ABSTRACT
Objective To evaluate the value of iterative modal reconstruction (IMR) for reducing radiation dose and controlling image quality in cardiac CT. Methods Ten pigs were included. All pigs were scanned on a 256?slice prospectively ECG?gated cardiac CT utilizing routine dose (group A) and tube current reduced by 30%(group B), 50%(group C) and 70%(group D), respectively. Filtered back projection (FBP), hybrid iterative reconstruction (iDose4) and IMR were used for all data, respectively. Image noise and contrast?to?noise ratio (CNR) of ascending aortic root were measured, while overall image quality and coronary artery image quality was rated (five point scale). All results reconstructed by FBP, iDose 4 and IMR were compared. Objective measurements were compared with one?way analysis of variance, and subjective assessments were compared with Kruskal?Wallis H test andχ2 test. Results Compared with that of FBP and iDose4, image noise of IMR was(15.1 ± 6.1),(18.8 ± 5.5),(22.1 ± 4.8)and(33.0 ± 4.0)HU, respectively in group A, B, C and D with significant reduction (F=82.77, 90.71, 96.59, 95.51 respectively, all P0.05) in the diagnosis rates of proximal coronary arteries compared with that using FBP and iDose4, while group C (100%, 40/40) and group D(92%, 37/40) had significantly increased diagnosis rates (χ2=20.05, 45.72, both P<0.01). The diagnosis rates of distal coronary arteries of IMR reconstruction which were 100%(50/50), 98%(49/50), 90%(45/50), 78%(39/50), respectively in groups A, B, C, D had significant increase compared with that of FBP and iDose4 reconstruction (χ2=7.39, 16.75, 34.62, 81.33, all P<0.05). Conclusions IMR can significantly reduce image noise, improve CNR and image quality compared with iDose4. Application of IMR can reduce radiation dose but without compromising image quality.
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Objective To investigate the methods for localization of the lung segments on three-dimentional (3D) pulmonary perfusion SPECT/CT imaging.Methods Twelve healthy adults were recruited into this study.Lung segments were defined based on the anatomical criteria of CT on transaxial, sagittal and coronal images, including apical, posterior, anterior segments in right upper lobe ( RUL), lateral, medial segments in right middle lobe ( RML), superior, anterior basal, lateral basal, posterior basal segments in right lower lobe (RLL); apical posterior, anterior, superior lingual, inferior lingual segments of left upper lobe ( LUL), superior, medioanterior basal, lateral basal, posterior basal segments of left lower lobe (LLL).Results (1) Eleven typical sections were selected on transaxial SPECT pulmonary perfusion imaging:sternoclavicular joint, supra-arch vessels, aortic arch, azygous arch, right upper lobar bronchus, left upper lobar bronchus, middle lobar or lingual bronchus, basal trunk of bronchus, lower lobar vein, superior and inferior basal vein and basal vein.(2) Twelve typical sections were defined on sagittal imaging:left hilum, bifurcation of left principal bronchus, septa of left pulmonary artery, cardiac apex, the first and second sections left to cardiac apex; right hilum, bifurcation of intermite bronchus, interlobar artery, bifurcation of interlobar artery, the second and third sections right to right atrium.(3) Seven typical sections were defined on coronal imaging:sternoclavicular joint, ascending aorta, bifurcation of pulmonary artery, bifurcation of trachea, intermite bronchus, basal vein and thoracic aorta.Conclusion The developed method was able to localize lung segments on pulmonary perfusion SPECT imaging.
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Objective To evaluate the diagnostic significance of full-field digital mammography (FFDM)for atypieal breast cancer findings.Methods Seven hundred-eighteen cases with breast cancer were examined using FFDM and atypical mammographic findings were found in 134 cases.Craniocaudal (CC)view and mediolateral oblique(MLO)view were conducted for each patient.Mediolateral view or spot view Was achieved if necessary.Preoperative localization Was conducted for the patients with nonpalpable breast cancer8.Results (1)The masses with well.circumscribed margin on mammography were more common in infiltrating duetal carcinoma(22/106),mucinous carcinoma(8/10),medullary carcinoma (5/6),and increased with age and reduction of the mass density.(2)Long spieulation,architectural distortion,patchy high density were mainly found in infiltrating ductal carcinoma and 30-40(24 cases),41-50(34 cases)years old patients.Long speculation wag mainly found in 30-40 years old patients (10/30).(3)Hish homogenous density and subcutaneous edema in the entire breast and mass-like area were most ffequendy found in infiltrating ductal carcinoma at 30-40(2 cases)and 41-50(5 cases)years old.High density and subcutaneous edema were only found in dense breast(8 cases).Conclusion The atypical findings of breast cancer in foil-field digital mammography are associated with the pathological type of cancer.patient age and the gland density of the breast.