High-field magnetic resonance imaging in patients with moyamoya disease

2001 ◽  
Vol 94 (2) ◽  
pp. 233-237 ◽  
Author(s):  
Atsuko Harada ◽  
Yukihiko Fujii ◽  
Yuichiro Yoneoka ◽  
Shigekazu Takeuchi ◽  
Ryuichi Tanaka ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Healthy Volunteers ◽  
Moyamoya Disease ◽  
Cerebral Circulation ◽  
High Field ◽  
Magnetic Resonance Images ◽  
Cerebral Hypoperfusion ◽  
Content Type ◽  
Fine Print

Object. The purpose of this study was to assess the utility of high-field magnetic resonance (MR) imaging as a quantitative tool for estimating cerebral circulation in patients with moyamoya disease. Methods. Eighteen patients with moyamoya disease who were scheduled to undergo revascularization surgery and 100 healthy volunteers were examined using T2-reversed MR imaging performed using a 3-tesla system. Ten of the 18 patients underwent a second study between 1 year and 3 years after revascularization. Magnetic resonance images obtained in the patients with moyamoya disease were statistically analyzed and compared with those obtained in healthy volunteers. The MR imaging findings were also correlated with results of single-photon emission computerized tomography and conventional cerebral angiography studies. Transverse lines in the white matter (medullary streaks) were observed in almost all persons. In healthy volunteers, the diameter sizes of the medullary streaks increased significantly with age (p < 0.001). Multiple logistic regression analysis revealed that age-adjusted medullary streak diameters were significantly larger in patients with moyamoya disease (p < 0.001). Diameter sizes also increased significantly with the increased severity of cerebral hypoperfusion (p < 0.001) and a higher angiographically determined stage of the disease (p < 0.001). Diameter sizes decreased significantly after surgery (p < 0.001). Conclusions. The increases in medullary streak diameters observed in patients with moyamoya disease appear to represent vessels dilated due to cerebral hypoperfusion. High-field T2-reversed MR imaging is useful in estimating cerebral circulation in patients with moyamoya disease.

Quantification of susceptibility artifacts produced on high-field magnetic resonance images by various biomaterials used for neurosurgical implants

2002 ◽  
Vol 97 (6) ◽  
pp. 1472-1475 ◽  
Author(s):  
Hideki Matsuura ◽  
Takashi Inoue ◽  
Hiromu Konno ◽  
Makoto Sasaki ◽  
Kuniaki Ogasawara ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Titanium Alloy ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
High Field ◽  
Pure Titanium ◽  
Magnetic Resonance Images ◽  
Susceptibility Artifacts ◽  
Content Type ◽  
Fine Print

✓ Although various biomaterials such as ceramics or titanium alloy are widely used in neurosurgery, the susceptibility artifacts that appear around these materials cause problems when a magnetic resonance (MR) imager is used to assess lesions after surgery. The purpose of the present study was to quantify the susceptibility artifacts produced by various biomaterials used for neurosurgical implants. Using a 3-tesla MR imaging unit, we obtained MR images of various biomaterials, including six types of ceramics, a cobalt-based alloy (Elgiloy), pure titanium, a titanium alloy, and stainless steel. All implants shared a uniform size and shape. In each image, a linear region of interest was defined across the center of the biomaterial in the transverse direction, and the diameter of the susceptibility artifact was calculated. The ceramics produced a considerably smaller artifact diameter than those produced by other biomaterials. Among the types of ceramics, zirconia was found to produce the smallest artifact diameter. Among the remaining biomaterials, the diameters of the artifacts decreased in order from that associated with stainless steel to those associated with cobalt-based alloys, pure titanium, and titanium alloy. Little difference was observed between the artifact diameters associated with pure titanium and titanium alloy. Ceramics are the most suitable biomaterials for minimizing artifacts in high-field MR imaging.

Analysis of aqueductal cerebrospinal fluid flow after endoscopic aqueductoplasty by using cine phase-contrast magnetic resonance imaging

2000 ◽  
Vol 93 (2) ◽  
pp. 237-244 ◽  
Author(s):  
Henry W. S. Schroeder ◽  
Christiane Schweim ◽  
Klaus H. Schweim ◽  
Michael R. Gaab
Keyword(s):  
Cerebrospinal Fluid ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Healthy Volunteers ◽  
Phase Contrast ◽  
Aqueductal Stenosis ◽  
Csf Flow ◽  
Content Type ◽  
Endoscopic Aqueductoplasty ◽  
Fine Print

Object. The purpose of this prospective study was to evaluate aqueductal cerebrospinal fluid (CSF) flow after endoscopic aqueductoplasty. In all patients, preoperative magnetic resonance (MR) imaging revealed hydrocephalus caused by aqueductal stenosis and lack of aqueductal CSF flow.Methods. In 14 healthy volunteers and in eight patients with aqueductal stenosis who had undergone endoscopic aqueductoplasty, aqueductal CSF flow was investigated using cine cardiac-gated phase-contrast MR imaging. For qualitative evaluation of CSF flow, the authors used an in-plane phase-contrast sequence in the midsagittal plane. The MR images were displayed in a closed-loop cine format. Quantitative through-plane measurements were performed in the axial plane perpendicular to the aqueduct. Evaluation revealed no significant difference in aqueductal CSF flow between healthy volunteers and patients with regard to temporal parameters, CSF peak and mean velocities, mean flow, and stroke volume. All restored aqueducts have remained patent 7 to 31 months after surgery.Conclusions. Aqueductal CSF flow after endoscopic aqueductoplasty is similar to aqueductal CSF flow in healthy volunteers. The data indicate that endoscopic aqueductoplasty seems to restore physiological aqueductal CSF flow.

Dynamic examination of the lumbar spine by using vertical, open magnetic resonance imaging

2000 ◽  
Vol 93 (1) ◽  
pp. 58-64 ◽  
Author(s):  
Hans-Ekkehart Vitzthum ◽  
Alexander König ◽  
Volker Seifert
Keyword(s):  
Lumbar Spine ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Healthy Volunteers ◽  
Degenerative Spondylolisthesis ◽  
Content Type ◽  
Degenerative Disorders ◽  
Lower Lumbar Spine ◽  
Dynamic Examination ◽  
Fine Print

Object. The aim of this study was to determine the relationship of different structures of the lower lumbar spine during interventional movement examination. Methods. Clinically healthy volunteers and patients suffering from degenerative disorders of the lumbar spine underwent vertical, open magnetic resonance (MR) imaging (0.5 tesla). Three functional patterns of lumbar spine motion were identified in 50 healthy volunteers, (average age 25 years). The authors identified characteristic angles of the facet joints, as measured in the frontal plane. In 50 patients with degenerative disorders of the lumbar spine (41 with disc herniation, five with osteogenic spinal stenosis, and four with degenerative spondylolisthesis) the range of rotation was increased in the relevant spinal segments. Signs of neural compression were increased under motion. Conclusions. Dynamic examination in which vertical, open MR imaging is used demonstrated that the extent of neural compression as well as the increasing range of rotation are important signs of segmental instability.

Distortion in magnetic resonance images obtained for stereotactic localization

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 191-192 ◽  
Author(s):  
Lee Walton ◽  
Anna Hampshire ◽  
Paul Vaughan ◽  
David M. C. Forster ◽  
Andras A. Kemeny ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Three Dimensional ◽  
Magnetic Resonance Images ◽  
Side Plate ◽  
Content Type ◽  
Potential Source ◽  
Minimal Distortion ◽  
Source Of Error ◽  
Fine Print

✓ The purpose of this paper was to note a potential source of error in magnetic resonance (MR) imaging. Magnetic resonance images were acquired for stereotactic planning for GKS of a vestibular schwannoma in a female patient. The images were acquired using three-dimensional sequence, which has been shown to produce minimal distortion effects. The images were transferred to the planning workstation, but the coronal images were rejected. By examination of the raw data and reconstruction of sagittal images through the localizer side plate, it was clearly seen that the image of the square localizer system was grossly distorted. The patient was returned to the MR imager for further studies and a metal clasp on her brassiere was identified as the cause of the distortion.

In vitro high-field magnetic resonance imaging—documented anatomy of a fetal myelomeningocele at 20 weeks' gestation. A contribution to the rationale of intrauterine surgical repair of spina bifida

2003 ◽  
Vol 98 (2) ◽  
pp. 210-214 ◽  
Author(s):  
Emile A. M. Beuls ◽  
Linda Vanormelingen ◽  
Jasper van Aalst ◽  
Marjan Vandersteen ◽  
Peter Adriaensens ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Magnetic Resonance ◽  
Spina Bifida ◽  
Mr Imaging ◽  
High Field ◽  
Content Type ◽  
Gestation Age ◽  
High Field Mr ◽  
Fine Print

Object. It remains uncertain if closure of a myelomeningocele at midgestation changes the neurological condition at birth in an infant born with spina bifida. The authors conducted a study to provide a detailed analysis of the morphology of the spinal cord with the myelomeningocele at the time fetal surgery usually is performed. Methods. The myelomeningocele of a 20-week-gestation-age fetus was examined, and data were compared with those obtained in a neurologically intact specimen of the same age. In vitro high-field 9.4-tesla magnetic resonance (MR) microscopy was used to examine the fetal material. High-field MR spectroscopy provided images in the three orthogonal planes with a resolution comparable with low-power optical microscopy. The authors observed that the fetal cord of the myelomeningocele specimen was tapered and tethered at S3–4 while the conus medullaris in the normal fetus reaches L-4. No neurulation defects were noted. The axial MR images clearly revealed the nonfusion of the mesodermal structures. The absence of neurulation defects suggests that at least in some cases of spina bifida the spinal cord initially is well developed but is damaged later on chemically and mechanically. This might be an argument in favor of intrauterine myelomeningocele repair. By 20 weeks' gestation, however, the deformation of the cord inside the myelomeningocele is severe. An optimization of the preoperative assessment by means of MR imaging therefore might be considered a valuable contribution to intrauterine surgery. The in vitro high-field MR microscopic findings of this study could be used as references for clinical intrauterine MR imaging. Conclusions. The detailed in vitro high-field MR analysis of a 20-week-gestation-age fetus with spina bifida demonstrated that an improvement of the preoperative intrauterine imaging should be pursued to detect those cases without neurulation defects and with minimal deformation of the spinal cord.

Asymptomatic microbleeds in moyamoya disease: T2*-weighted gradient-echo magnetic resonance imaging study

2005 ◽  
Vol 102 (3) ◽  
pp. 470-475 ◽  
Author(s):  
Ken-Ichiro Kikuta ◽  
Yasushi Takagi ◽  
Kazuhiko Nozaki ◽  
Takashi Hanakawa ◽  
Tsutomu Okada ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Moyamoya Disease ◽  
Imaging Study ◽  
Mr Studies ◽  
3 Tesla ◽  
Healthy Individuals ◽  
Gradient Echo ◽  
Content Type ◽  
Fine Print

Object. The aim of this study was to investigate the incidence of asymptomatic microbleeds (MBs) in patients with moyamoya disease (MMD) by using a 3-tesla magnetic resonance (MR) imaging unit. Methods. Data on 63 patients hospitalized with MMD between 1999 and 2004 were retrospectively examined to determine the incidence of asymptomatic MBs. Gradient-echo T2*-weighted MR imaging studies obtained using 3- and 1.5-tesla units were available in 25 patients. These patients consisted of five men and 20 women, ranging in age from 17 to 66 years (mean age 41 ± 14 years). Ischemic MMD was diagnosed in 18 patients, and hemorrhagic MMD in seven. The incidence of MBs was also evaluated using the same 3-tesla MR imaging unit in 34 healthy volunteers including seven men and 27 women, ranging in age from 18 to 71 years (mean age 33 ± 12 years). Using the 3-tesla MR unit, asymptomatic MBs were demonstrated in 11 patients (44%); they were detected in seven patients (28%) by using the 1.5-tesla unit. In the 3-tesla MR studies in healthy individuals, MBs were found in two patients (5.8%). Based on 3-tesla MR studies, the incidence of MBs was significantly higher in patients with MMD compared with that in healthy individuals. Asymptomatic MBs were demonstrated in eight (44%) of 18 patients with ischemic MMD and three (43%) of seven patients with hemorrhagic MMD. Conclusions. Microbleeds are significantly more common in patients with MMD than in healthy individuals regardless of the disease type. The evaluation of MBs with T2*-weighted 3-tesla MR imaging might contribute to the treatment of MMD.

Preoperative and postoperative mapping of cerebrovascular reactivity in moyamoya disease by using blood oxygen level—dependent magnetic resonance imaging

2005 ◽  
Vol 103 (2) ◽  
pp. 347-355 ◽  
Author(s):  
David J. Mikulis ◽  
Gregory Krolczyk ◽  
Hubert Desal ◽  
William Logan ◽  
Gabrielle deVeber ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Moyamoya Disease ◽  
Vascular Reactivity ◽  
Superficial Temporal Artery ◽  
Cerebrovascular Reactivity ◽  
Surgical Revascularization ◽  
Content Type ◽  
End Tidal ◽  
Fine Print

Object. The ability to map cerebrovascular reactivity (CVR) at the tissue level in patients with moyamoya disease could have considerable impact on patient management, especially in guiding surgical intervention and assessing the effectiveness of surgical revascularization. This paper introduces a new noninvasive magnetic resonance (MR) imaging—based method to map CVR. Preoperative and postoperative results are reported in three cases to demonstrate the efficacy of this technique in assessing vascular reserve at the microvascular level. Methods. Three patients with angiographically confirmed moyamoya disease were evaluated before and after surgical revascularization. Measurements of CVR were obtained by rapidly manipulating end-tidal PCO2 between hypercapnic and hypocapnic states during MR imaging. The CVR maps were then calculated by comparing the percentage of changes in MR signal with changes in end-tidal PCO2. Presurgical CVR maps showed distinct regions of positive and negative reactivity that correlated precisely with the vascular territories supplied by severely narrowed vessels. Postsurgical reactivity maps demonstrated improvement in the two patients with positive clinical outcome and no change in the patient in whom a failed superficial temporal artery—middle cerebral artery bypass was performed. Conclusions. Magnetic imaging—based CVR mapping during rapid manipulation of end-tidal PCO2 is an exciting new method for determining the location and extent of abnormal vascular reactivity secondary to proximal large-vessel stenoses in moyamoya disease. Although the study group is small, there seems to be considerable potential for guiding preoperative decisions and monitoring efficacy of surgical revascularization.

Detection of hyperacute subarachnoid hemorrhage of the brain by using magnetic resonance imaging

2002 ◽  
Vol 96 (4) ◽  
pp. 684-689 ◽  
Author(s):  
Martin Wiesmann ◽  
Thomas E. Mayer ◽  
Indra Yousry ◽  
Ralph Medele ◽  
Gerhard F. Hamann ◽  
...  
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
High Field ◽  
Ct Scanning ◽  
Proton Density ◽  
Imaging Protocol ◽  
Content Type ◽  
Cerebrospinal Fluid Flow ◽  
Fine Print

Object. The purpose of this study was to determine the diagnostic accuracy of high-field (1.5-tesla) magnetic resonance (MR) imaging in the assessment of hyperacute (< 12 hours after onset of symptoms) subarachnoid hemorrhage (SAH). Methods. This investigation included 13 patients who were examined 2 to 12 hours posthemorrhage by using an MR imaging protocol consisting of T2-weighted and proton-density (PD)-weighted images, T1-weighted images, fast echoplanar—diffusion-weighted (EP-DW) images, and fluid-attenuated inversion-recovery (FLAIR) images. Subarachnoid hemorrhage had been diagnosed using computerized tomography (CT) scanning in all cases. In all 13 cases, SAH was reliably detected on both PD-weighted and FLAIR images. In contrast with FLAIR studies, the PD-weighted images were free of cerebrospinal fluid flow artifacts. The SAH was detected on T1-weighted images in only two cases and could not be detected on any T2-weighted or EP-DW images. Conclusions. Even hyperacute SAH can be diagnosed reliably from high-field MR images obtained using PD-weighted or FLAIR sequences. Use of these sequences in an emergency MR protocol may preclude the need for additional CT studies to rule out SAH.

Magnetic resonance evaluation of ventrolateral medullary compression in essential hypertension

1998 ◽  
Vol 88 (2) ◽  
pp. 226-231 ◽  
Author(s):  
Gary P. Colón ◽  
Douglas J. Quint ◽  
Lawrence D. Dickinson ◽  
James A. Brunberg ◽  
Kenneth A. Jamerson ◽  
...  
Keyword(s):  
Essential Hypertension ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Magnetic Resonance Images ◽  
Control Group ◽  
Neurogenic Hypertension ◽  
Content Type ◽  
Thin Slice ◽  
Significant Difference ◽  
Fine Print

Object. The authors designed a blinded prospective study comparing patients with essential hypertension to patients without hypertension in which magnetic resonance (MR) imaging was used to evaluate the role of lateral medullary compression by adjacent vascular structures as a cause of neurogenic hypertension. Methods. Patients with documented essential hypertension were recruited to undergo thin-slice axial brainstem MR imaging evaluation. Nonhypertensive (control) patients scheduled to undergo MR imaging for other reasons also underwent thin-slice MR imaging to form a basis for comparison. Magnetic resonance images obtained in patients from the hypertensive (30 patients) and the control (45 patients) groups were then compared by four independent reviewers (two neuroradiologists and two neurosurgeons) who were blinded to the patients' diagnosis and hypertensive status. Images were reviewed with regard to left versus right vertebral artery (VA) dominance, compression of the medulla on the left and/or right side, and brainstem rotation. Medullary compression was graded as either vessel contact without associated brainstem deformity or vessel contact with associated brainstem deformity. Conclusions. There was a tendency toward left VA dominance in the hypertensive group compared with the control group, although a significant difference was shown by only one of the four reviewers. There were no differences in brainstem compression or rotation between the hypertensive and nonhypertensive groups. These results are contrary to those of recently published studies in which MR imaging and/or MR angiography revealed lateral brainstem vascular compression in hypertensive patients but not in nonhypertensive (control) patients. Reasons for this discrepancy are discussed. On the basis of their own experience and that of others, the authors believe that neurogenic hypertension does exist. However, thin-slice MR imaging may not be a reliable method for detecting neurovascularly induced essential hypertension and the prevalence of neurovascular compression as the source of hypertension may be overestimated when using current imaging techniques.

Early changes measured by magnetic resonance imaging in cerebral blood flow, blood volume, and blood-brain barrier permeability following dexamethasone treatment in patients with brain tumors

1999 ◽  
Vol 90 (2) ◽  
pp. 300-305 ◽  
Author(s):  
Leif Østergaard ◽  
Fred H. Hochberg ◽  
James D. Rabinov ◽  
A. Gregory Sorensen ◽  
Michael Lev ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Brain Tumors ◽  
Mr Imaging ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Clinical Effects ◽  
Content Type ◽  
Fine Print

Object. In this study the authors assessed the early changes in brain tumor physiology associated with glucocorticoid administration. Glucocorticoids have a dramatic effect on symptoms in patients with brain tumors over a time scale ranging from minutes to a few hours. Previous studies have indicated that glucocorticoids may act either by decreasing cerebral blood volume (CBV) or blood-tumor barrier (BTB) permeability and thereby the degree of vasogenic edema.Methods. Using magnetic resonance (MR) imaging, the authors examined the acute changes in CBV, cerebral blood flow (CBF), and BTB permeability to gadolinium-diethylenetriamine pentaacetic acid after administration of dexamethasone in six patients with brain tumors. In patients with acute decreases in BTB permeability after dexamethasone administration, changes in the degree of edema were assessed using the apparent diffusion coefficient of water.Conclusions. Dexamethasone was found to cause a dramatic decrease in BTB permeability and regional CBV but no significant changes in CBF or the degree of edema. The authors found that MR imaging provides a powerful tool for investigating the pathophysiological changes associated with the clinical effects of glucocorticoids.

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