The Technology Optimization Of Gemstone Spectral Imaging And Its Application In Intractable Examination

Recently,Gemstone Spectral Imaging(GSI)has become the radiological examination of choice for noninvasive imaging of arteries and organs in various body regions,and its auxiliary role in the diagnosis of clinical diseases is becoming more and more obvious.However,the amount of radiation exposure to the patient population of GSI and its risks has also drawn radiologists attention.With the wide application of iodine contrast media in clinical,the side effects of its use are a source of increasing concern,contrast induced nephropathy,in particular.Therefore,the risk of adverse effects on the radiation dose and iodine intake,and reducing the radiation dose and iodine intake should be carefully considered when selecting and optimizing CT scan modes,scan protocols and clinical applications,and still maintaining diagnostic image quality.In this paper,we were optimized scan modes and scan protocols in kidney CTA,liver enhancement CT scanning,CT pulmonary angiography and low concentration of contrast media in CT portal venography,and successfully applied these scan mode and scan protocols to clinical.Concrete research content is as follows:1)A comparison of the image quality and radiation dose with routine CT and the latest Gemstone Spectral Imaging combination of different scanning protocols in CT angiography of the kidney.Both the Gemstone Spectral Imaging(GSI)scan mode and the routine CT scan mode are used in clinical practice for kidney CTA examination,and the GSI scan mode allows different scanning protocols depending on the rotation time,scan field of view(SFOV),detector coverage and average mA.In maintaining image quality,is it the lowest in the radiation dose of the scan mode and the scan protocol?Therefore,decreasing the patient's radiation dose from a CTA examination and optimizing the CT scan mode and CT scan protocol while still maintaining image quality has become a focus of clinical radiology practice.For clinical populations in particular,reducing the radiation dose by reducing the tube current or tube voltage is important.Unfortunately,decreasing the tube current can increase the image noise of the acquired images,which might adversely affect the diagnostic confidence.Higher image noise can reduce by using different advanced reconstruction algorithms to maintain low radiation doses.The ASiR algorithm effectively reduces noise and maintains image quality,and it is widely used.ASiR 2.0is the updated version of the ASiR algorithm.In this study,we compared the image quality and radiation dose between the latest GSI combination of different scanning protocols with ASi R 2.0 and the routine CT scan mode for kidney CTA.The results showed that radiation dose reductions for kidney CTA using the latest GSI scan protocol B combination with ASiR 2.0 of up to 46.25%compared with the routine CT scan mode and up to 14.43%compared with GSI scan protocol A in18.5kg/m~2?BMI<34.9kg/m~2.Therefore,the latest GSI scan protocol B combination with ASiR 2.0 for kidney CTA can be suggested for these patients in clinical practice.2)CT enhanced scan in liver by different body mass index using different noise index and iterative reconstruction algorithm:imaging quality and radiation dose.CT enhanced in liver is a frequently performed imaging procedure and there is multiphase scan examination,resulting in considerable radiation doses to the patient population.Consequently,concerns regarding the amount of radiation dose and its risks have also increased.Therefore radiologists should continuously optimize CT scan protocols to reduce the radiation dose while maintaining the diagnostic image quality.3D Smart mA techniques for CT scanning has been called one of the most important technological developments for CT radiation dose reduction,and it is able to get good image quality while reducing the tube current.In one implementation of3D Smart mA,the Noise Index(NI)value can be used to control the output of the tube current,so the NI is used in an indirect representation of image quality.The higher NI set for the CT scanner can decrease the amount of radiation dose for patients and lower the NI can increase the amount of radiation dose to patients.Optimal NI set in different organs,CT enhanced scan phase and Body Mass Index(BMI)makes it possible to achieve clinically acceptable images at the lowest radiation dose to patients.However,image noise is inversely proportional to the square root of the radiation dose,so that with the reduced radiation dose,the images have a higher noise level than with conventional radiation dose and must be restrained and reduced.In this study,we evaluated the image quality and radiation dose of different NI settings(11,13,15,and 17)for liver enhanced CT examination with the ASiR technique,and used the optimal NI value of different BMI for liver CT enhanced scanning in different scan phase so,and optimize the best scan NI values for liver enhanced CT scan in lowest radiation dose and maintain image quality.The results showed that patients with 18.5kg/m~2?BMI<29.9kg/m~2can be scanned at NI 15in the late arterial phase,and at NI 17 in the portal venous and equilibrium phases,ED were significantly lower in the NI=15 and N=17 subgroups than in NI=11.Specifically,ED of NI=15 and NI=17 was reduced by 51.69%and 57.01%compared to NI=11,respectively.Patients with a BMI of 29.9–34.9 kg/m~2can be scanned at NI13 in the late arterial phase,and at NI 15 in the portal venous and equilibrium phases,ED were significantly lower in the NI=13 and N=15 subgroups than in NI=11.Specifically,ED of NI=13 and NI=15 was reduced by 29.27%and 50.75%compared to NI=11,respectively.3)A comparison of the image quality and radiation dose using 100-kVp combination of different noise index with low concentration contrast media and120-kVp in CT pulmonary angiography.CT pulmonary angiography(CTPA)has become the radiological examination of choice for pulmonary embolism(PE)in the clinic.It has a high sensitivity(94-100%)and specificity(89-100%)for the diagnosis of acute PE.However,the amount of radiation exposure to the patient population of CTPA and its risks has also drawn radiologists attention.Therefore,decreasing the patient's radiation dose and iodine intake from a CTPA examination and optimizing the CT scan parameters and protocols while still maintaining image quality has become a focus of clinical radiology practice.For clinical populations in particular,it is important to reduce the radiation dose by reducing the tube potential and tube current.Furthermore,reductions in tube potential have the added benefit of improving intravascular image quality on CT scans obtained with iodine contrast material.Unfortunately,reducing the tube voltage can increase the hardening artifacts by iodine contrast media reducing the tube current can increase the image noise of the acquired images,which might adversely affect the diagnostic confidence.However,higher image noise can be reduced by using different advanced reconstruction algorithms to maintain low radiation doses.The ASi R algorithm effectively reduces noise and maintains image quality,and it is widely used.ASiR 2.0 is the updated version of the ASiR algorithm.In this study,we compared the image quality and radiation dose between100-kVp CT scan protocols in combination of different NIs(NI=30,35 and 40)with low concentration contrast media(320mgI/ml)and 120-kVp CT scan protocol in combination of NI=25 with conventional concentration contrast media(370mgI/ml)for CTPA,and optimize the best scan protocol and parameter for CTPA in lowest radiation dose and maintain image quality.The results demonstrated that 100-kVp with NI=40 combined with concentration contrast medium of 320 mgI/ml allows an average of 48.00%radiation dose reduction and an average of 15.40%total iodine intake compared with the 120-kVp with NI=25 combined with concentration contrast medium of 370 mgI/ml for CTPA at 18.5 kg/m~2?BMI<34.9 kg/m~2,and there was no different between the two scan protocols with image quality.4)The application of low concentration of contrast media with spectral CT imaging in CT portal venography.With the wide application of iodine contrast media in clinical,the side effects of its use are a source of increasing concern.CT portal venography(CTPV)has become the main imaging examination method for the assessment of patients with portal diseases.A high concentration of iodine contrast media is required to maintain the concentration of iodine in the portal vein when the CTPV is performed,but this high concentration in the contrast media can increase the incidence of contrast induced nephropathy(CIN).Therefore,decreasing the patient's total iodine intake and concentration of the contrast media from a CTPV examination while still maintaining image quality has become a focus of clinical radiology practice.Recently,spectral CT has generated images from 40 keV to 140 keV single-source energy CT with fast tube voltage switching at 0.25s,which can feasibly display systemic veins from the best contrast-to-noise ratio(CNR)curve using the Alvarez two element analysis process.The purpose of this study was to evaluate the effect of spectral CT on reducing the concentration of the contrast media and improving CTPV image quality,and to select the optimal single energy level to provide the best CNR for displaying portal veins.The results demonstrated that Monochromatic images at50-53 keV demonstrated the best CNR for both the portal vein and erector spinae muscle.Total iodine intake at 296 mgI/ml was 21.47%lower than that at 370 mgI/ml at 18.5kg/m~2?BMI<34.9/kg/m~2.