Hemorrhagic arachnoid cyst with third nerve paresis: CT and MR findings

We report the CT and MR appearance of a nontraumatic hemorrhagic arachnoid cyst presenting with a third nerve paresis in a 37-year-old man. The cyst, located in the left suprasellar area, contained a fluid-blood level with stigmata of subacute hemorrhage on both CT and MR studies.     

Arachnoid cyst rupture producing subdural hygroma and intracranial hypertension: case reports

OBJECTIVE: To analyze the association between arachnoid cysts and subdural hygromas. METHODS: We reviewed five cases of arachnoid cysts that ruptured, producing acute subdural hygromas. The surgical management and diagnostic methods used are assessed. RESULTS: Five male patients ranging in age from 6 to 25 years sustained the rupture of arachnoid cysts, which produced acute subdural hygromas. Four of the patients had incurred blunt head trauma. All patients presented with symptoms referable to intracranial hypertension. The pathognomonic features of a middle fossa arachnoid cyst (MFAC) were noted on the computed tomographic scans and/or magnetic resonance images of each patient. The hygroma exerted mass effect on the ipsilateral hemisphere and was noted to be under significant pressure at the time of surgical intervention in each case. Two of the five cases are unique in the literature. In one, a coexisting quadrigeminal cyst ruptured, producing a subdural hygroma ipsilateral to the MFAC and dilating the basal cisterns. In the other, the MFAC ruptured into the basal cisterns as well as into the subdural space. The MFAC in each of the remaining three patients ruptured into the subdural space alone. All patients were treated with drainage of the subdural space. In the two patients in whom the basal cisterns were involved, both the hygromas and the MFACs failed to change significantly in size. The hygromas resolved completely and the MFACs decreased in size considerably in the three patients without cisternal involvement. CONCLUSION: The rupture of an arachnoid cyst can produce a subdural hygroma and intracranial hypertension. The latter mandates emergent drainage of the subdural space. In patients in whom the basal cisterns are not dilated by cyst rupture, both the MFACs and hygromas resolve after subdural drainage.     

Subdural hematoma associated with arachnoid cyst

We describe 3 young patients with history of mild cranial trauma who presented the rare association of subdural hematoma and arachnoid cyst. Clinical and radiological signs are reviewed.     

Spinal subdural enhancement after suboccipital craniectomy

PURPOSE: To characterize transient intraspinal subdural enhancement (potentially mimicking the subarachnoid spread of tumor) seen on MR images in some children after suboccipital craniectomy for posterior fossa tumor resection. METHODS: Radiologic and medical records of 10 consecutive children who had MR imaging for spinal staging after resection of posterior fossa tumor during a 9-month period were reviewed retrospectively. In addition, one case with similar findings of intraspinal enhancement on spinal staging MR images obtained at another institution was included in the review. RESULTS: Intraspinal enhancement thought to be subdural was seen in four of 10 patients undergoing spinal staging MR imaging 6 to 12 days after surgery. In these four patients, MR studies 50 to 18 days later, without intervening treatment, showed resolution of the abnormal enhancement. A fifth patient (from another institution) with similar intraspinal enhancement underwent CT myelography 4 days later, which showed no subarachnoid lesions. No metastases have developed in any of these five patients during the 2.5- to 3.5-year follow-up period. conclusions: From analysis of the MR appearance and on the basis of prior myelographic experience, we suggest an extraarachnoid, probably subdural, location of this enhancement. Awareness of this phenomenon will reduce the rate of false-positive diagnoses of metastatic disease. Preoperative spinal staging should be considered for patients undergoing suboccipital craniectomy.     

Resection of liver metastasis from alpha-fetoprotein-producing early gastric cancer: report of a case

Compression of the crus cerebri against the free edge of the tentorium contralateral to a supratentorial mass, the so-called Kernohan's notch, can be a cause of false localizing sign. Kernohan's notch has been thoroughly studied clinically and pathologically, but not radiographically. The authors describe a case of left chronic subdural hematoma, which resulted in left hemiparesis caused by Kernohan's notch. Injury to the contralateral cerebral peduncle was clearly shown by magnetic resonance imaging (MRI) performed in the postoperative period. A 43-year-old man was transferred to our hospital in deep coma with dilated pupils, unreactive to light. Computed tomography (CT) scans obtained on admission revealed a left chronic subdural hematoma and a midline shift to the right. After drainage and irrigation of the left chronic subdural hematoma through a single burr hole, his clinical condition improved gradually. But 1 month after the operation, mild left hemiparesis still persisted. MRI T2-weighted images demonstrated an abnormally increased signal area in the right cerebral peduncle. T1-weighted coronal images showed the anatomical relationship between the hypointense lesion in the right cerebral peduncle and tentorial edge. Three-dimensional-MRI (3D-MRI) clearly demonstrated the surface image of Kernohan's notch. We emphasize the utility of 3D-MRI for detecting evidence of brain stem injury, such as Kerno han's notch.     

A resolving sign of acute subdural hematoma: from report of two cases

A 7-year-old-boy (Case 1) and a 60-year-old-man (Case 2) presented with rare spontaneous resolution of acute subdural hematoma (ASDH). They were admitted with consciousness disturbance, drowsy in Case 1 and sleepy in Case 2. Initial CT showed ASDH associated with a low density band between the hematoma and the inner wall of the skull base, combined with right parietal contusion in Case 2. Repeat CT showed that the hematoma had resolved spontaneously after a few hours, and the patients regained clear consciousness next day in Case 1 within a few days in Case 2 without surgical treatment. The mechanism of spontaneous resolution of ASDH was thought to involve pulsatile flow of cerebrospinal fluid (CSF) through the tear in the arachnoid membrane, resulting in redistribution and dispersal of the hematoma, and retrograde flow into the subarachnoid space. The characteristic feature of the CT findings, the low density band between the hematoma and the inner wall of the skull bone, probably shows this process. Spontaneous resolution of ASDH requires that the brain compensatory function maintains the normal outflow of CSF, and controls the intracranial pressure by CSF buffering, blood outflow via the venous system, and brain elasticity. The low density band may be a useful finding to distinguish cases with good and bad prognosis.     

Transcutaneous pressure adjustable valve for the treatment of hydrocephalus and arachnoid cysts in adults. Experiences with 75 cases

The authors report a series of 75 adults treated over the last four years for hydrocephalus (69 cases) or arachnoid cysts (6 cases) by using a transcutaneous pressure adjustable valve (Sophy SU 8), the mechanism of which is recalled. The shunt was ventriculo-atrial 46 times, ventriculo-peritoneal 23 times and cysto-peritoneal 6 times. The opening pressure of the valve was initially adjusted 56 times to the medium, 9 times to the high, and 10 times to the low position, according to each particular patient's needs. Following the evolution of the neurological status and/or the CT findings, the opening pressure was secondarily modified in 27 patients (i.e., in 36%), and in some of them several times. It was raised 16 times: 10 times because of subdural hygroma(s) (complicated by a subdural haematoma which required surgical removal, in one case), and 6 times because of clinical symptoms of intracranial hypotension associated with hyperdrainage signs on CT. It was diminished 20 times because of the absence of clinical improvement and persistence of dilated ventricles on CT. In these 27 patients the Sophy SU 8 valve allowed modification of its opening pressure according to the clinical and CT evolution, without need for re-operation. It is concluded that the patients who can benefit most from this valve system are patients with normal pressure hydrocephalus or with arachnoid cysts.     

Repair of traumatic orbital wall defects with nasal septal cartilage: report of five cases

PURPOSE: Arachnoid cysts are sometimes encountered in MRIs performed for a variety of reasons. In patients with epilepsy, particularly those with refractory epilepsy, arachnoid cysts are often assumed to be related to their seizure focus. We conducted a study to investigate this putative relationship. METHODS: A retrospective study on the incidence of arachnoid cysts was performed in patients seen in our Epilepsy Clinic who had CT or MRI scans, interictal EEGs or ictal EEGS. Locations of seizure foci in these patients were defined from clinical and electrophysiologic data. RESULTS: Seventeen of 867 patients had arachnoid cysts. Twelve patients had temporal lobe cysts and only 3 of them had temporal lobe seizures. Four patients had frontal lobe cysts and only 1 had frontal lobe seizures ipsilateral to the cyst. One patient had a cerebello-pontine angle cyst and frontal lobe seizures. Thus, clinical manifestations of seizures and EEG findings (interictal and/or ictal) indicated that the seizure focus was adjacent to the cysts in only 4 patients (23.5%). CONCLUSIONS: Our findings suggest that arachnoid cysts are often an incidental finding in patients with epilepsy and do not necessarily reflect the location of the seizure focus.     

Magnetic resonance imaging-documented extravasation as an indicator of acute hypertensive intracerebral hemorrhage

OBJECT: The aim of this study was to determine the usefulness of magnetic resonance (MR) imaging-documented extravasation as an indicator of continued hemorrhage in patients with acute hypertensive intracerebral hemorrhage (ICH). METHODS: The authors studied 108 patients with acute hyperintensive ICH. Imaging modalities included noncontrast-enhanced computerized tomography (CT) scanning, gadolinium-enhanced MR imaging, and conventional cerebral angiography obtained within 6 hours after the onset of hemorrhage. A repeated CT scan was obtained within 48 hours to evaluate enlargement of the hematoma. Findings on MR imaging indicating extravasation, including any high-intensity signals on T1-weighted postcontrast images, were observed in 39 patients, and 17 of these also showed evidence of extravasation on cerebral angiography. The presence of extravasation on MR imaging was closely correlated with evidence of hematoma enlargement on follow-up CT scans (p < 0.001). CONCLUSIONS: Evidence of extravasation documented on MR imaging indicates persistent hemorrhage and correlates with enlargement of the hematoma.     

Arachidonate-induced tyrosine phosphorylation of epidermal growth factor receptor and Shc-Grb2-Sos association

PURPOSE: Subdural grid arrays are used when seizure activity cannot be located by ictal scalp recordings and when functional cortical mapping is required before surgery. This study was performed to determine and compare the CT and MR imaging appearance of subdural EEG grids and to identify the types and frequency of associated complications. METHODS: We retrospectively reviewed the medical records and imaging studies of 51 consecutive patients who underwent 54 craniotomies for subdural EEG grid implantation with either stainless steel or platinum alloy contacts between June 1988 and September 1993. Twenty-two patients had both CT and MR examinations, 27 patients had CT only, and five patients had MR imaging only. All studies were assessed for image quality and degradation by the implanted EEG grids, for intra- and extraaxial collections, and for mass effect, with differences of opinion resolved by consensus. RESULTS: Subdural EEG grids caused extensive streak artifacts on all CT scans (corresponding directly to grid composition) and mild to moderate magnetic susceptibility artifacts on MR images. Sixteen associated complications were detected among the 54 patients imaged, including four significant extraaxial hematomas, four subfalcine or transtentorial herniations, two tension pneumocephali, two extraaxial CSF collections, two intraparenchymal hemorrhages, and one case each of cerebritis and brain abscess. In all but four cases, the detected complications were not clinically apparent and did not require specific treatment. There were no residual sequelae. CONCLUSION: Because of extensive streak artifacts, CT showed only gross complications, such as herniation and grid displacement by extraaxial collections. MR imaging artifacts were more localized, allowing superior evaluation of subdural EEG grid placement and associated complications.     

Dental health amongst 11-15-year-old children in Sevagram, Maharashtra

Although most subdural hematomas are considered to be venous in origin, they may also be of arterial origin. When subdural bleeding is due to the rupture of an intracranial aneurysm, most commonly at the middle cerebral or internal carotid arteries, the amount of subdural blood is usually small and of no clinical importance. We describe two patients with subdural hematomas secondary to rupture of an intracranial aneurysm, who needed prompt surgical treatment. The first patient had a left internal carotid artery aneurysm at the origin of the ophthalmic artery. In the second patient the aneurysm was at the anterior communicating artery and rebled into the subdural space directly through a right intraparenchymatous frontobasal hematoma. The most probable mechanism of subdural bleeding in our two patients was the existence of adhesions between the aneurysm and the arachnoid due to previous minor hemorrhages. The indication of cerebral angiography in a patient with subdural hematoma is based mainly upon the existence of meningeal signs, the presence of blood in more than one intracranial compartment or the rapid progression of bleeding.     

Unco-parahippocampectomy for direct surgical treatment of downward transtentorial herniation

Downward transtentorial herniation is a major cause of death and disability caused by acute supratentorial mass lesions. Thirteen patients, 7 men and 6 women aged from 23 to 75 years old, with progressive transtentorial herniation caused by cerebral contusion with acute subdural haematoma, acute brain swelling after aneurysmal subarachnoid haemorrhage, or massive cerebral infarction were treated by direct surgery using selective removal of the uncus and parahippocampal gyrus (unco-parahippocampectomy). All patients showed progressive deterioration of transtentorial herniation (late third nerve stage or midbrain stage) with unilateral pupillary dilation and absent light reflex. Preoperative Glasgow Coma Scale scores ranged from 4 to 8. Unco-parahippocampectomy was performed via the middle temporal gyrus under the operating microscope. The oculomotor nerve, posterior cerebral artery, and midbrain were directly decompressed. Incision of the arachnoid membrane in the tentorial incisura allowed free communication of the cerebrospinal fluid between the supra- and finfra-cranial fossae to reduce the pressure gradient. Two of the 13 patients died (15%). Two of the 11 survivors (18%) were functionally independent and 1 (9%) required minimal assistance but was independent at home. This series suggests the lifesaving nature of unco-parahippocampectomy in patients with deteriorating clinical condition because of transtentorial herniation.     

CT and MR in infants with pericerebral collections and macrocephaly: benign enlargement of the subarachnoid spaces versus subdural collections

PURPOSE: To compare CT and MR in the differentiation of benign enlargement of the subarachnoid spaces and subdural collections in infants with macrocephaly. METHODS: MR was performed in 19 infants with macrocephaly, showing bifrontal enlargement of the subarachnoid spaces on CT. RESULTS: In 11 patients, a single fluid layer could be distinguished on MR of the pericerebral collections, suggesting benign enlargement of the subarachnoid spaces. In eight patients, two separate layers were clearly differentiated, an outer layer that was hyperintense on all sequences and an inner layer with the same intensity as the cerebrospinal fluid. This indicated the presence of subdural collections. These collections were mainly frontal in six and extended over the entire hemisphere in two patients. On CT, these separate lesions were seen only in three patients and missed in three others. In two final patients, CT findings were equivocal with evidence of membrane formation within the hypodense collections. In seven patients with a subdural collection, subdural-external drainage was performed. In three patients, the collection was hemorrhagic. The protein content of the fluid showed a mean of 1381.7 +/- 785.6 mg/dL. The MR and surgical findings of a subdural collection correlated with the absence of a family history of macrocrania, an age under 5 months, and acute clinical signs of vomiting, somnolence, and hypotonia. CONCLUSION: MR appears essential in the differential diagnosis between benign enlargement of the subarachnoid spaces and subdural collections in infants.     

Petrous apex arachnoid cyst: radiographic confusion with primary cholesteatoma

The advent of combined computed tomography (CT) and magnetic resonance imaging (MRI) for the evaluation of petrous apex lesions has improved the otologist's ability to differentiate among many disease processes. Temporal bone CT details osseous anatomy, whereas MRI delineates soft tissue signal characteristics. The employment of these two imaging modalities is often successful in differentiating between cholesterol common entities encountered in the petrous apex. The finding of a smoothly marginated, expansile, bone eroding lesion on CT, coupled with hypointensity on T1-weighted and hyperintensity on T2-weighted images on MRI, is highly suggestive of cholesteatoma. The authors recently encountered two cases of arachnoid cyst involving the petrous apex that shared the same imaging features seen with the more common cholesteatoma. One patient presented with tic douloureux, whereas the other had a spontaneous transotic cerebrospinal fluid leak. The contemporary skull base surgeon should include arachnoid cyst as a rare possibility in the evaluation and treatment of petrous apex lesions.     

The normal and pathologic ischiorectal fossa at CT and MR imaging

A wide spectrum of disease processes involve the ischiorectal fossa, including congenital and developmental lesions; inflammatory, traumatic, and hemorrhagic conditions; primary tumors; and pathologic processes outside the ischiorectal fossa with secondary involvement. Both computed tomography (CT) and magnetic resonance (MR) imaging are useful in the definitive diagnosis of these pathologic conditions, with MR imaging being the modality of choice because of its superior contrast resolution and multiplanar capability. In Gartner duct cyst, both CT and MR imaging demonstrate a well-defined, round mass; in tailgut cyst, CT demonstrates a well-defined retrorectal mass with a solid or cystic appearance. MR imaging in particular plays a major role in the assessment of fistula in ano, infection, and hematoma. Lipoma and pelvic plexiform neurofibroma typically have low attenuation and high signal intensity at CT and MR imaging, respectively. Recurrent rectal tumor appears at both modalities as an irregular soft-tissue mass with or without central necrosis in the presacral space, perineum, or pelvic sidewall. Familiarity with the imaging features and differential diagnoses of various ischiorectal pathologic processes will facilitate prompt, accurate diagnosis and treatment.     

Comparing the severity of obstructive sleep apnea in patients referred by urban and rural physicians

The occurrence of a subdural hematoma caused by the rupture of an intracranial aneurysm is rare. In our case, the patient is a 43-year-old woman who suffered from sudden onset of severe headache. Computed tomographic (CT) scan disclosed a subdural hematoma associated with subarachnoid hemorrhage. CT angiography and digital subtraction angiography revealed an elongated aneurysm adhering to the dura in the left Sylvian fissure. The subdural hematoma was evacuated and the aneurysm clipped. The patient made a full recovery.     

Comparison of radiography, computed tomography and magnetic resonance imaging in the detection of sacroiliitis accompanying ankylosing spondylitis

OBJECTIVE: To compare magnetic resonance (MR) imaging, computed tomography (CT), and radiography in the detection of sacroiliitis accompanying ankylosing spondylitis (AS). DESIGN AND SUBJECTS: Nine volunteers and 24 patients were recruited. Radiography, CT, and MR imaging were completed within a 1-week period in 24 patients with AS. In precontrast MR examination, spin-echo T1, fast spin-echo T2, and gradient echo with rephasing T2* images were obtained without fat saturation using a 0.3-T imager for all volunteers and patients. Postcontrast MR examination was performed using the same precontrast SE T1 sequence for patients with AS. RESULTS AND CONCLUSIONS: MR imaging directly showed the normal cartilage in all 16 sacroiliac joints of the 8 volunteers. In the 24 patients with AS, cartilage abnormalities were observed in 42 sacroiliac joints. More diagnoses of sacroiliitis were made using MR and CT imaging than using radiography (P < 0.001). Therefore, low-field-strength MR can be useful in detecting early sacroiliitis in patients with AS. MR imaging was able to reveal early cartilage changes and bone marrow edema, which could not be found by either CT or radiography.     

Cerebral venous sinus thrombosis associated with systemic multiple hemangiomas manifesting as chronic subdural hematoma--case report

A 35-year-old male was admitted with headache, nausea, and vomiting persisting for 2 days. Computed tomography (CT) revealed a left chronic subdural hematoma. Cerebral angiography demonstrated cerebral venous sinus thrombosis (CVST). He had presented with a subcutaneous mass involving the neck at age 2 years, which was shown to be a cavernous angioma, and thereafter shown signs of consumptive coagulopathy with systemic multiple hemangiomas. Burr hole aspiration of the hematoma was performed. Seventy-two-hours later, he developed clouding of consciousness and right hemiparesis. CT revealed a fresh hematoma in the operated subdural cavity and hemorrhagic diathesis manifested. A frontotemporoparietal large craniotomy was performed to remove the hematoma. Extensive electrocauterization was required. He had a satisfactory postoperative course. Collateral venous pathways, resulting from the CVST due to systemic multiple hemangiomas, may have caused hemodynamic stress in the bridging veins which subsequently induced chronic subdural hematoma.     

MR and cerebrospinal fluid enzymes as sensitive indicators of subclinical cerebral injury after open-heart valve replacement surgery

PURPOSE: To evaluate MR imaging and lumbar cerebrospinal fluid enzymes as potential sensitive indicators of cerebral injury after open-heart valve replacement surgery. METHODS: Thirty-four patients with cardiac valvular disease were prospectively entered into this study and then underwent valve replacement or repair under cardiopulmonary bypass using a membrane oxygenator. In 26 patients, MR head images were obtained 12 to 24 hours before surgery; repeat MR images were obtained between 1 and 2 weeks after surgery. In 18 patients, lumbar puncture cerebrospinal fluid was analyzed 24 to 48 hours after surgery; the analyses included measurement of lactic dehydrogenase, creatine phosphokinase, adenylate kinase, and neuron-specific enolase. RESULTS: After surgery, MR imaging showed new ischemic lesions in 15 (58%) of 26 patients: 7 with deep white matter hyperintense lesions; 5 with brain stem, caudate, cerebellar, or thalamic/basal ganglia infarcts; 1 with intraparenchymal hemorrhage; 1 with a subdural hematoma and cortical infarct; and 1 with a corpus callosum lesion consistent with calcium or air. These new ischemic lesions seen on MR images were associated with a focal neurologic deficit in only 4 (27%) of the 15 patients. Neuron-specific enolase and lactic dehydrogenase were abnormally elevated after surgery in 5 (28%) of 18 patients. Adenylate kinase and creatine phosphokinase (brain isozymes) were elevated in one (67%) of the patients. Two (40%) of the five patients with abnormally high neuron-specific enolase or lactic dehydrogenase after surgery also showed a new focal neurologic deficit. CONCLUSIONS: MR imaging is a sensitive measure of subclinical cerebral ischemia after cardiac valve replacement under cardiopulmonary bypass. Cerebrospinal fluid neuron-specific enolase and lactic dehydrogenase are less sensitive than MR imaging for detecting subclinical cerebral ischemia, but these values were elevated after surgery more frequently than was adenylate kinase in our patients.     

Effects of heparin-induced non-esterified free fatty acid on minimal model-derived insulin sensitivity in individuals with varying degrees of glucose intolerance

We report a case of pineocytoma associated with an unusually large cyst. A 15-year-old boy was admitted with a complaint of intermittent headache. Neurological examination was normal except for bilateral papilledema. CT scan showed triventricular hydrocephalus and a large mass. A solid portion of the tumor in the pineal and retrothalamic areas was isodense, and contained massive calcification on CT. A huge cystic portion extended far into the infratentorial, supracellebellar area. On MR, the solid tumor showed isointensity on T1-WI and iso- to high intensity on T2-WI, and was enhanced by Gd-DTPA. After a ventriculo-peritoneal shunt, the tumor was partially removed through an occipital supratentorial approach. Histological examination revealed a pineocytoma with neuronal and astrocytic differentiations. Reviewing the literature, it is most unusual to find a pineocytoma associated with a huge cyst as was seen in this case.