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Objective To investigate the value of third generation dual-source CT in early differential diagnosis of intracranial hemorrhage and iodinated contrast medium after endovascular treatment of acute ischemic stroke (AIS).Methods Totally 78 patients with AIS underwent endovascular treatment were prospectively enrolled.Dual-energy CT (DECT) examination (80 kV/Sn150 kV) of the head was performed after treatment with a third generation dual-source CT scanner.Iodine overlay maps and virtual non-contrast images were post-processed.Taking conventional brain CT images obtained 24 48 h after AIS attack as references,the accuracy,sensitivity,specificity,positive predictive value (PPV) and negative predictive value (NPV) of DECT for identifying hemorrhage were computed respectively.Results Totally 31 patients with 53 foci of intracranial hyper-attenuation were finally enrolled.Among 53 foci,26 were correctly diagnosed as hemorrhage by DECT,23 were correctly diagnosed as iodinated contrast medium,while 1 calcification was misdiagnosed as hemorrhage combined with iodinated contrast medium,3 were misdiagnosed as contrast medium which showed delayed hemorrhagic transformation.The sensitivity,specificity and accuracy of DECT was 89.66％ (26/29),95.83％ (23/24) and 92.45％ (49/53),PPV and NPV was 96.30％ (26/27) and 88.46％ (23/26),respectively.Conclusion The third generation dual-source CT is available in early and accurate diagnosis of hemorrhagic transformation after endovascular treatment of AIS,which can help clinicians to adjust the subsequent treatment strategies in time.
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Objective To evaluate the value of magnetic resonance black-blood thrombus imaging (BTI) of the stage of disease in intracranial venous and sinus thrombosis(CVT).Methods From June 2015 to October 2016,37 patients with CVT diagnosed with routine imaging examinations in Beijing Xuanwu Hospital,Capital Medical University were enrolled prospectively,and they also underwent BTI examination.The patients were randomly divided into either a acute group (≤14 d,n=23) or a chronic group (>15 d,n=14) according to the time from the onset of symptoms to BTI.Signal to noise ratio(SNR) and contrast to noise ratio(CNR) difference between acute and chronic CVT groups were compared.The magnetic resonance venography (MRV) examination was used as a reference to calculate the accuracy of BTI on per-segment level.Results (1) The SNR and CNR of thrombosis in the acute group and chronic group were 206±97 and 94±41,201±96 and 86±40,respectively.There was significant difference between two groups (t=4.9 and 5.0 respectively;all P<0.01).(2) In 37 patients with CVT,the thrombi in 159 cerebral veins and venous sinus segments were detected with MRV.BTI identified the thrombi accurately in 152 vascular segments,and the thrombi in 352 vascular segments were eliminated.The diagnostic sensitivity and specificity were 95.6% (152/159) and 98.0% (352/359) respectively.Conclusion Achieving direct angiography of cerebral venous thrombosis,BTI technique can accurately differentiate acute or chronic thrombus.It has higher accuracy.
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By taking American Penn State University Medical Center as an example, the paper introduced the current American radiology resident education training situation and elaborated the radiology resident rotation system, multiform teaching model and academic research training. Medical education in American sheds light on how to reasonably arrange rotation, mobilize students' subjective initiative and improve scientific research ability, which radiology resident medical education in China can draw lessons from.
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Objective To evaluate the diagnostic accuracy of 3.0 T contrast enhanced (CE) whole heart coronary MRA ( CE MRA ) using 32-channel coils with high acceleration factor. Methods Sixty patients with suspected coronary artery disease who were scheduled for coronary angiography (CAG)underwent CE CMRA at 3.0 T MRI scanner. A 32-channel receiver coil was used for data acquisition. For image acquisition, an ECG-triggered, navigator-gated, inversion-recovery prepared, segmented gradient-echo sequence was used with an acceleration factor of three in the phase-encoding direction using GRAPPA reconstruction. Gd-BOPTA (0.15 mmol/kg body weight) was intravenously administered at a rate of 0. 3 ml/s. The diagnostic accuracy in detecting significant stenoses ( ≥50% of vessel lumen) was evaluated using χ2 test with X-ray angiography as the reference. Results Whole-heart CE CMRA was successfully completed in 56 patients who were scheduled for CAG. The averaged imaging time was ( 6. 0 ± 1.3 ) min.3.0 T CE CMRA using 32 channel coils correctly identified significant CAD in 28 patients and correctly ruled out CAD in 23 patients. The sensitivity and specificity were 93. 3% and 88.5% respectively.Conclusion Combined with dedicated 32-channel coils, 3.0 T CE CMRA allows significant reduction in imaging speed and reduced dose of the contrast agent. These improvements resulted in substantially improved overall accuracy of CE CMRA in detecting coronary artery disease.
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Objective To prospectively assess right ventricular dysfunction and the metergasis before and after therapy of thrombolysis with ECG gated multi-detector spiral computed tomography (MSCT)in patients with acute pulmonary embolism. Methods Triple rule-out ECG gated MSCT examination was performed in 96 consecutive patients suspected of PE. 25 patients with central PE were confirmed. 25 agematched subjects without cardiac and pulmonary disease were recruited as control group. Triple rule-out ECG gated MSCT were performed again to assess cardiac function after therapy of thrombolysis. Dimension ratios for the right ventricle (RV) and left ventricle ( LV), main pulmonary artery and aorta were measured.Furthermore, the RV and LV end-diastolic volumes (EDV), end-systolic volume (ESV) and ejection fraction (EF) were also measured. The mean values were compared with analysis of variance (ANOVA) and Newman-Keuls test before and after thrombolysis. Results The mean values of RVEDV, RVESV, RVEF,RV/LV ESV volume ratio, RV/LV dimension ratio and main pulmonary artery/aorta dimension ratio in control group were (150.5±24.1) ml,(71.5 ±18.5) ml, (53.5 ±4.2)%, 1.08 ±0.04, 1.01 ±0.04 and 0. 99 ±0. 02, respectively. While those in PE group were ( 190. 3 ± 16. 2) ml, ( 128. 1 ± 13.2) ml,(32.7 ± 3.6 ) %, 2.00 ± 0.26, 1.30 ± 0. 09 and 1.34 ± 0. 11, respectively. Those after therapy of thrombolysis were ( 159. 2 ± 21.5 ) ml, ( 80. 7 ± 9.4) ml, (49. 2 ± 5.9) %, 1.22 ± 0.25, 1.02 ± 0.02 and 1.02±0.11,respectively. ESV and EDV of RV were larger (q= 6.28, P<0.01; q=7.59, P<0.01),EF value was lower (q = 4. 82, P < 0.01 ) in PE group than those in control group. RV/LV ESV volume ratio, the RV/LV dimension ratio and main pulmonary artery/aorta dimension ratio were larger ( q = 6. 04,P <0. 01; q =4. 43, P <0. 01; q =4. 36, P <0. 01 ) and EDV of LV was lower in PE group than those in control group. However, ESV and EDV of RV and RV/LV ESV volume ratio were lower (q = 5.03, P <0.01;q=6. 11,P<0.01;q=4.74,P<0.01), EF value was larger (q=6.29, P<0.01) and EDV of LV was larger(q =4.01 ,P <0.01 ) after therapy of thrombolysis than before. Conclusion Retrospective triple rule-out ECG-gated MSCT can show pulmonary embolism, measure the function of RV and LV and evaluate curative effect of thrombolysis.
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Objective To evaluate the value of contrast-enhanced whole-heart coronary magnetic resonance angiography ( CE CMRA ) at 3.0 T in the delineation of cardiac venous anatomy. Methods Contrast-enhanced whole-heart CMRA at 3.0T was performed in 43 consecutive subjects using ECG-triggered, navigator-gated, inversion-recovery prepared, segmented gradient-echo sequence with a 32-channel cardiac coil. The visibility of the coronary veins was graded visually using a 4-point scale.Continuous variable was expressed as (-x)±s. The paired student t test was used to evaluate the differences of the coronary sinus (CS) ostium diameter in anteroposterior and superoinferior directions. Results CMRA examination was successfully completed in 40 subjects with acquisition time of ( 6. 9 ± 1.8 ) min. The cardiac veins were finally evaluated in 38 of 40 (95.0%) subjects. The mean distance of the posterior vein of the left ventricle (PVLV) and the left marginal vein (LMV) to the CS ostium were (3.34 ± 0. 90) and (6. 12 ± 1.02) cm, respectively. The mean visibility scores of CS, posterior interventricular vein (PIV),PVLV, LMV, and anterior interventricular vein (AIV) were 4.0 ± 0.0, 3.4 ± 0. 5, 3.4 ± 0. 5, 3.0 ± 0. 8,and 3. 3 ± 0. 5, respectively. The diameter of the CS ostium in the superoinferior direction ( 1.13 ±0. 26) cm was larger than that in the anteroposterior direction (0. 82 ± 0. 19) cm (t = -4. 31 ,P <0. 05).Conclusion Contrast-enhanced whole-heart CMRA at 3.0 T can clearly depict the cardiac venous anatomy.
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Objective To evaluate the 80 mm volume shuttle cerebral CT perfusion(CTP) and 4D-CT angiography (CTA) in patients with stenosis or occlusion in Willis circle.Methods Conventional cerebral plain CT, 80 mm CTP and dynamic 4D-CTA were performed in 55 patients with unilateral MCA/ ICA stenosis or occlusion.The parameter maps of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT) and time to peak (TTP) were analyzed.Meanwhile dynamic 4D-CTA images were also obtained.The significance of the differences of CBF, CBV, MTT and TTP between the affected side and the contralateral side was assessed using K Independent Samples analysis.Results In 40 patients with unilateral stenosis or occlusion of MCA/ICA, CTP was found abnormal in 36 patients.MTT and TTP of affected side [(7.18 ±1.34), (19.65 ±1.81) s] were significantly prolonged compared to contralateral side [(5.22±1.14) s, (17.62±1.65) s, X~2 =30.833,25.817, P<0.017].Centrum ovale or parietal lobe ischemic lesions were observed in 16 patients on CTP.In 15 patients with bilateral stenosis or occlusion of MCA/ICA, CTP was observed abnormal in 10 patients.CBF, CBV, MTT and TTP of affected side [(42.85 ±6.09) ml·100 g~(-1)·min~(-1), (2.63 ±0.42) ml·100 g~(-1), (11.27 ±1.43) s, (21.07 ±1.44) s)] were significantly different from those of contralateral side [(71.20 ±6.30) ml·100 g~(-1)·min~(-1), (2.29 ±0.15) ml·100 g~(-1), (3.38 ±0.61) s, (17.64 ±1.70) s (X~2 =17.314, 5.913,17.334,13.834,P<0.017)].On 4D-CTA covering 80 mm (0.625 mm×l28), unilateral stenosis of MCA were observed in 22 patients (13 right MCA and 9 left MCA), unilateral occlusion were observed in 5 patients (1 right MCA and 4 left MCA) and bilateral MCA stenosis/occlusion were observed in 9 patients.4D-CTA covering Willis cycle can display stenosis/occlsion of MCA as same as conventional CTA and DSA.Conclusion 80 mm volume shuttle CTP and 4D-CTA provide valuable information about the hemodynamic changes and the abnormalities of intracranial artery in patients with MCA/ICA stenosis or occlusion.
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Objective To evaluate 64-slice CT angiography in diagnosing spinal vascular malformations. Methods Fifteen patients,who were suggestive of spinal vascular malformations bv clinical manifestation and MRI,underwent CT angiography with a 64-slice spiral CT(GE lightspeed VCT).DSA were performed later within 1 week in all the patients and four of them were treated with operation as well.We evaluated CTA images in displaying the lesions according to the following aspects:the type of malformation,lesion range,feeding artery,draining vein and possible fistula.and compared those details with DSA and operation findings.Results All 15 patients acquired their final diagnosis by DSA and operation,which were intramedullary axteriovenous malformation in 6 cases,perimedullary arteriovenous fistula in 2,spinal dural arteriovenous fistula in 3 and Cobb syndrome in 4 cases. CTA was consistent with DSA in the classification of lesions and in the determination of the involved regions and it reveaIed the main feeding arteries and draining veins in all patients.CTA showed four arteriovenous fistulae confinned bv DSA.but it failed in a complex arteriovcnous fistula.In Cobb syndrome patients,not only the intramedullary but also paravertebral and subcutenous vascular malformation could be clearly seen on CTA images.Conclusion 64-slice CT angiography can be a preliminary method in spinal vascular malformation because it can determine the classification and reveal almost all the main lesions quickly,atraumatically.
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lusions Cardiac MSCT can accurately assess the RV size and function in comparison to MRI. Patients with severe COPD have RV dysfunction.
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3 T CE-CMRA allows for accurate detection of coronary artery stenosis of the main coronary artery branches with high sensitivity and specificity,but is still limited in small coronary branches.
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Objective To probe the application of CT cerebral perfusion imaging on transient ischemic attacks(TIA) Methods Conventional CT and CT cerebral perfusion imaging were performed on 5 normal adults and 20 patients with clinically diagnosed TIA After regular CT examination, dynamic scans of 40 seconds were performed on selected slice (usually on the basal ganglia slice), while 40 ml non ionic contrast material were bolus injected through antecubital vein with These dynamic images were processed with the "Perfusion CT" software package on a PC based workstation Cerebral blood flow (CBF) and time to peak (TP) enhancement were measured within specific regions of the brain on CT perfusion images Quantitative analysis was performed for these images Results A gradient of perfusion between gray matter and white matter was showed on CT perfusion images in normal adults and TIA patients CBF and TP for normal cortical and white matter were 378 2 ml?min -1 ?L -1 , 7 8 s and 112 5 ml?min -1 ?L -1 , 9 9 s, respectively In 20 cases with TIA, persisting abnormal perfusion changes corresponding to clinical symptoms were found in 15 cases with prolonged TP Other 5 cases showed normal results TP of affected side (11 8?4 4) s compared with that of the contralateral side (9 1?3 1) s was significantly prolonged ( t =5 277, P