ABSTRACT
Purpose To explore the feasibility of low radiation dose combined with lowdose contrast agent in thyroid CT enhanced scan and investigate the benefit of reducing radiation hazard and contrast agent damage to thyroid.Materials and Methods 120 patients assigned for thyroid enhanced CT scan were prospectively and randomly divided into four groups (each group was 30 patients).Group A:radiation dose 120 kV,180 mA,contrast agent dose 1.2 ml/kg;group B:radiation dose 120 kV,180 mA,contrast agent dose 1.0 ml/kg;group C:radiation dose 100 kV,100 mA,contrast agent dose 1.2 ml/kg;group D:radiation dose 100 kV,100 mA,contrast agent dose 1.0 ml/kg.CT values,background sign,background noise of thyroid were measured;signal to noise ratio (SNR) and contrast to noise ratio (CNR) were calculated;CT dose index of volume (CTDIvol),dose length product (DLP),and the effective dose (ED) were recorded and calculated.The image quality was evaluated and the data was statistically analyzed by two radiologists.Results CT values,background sign and background noise of thyroid,as well as CTDIvol,DLP,ED among four groups were statistical significant (P＜0.05);there was no significant difference in SNR,CNR and image quality scores among four groups (P＞0.05).Conclusion It is beneficial of reducing radiation hazard and side-effect of contrast agent from low radiation dose combined with low-dose contrast agent under the condition of ensuring diagnostic image quality.
ABSTRACT
Objective To evaluate the value of multi-slice spiral CT Low-dose scanning technology in thyroid enhanced scan. Methods Eighty patients were randomly divided into four groups including Group A:120 kV,180 mA;Group B:120 kV,100 mA;Group C:100 kV,180 mA and Group D:100 kV,100 mA.The subjective image quality was evaluated and scored.Thyroid CT val-ue,image background noise (N),image signal to noise ratio (SNR),CT dose index (CTDIvol),dose length product (DLP),and the effective radiation dose (ED)were measured and compared.Results The subjective image scores and SNR of these four groups were 3.90±0.31 and 26.34±3.13,3.75±0.44 and 25.08 ±1.87,3.70 ±0.47 and 25.86 ±2.38,3.60 ±0.60 and 24.87 ±2.20 respectively.There were no significantly statistical differences among the subjective image scores and SNR (P > 0.05 )of the 4 Groups.Thyroid CT values,N,CTDIvol,DLP and ED were (1 68.55 ± 13.39)HU,(6.48 ±0.84)HU,(10.95 ±0.00)mGy, (145.67±8.79)mGy·cm,(0.73±0.04)mSv in Group A,(170.70±11.34)HU,(6.83±0.45)HU,(6.08±0.00)mGy,(84.58± 4 .9 4)mGy· cm,(0 .4 2 ±0 .0 3 )mSv in Group B,(1 8 5 .2 0 ±2 2 .3 5 )HU,(7 .1 9 ±0 .8 6 )HU,(6 .5 9 ±0 .0 0 )mGy,(8 9 .8 6 ± 3 .2 6 )mGy· cm,(0 .4 5 ±0 .0 3 )mSv in Group C,(1 9 0 .5 5 ±2 1 .3 8 )HU,(7 .6 6 ± 1 .0 1 )HU,(3 .6 6 ±0 .0 0 )mGy,(5 0 .2 0 ± 1 .8 9 )mGy·cm,(0.25±0.01)mSv in Group D respectively.There were significantly statistical differences among different thyroid CT values,N,CTDIvol,DLP and ED (P <0.05).Conclusion Multi-slice spiral CT low-dose scanning technology in thyroid en-hanced scan can guarantee the image quality and effectively reduce thyroid radiation dose.
ABSTRACT
Objective:To evaluate the value of CT findings in the diagnosis of laryngeal carcinoma infiltration extent.Method:The data of comparison of CT findings and clinico-pathologic stages on 61 patients with laryngeal carcinoma were analyzed from 1995 to 1999.There were 58 males and 3 females ,ranging in age from 37 to 83 years old which stages were T1N0M0 in 11,T2N0M0 in 21,T2N1M0 in 9,T2N2M0 in 1,T2N3M0 in 1,T3N0M0 in 10,T3N1M0 in 2,T4N0M0 in 4 and T4N1M0 in 2,respectively.And the supraglottic cancer was 11(18.0%,11/61),glottic cancer 47(77.1%,47/61),transglottic cancer 3(4.9%,3/61),respectively.The CT examination and surgical treatment were made in all 61 patients.Results:The correct rate at CT findings was 91.8%(56/61),and the accurate rate of clinical stage was 73.8%(45/61).These results showed different significance (P＜0.05).Conclusion:The CT findings showed valuable in the diagnosis to infiltration extent of laryngeal carcinoma and clinical significance for surgical treatment of patients with laryngeal carcinoma.
ABSTRACT
Objective To evaluate the diagnostic values of diffusion tensor imaging(DTI)in early radiation-induced brain injury of the temporal lobes.Methods Conventional and MR diffusion tensor imaging examinations were performed in 23 patients following radiotherapy for nasopharyngeal carcinoma(NPC)and in 28 age-matched healthy controls.Isotropic apparent diffusion coefficient(ADCiso)and anisotropic index were measured in the white matter on both of the temporal lobes.Results The value of ADCiso,fractional anisotropy(FA),relative anisotropy(RA)and 1 minus volume ratio(1-VR)were(644.08?56.80)?10-6 mm2/s,0.394?0.074,0.344?0.075 and 0.182?0.072 respectively.In comparison with control group,these values were significant decreased(P