Temporal characteristics of radiosurgical lesions in an animal model

1994 ◽  
Vol 80 (6) ◽  
pp. 1046-1055 ◽  
Author(s):  
David R. Blatt ◽  
William A. Friedman ◽  
Frank J. Bova ◽  
Daniel P. Theele ◽  
J. Parker Mickle
Keyword(s):  
Mr Imaging ◽  
Mass Effect ◽  
Intermediate Stage ◽  
Neurological Deficits ◽  
Blue Dye ◽  
Content Type ◽  
Vascular Proliferation ◽  
Peripheral Areas ◽  
Histopathological Studies ◽  
Fine Print

✓ To characterize the temporal course of radiosurgical lesions, 19 cats were irradiated in an animal linear accelerator radiosurgical device. The animals were followed clinically and, at 3.5, 6, 12, 18, 23, 29, and 63 weeks, were studied with gadolinium-enhanced magnetic resonance (MR) imaging. They were then sacrificed after Evans blue dye perfusion, and gross pathological and histopathological studies were performed. Mild neurological deficits developed between 3.5 and 4.5 weeks, correlating with the onset of mass effect both grossly and radiographically and with the maximum amount of white matter edema on T2-weighted MR imaging and microscopic examination. Clinical improvement occurred within several weeks as these resolved. The lesions were of similar size at all time intervals. Gadolinium-enhanced MR imaging demonstrated lesions with peripheral areas of enhancement and central nonenhancing regions which correlated histologically with areas of vascular proliferation and radiation necrosis, respectively. In the early lesions at 3.5 and 6 weeks, necrosis and edema were predominant. From 12 to 29 weeks, an intermediate stage was observed, with resorption of the necrotic debris as evidenced by progressive cavitation and microglial response and by increased perilesional vascularity. At 63 weeks, resorption was still taking place, but gliosis and diminution of the vascular response were seen.

A fatal, chronically growing basilar artery: a new type of dissecting aneurysm

1996 ◽  
Vol 84 (6) ◽  
pp. 962-971 ◽  
Author(s):  
Tohru Mizutani
Keyword(s):  
Mr Imaging ◽  
Basilar Artery ◽  
Dissecting Aneurysm ◽  
Neurological Deficits ◽  
Vertebrobasilar Insufficiency ◽  
Content Type ◽  
Asymptomatic Patients ◽  
Basilar Arteries ◽  
Fine Print

✓ A long-term follow-up study (minimum duration 2 years) was made of 13 patients with tortuous dilated basilar arteries. Of these, five patients had symptoms related to the presence of such arteries. Symptoms present at a very early stage included vertebrobasilar insufficiency in two patients, brainstem infarction in two patients, and left hemifacial spasm in one patient. Initial magnetic resonance (MR) imaging in serial slices of basilar arteries obtained from the five symptomatic patients showed an intimal flap or a subadventitial hematoma, both of which are characteristic of a dissecting aneurysm. In contrast, the basilar arteries in the eight asymptomatic patients did not show particular findings and they remained clinically and radiologically silent during the follow-up period. All of the lesions in the five symptomatic patients gradually grew to fantastic sizes, with progressive deterioration of the related clinical symptoms. Dilation of the basilar artery was consistent with hemorrhage into the “pseudolumen” within the laminated thrombus, which was confirmed by MR imaging studies. Of the five symptomatic patients studied, two died of fatal subarachnoid hemorrhage (SAH) and two of brainstem compression; the fifth patient remains alive without neurological deficits. In the three patients who underwent autopsy, a definite macroscopic double lumen was observed in both the proximal and distal ends of the aneurysms within the layer of the thickening intima. Microscopically, multiple mural dissections, fragmentation of internal elastic lamina (IEL), and degeneration of media were diffusely observed in the remarkably extended wall of the aneurysms. The substantial mechanism of pathogenesis and enlargement in the symptomatic, highly tortuous dilated artery might initially be macroscopic dissection within a thickening intima and subsequent repetitive hemorrhaging within a laminated thrombus in the pseudolumen combined with microscopic multiple mural dissections on the basis of a weakened IEL. The authors note and caution that symptomatic, tortuous dilated basilar arteries cannot be overlooked because they include a group of malignant arteries that may grow rapidly, resulting in a fatal course.

Intramedullary ependymoma of the spinal cord

1990 ◽  
Vol 72 (4) ◽  
pp. 523-532 ◽  
Author(s):  
Paul C. McCormick ◽  
Roland Torres ◽  
Kalmon D. Post ◽  
Bennett M. Stein
Keyword(s):  
Spinal Cord ◽  
Mr Imaging ◽  
Tumor Recurrence ◽  
Neurological Deficits ◽  
Functional Improvement ◽  
Consecutive Series ◽  
Intramedullary Spinal Cord ◽  
Content Type ◽  
Fine Print

✓ A consecutive series of 23 patients underwent operative removal of an intramedullary spinal cord ependymoma between January, 1976, and September, 1988. Thirteen women and 10 men between the age of 19 and 70 years experienced symptoms for a mean of 34 months preceding initial diagnosis. Eight patients had undergone treatment prior to tumor recurrence and referral. Mild neurological deficits were present in 22 patients on initial examination. The location of the tumors was predominantly cervical or cervicothoracic. Radiological evaluation revealed a wide spinal cord in all cases. Magnetic resonance (MR) imaging was the single most important radiological procedure. At operation, a complete removal was achieved in all patients. No patient received postoperative radiation therapy. Histological examination revealed a benign ependymoma in all cases. The follow-up period ranged from 6 to 159 months (mean 62 months) with seven patients followed for a minimum of 10 years after surgery. Fourteen patients underwent postoperative MR imaging at intervals ranging from 8 months to 10 years postoperatively. No patient has been lost to follow-up review and there were no deaths. No patient showed definite clinical or radiological evidence of tumor recurrence during the follow-up period. Recent neurological evaluation revealed functional improvement from initial preoperative clinical status in eight patients, no significant change in 12 patients, and deterioration in three patients. The data support the belief that long-term disease-free control of intramedullary spinal ependymomas with acceptable morbidity may be achieved utilizing microsurgical removal alone.

The efficacy of endosaccular aneurysm occlusion in alleviating neurological deficits produced by mass effect

1994 ◽  
Vol 80 (4) ◽  
pp. 659-666 ◽  
Author(s):  
Van V. Halbach ◽  
Randall T. Higashida ◽  
Christopher F. Dowd ◽  
Stanley L. Barnwell ◽  
Kenneth W. Fraser ◽  
...  
Keyword(s):  
Mass Effect ◽  
Response To Therapy ◽  
Neurological Deficits ◽  
Parent Artery ◽  
Duration Of Symptoms ◽  
Content Type ◽  
Neurological Signs ◽  
Wall Calcification ◽  
Aneurysm Occlusion ◽  
Fine Print

✓ Endovascular obliteration of intracranial aneurysms with preservation of the parent artery (endosaccular occlusion) has been advocated for patients who fail or are excluded from surgical clipping and cannot undergo Hunterian ligation therapy. To clarify the effect that endosaccular occlusion has on the presenting neurological signs, 26 patients with aneurysms and symptoms related to mass effect who underwent this therapy were followed for a mean of 60 months. Only patients with objective neurological deficits who had not suffered a hemorrhage were included in this series. Response to therapy was classified into one of three groups: “resolved,” if the patient had complete resolution of presenting signs; “improved,” if significant and sustained improvement was recorded in the neurological examinations, and “unchanged,” if no change was observed. Thirteen patients (50%) were classified as resolved, 11 (42.3%) as improved, and two (7.7%) as unchanged. A comparison of patients classified as resolved with those who were improved revealed that the former group had less wall calcification (30% vs. 60%) and a shorter duration of symptoms. Patients with neurological sign resolution (62%) were more likely to have totally occluded aneurysms on late follow-up arteriograms than those who had improvement (28%) or were unchanged (0%). This study suggests that endosaccular embolization therapy can improve or alleviate presenting neurological signs unrelated to hemorrhage or distal embolization in the majority of cases.

Risk of early closed reduction in cervical spine subluxation injuries

1999 ◽  
Vol 90 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Gerald A. Grant ◽  
Sohail K. Mirza ◽  
Jens R. Chapman ◽  
H. Richard Winn ◽  
David W. Newell ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Mr Imaging ◽  
Disc Herniation ◽  
Closed Reduction ◽  
Spinal Cord Injuries ◽  
Spinal Injury ◽  
Neurological Deterioration ◽  
Neurological Deficits ◽  
Content Type ◽  
Fine Print

Object. The authors retrospectively reviewed 121 patients with traumatic cervical spine injuries to determine the risk of neurological deterioration following early closed reduction. Methods. After excluding minor fractures and injuries without subluxation, the medical records and imaging studies (computerized tomography and magnetic resonance [MR] images) of 82 patients with bilateral and unilateral locked facet dislocations, burst fractures, extension injuries, or miscellaneous cervical fractures with subluxation were reviewed. Disc injury was defined on MR imaging as the presence of herniation or disruption: a herniation was described as deforming the thecal sac or nerve roots, and a disruption was defined as a disc with high T2-weighted signal characteristics in a widened disc space. Fifty-eight percent of patients presented with complete or incomplete spinal cord injuries. Thirteen percent of patients presented with a cervical radiculopathy, 22% were intact, and 9% had only transient neurological deficits in the field. Early, rapid closed reduction, using serial plain radiographs or fluoroscopy and Gardner—Wells craniocervical traction, was achieved in 97.6% of patients. In two patients (2.4%) closed reduction failed and they underwent emergency open surgical reduction. The average time to achieve closed reduction was 2.1 ± 0.24 hours (standard error of the mean). The incidence of disc herniation and disruption in the 80 patients who underwent postreduction MR imaging was 22% and 24%, respectively. However, the presence of disc herniation or disruption did not affect the degree of neurological recovery, as measured by American Spinal Injury Association motor score and the Frankel scale following early closed reduction. Only one (1.3%) of 80 patients deteriorated, but that occurred more than 6 hours following closed reduction. Conclusions. Although disc herniation and disruption can occur following all types of traumatic cervical fracture subluxations, the incidence of neurological deterioration following closed reduction in these patients is rare. The authors recommend early closed reduction in patients presenting with significant motor deficits without prior MR imaging.

Stereotactic radiosurgery of cavernous malformations

2000 ◽  
Vol 93 (6) ◽  
pp. 987-991 ◽  
Author(s):  
Bruce E. Pollock ◽  
Yolanda I. Garces ◽  
Scott L. Stafford ◽  
Robert L. Foote ◽  
Paula J. Schomberg ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Mr Imaging ◽  
Stereotactic Radiosurgery ◽  
Lesion Size ◽  
Neurological Deficits ◽  
Morbidity Rate ◽  
Cavernous Malformations ◽  
Content Type ◽  
Latency Interval ◽  
Fine Print

Object. The use of stereotactic radiosurgery to treat cerebral cavernous malformations (CMs) is controversial. To evaluate the efficacy and safety of CM radiosurgery, the authors reviewed the experience at the Mayo Clinic during the past 10 years.Methods. Seventeen patients underwent radiosurgery for high-surgical-risk CMs in the following sites: thalamus/basal ganglia (four patients), brainstem (12 patients), and corpus callosum (one patient). All patients had experienced at least two documented hemorrhages before undergoing radiosurgery. Stereotactic magnetic resonance (MR) imaging was used for target localization in all cases. The median margin radiation dose was 18 Gy and the median maximum dose was 32 Gy. The median length of follow-up review following radiosurgery was 51 months.The annual hemorrhage rate during the 51 months preceding radiosurgery was 40.1%, compared with 8.8% in the first 2 years following radiosurgery and 2.9% thereafter. In 10 patients (59%) new neurological deficits developed that were associated with regions of increased signal on long—repetition time MR imaging performed a median of 8 months (range 5–16 months) after radiosurgery. Three patients recovered, giving the group a permanent radiation-related morbidity rate of 41%. Compared with 31 patients harboring arteriovenous malformations (AVMs) of sizes and in locations similar to those of the aforementioned CMs, who underwent radiosurgery during the same time period, the patients with CMs were more likely to experience radiation-related complications (any complication, 59% compared with 10%; p < 0.001; permanent complication, 41% compared with 10%; p = 0.02).Conclusions. It is impossible to conclude that radiosurgery protects patients with CMs against future hemorrhage risk based on the available data, although it appears that some reduction in the bleeding rate occurs after a latency interval of several years. The risk of radiation-related complications after radiosurgery to treat CMs is greater than that found after radiosurgery in AVMs, even when adjusting for lesion size and location and for radiation dose.

A novel dynamic model for experimental spinal cord compression

2005 ◽  
Vol 2 (4) ◽  
pp. 466-471 ◽  
Author(s):  
Gerhard Marquardt ◽  
Matthias Setzer ◽  
Alf Theisen ◽  
Edgar Dettmann ◽  
Volker Seifert
Keyword(s):  
Spinal Cord ◽  
Mr Imaging ◽  
Dynamic Model ◽  
Dura Mater ◽  
Spinal Cord Compression ◽  
Cord Compression ◽  
Neurological Deficits ◽  
Content Type ◽  
Interlaminar Approach ◽  
Fine Print

Object. The goal of this study was to develop a novel dynamic model for experimental spinal cord compression that closely approximates neoplastic epidural compression of the spinal cord in humans. Methods. In 30 New Zealand white rabbits, the thoracic spine was exposed via a posterior approach. On each side of one vertebral lamina a small hole was drilled caudal to the articular process. A silicone band was passed through these holes, forming a loop. The spinal dura mater was exposed via an interlaminar approach. The loop was brought into contact with the dura mater and fixed in its position encircling 270° of the circumference of the spinal cord. Thereafter, the loop was gradually tightened at set times by pulling at the ends of the band and fixing them again in their new position. The spinal cord was thus increasingly compressed in a circular and dynamic manner. Neurological deficits of various degrees were created in all animals in the compression group, and the compressive effect of the loop was reliably demonstrated on MR imaging. After decompression of the spinal cord, the neurological deficits were reversible in the majority of animals, and MR imaging revealed either no signal changes or only circumscribed ones within the cord. In contrast, MR images obtained in animals that did not recover revealed the occurrence of extensive chronic myelopathy. Conclusions. This novel model features reproducibility of paresis and neurological recovery. It is a dynamic model simulating circular tumor growth and is characterized by its easy, straightforward, and cost-saving applicability.

Direct convective delivery of macromolecules to peripheral nerves

1998 ◽  
Vol 89 (4) ◽  
pp. 610-615 ◽  
Author(s):  
Russell R. Lonser ◽  
Robert J. Weil ◽  
Paul F. Morrison ◽  
Lance S. Governale ◽  
Edward H. Oldfield
Keyword(s):  
Mr Imaging ◽  
Peripheral Nerve ◽  
Peripheral Nerves ◽  
Volume Of Distribution ◽  
Neurological Deficits ◽  
Outer Diameter ◽  
Content Type ◽  
Peripheral Nerve Lesions ◽  
New Treatments ◽  
Fine Print

Object. Although many macromolecules have treatment potential for peripheral nerve disease, clinical use of these agents has been restricted because of limitations of delivery including systemic toxicity, heterogeneous dispersion, and inadequate distribution. In an effort to overcome these obstacles, the authors examined the use of convection to deliver and distribute macromolecules into peripheral nerves. Methods. For convective delivery, the authors used a gas-tight, noncompliant system that provided continuous flow through a small silica cannula (inner diameter 100 µm, outer diameter 170 µm) inserted into a peripheral nerve. Increases in the volume of infusion (Vi) (10, 20, 30, 40, and 80 µl) of 14C-labeled (nine nerves) or gadolinium-labeled (two nerves) albumin were infused unilaterally or bilaterally into the tibial nerves of six primates (Macaca mulatta) at 0.5 µl/minute. The volume of distribution (Vd), percentage recovery, and delivery homogeneity were determined using quantitative autoradiography, an imaging program developed by the National Institutes of Health, magnetic resonance (MR) imaging, scintillation counting, and kurtosis (K) analysis. One animal that was infused bilaterally with gadolinium-bound albumin (40 µl to each nerve) underwent MR imaging and was observed for 16 weeks after infusion. The Vd increased with the Vi in a logarithmic fashion. The mean Vd/Vi ratio over all Vi was 3.7 ± 0.8 (mean ± standard deviation). The concentration across the perfused region was homogeneous (K = −1.07). The infusate, which was limited circumferentially by the epineurium, followed the parallel arrangement of axonal fibers and filled long segments of nerve (up to 6.8 cm). Recovery of radioactivity was 75.8 ± 9%. No neurological deficits arose from infusion. Conclusions. Convective delivery of macromolecules to peripheral nerves is safe and reliable. It overcomes obstacles associated with current delivery methods and allows selective regional delivery of putative therapeutic agents to long sections of nerve. This technique should permit the development of new treatments for numerous types of peripheral nerve lesions.

Postoperative swelling of pericranial pedicle graft producing intracranial mass effect

1999 ◽  
Vol 91 (1) ◽  
pp. 124-127 ◽  
Author(s):  
Ric Jensen ◽  
Ian E. McCutcheon ◽  
Franco DeMonte
Keyword(s):  
Skull Base ◽  
Mass Effect ◽  
Frontal Bone ◽  
The Other ◽  
Neurological Deficits ◽  
Content Type ◽  
Intracranial Mass ◽  
Graft Removal ◽  
Postoperative Swelling ◽  
Fine Print

✓ Two cases of florid swelling of pericranial pedicle grafts are reported. Intracranial mass effect produced by the grafts necessitated reoperation with graft removal in one case and graft revision in the other. No permanent neurological deficits were incurred by either patient. Venous congestion and associated swelling within the graft were considered to be related to constriction of the graft base at the frontal bone flap-skull base interface in one patient and torsion of the graft base in the other.

Factors predictive of suboptimal seizure control following selective amygdalohippocampectomy

2002 ◽  
Vol 97 (5) ◽  
pp. 1142-1151 ◽  
Author(s):  
Aviva Abosch ◽  
Neda Bernasconi ◽  
Warren Boling ◽  
Marilyn Jones-Gotman ◽  
Nicole Poulin ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Seizure Control ◽  
Mesial Temporal Lobe Epilepsy ◽  
Class Iii ◽  
Strict Adherence ◽  
Content Type ◽  
Selective Amygdalohippocampectomy ◽  
Postoperative Seizure ◽  
Histopathological Studies ◽  
Fine Print

Object. Selective amygdalohippocampectomy (SelAH) is used in the treatment of mesial temporal lobe epilepsy (MTLE). The goal of this study was to determine factors predictive of poor postoperative seizure control (Engel Class III or IV) following SelAH. Methods. A retrospective study was conducted of 27 patients with poor seizure control postoperatively (Engel III/IV group), in comparison with 27 patients who were free from seizures after surgery (Engel I/II group). The results of electroencephalography, magnetic resonance (MR) imaging, and pathological studies were reviewed, and volumetric MR image analysis was used to compare the extent of the mesial structures that had been resected. In 56% of patients in the Engel III/IV group, significant bitemporal abnormalities were displayed on preoperative EEG studies, compared with 24% of patients in the Engel I/II group (p < 0.05). An analysis of preoperative MR images disclosed five patients (19%) in the Engel III/IV group and no patient in the Engel I/II group with normal hippocampal volumes bilaterally. Thirteen patients in the Engel III/IV group subsequently underwent either extension of the SelAH (six cases) or a corticoamygdalohippocampectomy (seven patients). Three patients from the former and one patient from the latter subgroup subsequently became seizure free (four patients total [34%]). The remaining nine patients did not improve, despite the fact that they had undergone near-total resection of mesial structures. Conclusions. The majority of patients receiving suboptimal seizure control following SelAH did not meet the criteria for unilateral MTLE, based on EEG, MR imaging, and/or histopathological studies. These patients were therefore unlikely to benefit from additional resection of mesial structures. With the benefits of modern imaging, and by strict adherence to selection criteria, SelAH can be predicted to yield excellent postoperative seizure control for nearly all patients with unilateral MTLE. There remains a subpopulation, however, that meets the criteria for MTLE, but does not become free from seizure following SelAH.

Magnetic resonance imaging correlation in pediatric spinal cord injury without radiographic abnormality

2002 ◽  
Vol 97 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Amos O. Dare ◽  
Mark S. Dias ◽  
Veetai Li
Keyword(s):  
Magnetic Resonance Imaging ◽  
Spinal Cord ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Neurological Deficits ◽  
Resonance Imaging ◽  
Content Type ◽  
Cord Injury ◽  
Frankel Grade ◽  
Fine Print

Object. The authors conducted a study to determine correlations between clinical syndromes and early magnetic resonance (MR) imaging—documented findings in children with spinal cord injury without radiographic abnormality (SCIWORA). Methods. The authors retrospectively reviewed the records obtained in 20 patients who presented with SCIWORA to the Children's Hospital of Buffalo between 1992 and 1999. Initial neurological syndromes, subsequent hospital course and outcome, and early MR imaging findings obtained using conventional sequences on a 1.5-tesla unit were recorded. Neurological syndromes on presentation were complete (Frankel Grade A) in two patients (10%), severe partial (Frankel Grade C) in one patient (5%), and mild partial (Frankel Grade D) in 17 patients (85%). Partial neurological deficits resolved in 14 (78%) of 18 patients within 72 hours and lasted more than 72 hours in four patients (22%). Magnetic resonance imaging was performed in both patients presenting with complete injuries and in 17 of 18 patients presenting with partial neurological deficits. The studies were obtained within 24 hours in 17 patients (85%). Neuroimaging revealed spinal cord swelling at the cervical level in one of the children with complete injury and cord edema with associated hemorrhage at cervical and thoracic levels in the other. Neural and extraneural elements were shown to be normal in all 17 patients with partial injuries who underwent MR imaging, including in the four patients with partial motor deficits lasting more than 72 hours. Conclusions. In this series, the predominant neurological presentation of SCIWORA was a mild, partial syndrome that resolved within 72 hours. Magnetic resonance imaging revealed abnormal features only in those patients with complete neurological deficits. These findings suggest that in the acute setting conventional MR imaging sequences may lack the sensitivity to demonstrate neural and extraneural abnormalities associated with partial or temporary neurological deficits of SCIWORA, even when those deficits persist beyond 72 hours.

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