Biomedical subjects

L R Gentry

Publications and source records attributed to L R Gentry.

53 records · Page 3Linked to original sources

PubMed1985

Chymopapain chemonucleolysis: CT changes after treatment.

Chymopapain chemonucleolysis is now used extensively in this country to treat lumbar disk herniation. Despite increasing experience in patient selection, there continue to be patients who do not respond to treatment and require diagnostic reevaluation. Interpretation of postchemonucleolysis computed tomographic (CT) scans in these patients requires a knowledge of the CT changes that normally occur after treatment with chemonucleolysis. To define these temporal changes, a prospective CT evaluation was performed of 29 treated interspaces in 26 patients who returned for routine postchemonucleolysis follow-up. Despite a successful clinical response in 17 of 21 patients, changes in the size, location, shape, homogeneity, and density of the disk herniation were uncommon at the 6 week follow-up. In 24 treated interspaces, the most common changes at 6 week CT follow-up were the development of vacuum phenomenon in three (12.5%) and a slight decrease in the size of two (8.3%) disk herniations. A successful response was noted in 17 of 21 patients scanned at 6 month follow-up, with five (22.7%) of 22 injected interspaces exhibiting vacuum phenomenon and 13 (59.1%) interspaces showing an observable decrease in the size of the disk herniation. Early improvement of sciatica after chemonucleolysis often occurs without a change in the size of the disk herniation and may be mediated by chymopapain-induced disk-space narrowing. Continued improvement may be accompanied by both a decrease in the disk height and a reduction in the size of the disk protrusion.

Adult↗

PubMed1984

Preservation of periosteal attachment in lateral osteotomy.

Cosmetic rhinoplasty with narrowing of the bony vault can potentially reduce the nasal airway. Current surgical methods may aggravate this problem. In an attempt to demonstrate the effect of lateral osteotomy on the resultant airway, 4 cadaver specimens were studied grossly and with CAT scans. It appeared that variations in osteotomy technique did have a demonstrable impact on the size of the nasal airway. An interrupted transperiosteal approach, preserving intervening strands of periosteum, resulted in a more stable nose with less compromise of the airway.

Cadaver↗

PubMed1983

High-resolution CT analysis of facial struts in trauma: 1. Normal anatomy.

The recent availability of high-spatial-resolution thin-section computed tomography (CT), capable of accurately depicting the thin body septa of the facial skeleton, has expanded the role that diagnostic radiology can play in the evaluation of the patient with facial trauma. A detailed knowledge of the normal CT anatomy of the face, however, is essential to optimally utilize this modality. The normal anatomy of the face was investigated in six cadavers using thin-section (1.5 mm) high-resolution CT. A systematic method of analysis that can facilitate evaluation of the face is presented. The face is conceptualized as three groups of interconnected osseous struts or buttresses that are oriented in the horizontal, sagittal, and coronal planes. Each group of struts is closely related to specific soft-tissue structures that are susceptible to injury. Sequential evaluation of each strut and its associated soft tissue assures a comprehensive evaluation of the face. While both axial and coronal sections are of value in some circumstances, the coronal ones are most helpful in accurately depicting the structures of the face that are most likely to be injured in trauma.

Face↗

PubMed1983

High-resolution CT analysis of facial struts in trauma: 2. Osseous and soft-tissue complications.

In six cadavers, high-resolution thin-section computed tomography (CT) was used to evaluate the sequelae of experimentally produced facial trauma. As confirmed by pluridirectional tomography, CT was an effective imaging method for the detection and classification of facial fractures. The ability of CT to simultaneously depict both osseous and soft-tissue structures expands the role that diagnostic radiology can play in the evaluation of the traumatized face. A method of evaluation is presented in which the face is geometrically conceptualized as a series of triplanar (horizontal, sagittal, and coronal) osseous struts. Sequential, systematic assessment of each strut for fracture and its adjacent soft tissue for injury can facilitate evaluation of the traumatized face. Using this approach the osseous and soft-tissue complications arising from experimentally produced trauma are reviewed and illustrated with CT. Examples of potential soft-tissue complications that may occur with fractures of the horizontal group of struts include disruption of the dura matter at the cribiform plate, involvement of the structures of the anterior cranial fossa, injury to the optic nerve, and involvement of the superior and inferior groups of extraocular muscles. Injury to the nasolacrimal duct, maxillary sinus ostium, medial and lateral rectus muscles, or the soft-tissue structures in the superior and inferior orbital fissures may arise from disruption of the sagittal struts. Fractures of the coronal struts may involve the frontal sinus, anterior cranial fossa, lacrimal gland, nasofrontal duct, lacrimal sac, or the soft tissues of the pterygopalatine fossa.

Face↗

PubMed1982

Splenosis: CT demonstration of heterotopic autotransplantation of splenic tissue.

Splenosis is a rare condition manifested by heterotopic autotransplantation of splenic tissue. A case of splenosis initially diagnosed with computed tomography (CT) and confirmed with radionuclide imaging is presented. This condition can be confused with other causes of peritoneal based masses and must be differentiated from them to assure optimum patient care. The clinical, pathologic, and CT features of this condition are briefly reviewed.

Abdominal Neoplasms↗

PubMed1981

Hemorrhagic angiomyolipoma: demonstration by computed tomography.

Preoperative tissue specific diagnosis of renal angiomyolipomas is now frequently made by computed tomography (CT). Although hemorrhage of these hypervascular tumors is a common cause for presentation, it is rarely recognized preoperatively. We present two cases of large, solitary angiomyolipoma complicated by perinephric and intratumoral hemorrhage demonstrated by CT.

Adult↗

PubMedDate not supplied

Bobble-head doll syndrome: review of the pathophysiology and CSF dynamics.

The bobble-head doll syndrome is a rare movement disorder; fewer than 40 cases have been reported. It is usually associated with cystic abnormalities in the region of the anterior third ventricle. Various physiologic mechanisms have been proposed but none of them has been substantiated. We report a patient with this syndrome produced by a suprasellar arachnoid cyst. The CSF dynamics were investigated with CT cisternography. The phenomenon was apparently the result of intermittent obstruction at the foramina of Monro, a feature which has not previously been reported in this condition. The head movement served to partially relieve intraventricular obstruction, by both a posterior displacement of the cyst away from the foramina of Monro and a reduction in cyst size. This finding supports the concept that the bobble-head syndrome may be a "learned" behavior which lessens the symptomatology of hydrocephalus related to foramina of Monro obstruction.

Adolescent↗

PubMedDate not supplied

A double-blind clinical comparison of Hexabrix and Renografin-76 for intravenous digital subtraction angiography.

A double-blind comparison of Hexabrix and Renografin-76 for intravenous digital subtraction angiography (IV-DSA) revealed a slightly greater percentage of patients with good or satisfactory examinations who received Hexabrix. There were fewer perturbations of the ECG, less alteration in the diastolic blood pressure, and no serious adverse reactions noted in the Hexabrix group. However, the differences between the groups were not statistically significant. When used for IV-DSA, the lower osmolality associated with Hexabrix offers the theoretic advantages of (1) reduced osmotic load and (2) diminished alteration in central blood volume.

Adult↗

PubMedDate not supplied

Spontaneous hemorrhage in the medulla oblongata: clinical MR correlations.

A 72-year-old woman with a history of hypertension developed a tegmental medullary syndrome secondary to a spontaneous hemorrhage in the medulla oblongata. A CT examination was diagnostic of the bleeding. However, a magnetic resonance study carried out on the 4th day after the event gave more precise information about the location and extent of the lesion, thus permitting a better correlation with the neurological findings.

Aged↗

PubMedDate not supplied

MR imaging of primary trochlear nerve neoplasms.

We present the clinical, anatomic, and MR imaging findings in six patients with seven primary trochlear nerve neoplasms, as well as the MR and clinical criteria that serve to establish the diagnosis of these rare cranial nerve neoplasms. Three patients had a history of neurofibromatosis and five patients had clinical evidence of a trochlear nerve palsy. Six of seven neoplasms produced localized, fusiform enlargement of the proximal cisternal segments of the trochlear nerves. The lesions that were visible on noncontrast MR scans (T1-, T2-, and proton density-weighted) had signal intensities that were virtually identical to normal brain parenchyma. All lesions showed intense, homogeneous enhancement on contrast-enhanced scans. Contrast-enhanced imaging was necessary for the detection of five of seven lesions and greatly increased the value of the MR study in all six patients.

Adult↗

PubMedDate not supplied

Reduction of the gastrointestinal side effects of metrizamide myelography with oral dexamethasone.

A prospective, double-blind study was undertaken to assess the effectiveness of oral dexamethasone premedication in reducing a variety of side effects associated with metrizamide myelography. We also examined the relationship between side effects and needle size, total metrizamide dose, radiographic findings, and personality. Patients were randomly assigned to either a placebo group (44 patients) or a dexamethasone group (38 patients). All patients completed a 24-item symptom checklist before and 24 hr after lumbar myelography. In addition, all patients completed the Minnesota Multiphasic Personality Inventory prior to myelography. Analysis of variance demonstrated a statistically significant decrease in the frequency of gastrointestinal side effects (loss of appetite, nausea, vomiting) in the dexamethasone group. There were no significant differences between the two groups for the other 21 symptoms examined. We concluded that premedication with oral dexamethasone significantly reduces the gastrointestinal side effects associated with metrizamide myelography. This reduction was especially important in older patients.

Administration, Oral↗

PubMedDate not supplied

High-resolution computed tomography of the basilar artery: 1. Normal size and position.

Normal high-resolution computed tomographic (CT) scans of 126 patients were reviewed to define the diameter, height of the bifurcation, and transverse position of the normal basilar artery. The mean diameter of the normal basilar artery is 3.17 mm at the level of the pons. In 92% of normal subjects, the basilar bifurcation is located in the interpeduncular cistern adjacent to the dorsum sellae or in the suprasellar cistern below the level of the floor of the third ventricle. In 98% of normal individuals, the basilar artery courses in the midline or in a paramedian position, medial to the lateral margins of the clivus and dorsum sellae.

Adolescent↗

PubMedDate not supplied

High-resolution computed tomography of the basilar artery: 2. Vertebrobasilar dolichoectasia: clinical-pathologic correlation and review.

To better define the clinical significance of vertebrobasilar dolichoectasia, the clinical signs and symptoms and basilar artery parameters of diameter, height, and transverse position were evaluated in two groups of symptomatic patients. Ten patients had isolated involvement of the third, sixth, or seventh cranial nerves. The other 10 patients had multiple neurologic deficits including combinations of compressive cranial nerve deficits, both ischemic and compressive central nervous system deficits, and hydrocephalus. Although significant differences for mean basilar artery diameter and height exist between these two groups, the symptomatology and basilar artery parameters present as a spectrum. A symptomatic patient with a normal-caliber, but tortuous, basilar artery is more likely to have isolated cranial nerve involvement. Conversely, the patient with marked basilar artery dilatation (ectasia) is far more likely to present with multiple compressive or ischemic neurologic deficits. Conventional angiography in patients with dilated basilar arteries carries a significant risk for brainstem ischemia. Most authors agree that when vertebrobasilar dolichoectasia has been demonstrated by computed tomography, additional angiography, if required at all, should be performed by digital subtraction techniques.

Adult↗

PubMedDate not supplied

Suprasellar arachnoid cysts: 1. CT recognition.

Suprasellar arachnoid cysts are basal midline masses that represent a rare but surgically remediable cause of hydrocephalus and neurologic deficits. These cysts represent a diagnostic challenge and often go unrecognized for many years. The authors review the computed tomographic (CT) findings in seven patients with documented suprasellar arachnoid cysts and define previously undescribed diagnostic criteria. These cysts usually can be differentiated from cystic midline neoplasms by their CT density, homogeneity, and location as well as by their lack of fat, lack of calcification, and absence of contrast enhancement. Accurate distinction from marked third-ventricular enlargement secondary to obstructive hydrocephalus and from third-ventricular ependymal cysts can be made on the basis of basal cisternal expansion, distinctive mass effect and displacement, the characteristic shape and contour of the apparent "third ventricle," and the appearance of structures at the foramen of Monro. Although metrizamide CT ventriculography and cisternography allow confirmation of the diagnosis and evaluation of cerebrospinal fluid dynamics, these definitive studies will not be obtained unless the cysts are first suspected by their conventional CT appearance.

Adolescent↗

PubMedDate not supplied

Suprasellar arachnoid cysts: 2. Evaluation of CSF dynamics.

Suprasellar arachnoid cysts are an infrequent but surgically remediable cause of hydrocephalus and neurologic deficits. The optimal method of treatment varies according to whether the cyst communicates with the subarachnoid space; the presence or absence of associated hydrocephalus; and the exact site(s) and severity of intraventricular and extraventricular cerebrospinal fluid (CSF) obstruction. Eight patients with suprasellar arachnoid cysts are described to emphasize the importance of pretherapeutic investigation of CSF dynamics. The variability of the ventriculocisternal-cyst CSF dynamics and the value of metrizamide computed tomographic cisternography and ventriculography in investigation of the CSF pathways are stressed. A diagnostic approach to the evaluation of the CSF dynamics is outlined, based on whether hydrocephalic or compressive symptoms predominate.

Adolescent↗

PubMedDate not supplied

Trauma to the corpus callosum: MR features.

The frequency, distribution, and appearance of corpus callosum injuries were evaluated with MR and CT in a prospective study of 78 patients with acute (n = 63) and chronic (n = 15) head injuries. Traumatic lesions of the corpus callosum were detected in 47% of patients. MR was significantly (p less than .001) more sensitive than CT in the detection of callosal injuries. MR and CT visualized 100% and 27%, respectively, of the traumatic callosal lesions that were detected in the study population. The majority of lesions were located in the splenium but a few were also found in the body and genu. Patients with callosal injuries had a significantly higher incidence of primary brainstem injury (p less than .02) as well as a greater number of subcortical gray-matter (p less than .05) and diffuse axonal "shear" (p less than .001) lesions. In addition, patients with callosal injuries had a significantly higher incidence of traumatic lesions of the septum pellucidum (p less than .007) and fornix (p less than .001). Intraventricular hemorrhage occurred significantly more often (p less than .002) in patients with callosal injuries, especially if traumatic lesions of the fornix or septum pellucidum were also present. Patients with callosal injuries had significantly lower initial Glasgow Coma Scale scores (mean, 6.6) than those without injuries (mean, 10.7) (p less than .001). Injury to the corpus callosum occurs much more often with nonfatal head injuries than had been believed previously.

Adolescent↗

PubMedDate not supplied

Clinical comparison of metrizamide and iopamidol for myelography.

A double-blind parallel comparison of iopamidol and metrizamide for myelography was performed in 36 patients. Sixteen adverse reactions were noted in 10 patients who received metrizamide. Six adverse reactions were reported in five patients who received iopamidol. There was no appreciable difference in the radiographic opacification.

Contrast Media↗