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Biomedical subjects

P C Davis

Publications and source records attributed to P C Davis.

At least 91 records · Page 5Linked to original sources
PubMed1985

Prolactin-secreting pituitary microadenomas: inaccuracy of high-resolution CT imaging.

Computed tomographic (CT) and surgical findings were correlated retrospectively in 51 patients with preoperative diagnoses of prolactin-secreting pituitary microadenomas. Thirty-nine had microadenomas at surgery. Twenty-three had identifiable discrete lesions. Of these, 21 had microadenomas and two did not; these two groups could not be distinguished reliably. Six patients with proven microadenomas had normal CT scans. Focal hypodense lesions, sellar floor erosion, infundibulum displacement, gland height greater than 8 mm, and an abnormal diaphragma sellae configuration are neither sensitive nor specific findings of microadenoma. A significant number of patients with proven microadenomas had few or none of these abnormalities. Thus, recognition of prolactin microadenoma may not be possible by CT alone, even with high-resolution direct coronal imaging.

Adenoma↗
PubMed1985

Contrast enhancement in CT differentiation between recurrent disk herniation and postoperative scar: prospective study.

Recurrent disk herniation and postoperative scarring are among the major causes of recurrent symptoms after surgery for lumbar disk disease. The myelographic differentiation between these two etiologies is, at best, difficult. To evaluate the role of intravenous contrast enhancement and its impact on making this differentiation using computed tomography (CT), 98 postoperative symptomatic patients were studied prospectively with this technique. Twenty-two patients had subsequent reexploration (23 disk spaces). The unenhanced and enhanced studies of these patients were interpreted independently without surgical information. With contrast enhancement, only three CT studies were considered indeterminate, whereas 10 studies without contrast enhancement were indeterminate. The overall correct diagnosis with contrast enhancement was 17 (74%) of 23, while only 43% of the unenhanced studies yielded the correct diagnosis. Therefore, intravenous contrast enhancement significantly increased the diagnostic accuracy and level of confidence in making the differentiation between recurrent herniated disk and scar.

Cicatrix↗
PubMed1983

Work in progress. Intra-arterial digital subtraction angiography: evaluation in 150 patients.

As part of an ongoing study comparing digital subtraction angiography (DSA) with conventional film-screen angiography, 150 patients were examined with arterial contrast material injections and digital filming techniques alone or combined with conventional angiography. Of 247 injections, the DSA study was good or excellent in 236, approaching the quality of conventional angiography for visualization of vessels greater than 1 mm in size. Advantages included improved vascular detail in selected areas such as the skull base, visualization of minimal contrast concentration in diseased vessels or postoperatively, and imaging of vessels distal to stenoses without the hazards of selective catheterization. DSA permitted rapid positioning under fluoroscopic control, instantaneous viewing of subtracted images, and reduced technologist time and film costs. Contrast material volume was reduced by 40 to 60%, allowing multiple studies in one sitting and study of patients with renal compromise.

Angiography↗
PubMed1975

Cancer of the vagina.

Carcinoma of the vagina may be found in association with carcinoma of the vulva and cervix. Patients with neoplasms in any of these locations should have careful inspection of the entire anogenital tract. As in all malignancies, early diagnosis and prompt, adequate treatment offers the best opportunity for cure.

Adenocarcinoma↗
PubMed1969

Loss of rubella antibody from immune globulin treated with kaolin.

Sera and immune globulin (IG) preparations are customarily treated with kaolin before titration of their rubella hemagglutination-inhibiting (HI) antibody in order to rid them of nonspecific inhibitors of hemagglutination. The treatment was shown in this investigation to have no adverse effect on the antibody level of the sera but was found to remove considerable amounts of gamma-globulin from IG preparations. Evidence of this removal was obtained by serological tests, by spectrophotometric determination of protein concentration and by disc electrophoresis. In contrast to kaolin, heparin-manganese chloride (MnCl(2)) treatment of IG preparations had essentially no effect on the level of antibody globulin by all the criteria used. Heparin-MnCl(2)-treated IG lots were in these respects similar, if not identical, to their untreated counterparts. Since nonspecific inhibitors associated with the beta-lipoprotein fraction of serum are removed by the method employed to fractionate the IG samples, it seems unnecessary to treat the latter in any way for the HI test. No difficulty was encountered in this investigation with several untreated IG lots.

Adsorption↗
PubMedDate not supplied

Neurocognitive functioning and magnetic resonance imaging in children with sickle cell disease.

OBJECTIVE: To examine neurocognitive functioning in children classified with overt cerebral vascular accidents (CVAs), silent infarcts, or without central nervous system (CNS) pathology on magnetic resonance imaging. METHODS: Participants were 63 children and adolescents with sickle cell disease (SCD). RESULTS: Children with overt CVAs and silent infarcts differed from their peers without CNS pathology on measures of attention and executive functioning. CONCLUSIONS: We consider these deficits the result of the high frequency of frontal lobe deficits incurred by children with SCD. Recommendations include the use of tests designed to measure attention and executive functioning as a way of screening children with SCD for possible CNS pathology. We also suggest that future research examine the mechanism underlying frontal lobe involvement for individuals with SCD.

Adolescent↗
PubMedDate not supplied

Social information processing and magnetic resonance imaging in children with sickle cell disease.

OBJECTIVE: To examine social information processing, social skills, and adjustment difficulties in children with sickle cell disease (SCD) as rated by caregivers, teachers, and the children themselves. Children were classified in two groups: cerebral vascular accidents (CVA) (n = 21) or without central nervous system (CNS) pathology (n = 20) on magnetic resonance imaging (MRI). Both groups had HbSS SCD. We compared these two groups and a third group of 11 children who had a milder type of SCD (HbSC). METHODS: Participants referred for evaluation of learning and behavior problems were administered MRIs to ascertain the presence of pathology and a series of measures designed to assess nonverbal emotional decoding abilities and ratings of social emotional functioning. RESULTS: Children with CVA displayed more errors on tasks of facial and vocal emotional decoding than did comparison controls without CVA. CONCLUSIONS: Acquired neurological impairments in children with SCD seemed to be associated with difficulties in the decoding of emotions of other children and adults. We recommend that future research integrate neuropsychological and psychosocial research programs for pediatric chronic illness groups.

Adaptation, Psychological↗
PubMedDate not supplied

Computed tomography of benign masseteric hypertrophy.

Benign masseteric hypertrophy (BMH), although an uncommon condition, is important in the differential diagnosis of parotid region masses. We believe CT is the ideal imaging modality for investigating patients with parotid region masses and that it has proved to be most useful in the diagnosis of masseteric hypertrophy. We present three cases of BMH and describe and discuss the CT findings and differential diagnosis of parotid region masses.

Adult↗
PubMedDate not supplied

Meningioma of the chiasm and optic nerves: CT and MR findings.

A case of meningioma involving the optic nerves, optic chiasm, and optic tracts at presentation is reviewed. Computed tomography showed the chiasm to be engulfed by tumor, and this finding was helpful in differentiating this lesion from an optic chiasm glioma. Magnetic resonance further characterized the lesion by demonstrating the presence of a cystic component along the lateral aspect of the mass.

Cranial Nerve Neoplasms↗
PubMedDate not supplied

Endoscopic paranasal sinus surgery: radiographic evaluation of severe complications.

PURPOSE: To report our experience with the radiographic evaluation of severe complications resulting from the functional endoscopic sinus surgery (FESS) procedure. PATIENTS: Ten major complications were reviewed retrospectively. FINDINGS: Ten major complications occurred. Eight of 10 had injury to the floor of the anterior cranial fossa, fovea ethmoidalis (roof of the ethmoid sinus), or roof of the sphenoid sinus. Six patients presented with meningitis or rhinorrhea, two presented with headache and massive pneumocephalus; one patient who presented with meningitis had a large nasal frontal encephalocele. Noncontrast brain CT that included the paranasal sinuses adequately evaluated the source of pneumocephalus. Thin-section coronal CT accurately predicted the site of leak in five patients. Both coronal sinus CT and MR imaging were useful to confirm the nasal encephalocele. Two of 10 had vascular injury secondary to FESS. One patient presented with subarachnoid hemorrhage seen on noncontrast CT and cerebral angiography demonstrated an aneurysm of the anterior cerebral artery. The second patient suffered severe intraoperative hemorrhage. Emergency angiography revealed a pseudoaneurysm of the cavernous carotid artery, and balloon occlusion of the artery was performed. No deaths occurred in this series. CONCLUSION: Radiologists should be familiar with the rare, but potential complications of this commonly performed procedure in order to help direct the work-up in an efficacious manner.

Adult↗
PubMedDate not supplied

Diagnosis of cerebral metastases: double-dose delayed CT vs contrast-enhanced MR imaging.

For patients suspected of having cerebral metastases, double-dose delayed CT (DDD-CT) has proved significantly more sensitive than CT scans obtained immediately after administration of a lesser dose of iodinated contrast material. Previous reports confirm the advantages of postcontrast MR imaging over contrast-enhanced CT, but data comparing DDD-CT and contrast-enhanced MR have not been reported. This study describes comparative imaging results in 23 patients who had contrast-enhanced MR imaging to clarify equivocal findings on DDD-CT studies. Contrast-enhanced MR demonstrated more than 67 definite or typical parenchymal metastases. T2-weighted MR revealed more than 40, while DDD-CT revealed only 37 typical metastatic lesions. Three patients had five or fewer lesions on DDD-CT and lesions "too numerous to count" on MR. The frequency of equivocal or unconvincing lesions was similar on DDD-CT (11) and contrast-enhanced MR (10). On T2-weighted images, we noted a substantially higher number of equivocal lesions (19), fewer definite metastases, and a number of definite metastases that had no corresponding lesion on the enhanced studies, confirming the inability of T2-weighted imaging to specifically identify cerebral metastases. In one case, multiple tiny lesions on T2-weighted images were not apparent on DDD-CT scans and were recognized only in retrospect on contrast-enhanced MR images. In this series, MR with enhancement proved superior to DDD-CT for lesion detection, anatomic localization of lesions, and differentiation of solitary vs multiple lesions. Cost-benefit considerations precluded a comparison between the two techniques in all patients suspected of having cerebral metastases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Gadopentetate dimeglumine-enhanced MR imaging in children following surgery for brain tumor: spectrum of meningeal findings.

Gadopentetate dimeglumine-enhanced MR imaging was performed in 51 consecutive postoperative pediatric neurosurgical patients with a diagnosis of brain tumor. These studies were examined retrospectively to determine the spectrum of meningeal findings in this patient population. Patterns of enhancement were correlated with type of surgery, interval since surgery, clinical and CSF findings, and the use of radiation and steroid therapies. Normal postoperative meningeal findings include no meningeal enhancement or mild focal or diffuse dural enhancement. More moderate dural or subdural enhancement may be seen in clinically well children who have postsurgical subdural collections, or who have a remote history of serious meningeal disease (meningitis or subarachnoid hemorrhage). In all six cases in which nodular dural, leptomeningeal, or ependymal enhancement was seen, recurrent local tumor, leptomeningeal metastases, or infection were present. Leptomeningeal tumor or infection should be suspected if such patterns of enhancement are noted. Parameters that did not appear to affect the pattern of meningeal enhancement included type of surgery, interval since surgery, or therapeutic radiation.

Adolescent↗