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L M Fig

Publications and source records attributed to L M Fig.

At least 37 records · Page 2Linked to original sources
PubMed1990

Utility of emission tomography in evaluation of mandibular bone grafts.

Bone scanning, performed within 1 week postoperatively, is valuable in predicting the survival of revascularized composite flap grafts. Conventional planar scintigraphy is limited by a two-dimensional representation of three-dimensional structures. Single photon emission computed tomography (SPECT) is a technique in which a gamma camera rotates around the patient, acquires multiple projections, and with the aid of a computer, reconstructs three-dimensional representations. We wished to evaluate the potential advantages of SPECT in the assessment of mandibular graft viability and to compare it with planar scanning. These noninvasive methods of assessing the vascular supply are critical to patient management in the early postoperative period because the presence of or inability to exclude vascular compromise commands surgical exploration of the anastomosis for graft salvage. Fifteen patients who underwent mandibular reconstruction with revascularized free grafts were studied by both planar and SPECT scintigraphy. Long-term follow-up data were correlated with the outcome predicted by the scanning.

Adult↗
PubMed1990

Morphine-augmented hepatobiliary scintigraphy in the severely ill: caution is in order.

Morphine augmentation in hepatobiliary scintigraphy has been reported as a useful tool to shorten imaging time. The technique has not been extensively evaluated in patients who are severely ill and receiving total parenteral nutrition, although the study of these patients with non-morphine-augmented hepatobiliary scintigraphy is problematic. The authors retrospectively analyzed 51 morphine-augmented hepatobiliary studies performed in a tertiary referral center on a population with a high proportion of severe intercurrent illness (18 patients, 14 of whom were receiving total parenteral nutrition) and hepatocellular dysfunction (eight patients). The overall sensitivity was 94%, specificity was 69%, and the false-positive rate was 40% for the diagnosis of acute cholecystitis. The majority of the false-positive cases occurred in the severely ill subgroup (false-positive rate, 60%). Morphine-augmented hepatobiliary studies may be advantageous because of shortened imaging time. However, patients who have severe intercurrent illness, whether or not they are receiving total parenteral nutrition, have a higher frequency of false-positive morphine-augmented hepatobiliary studies, and positive findings at scintigraphy in this patient group should be interpreted with caution.

Acute Disease↗
PubMed1989

Echocardiographic confirmation of mitral valve prolapse: a new finding on radionuclide ventriculography--a case report.

A prominent filling defect was depicted on a radionuclide ventriculogram in a patient with mitral regurgitation. This defect was later shown, by cardiac ultrasound, to be due to mitral valve prolapse into the left ventricle during diastole. This case illustrates that mitral valve prolapse should be added to the list of clinical entities that can result in an intraventricular defect on a radionuclide ventriculogram.

Adult↗
PubMed1989

Radiochemical diagnosis of adrenal disease.

The adrenal gland consists of cortical and medullary components, both of which may be functionally imaged using radiopharmaceuticals designed to take advantage of the specialized physiology of each tissue. Radiolabeled cholesterol derivatives are taken up by normal and abnormal adrenal cortex and provide an in vitro map of adrenocortical function in Cushing's Syndrome, hyperaldosteronism, and hyperadrenogenism. Quantification of uptake shows strong correlation with biochemical parameters of adrenocortical hyperfunction. In the case of incidentally discovered euadrenal masses scintigraphy may help to distinguish between benign, nonfunctional cortical adenomas, and destructive, potentially malignant lesions. Radiolabeled metaiodobenzylguanidine (MIBG) is a tracer of type I uptake and intracellular storage capacity for catecholamines in sympathomedullary tissues and tumors derived from this system. This permits the location of pheochromocytomas of all types (benign and malignant, intra- and extra-adrenal, sporadic and familial) as well as neuroblastomas in all stages. Other neuroendocrine tumors with type I uptake capacity may also be imaged. In suitable cases preliminary data suggests the administration of large doses of MIBG may permit internal radiotherapy of otherwise untreatable neuroendocrine tumors.

Adrenal Gland Diseases↗
PubMed1989

Unusual complications of antithyroid drug therapy: four case reports and review of literature.

Two cases of propylthiouracil-associated acute hepatitis, one case of fatal methimazole-associated hepatocellular necrosis and one case of propylthiouracil-associated lupus-like syndrome are described. The literature related to antithyroid drug side effects and the mechanisms for their occurrence are reviewed and the efficacy and complications of thyroidectomy and radioiodine compared to those of antithyroid drugs. It is concluded that in most circumstances 131I is the therapy of choice for hyperthyroidism.

Adult↗
PubMed1989

Management of pheochromocytoma.

The fundamental principles of pheochromocytoma management are reviewed. These are a high index of clinical suspicion; biochemical confirmation of the diagnosis; preoperative localization and pharmacologic treatment with alpha-adrenergic blockers (and occasionally with beta-adrenergic blockers and/or alpha-methylparatyrosine); meticulous anesthesia and intraoperative cardiovascular monitoring; and attention to the surgical principles of wide exposure, careful dissection and complete exploration, early interruption of tumor vasculature, and delivery of the tumor with the capsule intact. For malignant lesions, the roles of pharmacologic management (alpha- and beta-adrenergic blockade, alpha-methylparatyrosine, and drugs for heart failure, diabetes, and pain), teleradiotherapy, radiopharmaceutical treatment with I-131 MIBG and chemotherapy (with cyclophosphamide, vincristine, and dacarbazine) are discussed.

Adrenal Gland Neoplasms↗
PubMed1989

Clinical features, diagnosis, and localization of carcinoid tumors and their management.

In this article, we have focused on the evolving face of neuroendocrine tumors, newer approaches to their diagnosis and localization, the importance of sophisticated immunohistochemistry, tracer scanning, and the role of peptide therapy in the management of the symptom complex as well as the tumor. With recent expansion in our understanding of the pathophysiology of these tumors have come new and innovative approaches to their management. There is, however, much that remains unsolved and that requires diligent research and evaluation if we are ultimately to include neuroendocrine tumors among the curable cancers.

Carcinoid Tumor↗
PubMed1989

Labetalol reduces iodine-131 MIBG uptake by pheochromocytoma and normal tissues.

Iodine-131 metaiodobenzylguanidine [131I]MIBG has proven to be an effective radiopharmaceutical for the scintigraphic localization of pheochromocytomas. Uptake of MIBG is inhibited by blockade of the neuronal uptake pathway for catecholamines ("uptake-1") and by depletion of catecholamine storage vesicle contents, but is not significantly affected by conventional alpha- and beta-adrenoreceptor blocking drugs. Labetalol is an antihypertensive agent with combined alpha- and beta-blocking properties that has been used to manage patients with suspected pheochromocytomas. We report eight patients in whom concurrent or recent therapy with labetalol significantly reduced the uptake of [131I]MIBG into salivary glands, liver, spleen, and general body background. Tumor uptake of MIBG was also reduced in two of the three patients who were proven to have pheochromocytomas. In one case, the effect of labetalol persisted for 36 hr after the drug had been discontinued. The inhibitory effect of labetalol on MIBG uptake in sympathomedullary tissues is likely to be a result of the drug's little-known, additional properties of uptake-1 blockade and depletion of storage vesicle contents, rather than its alpha- or beta-blocking effects. Additionally, labetalol would also appear to hasten clearance of MIBG from other tissues. Labetalol therapy should be discontinued for several days (possibly up to 1 wk) before undertaking [131I]MIBG scintigraphy. A comprehensive list of drugs that should be avoided in patients undergoing MIBG scintigraphy is appended.

3-Iodobenzylguanidine↗
PubMed1989

Alterations of iodine-131 MIBG biodistribution in an anephric patient: comparison to normal and impaired renal function.

Iodine-131 metaiodobenzylguanidine (MIBG) is an effective agent for the scintigraphic portrayal of pheochromocytomas of all types. Iodine-131 MIBG is a relatively stable radiopharmaceutical that is primarily excreted in the urine. Therefore, impaired renal function would be expected to alter [131I]MIBG pharmacokinetics which would thus affect blood levels, as well as scintigraphy. An 18-yr-old anephric male presented with hypertension and suspected pheochromocytoma. We have compared the [131I]MIBG scintigraphy and blood clearance kinetics in this anephric patient, two patients with renal insufficiency and four patients with normal renal function. The degree of renal insufficiency was directly correlated to the CPM/image (an index of whole-body retention) on all 3 days of imaging and the slower clearance of radioactivity from the blood. The relative distribution of radioactivity between the plasma and cell fractions was greatest in the patients with renal insufficiency. We therefore suggest that attention be paid to plasma creatinine levels prior to the administration of [131I] MIBG to permit accurate interpretation of scintigraphy. In addition, the effect of renal insufficiency on radiation dosimetry should be considered. It may thus be prudent to reduce the administered dose of [131I]MIBG given to anephric or renally insufficient patients to decrease radiation dose.

3-Iodobenzylguanidine↗
PubMed1988

Adrenal localization in the adrenocorticotropic hormone-independent Cushing syndrome.

STUDY OBJECTIVE: To assess the efficacy of 131I-6-beta-iodomethylnorcholesterol scintigraphy in the adrenocorticotropic hormone-independent Cushing syndrome and to compare this with computed tomography. DESIGN: Retrospective analysis of case series from 1977 to 1987. SETTING: Referral to the Division of Nuclear Medicine at a tertiary-care university medical center. PATIENTS: Twenty-four patients with a pathologically-confirmed diagnosis of the adrenocorticotropic hormone-independent Cushing syndrome had 131I-6-beta-iodomethylnorcholesterol scintigraphy and, in most cases, computed tomography. MEASUREMENTS AND MAIN RESULTS: Using 131I-6-beta-iodomethylnorcholesterol scintigraphy, adenomas were accurately seen as focal, unilateral tracer uptake in 14 of 14 patients. In carcinoma, the classic scintigraphic pattern of bilateral nonvisualization was observed in 3 of 4 patients, with ipsilateral uptake of tracer in 1 patient with a histologically well-differentiated malignancy. Computed tomography done during the same interval depicted abnormal adrenals in all cases of adenoma and carcinoma. In cortical nodular hyperplasia, however, computed tomography identified abnormal pairs of adrenals in only one of four cases studied, whereas scintigraphy showed typical patterns of bilateral increased uptake in all of the cases. CONCLUSION: 131I-6-beta-iodomethylnorcholesterol scintigraphy accurately shows the location and nature of adrenal dysfunction in the adrenocorticotropic hormone-independent Cushing syndrome and may be particularly useful in identifying the bilateral adrenal involvement in cortical nodular hyperplasia.

19-Iodocholesterol↗
PubMed1988

Scintigraphic detection of sinusitis.

Radionuclide scintigraphy is useful in the diagnosis of sinusitis. Three cases are described, using different radionuclide agents (99mTc-MDP, 67Ga-citrate and 111In-leukocytes) in which sinusitis was discovered, though clinically unsuspected. The advantages and limitations of these agents are briefly reviewed.

Adolescent↗
PubMed1987

Exercise-induced hyperphagia in the hamster is associated with elevated plasma somatostatin-like immunoreactivity.

Syrian golden hamsters when allowed free access to food and an exercise wheel will run long distances and develop hyperphagia and accelerated linear body growth with high circulating levels of growth hormone and insulin. Somatostatin, a widely distributed brain-gut neurohormonal peptide, modulates nutrient absorption and may regulate food intake. To examine the role of circulating plasma somatostatin-like immunoreactivity (SRIF-LI; pg/ml) in exercise induced hyperphagia 4 groups of animals were studied; an unrestricted exercise group (279.0 +/- 107.7, n = 10); a sedentary group (121.1 +/- 40.8, n = 8); a restricted exercise group (107.7 +/- 12.4, n = 6); and a restricted no exercise group (115.5 +/- 45.9, n = 9). Thus, the unrestricted exercise group has a significantly elevated SRIF-LI concentration (P less than 0.01) while there was no difference between the other 3 groups. The elevation of plasma SRIF-LI in the unrestricted exercise group may represent a response to modulate increased nutrient entry in this group or may represent an incompletely effective satiety signal.

Animals↗
PubMedDate not supplied

Alteration of corticothalamic perfusion ratios during a PTSD flashback.

We performed a single photon emission computed tomography (SPECT) study of patients with posttraumatic stress disorder (PTSD) by measuring changes in regional cerebral blood flow (rCBF) during provocation by combat stimuli. A single patient experienced an actual flashback following exposure to combat sounds, exhibiting tearfulness, diaphoresis, tachypnea, and severe agitation. Results from his SPECT study demonstrated a dramatically altered ratio of cortical to subcortical perfusion during the flashback but not during the control scan. This altered pattern, which showed a peak of activity in the thalamus, was not consistent with global rCBF changes induced by hyperventilation. The perfusion pattern during the patient's control scan was qualitatively indistinguishable from any of the SPECT scans obtained for the other patients. This single case suggests a possible role for corticothalamic dysfunction in flashbacks.

Acoustic Stimulation↗
PubMedDate not supplied

Medial frontal cortex involvement in PTSD symptoms: a SPECT study.

The regional cerebral blood flow (rCBF) responses to a combat stress-related auditory stimulus was examined in Vietnam veterans diagnosed with posttraumatic stress disorder (PTSD). Based on prior data in healthy subjects, we hypothesized that the medial prefrontal cortex may be involved in the processing of stress responses. Twelve male veterans diagnosed with PTSD, 11 age-matched, combat-exposed subjects without PTSD, and 12 healthy control subjects were studied with single-photon emission tomography and the blood flow tracer [99mTc]-HMPAO. Subjects were studied twice, while listening to combat sounds or white noise. Significant increases in the blood flow to the medial prefrontal cortex were observed in PTSD patients, but not in the control groups, which correlated at trend levels with psychophysical measures of stress response. These data support the involvement of the medial prefrontal cortex in the pathophysiology of PTSD, possibly mediating some of its symptoms.

Acoustic Stimulation↗