Objective： To assess if diffusion-weighted magnetic resonance （MR） imaging without apparent diffusion coefficient （ADC） values provides added diagnostic value in combination with conventional MR imaging in the de...Objective： To assess if diffusion-weighted magnetic resonance （MR） imaging without apparent diffusion coefficient （ADC） values provides added diagnostic value in combination with conventional MR imaging in the detection and characterization of small nodules in cirrhotic liver. Methods： Two observers retrospectively and independently analyzed 86 nodules （_〈3 em） certified pathologically in 33 patients with liver cirrhosis, including 48 hepatocellular carcinoma （HCC） nodules, 13 high-grade dysplastic nodules （HDN）, 10 low-grade dysplastic nodules （LDNs） and 15 other benign nodules. All these focal nodules were evaluated with conventional MR images （Tl-weighted, T2-weighted and dynamic gadolinium-enhanced images） and breath-hold diffusion-weighted images （DWI） （b=500 s/mm2）. The nodules were classified by using a scale of 1-3 （1, not seen; 3, well seen） on DWI for qualitative assessment. These small nodules were characterized by two radiologists. ADC values weren＇t measured. The diagnostic performance of the combined DWI-conventional images and the conventional images alone was evaluated using receiver operating characteristic （ROC） curves. The area under the curves （Az）, sensitivity and specificity values for characterizing different small nodules were also calculated. Results： Among 48 HCC nodules, 33 （68.8%） were graded as 3 （well seen）, 6 （12.5%） were graded as 2 （partially obscured）, and 9 weren＇t seen on DWI. Among 13 HDNs, there were 3 （23.1%） and 4 （30.8%） graded as 3 and 2 respectively. Five （50%） of 10 benign nodules were partially obscured and slightly hyperintense. For 86 nodules, the average diagnostic accuracy of combined DWI-conventional images was 82.56%, which was increased significantly compared with conventional MR images with 76.17%. For HCC and HDN, the diagnostic accuracy of combined DWI-conventional images increased from 78.69% to 86.07 %. Conclusions： Diffusion-weighted MR imaging does provide added diag展开更多
目的用氢质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)分析鼻咽癌放疗后颞叶放射性脑病代谢产物改变,探讨1H-MRS在放射性脑损伤中的应用价值。方法鼻咽癌放疗后放射性脑病26例共39个颞叶病灶和健康正常人21例共21个...目的用氢质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)分析鼻咽癌放疗后颞叶放射性脑病代谢产物改变,探讨1H-MRS在放射性脑损伤中的应用价值。方法鼻咽癌放疗后放射性脑病26例共39个颞叶病灶和健康正常人21例共21个颞叶均作1H-MRS,在颞叶脑白质区域测量N-乙酰天门冬氨酸(N-acetylaspartate,NAA)、肌酸(Creatine Cr)、胆碱(Choline,Cho)值。结果放射性脑病脑白质内NAA、PCr、Cho有较明显降低,其差异具有统计学显著性意义(p<0.05),NAA/Cho降低、Cho/PCr升高,两组间比较具有统计学上显著差异(p<0.05),NAA/PCr在放疗后略增高,两组间统计学上无显著性差异(p>0.05)。结论鼻咽癌放疗后迟发性放射性脑病1H-MRS出现异常改变,其脑内三种主要代谢产物均有降低,对放射性脑损伤能起到辅助诊断作用。对放射性脑损伤准确诊断提供了一种新的影像学诊断手段。展开更多
A 7-year-old boy presented with cerebellar ataxia with reduced tonicity, deficits of the fine and gross motor coordination skills and vestibular stimulus processing, as well as significantly delayed language developme...A 7-year-old boy presented with cerebellar ataxia with reduced tonicity, deficits of the fine and gross motor coordination skills and vestibular stimulus processing, as well as significantly delayed language development. MR imaging showed the so-called “molar tooth sign”, which was highly pathognomonic for the Joubert-Syndrome—an inherited cerebellar ataxia with a variety of clinical symptoms—and related entities. It is caused by a complex malformation of the cerebellar vermis and the midbrain. The cerebellar vermis is hypoplastic or completely absent;at the same time, the superior cerebellar peduncles are thickened. There is a lack of normal decussation of the fiber tracts in mesencephalon, which follow an abnormal horizontal course, as well as a lack of the decussation of the corticospinal fiber tracts in the caudal medulla oblongata and deformity of the 4th ventricle. Clinically, the triad of cerebellar ataxia, developmental retardation, and abnormal eye movements is indicating a related syndrome of this spectrum. The appearance of the involved children is characterized by dysmorphic facial features with epicanthus, broad nose bridge, low set ears and typically triangularly shaped and opened mouth. The diagnosis is usually made by imaging and clinical findings. Recently, advantages were made in genetic research on the Joubert syndrome and interesting findings published about diffusion tensor imaging and tractography. However, standard MR imaging, applying an adequate imaging protocol including sequences with excellent T1 contrast and 3D imaging with isotropic spatial resolution allowing reconstructions in all orientations, remains an essential tool for making this diagnosis.展开更多
目的探讨磁共振扩散加权成像对前列腺癌的诊断价值并寻找诊断前列腺癌的适宜阈值。方法 74例前列腺癌疑诊患者行3.0 T MR常规平扫及DWI成像。测量ADC map图中每侧外周带的ADC低值。外周带穿刺发现腺癌为阳性组,无肿瘤证据为阴性组。比...目的探讨磁共振扩散加权成像对前列腺癌的诊断价值并寻找诊断前列腺癌的适宜阈值。方法 74例前列腺癌疑诊患者行3.0 T MR常规平扫及DWI成像。测量ADC map图中每侧外周带的ADC低值。外周带穿刺发现腺癌为阳性组,无肿瘤证据为阴性组。比较阴性组与阳性组,分化较好腺癌组(Gleason评分2～6分)与分化较差腺癌组(Gleason评分7～10分)的ADC低值差异。以ADC低值预测外周带穿刺阳性率,绘制ROC曲线。结果74例患者中146个前列腺侧叶(阴性组50,阳性组96)获得组织学证实,其中分化较好腺癌(Gleason评分2～6分)17个,分化较差腺癌(Gleason评分7～10分)79个。阳性组与阴性组间ADC低值差异有统计学意义(0.92×10-3±0.22×10-3 mm2/s vs 1.48×10-3±0.28×10-3 mm2/s,t=12.27,P=0.00)。分化较好腺癌组与分化较差腺癌组差异有统计学意义(1.04×10-3±0.20×10-3 mm2/s vs 0.89×10-3±0.21×10-3 mm2/s,t=2.60,P=0.01)。分化较好腺癌组与阴性组ADC低值差异亦有统计学意义(t=5.91,P=0.00)。以ADC低值预测外周带穿刺阳性率,ROC曲线下面积为0.95(P=0.00),最佳临界值为1.15×10-3mm2/s,此时判断穿刺阳性的敏感度为85.4%,特异度为92.0%。结论 MR DWI出现对于前列腺癌的诊断具有较高价值,ADC低值小于1.15×10-3mm2/s可能是较适宜的诊断界值。展开更多
基金supported by the Capital Medical Development Foundation(Grant No.2011-2015-02)the National Basic Research Program of China (973 Program)(Grant No.2011CB707705)the Capital Characteristic Clinical Application Research(Grant No.Z121107001012115)
文摘Objective： To assess if diffusion-weighted magnetic resonance （MR） imaging without apparent diffusion coefficient （ADC） values provides added diagnostic value in combination with conventional MR imaging in the detection and characterization of small nodules in cirrhotic liver. Methods： Two observers retrospectively and independently analyzed 86 nodules （_〈3 em） certified pathologically in 33 patients with liver cirrhosis, including 48 hepatocellular carcinoma （HCC） nodules, 13 high-grade dysplastic nodules （HDN）, 10 low-grade dysplastic nodules （LDNs） and 15 other benign nodules. All these focal nodules were evaluated with conventional MR images （Tl-weighted, T2-weighted and dynamic gadolinium-enhanced images） and breath-hold diffusion-weighted images （DWI） （b=500 s/mm2）. The nodules were classified by using a scale of 1-3 （1, not seen; 3, well seen） on DWI for qualitative assessment. These small nodules were characterized by two radiologists. ADC values weren＇t measured. The diagnostic performance of the combined DWI-conventional images and the conventional images alone was evaluated using receiver operating characteristic （ROC） curves. The area under the curves （Az）, sensitivity and specificity values for characterizing different small nodules were also calculated. Results： Among 48 HCC nodules, 33 （68.8%） were graded as 3 （well seen）, 6 （12.5%） were graded as 2 （partially obscured）, and 9 weren＇t seen on DWI. Among 13 HDNs, there were 3 （23.1%） and 4 （30.8%） graded as 3 and 2 respectively. Five （50%） of 10 benign nodules were partially obscured and slightly hyperintense. For 86 nodules, the average diagnostic accuracy of combined DWI-conventional images was 82.56%, which was increased significantly compared with conventional MR images with 76.17%. For HCC and HDN, the diagnostic accuracy of combined DWI-conventional images increased from 78.69% to 86.07 %. Conclusions： Diffusion-weighted MR imaging does provide added diag
文摘目的用氢质子磁共振波谱(proton magnetic resonance spectroscopy,1H-MRS)分析鼻咽癌放疗后颞叶放射性脑病代谢产物改变,探讨1H-MRS在放射性脑损伤中的应用价值。方法鼻咽癌放疗后放射性脑病26例共39个颞叶病灶和健康正常人21例共21个颞叶均作1H-MRS,在颞叶脑白质区域测量N-乙酰天门冬氨酸(N-acetylaspartate,NAA)、肌酸(Creatine Cr)、胆碱(Choline,Cho)值。结果放射性脑病脑白质内NAA、PCr、Cho有较明显降低,其差异具有统计学显著性意义(p<0.05),NAA/Cho降低、Cho/PCr升高,两组间比较具有统计学上显著差异(p<0.05),NAA/PCr在放疗后略增高,两组间统计学上无显著性差异(p>0.05)。结论鼻咽癌放疗后迟发性放射性脑病1H-MRS出现异常改变,其脑内三种主要代谢产物均有降低,对放射性脑损伤能起到辅助诊断作用。对放射性脑损伤准确诊断提供了一种新的影像学诊断手段。
文摘A 7-year-old boy presented with cerebellar ataxia with reduced tonicity, deficits of the fine and gross motor coordination skills and vestibular stimulus processing, as well as significantly delayed language development. MR imaging showed the so-called “molar tooth sign”, which was highly pathognomonic for the Joubert-Syndrome—an inherited cerebellar ataxia with a variety of clinical symptoms—and related entities. It is caused by a complex malformation of the cerebellar vermis and the midbrain. The cerebellar vermis is hypoplastic or completely absent;at the same time, the superior cerebellar peduncles are thickened. There is a lack of normal decussation of the fiber tracts in mesencephalon, which follow an abnormal horizontal course, as well as a lack of the decussation of the corticospinal fiber tracts in the caudal medulla oblongata and deformity of the 4th ventricle. Clinically, the triad of cerebellar ataxia, developmental retardation, and abnormal eye movements is indicating a related syndrome of this spectrum. The appearance of the involved children is characterized by dysmorphic facial features with epicanthus, broad nose bridge, low set ears and typically triangularly shaped and opened mouth. The diagnosis is usually made by imaging and clinical findings. Recently, advantages were made in genetic research on the Joubert syndrome and interesting findings published about diffusion tensor imaging and tractography. However, standard MR imaging, applying an adequate imaging protocol including sequences with excellent T1 contrast and 3D imaging with isotropic spatial resolution allowing reconstructions in all orientations, remains an essential tool for making this diagnosis.
文摘目的探讨磁共振扩散加权成像对前列腺癌的诊断价值并寻找诊断前列腺癌的适宜阈值。方法 74例前列腺癌疑诊患者行3.0 T MR常规平扫及DWI成像。测量ADC map图中每侧外周带的ADC低值。外周带穿刺发现腺癌为阳性组,无肿瘤证据为阴性组。比较阴性组与阳性组,分化较好腺癌组(Gleason评分2～6分)与分化较差腺癌组(Gleason评分7～10分)的ADC低值差异。以ADC低值预测外周带穿刺阳性率,绘制ROC曲线。结果74例患者中146个前列腺侧叶(阴性组50,阳性组96)获得组织学证实,其中分化较好腺癌(Gleason评分2～6分)17个,分化较差腺癌(Gleason评分7～10分)79个。阳性组与阴性组间ADC低值差异有统计学意义(0.92×10-3±0.22×10-3 mm2/s vs 1.48×10-3±0.28×10-3 mm2/s,t=12.27,P=0.00)。分化较好腺癌组与分化较差腺癌组差异有统计学意义(1.04×10-3±0.20×10-3 mm2/s vs 0.89×10-3±0.21×10-3 mm2/s,t=2.60,P=0.01)。分化较好腺癌组与阴性组ADC低值差异亦有统计学意义(t=5.91,P=0.00)。以ADC低值预测外周带穿刺阳性率,ROC曲线下面积为0.95(P=0.00),最佳临界值为1.15×10-3mm2/s,此时判断穿刺阳性的敏感度为85.4%,特异度为92.0%。结论 MR DWI出现对于前列腺癌的诊断具有较高价值,ADC低值小于1.15×10-3mm2/s可能是较适宜的诊断界值。
