changes,and contralateral isolated paresis of one leg or hemiparesis,worse in the leg than the arm, the so called “falx syndrome”(4). We report a caseof an elderly lady who presentedto Mesa General Hospital’s Emergency Department with a falx syndrome and focal motor seizures due to head trauma secondaryto an ISH. Magnetic resonanceimaging (MRI scan) confirmed the diagnosis after the initial CT scanwas reported to be unremarkable.We discuss the abnormalities of Tl- and TZ-weighted MR imagesthat help confirm the presenceof blood, since MRI is not often used for acute trauma or bleeds in the emergency department. This lesion needsto be sought in adults as well as children.
7 Keywords - hematoma; falx syndrome; trauma; imaging; craniotomy
CASE REPORT
Two weeksprior to admission,an 80-year-oldwoman with hypertension sustained a head injury. The patient slipped and hit the occipital region of her head against the wall with force great enough to create a hole in the plaster. There was no loss of consciousness,and the patient experiencedno immediate effects. On the day of admission, the patient, on examination, had left-sided weaknesspredominantly affecting the leg and sparing the face (falx syndrome) and focal motor seizureactivity of the left leg with a
INTRODUCTION
Traumatic interhemisphericsubduralhematoma(ISH) is commonly seenin abusedchildren who have suffered severehead shaking (1,2) and rarely occurs in adults (3). An ISH is usually diagnosedby history and physical examination and confirmed by computed tomography (CT scan). Clinical findings suggestiveof ISH include paraparesis,seizures,delayed
Radiology-This sectionof JEM containsarticlesof interestandoriginalresearch related to emergency radiology and is coordinated by Jock Keene, MD, of St. Francis Hospital, Poughkeepsie, New York. RECEIVED: 30 December1992;FINAL SUBMISSIONRECEIVED: 28 September1993; ACCEPTED:
8 October 1993
369
370
Valerie A. Roman0 and Gilbert J. Toffol
Jacksonian march to the left arm. This was treated initially with IV diazepam and later with phenytoin. A noncontrast CT scan of the head (Figure 1) was initially reported to be unremarkable. An electroencephalogram (EEG) showed cortical irritability compatible with seizure tendency in the right hemisphere. An MRI was obtained 2 days later to rule out a structural lesion, and it showed a subacute falx subdural hematoma or ISH (Figures 2 and 3). The patient was discharged on phenytoin, and physical therapy provided gait training and ambulation. DISCUSSION An ISH is a rare finding that generally occurs following trauma. A history of loss of consciousnessor evidence of skull fracture is not usually associated with an ISH (5). Several studies have shown the site of trauma to be the occipital region (5-7). A sharp blow to the occiput causes posterior movement of the cerebral hemisphererelative to the fixed superior sagittal sinus. This maximally stretches the veins, leading to an increased risk of tearing. The mechanism of production of the hematoma is likely to be a rotational injury with shearing of the bridging veins between the medial border of the cerebral hemisphere and the sinus. The hematoma remains in the interhemispheric region due to the adherenceof the arachnoid trabeculations between the brain and the parasagittal dura.
Figure 1. Noncontrast CT scan showlng an ill-defined linear hypodenslty along the right parasaglttal cerebral hemlsphere. In retrospect, there is lnterhemispherlc hyperdenslty.
Figure 2A. Coronal Tl-weighted MRI Image showing an abnormal hyperlntense signal along the right side of the falx cerebri.
Hemiparesis, worse in the lower than the upper extremity (falx syndrome), or lower extremity monoparesis is characteristic of the ISH lesion (6). Other symptoms of an ISH include vomiting, lethargy, headache, seizures, and mental status changes (3,5,6). An ISH often has a subacute or chronic course with the onset of focal neurologic signs appearing more than 48 hours after the injury (8). The falx syndrome is also produced by other causes.The differential diagnosis includes occlusion of an anterior cerebral artery, interhemispheric empyema, and anterior communicating artery aneurysm with subarachnoid hemorrhage (3,6). Both interhemispheric empyema and subdural hematoma produce the falx syndrome due to a mass effect (7). Diagnosis of an ISH should be considered whenever a CT scan shows the image of a hematoma near the m idline with a flat broad base attached to the falx with a convex lateral border (9). The hematoma also frequently extends along the leaflet of the tentorium cerebelli (10). The CT scan is an excellent modality for diagnosis of an ISH; however, the CT scan occasionally will not reveal a subacute or chronic hematoma, unless the study is made with and without contrast (11). Another causefor a false negative non-
Interhemispheric Subdural Hematoma on MRI
Flgure 28. Sagittal Tl-weighted toma.
371
MRI image showing the abnormal hyperintense slgnal compatible with a falx subdural hema-
Figure 3A. Axlal Tl-weighted MRI image showing a hyperintense slgnal atong the right side of the falx cerebri.
Figure 38. Axial T2-wetghM #&RI image also showing a hyperlntense tdgnel compatible with the dkgneals of a subacute bleed.
372
Valerie A. Roman0 and Gilbert J. Toffol
contrast CT scan in the presence of subacute or chronic subdural hematomas is a hematocrit less than 20%. Contralateral paresis of the lower extremity out of proportion to the arm and face may provide a clue to the location of the lesion. Therefore, an unremarkable CT scan, along with the clinical manifestation of a falx syndrome, should warrant an MRI scan. In retrospect, our patient’s noncontrast CT scan was abnormal and should have been interpreted as suggesting the possibility of an interhemispheric collection of isodenseblood. Any imaging modality used for diagnosing central nervous system (CNS) disorders should detect or exclude hemorrhage with a high degree of accuracy if properly interpreted. The MRI scan is a very sensitive and specific technique for diagnosing intracranial bleed, except for subarachnoid hemorrhage (12). Acute, subacute, and chronic stages of blood can be identified by characteristic appearances of deoxyhemoglobin, methemoglobin, and hemosiderin, respectively, on an MRI scan (11). Changes in signal intensity associated with hemorrhage are generally opposite those accompanying most CNS pathologies. For reference in viewing MRI studies, normal cerebrospinal fluid (CSF) appears dark or black (low signal intensity) on Tl-weighted images and bright or white (high signal intensity) on T2-weighted images. The so-called intermediate weighted or proton density study has the CSF appearing gray, similar to the brain parenchyma signal. Tissues with short Tl relaxation times appear bright on Tl-weighted images and include fat, subacute hemorrhage (methemoglobin), and enhancing tissue (gadolinium) (12). Tissues with short T2 relaxation times appear dark, and these include acute hematoma (less than 7 days old), hemosiderin-laden macrophages, and ferritin (12). Therefore, areas of high signal intensity on Tlweighted images and low signal intensity on T2-
weighted images may indicate acute hemorrhage (11). Subacute (between 1 week and a month old) intraparenchymal or subdural hematomas have high signal intensities seen on both Tl- and T2-weighted images (13). Chronic hematomas (more than a month old) may have several appearances on TZweighted images, but usually TZweighted images show a high intensity lesion surrounded by a thin rim of low signal intensity representing hemosiderin deposition around the bleed (13). Once a lesion has been characterized as a hematoma, location, patient age, and other clinical information can be used for differential diagnosis. Once the diagnosis of an ISH is made, management consists of a neurosurgical consultation for possible parasagittal craniotomy (3,5,8,14) sinceburrhole aspiration is unlikely to result in complete drainage of the clot (15). If the patient’s condition is stable and there is a small hematoma without mass effect, conservative measuresmay be adequate(4,16). CONCLUSIONS An ISH is still a rare finding in adults with head trauma but should always be considered in a patient of any age with severehead shaking, occipital or vertex head trauma, delayed focal neurological abnormalities presenting as a falx syndrome, and focal lower extremity seizure activity. At this time, the advantages of MRI, even high speed MRI, over CT scans for intracranial bleeds remains to be demonstrated. A CT scan also allows visualization of the bony anatomy, which is very important and more practical in the emergency setting of acute head trauma. An MRI scan may help confirm a structural lesion, even blood, if the CT scan is inconclusive or nondiagnostic.
REFERENCES 1. Zimmerman RA, Bihtnuik LT, Bruce D, et al. Interhemispheric acute subdural hematoma: A computed tomographic manifestation of child abuse by shaking. Neuroradiology. 1978;16:39-40. 2. Zimmerman RA, Bilanuik LT, Bruce D, et al. Computed tomography of craniocerebral injury in the abused child. Radiology. 1979;130:687-90. 3. Toffol GJ, Biller J, Adams, Jr, HP: Interhemispheric subdural hematoma. J Emerg Med. 1986;4:104-7. 4. Gartman JJ, Atstupenas ISA, Vollmer DE, Powers SK. Traumatic laceration of pericallosal artery resulting in interhemispheric subdural hematoma: A case report. J Emerg Med. 1989;7:603-10. 5. Fruin AH, Juhl GL, Taylon C. Interhemispheric subdural hematoma. Case report. J Neurosurg. 1984;60:1300-2. 6. Glista GG, Reichman HO, Brumlik J, Fine M. Interhemispheric subdural hematoma. Surg Neurol. 1979;10:119-22. 7. Ogsbury JS, Schneck SA, Lehman RA. Aspects of interhemi-
spheric subdural hematoma, including the falx syndrome. J Neurol Neurosurg Psychiatry. 1978;41:72-5. 8. Pozzati E, Gaist G, Vinei A, Poppi M. Traumatic interhemispheric subdural hematoma. J Trauma. 1982;22:241-3. 9. Ho SU. Snehlmann R. Ho HT. CT scan in interhemisnheric subdural hematoma. ‘Clinical and pathological correlation. Neurology. 1977;27:1097-8. 10. Zimmerman RA, Russell EJ, Yaberg E, et al. Falx and interhemispheric fissue on axial CT: II. Recognition and differentiation of interhemispheric subarachnoid and subdural hemorrhage. AJNR. 1982;3:635-42. 11. Williams KD. Draver BP. Bird CR. Masmetic resonance imaging in the diagnosis of intracerebral hematoma. BNI Quarterly. 1989;5(1):16-23. 12. Thulborn KR, Atlas SW. Intracranial hemorrhage. In: Atlas SW, ed. Magnetic resonance imaging of the brain and spine. New York: Raven Press;1991:175-222. 13. Atlas SW. MR imaging of intracranial hemorrhage. Neurora-
Interhemispheric Subdural Hematoma on MRI diology section Department of Radiology, Hospital of University of PA, Philadelphia, PA. 14. Esposito DP, Devkota J, El Gammal T, Sullivan HG. Interhemispheric subdural hematoma. Case report. South Med J. 1984;77:379-81.
373 15. Fearnside MR, Hall K, Sengupta RP. Interhemispheric subdural hematoma following head injury. Aust NZ J Surg. 1979; 49:678-80. 16. Russell NA, de1Carpio-G’Donovan R, Mallya KB, et al. Interhemisphericsubdural hematoma.Can J Nemo1Sci.I 987;14:1724.