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Diffuse dural enhancement
ELSEVIER
Imaging Tip of the Month
DIFFUSE
DURAL
ENHANCEMENT
CASEHISTORY A previously healthy 36-year-old man developed sudden severe head and neck pain during heavy lifting. His discomfort was made worse by standing and was relieved by lying down. Neurologic examination and a cranial computed tomography (CT) scan with and without enhancement were normal. The spinal fluid contained a few lymphocytes and mildly elevated protein. Cervical magnetic resonance imaging (MRI) showed dural enhancement in the posterior fossa and upper cervical area (Figure 1). Because he failed to improve with symptomatic treatment, another imaging study was performed several weeks later, which confirmed the clinical diagnosis.
with this condition may be misled into searching for an occult neoplasm or infection. SIH is usually self-limiting and may respond to simple analgesics containing caffeine. If necessary, an epidural blood patch is usually curative. Benjamin Kuzma, M.D. Julius M. Goodman, M.D.
Indianapolis,
Indiana
REFERENCES 1. Fishman RA, Dillon WP. Dural enhancement and cerebral displacement secondary to intracranial hypotension. Neurology 1993;43:609-11. 2. Kosmorsky GS. Spontaneous intracranial hypotension. J Neuroophthamol 1995;15:79-83.
DISCUSSION On a routine MRI scan, normal dura is isointense to cortical bone and hence is nearly invisible, except for the falx cerebri, tentorium, and dural sinus. With contrast, small segments of dura usually enhance, particularly near the superior sagittal sinus. Extensive dural enhancement and apparent dural thickening may occur in a variety of diseases that involve the meninges, such as meningitis, meningeal carcinomatosis, and sarcoidosis. Dramatic diffuse dural enhancement may also occur without direct involvement by a pathologic process, such as following craniotomy, intrathecal chemotherapy, shunt placement, and even after a single lumbar puncture. This case illustrates dural enhancement in spontaneous intracranial hypotension (%-I). The diagnosis was confirmed by an isotope cisternogram, which showed tracer accumulation in the left upper thoracic paraspinal area. A MRI through this area showed anterior extradural fluid, which was felt to have originated in a ruptured nerve root cyst. Other MRI findings sometimes seen with SIH are an acquired Chiari I malformation, downward displacement of the optic chiasm, flattening of the pons against the clivus, effacement of the suprasellar, chiasmal, interpeduncular, and prepontine cisterns, and subdural effusion. This dural enhancement is usually not apparent on contrast CT scans. The reason for the enhancement has not been determined with certainty. Because spinal fluid in SIH may contain a few cells and mildly elevated protein, clinicians not familiar 0 1996 by Elsevfer Science Inc. 655 Avenue of the Americas, New York,
NY 10010
Cervical MRI (sog&ol uiew) reveals dural enhancement in the posterior fossa and upper cervical area (Q?YOWS).
0090-3019/96/$15.00 PII SOO90-3019(96)00160-7
Imaging Tip of the Month
DIFFUSE
DURAL
ENHANCEMENT
CASEHISTORY A previously healthy 36-year-old man developed sudden severe head and neck pain during heavy lifting. His discomfort was made worse by standing and was relieved by lying down. Neurologic examination and a cranial computed tomography (CT) scan with and without enhancement were normal. The spinal fluid contained a few lymphocytes and mildly elevated protein. Cervical magnetic resonance imaging (MRI) showed dural enhancement in the posterior fossa and upper cervical area (Figure 1). Because he failed to improve with symptomatic treatment, another imaging study was performed several weeks later, which confirmed the clinical diagnosis.
with this condition may be misled into searching for an occult neoplasm or infection. SIH is usually self-limiting and may respond to simple analgesics containing caffeine. If necessary, an epidural blood patch is usually curative. Benjamin Kuzma, M.D. Julius M. Goodman, M.D.
Indianapolis,
Indiana
REFERENCES 1. Fishman RA, Dillon WP. Dural enhancement and cerebral displacement secondary to intracranial hypotension. Neurology 1993;43:609-11. 2. Kosmorsky GS. Spontaneous intracranial hypotension. J Neuroophthamol 1995;15:79-83.
DISCUSSION On a routine MRI scan, normal dura is isointense to cortical bone and hence is nearly invisible, except for the falx cerebri, tentorium, and dural sinus. With contrast, small segments of dura usually enhance, particularly near the superior sagittal sinus. Extensive dural enhancement and apparent dural thickening may occur in a variety of diseases that involve the meninges, such as meningitis, meningeal carcinomatosis, and sarcoidosis. Dramatic diffuse dural enhancement may also occur without direct involvement by a pathologic process, such as following craniotomy, intrathecal chemotherapy, shunt placement, and even after a single lumbar puncture. This case illustrates dural enhancement in spontaneous intracranial hypotension (%-I). The diagnosis was confirmed by an isotope cisternogram, which showed tracer accumulation in the left upper thoracic paraspinal area. A MRI through this area showed anterior extradural fluid, which was felt to have originated in a ruptured nerve root cyst. Other MRI findings sometimes seen with SIH are an acquired Chiari I malformation, downward displacement of the optic chiasm, flattening of the pons against the clivus, effacement of the suprasellar, chiasmal, interpeduncular, and prepontine cisterns, and subdural effusion. This dural enhancement is usually not apparent on contrast CT scans. The reason for the enhancement has not been determined with certainty. Because spinal fluid in SIH may contain a few cells and mildly elevated protein, clinicians not familiar 0 1996 by Elsevfer Science Inc. 655 Avenue of the Americas, New York,
NY 10010
Cervical MRI (sog&ol uiew) reveals dural enhancement in the posterior fossa and upper cervical area (Q?YOWS).
0090-3019/96/$15.00 PII SOO90-3019(96)00160-7