磁共振成像短时间反转恢复序列在鼻咽癌中的应用

目的　比较磁共振成像短时间反转恢复序列 (short tauinversionrecovery ,STIR)与快速自旋回波T2加权 (fastspinechoT2weightedimaging ,FSET2WI)在鼻咽癌成像中的应用。方法　 5 0例经手术和病理证实的鼻咽癌病人进行磁共振STIR序列和FSET2WI扫描 ,对两者进行对比度 噪音比值 (C Ns)比较和肿瘤影像征像 (包括肿块边界和肿块内部细节 )清晰程度的比较。结果　STIR序列的C Ns为 2 0 4 1± 3 87,FSET2WI的C Ns为 8 2 4± 1 74。STIR序列比FSET2WI有更高的C Ns ,t=2 0 2 9,P <0 0 1。STIR序列成像对鼻咽癌的边界和内部结构的显示比FSET2WI成像更清楚 ,两者影像征像比较 :鼻咽癌肿块边界 χ2 =2 3 19,P <0 0 1、肿块内部细节 χ2 =16 2 3,P <0 0 1。结论STIR序列在鼻咽癌成像效果比FSET2WI更敏感、更能有效显示鼻咽癌。     

对比增强磁化传递MRI在肺癌脑内小转移灶成像中的价值

目的　探讨对比增强磁化传递 (magnetisationtransfer,MT)MRI在肺癌脑内小转移灶的应用。方法　对 6 0例病人 (含 172个转移灶 )进行对比增强磁化传递前后的对照研究。对比增强磁化传递前采用SE序列T1WI。然后 ,注射钆喷替酸葡甲胺 (Gd DTPA) (0 1mmol/kg)增强后 ,进行SE序列T1WI和SE序列T1WIMT技术成像。通过比较对比度 /噪声比值 (C/Ns值 ) ,对采用MT技术与否的影像结果进行评估 ;再对采用MT技术与否所显示的转移灶数量进行对照。结果　所有采用T1WI对比增强MT技术的图像C/Ns值比常规T1WI对比增强图像的C/Ns值高。采用MT技术图像的C/Ns值为 2 6 98± 7 0 6 ( x±s) ,常规T1WI对比增强图像的C/Ns值为 15 5 1± 8 5 4 ,t =8 0 2 ,P <0 0 1。T1WI对比增强MT技术比常规T1WI对比增强能显示更多的转移灶数目 (6 0个 ) ,χ2 =7 79,P <0 0 1。结论　在显示肺癌脑内小转移灶方面 ,T1WIMT对比增强比常规T1WI对比增强更为敏感 ,对评估中枢神经系统转移性疾病具有重要的临床价值。     

GRE-T_2''WI、FSE-T_2WI、STIR序列在脊柱转移瘤MRI的应用比较

目的:比较3种MRI扫描序列在脊柱转移瘤的应用,探讨各种方法的序列设计特点、信号特点及适用性。方法:50例证实为脊柱转移瘤的患者均进行矢状GRET2WI、FSET2WI、STIR序列扫描,并与矢状T1WI图像对照,比较3种序列对椎体、附件骨质破坏,脊髓受压、受侵,椎间盘、椎旁软组织肿块的显示情况。结果:GRET2WI和STIR序列显示脊柱转移瘤椎体、附件骨质破坏较优;FSET2WI显示脊髓受压、受侵的情况较优;软组织肿块的显示基本一致。结论:矢状GRET2WI可作为脊柱转移瘤常规扫描序列的首选,FSET2WI如有脊髓受压、受侵时可作为常规扫描序列;STIR是常规扫描的补充。     

脊椎转移瘤增强减影MR成像

目的评估增强减影在脊椎转移瘤MR I中的应用价值。方法50例脊椎转移瘤病人进行MR I增强扫描,对比剂采用Gd-DTPA(0.1 mmol/kg),然后用T1W I增强后的图像与增强前的图像进行减影。通过对比噪声比(CNR)、信噪比(SNR)以及肿瘤边界清晰程度的比较,对MR I减影与否进行评估。结果MR I对比增强减影图像比传统的T1W I增强图像显示更清晰、更直观。所有脊椎转移瘤图像MR I减影的CNR和SNR比常规T1W I增强图像的CNR和SNR高。MR I减影CNR为155.05±24.73(x±SD),常规T1W I增强图像的CNR为11.11±14.26(t=35.65,Ρ<0.001)。MR I减影SNR为192.82±32.89(x±SD),常规T1W I增强图像的SNR为46.03±28.22(t=23.95,Ρ<0.001))。MR I对比增强减影图像比传统的T1W I增强图像能更好地显示脊椎转移瘤的边界和侵犯情况(2χ=29.34,Ρ<0.005)。结论MR I增强减影为探查和评估脊椎转移瘤提供了一个新的诊断方法。     

低场MR增强扫描及FLAIR序列对脑转移瘤诊断的评价

目的 :探讨低场MR增强扫描与FLAIR序列在脑转移瘤诊断中的价值。方法 :搜集 2 9例脑转移瘤患者 ,使用 0 .2 3TMR扫描仪 ,对比分析常规T1 WI、T2 WI、增强扫描及FLAIR序列在检出转移瘤和明确转移瘤边界方面的敏感性。结果 :增强扫描对转移瘤检出以及明确转移瘤边界的敏感性高于FLAIR、T2 WI及T1 WI ,经统计分析其差异有极显著性意义 (P <0 .0 1)。对于直径 <1.0cm的软脑膜转移瘤及皮质近蛛网膜下腔处转移瘤的检出及明确肿瘤边界的敏感性FLAIR高于常规T2 WI ,差异有显著性意义 (P <0 .0 5 ) ;对于直径≥ 1.0cm的软脑膜转移瘤、皮质近蛛网膜下腔处转移瘤及深部脑转移瘤 ,FLAIR与常规T2 WI检查差异无显著性意义 (P >0 .0 5 )。结论 :脑转移瘤的低场MRI诊断 ,增强扫描是最有价值的检查方式 ,而FLAIR可取代常规T2 WI。     

DWI结合T2WI在包膜期脑脓肿与囊性转移瘤鉴别诊断中的价值

目的 探讨磁共振扩散加权成像(DWI)结合T2WI在包膜期脑脓肿和囊性脑转移瘤鉴别诊断中的价值.方法 回顾性分析经病理或临床随访证实的23例包膜期脑脓肿和24例脑囊性转移瘤患者的MRI常规平扫、增强及DWI检查资料,b值取0、500 s/mm2、1000 s/mm2,根据信噪比(SNR)及图像质量指数(QI)取最佳b值的DWI,分别测量病灶囊变区、囊壁、对侧正常脑组织平均ADC值并计算3项rADC值,两组间采用两独立样本t检验进行统计学分析.结果 包膜期脑脓肿T2WI低信号暗带及靶环征是鉴别囊性转移瘤的MRI特征性表现.取b值1000s/mm2时,脑囊性转移瘤囊变坏死区DWI呈低信号22例,高信号1例,囊变坏死区、囊壁、对侧正常脑组织平均ADC值分别为(0.64±0.14)×10-3mm2/s、(1.56 ±0.17)×10-3mm2/s、(0.79±0.18)×10-3mm2/s,脑囊性转移瘤囊壁rADC值、病灶rADC值、囊液rADC值分别为1.19±0.37、0.48 ±0.25、2.74±0.75.包膜期脑脓肿囊液DWI呈高信号,包膜期脑脓肿囊变区、囊壁、对侧正常脑组织平均ADC值分别为(2.10±0.28)×10-3mm2/s、(1.51±0.09)×10-3mm2/s、(0.81±0.15)×10-3mm2/s,包膜期脑脓肿囊壁rADC值、病灶rADC值、囊液rADC值分别为1.37±0.48、1.49±0.62、0.95±0.50.包膜期脑脓肿与脑囊性转移瘤囊液ADC值、病灶rADC值、囊液rADC值差异均有显著统计学意义(P＜0.01),囊壁ADC值、囊壁rADC值差异均无统计学意义(P＞0.05).结论 包膜期脑脓肿壁上T2WI特征性的低信号暗带及靶环征有别于囊性转移瘤,b值=1000 s/mm2时囊液DWI、囊液ADC值、病灶rADC值、囊液rADC值能有效反映包膜期脑脓肿与囊性脑转移瘤的不同囊液性质,DWI结合T2WI对包膜期脑脓肿与囊性脑转移瘤的鉴别诊断具有重要价值.     

DWI及ADC图对脑瘤及瘤样病变诊断价值的探讨(附57例分析)

目的 :探讨磁共振扩散加权图像 (DWI)与表观扩散系数 (ADC)图对脑瘤及瘤样病变的诊断价值及相关的生物物理学机制。方法 :对 5 7例病理或临床证实为脑瘤或瘤样病变的患者进行常规MR检查及EPI SE扩散成像检查。其中胶质瘤 2 5例 ,转移瘤 14例 ,脑膜瘤 11例 ,原始神经外胚层瘤 1例 ,恶性纤维组织细胞瘤 1例 ,造血系统肿瘤累及脑 1例 ,脑脓肿 2例 ,病毒性脑炎 2例。测定并比较各种类型脑瘤、级别不同胶质瘤、不同组织成分的ADC值。比较DWI、ADC图与增强T1WI,T2 WI鉴别病灶组织成分的能力及差别。结果 :胶质瘤、转移瘤、脑膜瘤的ADC值分别为 ( 1.16± 0 .2 1)、( 0 .97± 0 .2 6 )、( 1.0 9± 0 .2 8)× 10 -9m2 /s,无明显差异 (P =0 .0 6 ;P =0 .4 4 )。脑内炎性病变和粒细胞白血病脑内浸润灶的ADC值比较低。低级别星形细胞瘤 ( 1.2 8± 0 .16 )× 10 -9m2 /s比间变型 ( 1.11± 0 .13)× 10 -9m2 /s和胶质母细胞瘤 ( 0 .82± 0 .13)× 10 -9m2 /s的ADC值高 (P <0 .0 5 )。瘤灶、水肿、坏死等各组织成分ADC值分别为 ( 1.11± 0 .16 )、( 1.6 2± 0 .19)、( 2 .39±0 .18)× 10 -9m2 /s,有显著差异 (P <0 .0 0 1)。DWI可显示未增强星形细胞瘤 ,较增强T1WI及T2 WI敏感。结论 :ADC值对胶质瘤、转移瘤、脑膜瘤无     

海绵窦影像检查方法比较研究

目的对正常CS的CT和MRI序列比较研究,探讨CS实用影像检查方法.方法60例鞍区及CS正常的病人分为三组①20例行SET1WI、FSET2WI、脂肪抑制SET1WI、GRET1WI和SET1WI增强扫描;②20例行3DSPGR和高分辨FSET2WI;③另20例行冠状CT增强扫描.采用双盲法评价并比较(秩和检验)8种检查方法对CS区正常解剖结构的显示能力和伪影程度.结果(1)显示CS内第Ⅲ、Ⅴ1和Ⅵ对颅神经SET1WI增强扫描和CT增强扫描优于其他6种序列(Ρ＜0.05);(2)显示CS边缘GRET1WI和3DSPGR不如其他6种方法(Ρ＜0.05);(3)显示CS间隙GRET1WI、3DSPGR和高分辨FSET2WI不如其他5种方法(Ρ＜0.05);(4)显示ICAGRET1WI、3DSPGR、高分辨FSET2WI和CT增强扫描不如其他4种方法(Ρ＜0.05);(5)显示骨结构CT优于MRI各序列(Ρ＜0.05);(6)磁敏感伪影GRET1WI、3DSPGR和高分辨FSET2WI多于其他序列(Ρ＜0.05);(7)ICA相位方向伪影GRET1WI和3DSPGR多于其他序列(Ρ＜0.05).结论CS区首选检查为冠状位SET1WI和FSET2WI;脂肪抑制SET1WI和SET1WI增强扫描可在必要时使用;疑有骨结构改变时,需使用CT或CT增强扫描;GRET1WI和3DSPGR不适于CS区检查.     

脊柱转移瘤的MRI诊断(附42例分析)

脊柱是恶性肿瘤最常见的转移部位之一 ,国内文献报道脊椎转移瘤约占 5 8.4 % [1,2 ] 。MRI能早期地显示骨转移 ,无假阳性[3] 。笔者搜集了 4 2例脊柱转移瘤病例 ,对其MRI表现进行归纳分析 ,旨在提高其诊断与鉴别诊断水平。材料与方法4 2例脊柱转移瘤其原发瘤均经手术或细胞学穿刺及病理证实 ,其中肺癌 1 5例 ,前列腺癌 1 2例 ,乳腺癌 6例 ,胃癌、结肠癌各 3例 ,卵巢癌、甲状腺癌、肾癌各 1例。年龄 30～ 6 8岁 ,平均 4 9岁。使用GE 0 .5TSigna contour机型 ,常规自旋回波序列 :矢状位SET1WI(TR 4 0 0～ 6 0 0ms,TE 2 2ms) ,FSET2 …     

磁共振稳态采集快速成像序列评价膝关节透明软骨实验研究

目的 探讨磁共振稳态采集快速成像序列(FIESTA)在软骨成像中的应用价值.方法 以新鲜的正常巴马香猪后膝关节为研究对象,进行扫描角度相同的不同序列MR扫描,扫描序列包括T1加权自旋回波序列(SET1WI)、T2加权快速自旋回波序列(FSET2WI),附加脂肪抑制的三维快速扰相梯度回波序列(FS3DSPGR)及稳态采集快速成像序列(FIESTA).在股骨髁间凹中央层面分别测量股骨远端软骨、股骨干骺端骨髓、半月板、韧带、关节腔滑液和背景噪声信号强度(SI),计算软骨信噪比(SNR)和软骨-骨髓、软骨-滑液、软骨-半月板、软骨-韧带对比噪声比(CNR),通过对SNR以及CNR的分析比较,评价各个序列对软骨显示的效果.结果 FIESTA序列在关节软骨显示中,无论SNR,还是CNR均显著优于常 规SET1WI、FSET2WI序列(P＜0.05).FIESTA序列中软骨与滑液、软骨与半月板、软骨与韧带间CNR较高(P＜0.05).结论 FIESTA序列能有效地显示关节透明软骨,在关节软骨形态学的评价中具有潜在的应用价值.     

T2-Weighted Liver MRI Using the MultiVane Technique at 3T: Comparison with Conventional T2-Weighted MRI

Objective

To assess the value of applying MultiVane to liver T2-weighted imaging (T2WI) compared with conventional T2WIs with emphasis on detection of focal liver lesions.

Materials and Methods

Seventy-eight patients (43 men and 35 women) with 86 hepatic lesions and 20 pancreatico-biliary diseases underwent MRI including T2WIs acquired using breath-hold (BH), respiratory-triggered (RT), and MultiVane technique at 3T. Two reviewers evaluated each T2WI with respect to artefacts, organ sharpness, and conspicuity of intrahepatic vessels, hilar duct, and main lesion using five-point scales, and made pairwise comparisons between T2WI sequences for these categories. Diagnostic accuracy (Az) and sensitivity for hepatic lesion detection were evaluated using alternative free-response receiver operating characteristic analysis.

Results

MultiVane T2WI was significantly better than BH-T2WI or RT-T2WI for organ sharpness and conspicuity of intrahepatic vessels and main lesion in both separate reviews and pairwise comparisons (p < 0.001). With regard to motion artefacts, MultiVane T2WI or BH-T2WI was better than RT-T2WI (p < 0.001). Conspicuity of hilar duct was better with BH-T2WI than with MultiVane T2WI (p = 0.030) or RT-T2WI (p < 0.001). For detection of 86 hepatic lesions, sensitivity (mean, 97.7%) of MultiVane T2WI was significantly higher than that of BH-T2WI (mean, 89.5%) (p = 0.008) or RT-T2WI (mean, 84.9%) (p = 0.001).

Conclusion

Applying the MultiVane technique to T2WI of the liver is a promising approach to improving image quality that results in increased detection of focal liver lesions compared with conventional T2WI.     

Assessment of relative brain iron concentrations using T2-weighted and T2*-weighted MRI at 3 Tesla

In this paper a new method is presented for the relative assessment of brain iron concentrations based on the evaluation of T₂ and T₂* -weighted images. A multiecho sequence is employed for rapid measurement of T₂ and T₂*, enabling calculation of the line broadening effect ( T₂′). Several groups have failed to show a correlation between T₂ and brain iron content. However, quantification of T₂′, and the associated relaxation rate R₂′, may provide a more specific relative measure of brain iron concentration. This may find application in the study of brain diseases, which cause associated changes in brain iron levels. A new method of field inhomogeneity correction is presented that allows the separation of global and local field inhomogeneities, leading to more accurate T₂* measurements and hence, T₂′ values. The combination of T₂*, and T₂-weighted MRI methods enables the differentiation of Parlkinson's disease patients from normal age-matched controls based on differences in iron content within the substantia nigra.     

Preoperative 3T MR imaging of rectal cancer: local staging accuracy using a two-dimensional and three-dimensional T2-weighted turbo spin echo sequence

PURPOSE: The purpose of our study was to evaluate the image quality and diagnostic performance of two-dimensional (D) turbo spin echo (TSE) and 3D T2-weighted TSE MR imaging in local staging of rectal cancer at 3T. MATERIALS AND METHODS: 3T phased-array MR imaging was performed in 36 consecutive patients with biopsy-proven rectal cancer. High-resolution 2D TSE images in three planes and 3D TSE images of the rectum were obtained. Two independent observers performed an image quality assessment using eight image quality characteristics. All 2D and 3D datasets were evaluated separately. MR images were prospectively evaluated by two experienced radiologists in consensus with regard to local disease. Total mesorectal excision was used as the standard of reference. The sensitivity, specificity, positive and negative predictive value, and overall accuracy were calculated. Areas under the receiver operating characteristic (ROC) curve (AUC) were determined. RESULTS: Twenty-two patients who underwent a total mesorectal excision were enrolled in this study. Significantly more motion artifacts were present with 3D TSE imaging (P=0.04). The overall sensitivity, specificity, and accuracy of muscularis propria invasion in rectal cancer using 2D T2-weighted images were 100%, 66%, and 95%, respectively. There was a statistical significant greater AUC using 2D T2-weighted images compared to 3D T2-weighted MR images (P=0.04). The ROC curves describing the results of the interpretation of 2D and 3D T2-weighted datasets regarding perirectal tissue invasion showed no statistical significant difference (P=0.41). CONCLUSIONS: In this study, high local staging accuracies with 3T 2D T2-weighted MR imaging were demonstrated. 3D T2-weighted MR imaging cannot replace 2D MR imaging for local staging of rectal cancer. However, 3D MR imaging can be used for visualization of the complex pelvic anatomy for treatment planning purposes.     

Signs of patellar chondromalacia on sagittal T2-weighted magnetic resonance imaging

We incidentally noted distinctive high signal defects or fissures in the patellar articular cartilage on sagittal T2-weighted magnetic resonance (MR) images in 4 patients. At subsequent arthroscopy all 4 patients were found to have patellar chondromalacia. To determine the reliability of these signs, we retrospectively evaluated, in a blinded manner, sagittal T2-weighted MR images of the knee in 75 patients who were undergoing arthroscopic assessment of their patellar articular cartilage. We identified high signal defects or fissures in the patellar cartilage of 5 patients. Patellar chondromalacia was noted at arthroscopy in all 5 patients. Arthroscopy demonstrated patellar chondromalacia in an additional 21 patients with normal MR images. We conclude that high signal defects or fissures on sagittal T2-weighted images are useful signs of patellar chondromalacia. This single imaging sequence will, however, detect only a small number of the cartilage lesions that may be present.     

Clinical utility of partial flip angle T2-weighted spin-echo imaging of the brain

Summary To assess the clinical usefulness of partial flip angle (PFA) spin-echo (SE) brain imaging, a total of eighty patients were examined with both conventional double echo T2-weighted SE (2500/30, 80/90^o/one excitation) and PFA double echo SE (1200/30, 70/45^o/two excitations) on 2.0T system. Two comparative studies were performed: (1) in 65 patients PFA SE technique was compared with conventional SE without flow compensating gradients, and (2) in 15 patients the former was compared with the latter with flow compensating gradients. Imaging time was nearly identical in each sequence. In both studies we found that PFA T2-weighted SE images were almost identical to those obtained with the conventional SE technique in the contrast characteristics and the detection rate of the abnormalities (100%, 85/85 lesions), and more importantly, PFA SE revealed few flow artifacts in the brain stem, temporal lobes and basal ganglia which were frequently seen on conventional SE without flow compensating gradients. Additionally, PFA SE images demonstrated no suppression of CSF flow void in the aqueduct which was commonly seen on conventional SE with flow compensating gradients. In overall image quality, the PFA SE images, particularly the second echo images, were almost comparable with those of conventional SE with flow compensating gradients. A flip angle of 45^o seems to be close to Ernst angle, the angle at which maximum signal occurs, for a given TR of 1200 msec for CSF and most of the abnormalities containing higher water content. In conclusion, PFA SE sequence (i. e. 1200/30, 70/45^o/2) appears to be useful as a primary or an adjunctive technique in certain clinical circumstances, particularly in imaging of hydrocephalic patients for assessing aqueductal patency.     

Chronic lower extremity lymphedema: A comparative study of high-resolution interstitial MR lymphangiography and heavily T2-weighted MRI

Purpose

To assess the role of heavily T2-weighted image and interstitial MR lymphangiography (MRL) for the visualization of lymphatic vessels in patients with disorders of the lymphatic circulation.

Methods

Forty lower extremities in 31 patients (9 bilateral and 22 unilateral) with primary lymphedema were examined by heavily T2-weighted image and indirect MRL. Maximum-intensity projection (MIP) was used to reconstruct the images of the lymphatic system. Two experienced radiologists analyzed the images with regard to the differences in image quality, number of lymphatic vessels, its maximum diameter and two other findings: accumulated lymph fluid in the tissue and honeycombing pattern.

Results

The beaded appearance of the affected vessels in 73 leg segments of 40 lower extremities were present on both modalities 3D MIP. Larger amount of the dilated lymphatic vessels were visualized on heavily T2-weighted image than that on MRL (p = 0.003) and the maximum diameter of it was 4.28 ± 1.53 mm on heavily T2-weighted image, whereas 3.41 ± 1.05 mm on MRL (p < 0.01). The dilated lymphatic vessels on MRL showed better image quality and greater SNR and CNR than that on heavily T2-weighted image (p < 0.01). The regions of accumulated lymph fluid and the honeycombing pattern extent were identified on heavily T2-weighted image scored statistically higher than that on MRL (p < 0.01).

Conclusion

The heavily T2-weighted imaging has greater sensitivity and the MRL image has higher legibility for detecting the pathologically modified lymphatic vessels and accompanying complications non-invasively. Combining these two MR techniques can accurately access the pathological changes in the lower extremity with lymphedema.     

Cortical T2 signal shortening in amyotrophic lateral sclerosis is not due to iron deposits

Signal shortening of the motor cortex in T2-weighted MR images is a frequent finding in patients with amyotrophic lateral sclerosis (ALS). The cause of signal shortening in ALS is unknown, although iron deposits have been suggested. To test this hypothesis, we acquired T2*-weighted gradient-echo (GRE) MR images in addition to T2-weighted turbo spin-echo in 69 patients with ALS. Signal shortening in T2-weighted images was found in 31 patients. In T2*-weighted GRE images, only three patients had signal shortening. One patient with additional bifrontal haemorrhage had frontal but no motor cortex signal shortening. Iron deposits do not cause cortical signal shortening in patients with ALS predominantly. Other factors are presumably more important in the generation of cortical T2 shortening in ALS.     

Rapidly enhancing hepatic hemangiomas at MRI: Distinction from malignancies with T2-weighted images

The purpose of this study is to describe a subset of atypical hepatic hemangiomas that enhance rapidly and diffusely and to determine whether heavily T2-weighted images could distinguish between atypically enhancing liver hemangiomas and hypervascular malignancies. A retrospective search of MR records identified seven patients with liver hemangiomas that demonstrated diffuse early enhancement and 23 patients with biopsy-proven malignant liver lesions that were hypervascular on dynamic gadolinium-enhanced MR images. Quantitative analysis of signal intensity measurements was performed on the T2-weighted images, heavily T2-weighted (TE < 140), and dynamic gadolinium-enhanced images. Blinded reader comparison of the T2-weighted images and gadolinium-enhanced images was performed. Hypervascular hemangiomas enhanced to a greater degree than hypervascular malignant liver lesions on the early phase gadolinium-enhanced images. Perilesional parenchymal enhancement was demonstrated in five cases of rapidly enhancing hemangiomas. Signal intensity and contrast-to-noise ratios on the heavily T2-weighted images of the hemangiomas were significantly greater than that of the hypervascular malignant lesions (P < .05). Hemangiomas were differentiated from the hypervascular malignant liver lesions with high accuracy (97–100%) by three blinded readers based on the T2-weighted images. A subset of hemangiomas have atypical rapid diffuse enhancement on dynamic gadolinium-enhanced images. These atypical hemangiomas can be distinguished from hypervascular malignant liver lesions on T2-weighted MR images.     

T—2四醇和T—2五醇的制备

目的：进一步探讨Ｔ－２毒素与其结构效应的关系，制备Ｔ－２毒素的两个衍生物。Ｔ－２和Ｔ－２五醇。