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Biomedical subjects

R M Quencer

Publications and source records attributed to R M Quencer.

At least 145 records · Page 8Linked to original sources
PubMed1976

Jugular venography for evaluation of abnormalities of the skull base.

Jugular venography done to evaluate abnormalities at the base of the skull demonstrated three distinctly different patterns depending on whether there is occlusion, invasion, or growth with in the internal jugular vein. Improper technique results in a lack of intracranial dural sinus filling which may masquerade as venous occlusion. This problem is avoided by adequate neck compression along with proper volume and rate of delivery of contrast. Radiographically, an abnormal jugular vein at the base of the skull will show a concave defect in true occlusion, constriction or invasion of the vein by tumor, or tumor growth within the vein.

Aged↗
PubMedDate not supplied

Gadolinium-enhanced MR in spinal infection.

The purpose of this study was to determine what advantages the use of paramagnetic contrast material might have in evaluating patients clinically suspected of having spinal infection. To determine this we prospectively examined with noncontrast and contrast magnetic resonance (MR) 33 such patients and correlated the MR diagnoses with clinical and pathologic data. Our results showed the following advantages of gadolinium-enhanced MR: it (a) provided excellent anatomical delineation of all epidural abscesses, routinely differentiating them from the adjacent compressed thecal sac even when this was not possible by noncontrast MR; (b) increased observer confidence in the diagnosis of disk space infection and osteomyelitis in patients with equivocal noncontrast MR; (c) localized those portions of paraspinal masses most likely to yield a positive percutaneous biopsy; and (d) identified active infections from those that had responded adequately to antibiotic therapy. We conclude that contrast MR is a valuable adjunct to noncontrast MR when diagnosis, anatomical clarity, and/or lesion activity requires further elucidation.

Abscess↗
PubMedDate not supplied

The value of computed tomography in spinal trauma.

Computed tomography (CT) is recommended for routine use in the evaluation of patients with spinal trauma. An evaluation of the CT scans and complementary radiographic studies of 117 patients with spinal trauma was performed. CT provides critical information often not afforded by conventional radiographs concerning fractures, bullet fragments, surgical devices, and paraspinal pathology. Furthermore, in contrast to myelography, it can demonstrate directly certain soft-tissue abnormalities within the spinal canal, such as intramedullary hematomas, herniated discs, and posttraumatic syrinxes. CT can also determine the etiology of myelographic defects, including those causing total myelographic blocks. Further, aided by intrathecal metrizamide, it can differentiate cord swelling from extrinsic cord pressure and thereby demonstrate the need for medical or surgical therapy.

Adolescent↗
PubMedDate not supplied

The role of intraoperative ultrasonography in the treatment of thoracic and lumbar spine fractures.

The technique of intraoperative ultrasonography is outlined in detail and examples of normal spinal canal anatomy are shown. Twenty-three patients with unstable thoracic and lumbar spine fractures were prospectively treated with Harrington rod reduction and fusion using intraoperative ultrasonography. The pathology at all levels studied corresponded exactly to that seen on preoperative myelograms and computed tomography scans. Intradural pathology also was seen clearly in four patients. This technique makes the use of Harrington rod reduction and posterolateral decompression a possibly safer and more effective method of treating these fractures.

Fracture Fixation, Internal↗
PubMedDate not supplied

Corpus callosotomy for seizures associated with band heterotopia.

Band heterotopia is a severe form of neuronal migration disorder associated with intractable epilepsy and neurologic impairment. Surgical treatment of seizures associated with this malformation has not been reported previously. We report a patient with band heterotopia and poorly controlled atonic seizures causing falls and injury. The patient was treated with anterior corpus callosotomy, with significant postoperative decrease in seizure frequency. Corpus callosotomy is a reasonable alternative to consider in management of patients with cortical heterotopia and intractable seizures.

Adolescent↗
PubMedDate not supplied

Nasopharyngeal angiofibromas: staging and management.

We propose a system for staging nasopharyngeal angiofibromas based on clinical evaluation and computerized tomography. Twenty-three patients with this pathologic diagnosis have been managed at the University of Miami/Jackson Memorial Medical Center in the past two decades. In 13 patients, the clinical diagnosis was confirmed by transnasal biopsy as a minor outpatient procedure. This avoided unnecessary diagnostic studies, shortened the hospital stay, and expedited treatment. Computerized tomography has replaced conventional x-ray studies and routine tomography, although angiography is still necessary for proper evaluation of larger tumors. Stage groupings recommended on the basis of this experience are stage I--tumor confined to nasopharynx; stage II--tumor extending into nasal cavity and/or sphenoid sinus; stage III--tumor extending into one or more of the following: antrum, ethmoid sinus, pterygomaxillary and infratemporal fossae, orbit, and/or cheek; and stage IV--tumor extending into cranial cavity. Surgical excision is recommended for stages I, II, and III. Stage IV tumors require surgical resection and/or radiation therapy with the possible addition of hormonal therapy.

Adolescent↗
PubMedDate not supplied

Intracranial CSF flow in pediatric hydrocephalus: evaluation with cine-MR imaging.

PURPOSE: 1) To describe the pattern of normal intracranial CSF flow in children and 2) to demonstrate altered CSF flow patterns in pediatric hydrocephalus and ventriculomegaly with flow-sensitized cine-MR examinations. METHOD: Cardiac gated, multiframe, gradient echo sequences on a 1.5-T system were displayed on a closed loop cine format and compared to standard MR images. Areas of normal flow and areas of diminished flow were determined. RESULTS: 1) In normal children, the CSF flow follows a consistent pattern with a to-and-fro movement of flow in the aqueduct, foramen of Magendie, and in the dorsal and ventral subarachnoid space at the cervicomedullary junction. 2) In patients with ventricular enlargement, the flow studies showed regional abnormalities of the CSF flow patterns: specifically, lack of flow and hyperdynamic flow. CONCLUSION: Cine-MR for CSF flow evaluation is a useful adjunct to routine MR in the evaluation of pediatric hydrocephalus because it can assist in determining the probable level of CSF obstruction.

Cerebrospinal Fluid↗
PubMedDate not supplied

Chiari III malformation: imaging features.

PURPOSE: To analyze and discuss the MR and CT features of Chiari type III malformations. PATIENTS AND METHOD: MR and CT studies in nine neonates born at term with Chiari type III malformations were retrospectively reviewed. RESULTS: High cervical/low occipital encephaloceles were present in all cases. Hypoplasia of the low and midline aspects of the parietal bones was seen in four patients. The encephaloceles contained varying amounts of brain (cerebellum and occipital lobes, six cases; cerebellum only, three cases), ventricles (fourth, six cases; lateral, three cases), cisterns, and in one case, the medulla and pons. Associated anomalies included: petrous and clivus scalloping (five cases/nine cases), cerebellar hemisphere overgrowth (two cases/nine cases), cerebellar tonsillar herniation (three cases/seven cases), deformed midbrain (nine cases), hydrocephalus (two cases/nine cases), dysgenesis of the corpus callosum (six cases/nine cases), posterior cervical vertebral agenesis (three cases/eight cases), and spinal cord syrinxes (two cases/seven cases). In four patients who underwent surgical resection and closure, aberrant deep draining veins and ectopic venous sinuses within the encephaloceles were found. Pathology examination of the encephalocele (four cases/nine cases) showed multiple anomalies (necrosis, gliosis, heterotopias, meningeal fibrosis) that were not demonstrable by either MR or CT. The marked disorganization of the tissues contained within the cephalocele may account for the lack of MR sensitivity to these abnormalities. CONCLUSION: Preoperative determination of the position of the medulla and pons is essential and is easily accomplished by MR. To avoid surgical complications, the high incidence of venous anomalies should be kept in mind.

Cerebellum↗
PubMedDate not supplied

Sequential cranial MR findings of asymptomatic and neurologically symptomatic HIV+ subjects.

PURPOSE: To compare results of a prospective MR and clinical reevaluation of HIV+ asymptomatic and neurologically symptomatic subjects who had had initially abnormal cranial studies to determine what cranial MR changes occur and how these changes correlate with serial neurologic and neuropsychologic findings. PATIENTS AND METHODS: Thirty-one asymptomatic (n = 20) and neurologically symptomatic (n = 11) subjects seropositive for the human immunodeficiency virus (HIV+) were prospectively reevaluated by cranial magnetic resonance (MR) one to two years following an initially abnormal MR of the brain. RESULTS: All 31 HIV+ subjects with initial abnormal MR had abnormal follow-up scans (showing atrophy and/or white matter lesions). Twenty-seven showed no progression of MR abnormalities (among whom were 18 with minimally abnormal scans who remained asymptomatic with improved or static neuropsychologic performance). Of the four subjects with scan changes (all with clinically suspected HIV encephalopathy), one showed MR, clinical, and neuropsychologic test improvement; the remaining three showed MR (n = 3), neurologic (n = 3), neuropsychologic (n = 1) worsening and autopsy (n = 1) confirmed the presence of HIV-1 containing multinucleated giant cells in the brain. CONCLUSIONS: This study suggests that: 1) Progression of intracranial MR abnormalities due to HIV-1 is seen only in a minority of HIV+ subjects over a 1- to 2-year time period, only in those neurologically symptomatic, and correlates with clinical deterioration. 2) Minor cerebral MR abnormalities seen in HIV+ subjects who remain neurologically asymptomatic do not change over a 1- to 2-year period. 3) Although HIV is known to infect the brain early, it may, nevertheless, not routinely do significant anatomical damage early on in the disease, as based on MR criteria.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

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.

Diagnosis, Differential↗
PubMedDate not supplied

Comparison of gradient-recalled-echo and T2-weighted spin-echo pulse sequences in intramedullary spinal lesions.

Nineteen consecutive patients with spinal intramedullary lesions were studied on a 1.5-T system to compare the quality of T2-weighted spin-echo and gradient-recalled-echo (GRE) pulse sequences. Direct comparisons were made in the sagittal and/or axial planes. Twenty-four studies were performed in the 19 patients. The gradient echoes were usually performed at 300/14 (TR/TE) with a flip angle of 10 degrees. Although no significant diagnostic differences were noted in the sagittal plane, there was a distinct anatomic advantage for GRE imaging over spin-echo imaging in the axial plane. This is believed to be the result of CSF time-of-flight effects in the slice-select direction, which are not compensated for by flow-compensating gradients on the spin-echo images, but which are insignificant in the GRE sequence used in this study. Pathology was seen equally well or better on GRE in 79% (19/24) of the sequences. In the other five cases, the spin-echo image showed a brighter intramedullary signal than that seen on GRE, although GRE showed the lesion in all cases. Our results indicate that properly optimized GRE imaging on a high-field-strength system can replace spin-echo imaging in the spine when intramedullary disease is suspected and that the benefits of GRE are most striking in the axial plane.

Adolescent↗