高脂饮食大鼠高住高练模型的建立

目的:建立高脂饮食致肥胖大鼠的高住高练0～4周动物模型,观察高住高练对肥胖大鼠的时序性影响。方法:出生21天离乳SD雄性大鼠280只,体重(42.7±4.7)g,随机选20只普通饲料喂养,其余260只高脂饲料喂养,自由饮食饮水。饲养10周后,随机选取普通饮食大鼠和高脂饮食大鼠各10只,称重、量身长,计算体重指数;取肾周和附睾脂肪垫称重计算脂体比;取血测血脂;从体重、体脂和血脂角度验证肥胖与否。验证肥胖后从高脂饮食组挑选出160只肥胖大鼠,进行适应性训练,确定常氧下训练强度为26 m/min。根据适应训练的情况保留130只大鼠进行正式实验,分成对照组,低住低练1、2、3、4周组,低氧安静1、2、3、4周组,高住高练1、2、3、4周组,保证各组间大鼠体重无显著性差异。用水平动物跑台进行耐力训练,持续运动1 h/d,6 d/w,1～4 w。低氧氧浓度为13.6%(约相当于3500 m高度)。根据血乳酸确定低氧下训练强度。结果:饲养10周后,普通饮食大鼠体重(425.1±54.2g)和身长(24.0±1.3cm)均显著(P<0.05)高于高脂饮食大鼠(362.7±37.9 g;22.3±0.7 cm),两组大鼠肾周脂肪和附睾脂肪重绝对值之间无显著差异,高脂饮食大鼠体重指数(320.39±13.55)和脂体比(0.99±0.15)%均高于普通饮食组(305.48±11.49,0.61%±0.29%),且具有显著性(P<0.05)和高度显著性(P<0.01)差异。高脂饮食大鼠胆固醇(1.91±0.26 mmol/L)、甘油三酯(0.59±0.25mmol/L)水平显著性(P<0.05)和高度显著性(P<0.01)高于普通饮食组(1.58±0.21 mmol/L、0.40±0.14 mmol/L),高脂饮食组大鼠低密度脂蛋白(0.20±0.04 mmol/L)与普通饮食组大鼠(0.15±0.03mmol/L)比较,高度显著性升高(P<0.01)。常氧26 m/min与低氧21 m/min运动后大鼠血乳酸较为接近。结论:(1)高脂饮食大鼠具有体脂比例、大鼠体重指数和血脂代谢紊乱的多重表现,可视为肥胖造模成功。(2)常氧下25～26 m/min的训练强度和13.6%低氧下20～21 m/min的训练强度相对于高脂饮食大鼠的代谢反应来说是相同的。     

用MR扩散张量成像评价犬急性脊髓损伤后神经前体细胞移植的作用

目的用MR扩散张量成像(diffusiontensorimaging,DTI)观察神经前体细胞移植对犬急性脊髓损伤的影响。方法经端粒酶转染人胚胎脑室下区(subventricularzone,SVZ)细胞建立永生化的神经前体细胞系,并转基因表达绿色荧光蛋白(greenfluorescentprotein,GFP)用于标记和示踪。制作犬T13脊髓左半横断损伤模型。8只犬于损伤后1周行细胞移植,移植点取脊髓半切损伤头侧和尾侧邻近区域的灰白质交界处,不用免疫抑制剂。分别于损伤前、损伤后1周、移植后1周(即损伤后2周)、移植后4周用DTI测量损伤侧和未损伤侧的表观扩散系数(apparentdiffusioncoefficient,ADC)值及部分各向异性(fractionalanisotropy,FA)值,并对结果进行统计学分析。结果损伤前、损伤后1周、移植后1周、移植后4周损伤侧的ADC值分别为(1.00±0.15)、(1.65±0.45)、(1.44±0.48)、(1.43±0.26)×10-3mm2/s,不同时间的差异有统计学意义(F=6.038,P=0.005);损伤侧的FA值分别为0.59±0.11、0.30±0.17、0.36±0.25、0.34±0.11,不同时间的差异有统计学意义(F=5.221,P=0.009)。未损伤侧的ADC值分别为(1.01±0.17)、(1.32±0.06)、(1.10±0.24)、(1.14±0.22)×10-3mm2/s,不同时间的差异无统计学意义(F=1.303,P=0.306);未损伤侧的FA值分别为0.60±0.09、0.38±0.25、0.46±0.15、0.50±0.21,不同时间的差异无统计学意义(F=2.797,P=0.072)。结论DTI对实验性脊髓损伤后脊髓损伤和修复过程的观察能提供有价值的信息。     

100例正常人脑底动脉直径的MR血管成像测量

目的　测量并建立国人正常脑底动脉直径磁共振血管成像 (MRA)正常值。方法　常规MR检查脑实质及脑动脉三维时间飞越法 ( 3DTOF)MRA检查脑底动脉表现无异常者 10 0例 ,其中男5 3例 ,女 47例 ,年龄 4～ 75岁 ,平均 45 8岁 ;≤ 14岁者 12例 ,>14岁者 88例。采用投影仪放大胶片间接测量法测量各脑动脉直径 ,分析其左右侧、年龄和性别上的差异性 ,并统计出各动脉直径的正常参考值。结果　各脑动脉直径测量值为 :眼动脉 (OphA)男为 ( 0 8± 0 2 )mm ,女为 ( 0 9± 0 2 )mm ;颈内动脉 (ICA)C2段男为 ( 3 0± 0 3)mm(≤ 14岁 )和 ( 3 5± 0 6 )mm( >14岁 ) ,女为 ( 2 8± 0 6 )mm(≤14岁 )和 ( 3 1± 0 5 )mm( >14岁 ) ;ICAC4段男为 ( 4 3± 0 6 )mm ,女为 ( 3 9± 0 6 )mm ;大脑前动脉(ACA)A1段男为 ( 2 1± 0 4)mm ,女为 ( 2 1± 0 4)mm ;前交通动脉 (ACoA)男为 ( 1 4± 0 4)mm ,女为( 1 3± 0 4)mm ;大脑中动脉 (MCA)M1段男为 ( 2 7± 0 4)mm ,女为 ( 2 6± 0 4)mm ;基底动脉 (BA)男为 ( 2 9± 0 5 )mm ,女为 ( 2 8± 0 4)mm ;大脑后动脉 (PCA)P1段男左为 ( 2 1± 0 5 )mm、右为 ( 2 0±0 5 )mm ,女左为 ( 2 0± 0 3)mm、右为 ( 1 9± 0 3)mm ;PCAP2段男为 ( 1 8± 0 4)mm     

急性脑出血三种治疗方法疗效比较

目的 :探讨穿刺引流治疗高血压脑出血的疗效及其治疗方案。方法 :将高血压脑出血 189例随机分为钻颅抽吸、锥颅碎吸及药物治疗 3组 ,综合评定各组的疗效 ,并分析比较两种穿刺的治疗时机 ,提出治疗方案。结果 :(1)高血压脑出血 6 3例经锥颅碎吸治疗 ,其总有效率 76 2 % ,与药物治疗 4 9 2 %相比 ,两组差异显著 (P <0 0 5 ) ;与钻颅抽吸治疗 (70 5 % )相比 ,两组差异不显著 ,经Ridit分析发现两组区间重叠极少 ,说明锥颅碎吸在提高病人生活质量方面有一定优势 ;(2 )锥颅碎吸疗法在发病 2 4h内穿刺的有效率为87% ,比钻颅抽吸组 (5 5 % )高 ,两者差异显著 (P <0 0 5 ) ;在 2 4h后穿刺的有效率为 6 5 4 % ,比钻颅抽吸组(87 5 % )低 ,两组差异显著 (P <0 0 5 ) ;(3)头颅CT结果提示 ,穿刺引流组脑内血肿吸收比药物治疗组显著增快。结论 :锥颅碎吸治疗能显著改善病人生活质量 ;发病 2 4h内的病人推荐锥颅碎吸方案 ,2 4h后的病人推荐钻颅抽吸方案     

乳癌相关肽及肠三叶因子在应激胃粘膜损伤的早期修复作用

为了研究乳癌相关肽 (pS2 ,为三叶肽家族一员 )、肠三叶因子 (intestinaltrefoilfactor,ITF ;为三叶肽家族一员 )在水浸束缚应激(WRS)大鼠胃粘膜基因表达变化 ,探讨其在应激胃粘膜损伤的早期修复作用。采用单次水浸束缚应激制作模型 ,动态监测胃粘膜血流量(GMBF) ,大体及光镜下观察粘膜损伤程度(UI)及组织学变化 ,逆转录 多聚酶链反应 (RT PCR)检测pS2 、ITF基因表达变化 ,免疫组化染色进一步证实其表达。结果显示 :应激造成胃粘膜广泛损伤 ,但损伤指数在 2、4、8h逐渐减小 ,至 8h降为 6 4 9% ,GMBF逐渐恢复 ,至8h上升为正常的 89 8% ,ITF基因表达逐渐增强(0 0 2 2±0 0 0 1vs0 177±0 0 10 ,P <0 0 1) ,免疫组化染色计分为 (0 134± 0 0 0 1vs0 2 5 3±0 0 1,P <0 0 1) ;pS2 基因表达逐渐增强 (0 5 1± 0 14vs 0 77± 0 11,P <0 0 1) ,免疫组化染色计分为 (0 95± 0 11vs 1 4 1± 0 0 4 ,P <0 0 1)。提示pS2 、ITF可能均参与了胃粘膜早期重建     

牛腔前卵泡的简易分离方法

采用两种机械方法分离成年牛卵巢腔前卵泡。方法 1:将卵巢用自制刀具切碎 ,吸管吹打悬浮 ,直接离心后检卵。方法 2 :将吸管吹打的悬浮液进行两次网筛过滤 ,离心后检卵。结果表明 ,两种分离方法对腔前卵泡采集数量无显著影响(P >0 .0 5 ) ,平均每个卵巢采集量分别为 179.44± 5 3 .87和 2 0 0 .2 5± 10 5 .5 ,但在处理时间上 ,方法 1与方法 2分别为 2 9.67± 5 .5 3min和 3 8.2 5± 9.86min ,两者差异显著(P <0 .0 5 )。方法 1效果为好 ,在所分离的腔前卵泡中 ,以初级卵泡最多( 5 5 .0 8%) ,其次为次级卵泡 ( 2 9.40 %) ,原始卵泡数量最少 ( 15 .82 %)。     

1ml注射器辅助法在桡动脉穿刺置管中的应用

目的探讨一种新型穿刺法即1 ml注射器辅助法在桡动脉置管的应用,观察其置管成功率与穿刺所需时间。方法选取300例重大手术需动脉穿刺置管的患者,随机分为两组,Ⅰ组采用直接穿刺置管法,Ⅱ组采用1 ml注射器辅助穿刺法。结果Ⅰ组穿刺成功123例,Ⅱ组穿刺成功141例,两组相比,有显著统计学意义(P<0.01);前者用时(56±10.4)s,后者(34±9.3)s(P<0.01)。结论1 ml注射器辅助穿刺是简单、快速、安全且损伤较小的动脉穿刺方法。     

锁骨下静脉穿刺与头静脉切开途径安置心脏起搏器的随机对照研究

目的　比较锁骨下静脉穿刺与头静脉切开途径安置心脏起搏器的价值。方法　将 10 0例需安置心脏起搏器的患者随机分为锁骨下静脉穿刺组和头静脉切开组 (均包括单腔亚组和双腔亚组 ) ,每组各 5 0例患者。观察两种手术径路安置起搏器的手术时间、X线曝光时间、手术并发症及患者对手术切口及囊袋的满意度。结果　无论是手术时间 ,还是X线曝光时间 ,锁骨下静脉组中单腔亚组及双腔亚组均比头静脉组中的对应亚组为短 [(6 4.1± 14 .2min与 (73.8± 11.6 )min ,(86 .4± 13.2 )min与 (10 6 .5± 19.4 )min和(3.4 5± 0 .83)min与 (4 .5 1± 2 .2 7)min ,(5 .5 9± 0 .78)min与 (8.2 7± 4 .91)min ,P均 <0 .0 5 ]。锁骨下静脉穿刺组心室电极导线放置成功率为 10 0 % ,而头静脉切开组则为 5 6 % ,两者亦有显著性差异 (P <0 .0 5 )。而两组并发症发生率无差异 (P >0 .0 5 )。患者对切口及囊袋的满意程度 ,锁骨下静脉组明显高于头静脉组(P <0 .0 1)。结论　只要锁骨下静脉穿刺技术熟练 ,安置心脏起搏器可首选锁骨下静脉穿刺。     

CT引导脑内血肿穿刺抽吸术(附高血压壳核出血30例分析)

本文介绍了CT引导下的脑内血肿穿刺抽吸术方法及注意事项。分析了30例高血压壳核出血(HPH)在血肿抽吸术前、后73次CT扫描图像。本组抽吸术前血肿容积为5～166.8ml(平均41.5±33.2ml);抽吸术后高密度区缩小和CT值下降分别为1.75±1.2mm/d和1.6±1.0Hu/d,比自行吸收快一倍左右。血肿清除率为52％～88％(平均76.1％±18.5％)。死亡率(16.7％)比保守疗法(30％)低。抽吸时间在出血停止、病情基本稳定时就可进行,以发病后24h内为宜。血肿量30～50ml采用本法效果较好,由于血液凝固造成针刺抽吸困难,应加尿激酶(uk)溶解,定时经引流管抽吸,直至彻底清除血肿。本法操作简单安全,局麻下可手术,脑实质损伤小,高龄或危重病人均可耐受,且早期效果显著,值得推广应用。     

兔视神经间接损伤的视神经组织压观察

目的　通过观察兔视神经间接损伤后视神经组织压的变化 ,探讨视神经间接损伤后继发性损伤机制。　方法　一侧视神经致伤后 2 4h ,采用微穿刺法分别记录损伤侧及对侧球后 2mm处视神经组织压的变化 ,并取测压开始后 40～ 6 0min的平均压力值进行分析比较。　结果　视神经间接损伤后 2 4h ,损伤侧视神经组织压 (0 .315± 0 .334 )kPa(1kPa =7.5mmHg)显著高于对侧 (- 0 .0 85± 0 .2 13)kPa (P <0 .0 1)。　结论　视神经间接损伤后视神经组织压显著增高 ,提示有必要实施视神经减压术。     

320排动态容积CT在评价冠状动脉解剖结构方面的价值

目的:探讨320排动态容积CT在评价冠状动脉解剖结构方面的价值,阐述其在CTA扫描方面的优势,并分析其对冠状动脉造影(coronary angiography,CAG)及介入治疗(percutaneous coronary intervention,PCI)的临床指导意义。方法:行320排动态容积扫描的冠状动脉CTA受检者中CTA图像未发现病变且图像质量为1级者70例,均测量其左冠状动脉主干、右冠状动脉、左前降支及左回旋支开口处的内径,左、右冠状动脉的开口位置、开口角度,左前降支与左回旋支之间角度及左主干长度,并按性别分组,行统计学分析。结果:1左冠状动脉主干、右冠状动脉、左前降支及左回旋支开口处的内径平均值分别为(4.10±0.80)mm、(3.52±0.69)mm、(3.43±0.72)mm及(2.84±0.77)mm。其中,男性平均值分别为(4.25±0.80)mm、(3.78±0.68)mm、(3.54±0.75)mm及(3.06±0.83)mm;女性平均值分别为(3.91±0.79)mm、(3.18±0.53)mm、(3.30±0.66)mm及(2.54±0.58)mm。2左、右冠状动脉起始处与升主动脉之间夹角分别为110.13°±15.04°、47.49°±17.19°。其中,男性平均值分别为108.42°±17.25°、45.57°±17.07°;女性平均值分别为112.41°±11.33°、50.05°±17.30°。左前降支与左回旋支之间夹角平均为72.70±30.88°,其中男性为74.18°±31.04°;女性为70.74°±31.08°。3左、右冠状动脉开口位置:位于窦内者分别占78.57%、81.43%,位于窦管结合处者分别占15.71%、14.29%,位于窦外者分别占5.72%、4.29%。4左主干长度平均为(10.49±4.08)mm。其中男性平均为(10.63±4.48)mm;女性平均为(10.29±3.53)mm。5冠状动脉变异情况:左、右冠状动脉开口高位者各1例;双开口10例;右冠状动脉缺如1例;心肌桥9例;冠状动脉瘘1例。结论:320排动态容积CT可清晰显示冠状动脉正常解剖结构及变异情况,对于指导CAG及PCI有重要临床意义。     

Automatic quantification of subcutaneous and visceral adipose tissue from whole‐body magnetic resonance images suitable for large cohort studies

Purpose:

To develop an automated method with which to distinguish metabolically different adipose tissues in a large number of subjects using whole‐body magnetic resonance imaging (MRI) datasets for improving the understanding of chronic disease risk predictions associated with distinct adipose tissue compartments.

Materials and Methods:

In all, 314 participants were scanned using a 1.5T MRI‐scanner with a 2‐point Dixon whole‐body sequence. Image segmentation was automated using standard image processing techniques and knowledge‐based methods. Abdominal adipose tissue was separated into subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) by statistical shape models. Bone marrow was removed to provide a more accurate measurement of adipose tissue. To assess segmentation accuracy, ground‐truth segmentations in 52 images were performed manually by one operator. Due to the high effort of manual delineation, manual segmentation was limited to seven slices per volume.

Results:

Volumetric differences were 3.30 ± 2.97% and 6.22 ± 5.28% for SAT and VAT, respectively. The systematic error shows an overestimation of 4.22 ± 7.01% for VAT and 0.37 ± 4.45% for SAT. Coefficients‐of‐variation from repeated measurements were: 3.50 ± 2.93% for VAT and 0.35 ± 0.26% for SAT. The approach of removing bone marrow worked well in most body regions. Only occasionally the method failed for knees and/or shinbone, which resulted in an overestimation of SAT by 3.14 ± 1.45%.

Conclusion:

We developed a fully automatic process to assess SAT and VAT in whole‐body MRI data. The method can support epidemiological studies investigating the relationship between excess body fat and chronic diseases. J. Magn. Reson. Imaging 2012; 36:1421–1434. © 2012 Wiley Periodicals, Inc.     

Body composition analysis of obesity and hepatic steatosis in mice by relaxation compensated fat fraction (RCFF) MRI

Purpose:

To develop and validate a quantitative magnetic resonance imaging (MRI) methodology for phenotyping animal models of obesity and fatty liver disease on 7T small animal MRI scanners.

Materials and Methods:

A new MRI acquisition and image analysis technique, relaxation‐compensated fat fraction (RCFF), was developed and validated by both magnetic resonance spectroscopy and histology. This new RCFF technique was then used to assess lipid biodistribution in two groups of mice on either a high‐fat (HFD) or low‐fat (LFD) diet.

Results:

RCFF demonstrated excellent correlation in phantom studies (R² = 0.99) and in vivo compared to histological evaluation of hepatic triglycerides (R² = 0.90). RCFF images provided robust fat fraction maps with consistent adipose tissue values (82% ± 3%). HFD mice exhibited significant increases in peritoneal and subcutaneous adipose tissue volumes in comparison to LFD controls (peritoneal: 6.4 ± 0.4 cm³ vs. 0.7 ± 0.2, P < 0.001; subcutaneous: 14.7 ± 2.0 cm³ vs. 1.2 ± 0.3 cm³, P < 0.001). Hepatic fat fractions were also significantly different between HFD and LFD mice (3.1% ± 1.7% LFD vs. 27.2% ± 5.4% HFD, P = 0.002).

Conclusion:

RCFF can be used to quantitatively assess adipose tissue volumes and hepatic fat fractions in rodent models at 7T. J. Magn. Reson. Imaging 2012;35:837–843. © 2011 Wiley Periodicals, Inc.     

3.0‐T MR‐guided focused ultrasound for preoperative localization of nonpalpable breast lesions: An initial experimental ex vivo study

Purpose

To compare the accuracy of magnetic resonance‐guided focused ultrasound (MRgFUS) with MR‐guided needle‐wire placement (MRgNW) for the preoperative localization of nonpalpable breast lesions.

Materials and Methods

In this experimental ex vivo study, 15 turkey breasts were used. In each breast phantom an artificial nonpalpable “tumor” was created by injecting an aqueous gel containing gadolinium. MRgFUS (n = 7) was performed with the ExAblate 2000 system (InSightec). With MRgFUS the ablated tissue changes in color and increases in stiffness. A rim of palpable and visible ablations was created around the tumor to localize the tumor and facilitate excision. MRgNW (n = 8) was performed by MR‐guided placement of an MR‐compatible needle‐wire centrally in the tumor. After surgical excision of the tumor, MR images were used to evaluate tumor‐free margins (negative/positive), minimum tumor‐free margin (mm), and excised tissue volume (cm³).

Results

With MRgFUS localization no positive margins were found after excision (0%). With MRgNW two excision specimens (25%) had positive margins (P = 0.48). Mean minimum tumor‐free margin (±SD) with MRgFUS was significantly larger (5.5 ± 2.4 mm) than with MRgNW (0.9 ± 1.4 mm) (P < 0.001). Mean volume ± SD of excised tissue did not differ between MRgFUS and MRgNW localization, ie, 44.0 ± 9.4 cm³ and 39.5 ± 10.7 cm³ (P = 0.3).

Conclusion

The results of this experimental ex vivo study indicate that MRgFUS can potentially be used to localize nonpalpable breast lesions in vivo. J. Magn. Reson. Imaging 2009;30:884–889. © 2009 Wiley‐Liss, Inc.     

Time after excision and temperature alter ex vivo tissue relaxation time measurements

Previously unreported effects of tissue storage were recently observed in the authors' experimental magnetic resonance (MR) studies. To evaluate the effect of elapsed time after excision and storage temperature on tissue relaxation time measurements, tissue samples from the liver, pancreas, kidney, testis, spleen, and brain were obtained in rats. T1 and T2 were first measured within 5 minutes of excision, and between subsequent measurements, tubes were kept in a water bath at 40°C, at room temperature (28°C), or in an ice bath (4°C). Cellular and organellar integrity was assessed with electron microscopy and correlated with the MR findings. At 40°C (20-MHz spectrometer), the T1 of liver decreased from 280 msec ± 8 to 212 msec ± 10 during the first 60 minutes; the T1 of pancreas decreased from 276 msec ± 3 to 208 msec ± 2. Other tissues showed less than a 5% decrease in T1. T2 changes were smaller than T1 changes in all tissues. Electron microscopy of pancreatic acinar cells showed postmortem changes in mitochondria evolving over the first 60 minutes after death. Manganese loading experiments implicated mitochondrial manganese stores in the observed enhanced postmortem decrease in T1. This study calls into question reported relaxation time data for liver and pancreas. MR studies of excised tissues must account for time and temperature to prevent systematic experimental errors.     

巨噬细胞胆碱能通路对急性缺糖缺氧性肾小管细胞损伤的影响

目的 探讨胆碱能通路对急性缺糖缺氧性肾小管细胞损伤的影响.方法 分离培养大鼠肾内巨噬细胞,构建巨噬细胞与肾小管上皮细胞共培养体系及缺糖缺氧(OGD)细胞模型,据处理不同将细胞分为OGD组、乙酰胆碱(ACh 100μmol/L)+OGD组和ACh+加兰他敏(Gal 10μmol/L)+OGD组.采用ELISA法检测各组上清液肿瘤坏死因子α(TNF-α)、白细胞介素-1β(IL-1β)和IL-10的表达;MTT法检测肾小管细胞活力;RT-qPCR及Western blotting检测胆碱酯酶(AChE)mRNA和蛋白表达;比色法检测AChE活性.结果 ACh+OGD组TNF-α和IL-1β水平均低于OGD组,加入Gal之后,TNF-α和IL-1β水平进一步下降;ACh+OGD组肾小管活力高于OGD组,加入Gal之后,肾小管活力进一步增强,差异有统计学意义(P<0.05或P<0.01).3组之间巨噬细胞AChE mRNA和蛋白表达差异均无统计学意义(P>0.05).与OGD组比较,ACh+OGD组与ACh+Gal+OGD组肾小管细胞活力减弱,但ACh+OGD组与ACh+Gal+OGD组间差异无统计学意义(P=0.368).结论 ACh和Gal可抑制肾脏巨噬细胞分泌炎性介质并抑制胆碱酯酶活性,减轻急性缺氧性肾小管细胞损伤.调控巨噬细胞的胆碱能通路可能是未来急性缺氧性肾损伤的治疗方向.     

MR imaging features of spindle cell lipoma

Objective

To assess the MR imaging features of spindle cell lipomas (SCL) and to compare these appearances directly with the histopathological findings.

Materials and methods

A retrospective review of our soft tissue tumor database was performed. This yielded 1,327 histologically proven lipomas, of which 25 were confirmed as being SCLs. Fourteen of the 25 patients had MR examinations available for review and only these patients were included in our study. Lesions were assessed at MR examination for the degree of internal fat signal content with grade 0 representing 0 % fat signal and grade 4 100 % fat signal. The degree of fat suppression and contrast-enhancement pattern were also recorded. The excision specimens were independently reviewed by a consultant histopathologist. The histology specimens were assessed for the amount of internal fat and non-adipose tissue and graded using the same scale applied for the imaging. Where core needle biopsy (CNB) was performed, the CNB specimens were also examined for positive features of SCL.

Results

In our study, 93 % (13/14) of our patients were male and the average age was 58 years. 65 % (9/14) of the lesions presented in the upper back, shoulder, or neck. All lesions were subcutaneous. 35 % (5/14) of the SCLs demonstrated grade 3 (>75 %) or grade 4 (100 %) fat signal on MR examination. 35 % (5/14) of the lesions had grade 2 (25–75 %) fat signal and 29 % (4/14) of the lesions demonstrated grade 0 (0 %) or grade 1 (<25 %) fat signal. 43 % (6/14) of lesions demonstrated homogenous fat suppression, 28 % (4/14) showed focal areas of high internal signal, and 28 % (4/14) had diffuse internal high signal on fluid-sensitive fat-saturated sequences. 86 % (6/7) of the cases demonstrated septal/nodular enhancement. The diagnosis was evident on the CNB specimen in 100 % (9/9) cases. The histopathology fat content grade was in agreement with the imaging grade in 86 % (12/14) cases.

Conclusions

The internal signal pattern of SCL can range broadly, with low fat content lesions seen almost as commonly as intermediate and high fat content lesions. We also found that the fat:non-fat internal MR signal pattern of these lesions is accurately reflected in their composition at histology.     

Invited. Brain edema development after MRI-guided focused ultrasound treatment

The aim of this study was to investigate a potential technique for image-guided minimally invasive neurosurgical interventions. Focused ultrasound (FUS) delivers thermal energy without an invasive probe, penetrating the dura mater, entering through the cerebrospinal fluid (CSF) space, or harming intervening brain tissue. We applied continuous on-line monitoring by MRI to demonstrate the effect of the thermal intervention on the brain tissue. For this, seven rabbits had a part of their skull removed to create access for the FUS beam into the brain through an acoustic window of 11 mm in diameter. Dura was left intact and skin was sutured. One week later, the rabbits were sonicated for 3 seconds with 21 W acoustic power, and the FUS focus was visualized with a temperature-sensitive T1-weighted MRI pulse sequence. The tissue reaction was documented over 7 days with T2-weighted images of the brain. The initial area of the central low signal intensity in the axial plane was .4 ± .3 mm², and for the bright hyperintensity surrounding the lesion, it was 2.3 ± .6 mm² (n = 7). In the coronal plane, the corresponding values were .4 ± .1 mm² and 3.4 ± .9 mm² (n = 5). The developing brain edema culminated 48 hours later and thereafter diminished during the next 5 days. Histology revealed a central necrosis in the white matter surrounded by edematous tissue with inflammatory cells. In summary, the image-guided thermal ablation technique described here produced a relatively small lesion in the white matter at the targeted location. This was accomplished without opening the dura or the need for a stereotactical device. MRI allowed on-line monitoring of the lesion setting and the deposition of thermal energy and demonstrated the tissue damage after the thermal injury.     

A new approach towards improved visualization of myocardial edema using T2-weighted imaging: a cardiovascular magnetic resonance (CMR) study

Purpose:

To compare T2‐weighted cardiovascular magnetic resonance (CMR) imaging with AASPIR (asymmetric adiabatic spectral inversion recovery) and STIR (short T1 inversion recovery) for myocardial signal intensity, image quality, and fat suppression.

Materials and Methods:

Forty consecutive patients (47 ± 16 years old) referred by cardiologists for CMR‐based myocardial tissue characterization were scanned with both STIR and AASPIR T2‐weighted imaging approaches. Signal intensity of left ventricular myocardium was normalized to a region of interest generating a signal‐to‐noise ratio (SNR). In six patients with regional edema on STIR the contrast‐to‐noise ratio (CNR) was assessed. Two independent observers used a scoring system to evaluate image quality and artifact suppression. Six healthy volunteers (three males, 32 ± 7 years) were recruited to compare fat suppression between AASPIR and STIR.

Results:

SNR of AASPIR was greater than STIR for basal (128 ± 44 vs. 83 ± 40, P < 0.001), mid‐ (144 ± 65 vs. 96 ± 39, P < 0.01), and apical (145 ± 59 vs. 105 ± 35, P < 0.05) myocardium. Improved image quality and greater suppression of artifacts was demonstrated with AASPIR. In patients with regional edema, CNR increased by 49% with AASPIR, while SNR of pericardial fat did not differ (44 ± 39 vs. 33 ± 30, P > 0.05).

Conclusion:

Our findings support the implementation of an AASPIR‐based approach for T2‐weighted imaging due to improved pericardial fat suppression, image quality, and artifact suppression with greater CNR and SNR. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

The effect of high‐intensity training on mitochondrial fat oxidation in skeletal muscle and subcutaneous adipose tissue

High‐intensity interval training (HIT) is known to increase mitochondrial content in a similar way as endurance training [60–90% of maximal oxygen uptake (VO_2peak)]. Whether HIT increases the mitochondria's ability to oxidize lipids is currently debated. We investigated the effect of HIT on mitochondrial fat oxidation in skeletal muscle and adipose tissue. Mitochondrial oxidative phosphorylation (OXPHOS) capacity, mitochondrial substrate sensitivity (K_m^app), and mitochondrial content were measured in skeletal muscle and adipose tissue in healthy overweight subjects before and after 6 weeks of HIT (three times per week at 298 ± 21 W). HIT significantly increased VO_2peak from 2.9 ± 0.2 to 3.1 ± 0.2 L/min. No differences were seen in maximal fat oxidation in either skeletal muscle or adipose tissue. K_m^app for octanoyl carnitine or palmitoyl carnitine were similar after training in skeletal muscle and adipose tissue. Maximal OXPHOS capacity with complex I‐ and II‐linked substrates was increased after training in skeletal muscle but not in adipose tissue. In conclusion, 6 weeks of HIT increased VO_2peak. Mitochondrial content and mitochondrial OXPHOS capacity were increased in skeletal muscle, but not in adipose tissue. Furthermore, mitochondrial fat oxidation was not improved in either skeletal muscle or adipose tissue.