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Purpose Placenta accreta is a rare but severe pregnancy complications, and imaging diagnosis is always difficult. This paper aims to analyze the MRI manifestations of placenta accreta, and explore its misdiagnosis reasons. Materials and Methods A retrospective study was carried out on the findings and classification of MRI plain scan and diffusion weighted imaging (DWI) scan of 18 patients with placenta accreta confirmed surgically and pathologically. Results The prenatal MRI scan reported 15 patients of placenta accreta correctly (83.33%), and missed 3 (16.67%) among which 2 were with placenta accreta and the other 1 with placenta increta. The MRI of placenta accreta presented rather thin muscular layer, discontinuous junctional zone, and some unclear boundary of placenta and uterine wall; the signal of the placenta was heterogeneous, and we could see enlarged vessels of extremely low signal on T2 HASTE and high signal on TruFISP sequences, and low signal of thick intraplacental band; moreover, hematoma with high intensity on T1WI and low intensity on T2WI could be seen. DWI demonstrated uneven intensity and dark thicker intraplacenta bands in 2 cases. Conclusion As an important clinical auxiliary tool in diagnosing placenta increta, MRI has high accuracy in the diagnosis of placenta increta and placenta percreta; however, it has rather low accuracy in placenta accreta.
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Objective To document the MRI features of renal angiomyolipoma (RAML) containing minimal fat and to explore whether the MR features vary depending on the tumor size. Methods The MR findings of 15 cases of pathologically-proved RAML containing minimal fat were reviewed retrospectively from January 2008 to March 2010. All patients underwent MR in a 1.5 T or 3.0 T scanners. The MR features of the lesions were analyzed, with emphasis on the signal intensity and homogeneity on T2WI, in regards to pseudocapsule, lipid component, hemorrhage, cystic degeneration or necrosis, blood vessels, interface with renal parenchyma and enhancement pattern. All lesions were categorized into 2 groups; those with diameter ＞4 cm and those with diameter ≤4 cm. The difference of imaging characteristics between these two groups was analyzed using Fisher exact test. Results All 15 lesions demonstrated hypointensity on T2WI compared to the renal parenchyma. Homogeneous signal intensity on T2WI was seen in 6 lesions (6/15); peritumoral pseudocapsule in 3 lesions (3/15); cystic degeneration or necrosis, hemorrhage in 5 lesions (5/15); flow void of blood vessels in 2 lesions (2/15); lipid component in 4 lesions (4/15); angular interface with renal parenchyma in 10 lesions (10/15); homogeneous enhancement in 8 lesions (8/15). Fifteen lesions were divided into two groups; 9 categorized into group 1 (the maximum diameter ≤ 4 cm) and 6 into group 2 ( the maximum diameter ＞ 4 cm). Cystic degeneration or necrosis was seen in 0 of 9 in group one and 5 of 6 in group two respectively, hemorrhage(0 of 9 and 5 of 6 respectively) and pseudocapsule(0 of 9 and 3 of 6 respectively. The difference between these findings in the two groups demonstrated statistical significance (P ＜ 0. 05). Conclusion The MR features of RAML containing miminal fat were hypointensity on T2 WI,angular interface with renal parenchyma and homogeneous contrast enhancement, however, these findings can vary depending on the tumor size.
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Objective To evaluate the effect of endoprostheses for short and long term management of common bile duct stones in elderly patients(70 89 years). Methods Fifty two patients over 70 years with common bile duct stones undergone endoscopic biliary stenting(Group S, 28 cases) or common bile duct exploration (Group D, 24 cases) were followed up for 14 85 months. The two groups were similar to each other in clinical manifestations. Results One patient (4 2%) died because of breath and circulation exhausting on the 3rd day postoperation in Group D. Early complications were 14 4% and 33 3% respectively ( P
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ObjectiveTo evaluate the characteristics of MRI of common hepatic lesions by using measurement of T1,T2 and ADC on the MRI and DWI. MethodsMRI and DWI were obtained in 100 patients with common hepatic lesions, and T1,T2,ADCs and the ratios of the ADC of lesion/liver were estimated. (Results)Average T1,T2 and ADCs of hepatic lesions were as follows: hepatocellular carcinoma, (843.92167.75) ms , (73.9014.21) ms and(0.990.26)10~(-3)mm~2/s respectively; hepatic (metastasis), (946.89186.13) ms, (76.3919.76) ms and(1.170.32)10~(-3)mm~2/s (respectively); hepatic cavernous hemangioma, (1102.33213.12)ms, (142.3228.51) ms and (1.810.42)10~(-3)mm~2/s respectively; hepatic cyst, (1516.32617.84)ms ,(247.33112.52)ms and (3.110.38)10~(-3)mm~2/s respectively. The ratio of the ADC of lesion/liver:(hepatocellular) carcinoma was 0.890.17, and significantly lower than the ratio of hepatic metastases((1.27)0.21, P
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Objective To evaluate the possibility and scan the protocol of diffusion tensor imaging(DTI) in rabbit VX2 liver tumor models.Methods MRI and DTI images were obtained from 16 rabbit VX2 liver tumor models and 4 rabbit control liver models.Average diffusion coefficient(ADC),fractional anisotropy(FA) of tumors and control livers were estimated and compared with the changing rules(b value=100,600,1000 mm2/s).Results ADC of tumors had a descending trend and FA of tumors had an increasing trend compared with control livers.The fluctuations of ADC and FA of tumors had a descending trend(P