Dural ossification associated with cervical ossification of the posterior longitudinal ligament: frequency of dural ossification and comparison of neuroimaging modalities in ability to identify the disease

2005 ◽  
Vol 2 (4) ◽  
pp. 425-430 ◽  
Author(s):  
Junichi Mizuno ◽  
Hiroshi Nakagawa ◽  
Naoki Matsuo ◽  
Joonsuk Song
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Double Layer ◽  
Ct Scanning ◽  
Posterior Longitudinal Ligament ◽  
En Bloc ◽  
Content Type ◽  
Bone Window ◽  
Dural Ossification ◽  
Fine Print

Object. The authors' goal in this study was to understand the frequency and pattern of dural ossification (DO, and to evaluate the effectiveness of neuroimaging modalities used to identify this disease in association with ossification of the posterior longitudinal ligament (OPLL). Methods. One hundred eleven patients with OPLL underwent anterior procedures. Of these patients, 17 (15.3%) had associated ossification of the dura mater. There were 10 cases of DO in the 94 patients with segmental OPLL and seven in the 17 patients with nonsegmental OPLL (seven continuous and 10 mixed-type OPLL). Retrospective evaluation of DO was performed by examining plain x-ray films, polytomography studies, computerized tomography (CT) scans, and magnetic resonance (MR) images. A positive correlation was found between the type of OPLL and the frequency of DO (p < 0.01). The DO was classified into the following three types according to shape: 1) isolated type, 2) double-layer type, and 3) en bloc type, based on its relationship with OPLL. There were 10 lesions of the double-layer type, four en bloc type, and three isolated type; the double-layer pattern of DO was the most common. All DOs as well as OPLLs (17 cases) were identified using bone-window CT scanning. Polytomography was used successfully to identify all 12 OPLLs, whereas DO was recognized in seven of the 12 cases. Magnetic resonance imaging could not identify DO (none of the 17 cases), although OPLL was identified on MR imaging in 12 of the 17 cases. Conclusions. Three patterns of DO associated with OPLL, that is, isolated, double-layer, and en bloc types, were confirmed by retrospective analysis of neuroimaging findings. Nonsegmental OPLL was likely to be accompanied by DO. Bone-window CT scanning was most useful for identification of DO as well as OPLL, whereas MR imaging was ineffective in recognizing DO.

Magnetic resonance imaging—documented extravasation as an indicator of acute hypertensive intracerebral hemorrhage

1998 ◽  
Vol 88 (4) ◽  
pp. 650-655 ◽  
Author(s):  
Yasuo Murai ◽  
Yukio Ikeda ◽  
Akira Teramoto ◽  
Yukihide Tsuji
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Intracerebral Hemorrhage ◽  
Cerebral Angiography ◽  
Ct Scanning ◽  
Content Type ◽  
Hematoma Enlargement ◽  
Hypertensive Intracerebral Hemorrhage ◽  
Fine Print

Object. The aim of this study was to determine the usefulness of magnetic resonance (MR) imaging—documented extravasation as an indicator of continued hemorrhage in patients with acute hypertensive intracerebral hemorrhage (ICH). Methods. The authors studied 108 patients with acute hyperintensive ICH. Imaging modalities included noncontrast-enhanced computerized tomography (CT) scanning, gadolinium-enhanced MR imaging, and conventional cerebral angiography obtained within 6 hours after the onset of hemorrhage. A repeated CT scan was obtained within 48 hours to evaluate enlargement of the hematoma. Findings on MR imaging indicating extravasation, including any high-intensity signals on T1-weighted postcontrast images, were observed in 39 patients, and 17 of these also showed evidence of extravasation on cerebral angiography. The presence of extravasation on MR imaging was closely correlated with evidence of hematoma enlargement on follow-up CT scans (p < 0.001). Conclusions. Evidence of extravasation documented on MR imaging indicates persistent hemorrhage and correlates with enlargement of the hematoma.

Early magnetic resonance imaging of brainstem lesions after severe head injury

1998 ◽  
Vol 89 (5) ◽  
pp. 707-712 ◽  
Author(s):  
Raimund Firsching ◽  
Dieter Woischneck ◽  
Michael Diedrich ◽  
Susan Klein ◽  
Andreas Rückert ◽  
...  
Keyword(s):  
Head Injury ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Severe Head Injury ◽  
Auditory Evoked Potentials ◽  
Ct Scanning ◽  
Brainstem Lesion ◽  
Content Type ◽  
Brainstem Lesions ◽  
Fine Print

Object. The availability of magnetic resonance (MR) imaging data obtained in comatose patients after head injury is scarce, because MR imaging is somewhat cumbersome to perform in patients requiring ventilation and because, in the first hours after injury, its relevance is clearly inferior to computerized tomography (CT) scanning. The authors assessed the value of MR imaging in the early postinjury period. Methods. In this prospective study MR imaging was performed in 61 consecutive patients within 7 days after they suffered a severe head injury. An initial CT scan had already been obtained. To understand the clinical significance of the lesions whose morphological appearance was identified with MR imaging, brainstem function was assessed by registration of somatosensory and auditory evoked potentials. Brainstem lesions were visualized in 39 patients (64%). Bilateral pontine lesions proved to be 100% fatal and nonbrainstem lesions carried a mortality rate of 9%. In singular cases circumstances allowed for a clear clinical distinction between primary and secondary brainstem lesions. On MR imaging all lesions were hyper- and hypointense after intervals longer than 2 days. Within shorter intervals (< 2 days) after the injury, primary lesions appeared isointense on MR imaging. In one secondary brainstem lesion there were no traces of blood. Conclusions. Because mean intracranial pressure (ICP) levels in patients without brainstem lesions were similar to those in patients with brainstem lesions, the authors conclude that it was not mainly increased ICP that accounted for the high mortality rates in patients with brainstem lesions. The authors also conclude that brainstem lesions are more frequently found in severe head injury than previously reported in studies based on neuropathological or CT scanning data. Early MR imaging after head injury has a higher predictive value than CT scanning.

Magnetic resonance imaging findings in ossification of the posterior longitudinal ligament of the cervical spine

1998 ◽  
Vol 88 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Izumi Koyanagi ◽  
Yoshinobu Iwasaki ◽  
Kazutoshi Hida ◽  
Hiroyuki Imamura ◽  
Hiroshi Abe
Keyword(s):  
Magnetic Resonance Imaging ◽  
Spinal Cord ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Posterior Longitudinal Ligament ◽  
Imaging Findings ◽  
Resonance Imaging ◽  
Disc Protrusion ◽  
Content Type ◽  
Fine Print

Object. Because of the lack of magnetic resonance (MR) signal from cortical bones, MR imaging is inadequate for diagnosing ossified lesions in the spinal canal. However, MR imaging provides important information on spinal cord morphology and associated soft-tissue abnormality. The purpose of this study is to determine the role of MR imaging in the diagnosis and treatment of patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. Methods. The authors reviewed MR imaging findings in 42 patients with cervical OPLL who were examined with a superconducting MR imaging system. The types of OPLL reviewed included eight cases of continuous, 21 cases of segmental, and 13 cases of the mixed type. All patients were treated surgically either by anterior (26 cases) or posterior decompression (16 cases). Conclusions. The T1-weighted images clearly demonstrated the spinal cord deformity caused by OPLL. Associated disc protrusion was found to be present at the maximum compression level in 60% of the patients in this series. The highest incidence of disc protrusion (81%) was found in patients with segmental OPLL. Intramedullary hyperintensity on T2*-weighted imaging was noted in 18 patients (43%). The neurological deficits observed in these 18 patients were significantly more severe than those observed in the other 24 patients. Postoperative MR imaging revealed improvement in the spinal cord deformity, although the intramedullary hyperintensity was still observed in most cases. The present study demonstrates the importance of associated disc protrusion in the development of myelopathy in patients with cervical OPLL. Magnetic resonance imaging findings may be used to help determine the actual levels of spinal cord compression and to suggest the method of surgical treatment.

Effect of subpixel magnetic resonance imaging shifts on radiosurgical dosimetry for vestibular schwannoma

2002 ◽  
Vol 97 ◽  
pp. 445-449 ◽  
Author(s):  
Jonathan A. Borden ◽  
Jen-san Tsai ◽  
Anita Mahajan
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Internal Auditory Canal ◽  
Ct Scanning ◽  
Thermoluminescent Dosimetry ◽  
Content Type ◽  
Dose Volume ◽  
Treatment Plans ◽  
Small Targets ◽  
Fine Print

Object. The purpose of this study was to evaluate subpixel magnetic resonance (MR) imaging shifts of intracanalicular vestibular schwannomas (VSs) with respect to the internal auditory canal (IAC) as documented on computerized tomography (CT) scanning and to investigate the source of imaging-related localization errors in radiosurgery as well as the effect of such shifts on the dosimetry for small targets. Methods. A shift of the stereotactic coordinates of intracanalicular VSs between those determined on MR imaging and those on CT scanning represents an error in localization. A shift vector places the tumor within the IAC and measures the CT scan/MR image discrepancy. The shift vectors were measured in a series of 15 largely intracanalicular VSs (all < 1.5 cm3 in volume). Using dose volume histogram measurements, the overlap between shifted and unshifted tumors and radiosurgical treatment plans were measured. Using plastic and bone phantoms and thermoluminescent dosimetry measurements, the correspondence between CT and MR imaging targets and treatments delivered using the Leksell gamma knife were measured. Combining these measurements, the correspondence between intended and actual treatments was measured. Conclusions. The delivery of radiation to CT-imaged targets was accurate to the limits of measurement (∼ 0.1 mm). The MR imaging shifts seen in the y axis averaged 0.9 mm and in the z axis 0.8 mm. The corresponding percentage of tumor coverage with respect to apparent target shift decreased from 98 to 77%. This represents a significant potential error when targets are defined solely by MR imaging.

Histological yield, complications, and technological considerations in 114 consecutive frameless stereotactic biopsy procedures aided by open intraoperative magnetic resonance imaging

2002 ◽  
Vol 97 (2) ◽  
pp. 354-362 ◽  
Author(s):  
René L. Bernays ◽  
Spyros S. Kollias ◽  
Nadia Khan ◽  
Sebastian Brandner ◽  
Sonja Meier ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Stereotactic Biopsy ◽  
Brain Biopsy ◽  
Ct Scanning ◽  
Complication Rates ◽  
Stereotactic Brain Biopsy ◽  
Content Type ◽  
Fine Print

Object. The authors undertook a prospective study of frameless, magnetic resonance (MR)—guided stereotactic brain biopsy procedures performed with the aid of an open MR system. Morbidity and mortality rates, frequency of postoperative hemorrhage, and histological yield were evaluated, as well as the size and location of the lesions under investigation. Methods. During a period of 51 months (July 1996–November 2000), 114 consecutive frameless stereotactic biopsy procedures were performed with the aid of an open intraoperative MR system to investigate supratentorial lesions in 113 patients. The median volume of the lesions was 33.5 cm3, and 31.9% were deep seated. All biopsy samples comprised pathological tissue and in 111 (97.4%) of 114 a specific neuropathological diagnosis was made. A follow-up computerized tomography (CT) scan was obtained on the 1st postoperative day in all patients to evaluate postoperative complications. In two cases (1.8%), a hemorrhage was found on postoperative CT scans, with no neurological worsening of the patients. Morbidity with neurological worsening was seen in three patients; it was transient in two of them (1.8%), and in one (0.9%) subsequent emergency craniotomy was necessary because of increased edema. There were no infections, but there was one death (0.9%) Conclusions. Open intraoperative MR imaging transforms a blind conventional stereotactic procedure into a visually controlled procedure that is adaptable to dynamic anatomical changes. Routine postprocedural MR imaging makes follow-up CT scanning obsolete. This largest reported series of intraoperative MR—guided biopsy procedures shows results that are at least comparable with those in reports of larger series of conventional stereotactic biopsy sampling. The mean procedure time was 60 minutes including planning, and this method produced low morbidity and complication rates and a high histological yield.

Convective distribution of macromolecules in the primate brain demonstrated using computerized tomography and magnetic resonance imaging

2003 ◽  
Vol 98 (3) ◽  
pp. 584-590 ◽  
Author(s):  
Tung T. Nguyen ◽  
Yashdip S. Pannu ◽  
Cynthia Sung ◽  
Robert L. Dedrick ◽  
Stuart Walbridge ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Computerized Tomography ◽  
Ct Scanning ◽  
Therapeutic Agents ◽  
Content Type ◽  
Drug Concentrations ◽  
The Brain ◽  
Fine Print

Object. Convection-enhanced delivery (CED), the delivery and distribution of drugs by the slow bulk movement of fluid in the extracellular space, allows delivery of therapeutic agents to large volumes of the brain at relatively uniform concentrations. This mode of drug delivery offers great potential for the treatment of many neurological disorders, including brain tumors, neurodegenerative diseases, and seizure disorders. An analysis of the treatment efficacy and toxicity of this approach requires confirmation that the infusion is distributed to the targeted region and that the drug concentrations are in the therapeutic range. Methods. To confirm accurate delivery of therapeutic agents during CED and to monitor the extent of infusion in real time, albumin-linked surrogate tracers that are visible on images obtained using noninvasive techniques (iopanoic acid [IPA] for computerized tomography [CT] and Gd—diethylenetriamine pentaacetic acid for magnetic resonance [MR] imaging) were developed and investigated for their usefulness as surrogate tracers during convective distribution of a macromolecule. The authors infused albumin-linked tracers into the cerebral hemispheres of monkeys and measured the volumes of distribution by using CT and MR imaging. The distribution volumes measured by imaging were compared with tissue volumes measured using quantitative autoradiography with [14C]bovine serum albumin coinfused with the surrogate tracer. For in vivo determination of tracer concentration, the authors examined the correlation between the concentration of the tracer in brain homogenate standards and CT Hounsfield units. They also investigated the long-term effects of the surrogate tracer for CT scanning, IPA-albumin, on animal behavior, the histological characteristics of the tissue, and parenchymal toxicity after cerebral infusion. Conclusions. Distribution of a macromolecule to clinically significant volumes in the brain is possible using convection. The spatial dimensions of the tissue distribution can be accurately defined in vivo during infusion by using surrogate tracers and conventional imaging techniques, and it is expected that it will be possible to determine local concentrations of surrogate tracers in voxels of tissue in vivo by using CT scanning. Use of imaging surrogate tracers is a practical, safe, and essential tool for establishing treatment volumes during high-flow interstitial microinfusion of the central nervous system.

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.

Cervical magnetic resonance imaging abnormalities not predictive of cervical spine instability in traumatically injured patients

2004 ◽  
Vol 1 (1) ◽  
pp. 39-42 ◽  
Author(s):  
Eric M. Horn ◽  
Gregory P. Lekovic ◽  
Iman Feiz-Erfan ◽  
Volker K. H. Sonntag ◽  
Nicholas Theodore
Keyword(s):  
Cervical Spine ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Ct Scanning ◽  
Resonance Imaging ◽  
Cervical Instability ◽  
Content Type ◽  
Trauma Service ◽  
Injured Patients ◽  
Fine Print

Object. Identifying instability of the cervical spine can be difficult in traumatically injured patients. The goal of this study was to determine whether cervical abnormalities demonstrated on magnetic resonance (MR) imaging are predictive of spinal instability. Methods. Data in all patients admitted through the Level I trauma service at the authors' institution who had undergone cervical MR imaging were retrospectively reviewed. The reasons for MR imaging screening were neurological deficit, fracture, neck pain, and indeterminate clinical examination (for example, coma). Abnormal soft-tissue (prevertebral or paraspinal) findings on MR imaging were correlated with those revealed on computerized tomography (CT) scanning and plain and dynamic radiography to determine the presence/absence of cervical instability. Of 6328 patients admitted through the trauma service, 314 underwent MR imaging of the cervical spine. Of 166 patients in whom CT scanning or radiography demonstrated normal findings, 70 had undergone MR imaging that revealed abnormal findings. Of these 70 patients, 23 underwent dynamic imaging, the findings of which were normal. In each case of cervical instability (65 patients) CT, radiographic, and MR imaging studies demonstrated abnormalities. Furthermore, there were 143 patients with abnormal CT or radiographic study findings, in 13 of whom MR imaging revealed normal findings. Six of the latter underwent dynamic testing, which demonstrated normal results. Conclusions. Magnetic resonance imaging is sensitive to soft-tissue injuries of the cervical spine. When CT scanning and radiography detect no fractures or signs of instability, MR imaging does not help in determining cervical stability and may lead to unnecessary testing when not otherwise indicated.

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.

En bloc laminoplasty without dissection of paraspinal muscles

2005 ◽  
Vol 3 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Noboru Hosono ◽  
Hironobu Sakaura ◽  
Yoshihiro Mukai ◽  
Takahiro Ishii ◽  
Hideki Yoshikawa
Keyword(s):  
Ct Scanning ◽  
Cord Compression ◽  
Neck Muscle ◽  
Open Door ◽  
En Bloc ◽  
Cross Sectional ◽  
Content Type ◽  
Spinous Processes ◽  
Significant Difference ◽  
Fine Print

Object. Although conducting cervical laminoplasty in patients with multisegmental cord compression provides good neurological results, it is not without shortcomings, including C-5 palsy, axial neck pain, and undesirable radiologically detectable changes. Postoperative kyphosis and segmental instability can cause neurological problems and are believed mainly to result from neck muscle disruption. The authors developed a new laminoplasty technique, with the aim of preserving optimal muscle function. Methods. The present technique is a modification of unilateral open-door laminoplasty. By using an ultrasonic osteotome in small gaps of muscle bellies, a gutter is made without disrupting muscles, spinous processes, or their connections on the hinged side. Ceramic spacers are then positioned between elevated laminae and lateral masses at C-3, C-5, and C-7 on the opened side, which is exposed in a conventional manner. This new procedure was used to treat 37 consecutive patients with compression myelopathy. Postoperative computerized tomography (CT) scanning revealed a significant difference in a cross-sectional area of muscles between the hinged and opened side. The mean follow-up period was 40.2 months (range 24–54 months). Changes in alignment were observed in only one patient, and vertebral slippage developed in two. Performed at regular intervals, CT scanning demonstrated that the elevated laminae remained in situ throughout the study period. Conclusions. In using the present unilateral open-door laminoplasty technique, deep extensor muscles are left intact along with their junctions to spinous processes on the hinged side. Radiologically documented changes were minimal because the preserved muscles functioned normally immediately after the operation.

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