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Biomedical subjects

W P Dillon

Publications and source records attributed to W P Dillon.

At least 19 recordsLinked to original sources
PubMed1992

Advances in diagnostic techniques of pituitary tumors and prolactinomas.

The main advances in the diagnostic evaluation of pituitary tumors and prolactinomas have been in the areas of improved magnetic resonance techniques and in the use of inferior petrosal sinus sampling. New dynamic techniques of rapid acquisition magnetic resonance imaging during bolus contrast infusion have improved the sensitivity for the diagnosis of the small microadenoma. The development of three-dimensional volume imaging has also led to a further improvement in sensitivity to small lesions of the sella. The measurement of adrenocorticotropin levels in the inferior petrosal sinus in patients with Cushing's syndrome assists in the differentiation of adrenocorticotropin-secreting pituitary tumor from other peripheral causes of the syndrome. The use of corticotropin-releasing hormone concomitant with sampling has proven to be of value in improving sensitivity and specificity. Elevated levels of growth hormone in petrosal sinus sampling have also been shown to be valuable in the early diagnosis of acromegaly when peripheral hormone levels and imaging are nondiagnostic.

Adenoma↗
PubMed1992

Lesions of the foramen ovale: CT-guided fine-needle aspiration.

To verify perineural spread of tumor along the mandibular division of the trigeminal nerve in four patients, the authors obtained cytologic specimens by means of a CT-guided transfacial fine-needle aspiration technique. Diagnoses were squamous cell carcinoma (n = 3) and meningioma (n = 1). The technique allows biopsy of deep lesions that would otherwise require open surgical biopsy.

Biopsy, Needle↗
PubMed1992

Alterations in brain phosphorus metabolite concentrations associated with areas of high signal intensity in white matter at MR imaging.

Areas of high signal intensity in white matter are identified on brain magnetic resonance (MR) imaging studies in 25%-50% of elderly subjects. The authors used phosphorus-31 MR spectroscopy to characterize the metabolic status of hemispheric white matter brain volumes in 30 elderly subjects with white matter areas of high signal intensity at MR imaging. Compared with white matter volumes with no or minimal areas of high intensity, white matter volumes with extensive areas of high intensity evidenced a 26% decrease in the adenosine triphosphate (ATP)/inorganic phosphate (Pi) ratio (P = .03) and a 21% decrease in the ATP concentration (P = .05), with the Pi level unchanged. A pilot P-31 spectroscopic imaging study in a subject with a large, coalescing white matter area of high signal intensity demonstrated large reductions in metabolite concentrations in the high-signal-intensity area. These results suggest that extensive white matter areas of high signal intensity indicate a process that affects white matter cellular energy metabolism.

Adenosine Triphosphate↗
PubMed1992

Obstetric care and cesarean birth rates: a program to monitor quality of care.

OBJECTIVE: To study the quality of obstetric care in relation to rising cesarean rates, a Task Force was formed in New York state by the Department of Health and ACOG District II. The Task Force also included the Organization of Obstetric, Gynecologic, and Neonatal Nurses and the Hospital Association of New York State. The goals were to enhance hospitals' in-house review processes, standardize terminology, and improve the quality of care. A premise of the program was that if quality of care improved, cesarean rates would fall. METHODS: A Dictionary of Terms was developed to standardize clinical and diagnostic terminology. A two-tiered review process was instituted, using internal and external hospital reviews. A format for in-house review of obstetric care was developed and recommended to hospitals. External reviews were conducted at 24 hospitals during 1989-1990. Review teams, composed of obstetrician-gynecologists and obstetric nurses in active obstetric practice, assessed obstetric facilities, staffing, medical care, and the in-house review process. Contacts continued with the hospitals after site visits to follow up on implementation of recommendations. General recommendations to improve care, based on the overall program experience, were distributed to hospitals and physicians as part of educational efforts to improve quality of care. RESULTS: The state cesarean rate reversed. Statistics for 1989 and 1990 showed a stronger downward trend in reviewed hospitals than in non-reviewed hospitals. A survey of reviewed hospitals reported a positive response to the review process. CONCLUSION: A successful quality assurance program can be jointly developed by a state regulatory agency and a medical specialty society.

Cesarean Section↗
PubMed1992

Intractable complex partial seizure: correlation of magnetic resonance imaging with pathology and electroencephalography.

We prospectively analyzed MR studies of 32 patients with intractable complex partial seizures, who later underwent resection of EEG-proven seizure foci. Twenty-seven patients were imaged at 1.5, 4 at 0.35, and 1 at 0.5 Tesla. Correlation was obtained on all patients with EEG and surgical pathology. Of 19 patients with mesial temporal sclerosis (MTS), 13 exhibited an MR abnormality at the site of pathology as determined by EEG and surgery. Abnormalities included increased (8) or decreased (1) signal intensity, distortion of gray-white interface (1) and temporal lobe atrophy (3). Six patients had no abnormalities at the site of the diseased focus. MR was more sensitive in patients with other structural lesions which included tumor, encephalitis, polymicrogyria, cryptic vascular malformation, and tuberous sclerosis. Prior studies indicate some usefulness of MR in intractable seizure patients, but many report relative insensitivity of MR in defining an abnormality (as low as 11%). Our results demonstrate the usefulness of high-resolution thin-section multiplanar MR using cardiac gating or flow compensation techniques in this patient population.

Atrophy↗
PubMed1992

Neuroradiology of the immunosuppressed state.

In recent years, one of the most common reasons for neuroimaging has become the evaluation of the immunosuppressed patient. In this review the radiographic appearances of the common inflammatory and neoplastic conditions affecting the central nervous system in patients with HIV infection, as well as the AIDS-dementia complex, are discussed. Non-AIDS immunocompromised neurologic disease is also examined, with particular emphasis on the effect of various immunosuppressive medications on the brain and spine.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Unilateral hydrocephalus in adults.

The authors report 14 cases of unilateral hydrocephalus in adults. Headache was the most common presenting symptom. Unilateral hydrocephalus was documented in each patient with computed tomography scans; magnetic resonance imaging was also used in seven patients in the latter part of the series. Unilateral hydrocephalus was caused by tumor (seven patients), venous angioma (one patient), ependymal cyst (one patient), postinflammatory gliosis (one patient), and was idiopathic in four patients. The primary surgical treatment was craniotomy with fenestration of the septum pellucidum, which relieved symptoms in eight of nine patients for whom long-term follow-up data were available.

Adolescent↗
PubMed1991

Orbit, skull base, and pharynx: contrast-enhanced fat suppression MR imaging.

The high signal intensity of fat on T1-weighted magnetic resonance images has limited the utility of gadopentetate dimeglumine in imaging of the extracranial head and neck. Enhancing lesions may be obscured either by proximity to fat or by chemical misregistration artifact. The authors evaluated the role of a gadolinium-enhanced fat suppression imaging technique in the detection of extracranial head and neck abnormalities in 29 patients. These studies were directly compared with conventional pre- and postcontrast T1- and T2-weighted SE sequences. In detecting and defining the extent of abnormalities, fat-suppressed images were superior to non-fat-suppressed gadolinium-enhanced T1-weighted images in the majority of cases (22 of 27 [81%]). Fat-suppressed images were particularly beneficial in the detection of perineural spread of tumor as well as in defining lesions situated within or adjacent to fat-containing areas such as the base of the skull. These findings demonstrate that fat suppression techniques in combination with gadolinium enhancement are of value in extracranial head and neck imaging and should replace conventional postcontrast T1-weighted SE imaging.

Adipose Tissue↗
PubMed1991

Hemangioma of the nasal vault: MR and CT features.

Six patients with a history of epistaxis (five patients) or nasal obstruction (one patient) were found to have a capillary hemangioma of the nasal vault that involved one or more nasal turbinates. Four patients underwent computed tomographic (CT) examination; two of these also underwent magnetic resonance (MR) imaging. Four others underwent only MR imaging. At CT and MR, all of the lesions were well circumscribed and intensely enhancing, with contralateral deviation of the nasal septum. Remodeling of the surrounding bone was present in three patients. On T1-weighted MR images, the masses were intermediate in signal intensity. Varying degrees of T2 shortening were shown on T2-weighted MR images, with an appearance that suggested the presence of blood products surrounding an inner matrix of higher-signal-intensity tumor. Intense enhancement at CT and MR assisted differentiation of tumor from retained sinonasal secretions. In two patients, external carotid arteriography revealed small foci of pooling contrast material; in one of these patients, arteriovenous shunting was also present. Pathologic examination in all patients demonstrated capillary hemangiomas with varying degrees of fibrosis and hemosiderin deposition.

Adult↗
PubMed1991

Clinical safety and efficacy of gadoteridol: a study in 411 patients with suspected intracranial and spinal disease.

In this phase III study, 411 adult patients with suspected intracranial or spinal disease underwent magnetic resonance (MR) imaging before and after intravenous injection of 0.1 mmol/kg gadoteridol (gadolinium 1,4,7-tris [carboxymethyl]-10-[2'-hydroxypropyl]-1,4,7,10-tetraazacyclododecane+ ++). MR images were evaluated by a single unblinded reader at each of 27 sites; the diagnosis was confirmed with one of nine imaging or surgical procedures within 8 weeks before or after MR imaging. After injection, no clinically significant changes were noted in laboratory values, physical examination, or vital signs. Adverse clinical events possibly or probably associated with injection of gadoteridol were seen in 18 of 411 patients (4.4%); the most common were dysgeusia and mild nausea, and all abated without residual effects. MR images enhanced with gadoteridol in patients with confirmed disease provided more diagnostic information than unenhanced images in 128 of 175 brain examinations (73.1%) and 93 of 137 spinal examinations (67.9%). A change in diagnosis because of additional information from contrast-enhanced images was considered likely in 63 of 214 cranial and 54 of 161 spinal studies.

Adult↗
PubMed1991

Magnetic resonance imaging of vertebrobasilar ectasia in tic convulsif. Case report.

A patient with trigeminal neuralgia and hemifacial spasm was evaluated using multiplanar magnetic resonance (MR) imaging with gadolinium enhancement. Preoperative images demonstrated massively ectatic vertebral and basilar arteries and their distortion of the brain stem and the trigeminal and facial nerves. Surgical manipulation included selective trigeminal rhizotomy, cushioning of the residual nerve at the point of maximal distortion by the underlying basilar artery, and microvascular decompression of the seventh nerve from the anterior inferior cerebellar artery which was being pushed dorsomedially by the vertebral artery. Postoperatively, the patient had neither trigeminal neuralgia nor facial spasm. Gadolinium-enhanced MR imaging not only excludes other etiologies such as tumor or arteriovenous malformation, but also demonstrates cranial nerve compression by ectatic vertebral and basilar arteries. The choice of preoperative imaging modality is discussed and the literature concerning the etiology of tic convulsif is reviewed.

Basilar Artery↗
PubMed1991

The impact of radiologic imaging on staging of cancer of the head and neck.

CT and MRI are both useful for assessing deep tissue extensions of squamous cell carcinomas of the extracranial head and neck region that are stage T2 or greater. Diagnostic imaging information, in combination with clinical findings, will establish the stage of a primary tumor and the status of regional nodes and will allow a rational treatment plan to be made. Once treatment is completed, a baseline scan 3 to 6 months following treatment is recommended in patients who are at risk for a later recurrence. For most primary tumor sites, MRI will give the most information concerning recurrent disease. Occult primary tumors with regional node metastases present a special set of circumstances. CT or MRI scans are recommended prior to performing random biopsies to search for elusive primary tumors in the upper aerodigestive tract.

Carcinoma, Squamous Cell↗
PubMed1991

Imaging of central nervous system tumors.

Magnetic resonance imaging has been used increasingly in the staging and evaluation of neoplasia of the brain and leptomeninges. In the classification of gliomas, the MR accuracy rate approaches that of pathologic diagnosis. Contrast-enhanced MR imaging has improved specificity in evaluating brain tumors in children and is now the preferred modality for evaluating leptomeningeal metastases of the brain and spine. MR imaging in children has also increased the specificity of histologic diagnosis in hypothalamic hamartoma and juvenile pilocytic astrocytoma. Gadolinium enhancement is most useful in patients older than 35 years of age who have focal neurologic complaints and certain disease histories. The expense of gadolinium contrast material is the major drawback to its routine use. In patients with seizure disorder, MR imaging is more sensitive than CT for detecting abnormalities such as mesial temporal sclerosis, tumors, and vascular malformations. Gadolinium enhancement may be useful in differentiating tumors from mesial temporal sclerosis. Recent reports on the use of MR spectroscopy for evaluating brain metabolism and tumors demonstrate that differences in metabolites exist. A correlation was found in epidermoid tumors between high signal on T1-weighted images and high lipid content, and several studies have shown a positive correlation between glioma grade and glycolytic activity as determined on 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography.

Brain Neoplasms↗
PubMed1991

Imaging of the neck.

The neck encloses a tremendous spectrum of tissues in a compact space. The normal and pathologic anatomy of the neck can be exquisitely displayed with high-resolution CT and MR imaging. Accurate assessment of the neck requires a thorough knowledge of both its complex anatomy and the scope of pathologic entities that may affect the various cervical compartments. We review the advances in the past year that serve to improve our ability to identify and characterize pathology of the cervical soft tissues.

Diagnostic Imaging↗