Ghost artifacts occur in magnetic resonance imaging （MRI） reconstruction because odd and even echoes have different phase offsets. A method based on the projection in hybrid-space is described to remove ghost artifa...Ghost artifacts occur in magnetic resonance imaging （MRI） reconstruction because odd and even echoes have different phase offsets. A method based on the projection in hybrid-space is described to remove ghost artifacts. First, the projection of the even and odd lines along phase-encoding direction in hybrid-space was used to estimate the phase difference between odd and even echoes. Secondly, we fit the phase difference and used it to correct the phase of even or odd echoes. Finally, the corrected image was obtained by performing the inverse Fourier transform along phase-encoding direction in hybrid-space. The experimental results show that linear and nonlinear differences can be corrected and the intensity of ghost artifacts is significantly reduced. The effectiveness of the proposed method is demonstrated in ghost artifact removal.展开更多
Objective： To compare the effectiveness of digital mammography and MRI in the detection and diagnosis of breast cancer and to assess the value of these modalities as well as the combination of the two. Methods： Sixt...Objective： To compare the effectiveness of digital mammography and MRI in the detection and diagnosis of breast cancer and to assess the value of these modalities as well as the combination of the two. Methods： Sixty-seven patients with surgery and pathology proved breast lesion （malignant, n = 32; benign, n = 46） underwent digital mammography and MRI, the pulse sequences included T1WI, T2WI, diffuse weighted imaging （DWI）, and dynamic contrast-enhanced MRI before surgery. Of the results of these two modalities, all lesions were classified into 5 groups according to BI-RADS classification, and the imaging findings were correlated to histopathology. The sensitivity and specificity of each modality as well as the combination of the two were calculated. Results： Of these 78 breasts lesions, The sensitivity was 78.13%% （25/32） for digital mammography and 93.75% （30/32） for MRI （P 〉 0.05）. The specificity was 73.91%% （34/46） and 89.13% （41/46） accordingly （P 〈 0.05）, both of them showed statistical difference. The sensitivity and specificity was 98.63% and 97.16% respectively as these two modalities were used in combination. Conclusion： Digital mammography in combination with MRI is helpful in the diagnosis of breast cancer, the sensitivity and specificity was enhanced when compared to that of single modality.展开更多
文摘Ghost artifacts occur in magnetic resonance imaging （MRI） reconstruction because odd and even echoes have different phase offsets. A method based on the projection in hybrid-space is described to remove ghost artifacts. First, the projection of the even and odd lines along phase-encoding direction in hybrid-space was used to estimate the phase difference between odd and even echoes. Secondly, we fit the phase difference and used it to correct the phase of even or odd echoes. Finally, the corrected image was obtained by performing the inverse Fourier transform along phase-encoding direction in hybrid-space. The experimental results show that linear and nonlinear differences can be corrected and the intensity of ghost artifacts is significantly reduced. The effectiveness of the proposed method is demonstrated in ghost artifact removal.
文摘Objective： To compare the effectiveness of digital mammography and MRI in the detection and diagnosis of breast cancer and to assess the value of these modalities as well as the combination of the two. Methods： Sixty-seven patients with surgery and pathology proved breast lesion （malignant, n = 32; benign, n = 46） underwent digital mammography and MRI, the pulse sequences included T1WI, T2WI, diffuse weighted imaging （DWI）, and dynamic contrast-enhanced MRI before surgery. Of the results of these two modalities, all lesions were classified into 5 groups according to BI-RADS classification, and the imaging findings were correlated to histopathology. The sensitivity and specificity of each modality as well as the combination of the two were calculated. Results： Of these 78 breasts lesions, The sensitivity was 78.13%% （25/32） for digital mammography and 93.75% （30/32） for MRI （P 〉 0.05）. The specificity was 73.91%% （34/46） and 89.13% （41/46） accordingly （P 〈 0.05）, both of them showed statistical difference. The sensitivity and specificity was 98.63% and 97.16% respectively as these two modalities were used in combination. Conclusion： Digital mammography in combination with MRI is helpful in the diagnosis of breast cancer, the sensitivity and specificity was enhanced when compared to that of single modality.
