Objective To observe the imaging findings of congenital megaureter in order to enhance the understanding of this disease. Methods Image data of 5 patients with congenital megaureter and 2 misdiagnosed patients were a...Objective To observe the imaging findings of congenital megaureter in order to enhance the understanding of this disease. Methods Image data of 5 patients with congenital megaureter and 2 misdiagnosed patients were analyzed, and image findings of congenital megaureter were summarized. Elscint Prestig 2.0T superconductive magnetic resonance urography （MRLI） with conventional sequence （spin-echo, T 1W1560 ms/16 ms; fast spin-echo, T2WI 9600 ms/96 ms） was performed. Raw data were acquired with fast spin-echo sequence from heavy T2-weighted image （9600 ms/120 ms）. Post-processing method of MRH was the maximum in- tensity projection with three-dimensional reconstruction in the workstation. Intravenous pyelography （IVP） was conducted, in which X-ray films were taken 7 minutes, 15 minutes, and 30 minutes after injecting contrast agent, except that in 2 patients the films were taken delayed at 60 and 90 minutes. X-ray retrograde pyelography was performed on 2 patients, successful in one but failed in the other. Results The dilated ureter showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images in conventional MRI. The mass wall was intact, uniform in thickness, and showing hy- pointensity on Tl-weighted and T2-weighted images. The MRH images showed a retroperitoneal mass appearing as an elongated tubular cystic structure spreading from kidney to bladder. MRLI also revealed dilated calices and renal pelvis, pelviureteric obstruction, and renal duplication. The main signs of congenital megaureter in X-urography was significant dilatation of ureter, or normal renal pelvis with ureter dilatation, hydronephrosis, deformity, and displacement. Conclusions MRH with X-urography could visualize the characteristics of congenital megaureter, including the dilation of renal pelvis and ureter, calculi, urinary tract duplication, and stenosis location. The two techniques can complement each other in disease diagnosis and provide more detailed information for preoperative treatment.展开更多
To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. Methods Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensa...To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. Methods Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice col-limation 16 mm×1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm×0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed. Results Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluationof image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the sec-ond class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensi-tivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% resp-ectively. Conclusion As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.展开更多
X-ray computed tomography(CT) has been widely used as a powerful diagnostic tool in clinics because it can provide high-resolution 3D tomography of the anatomic structure based on the distinctive X-ray absorptions bet...X-ray computed tomography(CT) has been widely used as a powerful diagnostic tool in clinics because it can provide high-resolution 3D tomography of the anatomic structure based on the distinctive X-ray absorptions between different tissues. Currently, CT contrast agents are mainly small iodinated molecules, which suffer from drawbacks such as short blood- retention time, nonspecific in vivo biodistribution, and renal toxicity. Utilization of nanoparticles as potential CT contrast agents to overcome the aforementioned issues has advanced rapidly. In this mini review, we introduce current research efforts in the development of nanoparticulate CT contrast agents and discuss the challenges for additional breakthroughs in this field.展开更多
Aiming at improving the sensitivity and accu- racy 9f diagnosis, the combination of magnetic resonance imaging （MRI） and X-ray computed tomography （CT） in a single probe is in urgent need. Here, we report the deve...Aiming at improving the sensitivity and accu- racy 9f diagnosis, the combination of magnetic resonance imaging （MRI） and X-ray computed tomography （CT） in a single probe is in urgent need. Here, we report the devel- opment of polyacrylic acid （PAA）-capped GdF3 nanoplates （NPs） as novel MRI and CT dual-mode contrast agents （CAs） with high longitudinal relaxivity （rl） and large X-ray attenuation coefficient. Uniform GdF3 rhombic NPs were fabricated by controlling reaction conditions and intro- ducing dopants. The average size of GdF3 NPs is （10.6 ：k 1.1） nm in long diagonal, （7.0 -t- 0.8） nm in short diagonal, and （4.2 -4- 1.2） nm in thickness. Ligand-exchange treat- ment was performed to render the NPs water-dispersible. The rl of PAA-capped GdF3 NPs （15.8 L/（mmol s）） is four times higher than that of clinically used Gd-DTPA. We suppose that the high r~ value originates from the con- struction of two-dimensional （2D） nanostructures, which endows nanocrystals with larger surface areas and longer rotational correlation time than those of sphere nanostruc- tures with the same volume. The CT contrast enhancement ability of PAA-capped GdF3 NPs was evaluated in com- parison with clinically used Iohexol. The above results suggest that the PAA-capped GdF3 NPs could serve as CAs for MRI and CT dual-mode imaging.展开更多
文摘Objective To observe the imaging findings of congenital megaureter in order to enhance the understanding of this disease. Methods Image data of 5 patients with congenital megaureter and 2 misdiagnosed patients were analyzed, and image findings of congenital megaureter were summarized. Elscint Prestig 2.0T superconductive magnetic resonance urography （MRLI） with conventional sequence （spin-echo, T 1W1560 ms/16 ms; fast spin-echo, T2WI 9600 ms/96 ms） was performed. Raw data were acquired with fast spin-echo sequence from heavy T2-weighted image （9600 ms/120 ms）. Post-processing method of MRH was the maximum in- tensity projection with three-dimensional reconstruction in the workstation. Intravenous pyelography （IVP） was conducted, in which X-ray films were taken 7 minutes, 15 minutes, and 30 minutes after injecting contrast agent, except that in 2 patients the films were taken delayed at 60 and 90 minutes. X-ray retrograde pyelography was performed on 2 patients, successful in one but failed in the other. Results The dilated ureter showed hypointensity on T1-weighted images and hyperintensity on T2-weighted images in conventional MRI. The mass wall was intact, uniform in thickness, and showing hy- pointensity on Tl-weighted and T2-weighted images. The MRH images showed a retroperitoneal mass appearing as an elongated tubular cystic structure spreading from kidney to bladder. MRLI also revealed dilated calices and renal pelvis, pelviureteric obstruction, and renal duplication. The main signs of congenital megaureter in X-urography was significant dilatation of ureter, or normal renal pelvis with ureter dilatation, hydronephrosis, deformity, and displacement. Conclusions MRH with X-urography could visualize the characteristics of congenital megaureter, including the dilation of renal pelvis and ureter, calculi, urinary tract duplication, and stenosis location. The two techniques can complement each other in disease diagnosis and provide more detailed information for preoperative treatment.
文摘To evaluate the value of 16-slice spiral CT in the demonstration of coronary artery and in the diagnose of coronary artery stenosis. Methods Plain and enhanced CT scans were performed with a 16-slice CT scanner (Sensation 16, Siemens, Germany) in 230 patients with suspected coronary heart disease (CHD). Parameters of the plain scan were: 120 kV, 133 mA, slice col-limation 16 mm×1.5 mm, rotation time 0.42 seconds, increment 1.5 mm, and slice width 3 mm. Parameters of the enhanced scan were: 120 kV, 500 mA, slice collimation 16 mm×0.75 mm, rotation time 0.42 seconds, increment 0.5 mm, and slice width 1 mm. Enhanced CT scan was performed with a rapid intravenous injection of 100 mL iothalamate meglumine (Ultravist) (370 mgI/mL) or Omnipaque (350 mgI/mL) and 30 mL 0.9% NaCl chaser bolus at a flow rate of 3.5 mL/s. Calcium scoring with plain scan images and two and three dimensional reconstruction with enhanced scan images were made in all cases, among which 30 cases underwent conventional coronary angiography. Demonstration of coronary arteries and their stenosis were evaluated and the factors that might influence the image quality were analyzed. Results Coronary calcium scores were calculated and coronary artery was demonstrated in our study. In the evaluationof image quality with volume rendering technique (VRT) images, 78.3% of the images were of the first class, 12.2% the sec-ond class, and 9.6% the third class. Multi-planar reconstruction (MPR) and maximal intensity projection (MIP) were better than VRT in the demonstration of small branches. The image quality was related to the heart rate, with or without arrhythmia, and breath-hold ability of patients. Comparative study of the stenosis of coronary arteries in 30 cases showed that the sensi-tivity and specificity of 16-slice coronary CT angiography (CTA) to diagnose significant stenosis were 95.8% and 94.8% resp-ectively. Conclusion As a non-invasive and quick method, 16-slice coronary CTA is sensitive and specific to diagnose the stenosis of coronary arteries and can be used as a screening method in the diagnosis of CHD.
基金supported by the Jilin Province Youth Foundation(20130522131JH)the National Natural Science Foundation of China(21125521,21075117)the Hundred Talents Project of the Chinese Academy of Science
文摘X-ray computed tomography(CT) has been widely used as a powerful diagnostic tool in clinics because it can provide high-resolution 3D tomography of the anatomic structure based on the distinctive X-ray absorptions between different tissues. Currently, CT contrast agents are mainly small iodinated molecules, which suffer from drawbacks such as short blood- retention time, nonspecific in vivo biodistribution, and renal toxicity. Utilization of nanoparticles as potential CT contrast agents to overcome the aforementioned issues has advanced rapidly. In this mini review, we introduce current research efforts in the development of nanoparticulate CT contrast agents and discuss the challenges for additional breakthroughs in this field.
基金This work was supported by the National Natural Science Foundation of China （21425101, 21371011, 21331001） and the National Basic Research Program of China （2014CB643800）.
文摘Aiming at improving the sensitivity and accu- racy 9f diagnosis, the combination of magnetic resonance imaging （MRI） and X-ray computed tomography （CT） in a single probe is in urgent need. Here, we report the devel- opment of polyacrylic acid （PAA）-capped GdF3 nanoplates （NPs） as novel MRI and CT dual-mode contrast agents （CAs） with high longitudinal relaxivity （rl） and large X-ray attenuation coefficient. Uniform GdF3 rhombic NPs were fabricated by controlling reaction conditions and intro- ducing dopants. The average size of GdF3 NPs is （10.6 ：k 1.1） nm in long diagonal, （7.0 -t- 0.8） nm in short diagonal, and （4.2 -4- 1.2） nm in thickness. Ligand-exchange treat- ment was performed to render the NPs water-dispersible. The rl of PAA-capped GdF3 NPs （15.8 L/（mmol s）） is four times higher than that of clinically used Gd-DTPA. We suppose that the high r~ value originates from the con- struction of two-dimensional （2D） nanostructures, which endows nanocrystals with larger surface areas and longer rotational correlation time than those of sphere nanostruc- tures with the same volume. The CT contrast enhancement ability of PAA-capped GdF3 NPs was evaluated in com- parison with clinically used Iohexol. The above results suggest that the PAA-capped GdF3 NPs could serve as CAs for MRI and CT dual-mode imaging.
