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Objective To analyze the CT pulmonary angiography(CTPA) image quality and radiation dose of obesity patients with high and low tube voltage iterative reconstruction(IR) and the filtered back projection(FBP) reconstruct algorithm,and to explore the feasibility of low tube voltage IR algorithms in CTPA of obese patients.Methods Obese patients with suspected pulmonary embolism were randomly assigned into 80 kV or 120 kV group, and the images were treated with IR and FBP reconstructions.CT value of the basal segment of the right pulmonary artery, right upper lobe and main pulmonary artery were measured, and the average CT value of the pulmonary artery was further calculated, and the independent sample t test analysis was used.Results Comparing the CT value of the IR and FBP subgroup of two tube voltage groups, the differences were not significant (P>0.05), the differences of noise, signal noise ratio(SNR) and contrast noise ratio (CNR) were statistically significant (P<0.05), respectively.The CT value,noise,SNR and CNR of 80 kV group were significantly higher than those of the 120 kV group, and the differences were statistically significant (P<0.05), while the radiation dose were significantly lower than those of 120 kV group (P=0.000).Conclusion The CTPA image quality of 80 kV IR algorithm is significantly improved compared with the 120 kV FBP algorithm, and the radiation dose is significantly reduced, which could be used for CT pulmonary angiography in obese patients.
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Objective To assess the effects of different level iterative reconstructions (IR) on image quality of obese patients of 80 kV CT pulmonary angiography (CTPA).Methods Forty obese patients with clinically suspected pulmonary embolism were examined with CTPA,filtered back projection method (FBP) and three IR levels (iDose1,20％ IR/80％ FBP;iDose3,40％ IR/60％ FBP;iDose5,60％ IR/40％ FBP) to reconstruct images were used.The CT value of pulmonary artery trunk,upper lobe artery and lower lobe basal segment artery of right pulmonary were measured,and the image noise,SNR and CNR of four groups were calculated and compared.Results The image noise,SNR and CNR had significant difference in 4 groups (all P＜0.05),and the image noise had significant difference between each two groups (all P＜0.05),the SNR and CNR had statistical difference between FBP and iDose3,between FBP and iDose5 (P＜0.01).Conclusion Compared with FBP,80 kV combined with different level IR technologies can significantly decrease image noise and improve objective image quality in CTPA,the radiation dose that obese patients received can be reduced.
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<p><b>OBJECTIVE</b>To evaluate the left ventricular (LV) radial and longitudinal systolic function in hypertrophic cardiomyopathy (HCM) patients by 3.0 T MR.</p><p><b>METHODS</b>Sixteen HCM (HCM group) and twenty normal adults (normal group) were examined with fast imaging employing steady-state (FIESTA) acquisition sequence of cardiac MRI. LV ejection fraction (LVEF), longitudinal shortening (LS) and fractional shortening (FS) in three standard levels were measured to analyze LV radial and longitudinal systolic function.</p><p><b>RESULTS</b>Asymmetric hypertrophy was detected in all HCM patients. The LVEF and FS were significantly higher while LS was significantly lower in HCM group than those in normal group (P < 0.05 or 0.01). FS at basal and middle levels were significantly higher in HCM group than in normal group (both P < 0.01). FS in apex level was similar in the two groups (P = 0.057). Pearson correlation analysis showed that LS was negatively related with the number of hypertrophy segments in HCM patients (r = -0.537, P = 0.032). But there was no correlation between FS and the number of hypertrophy segments as well as FS and LS in HCM patients (r = -0.090, P = 0.739; r = 0.049, P = 0.856).</p><p><b>CONCLUSION</b>The LV longitudinal systolic function was reduced but the LV radial systolic function remained unchanged in HCM patients, thus, LS changes could better reflect myocardial systolic function in HCM patients.</p>
Subject(s)
Adult , Humans , Cardiomyopathy, Hypertrophic , Heart Ventricles , Magnetic Resonance Imaging , Myocardium , Systole , Ventricular Dysfunction, Left , Ventricular Function, LeftABSTRACT
<p><b>OBJECTIVE</b>To establish cardiac magnetic resonance imaging(MRI) derived left ventricular (LV) global and region function parameters in normal adults.</p><p><b>METHODS</b>Twenty normal adults were examined with fast imaging employing steady-state(Fiesta) acquisition sequence of cardiac MRI, LV global function and LV region function were measured at basal, middle, apical level and at 16 LV segments. The regional function parameters among different levels and different segments of the same level were analyzed.</p><p><b>RESULTS</b>(1)LV global function: end-diastolic volume (109.17 ± 19.52) ml; end-systolic volume (37.76 ± 14.16) ml;ejection fraction (65.93 ± 7.79) %; wall thickening (83.24 ± 40.82) %; longitudinal shortening (15.51 ± 3.78) %; fractional shortening (31.78 ± 9.55) %;end-diastolic mass (95.20 ± 19.95) g. (2)LV regional function: In each LV level, there was no significant difference in end-systolic wall thickness (P > 0.05). End-diastolic wall thickness and wall thickening were similar between the middle and apical levels, but there were significant differences between middle and apical levels with the basal level(both P < 0.05). End-systolic wall thickness of the middle and the apical level was similar, but there were significant differences between middle and apical levels with the basal level (both P < 0.05). At the segments of the same level, end-diastolic wall thickness and the relevant regional function parameters between the segments of anteroseptal and inferoseptal at base and middle level were similar (P > 0.05); the end-diastolic wall thickness was the largest and the WT was the minimal at the septal segments of three levels, and the difference were significant between the septal and other segments in the same level (P < 0.05).</p><p><b>CONCLUSIONS</b>Fractional shortening and longitudinal shortening provide new indicators for assessing LV global function by cardiac MRI. There is obvious heterogeneity on LV regional function in normal adults, systolic function is the strongest in apical level and the weakest in spetal segments of LV.</p>