目的分析腹部侵袭性纤维瘤病(AF)的CT and MRI表现,以提高对本病诊断准确性。方法回顾性分析经病理证实的23例侵袭性纤维瘤病患者的临床及影像学资料。结果23例腹部AF患者中,15例为腹壁型,8例为腹内型10例呈浸润性生长,边界不清,与腹肌...目的分析腹部侵袭性纤维瘤病(AF)的CT and MRI表现,以提高对本病诊断准确性。方法回顾性分析经病理证实的23例侵袭性纤维瘤病患者的临床及影像学资料。结果23例腹部AF患者中,15例为腹壁型,8例为腹内型10例呈浸润性生长,边界不清,与腹肌、髂肌、周围血管、系膜及脏器分界不清。13例呈膨胀性生长,边界清楚。CT检查19例,平扫病变呈等密度3例,稍低密度6例,10例呈不均质混杂密度。所有病变中没有钙化、脂肪及坏死。增强扫描16例动脉期及静脉期呈不均匀轻度强化,延迟期中等或明显强化,其中,12例病变内见条片状及斑片状稍低密度无强化灶。MRI检查16例中,T2加权像及弥散加权成像不均匀稍高信号,T1加权成像呈等信号7例,稍低信号9例,脂肪抑制T2加权序列,病灶呈明显高信号。增强扫描动脉期及静脉期呈渐进性不均匀轻、中度强化,延迟期呈渐进性明显强化。结论腹部AF的CT和MRI表现具有一定的特征性,对AF的诊断和鉴别诊断有重要价值。展开更多
The dynamic response of an infinite beam placed on a Pasternak foundation when the system was subjected to a moving load was investigated.We used the double Fourier transform and its inversion to solve the formulation...The dynamic response of an infinite beam placed on a Pasternak foundation when the system was subjected to a moving load was investigated.We used the double Fourier transform and its inversion to solve the formulations of the problem.A closed form analytic solution of the beam was obtained by the theorem of residues.We selected a numerical example to illustrate the dynamic response of the beam on Pasternak and Winkler foundations,respectively.We discuss the effect of the moving load velocity on the dynamic displacement response of the beam.The maximum deflection of the beam increases slightly with increased load velocity but increases significantly with reduced shear modulus of subgrade at a given velocity.The maximum deflection of a beam resting on a Pasternak foundation is much smaller than that of a beam on a Winkler foundation.展开更多
文摘目的分析腹部侵袭性纤维瘤病(AF)的CT and MRI表现,以提高对本病诊断准确性。方法回顾性分析经病理证实的23例侵袭性纤维瘤病患者的临床及影像学资料。结果23例腹部AF患者中,15例为腹壁型,8例为腹内型10例呈浸润性生长,边界不清,与腹肌、髂肌、周围血管、系膜及脏器分界不清。13例呈膨胀性生长,边界清楚。CT检查19例,平扫病变呈等密度3例,稍低密度6例,10例呈不均质混杂密度。所有病变中没有钙化、脂肪及坏死。增强扫描16例动脉期及静脉期呈不均匀轻度强化,延迟期中等或明显强化,其中,12例病变内见条片状及斑片状稍低密度无强化灶。MRI检查16例中,T2加权像及弥散加权成像不均匀稍高信号,T1加权成像呈等信号7例,稍低信号9例,脂肪抑制T2加权序列,病灶呈明显高信号。增强扫描动脉期及静脉期呈渐进性不均匀轻、中度强化,延迟期呈渐进性明显强化。结论腹部AF的CT和MRI表现具有一定的特征性,对AF的诊断和鉴别诊断有重要价值。
文摘The dynamic response of an infinite beam placed on a Pasternak foundation when the system was subjected to a moving load was investigated.We used the double Fourier transform and its inversion to solve the formulations of the problem.A closed form analytic solution of the beam was obtained by the theorem of residues.We selected a numerical example to illustrate the dynamic response of the beam on Pasternak and Winkler foundations,respectively.We discuss the effect of the moving load velocity on the dynamic displacement response of the beam.The maximum deflection of the beam increases slightly with increased load velocity but increases significantly with reduced shear modulus of subgrade at a given velocity.The maximum deflection of a beam resting on a Pasternak foundation is much smaller than that of a beam on a Winkler foundation.