| Objectives 1 To explore the application value of imaging about reducing the dosage of contrast Medium in intracranial and cervical artery imaging with 256-slice CT(MSCT).2To assess the effect of reduced x-ray tube voltage, low iodine concentration contrast medium on image quality at intracranial and cervical artery imaging with 256-slice CT.3To explore the effect of different threshold preset value in image quality of 256-slice CT intracranial and cervical angiography.Methods 1 100 cases of patients with similar age,height,weight and with the inspection of 256-slice CT intracranial and cervical angiography were selected,they were divided into group A(routine) and group B(low-dose) randomly,and each group includes 50 patients,besides the contrast Medium is Ultravist Solution(370mg/ml).In group A,the contrast Medium dose tailored to the patient’s body weight(1.0m L/kg),In group B,the contrast Medium was(weight×1.0m L/kg-10)m L.Measuring the CT value of arch of the aorta,common carotid artery,internal carotid artery and middle cerebral artery.2 80 cases of patients with the inspection of 256-slice CT intracranial and cervical angiography were selected.They were divided into group A(routine) and group B(double low-dose)randomly,and each group includes 40 patients.In group A,120 k Vp tube voltage with 370 mg I/m L contrast medium concentration;In group B,100 k Vp tube voltage with 320 mg I/m L contrast medium concentration.The contrast Medium dose tailored to the patient’s body weight(1.0m L/kg).Both of the two group reconstruction were performed with i Dose iterative reconstruction.The images quality,The total amount of iodine and effective radiation dose were record.3 120 patients who underwent CT intracranial and cervical angiography were randomly divided into 3 groups.In group A, the threshold preset value was set at 150 HU.In group B, the threshold preset value was set at 120 HU.In group C, the threshold preset value was set at 90 HU.Measuring the CT value of common carotid artery and middle cerebral artery.Measuring the CT value of arch of the aorta,common carotid artery,internal carotid artery and middle cerebral artery.The mean image quality score,enhancement of intracranial and cervical artery imaging was record.Results 1,The contrast Medium dose of the low-dose group and routine group were55.42±7.08 m L and 64.92±7.32 m L,there were statistically significant between the two groups(P<0.05). The routine group about the enhancement of arch of the aorta,common carotid artery,internal carotid artery and middle cerebral artery were 427.28 ±57.02 HU,441.02±5.8HU,420.71±58.55 HU,421.34±60.46;The low-dose group about the enhancement of arch of the aorta,common carotid artery,internal carotid artery and middle cerebral artery were 388.81 ± 52.84 HU,399.25 ± 57.08 HU,386.02 ±51.52 HU,372.6 ± 59.48 HU,there were statistically significant between the two groups(P<0.05).The two groups of the intracranial and cervical artery image qualitydifference were not statistically significant(P> 0.05). 2 The routine group about the enhancement of arch of the aorta,common carotid artery,internal carotid artery and middle cerebral artery were 420.28 ± 56.02 HU,449.07 ± 57.81 HU,429.71 ±58.58 HU,421.34±60.16HU;The double low-dose group about the enhancement of arch of the aorta,common carotid artery,internal carotid artery and middle cerebral artery were428.83±52.84 HU,439.75±56.18 HU,427.02±59.52 HU,423.69±59.78 HU,there were no statistically significant(P>0.05).The effective radiation dose about the double lowdose group and routine group were 2.67 ± 0.33 m Sv and 4.05 ± 0.37 m Sv,there were statistically significant between the two groups(P<0.05).The total amount of iodine about the double low-dose group and routine group were 20.18 ± 2.13 g I and 23.16 ±2.32 g I,there were statistically significant between the two groups(P<0.05).The two groups of the intracranial and cervical artery image quality difference were not statistically significant(P> 0.05).The two groups of the intracranial and cervical artery image quality difference were not statistically significant(P> 0.05).3 In group A, the CT value of common carotid artery and middle cerebral artery were 420.28±46.02 HU and421.34 ± 45.16HU;In group B, the CT value of common carotid artery and middle cerebral artery were 408.83±52.84 HU and 413.21±58.78HU;In group C, the CT value of common carotid artery and middle cerebral artery were 311.22±39.22 HU and 339.08±33.21 HU.There was no statistically differencebetween group A and B(P> 0.05);there were statistically significant between group C with the two groups(P<0.05).The mean time from contrast injection to the scanning of the three groups were:group A,12.26±1.57s;group B,10.23 ± 2.24s;group C,7.76 ± 3.49 s,there were statistically significant between the three groups(P<0.05).The intracranial and cervical artery image quality:there were statistically significant between group C with the two groups(P<0.05).Conclusions 1 Using low-dose contrast agent in intracranial and cervical artery imaging with 256-slice CT is feasible, can obtain satisfactory images,to meet diagnostic needs.2 Reduced x-ray tube voltage and use low iodine concentration contrast medium at intracranial and cervical artery imaging with 256-slice CT, can obtain satisfactory images to meet diagnostic needs,while also can reduce the effective radiation dose and iodine intake.3 The threshold preset value 120 HU can provide satisfactory images and cut down the mean time from contrast injection to the scanning,reduce contrast material injection doseat the same time. |
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