Enlargement of the middle meningeal artery on MR angiography in chronic subdural hematoma.

OBJECT The middle meningeal artery (MMA) is suspected to play an important role in the development of chronic subdural hematoma (CSDH). The aim of this study was to clarify whether the MMA was enlarged in patients with CSDHs. METHODS The authors retrospectively assessed 55 patients in whom CSDH was diagnosed between 2010 and 2014 and who underwent MR angiography (MRA) after the onset of CSDH. The authors compared MMA diameters between hemispheres with and without CSDHs on MR angiograms. A case-control study was also performed with 55 sex- and age-matched patients with incidental unruptured aneurysms as controls. RESULTS In 55 patients with CSDHs, the diameters of the 79 MMAs on the CSDH side were significantly larger than the diameters of the 31 MMAs on the non-CSDH side (p < 0.05). In 24 patients with bilateral CSDHs, no significant difference was found between the MMA diameters on the larger hematoma side and those on the smaller hematoma side. In 13 patients who underwent MRA before the onset of the CSDH, the MMAs on MR angiograms acquired after onset of the CSDH were significantly larger than those on MR angiograms acquired before the CSDH onset (p < 0.05). The diameters of the MMAs in 55 patients with CSDHs were significantly larger than those of the MMAs in the 55 control patients (p < 0.05). CONCLUSIONS The MMA is enlarged with development of a CSDH. Information about the MMA observed on MRA in patients with CSDHs may be useful in developing a strategy for future treatment of CSDHs.

Chronic Subdural Hematomas Associated with Arachnoid Cysts: Significance in Young Patients with Chronic Subdural Hematomas.

Although arachnoid cysts (ACs) are associated with chronic subdural hematomas (CSDHs), especially in young patients, the detailed features of CSDHs associated with ACs remain poorly understood. The objective of this study was to clarify the relationship between the location of CSDHs and ACs and the significance of ACs in young patients with CSDHs. We retrospectively assessed 605 consecutive patients 7 years of age and older who were diagnosed with a CSDH between 2002 and 2014. Twelve patients (2%) had ACs, and 10 of the 12 patients were 7-40 years of age. Patients with ACs as a complication of CSDHs were significantly younger than those without ACs (p < 0.05). Three different relationships between the location of CSDHs and ACs were found: a CSDH contacting an AC, an ipsilateral CSDH apart from an AC, and a CSDH contralateral to an AC. In 21 patients with CSDHs who were 7-40 years of age, 10 (47.6%) had ACs (AC group) and 7 (33.3%) had no associated illnesses (non-AC group). All 10 young patients with ACs showed ipsilateral CSDHs including a CSDH apart from an AC. All 17 patients in both the AC and non-AC groups showed headache but no paresis at admission. The pathogenesis of CSDHs associated with ACs may be different among the three types of locations. The clinical characteristics of patients with a combination of a CSDH and an AC including headache as a major symptom may be attributed to young age in the majority of patients with ACs.

Risks and benefits of CT angiography in spontaneous intracerebral hemorrhage.

BACKGROUND: Few studies have examined the risk of computed tomography angiography (CTA) during the acute phase of spontaneous intracerebral hemorrhage (ICH), while the benefits of CTA in ICH have been well-documented. The present study investigated both the benefits of identifying spot signs, which are supposed to indicate hematoma enlargement after admission, and risks of CTA performed during the acute phase of ICH. METHODS: We retrospectively assessed 323 consecutive patients with spontaneous ICHs admitted to our hospital between April 2009 and March 2012 and who underwent CTA on admission. RESULTS: In 80 patients (24.7 %), spot signs were demonstrated on CTA source images. Multivariate analysis revealed two independent factors correlated with presence of the spot sign: age and hematoma volume (p < 0.05 each). The presence of spot sign was associated with unfavorable outcomes at discharge and hematoma growth after admission (p < 0.05 each). Adverse events related to CTA occurred in 17 patients (5.2 %), including transient renal dysfunction in 16 patients and allergy to contrast medium in one patient. All adverse events completely resolved within 1 week. CONCLUSIONS: Presence of the spot sign indicated the possibility of hematoma growth and unfavorable outcomes. A small number of adverse events occurred in association with CTA, but without any permanent deficits. Given the potential benefits and risks, we believe that CTA performed at admission in all patients with ICH is beneficial to improve the outcomes.

The striate artery, hematoma, and spot sign on coronal images of computed tomography angiography in putaminal intracerebral hemorrhage.

BACKGROUND AND PURPOSE: A spot sign is a bright spot on computed tomography angiography source images, which is predictive of hematoma growth in spontaneous intracerebral hemorrhage, although the cause of the spot sign is unclear. Our aim was to investigate the spot sign seen on computed tomography angiography and a striate artery, which is a presumed site of intracerebral hemorrhage bleeding origin in the putamen. METHODS: In consecutive cases of spontaneous intracerebral hemorrhage in the putamen, spot signs and striate arteries were evaluated. Coronal reformat images of computed tomography angiography were created to visualize the striate arteries. Acute deterioration, defined as hematoma enlargement, emergency hematoma removal, or death within the day of admission, was reviewed. RESULTS: Of the 141 patients undergoing computed tomography angiography, 15 of the 30 patients (50%) who had spot signs showed an intrahematoma striate artery (termed spot and tail sign), which was a linear density extending from the middle cerebral artery toward the spot sign. Acute deterioration occurred more frequently in patients who had a spot and tail sign compared with patients who had spot signs without intrahematoma striate arteries (P<0.05). Multivariate analysis revealed that hematoma volume, spot signs, and intrahematoma striate arteries were independent predictors of acute deterioration (P<0.05). CONCLUSIONS: The presence of a spot and tail sign, assumed to indicate active bleeding from the striate artery, could be a more sensitive predictor of acute deterioration than the presence of a simple spot sign.

Impact of the combination of 5-aminolevulinic acid-induced fluorescence with intraoperative magnetic resonance imaging-guided surgery for glioma.

OBJECTIVE: To compare intraoperative magnetic resonance imaging (MRI)-guided resection with resection guided by 5-aminolevulinic acid (5-ALA)-induced fluorescence in patients with gliomas and to evaluate the impact of intraoperative MRI in glioma surgery. METHODS: From January 2005 to February 2009, 33 patients with gliomas (6 with World Health Organization [WHO] grade II, 7 with WHO grade III, 20 with WHO grade IV) who underwent craniotomy with neuronavigation and received 5-ALA by the same neurosurgeon were investigated retrospectively. In 19 patients, operations were performed using a combination of 5-ALA with intraoperative 1.5-T MRI. All patients were subjected to postoperative 1.5-T MRI to confirm the extent of resection. RESULTS: Of 33 patients with gliomas, 21 (4 with WHO grade III and 17 with WHO grade IV) were 5-ALA-induced fluorescence-positive (5-ALA (+)). Surgery with intraoperative MRI was performed in 10 of the 21 patients, and the average resection rate was 92.6%. The average resection rate of patients who underwent surgery without intraoperative MRI was 91.8%. 5-ALA-induced fluorescence was not detected in 12 patients (6 with WHO grade II, 3 with WHO grade III, and 3 with WHO grade IV) with gliomas. Surgery with intraoperative MRI was performed in 9 of 12 patients, and the average resection rate was 89.2%. The average resection rate of patients who underwent surgery without intraoperative MRI was 68.7%. Intraoperative MRI-guided tumor resection resulted in a better resection rate in patients with 5-ALA-induced fluorescence-negative (5-ALA (-)) gliomas than in patients with 5-ALA (+) gliomas (20.5% vs 0.8%). CONCLUSIONS: Intraoperative MRI-guided resection is a powerful tool to treat 5-ALA (-) gliomas (mostly low grade), and 5-ALA is useful for high-grade gliomas. The combination of intraoperative MRI and 5-ALA has a synergistic effect in glioma surgery. Additionally, precise tumor grading in preoperative imaging studies can be difficult. Surgery for gliomas should be performed using both 5-ALA-induced fluorescence and intraoperative MRI-guided resection.

Mechanism of injury to the corpus callosum, with particular reference to the anatomical relationship between site of injury and adjacent brain structures.

The location of corpus callosum injury was investigated using magnetic resonance imaging in 92 patients. The anatomical relationships in the region around the corpus callosum were also evaluated to clarify involvement in the mechanism of corpus callosum injury in 20 normal volunteers. Lesions in the posterior half of the corpus callosum accounted for 80% of corpus callosum injuries. The falx was increasingly elongated toward the posterior portion of the corpus callosum and the corpus callosum was thinnest at the body-splenium junction in the normal volunteers. The mechanism of corpus callosum injury apparently involves the following factors. The posterior half of the falx is closer to the corpus callosum than the anterior half. Therefore, the anterior part of the corpus callosum easily moves with lateral movement of the cerebral hemispheres, and the strain is likely to be concentrated in the posterior half of the corpus callosum, because the falx greatly limits lateral movement of the hemisphere in the posterior region. The corpus callosum is easily distorted at the thinnest part of the body-splenium junction. Therefore, corpus callosum injury predominantly occurs in the posterior half of the corpus callosum.

Fully functional MR-compatible flexible operating table resolves the neurosurgeon's dilemma over use of intraoperative MRI.

In February 2006, our hospital officially opened the Magnetic Resonance / X-ray / operation (MRXO) suite, which is the first hybrid neurosurgical procedure suite to combine magnetic resonance imaging (MRI), computed tomography and angiography with a neurosurgical operating room. For this suite, we have developed a specially designed fully functional magnetic resonance (MR)-compatible flexible operating table. Here, we describe the details of this operating table and discuss its advantages. Its MR-compatible tabletop can be bent during surgery. The specially designed MR-compatible flexible operating table for the MRXO suite reduces limitations on neurosurgeons during standard neurosurgical procedures. Also, it does not give rise to imaging artifacts on MRI. The specially designed MR-compatible flexible operating table resolves the neurosurgeon's dilemma over use of intraoperative MRI.

World's first magnetic resonance imaging/x-ray/operating room suite: a significant milestone in the improvement of neurosurgical diagnosis and treatment.

OBJECT: In February 2006, the magnetic resonance/x-ray/operating room (MRXO) suite opened at the authors' institution. This is the first hybrid neurosurgical procedure suite to combine magnetic resonance (MR) imaging, computed tomography (CT), and angiography within a neurosurgical operating room (OR). In the present paper the authors describe the concept of the MRXO as well as their first 10 months of experience using this suite, and discuss its advantages and limitations. METHODS: In the MRXO suite, the combined OR and angiography (OR-angiography) station is located in the middle of the suite, and the MR imaging and CT scanning stations are each installed in an adjoining bay connected to the OR-angiography station by shielded sliding doors. The surgical, MR imaging, angiography, and CT tables are positioned in order of use. The patient lies on a fully MR imaging- and radiography-compatible mobile patient tabletop that is used to move the patient quickly and safely among the tables in the imaging and operating components of the MRXO suite. RESULTS: The authors performed all interventional procedures safely. The specially designed operating tabletop of the MRXO suite reduced the limitations on neurosurgeons during standard neurosurgical procedures. This hybrid suite helps to provide high-quality intraoperative imaging, greatly reducing the risk of unexpected events during the procedure. CONCLUSIONS: The MRXO suite, which combines OR and imaging equipment, represents a significant milestone in the improvement of neurosurgical diagnosis and treatment and other interventional procedures. Another advantage of the MRXO suite is its cost-effectiveness, which is partly due to its streamlined imaging procedure.

[The usefulness of MRI around the tentorial incisura for determining the mechanism of brain stem injury: a case report].

We report a case of isolated brain stem injury caused by the tentorium cerebelli. A 17-year-old male was admitted to our hospital. Thirty minutes before admission, he was struck by another motorcycle while driving his own motorcycle. The Glasgow Coma Scale (GCS) was 10. He had no extremity weakness and his pupils were normal. CT scan showed no evidence of intracranial lesions except for facial bone fractures. His consciousness level improved to GCS 13 at 6 hours after admission. Follow-up CT scan was normal, however MRI 3 days after admission showed a contusion at the left lateral midbrain. He was discharged without any neurological deficits on 6 days after admission. Analysis of the distance between the brain stem and the tentorial margin using MR cisternography showed that the left side was shorter than the right side. We presumed that an isolated lateral brain stem injury was caused by the direct impact of the tentorium cerebelli. Typically the location of this type of lesion is present in the same side as that of impact. However in this case the orientation was opposite to that. We considered that the distance between the brain stem and the tentorial margin affected the mechanism of this lesion.