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Biomedical subjects

K M Spicer

Publications and source records attributed to K M Spicer.

At least 19 recordsLinked to original sources
PubMed2001

Cholecystokinin-Stimulated mebrofenin (99mTc-Choletec) hepatobiliary scintigraphy in asymptomatic postcholecystectomy individuals: assessment of specificity, interobserver reliability, and reproducibility.

OBJECTIVES: Cholecystokinin-stimulated hepatobiliary scintigraphy (CCK-HBS) is a noninvasive method reported to be highly accurate in the diagnosis of sphincter of Oddi dysfunction. Our primary aim was to assess the specificity of CCK-HBS by evaluating its ability to exclude disease in 20 asymptomatic postcholecystectomy individuals. Secondary aims were to assess the interobserver reliability in scoring the CCK-HBS examinations between three blinded observers and to assess reproducibility of CCK-HBS repeated in the same individuals. METHODS: Twenty asymptomatic postcholecystectomy individuals with normal liver serum chemistries underwent CCK-HBS on two separate occasions. Three nuclear medicine specialists read each CCK-HBS study in a blinded fashion. RESULTS: There was good agreement between the three observers reading the same scans for both the first scan (kappa = 0.554) and the second scan (kappa = 0.507). There was poor agreement between the first and second scans on the same patient, read by the same nuclear medicine specialist (kappa = 0.062-0.385). The overall specificity of the CCK-HBS score was 77.5%; however, the specificity was only 60% when a true negative was defined as two negative CCK-HBS examinations. CONCLUSIONS: Quantitative CCK-HBS is of poor specificity in asymptomatic postcholecystectomy individuals. Hence, it is of questionable value in excluding sphincter of Oddi dysfunction in patients suspected to suffer from this disorder.

Adult↗
PubMed2001

Brain effects of TMS delivered over prefrontal cortex in depressed adults: role of stimulation frequency and coil-cortex distance.

Relative regional brain blood flow was measured in 23 clinically depressed adults by using ECD SPECT at baseline and again during actual prefrontal transcranial magnetic stimulation (TMS) following 5 daily sessions of TMS. TMS over prefrontal cortex caused increased activity in cortex directly under the stimulation (inversely correlated with distance from scalp to cortex) and decreased activity in remote regions (anterior cingulate and anterior temporal poles). High-frequency rTMS (20 Hz) caused more relative flow immediately below the TMS coil than did low-frequency rTMS (5 Hz). Confirming the hypotheses tested, repeated daily TMS over the prefrontal cortex in medication-free depressed adults appears to change both local and remote blood flow in a manner that may also depend on the frequency of stimulation and coil to outer cortex distance.

Adult↗
PubMed2000

Health physics consequences of out-patient treatment of non-Hodgkin's lymphoma with 131I-radiolabeled anti-B1 antibody.

The Medical University of South Carolina is currently participating in clinical trials of 131I radiolabeled Anti-B1 antibody for treatment of Non-Hodgkin's lymphoma. Under current South Carolina Department of Health and Environmental Control regulatory guidelines,; these patients are required to be admitted to the hospital and to remain as inpatients until the whole body burden is <30 mCi or the exposure rate measured 1 m from the patient is <5 mR h(-1). We demonstrate that these patients can be released in accordance with the new recommended guidelines of the Nuclear Regulatory Commission for the release of patients containing radioactive materials in compliance with all radioactive material and public dose standards. This benefits these patients by reducing their risk of infection and other hospital insults and by reducing the length of hospitalizations. Further, unnecessary hospital admissions are decreased, and the overall cost of healthcare delivery for these patients is significantly reduced.

Adult↗
PubMed1999

Teleradiology: technology and practice.

Teleradiology increases the ability of radiologists to provide service to remote and underserved locations as well as coverage at times when direct reading of images is not possible. Good practices for teleradiology are described in the American College of Radiology (ACR) teleradiology standard. Teleradiology equipment is converging with picture archiving and communications systems (PACS) equipment so that diagnostic interpretation from remote locations is possible. Image capture can be directly from digital modalities or by film scanner. Transmission speed is still an issue. High transmission speeds were difficult to achieve but recent improvements may increase speeds and decrease costs.

Costs and Cost Analysis↗
PubMed1999

Changes in prefrontal cortex and paralimbic activity in depression following two weeks of daily left prefrontal TMS.

Twenty-two depressed adults were scanned with perfusion single-photon computed emission tomography before and after 2 weeks of left perfrontal transcranial magnetic stimulation (TMS) in a parallel design, double-blind treatment study. At medication-free baseline, across all subjects, blood flow in the bilateral medial temporal lobes, left prefrontal cortex, and caudate significantly declined with increased depression severity. Also at baseline, depressed adults who responded to TMS, compared with nonresponders, showed increased inferior frontal lobe activity. Following treatment, there was an even greater difference in inferior frontal blood flow in responders compared with nonresponders, and the negative baseline correlations between depression severity and limbic and prefrontal blood flow disappeared. These results suggest that in depressed adults, 10 days of prefrontal TMS affects prefrontal and paralimbic activity, which may explain its antidepressant effects.

Adult↗
PubMed1999

Multiple previous alcohol detoxifications are associated with decreased medial temporal and paralimbic function in the postwithdrawal period.

BACKGROUND: Functional neuroimaging studies after alcohol cessation have demonstrated that chronic alcohol use globally reduces neuronal activity for several weeks. Less is known about the effects of previous alcohol use patterns on regional brain activity. Multiple previous alcohol detoxifications are associated with a worse clinical course and increased risk of seizures, perhaps due to sensitization of key brain structures. We performed the following imaging study in alcoholics in the postwithdrawal period to determine if blood flow in medial temporal structures would differ as a function of previous alcohol use (i.e., whether regions were kindled or sensitized due to multiple detoxifications). METHODS: Fourteen adults meeting DSM-IV criteria for alcohol dependence (mean age 35, 8 SD; 10 men) and participating in a double-blind detoxification medication study underwent a brain perfusion Tc99 m-ECD (Neurolite) single photon emission computed tomography scan on days 7 through 9 (mean 7.6, .5 SD) after their last drink and 2 to 3 days since their last detoxification medication. Seven nonpsychiatrically ill, nonalcohol-dependent healthy adults were scanned as control subjects. RESULTS: Alcoholics compared with controls had widely reduced relative activity in cortical secondary association areas and relatively increased activity in the medial temporal lobes (p < 0.01). Five alcoholic patients with > or = 2 previous detoxifications were compared with five patients in their first detoxification (age and detoxification medication matched). Multiple detoxification patients had significantly lower relative activity in bilateral anterior temporal poles and medial temporal lobes and in visual cortex (p < 0.01) compared with first episode patients. CONCLUSIONS: These studies are consistent with other studies comparing alcoholics and controls. They also suggest that on day 7 of detoxification, alcoholic subjects with multiple previous detoxifications have decreased visual cortex, medial temporal lobes, and anterior paralimbic blood flow, compared with those in their first detoxification. Further studies seem warranted to confirm these initial exploratory results.

Adult↗
PubMed1999

The usefulness of iodine-123 whole-body scans in evaluating thyroid carcinoma and metastases.

OBJECTIVE: It is recognized that diagnostic doses of (131)I larger than 3 mCi will cause some cell injury to the tissue in which it concentrates and reduce subsequent uptake of (131)I administered therapeutically. Iodine-123 has been suggested as an alternate radiopharmaceutical to perform whole-body scans since its primary emissions are photons with minimal particulate radiation and it does not cause thyroid stunning and cell injury. The purpose of this study was to assess the effectiveness of (123)I for whole-body scans. METHODS: We examined 12 patients who had (123)I whole-body scans for known papillary/follicular thyroid cancer and 1 patient with Hurthle cell carcinoma, all with suspected metastases. All patients had undergone neck surgery and were given 0.81-0 mCi (123)I. Twenty-four hours later a whole-body image and static views of relevant areas were obtained. If abnormal uptake was noted, patients were treated with large doses of (131)I and then had whole-body (131)I scans 7-10 d post-therapy. These images were compared to (123)I whole-body scans. RESULTS: All 13 patients had abnormal (123)I scans and were treated with therapeutic doses of (123)I, followed by whole-body scans 7-10 d later. In 11 patients the activity seen on the 123I scans correlated well with that seen on (131)I scans. In 1 patient, additional lesions were noted on the (131)I images. In another patient, neck activity was seen on the (123)I scan but not on the subsequent (131)I post-therapy scan. The (123)I activity was felt to represent esophageal lumen activity. CONCLUSION: We found (123)1 effective in demonstrating residual thyroid tissue, thyroid carcinoma and metastases, and recommend its use for whole-body iodine scans since it does not cause thyroid stunning.

Bone Neoplasms↗
PubMed1997

Ultratag RBC kit for combined cardiac first-pass and multigated acquisition studies.

UNLABELLED: The authors developed a procedure to use the in vitro Ultratag (Mallinckrodt, St. Louis, MO) red blood cell (RBC) labeling kit for both first-pass (FP) and multigated acquisition (MUGA) studies with a high specific activity in a reduced volume (50 mCi/0.5 ml) and a high labeling efficiency that can be used with a single-crystal camera to yield a quality study. METHODS: A packed red blood cell (PRBC) bolus was created by two methods: (a) reducing the volume of the components of the Ultratag kit and (b) centrifuging the final dose volume. The labeling efficiency of each bolus was evaluated, each PRBC bolus was visually inspected for clots and percent hemolysis was assessed using a hemocytometer at 30 min, 1 hr and 2 hr postcentrifugation. RESULTS: Use of the first method, the 50% kit, provided the best results. However, the resulting volume from this kit only approached 1 ml, which is not clinically adequate for a first-pass study. In the second method, the total volume was centrifuged to form a PRBC bolus, which appeared to be stable in the syringe for at least 2 hr. A combined FP/MUGA study from a centrifuged 50% reduced kit was performed in one normal subject as a preliminary assessment of the clinical utility of this procedure. The image quality of the scan is diagnostically adequate. CONCLUSION: By using the in vitro Ultratag kit, a compact PRBC bolus was created that was stable in the syringe and could be reinjected safely into the patient for combined cardiac FP/MUGA studies.

Blood Coagulation↗
PubMed1996

In vivo phosphorus spectroscopy of human skin.

Skin 31P MRS measurements might detect metabolic damage from irradiation, chemotherapy, or ischemia. Although rat and cadaver data have demonstrated this potential (C.D. Cuono, et al., Plast. Reconstr. Surg. 81, 1-11 (1988), H.W. Klein, et al., Ann. Plast. Surg. 20, 547-551 (1988)), few studies of in vivo phosphorus human skin spectra have been published (A. Zemtsov, et al., J. Dermatol. Surg. Oncol. 15, 1207-1211 (1989), A Zemtsov, et al., J. Am. Acad. Dermatol. 30, 959-965 (1994)), and those likely reflect underlying muscle as much as skin. To separate 31P skin and muscle spectra, we have developed a unique two-layer "flotation" phantom for mapping coil sensitivity and an associated semiempirical two-power RF depth-resolved technique. Phantom and method have been applied in a study of 17 normal volunteers to obtain human in vivo 31P skin spectra uncompromised by muscle contamination and to quantitate ratios of major phosphometabolites. Skin results consistently showed low ratios of phosphocreatine (PCr) to adenosine triphosphate (ATP), high levels of phosphomonoester (PME), P(i), and phosphodiester (PDE) relative to PCr, and demonstrated a shift in pH toward greater alkalinity, compared to that with simultaneous muscle results.

Adenosine Triphosphate↗
PubMed1995

Biodistribution and radioimmunopharmacokinetics of 131I-Ama monoclonal antibody in atherosclerotic rabbits.

Monoclonal antibodies have been raised against Ama isolated from human and experimental atherosclerotic plaque. 131I-Ama-MoAb in the whole antibody form was injected into normal NZW rabbits and Watanabe hyperlipidemic rabbits. Biodistribution studies showed that atheromatous aortas had a significantly higher (5-7X) uptake of 131I-Ama-MoAb than that of normal aortas. However, 131I-Ama-MoAb was cleared very slowly from atherosclerotic rabbits. As a result, atheromas could not be identified by imaging because of the low target to non-target ratios.

Animals↗
PubMed1994

Differentiation of adrenal masses with MR imaging: comparison of techniques.

PURPOSE: To determine the efficacy of various magnetic resonance (MR) imaging sequences for the differentiation of adrenal masses. MATERIALS AND METHODS: Fifty-three adrenal masses in 46 patients (adenomas, metastases, myelolipomas, hemorrhages, and pheochromocytomas) were evaluated by means of T1-, T2-, and T2*-weighted sequences, calculated T2 values, chemical shift imaging techniques, and dynamic contrast material-enhanced imaging. The Student t test and receiver operating characteristic analysis were used to evaluate the differences in the groups of masses. RESULTS: Analysis of the chemical shift-induced signal intensity of the adrenal masses and the T2*-weighted sequence enabled differentiation of adenomas, metastases, and pheochromocytomas. Adenomas and pheochromocytomas were also differentiated by means of a heavily T2-weighted sequence. Signal intensity values for all masses overlapped. CONCLUSION: Although a chemical shift imaging technique and a T2*-weighted sequence helped correctly differentiate among the groups of adrenal masses, the degree of overlap suggests that it is still difficult to evaluate disease in individual patients.

Adenoma↗
PubMed1992

Preparation and storage of single-dose portions of exametazime: effects on radiochemical purity after labeling.

The effect of exametazime concentration, storage time, and the volume of the radiolabeling compound on the radiochemical purity of labeled exametazime doses was studied. Exametazime cold unit doses (CUDs) of 0.50, 0.33, 0.25, 0.17, and 0.13 mg/mL were prepared by reconstituting exametazime kits with 0.9% sodium chloride injection. After either one or two days of storage at -10 degrees C, four CUDs of each concentration were labeled with 0.2-0.3 mL of sodium pertechnetate Tc 99m (10-20 mCi). The radiochemical purity of CUDs was evaluated 15 minutes later by instant thin-layer chromatography. In a second experiment, exametazime CUDs of 0.5 mg/mL were prepared. After 0-19 days of storage at -10 degrees C, four CUDs were each labeled with 0.2 mL of sodium pertechnetate Tc 99m (10-20 mCi), and radiochemical purity was measured after 15 minutes. In a third experiment, exametazime CUDs of 0.5 mg/mL were labeled with 2.0 mL of sodium pertechnetate Tc 99m (10-20 mCi) after zero to five days of storage at -10 degrees C. The mean radiochemical purity was unacceptably low (less than 80%) for exametazime CUDs of 0.33, 0.25, 0.17, and 0.13 mg/mL; the 0.5-mg/mL CUDs were acceptably stable. Purity was less than 80% for CUDs stored for more than two days. The radiochemical purity of CUDs labeled with 2.0 mL of sodium pertechnetate Tc 99m was significantly greater than the purity of CUDs labeled with 0.2 mL for storage times exceeding two days.(ABSTRACT TRUNCATED AT 250 WORDS)

Butanones↗
PubMed1991

Effects of a linseed oil enriched diet on endotoxin-induced sequelae: differential in vitro and in vivo effects.

Endotoxin stimulates macrophages to synthesize membrane-associated inflammatory mediators including eicosanoids and procoagulant activity (PCA). Alpha linolenic acid, a component of linseed oil, is metabolized to eicosapentaenoic acid, which may replace arachidonic acid in membrane phospholipids. Thus, ingestion of linseed oil may alter the generation of eicosanoids, PCA and other membrane-dependent responses. This study compared the in vitro endotoxin-induced synthesis of eicosanoids and expression of PCA by peritoneal macrophages obtained from rats fed a control diet and rats fed a diet enriched with linseed oil. The effect of endotoxin on in vivo plasma eicosanoid concentrations, leukogram, and microvascular permeability were determined. Endotoxin (5 ug/ml) stimulated synthesis of iTxB2, i6-keto PGF1 alpha and expression of PCA by macrophages in vitro. These in vitro responses of macrophages from linseed oil fed rats were significantly less than those of macrophages from control rats. In contrast, there were no significant differences in in vivo responses to endotoxin. The fatty acid composition of total lipids and phospholipids in liver and plasma from linseed oil fed rats and control rats were not different. These composite data suggest several possibilities: (1) linseed oil may have effects independent of alpha-linolenic acid on macrophage function, (2) linseed oil may alter the fatty acid composition of macrophage phospholipids prior to changing that of other tissues, and (3) the reduced in vitro responses of peritoneal macrophages may not reflect the systemic responses to endotoxin.

6-Ketoprostaglandin F1 alpha↗
PubMed1990

Preoperative evaluation of cardiac risk using dobutamine-thallium imaging in vascular surgery.

Coronary artery disease is frequently present in patients undergoing evaluation for reconstructive peripheral vascular surgery. Dobutamine-thallium imaging has been shown to be a reliable and sensitive noninvasive method for the detection of significant coronary artery disease. Eighty-seven candidates for vascular reconstruction underwent dobutamine-thallium imaging. Forty-eight patients had an abnormal dobutamine-thallium scan. Twenty-two patients had infarct only, while 26 had reversible ischemia demonstrated on dobutamine-thallium imaging. Fourteen of 26 patients with reversible ischemia underwent cardiac catheterization and 11 showed significant coronary artery disease. Seven patients underwent preoperative coronary bypass grafting or angioplasty. There were no postoperative myocardial events in this group. Three patients were denied surgery on the basis of unreconstructible coronary artery disease, and one patient refused further intervention. Ten patients with reversible myocardial ischemia on dobutamine-thallium imaging underwent vascular surgical reconstruction without coronary revascularization and suffered a 40% incidence of postoperative myocardial ischemic events. Five patients were denied surgery because of presumed significant coronary artery disease on the basis of the dobutamine-thallium imaging and clinical evaluation alone. Thirty-nine patients with normal dobutamine-thallium scans underwent vascular reconstructive surgery with a 5% incidence of postoperative myocardial ischemia. Dobutamine-thallium imaging is a sensitive and reliable screening method which identifies those patients with coronary artery disease who are at high risk for perioperative myocardial ischemia following peripheral vascular surgery.

Aged↗