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.

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.

Localization of stimulating electrodes in patients with Parkinson disease by using a three-dimensional atlas—magnetic resonance imaging coregistration method

2003 ◽  
Vol 99 (1) ◽  
pp. 89-99 ◽  
Author(s):  
Jérôme Yelnik ◽  
Philippe Damier ◽  
Sophie Demeret ◽  
David Gervais ◽  
Eric Bardinet ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Parkinson Disease ◽  
Three Dimensional ◽  
Zona Incerta ◽  
Mr Images ◽  
Content Type ◽  
Anatomical Localization ◽  
Stimulating Electrodes ◽  
Fine Print

Object. The aim of this study was to correlate the clinical improvement in patients with Parkinson disease (PD) treated using deep brain stimulation (DBS) of the subthalamic nucleus (STN) with the precise anatomical localization of stimulating electrodes. Methods. Localization was determined by superimposing figures from an anatomical atlas with postoperative magnetic resonance (MR) images obtained in each patient. This approach was validated by an analysis of experimental and clinical MR images of the electrode, and the development of a three-dimensional (3D) atlas—MR imaging coregistration method. The PD motor score was assessed through two contacts for each of two electrodes implanted in 10 patients: the “therapeutic contact” and the “distant contact” (that is, the next but one to the therapeutic contact). Seventeen therapeutic contacts were located within or on the border of the STN, most of which were associated with significant improvement of the four PD symptoms tested. Therapeutic contacts located in other structures (zona incerta, lenticular fasciculus, or midbrain reticular formation) were also linked to a significant positive effect. Stimulation applied through distant contacts located in the STN improved symptoms of PD, whereas that delivered through distant contacts in the remaining structures had variable effects ranging from worsening of symptoms to their improvement. Conclusions. The authors have demonstrated that 3D atlas—MR imaging coregistration is a reliable method for the precise localization of DBS electrodes on postoperative MR images. In addition, they have confirmed that although the STN is the main target during DBS treatment for PD, stimulation of surrounding regions, particularly the zona incerta or the lenticular fasciculus, can also improve symptoms of PD.

A prospective comparison between three-dimensional magnetic resonance imaging and ventriculography for target-coordinate determination in frame-based functional stereotactic neurosurgery

1999 ◽  
Vol 91 (6) ◽  
pp. 911-914 ◽  
Author(s):  
P. Richard Schuurman ◽  
Rob M. A. de Bie ◽  
Charles B. L. Majoie ◽  
Johannes D. Speelman ◽  
D. Andries Bosch
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Three Dimensional ◽  
Target Area ◽  
Stereotactic Neurosurgery ◽  
Content Type ◽  
Prospective Comparison ◽  
The Mean ◽  
3D Mr Imaging ◽  
Fine Print

Object. The purpose of this prospective study was to compare stereotactic coordinates obtained with ventriculography with coordinates derived from stereotactic computer-reconstructed three-dimensional magnetic resonance (3D-MR) imaging in functional stereotactic procedures.Methods. In 15 consecutive patients undergoing functional stereotactic procedures, both preoperative frame-based stereotactic 3D-MR imaging and intraoperative ventriculography were performed. Differences between 3D-MR imaging and ventriculography in X, Y, and Z coordinates of the anterior commissure (AC), posterior commissure (PC), and target area were calculated, as well as the 3D distance between the position of AC, PC, and target within stereotactic space as obtained using both methods. The position of the stereotactic MR imaging fiducial markers measured using 3D-MR imaging compared well with the markers' known position embedded in the software (mean error 0.4 mm, maximal error for an individual slice 1.2 mm). For the individual coordinates, only for Y-PC was a difference found between 3D-MR imaging and ventriculography that significantly exceeded half the size of a pixel, the theoretical limit of precision when using a digitized imaging technique. However, the mean difference was smaller than 1 mm. The mean 3D distance between the 3D-MR imaging— and ventriculography-derived coordinates was 1.09 mm for AC, 1.13 mm for PC, and 1.29 mm for the targets.Conclusions. With these data it is shown that there is sufficient agreement between ventriculography-derived and 3D-MR imaging—derived stereotactic coordinates to justify the use of 3D-MR imaging target determination in frame-based functional stereotactic neurosurgery.

Atlantoaxial stability in ossiculum terminale

2001 ◽  
Vol 95 (1) ◽  
pp. 119-121
Author(s):  
Cheng-Loong Liang ◽  
Chun-Chung Lui ◽  
Kang Lu ◽  
Tao-Chen Lee ◽  
Han-Jung Chen
Keyword(s):  
Cervical Spine ◽  
Magnetic Resonance ◽  
Three Dimensional ◽  
Odontoid Process ◽  
Magnetic Resonance Images ◽  
The Body ◽  
Content Type ◽  
Ossiculum Terminale ◽  
Atlantoaxial Stability ◽  
Fine Print

✓ The authors describe a patient with ossiculum terminale. Thin-section three-dimensional computerized tomography reconstructions, magnetic resonance images, and radiographs of the cervical spine were obtained to evaluate the atlantoaxial stability and structures of the ossiculum terminale. Bone had formed between the ossicles and the body of the odontoid process, and good atlantoaxial stability was clearly demonstrated.

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.

A brainstem stereotactic atlas in a three-dimensional magnetic resonance imaging navigation system: first experiences with atlas-to-patient registration

1999 ◽  
Vol 90 (5) ◽  
pp. 891-901 ◽  
Author(s):  
Klaus Niemann ◽  
Roland van den Boom ◽  
Katja Haeselbarth ◽  
Farhad Afshar
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Three Dimensional ◽  
Imaging Data ◽  
Mr Images ◽  
Content Type ◽  
Patient Registration ◽  
Scale Factors ◽  
Stereotactic Atlas ◽  
Fine Print

Object. The authors describe a computer-resident digital representation of a stereotactic atlas of the human brainstem, its semiautomated registration to sagittal fast low—angle shot three-dimensional (3-D) magnetic resonance (MR) imaging data sets in 27 healthy volunteers and 24 neurosurgical patients, and an analysis of the subsequent transforms needed to refine the initial registration.Methods. Contour drawings from the atlas, which offer the 70th percentile of variation of anatomical structures, were interpolated into an isotropic 3-D representation. Initial atlas-to-patient registration was based on the fastigium/ventricular floor plane reference system. The quality of the fit was evaluated using superimposition of the atlas and MR images. If necessary, the atlas was tailored to the individual anatomy by using additional transforms. On average, the atlas had to be stretched by 2 to 6% in the three directions of space. Scale factors varied over a broad range from −8 to +19% and the benefit of visual interactive control of the atlas-to-patient registration was evident. Analysis of distances within the pons measured in the midsagittal MR imaging slices and the required scale factors revealed significant correlations that may be used to reduce the amount of user interaction in the coregistration substantially. In 70.6% of the cases, the atlas had to be shifted in a cranial direction along the brainstem axis (in 25.5% of cases 3–4 mm, in 45.1% of cases 1–2 mm). This was due to a more caudal position of the fastigium cerebelli on the MR images compared with the atlas.Conclusions. This observation, in conjunction with the variability of the height of the fourth ventricle in our MR imaging data (range 6.1–15.2 mm, mean 10.1 mm, standard deviation 1.8 mm) calls into question the role of the fastigium cerebelli as an anatomical landmark for localization within the brainstem.

Rapid identification of the primary motor area by using magnetic resonance axonography

2002 ◽  
Vol 97 (3) ◽  
pp. 558-567 ◽  
Author(s):  
Kyousuke Kamada ◽  
Kiyohiro Houkin ◽  
Yoshinobu Iwasaki ◽  
Fumiya Takeuchi ◽  
Shinya Kuriki ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Three Dimensional ◽  
Motor Area ◽  
Imaging Data ◽  
Primary Motor Area ◽  
Content Type ◽  
Normal Volunteers ◽  
Somatosensory Evoked Fields ◽  
Fine Print

Object. To identify the primary motor area (PMA) quickly and correctly, the authors used magnetic resonance (MR) axonography, including anisotropic diffusion-weighted (DW) MR imaging and three-dimensional anisotropic contrast (3DAC) imaging, which was performed to visualize the corticospinal tract mainly originating from the PMA. Methods. All studies were obtained in 10 normal volunteers and in 17 patients with brain tumors affecting the central motor system. Data sets of anisotropic DW imaging and anatomical and functional (f)MR imaging were acquired while the participants executed simple hand movements. Offline processing of 3DAC MR axonography images was subsequently done to extract only the anisotropic components of the tract fibers. Somatosensory evoked fields (SSEFs) and intraoperative cortical somatosensory evoked potentials (SSEPs) were recorded after electrical stimulation of the median nerve. Conclusions. In normal volunteers, anisotropic DW imaging, 3DAC imaging, fMR imaging, and magnetoencephalography consistently localized the PMA in both hemispheres. In contrast, fMR imaging and SSEFs failed to identify the PMA in seven and one of the 17 patients, respectively, because of cortical dysfunctions due to brain tumor. The anisotropic DW imaging data acquired within 30 seconds with no patient tasks successfully identified the PMA in 12 patients, and failed in five patients because of the lesions involving the frontal lobe. The anisotropic axonal components were distinctly visualized on 3DAC images and indicated the PMA location, which was confirmed on intraoperative SSEPs in all 17 affected hemispheres. Swift and noninvasive PMA identification by rapid scanning with MR axonography is a promising method for routine clinical use and is especially beneficial for patients who have severe cortical dysfunction in the PMA.

Detailed magnetic resonance imaging anatomy of the cisternal segment of the abducent nerve: Dorello's canal and neurovascular relationships and landmarks

1999 ◽  
Vol 91 (2) ◽  
pp. 276-283 ◽  
Author(s):  
Indra Yousry ◽  
Salvador Camelio ◽  
Martin Wiesmann ◽  
Urs D. Schmid ◽  
Bernhard Moriggl ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Three Dimensional ◽  
Anterior Inferior Cerebellar Artery ◽  
Content Type ◽  
Dorello’S Canal ◽  
Imaging Sequence ◽  
Cerebellar Artery ◽  
Abducent Nerve ◽  
Fine Print

Object. The goal of this study was to identify reliably the cisternal segment of the abducent nerve by using the three-dimensional Fourier transform constructive interference in steady-state (3-D CISS) magnetic resonance (MR) imaging sequence to define landmarks that assist in the identification of the abducent nerve on MR imaging and to describe the nerve's relationship to the anterior inferior cerebellar artery (AICA).Methods. A total of 26 volunteers underwent 3-D CISS MR imaging, and 10 of these volunteers also underwent MR angiography in which a time-of-flight sequence was used to identify the facial colliculus, the abducent nerve and its apparent origin, Dorello's canal, and the AICA.The authors identified the abducent nerve with certainty in 96% of 3-D CISS sequences obtained in the axial and sagittal planes and in 94% obtained in the coronal plane. The nerve emerged from the pontomedullary sulcus in 94% of cases. The facial colliculus could always be identified, and Dorello's canal was identified in 94% of cases. In 76.6% of cases, the abducent nerve was seen to contact the AICA, which passed inferior to the nerve in 63.8% of cases and superior to it in 29.8%.Conclusions. The anatomical course of the abducent nerve and its relationship to the AICA and other blood vessels can be reliably identified using a 3-D CISS MR sequence with the facial colliculus and Dorello's canal serving as landmarks.

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.

Effects of coregistration of MR to CT images on MR stereotactic accuracy

1995 ◽  
Vol 82 (5) ◽  
pp. 772-779 ◽  
Author(s):  
Douglas S. Cohen ◽  
Jonathan H. Lustgarten ◽  
Erik Miller ◽  
Alexander G. Khandji ◽  
Robert R. Goodman
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Ct Scan ◽  
Three Dimensional ◽  
Mr Images ◽  
Dimensional Error ◽  
Content Type ◽  
Multiplanar Imaging ◽  
Anatomical Detail ◽  
Fine Print

✓ Coregistration of different modality imaging serves to increase the ease and accuracy of stereotactic procedures. In many cases, magnetic resonance (MR) stereotaxis is supplanting computerized tomography (CT). The advantages of increased anatomical detail and multiplanar imaging afforded by MR, however, are offset by its potential inaccuracy as well as the more cumbersome and less available nature of its hardware. A system has been developed by one of the authors by which MR imaging can be performed separately without a stereotactic fiducial headring. Then, immediately prior to surgery, a stereotactic CT scan is obtained and software is used to coregister CT and MR images anatomically by matching cranial landmarks in the two scans. The authors examined this system in six patients as well as with the use of a lucite phantom. After initially coregistering CT and MR images, six separate anatomical (for the patients) and eight artificial (for the phantom) targets were compared. With coregistration, in comparison to CT fiducial scans, errors in each axis are less than or equal to 1 mm using the Cosman-Roberts-Wells system. In fact, the coregistered images are more accurate than MR fiducial images, in the anteroposterior (p = 0.001), lateral (p < 0.05), and vertical (p < 0.03) planes. Three-dimensional error was significantly less in the coregistered scans than the MR fiducial images (p < 0.005). The coregistration procedure therefore not only increases the ease of MR stereotaxis but also increases its accuracy.

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