Mikito Uchida

Diffusion tensor tractography predicts motor functional outcome in patients with spontaneous intracerebral hemorrhage.

OBJECTIVEWe prospectively investigated the predictive value of diffusion tensor tractography for motor functional outcome in a case series of patients with intracerebral hemorrhage. METHODSDiffusion tensor tractography was performed in 17 patients with intracerebral hemorrhage (putamen, nine patients; thalamus, seven patients; combined, one patient) within 5 days after onset. Mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values along the corticospinal tracts at the level of the hematoma were measured bilaterally, and the ratios of values (hematoma side/contralateral side) were determined as FA and ADC ratios, respectively. Patients were evaluated for motor function on admission and at 3 months after onset using the manual muscle test score and then divided into good (manual muscle test, 4–5) and poor (manual muscle test, 0–3) motor function groups. RESULTSFA ratio measured shortly after the onset of intracerebral hemorrhage correlated well with motor functional outcome at 3 months (P < 0.05) but not with motor function on admission. FA ratios in the group with good motor functional outcome were significantly higher than those in the group with poor motor functional outcome (P < 0.01). The ADC ratio did not correlate with motor function either on admission or at 3 months. All patients with an FA ratio greater than 0.8 had a good motor functional outcome. In three patients, however, motor functional outcomes were favorable even though FA ratios were not high; in these patients, ADC ratios tended to be elevated. CONCLUSIONMotor functional outcome in patients with intracerebral hemorrhage can be predicted by measuring FA values using diffusion tensor tractography.

Effect of intracranial pressure on the diameter of the optic nerve sheath

OBJECT The subarachnoid space around the optic nerve in the orbit can be visualized using T2-weighted MR imaging with the fat-saturation pulse sequence. The optic nerve sheath (ONS) diameter can be estimated by measuring the outer diameter of the subarachnoid space. Dilated ONS is associated with idiopathic intracranial hypertension and hydrocephalus, and is believed to reflect increased intracranial pressure (ICP). The relationship between dilated ONS and ICP is unclear because of the difficulty in obtaining noninvasive measurements of ICP. The authors investigated the relationship between subdural pressure measured at the time of surgery and ONS diameter measured on MR images in patients with chronic subdural fluid collection. METHODS Twelve patients underwent bur-hole craniostomy with continuous drainage for chronic subdural hematoma or hygroma in 2006. Orbital thin-slice fat-saturated MR images were obtained before and after surgery, and the ONS diameters were measured just behind the optic globe. Subdural pressure was measured using a manometer before opening of the dura mater. RESULTS A significant correlation was found between the ONS diameter and the subdural pressure (correlation coefficient 0.879, p = 0.0036). The ONS diameter before surgery (6.1 +/- 0.7 mm) was significantly reduced after surgery (4.8 +/- 0.9 mm, p = 0.003; measurements are expressed as the mean +/- standard deviation). CONCLUSIONS Increased ONS diameter measured on coronal orbital thin-slice fat-saturated T2-weighted MR images is a strong indicator of increased ICP, and helps to differentiate between passive subdural fluid collection due to brain atrophy and subdural hygroma with increased ICP.

Diagnostic Value of Spinal MR Imaging in Spontaneous Intracranial Hypotension Syndrome

BACKGROUND AND PURPOSE: Spontaneous intracranial hypotension (SIH) presents with orthostatic headache, and the diagnosis is made on the basis of low CSF pressure and brain MR imaging findings characteristic of the disorder. However, a broad spectrum of symptoms and MR imaging findings of SIH is recognized, and some cases have no typical MR imaging abnormalities. SIH is believed to be caused by CSF leakage from the spinal dural sac, whereas the usefulness of MR imaging of the spine remains unclear. Our aim was to elucidate the diagnostic value of brain and spinal MR imaging MATERIALS AND METHODS: The sensitivities for the detection of SIH were retrospectively evaluated in 18 patients with SIH treated in our institutions between January 1998 and August 2007. RESULTS: Brain MR imaging detected abnormalities in 15 of the 18 patients (83%): diffuse pachymeningeal enhancement in 15 (83%), descent of the cerebellar tonsil in 13 (72%), brain stem sagging in 13 (72%), enlargement of the pituitary gland in 12 (67%), and subdural fluid collection in 13 (72%). Spinal MR imaging detected abnormalities in 17 of the 18 patients (94%): distention of the epidural veins in 14 (78%), epidural fluid collection on fat-saturated T2-weighted images in 16 (89%), and abnormal visualization of the nerve root sleeve in only 1 (6%). The sensitivity for SIH was 83% for brain MR imaging and 94% for spinal MR imaging. CONCLUSIONS: Spinal MR imaging is useful for the diagnosis of SIH, especially in the early stage.

Effects of cilostazol on cerebral vasospasm after aneurysmal subarachnoid hemorrhage: a multicenter prospective, randomized, open-label blinded end point trial

OBJECT Cerebral vasospasm following aneurysmal subarachnoid hemorrhage (SAH) is a major cause of subsequent morbidity and mortality. Cilostazol, a selective inhibitor of phosphodiesterase 3, may attenuate cerebral vasospasm because of its antiplatelet and vasodilatory effects. A multicenter prospective randomized trial was conducted to investigate the effect of cilostazol on cerebral vasospasm. METHODS Patients admitted with SAH caused by a ruptured anterior circulation aneurysm who were in Hunt and Kosnik Grades I to IV and were treated by clipping within 72 hours of SAH onset were enrolled at 7 neurosurgical sites in Japan. These patients were assigned to one of 2 groups: the usual therapy group (control group) or the add-on 100 mg cilostazol twice daily group (cilostazol group). The group assignments were done by a computer-generated randomization sequence. The primary study end point was the onset of symptomatic vasospasm. Secondary end points were the onset of angiographic vasospasm and new cerebral infarctions related to cerebral vasospasm, clinical outcome as assessed by the modified Rankin scale, and length of hospitalization. All end points were assessed for the intention-to-treat population. RESULTS Between November 2009 and December 2010, 114 patients with SAH were treated by clipping within 72 hours from the onset of SAH and were screened. Five patients were excluded because no consent was given. Thus, 109 patients were randomly assigned to the cilostazol group (n = 54) or the control group (n = 55). Symptomatic vasospasm occurred in 13% (n = 7) of the cilostazol group and in 40% (n = 22) of the control group (p = 0.0021, Fisher exact test). The incidence of angiographic vasospasm was significantly lower in the cilostazol group than in the control group (50% vs 77%; p = 0.0055, Fisher exact test). Multiple logistic analyses demonstrated that nonuse of cilostazol is an independent factor for symptomatic and angiographic vasospasm. The incidence of new cerebral infarctions was also significantly lower in the cilostazol group than in the control group (11% vs 29%; p = 0.0304, Fisher exact test). Clinical outcomes at 1, 3, and 6 months after SAH in the cilostazol group were better than those in the control group, although a significant difference was not shown. There was also no significant difference in the length of hospitalization between the groups. No severe adverse event occurred during the study period. CONCLUSIONS Oral administration of cilostazol is effective in preventing cerebral vasospasm with a low risk of severe adverse events. Clinical trial registration no. UMIN000004347, University Hospital Medical Information Network Clinical Trials Registry.

Decreased Diameter of the Optic Nerve Sheath Associated with CSF Hypovolemia

SUMMARY: The subarachnoid space around the optic nerve can be detected by fat-saturated T2-weighted MR imaging of the orbit, and dilation of this space reflects increased intracranial pressure. We examined 3 patients with CSF hypovolemia with MR imaging of the orbit and measured the optic nerve sheath diameter before and after treatment. We showed that the subarachnoid space is decreased in patients with CSF hypovolemia and the usefulness of this finding.

Effectiveness of an epidural blood patch for patients with intracranial hypotension syndrome and persistent spinal epidural fluid collection after treatment

OBJECT Magnetic resonance imaging may show a fluid collection in the spinal epidural space of patients with spontaneous intracranial hypotension syndrome (SIHS), but the chronological changes remain unclear. METHODS Brain and spine MR imaging findings were analyzed in 16 patients (9 women and 7 men, mean age 48.6 years) with SIHS before and after treatment. RESULTS Diffuse dural enhancement was seen in 15 patients, and the epidural fluid collection in the spinal canal was clear in 15 and equivocal in 1. Symptoms disappeared after bed rest in 1 patient, and an epidural blood patch was performed in 15 patients, resulting in complete resolution of symptoms in 13. After the follow-up period (range 1-20 months, mean 5.0 months), 1 patient had persistent mild headache that gradually worsened in the afternoon, and another patient complained of heaviness of the eyes. Follow-up MR imaging demonstrated disappearance of the dural enhancement in all patients, but a fluid collection in the spinal canal remained in 4. Two of the 4 patients had persistent symptoms, but the other patients exhibited complete resolution of the symptoms. CONCLUSIONS An epidural blood patch is effective for sealing of CSF leaks, but the resolution of SIHS-related symptoms does not always imply complete eradication of the leakage.

Evaluation of Cervical Myelopathy Using Apparent Diffusion Coefficient Measured by Diffusion-Weighted Imaging

BACKGROUND AND PURPOSE: Intramedullary high signal intensity on T2-weighted imaging was frequently observed in patients with CSM, although this finding does not well correlate with severity or prognosis of CSM. Instead of this nonquantitative information, another measure for CSM is desired. The work was focused primarily on assessing the relationships between ADC values and clinical and radiologic severity for the diagnosis of CSM. MATERIALS AND METHODS: The relationship between ADC values measured in the spinal cord at 322 intervertebral levels of 66 patients and clinical factors were analyzed. RESULTS: ADC values in the spinal cord significantly increased with the degree of spinal cord compression and decreased with time after decompression surgery. Patients with higher ADC values had lower preoperative JOA scores and tended to show poorer clinical recovery. CONCLUSIONS: ADC values appear to indicate the severity of spinal cord compression and clinical recovery after decompression surgery, so spondylotic myelopathy may partly be predicted preoperatively by using ADC values.

Internal Carotid Artery Occlusion Manifesting Only as Oculomotor Nerve Palsy

Oculomotor nerve palsy is very rare as the only manifestation of internal carotid artery (ICA) occlusion, and the angiographic findings have not been described in detail. We present a case of ipsilateral ICA occlusion manifesting as only sudden onset of oculomotor nerve palsy. Cerebral angiography showed occlusion of the ICA from the cervical portion to the ophthalmic portion. Distal blood flow was compensated through an anastomosis from other arteries. Ischemia of the oculomotor nerve was thought to be caused by loss of supply from branches arising from the occluded cavernous portion of the ICA.

Jugular Compression and Radionuclide Cisternographic Patterns in Patients With Chronic Headache

Objective.—We investigated the value of the jugular compression test (JCT) in screening patients with chronic headache attributable to persistent cerebrospinal fluid (CSF) leakage.

Unsuccessful tracer injection in radionuclide cisternography revisited

Since cerebrospinal fluid (CSF) leakage is highlighted as a cause of persistent headache, radionuclide cisternography has been increasingly performed in Japan to confirm the disorder, although the limited ability of the examination should be recognized. We present 3 cases in which failure of a tracer injection was strongly suspected. In 2 cases with chronic symptoms, the tracer appeared to be injected into the epidural space, because of irregular initial accumulation of the tracer and lack of diffusion along the CSF cavity. Another is a case with spontaneous CSF leakage confirmed by MRI, and the tracer was thought to be injected into the leaked fluid accumulated in the spinal epidural space. Tracer in the CSF space rapidly disappeared within several hours in all cases. As such cisternographic images may be misdiagnosed as severe CSF leakage, careful interpretation of images in patients especially with no typical MR findings of CSF leakage is necessary. Excessive tracer clearance from the body suggests such technical failure.