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Objective To investigate the clinical feasibility of using gemstone spectral image (GSI)technique to reduce the individual dose of contrast agent in performing lower extremity angiography.Methods Among the consecutive 75 patients receiving lower extremity CTA examination,60 patients were enrolled in this study.According to the scanning method and contrast dosage,the 60 patients were prospectively and randomly divided into the conventional CT routine-dose group (n=20),GSI routine-dose group (n=20) and GSI low-dose group (n=20).In the conventional CT routine-dose group and GSI routine-dose group,the dosage of contrast medium was 2 ml/kg and the injection rate was 3.5 ml/s.Scanning with 120 kVp and reconstruction with filter back projection (FBP) technology were used in the conventional CT routine-dose group,while scanning with spectrum mode and reconstruction with 50％ adaptive statistical iterative reconstruction (ASiR) technology were used in the GSI routine-dose group.In the GSI low-dose group,the dosage of contrast medium and the injection rate were 1.6 ml/kg and 2.8 ml/s respectively,and scanning with spectrum mode and reconstruction with 50％ ASiR technology were adopted.The target vessel CT values of three sets of images were determined,the contrast-to-noise ratio (CNR),the background noise (BN),the dose length product (DLP),the effective dose (ED),the iodine intake dose and the injection rate were calculated and compared between each other among the three groups.Single factor variance analysis and Bonferroni correction method were used to statistically analyze the results.By using Kruskal-Wallis test,the subjective scores of three sets of images were compared between each other among the three groups.Results According to exclusion criteria,60 patients were finally enrolled in this study.The images of GSI routine-dose group had the best CT value,CNR and BN (P＜0.01),but there was no statistically significant difference in BN between GSI routine-dose group and GSI low-dose group (P＞0.05).Both the CT value and CNR,except anterior tibial artery (P=0.162 and P=0.376 respectivcly),in the GSI low-dose group were higher than those in the conventional CT routine-dose group (P＜0.05).The ED values of both GSI groups were lower than that of the conventional CT routine-dose group (P＜0.01),although no statistically significant difference in ED value existed between the two GSI groups (P＞0.05).The iodine intake dose and injection rate of the GSI lowdose group were strikingly lower than those of the conventional CT routine-dose group and the GSI low-dose group (both P＜0.01).The subjective scores of three sets of images evaluated by two physicians were 82,95,90 points and 80,96,89 points respectively,the differences were statistically significant (H=14.954,P＜0.01;H=17.726,P＜0.01).GSI routine-dose group had the best image quality,and the image quality of GSI low-dose group was superior to that of conventional CT routine-dose group (P＜0.05).Conclusion Compared with conventional spiral CT scanning,gemstone optimal monochromatic imaging technique can obtain more optimal CNR and image quality,meanwhile,the radiation dose can be remarkably reduced while the imaging quality of lower extremity angiography can meet the requirements of making clinical diagnosis,moreover,individual intake of iodine can be reduced.
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Objective To investigate the value of quantitative analysis of spectrum CT in the differential diagnosis of lung cancer and tuberculosis in unenhanced phase.Methods Data of 51 patients with solitary pulmonary nodules or masses confirmed by pathology who underwent chest unenhanced spectrum CT were retrospectively analyzed.There were 36 cases of peripheral lung cancer (lung cancer group) and 15 cases of tuberculosis (tuberculosis group).The differences of 40～ 140 keV single energy CT value,shape and slope of energy spectrum attenuation curve,different base material of concentration values and effective atomic number (Eff-Z) between the two groups were compared.Results The single energy CT values of 40～70 keV in lung cancer group were higher than those in tuberculosis group (all P＜0.05),while no significant difference of the single energy CT values of 80～140 keV were found in both two groups (all P＞0.05).The shape of energy spectrum attenuation curve of lung cancer group was fast express reduction (36/36,100％).The energy spectrum attenuation curve of tuberculosis group showed walked straightly (11/15,73.33％) and back up type (4/15,26.67％).The slope of the energy spectrum attenuation curve in lung cancer group (K40～ 65 key,K65～90 kev,K90～140 kev)were higher than those in tuberculosis group (all P＜0.01).The calcium (water) concentration of lung cancer group was higher than that of tuberculosis group (P＜0.01),while the lipid (water) concentration of lung cancer group was lower than that of tuberculosis group (P＜0.01).The water (calcium) concentration in both groups was not statistically different (P=0.10).The Eff-Z of lung cancer group was higher than that of the tuberculosis group (P＜0.01).Conclusion The peripheral lung cancer and the tuberculosis have different energy spectrum CT quantitative parameters in unenhanced phase,which can provide valuable informations for diagnosis.
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Objective To investigate the value of CT spectral imaging in differential diagnosis of atypical pheochromocytoma and adrenal adenoma.Methods The energy spectrum CT data of 13 cases of atypical pheochromocytoma and 15 cases of adrenal cortical adenoma confirmed by surgery pathology were retrospectively analyzed.All images processed by spectrum software.The CT value of different energy levels (40-140 keV) in arterial,venous and delayed phase,energy spectrum curve and spectrum curve type,base material of concentration (water-iodine,grease-iodine,blood-iodine) were obtained,and the CT value of different energy were standardize in the same period.Data were compared with samples t test.Results For arterial phase,the standardization CT values of pheochromocytoma on monochromatic images of 40 keV,70 keV to 140 keV had statistical difference with those of adenoma (all P＜0.05).For venous phase,the standardization CT values of pheochromocytoma on monochromatic images of 70 keV to 140 keV had statistical difference with those of adenoma (all P＜0.05).For delayed phase,the standardization CT values of the two tumors on monochromatic image of 40 keV to 140 keV had significant difference (all P＜0.05).Both the energy spectrum of the three periods of type curve was falling,pheochromocytoma always located above compared with adenoma.The standardization concentration of base materials including water (iodine),fat (iodine) and blood (iodine) of pheochromocytoma were higher than those of adenoma in three phases (all P＜0.001).The standardization concentration of base materials including iodine (water),iodine (fat) and iodine (blood) had no significant difference in three phases between pheochromocytoma and adenoma (all P＞ 0.05).Conclusion Atypical pheochromocytoma and adrenal adenoma have different spectral curve and spectrum characteristics of the material content.Spectral CT imaging provides a method of multiple parameters to identify atypical adrenal pheochromocytoma and adenoma.
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Objective To compare the displayed inner diameter of coronary stent by high definition(HD)and gem?stone spectral imaging(GSI)using dynamic cardiac and coronary artery phantom. Methods Five different types of coro?nary stents(internal diameter, 3.10 mm±0.55 mm;strut thickness, 0.12 mm±0.04 mm)were placed into a pulsating cardiac phantom(ALPHA 1-VT PC, Fuyo Corporation, Japan). The stent phantom was scanned by 3 systems, gemstone spectral im?aging(GSI), spiral scan(S)and HD. All the spectral imaging data were analyzed using GSI viewer to reconstruct the VMS (monochromic spectral) images(60-140 keV). Image noise(N), signal-to-noise ratio(SNR), contrast-to-noise ratio(CNR) and inner diameter were compared between images acquired through these 3 systems. Results SNRs in images of S and HD were higher than that of GSI(P0.05). The visible diameter(%)measurements of HD(0.85 ± 0.06)was significant higher than that of the other 2 scan systems and most close to the width of those stent’s actual size.(GSI:0.40±0.16, 0.48±0.13, 0.50±0.14, 0.51±0.13, 0.45±0.05,0.52±0.13, 0.53±0.13, 0.53±0.13, 0.53±0.13, S:0.53±0.14, P<0.05). Conclusion There was no significant dif?ferences in image quality among the images acquired by these 3 systems when the heart rate was set to 60 beats per min. Comparing to GSI and S, HD can produce best represent images to the known inner diameter of coronary stent.
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Objective To explore a quality assurance testing method for gemstone spectral imaging (GSI)computed tomography. Methods A phantom prototype made of 9 bottles of pure water mixed with Iopamidol (300 mg I/mL)at different Iodine concentra-tions was scanned using the GSI mode under a routine head protocol on a GE Discovery CT750 HD scanner.Then the images were post-processed on a GE AW4.6 workstation.Results Based on the effective atomic number histogram,water & Iodine scatterplot and spectral HU curve,the Iodine solution concentrations of the phantom were not only differentiated but quantified.Conclusion It is feasible to test the material decomposition capability of GSI with the phantom prototype.
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OBJECTIVE: To optimize the dose of contrast agent and the level of energy for dual-energy computed tomography (DECT) arthrography of the shoulder joint and to evaluate the benefits of the optimized imaging protocol. MATERIALS AND METHODS: Dual-energy scans with monochromatic spectral imaging mode and conventional single energy scans were performed on a shoulder phantom with 10 concentrations from 0 to 210 mg/mL of iodinated contrast medium at intervals of 15 or 30 mg/mL. Image noise, tissue contrast, and beam hardening artifacts were assessed to determine the optimum dose of contrast agent and the level of monochromatic energy for DECT shoulder arthrography in terms of the lowest image noise and the least beam hardening artifacts while good tissue contrast was maintained. Material decomposition (MD) imaging for bone-iodine differentiation was qualitatively assessed. The optimized protocol was applied and evaluated in 23 patients. RESULTS: The optimal contrast dose and energy level were determined by the phantom study at 60 mg/mL and 72 keV, respectively. This optimized protocol for human study reduced the image noise and the beam-hardening artifacts by 35.9% and 44.5%, respectively. Bone-iodine differentiation by MD imaging was not affected by the iodine concentration or level of energy. CONCLUSION: Dual-energy scan with monochromatic spectral imaging mode results in reduced image noise and beam hardening artifacts.
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Female , Humans , Male , Middle Aged , Analysis of Variance , Artifacts , Contrast Media , Phantoms, Imaging , Shoulder Joint/pathology , Signal-To-Noise Ratio , Tomography, X-Ray ComputedABSTRACT
Objective To evaluate the clinical value of gemstone spectral imaging (GSI) in preliminary assessment of esophageal carcinoma pathology features.Methods 58 patients were analyzed which were diagnosed with histological pathology as esophageal carcinoma underwent GSI enhanced scans before surgery.The iodine concentrations (IC) in the lesions were measured on the iodine-water based material-decomposition images.The results of IC value were evaluated retrospectively with different pathological grading,locations and pathological morphology according to the final pathologic findings.Results 52 cases patients were squamous cell carcinoma and 6 patients were adenocarcinoma.The IC values were (14.75±4.24) mg/ml and (12.86±5.09) mg/ml.The IC value between the two different pathological types had not statistically difference (P =0.35).The IC of different pathological grading:Well differentiation was (20.08± 4.66)mg/ml,n =19.Medium was (14.13±3.39) mg/ml,n =25.Poor was(11.73±3.21) mg/ml,n =14.The IC values between pathological grading had significant difference(P =0.00).There were four different pathological morphology including m edullar (n =16),m ushroom type (n =21),ulcer (n =13) and narrow type (n =8).Their IC values respectively were (16.34±2.56) mg/ml,(18.70±3.03) mg/ml,(14.31±4.60) mg/ml and (11.18±2.09) mg/ml.The IC value between mushroom and narrow type had statistical difference (P =0.04).The Other types had no statistically difference (P =0.19).Conclusions The results of this study demonstrate that GSI has a certain ability of pathologic stage of esophageal cancer.The GSI has a certain clinical value in guiding treatment and judging prognosis of esophageal carcinoma.
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Purpose To implement lower artery angiography in patients with peripheral arterial occlusive disease, and to investigate the feasibility of lower extremity gemstone spectral CT angiography in improving image quality.Materials and Methods Forty-eight patients suspected with lower extremity arterial occlusive diseases were randomly divided into research group and control group. Research group (24 cases) were carried out gemstone spectral CT angiography (CTA) scan and control group (24 cases) were scanned with multi-slice spiral CT (CTA). The CT value of the common iliac artery, popliteal artery and its branches was measured and contrast to noise ratio (CNR) were calculated in both groups. The images were evaluated independently by 2 senior physicians based on a 5-level evaluation standard.Results The CT value of common iliac artery, popliteal artery, anterior tibial artery and the CNR in research group were all higher than those in control group (t=8.7, 7.9, 12.6 and 17.2,P<0.01), but the background noise was lower than that in control group (t=1.5,P<0.01). The scores of two image quality accessed by physician 1 and 2 were 110:90 and 111:93 respectively with statistical difference (Z=-7.6 and-8.0, P<0.01).Conclusion The image obtained by gemstone spectral CT optimal single energy image technique is much better than that by conventional multi-slice spiral CT in lower extremity angiography.
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The primary gastric lymphoma and infiltrating gastric carcinoma have similar imaging performance.Therefore,it has been longely regarded as medical imaging difficulty to diagnostically differentiate between them.With the rapid development of various imaging techniques and imaging software,they have been widely used in differentiating between these two diseases.This article reviews the current status and progress of imaging studies in differentiation of primay gastric lymphoma and invasive gastric cancer.
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ObjectiveTo measure the iodine content of normal thyroid and the sternocleidomastoid muscle with gemstone spectral imaging (GSI),in order to offer diagnostic reference for iodine excess or iodine deficiency disorders.MethodsA total of 226 cases of patients with suspected neck or cervical disease underwent GSI of the neck,the thyroid and the sternocleidomastoid muscle.One hundred and nineteen cases were male and 107 female,aged 18 to 77 years,average age(46 ± 17) years.Data were transmitted to AW 4.4 workstation and processed using GSI Viewer software to obtain the best contrast-to-noise ratio(CNR) of thyroid to sternocleidomastoid muscle and corresponding singe-energy images.Iodine content of left and right thyroid lobes and both sides of sternocleidomastoid muscle as well as iodine content ratio of thyroid to sternocleidomastoid muscle were calculated in the iodine-based images.ResultsTotal iodine content of the left and the right lobes of the thyroid was (1.5233 ±0.4318)mg/cm3,of the left lobe was (1.5230 ± 0.4271 )mg/cm3,of the right lobe was (1.5236 ± 0.4365 )mg/cm3,there was no significant difference statistically between the two(t =0.0084,P ＞ 0.05).The iodine content of the male was (1.6395 ± 0.4105)mg/cm3,and of the female was (1.4238 ± 0.3832)mg/cm3,there was statistically a significant difference between the two(t =3.4743,P ＜ 0.01 ).Iodine content ratio of thyroid to sternocleidomastoid muscle was 96.6271 ± 33.2442,the ratio in male was 94.6250 ± 37.3621 and in female was 98.0000 ± 29.0737,there was no statistical difference between the two(t =0.3817,P ＞ 0.05).The iodine content of thyroid decreased gradually with age,the difference between groups was statistically significant(F =9.66,P ＜ 0.01 ).The iodine content in ＜ 40 age group[(1.7256 ± 0.4631)mg/cm3] was higher than that in 40 - 60 age group[(1.4517 ±0.3643)mg/cm3] and ＞ 60 age group [(1.4368 ± 0.3465)mg/cm3; q =5.6195,5.4158,all P ＜ 0.01).Conclusions It is easy to calculate thyroid iodine content with gemstone spectral imaging,which can reflect the iodine level of our body,and is helpful for the diagnosis of iodine excess or iodine deficiency disorders.