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Biomedical subjects

A E Flanders

Publications and source records attributed to A E Flanders.

At least 19 recordsLinked to original sources
PubMed2001

Magnetic resonance imaging analysis of soft tissue disruption after flexion-distraction injuries of the subaxial cervical spine.

STUDY DESIGN: A retrospective study was performed with the use of magnetic resonance imaging to evaluate the type and degree of soft tissue disruption associated with flexion-distraction injuries of the subaxial spine. OBJECTIVE: To determine what soft tissue structures are injured in flexion-distraction injuries of the subaxial spine. SUMMARY OF BACKGROUND DATA: Prior published reports of unilateral and bilateral cervical facet dislocations have described the analyzed mechanisms and biomechanics of this injury subtype. No retrospective magnetic resonance imaging analysis of associated soft tissue disruption has been documented. METHODS: Magnetic resonance imaging evaluations of the cervical spine were obtained for all patients with a flexion-distraction injury, Stages 2 (unilateral facet dislocation) and 3 (bilateral facet dislocation), between September 1994 and May 1998. Two neuroradiologists, blinded to both clinical and radiographic findings, graded all the soft tissue structures for evidence of attenuation or disruption. The soft tissue structures were graded on a scale of 1 (intact), 2 (indeterminate), or 3 (disrupted). RESULTS: For this study, 48 patients satisfied the inclusion criteria: 25 with unilateral facet dislocation and 23 with bilateral facet dislocation. Disruption to the posterior musculature, interspinous ligament, supraspinous ligament, facet capsule, ligamentum flavum, and posterior and anterior longitudinal ligaments was found in a statistically significant number of patients with bilateral facet dislocation. For most of these structures, disruption was found to be statistically significant in patients with a unilateral facet dislocation, except for the posterior longitudinal ligament, in which significance was not consistently demonstrated using 95% confidence intervals in the binomial testing. In a comparison between unilateral and bilateral facet dislocations using a two-sided Fisher's exact test, it was found that disruption to the anterior and posterior longitudinal ligaments and the left facet capsule were statistically significant, with all three more prominent in bilateral facet dislocation. A multivariate analysis between unilateral and bilateral facet dislocations showed that disruption to the anterior longitudinal ligament was associated significantly with a bilateral facet dislocation. Disc disruption was found to be associated significantly with both injury types, but was more common in bilateral facet dislocation, although this difference in intergroup comparisons was not statistically significant. CONCLUSIONS: Unilateral and bilateral facet dislocations of the subaxial spine are associated with damage to numerous soft tissue structures that provide stability to the lower cervical spine. Damage to the posterior longitudinal ligament did not occur consistently in unilateral facet dislocations. Bilateral facet dislocations were associated significantly with disruption to the posterior and anterior longitudinal ligaments and left facet capsule, as compared with unilateral facet dislocations. Magnetic resonance imaging allows visualization of these disruptions.

Cervical Vertebrae↗
PubMed2001

Results of a pilot study involving the use of an antisense oligodeoxynucleotide directed against the insulin-like growth factor type I receptor in malignant astrocytomas.

PURPOSE: Preclinical animal experiments support the use of an antisense oligodeoxynucleotide directed against the insulin-like growth factor type I receptor (IGF-IR/AS ODN) as an effective potential antitumor agent. We performed a human pilot safety and feasibility study using an IGF-IR/AS ODN strategy in patients with malignant astrocytoma. PATIENTS AND METHODS: Autologous glioma cells collected at surgery were treated ex vivo with an IGF-IR/AS ODN, encapsulated in diffusion chambers, reimplanted in the rectus sheath within 24 hours of craniotomy, and retrieved after a 24-hour in situ incubation. Serial posttreatment assessments included clinical examination, laboratory studies, and magnetic resonance imaging scans. RESULTS: Other than deep venous thrombosis noted in some patients, no other treatment-related side effects were observed. IGF-IR/AS ODN-treated cells, when retrieved and assessed, were < or = 2% intact by trypan blue exclusion, and none of the intact cells were viable in culture thereafter. Parallel Western blots disclosed IGF-IR downregulation to < or = 10% after ex vivo antisense treatment. At follow-up, clinical and radiographic improvements were observed in eight of 12 patients, including three cases of distal recurrence with unexpected spontaneous or postsurgical regression at either the primary or the distant intracranial site. CONCLUSION: Ex vivo IGF-IR/AS ODN treatment of autologous glioma cells induces apoptosis and a host response in vivo without unusual side effects. Subsequent transient and sustained radiographic and clinical improvements warrant further clinical investigations.

Adult↗
PubMed2001

Functional MR imaging of the human cervical spinal cord.

BACKGROUND AND PURPOSE: Although research with functional MR imaging of the brain has proliferated over the past 5 years, technical limitations, such as motion, chemical shift, and susceptibility artifacts, have impeded such research in the human spinal cord. The purpose of this investigation was to determine whether a reliable functional MR imaging signal can be elicited from the cervical spinal cord during simple motor activity. METHODS: Subjects performed three different motor tasks that activate different segments of the spinal cord. Gradient-echo-planar imaging on a 1.5-T clinical unit was used to image cervical spinal cords of human subjects. Another group of subjects was imaged while performing isometric exercise to study the relationship between the blood oxygenation level-dependent (BOLD) signal and applied force. RESULTS: Task-dependent BOLD activity was detected in all subjects. Signal amplitude varied between 0.5% and 7%. Moreover, a linear relationship was found between the applied force and the signal amplitude during isometric exercise. While regions of activation were distributed throughout the spinal cord, concentrated activity was found in the anatomic locations of expected motor innervation. CONCLUSION: The functional MR imaging signal can be reliably detected with motor activity in the human cervical spinal cord on a 1.5-T clinical unit. The location of neural activation has an anatomic correspondence to the myotome in use. The strength of the BOLD signal is directly proportional to the level of muscular activity.

Cervical Vertebrae↗
PubMed1999

Magnetic resonance evaluation of the intervertebral disc, spinal ligaments, and spinal cord before and after closed traction reduction of cervical spine dislocations.

STUDY DESIGN: A prospective clinical study using magnetic resonance imaging of the cervical spine in a consecutive series of patients with cervical spine dislocations. OBJECTIVES: To determine the incidence of intervertebral disc herniations and injury to the spinal ligaments before and after awake closed traction reduction of cervical spine dislocations. SUMMARY OF BACKGROUND DATA: Prior series in which the prereduction imaging of disc herniations in the dislocated cervical spine are described have been anecdotal and have involved small numbers of patients. In addition, no uniform clinical criteria to define the presence of an intervertebral disc herniation in the dislocated cervical spine has been described. The incidence of disc herniations in the unreduced dislocated cervical spine is unknown. METHODS: Eleven consecutive patients with cervical spine dislocations who met the clinical criteria for an awake closed traction reduction had prereduction and postreduction magnetic resonance imaging. Using strict clinical criteria for the definition of an intervertebral disc herniation, the presence or absence of disc herniation, spinal ligament injury, and cord injury was determined. Neurologic status before, during, and after the closed reduction maneuver was documented. RESULTS: Disc herniations were identified in 2 of 11 patients before reduction. Awake closed traction reduction was successful in 9 of the 11 patients. Of the nine patients with a successful closed reduction, two had disc herniations before reduction, and five had disc herniations after reduction. No patient had neurologic worsening after attempted awake closed traction reduction. CONCLUSIONS: The process of closed traction reduction appears to increase the incidence of intervertebral disc herniations. The relation of these findings, however, to the neurologic safety of awake closed traction reduction remain unclear.

Adolescent↗
PubMed1999

Optic gliomas.

Primary tumors of the optic nerve are uncommon. The most common are optic nerve gliomas (ONGs), which account for 66% of all primary optic nerve tumors. Seventy-five percent of gliomas are diagnosed in the first decade of life, and 90% are diagnosed in the first two decades. This article discusses the anatomy and imaging of the optic pathway and the clinical manifestations of ONGs.

Adult↗
PubMed1999

Imaging of sellar and parasellar pathology.

This article reviews the complex anatomic relationships between structures in the sellar and parasellar regions. Normal anatomy and the normal imaging spectrum are reviewed, with emphasis on the diversity of pathology that originates from this region. Both CT and MR imaging may be used to evaluate the sellar and parasellar regions. This article discusses how modern imaging techniques enable characterization of the many lesions that alter the structure and function of normal sellar and parasellar anatomy.

Diagnostic Imaging↗
PubMed1999

Stereotactic radiosurgical pallidotomy and thalamotomy with the gamma knife: MR imaging findings with clinical correlation--preliminary experience.

PURPOSE: To evaluate the temporal evolution and appearance of a radiosurgical lesion at magnetic resonance (MR) imaging and the clinical response in patients undergoing stereotactic radiosurgical pallidotomy or thalamotomy with the gamma knife. MATERIALS AND METHODS: Seventeen patients with medically refractory movement disorders underwent stereotactic radiosurgical pallidotomy (n = 2) or thalamotomy (n = 15). A single dose of 120-140 Gy was administered to a target in the globus pallidus interna or ventralis intermedius thalamic nucleus. Postprocedure gadolinium-enhanced MR imaging and clinical assessment were performed at 1 month and 3 months. RESULTS: At 3 months, the radiosurgical lesion most commonly (n = 11) appeared as a ring-enhancing focus 5 mm or less in diameter surrounded by vasogenic edema that extended less than 7 mm in radius beyond the target. Five patients had ring-enhancing lesions 7 mm or more in diameter; four of these developed symptomatic perilesional edema at 3 (n = 2) or 8 (n = 2) months after the procedure. Onset of therapeutic effect began approximately 4 weeks after treatment. In the 15 patients with tremor, there was a mean decline of 2.1 on the Tremor Rating Scale. CONCLUSION: Findings in this pilot study suggest that radiosurgical thalamotomy is a promising treatment for medically refractory tremor. Three-month follow-up MR studies show a ring-enhancing lesion surrounded by a variable amount of vasogenic edema. Visualization of the radiosurgical lesion and the clinical response are delayed compared to that with radio-frequency procedures.

Adult↗
PubMed1999

The relationship between the functional abilities of patients with cervical spinal cord injury and the severity of damage revealed by MR imaging.

BACKGROUND AND PURPOSE: The appearance of the damaged spinal cord after injury correlates with initial neurologic deficit, as determined by the American Spinal Injury Association grade and manual muscle test score, as well as with recovery, as assessed by manual muscle test scores. The purpose of this study was to determine whether the presence of spinal cord hemorrhage and the size and location of spinal cord edema on MR images is predictive of functional recovery in survivors of cervical spinal cord injury (SCI). METHODS: The degree of damage to the cervical spinal cord was measured on the MR images of 49 patients who underwent imaging within 72 hours of sustaining SCI. The effects of hemorrhage and length/location of edema on changes in the value of the motor scale of the functional independence measure (FIM) were assessed on admission to and discharge from rehabilitation. RESULTS: Patients without spinal cord hemorrhage had significant improvement in self-care and mobility scores compared with patients with hemorrhage. There was no significant effect of spinal cord hemorrhage on changes in locomotion and sphincter control scores. The rostral limit of edema positively correlated with admission and discharge self-care scores and with admission mobility and locomotion scores. Edema length had a negative correlation with all FIM scales at admission and discharge. CONCLUSION: The imaging characteristics of cervical SCI (hemorrhage and edema) are related to levels of physical recovery as determined by the FIM scale. Imaging factors that correlate with poor functional recovery are hemorrhage, long segments of edema, and high cervical locations.

Activities of Daily Living↗
PubMed1998

Long-term evaluation of vertebral artery injuries following cervical spine trauma using magnetic resonance angiography.

STUDY DESIGN: A prospective study to determine the long-term outcome of traumatically induced vertebral artery injuries. Magnetic resonance angiography was performed at the time of cervical injury and at a follow-up office visit. OBJECTIVE: To determine the long-term outcome in terms of arterial flow competency of traumatically induced vertebral artery injuries. SUMMARY OF BACKGROUND DATA: Vertebral artery injury associated with cervical spine trauma has been well documented; however its healing or nonhealing potential has not been elucidated. METHODS: During the 7-month period from July 1993 to January 1994, all patients admitted to the authors' institution with cervical spine injuries underwent magnetic resonance imaging and magnetic resonance angiography of the cervical spine to determine the patency of their vertebral arteries. Magnetic resonance angiography was performed at the time of injury and at a follow-up office visit. Twelve of 61 patients were found to have a lack of signal flow within one of their vertebral vessels during this study period. RESULTS: Eighty-three percent of the patients (five of six) who were available for follow-up observation in this study did not manifest flow reconstitution of their vertebral arteries after an average 25.8-month follow-up period. CONCLUSIONS: According to these data, most patients with vertebral artery injuries after nonpenetrating cervical spine trauma do not reconstitute flow in the injured vertebral arteries. This lack of flow must be considered if future surgery in this region of the cervical spine is contemplated.

Adult↗
PubMed1997

Treatable lumbosacral polyradiculitis masquerading as diabetic amyotrophy.

Patients with diabetic amyotrophy may have an inflammatory vasculopathy and may obtain reversal of neurological deficits with immunosuppression. We present a patient with NIDDM, subacute onset of painful asymmetric polyradiculopathy, and unilateral enhancement of lumbar nerve roots on MRI. Clinical improvement and resolution of nerve root enhancement occurred with immunosuppression. We suggest, therefore, that nerve biopsy and gadolinum-enhanced lumbosacral MRI be performed in all patients presenting with diabetic amyotrophy. If nerve root enhancement is present or if nerve biopsy shows perivascular infiltrates, we recommend a trial of immunosuppression.

Anti-Inflammatory Agents↗
PubMed1997

Enhanced MR imaging of hypertrophic pachymeningitis.

OBJECTIVE: This report illustrates the contrast enhancement characteristics on MR imaging of three patients with hypertrophic pachymeningitis and provides an explanation for the observed imaging findings. CONCLUSION: A differential pattern of enhancement, consisting of intense enhancement of the peripheral margin of the abnormal pachymeninges, was present in all cases. In two patients, much of the remaining abnormal pachymeninges did not enhance at all. On the basis of the microscopic pathology of hypertrophic pachymeningitis, the physiology of normal meningeal enhancement on MR imaging, and the described MR appearance of other pachymeningeal lesions, this differential pattern of enhancement should strongly suggest the diagnosis of hypertrophic pachymeningitis.

Adult↗
PubMed1996

MRI of orbital hydroxyapatite implants.

Our aim was to use MRI for the postsurgical assessment of a new form of integrated orbital implant composed of a porous calcium phosphate hydroxyapatite substrate. We studied ten patients 24-74 years of age who underwent enucleation and implantation of a hydroxyapatite ball; 5-13 months after surgery, each patient was examined by spinecho MRI, with fat suppression and gadolinium enhancement. Fibrovascular ingrowth was demonstrated in all ten patients as areas of enhancement at the periphery of the hydroxyapatite sphere that extended to the center to a variable degree. The radiologist should aware of the MRI appearances of the coralline hydroxyapatite orbital implant since it is now widely used following enucleation. MRI is a useful means to determine successful incorporation of the substrate into the orbital tissues. The normal pattern of contrast enhancement should not be mistaken for recurrent tumor or infection.

Adult↗
PubMed1996

MRI and angiographic diagnosis of lupus cerebral vasculitis.

The authors present a patient with striking angiographic findings of systemic lupus erythematosus (SLE) cerebral vasculitis. Although lupus is often cited as part of the differential diagnosis for angiographically apparent cerebral vasculitis, true SLE cerebral vasculitis is rare in pathological and radiological series. The clinical spectrum and pathological findings of CNS lupus with particular attention to cerebral vasculitis are briefly discussed.

Arteritis↗
PubMed1996

Carotid magnetic resonance angiography: improved image quality with dual 3-inch surface coils.

Magnetic resonance angiography (MRA) hs inherent artifacts due to variation in velocity and direction of flowing blood in the carotid bulb and regions of stenosis. We examined the efficiency of dual 3-inch surface coils to delineate carotid artery flow better. Carotid MRA was performed on ten healthy volunteers and six patients, on a 1.5 T system. A special adapter was constructed to use with 3-inch (receive-only) coils, which were placed over the carotid bifurcations. Routine anterior neck coils were also used. Contiguous axial two-dimensional (45/8.7, 1.5 mm, flip angle 60 degrees) time-of-flight sequences were used. Image matrix was 256 x 256 with two signals averaged and acquisition time 6-10 min. These images were postprocessed and reformatted into angiographic views using a maximum intensity projection algorithm. Computer simulation of carotid artery blood flow throughout the cardiac cycle based on vessel contours derived from digital subtraction angiography was carried out by finite element analysis. Improved definition of vessel margin, particularly at the carotid bifurcation, and substantially increased signal-to-background ratio of flowing blood were obtained with 3-in-chcoils. Apparent loss of signal in the carotid bulb was diminished. In one patient, contiguous flow throughout a high-grade stenosis was well defined, with the surface coil method, while drop-off of signal was observed with routine neck coil imaging.

Adult↗
PubMed1996

The role of magnetic resonance imaging in children with intraocular tumors and simulating lesions.

PURPOSE: To evaluate the role of pre- and post-contrast magnetic resonance (MR) studies in children with intraocular tumors and simulating lesions. METHODS: Patients younger than 12 years of age with the diagnosis of an intraocular tumor or simulating lesion with a thickness greater than 2.0 mm underwent pre- and post-contrast MR studies with surface coil. All post-contrast-enhanced images were performed with fat suppression techniques. RESULTS: There were 40 children with the clinical diagnosis of an intraocular lesion as follows: retinoblastoma (n = 22), Coats disease (n = 5), ciliary body medulloepithelioma (n = 2), primary hyperplastic persistent vitreous (PHPV) (n = 2), retinal capillary hemangioma (n = 3), massive retinal gliosis (phthisis bulbi) (n = 2), uveal melanoma (n = 1), ciliary body leiomyoma (n = 1), retinopathy of prematurity (ROP) with total retinal detachment (n = 1), and post-traumatic retinal gliosis (n = 1). In the authors' series, solid intraocular tumors greater than 2.0 mm in thickness such as retinoblastoma, ciliary body medulloepithelioma, leiomyoma, choroidal melanoma, and retinal capillary hemangioma appeared hyperintense on T1-weighted images and hypointense on T2-weighted images. Secondary serous or exudative retinal detachment, regardless of the underlying etiology (neoplasm, Coats disease, PHPV, phthisis bulbi, ROP), showed hyperintensity of the subretinal space on both T1- and T2-weighted images. Retinal gliosis was hypointense on both T1- and T2-weighted images. On contrast-enhanced T1-weighted images with fat suppression techniques, minimal to marked enhancement was observed in retinoblastoma, medulloepithelioma, retinal capillary hemangioma, leiomyoma, and choroidal melanoma. No enhancement was demonstrated in the subretinal space of Coats disease, PHPV, ROP, and in retinal gliosis. Calcification was identified in 54% of retinoblastoma tumors on MR sequences. Calcification showed low signal intensity on both T1- and T2-weighted images, with lack of enhancement on contrast-enhanced sequences, thus differentiating it from surrounding tumor or tissue necrosis. The associated serous or exudative subretinal fluid secondary to intraocular tumors or simulating lesions did not demonstrate enhancement after contrast administration, therefore differentiating it from the causative lesion. CONCLUSION: Pre- and post-contrast MR studies allowed differentiation of solid intraocular tumors such as retinoblastoma, medulloepithelioma, retinal capillary hemangioma, leiomyoma, and choroidal melanoma from intraocular lesions with primary retinal detachment such as Coats disease, PHPV, massive retinal gliosis (phthisis bulbi), ROP, and associated subretinal fluid or hemorrhage. Heterogeneity within retinoblastoma suggests foci of tumor necrosis and/or calcification. The various solid intraocular tumors were not reliably differentiated from one another based on MR features.

Child↗