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R M Quencer

Publications and source records attributed to R M Quencer.

At least 19 recordsLinked to original sources
PubMed1992

Acute traumatic central cord syndrome: MRI-pathological correlations.

The acute traumatic central cord syndrome (ATCCS) is commonly stated to result from an injury which affects primarily the center of the spinal cord and is frequently hemorrhagic. To test the validity of this widely disseminated hypothesis, the magnetic resonance images [MRI] of 11 consecutive cases of ATCCS caused by closed injury to the spine were analyzed and correlated with the gross pathological and histological features of 3 cervical spinal cords obtained at post mortem from patients with ATCCS, including 2 of patients studied by MRI. The MRI studies were performed acutely (18 h to 2 days after injury) in 7 patients and subacutely (3-10 days after injury) in 4. Ten of the 11 patients had pre-existing spondylosis and/or canal stenosis. The 11th suffered a cervical fracture. All patients exhibited hyperintense signal within the parenchyma of the cervical spinal cord on gradient echo MRI. None showed MRI features characteristic of hemorrhage on T1-weighted spin echo or T2-weighted gradient echo studies. Gross and histological examination of the necropsy specimens showed no evidence of blood or blood products within the cord parenchyma: the primary finding was diffuse disruption of axons, especially within the lateral columns of the cervical cord in the region occupied by the corticospinal tracts. The central gray matter was intact. In patients with ATCCS, the predominant loss of motor function in the distal muscles of the upper limbs may reflect the importance of the corticospinal tract for hand and finger function in the primate. In this study, the MRI and pathological observations indicate that ATCCS is predominantly a white matter injury and that intramedullary hemorrhage is not a necessary feature of the syndrome; indeed, it is probably an uncommon event in ATCCS. We suggest that the most common mechanism of injury in ATCCS may be direct compression of the cervical spinal cord by buckling of the ligamenta flava into an already narrowed cervical spinal canal; this would explain the predominance of axonal injury in the white matter of the lateral columns.

Adult↗
PubMed1992

Temporal lobectomy for seizures associated with unilateral schizencephaly.

Schizencephaly is characterized by unilateral or bilateral cerebral clefts associated with neurologic deficits and epilepsy. Most commonly schizencephaly is attributed to abnormal neuronal migration, and these malformations are well visualized by current neuroimaging techniques. This report describes a patient with unilateral schizencephaly and poorly controlled complex partial seizures who was found to have a temporal lobe seizure focus; anterior temporal lobectomy produced nearly complete control of the seizures. Despite the extensive malformation, relatively restricted resection was of significant benefit. The principles of seizure focus localization and resection are applicable to the management of patients with schizencephaly.

Adult↗
PubMed1992

MR imaging of tuberous sclerosis: pathogenesis of this phakomatosis, use of gadopentetate dimeglumine, and literature review.

Findings on cranial magnetic resonance (MR) images were correlated with known histopathologic findings in 42 patients with tuberous sclerosis (TS), 17 of whom received gadopentetate dimeglumine, to extend the range of signs on MR images. Four neuroradiologists recorded the number, sites, configurations, and relative signal intensities of intracranial abnormalities. White matter lesions, found in 39 patients (93%), showed four distinct patterns: (a) straight or curvilinear bands extending radially from the ventricle through the cerebral mantle toward the cortex, (b) wedge-shaped lesions, (c) nonspecific conglomerate foci, and (d) cerebellar radial bands. It is concluded that cortical tubers, white matter lesions, subependymal nodules, and sub-ependymal giant cell astrocytomas (SGCAs) may be enhanced after administration of gadopenetetate dimeglumine. Enhancement of a TS lesion does not indicate neoplastic transformation into SGCA. Imaging surveillance every 12 months appears indicated during the peak ages (8-18 years) of occurrence of SGCA. The appearance of white matter lesions supports the theory that the cerebral lesions of TS may be caused by disordered migration of dysgenetic cells.

Adolescent↗
PubMed1992

Magnetic resonance demonstration of intracranial CSF flow in children.

We determined the feasibility and value of studying intracranial CSF flow in children with potential CSF pathway problems using a cardiac gated cine magnetic resonance (MR) format. We studied 15 consecutive patients with a variety of clinical problems that suggested possible CSF pathway problems. The diagnoses included Chiari malformation, Dandy-Walker syndrome, external hydrocephalus, cerebellar tumor, CNS histoplasmosis, and tuberculous meningitis. In addition to documenting the feasibility of the technique in children (7 of 15 were less than 2 years of age), we derived significant new information relative to pathogenesis and/or therapy. The study provides preliminary evidence supporting intracranial CSF flow studies at the time of routine MR imaging of appropriate children.

Adolescent↗
PubMed1992

Magnetic resonance applications in cerebral injury.

CT and MR imaging are complementary in the evaluation of cerebral head trauma. CT is still more useful for the initial evaluation of the acutely unstable patient who has a head injury. However, many lesions are identified by MR imaging such as cortical contusions, small subdural hematomas, and diffuse axonal injuries that may not be seen on CT examinations. In addition, MR angiography can play an important role in the diagnostic evaluation of the trauma patient. MR angiography can be clinically useful in delineating vascular abnormalities such as arterial occlusions, arteriovenous fistulae, dissecting aneurysms, and venous sinus occlusion. In pediatric trauma, MR imaging appears to be superior to CT in assessing head injuries, particularly those due to child abuse.

Adult↗
PubMed1991

Asymptomatic and neurologically symptomatic HIV-seropositive individuals: prospective evaluation with cranial MR imaging.

As part of a prospective multidisciplinary study of individuals seropositive for the human immunodeficiency virus (HIV), cranial magnetic resonance (MR) imaging was performed on 119 HIV-seropositive subjects (95 asymptomatic, 24 symptomatic) and the results were correlated with clinical data. MR images regarded as positive included those showing atrophy and/or white matter lesions. On the basis of these criteria, 96 subjects had normal MR images and 23 had abnormal images. Results of chi 2 analysis revealed a statistically significant difference between the asymptomatic group (12 of 95 [13%] with abnormal scans) and the symptomatic group (11 of 24 [46%] with abnormal scans) (P = .001). In the asymptomatic group, positive MR images showed fewer, smaller, and/or less extensive abnormalities. The researchers conclude that (a) MR imaging can show indirect evidence of HIV infection early in the disease, but abnormalities will be minor and seen only in a small minority of neurologically asymptomatic subjects; (b) the appearance of clinically recognizable neurologic disease correlates with the MR imaging findings of increasingly severe brain atrophy and white matter lesions; and (c) in some HIV-seropositive subjects, despite neurologic disease, MR images can remain normal. Results indicate that routine screening with cranial MR imaging of neurologically asymptomatic HIV-seropositive individuals would likely result in a low yield of positive findings.

AIDS Dementia Complex↗
PubMed1991

Neuroradiology.

Explore the source record for details and available documents.

Brain Diseases↗
PubMed1991

Meningioangiomatosis: clinical, radiologic, and histopathologic correlation.

Meningioangiomatosis (MA) is a rare, benign, hamartomatous lesion of the leptomeninges; MA has been considered to be a forme fruste of neurofibromatosis. A review of pathology records for patients with MA who were seen between 1970 and 1989 at the authors' institutions revealed four patients (three male and one female; aged 2.5-21.0 years; mean, 10.8 years) with a history of seizures but without the stigmata or family history of neurofibromatosis. Three patients had undergone either computed tomographic (CT) or magnetic resonance (MR) imaging studies. All patients had undergone craniotomies to obtain tissue for pathologic analysis; a peripheral, leptomeningeal lesion was found in all four patients. At CT in two patients, the lesions were most consistent with calcification. At T2-weighted MR imaging in one patient, the lesion demonstrated a hyperintense periphery with associated edema of the white matter. Histopathologic examination demonstrated characteristic features of MA--cortical meningovascular fibroblastic proliferation and leptomeningeal calcification. The accurate diagnosis of MA is important since MA is a benign, surgically correctable cause of seizures.

Adolescent↗
PubMed1991

Complications of epidural anesthesia: MR appearance of abnormalities.

Eight patients with acquired intradural arachnoid abnormalities caused by epidural anesthesia were evaluated with magnetic resonance (MR) imaging (eight patients) and intraoperative ultrasound imaging (four patients). Subarachnoid cysts were found in the lower cervical and thoracic spine in six patients. Irregularity of the surface of the cord was noted in seven cases. Associated intramedullary cysts and myelomalacia were seen in two patients. Arachnoiditis was unsuspected clinically in four patients; findings at MR imaging first suggested the cause of the patients' symptoms. The underlying mechanism for the intradural and cord abnormalities in seven of the eight patients was a chemically induced arachnoiditis produced by the administration of epidural anesthesia; in the eight case, an infection introduced at the time of the epidural injection was the cause of the abnormalities. The authors postulate that the preservative agents in the vials of anesthetic may have been the causative factor of this inflammation in the majority of the cases.

Adult↗
PubMed1990

Cine MR in the evaluation of normal and abnormal CSF flow: intracranial and intraspinal studies.

Evaluation of intracranial and intraspinal CSF flow was accomplished by the use of cardiac gated gradient echo magnetic resonance (MR) technique. Normal patterns of pulsatile flow within the ventricles, cisterns and cervical subarachnoid space were established by this technique and these observations were compared to prior description of CSF flow. With systole there is downward (caudal) flow of CSF in the aqueduct of Sylvius, the foramen of Magendie, the basal cisterns and the dorsal and ventral subarachnoid spaces while during diastole, upward (cranial) flow of CSF in these same structures is seen. The relationships between the cardiac cycle and the CSF pulsations are demonstrated on both magnitude reconstruction and phase reconstruction MR images. Calculations of actual fluid velocity within CSF containing spaces can be obtained from the phase reconstruction images and holds promise for a more accurate analysis of CSF flow. In conditions which result in alterations of flow, cine MR dramatically shows either obstruction or excessively turbulent flow within the CSF pathways. The site of obstructed flow whether in the third ventricle, aqueduct, fourth ventricle, or subarachnoid space can be appreciated by changes in or absence of the normal hypointense signal. Cystic cord lesions such as congenital syringohydromyelia and posttraumatic spinal cord cysts may show pulsatile flow of CSF, a fact which can relate to progressive enlargement of these cysts. The distinction between myelomalacia and cyst formation in the cord is facilitated by the technique. Although the use of cine MR for the analysis of CSF flow is in its infancy, our experience indicates that this technique is useful in a wide range of pathological conditions including, but not limited to, conditions resulting in hydrocephalus or cystic cord lesions.

Brain↗
PubMed1990

Lumbar disk herniation and canal stenosis: value of intraoperative sonography in diagnosis and surgical management.

One hundred four patients with preoperative diagnoses of lumbar canal stenosis, disk herniation, or a combination of both were evaluated with intraoperative sonography with the intent of (1) describing the sonographic characteristics of herniated disks and distinguishing these from bulging anuli, epidural fat, scar tissue, and spondylolisthesis; (2) establishing criteria for adequate decompression of canal stenosis; and (3) determining the usefulness of sonography in monitoring disk removal. Disk material demonstrates medium echogenicity, different in its sonographic features from bone, epidural fat, scar tissue, and epidural veins. A sonographic diagnosis of disk herniation was made in 43 cases, 41 of which were confirmed during surgery. Sonography established the presence or absence of disk herniation (confirmed by surgery) in 14 of 19 patients who had equivocal preoperative findings. After routine diskectomy, residual disk material was found in 17 (41%) of 41 patients, which led to further surgery in 16 patients with removal of the additional disk fragments. In 84 patients undergoing decompressive surgery for canal stenosis, sonography detected residual canal compression in 19 (23%), which led to a widened decompression in 15 of these patients. Sonography can differentiate disk material from other normal or abnormal structures in the canal; therefore, sonographic monitoring helps to ensure adequate bony decompression and complete diskectomy. We conclude that intraoperative sonography is an important tool in the surgical management of lumbar disk disease and stenosis.

Adipose Tissue↗
PubMed1989

A new sign of neurofibromatosis on magnetic resonance imaging of children.

Ten pediatric patients with clinically proved neurofibromatosis underwent magnetic resonance imaging of the brain. Seven of these patients had lesions of increased signal intensity on T2-weighted images in the globus pallidus, brain stem, or cerebellar white matter. The lesions did not correlate with results of the neurologic examination or with developmental status. These abnormalities most likely represent hamartomas and should be recognized as part of the diagnostic spectrum of neurofibromatosis.

Adolescent↗
PubMed1989

MR imaging of intracranial carotid occlusion.

The MR scans of seven patients with intracranial carotid occlusion (five proved, two presumed) were reviewed to evaluate the MR signal characteristics seen in this disorder. Five patients had clinical signs of cerebral infarction. Of the remaining two patients, one was asymptomatic and the other had a long-standing occlusion and headaches. We correlated the MR findings with cerebral angiography in five patients and with CT scans in six patients. All occluded vessels demonstrated MR signal predominantly isointense to brain on proton-density- T1- and T2-weighted images. Since there is an absence of flow, the MR signal is based on the intrinsic properties of the arterial thrombus and possibly on the chronicity of the occlusion. The pathogenesis and histopathology of intravascular thrombus differ significantly from extravascular hematoma, which accounts for the differences in their MR signal characteristics. The demonstration of occluded intracranial vessels may solidify the diagnosis of stroke in cases in which clinical and/or CT findings are equivocal. In patients presenting with infarction, an occluded carotid artery by MR may obviate the need for angiography; however, the demonstration of a patent carotid in conjunction with infarction suggests the possibility of an embolus, which may require angiography. We believe that MR is a valuable adjunct to CT in evaluating patients with cerebrovascular infarction.

Adult↗
PubMed1989

Hemorrhage within pituitary adenomas: how often associated with pituitary apoplexy syndrome?

To determine the clinical significance and specificity of suspected intratumoral hemorrhage in pituitary adenomas, we reviewed the clinical presentations, CT results, and findings at surgery in 12 patients who had hyperintense signal within intrasellar and suprasellar masses on short TR/TE spin-echo MR pulse sequences. Eight of the cases were confirmed at surgery. In seven of the operated cases, hemorrhage was found within pituitary adenomas and in the eight case there was hemorrhage but no identifiable adenomatous tissue. Nine of the 12 patients had CT scans; three had focal areas of increased attenuation, four had focal areas of decreased attenuation, and two had uniform hypoattenuation. All nine of these CT abnormalities correlated with areas of hemorrhage on MR. Three patients had clinical apoplexy; in two there was increased attenuation on CT and in one it was decreased. We found that intratumoral hemorrhage may be seen without clinical evidence of pituitary apoplexy, and that the areas of hemorrhage can appear as low attenuation on CT. CT may be better for visualizing intratumoral hemorrhage within the first few days, but MR is more sensitive in detecting and following the hemorrhage in the subacute stage.

Adenoma↗
PubMed1989

Acquired spinal subarachnoid cysts: evaluation with MR, CT myelography, and intraoperative sonography.

Fifteen patients with acquired spinal subarachnoid cysts (14 surgically proved, one presumed) were evaluated preoperatively with immediate and/or delayed CT myelography (seven patients), MR (11 patients), or both (three patients). CT myelography separated subarachnoid cyst from myelomalacia and/or intramedullary cysts in four cases but failed to diagnose them in three, while MR accurately diagnosed subarachnoid cyst in all 10 cases that were also surgically proved. The results of these preoperative examinations were evaluated to determine the efficacy of each study in diagnosing subarachnoid cysts, ascertaining their extent and internal architecture, and detecting associated abnormalities of the spinal cord. In addition, during surgery these cysts were studied with sonography to gain an understanding of the pathophysiological mechanisms involved in their formation and propagation and to guide the surgeon in their decompression. On the basis of our experience, MR appears to be the most efficient preoperative study in diagnosing and characterizing acquired subarachnoid cyst and associated abnormalities. Intraoperative sonography provides a reliable means of ensuring adequate decompression of these cysts.

Adult↗