Dual-source dual-energy CT for the differentiation of urinary stone composition: preliminary study / 中华放射学杂志

Objective To evaluate dual-source dual-energy CT(DSCT) for the differentiation of urinary stone composition in vitro. Methods Ninety-seven urinary stones were obtained by endoscopic lithotripsy and scanned using dual-source dual-energy CT. The stones were divided into six groups according to infrared spectroscopy stone analysis: uric acid ( UA ) stones ( n = 10 ), cystine stones ( n = 5 ), struvite stones( n = 6), calcium oxalate ( CaOx ) stones ( n = 22 ), mixed UA stones ( n=7 ) and mixed calcium stones(n=47). Hounsfield units (HU) of each stone were recorded for the 80 kV and the 140 kV datasets by hand-drawing method. HU difference, HU ratio and dual energy index ( DEI ) were calculated and compared among the stone groups with one-way ANOVA. Using dual energy software to determine the composition of all stones, results were compared to infrared spectroscopy analysis. Results There were statistical differences in HU difference [(-17±13), (229±34),(309 ±45), (512 ±97), (201±64)and (530±71) HU respectively], in HU ratio (0.96±0.03, 1.34 ±0.04, 1.41 ±0.03, 1.47 ±0.03,1.30±0.07, and 1.49 ±0.03 respectively), and DEI( -0.006 ±0.004, 0.064 ±0.007, 0.080 ±0. 007, 0. 108±0.011 ,0. 055 ±0.014 and 0. 112 ±0.008 respectively ) among different stone groups(F=124. 894,407.028, 322. 864 respectively, P ＜0. 01 ). There were statistical differences in HU difference,HU ratio and DE1 between UA stones and the other groups( P ＜ 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between CaOx or mixed calcium stones and the other four groups (P＜0. 01 ). There was statistical difference in HU ratio between cystine and struvite stones ( P ＜ 0. 01 ). There were statistical differences in HU difference, HU ratio and DEI between struvite and mixed UA stones (P＜0. 05 ). Dual energy software correctly characterized 10 UA stones, 4 cystine stones, 22 CaOx stones and 6 mixed UA stones. Two struvite stones were considered to contain cystine. One cystine stone, 1 mixed UA stone, 4 struvite stones and 47 mixed calcium stones were considered to contain oxalate. Conclusions DSCT has the ability to differentiate urinary stone composition in vitro. With dual energy software, the UA, cystine and mixed UA stones can be differentiated from other types of stones.

Choice of optimal phase for liver angiography and multi-phase scanning with multi-slice spiral CT / 中华放射学杂志

Objective To evaluate the effieaey of test bolus technique with multi-slice spiral CT (MSCT) for determining the optimal scan delay time in CT Hepatic artery (HA)-portal vein (PV) angiography and multi-phase scanning.Methods MSCT liver angiography and multi-phase scanning were performed in 187 patients divided randomly into two groups.In group A (n =59),the scan delay time was set according to the subjective experiences of operators; in group B (n=128),the scan delay time was determined by test bolus technique.Abdominal aorta and superior mesenteric,vein were selected as target blood vessels,and 50 HU was set as enhancement threshold value.20 ml contrast agent was injected intravenously and time-density curve of target blood vessels were obtained,then HA-PV scanning delay time were calculated respectively.The quality of CTA images obtained by using these 2 methods were compared and statistically analysed using Chi-square criterion.Resuits For hepatic artery phase,the images of group A are:excellent in 34(58%),good in 17(29%),and poor in 8 (13%),while those of group B are excellent in 128( 100%),good in 0(0%),and poor in 0(0%).For portal vein phase,the images of group Aare:excellent in 23(39%),good in 27(46%),and poor in 9(15%),while those of group B are excellent in 96 (75%),good in 28 (22%),and poor in 4 (3%) respectively.There was statistically significant difference between the ratios of image quality in group A and group B (X2=14.97,9.18,P < 0.05).Conclusion Accurate scan delay time was best determined by using test bolus technique,which can improve the image quality of liver angingraphy and multi-phase scanning.

Evaluating non-invasive medical imaging for diagnosis of carotid artery stenosis with ischemic cerebrovascular disease / 中华医学杂志(英文版)

<p><b>OBJECTIVES</b>To assess the value of non-invasive medical imaging for diagnosis of carotid artery stenosis and to study the relationship between carotid stenosis and brain infarction.</p><p><b>METHODS</b>Thirty-one patients with a total of 62 carotid arteries were studied using Doppler ultrasound (DUS) and magnetic resonance angiography (MRA). Eleven of the 31 patients were studied using CT angiography (CTA). CT and MRI of the brain were also done in all patients. The imaging results in 5 patients were compared with those of digital subtraction angiography (DSA). Eight patients with severe stenosis received carotid endarterectomy. The comparisons between the imaging results and pathological data were conducted in 2 patients.</p><p><b>RESULTS</b>Of the 62 carotid arteries, mild stenosis was seen in 11, moderate in 14, severe in 21, obstructed in 4 and normal in 12. In 25 patients with severe stenosis or occlusion of carotid arteries, there were a total of 35 focal or multifocal infarcts on the ipsilateral cerebral hemisphere, and 15 infarcts on the contrary side. Compared with the results of the operations, DUS correctly diagnosed 6 stenoses, while MRA identified 7 correctly and CTA 8. Agreement on location of stenosis as performed by endarterectomy, DUS, MRA and CTA occurred in all patients. Histologically, areas of calcification and fibrousness were related to high densities on CTA, strong echoes on DUS, and low signal intensities on MRA. Relatively large amounts of necrotic material and foam cells filled with lipolytic materials on the intimal surface of arteries were observed during pathologically, corresponding to low and iso-densities on CTA, low echoes on DUS, and inhomogeneous signal intensities on MRA.</p><p><b>CONCLUSIONS</b>A strong link exists between carotid stenosis and brain infarction. The combined use of DUS, MRA and CTA can improve diagnostic accuracy for the assessment of carotid artery stenosis, as well as assist in ascertaining the nature of the plaque.</p>

Evaluation of magnetic resonance imaging in adenomyosis / 解放军医学杂志

Objective To evaluate the MR manifestation to provide guidance for the clinical diagnosis of adenomyosis.Methods The MR images of 43 cases of adenomyosis which were proved by operation and pathology were reviewed.Results Among the 43 cases of adenomyosis,26 cases were of diffuse adenomyosis and 17 of focal adenomyosis.Leiomyoma(21 cases),intra-pelvic cavity chocolate cyst (17 cases)and ovarian cyst(15 cases)were concurrently found in this group of patients.The MRI of diffuse adenomyosis demonstrated an enlarged uterus and widened uterine junction zone with ill-defined margin between junction zone and myometrium.The adenomyosis lesions showed iso-signal intensity on T_1 weighted images and iso-signal or slight low signal intensity on T_2 weighted images with scattered hyper- intense foci.The uterine cavities were irregularly narrowed due to compression of thickening junction zone.The lesions showed mild con- trast enhancement on contrast-enhanced MR images.The MRI of focal adenomyosis displayed localized myometrial masses with ill-defined margin with widening of junction zone.The lesions were round or oval in shape with iso-signal intensity on T_1 weighted images and inho- mogeneous slightly low signal on T_2 weighted images.Multiple scattered hyperintense foci could be found in the mass on the T_2 weighted images.The lesions had mild contrast enhancement on contrast-enhanced MR images.The concurrent leiomyoma,intra-pelvic cavity choc- olate cyst and ovarian cyst were also displayed by MR imaging.Conclusion The widened junction zone is the characteristic change of ade- nomyosis.MRI can demonstrate the types,size and concurrent changes in adenomyosis,and is a useful noninvasive imaging method for the diagnosis of adenomyosis.

Image quality control of MSCT in the evaluation of coronary artery stent / 解放军医学杂志

Objective To study the clinical significance of using MSCT(16 multi slice spiral CT,MSCT)to evaluate the patency of coronary arterial stent,and to explore the factors contributing to the image quality.Methods 32 patients with coronary arterial stent im- plantation received MSCT.The shape and position of the stent and the situation of restenosis were checked with several methods.Of the 32 patients,the results in 7 cases were further verified by X-ray coronary artery angiography.The image qualities were classified in three grades.The influence factors contributing to imaging quality were analyzed.Results The rate of good image quality for MSCT coronary artery angiography was 87.5%(28/32).The rate of good image quality for the patients with heart rate less than 60 was 94.7%,for those with heart rate of 61-70 was 88.9%,and for those with heart rate over 70 was 50.0%,there existed significant differences(X~2=16.354, P

Clinical Evaluation of Spiral CT Pulmonary Angiography in the Diagnosis of Pulmonary Embolism / 实用放射学杂志

Objective To evaluate the clinical application of spiral CT pulmonary angiography(SCTPA) in the diagnosis of pulmonary embolism(PE) and its limitation.Methods 52 cases of PE were analyzed.SCTPA were performed in all cases with slice thickness 3 mm,pitch 1.5~2.0,scanning time 0.8 s,reconstruction thickness 1mm.The reconstructions of SCTPA included MIP,MPR and SSD.Results 2898 pulmonary arteries in 52 cases were observed.The direct manifestations of PE were showed in 927 pulmonary arteries(32.0%) by SCTPA,in which superior segmental and inferior segmental of pulmonary arteries were involved respectively.The indirect manifestations of PE were showed by plain scan in 113 cases.Conclusion SCTPA is a high effective and noninvasive method in the diagnosis of PE especially for the PE of superior segmental.

Helical CT Virtual Cystoscopy:the Clinical Applications and Limitations / 实用放射学杂志

Objective To evaluate the clinical applications and limitations of helical CT virtual cystoscopy (CTVC).Methods CTVC was performed in 36 patients suspected bladder diseases, all cases were confirmed by conventional cystoscopy and pathology. CTVC images were generated from the volumetric data of the excretory phase using helical CT. The results were then compared with the findings of axial images and conventional cystoscopy in a double-blinded manner. Results CTVC could clearly display the normal anatomic structures of bladder, 11 ureteric orifices were visualized at CTVC in 7 of 8 normal bladders. The location, size, numbers, configuration and extension of lesions showed on CTVC were corresponded well with that of conventional cystoscopy. The sensitivity to vesical carcinoma was 94.7%,2 tumors smaller than 5 mm depicted on CTVC images were not seen on the axial images, whereas areas of wall thickening and extravesical invasions were more readily appreciated on axial and MPR images. There was 1 false lesions detected on CTVC images. Conclusion CTVC has proved to be a noninvasive and reliable technique in the detection and diagnosis of bladder lesions, but the optimal evaluation requires adequate bladder filling with contrast medium, and should combine with the interpretation of axial and MPR images.

Helical CT evaluation of the ureteral diseases / 中华放射学杂志

Objective To evaluate the clinical applications of helical CT scans in the ureteral diseases.Methods The precontrast and four-phase postcontrast helical CT scans were performed in 110 patients with ureteral diseases confirmed by clinic and pathology, and the multiplanar reformation (MPR) and three-dimensional reconstruction (3D) images were generated from the volumetric data.The ability of helical CT in detecting and diagnosing the ureteral diseases was investigated.The results were then compared with the findings of the other imaging techniques and surgery.Results Combined with axial and MPR images, the location, size, morphology, extension, and the urinary obstruction of the ureteral diseases could be clearly demonstrated in 97.3% cases, and the curved MPR was useful in directly detecting the lesions.The findings of ureteral lesion on helical CT images corresponded well with that of surgery in 81 cases. 3D reconstruction could produce a three-dimensional image that mimics conventional urography, and was useful in displaying the ureteral lesions from multiple views.Helical CT could compensate for some disadvantages of the other imaging techniques.Conclusion Helical CT, with large scanning area and high resolution, can provide comprehensive information about the ureteral diseases, and the curve MPR has the highest value.

The application of MR and CT angiography in the evaluation of carotid artery stenosis and follow up of carotid endarterectomy / 中华放射学杂志

Objective To estimate the accuracy of MR angiography(MRA) and CT angiography(CTA) in the evaluation of the carotid artery stenosis. Methods Eleven patients were studied with MRA and CTA. The results were compared with DSA, CT virtual endoscopy (CTVE), and Doppler ultrasound (DUS). MRA was performed with 2D and 3D TOF sequences. CTA was postprocessed using MIP and SSD. CTVE was performed using navigator function . Three patients with severe stenosis received carotid endarterectomy. Results There was a total of 22 carotid arteries studied, with 8 mild, 3 moderate, 5 severe stenosis, 1 occlusion, and 5 normal. Agreement on stenosis between CTA and DSA was found in 11 of 12 carotid arteries. Agreement on stenosis between MRA and DSA was found in 9. Plaques were delineated in CTA, CTVE, and confirmed by pathology in 3 cases. Postoperative MRA and CTA proved the release of stenosis. Conclusion MRA and DUS can be used as a screening technique to evaluate carotid artery stenosis and as a convenient follow up modality for post endarterectomy. CTA has a high degree of accuracy for the assessment of carotid artery stenosis compared with DSA, and it could provide information on calcified plaque.

EXPERIMENTAL STUDY OF HELICAL CT COLONOSCOPY / 解放军医学杂志

To explore diagnostic acuity of helical CT colonscopic examination, simulated polyps were reproduced in 10 pig colons and 6 human colons obtained from colon resection. Helical CT colonoscopic scanning with different parameters was performed. The images were evaluated with Nav, Axial+MPR, SSD+Raysum. The diagnostic sensitivity of each method for the detection of simulated colonic polyps were assessed. The results indicated that the image quality of CT colonoscopy was improved with the decrease in collimation and pitch. The optimal angle of the colon lumen to the gantry was 90?. CT colonoscopy was superior to other imaging methods. Therefore, the performance of CTVC has a close relationship with the scanning parameters. The optimal scanning parameters were 5mm collimation, 1 5 pitch, and filling the colon with air. The combination of CTVC with other imaging methods would contribute to improving the diagnostic accuracy for the detection of colonic polyps.

CT and MRI diagnosis of tubo ovarian masses / 中华放射学杂志

Objective To evaluate the diagnostic value of CT and MRI in tubo ovarian masses. Methods CT scan was performed in 67 patients with tubo ovarian masses confirmed by pathology. 19 of them underwent MRI. Results (1) 20 primary malignant ovarian tumors showed cystic, solid or cystic solid masses; papillary projections on cystic wall; pelvic organs and pelvic wall invasion. Chocolate cysts with malignant degene ration exhibited small nodules on thickened cystic wall on CT and MRI.T 1WI was better for revealing the lesions. (2) Of 11 cases of metastasis to tubo ovary, 4 showed peritoneal linear enhancement. (3) There were 9 cystadenomas and 2 adenofibromas , one of the cystadenomas contained fat, two adenofibromas were similar to uterus in density on CT while showing lower signal intensity on MRI (both T 1WI and T 2WI). (4) Three cases of thecoma exhibited cystic or solid masses, solid thecomas revealed granular enhancement.(5) Teratomas were most spicific, one of them was associated with thecoma.(6) Tubo ovarian abscesses and tuberculosis depicted cystic or cystic solid masses.(7) Two cases of tubal pregnancy showed inhomogeneous soft tissue masses, the lower density areas in the centers were clot and organized tissues confirmed by pathology. Conclusion (1) CT and MRI had higher sensitivity but lower specificity for tubo ovarian masses, the diagnosis should be combined with clinical history and patients′ age. (2) Tumors of two different types may coexist and sometimes fat may be present in tumors other than teratoma.