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21.
Attenuation correction in myocardial perfusion SPECT/CT: effects of misregistration and value of reregistration. 总被引:2,自引:0,他引:2
Sibyll Goetze Tracy L Brown William C Lavely Zhe Zhang Frank M Bengel 《Journal of nuclear medicine》2007,48(7):1090-1095
The accuracy of myocardial perfusion SPECT improves with attenuation correction. Algorithms for attenuation correction in hybrid SPECT/CT systems have the potential for misregistration of emission and transmission scans because CT and SPECT are obtained sequentially. Misregistration will influence regional tracer distribution and may reduce diagnostic accuracy. This study focused on the role of misregistration in cardiac SPECT/CT and the performance of a software-based approach for reregistration. METHODS: We included 105 consecutive patients who underwent clinical myocardial perfusion imaging on a SPECT/CT system. Images were quantitatively assessed for misregistration using fusion software. Results were recorded in millimeters in the x-, y-, and z-axes. Regional tracer uptake in 6 segments (anterior, septal, inferior, lateral, anteroapical, and inferoapical) for noncorrected and attenuation-corrected images before and after reregistration was obtained from polar maps. To determine the relative influence of misregistration, we correlated individual differences between noncorrected and attenuation-corrected images, as well as between attenuation-corrected images before and after reregistration, with the degree of misregistration in a multivariate analysis including additional clinical variables such as sex and body weight. RESULTS: The difference in regional radiotracer uptake was significant between noncorrected and attenuation-corrected images in all 6 segments and was most pronounced in the inferior wall. On multivariate analysis, misregistration contributed significantly to changes in radiotracer distribution in the anterior (P = 0.038), septal (P = 0.011), and inferior (P = 0.006) segments. The mean misregistration was 8.6 +/- 3.8 mm (1.25 +/- 0.55 pixel). Misregistration of one or more pixels was observed in 64% of studies. Reregistration of misalignment significantly affected regional radiotracer distribution in the segments shown to be influenced by misregistration. CONCLUSION: Misregistration occurs with SPECT/CT systems and influences regional tracer distribution on attenuation-corrected myocardial images. Reregistration of misaligned studies may be a useful tool for correction. The impact of this strategy on the diagnostic and prognostic accuracy of cardiac hybrid imaging needs to be determined. 相似文献
22.
Taking advantage of two large, population-based, and longitudinal datasets collected after the 1999 floods in Mexico (n = 561) and the September 11, 2001 terrorist attacks in New York (n = 1267), we examined the notion that resilience may be best understood and measured as one member of a set of trajectories that may follow exposure to trauma or severe stress. We hypothesized that resistance, resilience, recovery, relapsing/remitting, delayed dysfunction, and chronic dysfunction trajectories were all possible in the aftermath of major disasters. Semi-parametric group-based modeling yielded the strongest evidence for resistance (no or mild and stable symptoms), resilience (initially moderate or severe symptoms followed by a sharp decrease), recovery (initially moderate or severe symptoms followed by a gradual decrease), and chronic dysfunction (moderate or severe and stable symptoms), as these trajectories were prevalent in both samples. Neither Mexico nor New York showed a relapsing/remitting trajectory, and only New York showed a delayed dysfunction trajectory. Understanding patterns of psychological distress over time may present opportunities for interventions that aim to increase resilience, and decrease more adverse trajectories, after mass traumatic events. 相似文献
23.
H. A. Tillmann Hein MD C. Tracy Suit MD Linda K. Douning MD Samuel P. Marynick MD J. Michael Putman MD Lily Zhang PhD Michael A.E. Ramsey MD 《Journal of clinical anesthesia》1997,9(8):617
This study retrospectively compares patients who underwent outpatient transvaginal follicle aspiration with either a propofol- or methohexital-based intravenous sedation technique. Data collected from patient charts (n = 212) over a 46-month period were analyzed to determine the effects of each sedation technique on procedure and recovery times, number of retrieved ova, as well as rates of nausea, fertilization, cleavage, pregnancy, and delivery. All patients were included in the study, regardless of age or diagnosis. procedure time was lower in the propofol group (51 t 18 min) than in the methohexital group (61 I 20 min) (p > 0.01). Patients in the methohexital group (139 2 51 min) spent more time in the recovery room than did those in the propofol group (71 ? 34 min) (p > 0.01). The nausea rates were significantly lower in the propofol group compared with the methohexital group (1.9% vs. 14.4%, respectively) (p > 0.02). Fertilization rate in the propofol group was 77.7% and was 62.9% in the methohexital group (p > 0.01). The numbers of retrieved ova and the cleavage rates were similar in both groups. The rate of pregnancy in patients sedated with propofol (46.1%) was higher than the methohexital group (26.9%) (p > 0.02). Delivery rate was 38.5% in the propofol group and 20.6% in the methohexital group (p > 0.02). In summary, propofol intravenous sedation for transvaginal follicle aspiration was associ- ated with an improved outcome. Pregnancy and delivery rates were higher while nausea, an unpleasant side effect, was sharply reduced. 相似文献
24.
Resistance exercise training and alendronate reverse glucocorticoid-induced osteoporosis in heart transplant recipients. 总被引:1,自引:0,他引:1
Randy W Braith Peter M Magyari Michael N Fulton Juan Aranda Tracy Walker James A Hill 《The Journal of heart and lung transplantation》2003,22(10):1082-1090
BACKGROUND: Immunosuppression therapy with bolus glucocorticoids causes regional osteoporosis in the axial skeleton of heart transplant recipients (HTR). No preventive strategy is generally accepted for steroid-induced bone loss. METHODS: To determine the efficacy of an anti-osteoporosis regimen that combined a bisphosphonate agent (alendronate sodium) with the osteogenic stimulus of mechanical loading, 25 HTRs were randomly assigned either to a group that received alendronate (10 mg/day) for 6 months (ALEN; n = 8), a group that received alendronate (10 mg/day) and performed specific resistance exercises for 6 months (ALEN + TRN; n = 8) or to a non-intervention control group (CONTR; n = 9). Alendronate was initiated at 2 months after transplantation. Bone mineral density (BMD) of the total body, femur neck and lumbar spine (L-2 and L-3) was measured by dual-energy X-ray absorptiometry before and 2, 5 and 8 months after transplantation. Resistance training consisted of lumbar extension exercise (MedX) performed 1 day/week and 8 variable resistance exercises (MedX) performed 2 days/week. RESULTS: Pre-transplantation BMD values did not differ among the 3 groups. BMD of the total body, femur neck and lumbar vertebra were significantly decreased below baseline at 2 months after transplantation in CONTR (-2.6 +/- 0.9%, -5.1 +/- 1.8%, -12.5 +/- 4.2%, respectively), ALEN (-2.8 +/- 0.8%, -5.3 +/- 1.6%, -12.0 +/- 3.9%) and ALEN + TRN groups (-2.7 +/- 1.0%, -5.6 +/- 2.1%, -11.2 +/- 3.7%). CONTR had further significant losses of BMD after 3 and 6 months. ALEN had no further regional BMD losses after initiation of alendronate therapy. ALEN + TRN restored BMD of the whole body, femur neck and lumbar vertebra to within 0.9%, 2.1%, and 3.4% of pre-transplantation levels, respectively. CONCLUSIONS: Resistance exercise plus alendronate was more efficacious than alendronate alone in restoring BMD in HTRs. Our results indicate that anti-osteoporosis therapy in this population should include both an anti-resorptive agent as well as an osteogenic stimulus, such as mechanical loading. 相似文献
25.
26.
Joanne I. Brodfuehrer Tracy J. Wilke David H. Kinder Garth Powis 《Cancer chemotherapy and pharmacology》1989,24(5):277-283
Summary The chemical breakdown of carmethizole [1-methyl-2-methylthio-4,5-bis-(hydroxymethyl)imidazole-4,5-bis(N-methylcarbamate)hydrochloride] and its pharmacokinetics in the mouse and beagle dog were studied. Carmethizole was relatively unstable in aqueous media, having a half-life of 1 h in 0.9% sodium chloride, human whole blood, human plasma, and dog urine at 37°C. Its major breakdown product in 0.9% sodium chloride and pH 5.0 sodium phosphate buffer was carmethizole diol. When carmethizole was added to pH 7.0 or pH 9.0 sodium phosphate buffer, the major breakdown product was carmethizole diol-4-monophosphate. Carmethizole reacted directly with glutathione at pH 8.0, forming a glutathione adduct of carmethizole monocarbamate. Elimination of the drug from the plasma of the beagle dog following i.v. bolus doses of 22.4 and 4.3 mg/kg was biphasic. At these doses the terminal half-life was 39 and 46 min, respectively, and the respective total body clearance was 4.6 and 7.7 ml/min per kg. The 22.4 mg/kg dose was lethal to the beagle dog by day 4. Elimination of carmethizole from the plasma of mice following an i. v. bolus dose of 115 mg/kg was monoexponential, with a half-life of 11.6 min and a total body plasma clearance of 43.6 ml/min per kg. When the drug was infused at 230 mg/kg over 8 h into mice, the total body clearance was 40.8 ml/min per kg. Following the i.v. bolus administration of carmethizole to mice, 30% of the total dose was excreted in urine over 3 h as carmethizole diol, 10%, as carmethizole diol-sulfate, 3.4%, as carmethizole 4-monocarbamate, and 2.4%, as unchanged drug. 相似文献
27.
We present the first case of Holt-Oram syndrome associated with the lethal congenital heart defect of hypoplastic left heart syndrome. The possible pathophysiological link is explored and the need for careful genetic and cardiologic evaluation in these patients is reiterated. 相似文献
28.
Potent inhibition of HIV-1 entry by (s4dU)35 总被引:2,自引:0,他引:2
Horváth A Tokés S Hartman T Watson K Turpin JA Buckheit RW Sebestyén Z Szöllosi J Benko I Bardos TJ Dunn JA Fésüs L Tóth FD Aradi J 《Virology》2005,334(2):214-223
29.
Differential Effects of Clostridium difficile Toxins on Tissue-Cultured Cells 总被引:13,自引:4,他引:13 下载免费PDF全文
Sam T. Donta Nadine Sullivan Tracy D. Wilkins 《Journal of clinical microbiology》1982,15(6):1157-1158
Two immunologically distinct Clostridium difficile toxins elicited similar morphological changes on cultured cells, although there were differences in both toxin potency and cell sensitivities. 相似文献
30.
Somatostatin analogue (octreotide) inhibits bile duct epithelial cell proliferation and fibrosis after extrahepatic biliary obstruction. 总被引:2,自引:0,他引:2 下载免费PDF全文
T. F. Tracy Jr A. J. Tector M. E. Goerke S. Kitchen D. Lagunoff 《The American journal of pathology》1993,143(6):1574-1578
Extrahepatic biliary obstruction leads to bile duct epithelial cell proliferation. Somatostatin and its analogue, octreotide, have been shown to inhibit DNA synthesis and proliferation in hepatocytes. We investigated the effect of octreotide on the biliary epithelial cell proliferative responses to biliary obstruction. Male Sprague-Dawley rats underwent common bile duct ligation and subcutaneous injection of either saline or octreotide (6 micrograms/kg) twice daily for 7 days. Morphometric analysis of hepatocytes, bile duct epithelial cells, and periportal connective tissue was performed by computerized point counting. Hepatocyte volume was preserved with octreotide treatment, which also significantly decreased bile duct proliferation and periportal extracellular matrix deposition in response to biliary obstruction compared with saline treated, duct-ligated animals. These results indicate that octreotide prevents the morphological changes that accompany extrahepatic biliary obstruction. 相似文献