Diagnostic accuracy of 64-slice computed tomography compared with coronary angiography

Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenObjective: The aim of this study was to evaluate the diagnostic accuracy (sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV)) of 64-slice multidetector computed tomography (MDCT) compared with quantitative coronary angiography (QCA) for detection of coronary artery disease (CAD). Material and methods: Sixty-nine patients participating in a study of coronary in-stent restenosis were investigated. After a 64-slice MDCT scan patients were evaluated by QCA. The coronary arteries were divided into 15 segments and stenosis was graded for each segment by both methods. The diagnostic accuracy of 64-slice MDCT was evaluated using the QCA as the gold standard. Results: Among the 69 patients included in the study 13 (19%) were female and 56 male. The mean age was 63 (SD 10) years. The following risk factors were present: high blood pressure 67%, elevated blood cholesterol 54%, diabetes 12% and family history of CAD 71%. Current smokers were 22% and previous smokers were 48%. Altogether 663 segments were examined. Of those 221 (33%) segments were excluded; 103 because of stents, 48 because of heavy calcification, 41 because of motion artifacts and 29 because the segments were less than 1.5 mm in diameter. The mean time between MDCT and QCA was 6.3 (SD 12.1) days. The sensitivity of 64-slice MDCT for diagnosing significant stenosis (>/= 50% according to QCA) was 20%, the specificity was 94%, PPV was 16%, NPV was 95% and the accuracy was 89%. Conclusion: High NPV and specificity indicates that MDCT is useful for accurately excluding significant CAD but the low sensitivity and low PPV indicate that the method is not accurate in diagnosing coronary artery stenosis of 50% or more according to QCA. Key words: coronary artery disease, multidetector computed tomography, cardiac catheterisation. Correspondence: Karl Andersen, [email protected]: Markmið rannsóknarinnar var að meta greiningarhæfni (næmi, sértæki, jákvætt forspárgildi, neikvætt forspárgildi og nákvæmni) 64 sneiða tölvusneiðmyndatækni (TS-tækni) á kransæðasjúkdómi með hjartaþræðingu sem viðmið. Efniviður og aðferðir: Rannsóknarhópurinn samanstóð af 69 sjúklingum sem tóku þátt í rannsókn á endurþrengslum í stoðnetum kransæða. Framkvæmd var TS af kransæðum til að meta æðaþrengsli. Nokkrum dögum síðar voru þátttakendur hjartaþræddir. Kransæðatrénu var skipt upp í 15 hluta. Æðaþrengsli voru metin í öllum hlutum æðatrésins með báðum aðferðunum. Greiningarhæfni 64 sneiða TS-tækni var metin og kransæðaþræðing höfð sem viðmið. Niðurstöður: Í rannsókninni voru 13 (19%) konur og 56 karlar. Meðalaldur þátttakenda var 63 (SD 10) ár, háþrýsting höfðu 67%, háar blóðfitur 54%, sykursýki 12% og ættarsaga um kransæðasjúkdóm var til staðar í 71% tilvika. Reykingamenn voru 22% og fyrrum reykingamenn 48%. Samtals 663 æðahlutar voru rannsakaðir. Af þeim voru 221 (33,4%) útilokaðir; 103 vegna stoðneta, 48 vegna truflana af völdum kalks, 41 vegna hreyfitruflana og 29 þar sem æðin var minni en 1,5 mm í þvermál. Meðaltími milli TS og hjartaþræðingar voru 6,3 (SD 12,1) dagar. Næmi 64 sneiða TS til greiningar marktækra þrengsla (?50% þrengsli samkvæmt hjartaþræðingu) var 20%, sértæki 94%, jákvætt forspárgildi 16%, neikvætt forspárgildi 95% og nákvæmni 89%. Ályktun: Hátt neikvætt forspárgildi og hátt sértæki gefur til kynna að TS-rannsókn sé gagnleg til að útiloka kransæðasjúkdóm. Lágt næmi og lágt jákvætt forspárgildi benda til að aðferðin sé ekki góð til að meta hvort kransæðaþrengsli séu 50% eða meiri við hjartaþræðingu

A Study of the PDGF Signaling Pathway with PRISM

In this paper, we apply the probabilistic model checker PRISM to the analysis of a biological system -- the Platelet-Derived Growth Factor (PDGF) signaling pathway, demonstrating in detail how this pathway can be analyzed in PRISM. We show that quantitative verification can yield a better understanding of the PDGF signaling pathway.Comment: In Proceedings CompMod 2011, arXiv:1109.104

Autocrine PDGF stimulation in malignancies

Platelet-derived growth factor (PDGF) isoforms are important mitogens for different types of mesenchymal cells, which have important functions during the embryonal development and in the adult during wound healing and tissue homeostasis. In tumors, PDGF isoforms are often over-expressed and contribute to the growth of both normal and malignant cells. This review focuses on tumors expressing PDGF isoforms together with their tyrosine kinase receptors, thus resulting in autocrine stimulation of growth and survival. Patients with such tumors could benefit from treatment with inhibitors of either PDGF or PDGF receptors