AIM To assess potential benefits of an additional unenhanced acquisition in computed tomography angiography(CTA)in patients with suspected acute aortic syndrome(AAS).METHODS A total of 103 aortic CTA(non-electrocardio...AIM To assess potential benefits of an additional unenhanced acquisition in computed tomography angiography(CTA)in patients with suspected acute aortic syndrome(AAS).METHODS A total of 103 aortic CTA(non-electrocardiography-gated,128 slices)performed due to suspected AAS were retrospectively evaluated for acute aortic dissection(AAD),intramural hematoma(IMH),or penetrating aortic ulcer(PAU).Spiral CTA protocol consisted of an unenhanced acquisition and an arterial phase.If AAS was detected,a venous phase(delay,90 s)was added.Images were evaluated for the presence and extent of AAD,IMH,PAU,and related complications.The diagnostic benefit of the unenhanced acquisition was evaluated concerning detection of IMH.RESULTS Fifty-six(30%women;mean age,67 years;median,68 years)of the screened individuals had AAD or IMH.A triphasic CT scan was conducted in 76.8%(n=43).56%of the detected AAD were classified as Stanford type A,44%as Stanford type B.53.8%of the detected IMH were classified as Stanford type A,46.2%as Stanford type B.There was no significant difference in the involvement of the ascending aorta between AAD and IMH(P=1.0)or in the average age between AAD and IMH(P=0.548),between Stanford type A and Stanford type B in general(P=0.650)and between Stanford type A and Stanford type B within the entities of AAD and IMH(AAD:P=0.785;IMH:P=0.146).Only the unenhanced acquisitions showed a significant density difference between the adjacent lumen and the IMH(P=0.035).Subadventitial hematoma involving the pulmonary trunk was present in 5 patients(16%)with Stanford A AAD.The difference between the median radiation exposure of a triphasic(2737 mGy*cm)compared to a biphasic CT scan(2135 mGy*cm)was not significant(P=0.135).CONCLUSION IMH is a common and difficult to detect entity of AAS.An additional unenhanced acquisition within an aortic CTA protocol facilitates the detection of IMH.展开更多
An expedient synthesis of a series of configurationally stable oxa[5]helicenes,oxa[6]helicenes,and dioxa[6]helicenes has been developed using an intramolecular,highly enantioselective,Au-catalyzed,alkyne hydroarylatio...An expedient synthesis of a series of configurationally stable oxa[5]helicenes,oxa[6]helicenes,and dioxa[6]helicenes has been developed using an intramolecular,highly enantioselective,Au-catalyzed,alkyne hydroarylation reaction.The absolute configuration of the newly prepared structures has been established by crystallography,their inversion barriers have been determined theoretically and experimentally,and their chiroptical properties have been investigated.Comparison of these data with those reported for thia-or carbohelicenes sharing an otherwise identical helical framework enables the establishment of comprehensive correlations between the nature of the embedded(hetero)atom(s)and the magnitude of these properties.Preliminary studies on the postsynthetic functionalization of the oxahelicenes obtained are also described.Specifically,siteselective bromination at the 15-position in oxa[5]helicene 5d allows its subsequent manipulation into pyridine-containing aza-oxa[7]helicene 13d;while the two termini of oxa[6]helicene 7d have been intramolecularly cyclised into the pleiadeno[1,12,11-bcde]benzofuran derivative 15d by acidic treatment.Both transformations take place without erosion of the enantiopurity.展开更多
文摘AIM To assess potential benefits of an additional unenhanced acquisition in computed tomography angiography(CTA)in patients with suspected acute aortic syndrome(AAS).METHODS A total of 103 aortic CTA(non-electrocardiography-gated,128 slices)performed due to suspected AAS were retrospectively evaluated for acute aortic dissection(AAD),intramural hematoma(IMH),or penetrating aortic ulcer(PAU).Spiral CTA protocol consisted of an unenhanced acquisition and an arterial phase.If AAS was detected,a venous phase(delay,90 s)was added.Images were evaluated for the presence and extent of AAD,IMH,PAU,and related complications.The diagnostic benefit of the unenhanced acquisition was evaluated concerning detection of IMH.RESULTS Fifty-six(30%women;mean age,67 years;median,68 years)of the screened individuals had AAD or IMH.A triphasic CT scan was conducted in 76.8%(n=43).56%of the detected AAD were classified as Stanford type A,44%as Stanford type B.53.8%of the detected IMH were classified as Stanford type A,46.2%as Stanford type B.There was no significant difference in the involvement of the ascending aorta between AAD and IMH(P=1.0)or in the average age between AAD and IMH(P=0.548),between Stanford type A and Stanford type B in general(P=0.650)and between Stanford type A and Stanford type B within the entities of AAD and IMH(AAD:P=0.785;IMH:P=0.146).Only the unenhanced acquisitions showed a significant density difference between the adjacent lumen and the IMH(P=0.035).Subadventitial hematoma involving the pulmonary trunk was present in 5 patients(16%)with Stanford A AAD.The difference between the median radiation exposure of a triphasic(2737 mGy*cm)compared to a biphasic CT scan(2135 mGy*cm)was not significant(P=0.135).CONCLUSION IMH is a common and difficult to detect entity of AAS.An additional unenhanced acquisition within an aortic CTA protocol facilitates the detection of IMH.
基金the Deutsche Forschungsgemeinschaft(INST 186/1352-1 and INST 186/1237-1)is gratefully acknowledged.W.Fthanks the China Scholarship Council for PhD fellowship support.R.C.-L.gratefully acknowledges grant PID2021-127964NB-C22 funded by the MCIN/AEI/10.13039/501100011033.
文摘An expedient synthesis of a series of configurationally stable oxa[5]helicenes,oxa[6]helicenes,and dioxa[6]helicenes has been developed using an intramolecular,highly enantioselective,Au-catalyzed,alkyne hydroarylation reaction.The absolute configuration of the newly prepared structures has been established by crystallography,their inversion barriers have been determined theoretically and experimentally,and their chiroptical properties have been investigated.Comparison of these data with those reported for thia-or carbohelicenes sharing an otherwise identical helical framework enables the establishment of comprehensive correlations between the nature of the embedded(hetero)atom(s)and the magnitude of these properties.Preliminary studies on the postsynthetic functionalization of the oxahelicenes obtained are also described.Specifically,siteselective bromination at the 15-position in oxa[5]helicene 5d allows its subsequent manipulation into pyridine-containing aza-oxa[7]helicene 13d;while the two termini of oxa[6]helicene 7d have been intramolecularly cyclised into the pleiadeno[1,12,11-bcde]benzofuran derivative 15d by acidic treatment.Both transformations take place without erosion of the enantiopurity.
