Apparent brain temperature imaging with multi-voxel proton magnetic resonance spectroscopy compared with cerebral blood flow and metabolism imaging on positron emission tomography in patients with unilateral chronic major cerebral artery steno-occlusive disease.

PURPOSE: The purpose of the present study was to determine whether apparent brain temperature imaging using multi-voxel proton magnetic resonance (MR) spectroscopy correlates with cerebral blood flow (CBF) and metabolism imaging in the deep white matter of patients with unilateral chronic major cerebral artery steno-occlusive disease. METHODS: Apparent brain temperature and CBF and metabolism imaging were measured using proton MR spectroscopy and 15O-positron emission tomography (PET), respectively, in 35 patients. A set of regions of interest (ROIs) of 5 × 5 voxels was placed on an MR image so that the voxel row at each edge was located in the deep white matter of the centrum semiovale in each cerebral hemisphere. PET images were co-registered with MR images with these ROIs and were re-sliced automatically using image analysis software. RESULTS: In 175 voxel pairs located in the deep white matter, the brain temperature difference (affected hemisphere - contralateral hemisphere: ΔBT) was correlated with cerebral blood volume (CBV) (r = 0.570) and oxygen extraction fraction (OEF) ratios (affected hemisphere/contralateral hemisphere) (r = 0.641). We excluded voxels that contained ischemic lesions or cerebrospinal fluid and calculated the mean values of voxel pairs in each patient. The mean ΔBT was correlated with the mean CBF (r = - 0.376), mean CBV (r = 0.702), and mean OEF ratio (r = 0.774). CONCLUSIONS: Apparent brain temperature imaging using multi-voxel proton MR spectroscopy was correlated with CBF and metabolism imaging in the deep white matter of patients with unilateral major cerebral artery steno-occlusive disease.

Relation between brain temperature and white matter damage in subacute carbon monoxide poisoning.

In the previous studies, carbon monoxide (CO) poisoning showed an imbalance between cerebral perfusion and metabolism in the acute phase and the brain temperature (BT) in these patients remained abnormally high from the acute to the subacute phase. As observed in chronic ischemic patients, BT can continuously remain high depending on impairments of cerebral blood flow and metabolism; this is because heat removal and production system in the brain may mainly be maintained by the balance of these two factors; thus, cerebral white matter damage (WMD) affecting normal metabolism may affect the BT in patients with CO poisoning. Here, we investigated whether the BT correlates with the degree of WMD in patients with subacute CO-poisoning. In 16 patients with subacute CO-poisoning, the BT and degree of WMD were quantitatively measured by using magnetic resonance spectroscopy and the fractional anisotropy (FA) value from diffusion tensor imaging dataset. Consequently, the BT significantly correlated with the degree of WMD. In particular, BT observed in patients with delayed neuropsychiatric sequelae, a crucial symptom with sudden-onset in the chronic phase after CO exposure, might indicate cerebral hypo-metabolism and abnormal hemodynamics like "matched perfusion," in which the reduced perfusion matches the reduced metabolism.

Brain temperature measured by 1H-magnetic resonance spectroscopy in acute and subacute carbon monoxide poisoning.

INTRODUCTION: Brain temperature (BT) is associated with the balance between cerebral blood flow and metabolism according to the "heat-removal" theory. The present study investigated whether BT is abnormally altered in acute and subacute CO-poisoned patients by using (1)H-magnetic resonance spectroscopy (MRS). METHODS: Eight adult CO-poisoned patients underwent 3-T magnetic resonance imaging in the acute and subacute phases after CO exposure. MRS was performed on deep cerebral white matter in the centrum semiovale, and MRS-based BT was estimated by the chemical shift difference between water and the N-acetyl aspartate signal. We defined the mean BT + 1.96 standard deviations of the BT in 15 healthy controls as the cutoff value for abnormal BT increases (p < 0.05) in CO-poisoned patients. RESULTS: BT of CO-poisoned patients in both the acute and subacute phases was significantly higher than that of the healthy control group. However, BT in the subacute phase was significantly lower than in the acute phase. On the other hand, no significant difference in body temperature was observed between acute and subacute CO-poisoned patients. BT weakly correlated with body temperature, but this correlation was not statistically significant (rho = 0.304, p = 0.2909). CONCLUSIONS: The present results suggest that BT in CO-poisoned patients is abnormally high in the acute phase and remains abnormal in the subacute phase. BT alteration in these patients may be associated with brain perfusion and metabolism rather than other factors such as systemic inflammation and body temperature.

Postoperative increase in cerebral white matter fractional anisotropy on diffusion tensor magnetic resonance imaging is associated with cognitive improvement after uncomplicated carotid endarterectomy: tract-based spatial statistics analysis.

BACKGROUND: Carotid endarterectomy (CEA) might improve cognitive function. Fractional anisotropy (FA) values in the cerebral white matter derived from diffusion tensor magnetic resonance imaging (DTI) correlate with cognitive function in patients with various central nervous system diseases. OBJECTIVE: To use tract-based spatial statistics to determine whether postoperative changes of FA values in the cerebral white matter derived from DTI are associated with cognitive improvement after uncomplicated CEA. METHODS: In 80 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), FA values in the cerebral white matter were derived from DTI before and 1 month after surgery and were analyzed by using tract-based spatial statistics. Neuropsychological testing, consisting of the Wechsler Adult Intelligence Scale Revised, the Wechsler Memory Scale and the Rey-Osterreith Complex Figure test, was also performed preoperatively and after the first postoperative month. RESULTS: Based on the neuropsychological assessments, 11 (14%) patients were defined as having postoperatively improved cognition. The difference between the 2 mean FA values (postoperative values minus preoperative values) in the cerebral hemisphere ipsilateral to surgery was significantly associated with postoperative cognitive improvement (95% confidence intervals, 2.632-9.877; P = .008). White matter FA values in patients with postoperative cognitive improvement were significantly increased after surgery in the whole ipsilateral cerebral hemisphere, in the contralateral anterior cerebral artery territory, and in the watershed zone between the contralateral anterior and middle cerebral arteries. CONCLUSION: Postoperative increase in cerebral white matter FA on DTI is associated with cognitive improvement after uncomplicated CEA.

Postoperative cerebral white matter damage associated with cerebral hyperperfusion and cognitive impairment after carotid endarterectomy: a diffusion tensor magnetic resonance imaging study.

BACKGROUND: Cerebral hyperperfusion after carotid endarterectomy (CEA), even when asymptomatic, often impairs cognitive function. However, conventional magnetic resonance (MR) imaging rarely demonstrates structural brain damage associated with postoperative cognitive impairment. MR diffusion tensor imaging (DTI) is potentially more sensitive for detection of white matter damage. Among the common parameters derived by DTI, fractional anisotropy (FA) is a marker of tract integrity, and mechanical disruption of axonal cylinders and loss of continuity of myelin sheaths may be responsible for reduced FA in white matter. The purpose of the present study was to determine whether postoperative cerebral white matter damage that can be detected by FA derived by DTI is associated with cerebral hyperperfusion after CEA and correlates with postoperative cognitive impairment. METHODS: In 70 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), cerebral blood flow (CBF) was measured using single-photon emission computed tomography (SPECT) before and immediately after CEA and on postoperative day 3. FA values in cerebral white matter were assessed using DTI before and 1 month after surgery. These values were normalized and analyzed using statistical parametric mapping 5. In each corresponding voxel in the pre- and postoperative normalized FA maps of each patient, a postoperative FA value minus a preoperative FA value was calculated, and a voxel with postoperatively reduced FA was defined based on data obtained from healthy volunteers. The number of voxels with postoperatively reduced FA was calculated and defined as the volume with postoperatively reduced FA. Neuropsychological testing, consisting of the Wechsler Adult Intelligence Scale Revised, the Wechsler Memory Scale and the Rey-Osterreith Complex Figure test, was also performed preoperatively and after the first postoperative month. Postoperative cognitive impairment on neuropsychological testing in each patient was defined based on data obtained from patients with asymptomatic unruptured cerebral aneurysms. RESULTS: Post-CEA hyperperfusion on brain perfusion SPECT (CBF increase ≥100% compared with preoperative values) and postoperative cognitive impairment on neuropsychological testing were observed in 11 (16%) and 9 patients (13%), respectively. The volume with postoperatively reduced FA in cerebral white matter ipsilateral to surgery was significantly greater in patients with post-CEA hyperperfusion than in those without (p < 0.0001). This volume in cerebral white matter ipsilateral to surgery was also significantly associated with postoperative cognitive impairment (95% confidence interval, 1.559-8.853; p = 0.0085). CONCLUSIONS: Cerebral hyperperfusion after CEA results in postoperative cerebral white matter damage that correlates with postoperative cognitive impairment.

Prediction of motor function outcome after intracerebral hemorrhage using fractional anisotropy calculated from diffusion tensor imaging.

BACKGROUND: The efficacy of surgical evacuation in patients with intracerebral hemorrhage (ICH) remains unclear for recovery of motor function. The relationship between improvement of motor function outcome and sequential change of fractional anisotropy (FA) values was investigated in patients with ICH, to explore whether motor function outcome can be predicted in the early phase. Indication of the surgical hematoma evacuation was also considered. METHODS: This prospective study included 23 patients with ICH. All patients underwent diffusion tensor imaging to measure the FA value five times: within 3 days, day 14, day 30, day 60, and day 90 after the onset. The regions of interest were determined on the b = 0 step of the echo planar imaging scans in the bilateral cerebral peduncles and were automatically transferred onto the FA images. The FA value was then calculated for each patient. Patients were divided into good and poor recovery groups according to the motor function outcome on day 90. RESULTS: The mean FA value of the poor recovery group gradually decreased until day 90, but remained unchanged in the good recovery group. The mean FA value on day 3 was significantly higher (p < 0.001) in the good recovery group (0.745 ± 0.0073) than in the poor recovery group (0.682 ± 0.0090). Receiver operating characteristic curve analysis showed that the FA value on day 3 could predict motor function outcome with a sensitivity of 100% and a specificity of 77.8% at an FA value of 0.7 on day 3. CONCLUSION: The main finding of this study was that the FA values of the cerebral peduncle on the pathological side in patients with ICH on day 3 could predict the motor function outcome on day 90.

Fractional anisotropy in the centrum semiovale as a quantitative indicator of cerebral white matter damage in the subacute phase in patients with carbon monoxide poisoning: correlation with the concentration of myelin basic protein in cerebrospinal fluid.

Carbon monoxide (CO) poisoning leads to demyelination of cerebral white matter (CWM) fibers, causing chronic neuropsychiatric symptoms. To clarify whether fractional anisotropy (FA) from diffusion tensor imaging in the centrum semiovale can depict demyelination in the CWM during the subacute phase after CO inhalation, we examined correlations between FA in the centrum semiovale and myelin basic protein (MBP) in cerebrospinal fluid. Subjects comprised 26 adult CO-poisoned patients ≤60 years old. MBP concentration was examined for all patients at 2 weeks after CO inhalation. The mean FA of the centrum semiovale bilaterally at 2 weeks was also examined for all patients and 21 age-matched healthy volunteers as controls. After these examinations, the presence of chronic symptoms was checked at 6 weeks after CO poisoning. Seven patients displayed chronic symptoms, of whom six showed abnormal MBP concentrations. The remaining 19 patients presented no chronic symptoms and no abnormal MBP concentrations, with MBP concentrations undetectable in 16 patients. The MBP concentration differed significantly between patients with and without chronic symptoms. The mean FA was significantly lower in patients displaying chronic symptoms than in either patients without chronic symptoms or controls. After excluding the 16 patients with undetectable MBP concentrations, a significant correlation was identified between MBP concentration and FA in ten patients. The present results suggest that FA in the centrum semiovale offers a quantitative indicator of the extent of demyelination in damaged CWM during the subacute phase in CO-poisoned patients.

Detecting damaged regions of cerebral white matter in the subacute phase after carbon monoxide poisoning using voxel-based analysis with diffusion tensor imaging.

INTRODUCTION: The present study aimed to detect the main regions of cerebral white matter (CWM) showing damage in the subacute phase for CO-poisoned patients with chronic neurological symptoms using voxel-based analysis (VBA) with diffusion tensor imaging (DTI). METHODS: Subjects comprised 22 adult CO-poisoned patients and 16 age-matched healthy volunteers as controls. Patients were classified into patients with transient acute symptoms only (group A) and patients with chronic neurological symptoms (group S). In all patients, DTI covering the whole brain was performed with a 3.0-T magnetic resonance imaging system at 2 weeks after CO exposure. As procedures for VBA, all fractional anisotropy (FA) maps obtained from DTI were spatially normalized, and FA values for all voxels in the whole CWM on normalized FA maps were statistically compared among the two patient groups and controls. RESULTS: Voxels with significant differences in FA were detected at various regions in comparisons between groups S and A and between group S and controls. In these comparisons, more voxels were detected in deep CWM, including the centrum semiovale, than in other regions. A few voxels were detected between group A and controls. Absolute FA values in the centrum semiovale were significantly lower in group S than in group A or controls. CONCLUSIONS: VBA demonstrated that CO-poisoned patients with chronic neurological symptoms had already suffered damage to various CWM regions in the subacute phase. In these regions, the centrum semiovale was suggested to be the main region damaged in the subacute phase after CO inhalation.

1H-magnetic resonance spectroscopy indicates damage to cerebral white matter in the subacute phase after CO poisoning.

OBJECTIVE: The authors examined whether (1)H-magnetic resonance spectroscopy (MRS) can identify damage to the centrum semiovale in the subacute phase after CO exposure. METHODS: Subjects comprised 29 adult patients who were treated with hyperbaric oxygenation within a range of 4-95 h (mean 18.7 h) after CO exposure. Subjects were classified into three groups according to clinical behaviours: Group A, patients with transit acute symptoms only; Group P, patients with persistent neurological symptoms; and Group D, patients with 'delayed neuropsychiatric sequelae' occurring after a lucid interval. MRS of bilateral centrum semiovale was performed 2 weeks after CO inhalation for all patients and 13 healthy volunteers. The mean ratios of choline-containing compounds/creatine ((mean)Cho/Cr) and N-acetylaspartate/Cr ((mean)NAA/Cr) for bilateral centrum semiovale were calculated and compared between the three CO groups and controls. Myelin basic protein (MBP) concentration in cerebrospinal fluid was examined at 2 weeks to evaluate the degree of demyelination in patients. RESULTS: MBP concentration was abnormal for almost all patients in Groups P and D, but was not abnormal for any Group A patients. The (mean)Cho/Cr ratios were significantly higher in Groups P and D than in Group A. No significant difference in (mean)NAA/Cr ratio was seen between the three pathological groups and controls. A significant correlation was identified between MBP and (mean)Cho/Cr ratio. CONCLUSIONS: These results suggest that the Cho/Cr ratio in the subacute phase after CO intoxication represents early demyelination in the centrum semiovale, and can predict chronic neurological symptoms.

Brain temperature measured by using proton MR spectroscopy predicts cerebral hyperperfusion after carotid endarterectomy.

PURPOSE: To determine whether brain temperature measured by using preoperative proton magnetic resonance (MR) spectroscopy could help identify patients at risk for cerebral hyperperfusion after carotid endarterectomy (CEA). MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Acquisition of proton MR spectroscopic data by using point-resolved spectroscopy without water suppression was performed before CEA in the bilateral cerebral hemispheres of 84 patients with unilateral internal carotid artery stenosis (> or =70%) and without contralateral internal carotid artery steno-occlusive disease. Brain temperature was calculated from the chemical shift difference between water and N-acetylaspartate signals at proton MR spectroscopy. Cerebral blood flow (CBF) was also measured by using single photon emission computed tomography and N-isopropyl-p-[(123)I]-iodoamphetamine before and immediately after CEA and on the 3rd postoperative day. The relationship between each variable and the development of post-CEA hyperperfusion (CBF increase > or = 100% compared with preoperative values) was evaluated with univariate statistical analysis followed by multivariate analysis. RESULTS: A linear correlation was observed between preoperative brain temperature difference (the value in the affected hemisphere minus the value in the contralateral hemisphere) and increases in CBF immediately after CEA (r = 0.763 and P < .001) when the preoperative brain temperature difference was greater than 0. Cerebral hyperperfusion immediately after CEA was observed in nine patients (11%). Elevated preoperative brain temperature difference was the only significant independent predictor of post-CEA hyperperfusion. When elevated brain temperature difference was defined as a marker of hemodynamic impairment in the affected cerebral hemisphere, use of preoperative brain temperature difference resulted in 100% sensitivity and 87% specificity, with a 47% positive predictive value and a 100% negative predictive value for the prediction of post-CEA hyperperfusion. Hyperperfusion syndrome developed on the 3rd and 4th postoperative days in two of the nine patients who exhibited hyperperfusion immediately after CEA. CONCLUSION: Brain temperature measured by using preoperative proton MR spectroscopy may help identify patients at risk for post-CEA cerebral hyperperfusion.

Assessment of damage to cerebral white matter fiber in the subacute phase after carbon monoxide poisoning using fractional anisotropy in diffusion tensor imaging.

INTRODUCTION: Chronic neuropsychiatric symptoms after carbon monoxide (CO) poisoning are caused by demyelination of cerebral white matter fibers. We examined whether diffusion tensor imaging can sensitively represent damage to fibers of the centrum semiovale in the subacute phase after CO intoxication. METHODS: Subjects comprised 13 adult patients with CO poisoning, classified into three groups according to clinical behaviors: group A, patients with transit acute symptoms only; group P, patients with persistent neurological symptoms; and group D, patients with "delayed neuropsychiatric sequelae" occurring after a lucid interval. Median fractional anisotropy (FA) and apparent diffusion coefficient (ADC) of the centrum semiovale bilaterally at 2 weeks were compared between these groups and a control group of ten healthy volunteers. Myelin basic protein (MBP) concentration in cerebrospinal fluid was examined at 2 weeks to evaluate the degree of demyelination in patients. RESULTS: MBP concentration was abnormal or detectable for all group P and group D patients but was undetectable for all patients assigned to group A. Low FA values in groups P and D displaying chronic neurological symptoms clearly differed from those in controls and group A without chronic neurological symptoms, but ADC showed no significant differences between patient groups. CONCLUSIONS: MBP concentration at 2 weeks after CO inhalation confirmed a certain extent of demyelination in the central nervous system of patients who would develop chronic neurological symptoms. In these patients, FA sensitively represented damage to white matter fibers in the centrum semiovale in the subacute phase after CO intoxication.

Choice of posterior subtemporal transtentorial approach for tumor resection in deep anteromedial superior cerebellum.

The anteromedial superior cerebellar tumor can be accessed by various routes. For tumor presenting at the cerebellar surface in this region, the optimal approach remains contentious. Furthermore, which of the various routes offers the optimal approach to a tumor that is not present at the cerebellar surface but lies deep anteromedial superior cerebellum is a matter of debate. We report herein the case of a 44-year-old woman with hemangioblastoma deep within the subcortex of the anteromedial superior cerebellum. Preoperative magnetic resonance (MR) imaging and three-dimensional anisotropy contrast MR axonography using diffusion-weighted MR imaging demonstrated that the posterior subtemporal transtentorial (PSTT) approach would provide a shorter surgical corridor, minimal cerebellar split, and better preservation of nerve fibers, compared to the other approaches. Surgical tumor removal was successfully achieved using the PSTT approach. During surgery, the PSTT approach provided an operative field that enabled visualization of the proximal side of the superior cerebellar artery as the tumor feeding vessel. Although the vein of Labbé inserted just into the transverse-sigmoid junction, injury to this vein was avoided using optimal head position, cerebrospinal fluid drainage, and various devices. For patients with tumor located within the subcortex of the anteromedial superior cerebellum, the PSTT approach is recommended as an optimal surgical route. Scrupulous evaluation using preoperative neuroimaging is crucial when deciding on the surgical approach.

Subtemporal approach to basilar tip aneurysm with division of posterior communicating artery: technical note.

The subtemporal approach with division of the posterior communicating artery (PcomA) is described for treating aneurysms of the basilar tip. When the ipsilateral posterior cerebral artery (PCA) interferes with visibility and manipulation around the aneurysm neck and the artery is tethered by the PcomA and not mobilized, the PcomA can be divided near the junction with the PCA. The procedure permits PCA mobilization and exposes the neck of the aneurysm. We applied this procedure to a patient with a ruptured aneurysm of the basilar tip. The postoperative course was uneventful except for transient left oculomotor nerve palsy. Postoperative cerebral angiography and magnetic resonance imaging confirmed the respective disappearance of the aneurysm and no new ischemic lesions. The subtemporal approach allows safer and easier division of the PcomA near the junction to the PCA compared with the pterional approach, and the present procedure is more suitable for the subtemporal approach.

Computer-assisted identification of the central sulcus in patients with brain tumors using MRI.

PURPOSE: To develop computer-assisted image processing to identify the central sulcus from the MRI data sets in patients with brain tumors. MATERIALS AND METHODS: All MR images were acquired with a 3.0 Tesla scanner by three-dimensional (3D) spoiled gradient recalled acquisition using the steady state (SPGR) gradient-echo sequence and short inversion time inversion-recovery fast spin-echo sequence. The sulci were extracted automatically from reconstructed two-dimensional images of the cortical surface of 30 patients with brain tumors, and the extracted sulci were scored according to matching of the accepted anatomical features of the central sulcus. The candidates with the three highest scores were then superimposed on the 3D images. The correct position of the central sulcus was agreed by two senior neurosurgeons and one neuroradiologist. RESULTS: One of the three candidates corresponded to the central sulcus identified by the manual segmentation method for all 60 affected and unaffected hemispheres in the 30 patients. The candidate with the highest score coincided with the central sulcus in 26 of the 28 unaffected hemispheres and in 28 of the 32 affected hemispheres. CONCLUSION: The proposed method of computer-assisted image processing can provide accurate guidance to identifying the central sulcus in patients with brain tumors.

Improved geometric distortion in coronal diffusion-weighted and diffusion tensor imaging using a whole-brain isotropic-voxel acquisition technique at 3 Tesla.

PURPOSE: We used a whole-brain, isotropic-voxel acquisition technique to improve the geometric distortion in diffusion-weighted (DWI) and diffusion tensor imaging (DTI) in coronal directions, which is remarkable at high magnetic fields. MATERIALS AND METHODS: We performed magnetic resonance imaging of 17 healthy volunteers using a 3T scanner and obtained coronal DWI/DTI as well as coronal images that were reformatted from isotropic volume data acquired by 1.6-mm-thick axial DWI/DTI. We visually evaluated the degree of image distortion and quantitated the findings by co-registration analysis. RESULTS: In-plane geometric distortions in coronal DWI/DTI, particularly at the frontal base and medial temporal lobe, were dramatically diminished when the isotropic-voxel acquisition technique was used. Quantitative measurement revealed a reduction in areas of misregistration, but not their absence, in reformatted coronal images, mainly because of distortion in the anteroposterior direction in the source images. CONCLUSION: The isotropic-voxel DWI/DTI technique enabled acquisition of coronal images that represented anatomical details accurately with permissible spatial distortion while maintaining spatial resolution, even at 3T.

Primary granulomatous angiitis of the central nervous system: findings of magnetic resonance spectroscopy and fractional anisotropy in diffusion tensor imaging prior to surgery. Case report.

Primary granulomatous angiitis of the central nervous system (CNS) is extremely rare. Its preoperative diagnosis is difficult as the condition displays nonspecific features on routine neuroimaging investigations. In this paper, the authors report findings of magnetic resonance (MR) spectroscopy and fractional anisotropy (FA) with diffusion tensor MR imaging in a case of granulomatous angiitis of the CNS. A 30-year-old man presented with morning headaches and grand mal seizures. An MR image revealed a mass resembling glioblastoma in the right temporal lobe. Magnetic resonance spectroscopy showed a high choline/creatine (Cho/Cr) ratio indicative of a malignant neoplasm, accompanied by a slight elevation of glutamate and glutamine. The FA value was very low, which is inconsistent with malignant glioma. The mass was totally removed surgically. Histologically, the peripheral lesion of the mass consisted of a rough accumulation of fat granule cells, infiltration of inflammatory cells, and distribution of capillary vessels. Some vessels within the lesion were replaced by granulomas. The histological diagnosis was granulomatous angiitis of the CNS. The MIB-1-positive rate of the granuloma was approximately 5%. Both MR spectroscopy and FA were unable to accurately diagnose granulomatous angiitis of the CNS prior to surgery; however, elevated Cho/Cr and glutamate and glutamine shown by MR spectroscopy may indicate the moderate proliferation potential of the granuloma and the inflammatory process, respectively, in this condition. Although the low FA value in the present case enabled the authors to rule out a diagnosis of glioblastoma, FA values in inflammatory lesions require careful interpretation.

Preoperative imaging of superficially located glioma resection using short inversion-time inversion recovery images in high-field magnetic resonance imaging.

OBJECTIVES: Short inversion-time inversion recovery (STIR) is the only magnetic resonance imaging (MRI) sequence able to produce high contrast images of both brain-CSF and gray matter-white matter in the central nervous system. The aim of the present study is to evaluate the effectiveness of STIR in imaging tumor involvement of the cortical surface and intra-axial structures, its usefulness in the resection of superficially located gliomas. PATIENTS AND METHODS: In this study, we perform conventional MRI (1.5 T) and STIR (3.0 T) before surgery in 10 patients with superficially located glioma. We estimate the spatial relationship between the tumor bulk, the adjacent cortical surface and intra-axial structures on T2WI (1.5 T) and STIR (3.0 T). STIR findings are applied to resection of the tumor in each case. RESULTS: For all patients, STIR provided more satisfactory images than T2WI of both the cortical surface structures and intra-axial structures surrounding the tumor. During surgery, the clear demonstration of cortical surface structures on preoperative STIR images assisted in determining tumor location and the sulci to be split for the trans-sulcal approach for patients whose cortex was normal in colour. Clear contrast on STIR between the tumor margin and peritumoral edema was useful for tumor resection. CONCLUSION: STIR is able to demonstrate anatomical details of the cortical surface and intra-axial structures of the brain and is therefore suitable for the preoperative evaluation of superficially located gliomas.

Quantitative analysis of magnetic resonance imaging susceptibility artifacts caused by neurosurgical biomaterials: comparison of 0.5, 1.5, and 3.0 Tesla magnetic fields.

Magnetic resonance (MR) imaging is an important diagnostic tool for neurosurgical diseases but susceptibility artifacts caused by biomaterial instrumentation frequently causes difficulty in visualizing postoperative changes. The susceptibility artifacts caused by neurosurgical biomaterials were compared quantitatively by 0.5, 1.5, and 3.0 Tesla MR imaging. MR imaging of uniform size and shape of pieces ceramic (zirconia), pure titanium, titanium alloy, and cobalt-based alloy was performed at 0.5, 1.5, and 3.0 Tesla. A linear region of interest was defined across the center of the biomaterial in the transverse direction, and the susceptibility artifact diameter was calculated. Susceptibility artifacts developed around all biomaterials at all magnetic field strengths. The artifact diameters caused by pure titanium, titanium alloy, and cobalt-based alloy increased in the order of 0.5, 1.5, to 3.0 Tesla magnetic fields. The artifact diameter of ceramic was not influenced by magnetic field strength, and was the smallest of all biomaterials at all magnetic field strengths. The artifacts caused by biomaterials except ceramic increase with the magnetic field strength. Ceramic instrumentation will minimize artifacts in all magnetic fields.

[A case of multiple cerebral infarction accompanied by a cor triatriatum].

A cor triatriatum is a congenital malformation of the heart which, in almost all cases, is diagnosed in childhood, whereas adult cases are very rare. The hemodynamics of the cor triatriatum is similar to that of mitral stenosis, which sometimes, but rarely, causes embolism. We present a case of multiple cerebral infarctions accompanied with a cor triatriatum. A 57-year-old female suddenly displayed impaired consciousness and hemiparesis immediately after cranioplasty for another disease, and was diagnosed by a diffusion weighted MRI as having multiple infarctions. A transesophageal echocardiography detected a membrane-like, echo-dense structure across the left atrium, suggesting a cor triatriatum. We suspect that her multiple infarctions were caused by embolism due to a cor triatriatum. Here, we discuss the relationship between her embolic stroke and the cor triatriatum, with references to literature on the subject.