In vivo high‐resolution imaging of the injured rat spinal cord using a 3.0T clinical MR scanner

Purpose

To investigate the feasibility of obtaining high‐resolution MR images for the detection of pathological changes occurring in the injured rat spinal cord with a routine clinical 3.0T imaging system.

Materials and Methods

Adult female Fischer 344 rats received thoracic spine contusion injuries. In vivo MR imaging was performed on days 1 and 43 postinjury with a clinical head 3.0T imaging system equipped with a dedicated small animal 4‐channel phased array spine surface coil using T2‐weighted turbo spin‐echo and T1‐weighted spin‐echo sequences.

Results

The acquired images provide good spatial resolution allowing reliable gray/white matter differentiation in the intact spinal cord as well as detection of hemorrhage, edema, and cystic degenerative changes in the injured rat spinal cord as confirmed by correlation with structural alterations in histological sections.

Conclusion

Results from the present study demonstrate that a routine clinical MR imaging system can be employed for noninvasive analysis of pathological changes occurring in the injured rat spinal cord and thus might represent a more broadly available, powerful tool to monitor the effects of experimental therapeutic interventions in vivo. J. Magn. Reson. Imaging 2009;29:725–730. © 2009 Wiley‐Liss, Inc.     

早期乳腺癌保乳术后全乳腺调强放疗的临床分析

目的 观察分析早期乳腺癌保乳术后全乳腺调强放疗剂量学优势、临床疗效及不良反应。方法 搜集2004年10月至2005年8月收治的103例早期乳腺癌保乳术后患者,比较全乳腺逆向调强和常规切线野治疗计划靶区的均匀性和心脏、肺受照剂量,以及调强放疗临床不良反应、美容效果及疗效。结果 调强放疗、常规放疗临床靶区的95%~107%处方剂量的平均体积百分比分别为95.8%±4.90%、84.0%±20.7% (t=9.60,P<0.01);同侧受照剂量>20 Gy正常肺组织占全肺体积(V₂₀)的百分比分别为15.70%±4.64%、23.11%±7.88% (t=-13.3,P<0. 01);63例左侧乳腺癌患者心脏V₃₀分别为4.44%±3.93%、15.55%±10.89% (t=-11.3,P<0. 01)。1、2年美容效果优良率均为100%。1、2、3年局部控制率分别为99%、99%、98%;1、2、3年无瘤生存率分别为99%、99%、96%。放疗结束时急性皮肤反应1级98例,2级5例。结论 乳腺癌保乳术后全乳腺调强与常规切线野照射相比,能明显改善靶区剂量分布、保护周围正常组织;局部疗效好,临床不良反应小。     

深吸气屏气技术对左侧乳腺癌术后包含内乳淋巴结调强放疗的心脏剂量学影响

目的 探索左侧乳腺癌术后包含内乳淋巴结调强放疗时,实施深吸气屏气技术(DIBH)对心脏剂量 学的影响。方法 观察2021年10月至2022年7月蚌埠医学院第一附属医院23例左侧乳腺癌术后行包含内乳淋巴结调强放疗(IMRT)患者心脏和冠状动脉左前降支(LAD)在DIBH时相上剂量学参数的变化,并分析其实施效果的潜在影响因素。结果 与自由呼吸(FB)相比,DIBH状态下心脏体积缩小18% (t=10.47,P＜0.001)、左肺体积扩张42%(t=-14.55,P＜0.001),心脏及LAD的平均剂量D_mean、最大剂量D_max以及剂量体积参数V₅ ~ V₃₀均明显降低,差异具有统计学意义(t=-13.38 ~ -3.30,P＜0.05);相关性分析显示,左肺扩张的相对比值与心脏剂量减少的相对比值呈正相关(r=0.82,P＜0.001),患者年龄与心脏剂量减少的相对比值呈负相关(r=-0.56,P=0.005)。结论 本研究明确了左侧乳腺癌术后包含内乳淋巴结IMRT时实施DIBH,可有效地降低心脏及LAD的剂量,年龄和肺活量可能是DIBH实施效果的影响因素。     

中下段食管癌调强放疗布野方案剂量学比较

目的 分析中下段食管癌放疗中5野调强计划与7野调强计划的差异,寻找布野最佳方案.方法 分别为接受调强放射治疗的12例中下段食管癌患者设计5野调强计划与7野调强计划,计划设计中要求95％的计划靶体积达到处方剂量.在每个病例中,分别比较两种计划的剂量体积直方图统计数据、剂量均匀指数、剂量适形指数.结果 两种方案中,7野调强计划的靶区剂量适形度较好(t=2.681,P＜0.05);两种方案的剂量均匀指数、脊髓受照剂量、心脏受照剂量之间的差异无统计学意义;5野调强计划的双肺V5、V10、V15较低(t=-7.938、-12.055和4.859,P均＜0.05).结论 在中下段食管癌放疗中,与7野调强计划相比,5野调强计划可以减少肺部的低剂量受照体积,同时提供可以接受的计划靶体积适形度,有助于减少肺部辐射损伤的发生概率,改善患者生存质量,值得在临床工作中推广应用.     

乳腺癌保乳术后放疗瘤床二维电子线与三维调强补量的疗效比较

目的 比较乳腺癌保乳手术后瘤床电子线二维补量和X射线三维调强补量方法对肿瘤局部控制率及患者生存的影响。方法 回顾性分析485例于北京肿瘤医院接受乳腺癌保乳手术的患者,术后全乳腺照射46~50 Gy/23~25次后,一组患者采用电子线技术,另一组采用X射线调强技术进行瘤床补量放疗,补量剂量均为10~16 Gy/5~8次。结果 全组患者的中位随访时间为96.04个月。X射线调强瘤床补量组的5年和10年无局部复发生存率（LRFS）均为98.4%,明显优于电子线补量组5年的94.2%和10年的93.2%（χ²=4.190,P<0.05）。但两组的总生存率（OS）间无明显差异,X射线组5年和10年的OS率分别为96.7%和95.8 %,电子线组的分别为94.9%和89.4%（P>0.05）。在多因素分析中,年龄≤40岁、腋窝淋巴结有转移及Her-2高表达是LRFS的独立预后因素,而放疗瘤床补量方式不是LRFS和OS的预后因素（P>0.05）。结论 乳腺癌保乳手术后,X射线调强放疗较电子线二维放疗在瘤床补量治疗上有更好的肿瘤局部控制率,但对患者生存无明显影响。     

Performance of a miniature high‐temperature superconducting (HTS) surface coil for in vivo microimaging of the mouse in a standard 1.5T clinical whole‐body scanner

The performance of a 12‐mm high‐temperature superconducting (HTS) surface coil for in vivo microimaging of mice in a standard 1.5T clinical whole‐body scanner was investigated. Systematic evaluation of MR image quality was conducted on saline phantoms with various conductivities to derive the sensitivity improvement brought by the HTS coil compared with a similar room‐temperature copper coil. The observed signal‐to‐noise ratio (SNR) was correlated to the loaded quality factor of the radio frequency (RF) coils and is theoretically validated with respect to the noise contribution of the MR acquisition channel. The expected in vivo SNR gain was then extrapolated for different anatomical sites by monitoring the quality factor in situ during animal imaging experiments. Typical SNR gains of 9.8, 9.8, 5.4, and 11.6 were found for brain, knee, back, and subcutaneous implanted tumors, respectively, over a series of mice. Excellent in vivo image quality was demonstrated in 16 min with native voxels down to (59 μm)³ with an SNR of 20. The HTS coil technology opens the way, for the first time at the current field strength of clinical MR scanners, to spatial resolutions below 10^–3 mm³ in living mice, which until now were only accessible to specialized high‐field MR microscopes. Magn Reson Med 60:917–927, 2008. © 2008 Wiley‐Liss, Inc.     

小鼠脑损伤相关基因的克隆及表达与生物学功能初步分析

目的克隆1个与小鼠脑损伤早期反应相关的新基因（GBI），并对其功能进行初步分析。方法SMART—RACE技术克隆该新基因全长eDNA；采用生物信息学软件分析其可能的功能结构域和进行序列相似性分析；Northern Blotting分析该基因在小鼠主要组织器官的生理水平的表达。结果该新基因全长eDNA序列为1798bp，含1个编码249个氨基酸残基蛋白质的开放性阅读框。推导蛋白质分子与1个即刻早期蛋白IE175和1个应激相关蛋白RAB21具有部分序列相似性。Northern杂交显示其仅仅在小鼠脑组织有基础水平的表达。结论该基因可能与创伤早期反应的应激信号转导相关，并命名为脑损伤相关基因GBI（gene related to brain injury，gi1193389811 gb IAF481964．1）。     

小鼠脑损伤相关基因的克隆及表达与生物学功能初步分析

目的 克隆1个与小鼠脑损伤早期反应相关的新基因(GBI),并对其功能进行初步分析.方法 SMART-RACE技术克隆该新基因全长cDNA;采用生物信息学软件分析其可能的功能结构域和进行序列相似性分析;Northern Blotting分析该基因在小鼠主要组织器官的生理水平的表达.结果 该新基因全长cDNA序列为1798bp,含1个编码249个氨基酸残基蛋白质的开放性阅读框.推导蛋白质分子与1个即刻早期蛋白IE175和1个应激相关蛋白RAB21具有部分序列相似性.Northern杂交显示其仅仅在小鼠脑组织有基础水平的表达.结论 该基因可能与创伤早期反应的应激信号转导相关,并命名为脑损伤相关基因GBI(gene related to brain injury,gi|19338981|gb|AF481964.1).     

Radioprotective and radiomitigative effects of BP-C2, a novel lignin-derived polyphenolic composition with ammonium molybdate,in two mouse strains exposed to total body irradiation

Purpose: There remains an unmet medical need for radioprotective and mitigative agents. BP-C2 is a novel lignin-derived polyphenolic composition with ammonium molybdate, developed as radioprotector/radiomitigator.

Objectives: The present study evaluated BP-C2 for the mitigation of acute radiation syndrome (ARS).

Methods: A total-body irradiation mouse model (TBI, 4.0–8.0?Gy) was used in the study.

Results: In a 30-day survival study, performed in CBA mice, BP-C2, at a dosage of 81.0?mg/kg, improved survival (dose reduction factor (DRF)?=?1.1) and increased the formation of endogenous spleen colony-forming units (CFU). In C57BL/6 mice, BP-C2, when administered daily for 7 days, starting 24?hours after TBI, also improved survival. In animals irradiated with 5.0?Gy, BP-C2 increased the number of CFUs (6.7?±?5.1) compared to the 5.0?Gy placebo group (2.3?±?2.3, p?=?.0245). The number of surviving intestinal crypts was maintained in the 5.0?Gy BP-C2 group (133.7?±?13.9), in contrast to the 5.0?Gy placebo group (124.2?±?10.5, p?Conclusion: BP-C2 mitigates radiation-induced damage in mid-lethal range of radiation doses. Effects are mediated by enhancement of extramedullar hematopoiesis in the spleen and a protective effect on the intestinal epithelium.     

Estimation of brain iron concentration in vivo using a linear relationship between regional iron and apparent transverse relaxation rate of the tissue water at 4.7T

Maps of the apparent transverse relaxation time (T₂^?) were collected on a transaxial plane across the basal ganglia in 54 healthy subjects at 4.7T using a multiecho adiabatic spin‐echo (MASE) imaging sequence. We attempted to quantify the nonhemin iron concentration ([Fe]) in various brain regions in vivo based on the linear relationship between the apparent relaxation rate constant (R₂^? = 1/T₂^?) and regional [Fe], as demonstrated previously in 12 subjects. The calculated [Fe] in five gray matter (GM) regions agreed well with the previously reported regional iron distribution as well as reproduced its age‐dependent change. In particular, a decrease of iron in the thalamus region in subjects over 30 years of age was demonstrated while an upward trend was shown in other regions. Furthermore, the average R₂^? in each GM region in subjects over 30 years of age showed a deviation from the regression line with [Fe] in an identical manner to that obtained in the previous 12 subjects. This strongly suggests that there is a systematic regional factor affecting R₂^?, in addition to iron. Interregional difference in the macromolecular mass fraction (f_M) explained this systematic deviation well. When accounting for f_M in the analysis, the apparent transverse relaxation rate seems to give a significantly better estimation of regional [Fe]. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.     

Noninvasive in vivo MRI detection of neuritic plaques associated with iron in APP[V717I] transgenic mice, a model for Alzheimer's disease.

Transgenic mice overexpressing the London mutant of human amyloid precursor protein (APP[V717I]) in neurons develop amyloid plaques in the brain, thus demonstrating the most prominent neuropathological hallmark of Alzheimer's disease. In vivo 3D T2*-weighted MRI on these mice (24 months of age) revealed hypointense brain inclusions that affected the thalamus almost exclusively. Upon correlating these MRI observations with a panel of different histologic staining techniques, it appeared that only plaques that were positive for both thioflavin-S and iron were visible on the MR images. Numerous thioflavin-S-positive plaques in the cortex that did not display iron staining remained invisible to MRI. The in vivo detection of amyloid plaques in this mouse model, using the intrinsic MRI contrast arising from the iron associated with the plaques, creates an unexpected opportunity for the noninvasive investigation of the longitudinal development of the plaques in the same animal. Thus, this work provides further research opportunities for analyzing younger APP[V717I] mouse models with the knowledge of the final outcome at 24 months of age.     

Design,construction and application of a neutron shield for the treatment of diffuse lung metastases in rats using BNCT

A model of multiple lung metastases in BDIX rats is under study at CNEA (Argentina) to evaluate the feasibility of BNCT for multiple, non-surgically resectable lung metastases. A practical shielding device that comfortably houses a rat, allowing delivery of a therapeutic, uniform dose in lungs while protecting the body from the neutron beam is presented. Based on the final design obtained by numerical simulations, the shield was constructed, experimentally characterized and recently used in the first in vivo experiment at RA-3.     

64层螺旋CT胸痛三联排查扫描的新扫描协议设计与可行性研究：全主动脉、冠状动脉与肺动脉一站式成像

目的:评价64层螺旋CT改良胸痛三联排查(TRO)扫描(覆盖整个主动脉)的图像质量、辐射剂量及其临床价值.方法:连续选取2013年1月-2015年8月行改良TRO扫描的17例患者作为实验组,另连续选取2014年3月-2015年8月行常规TRO扫描的37例患者作为对照组,所有研究对象心率≤70次/分.采用秩和检验与两独立样本t检验比较两组的图像质量、辐射剂量及对比剂剂量.结果:实验组与对照组冠状动脉评分分别为(4.56±0.66)和(4.62±0.56)分(Z=-0.558,P=0.557).实验组与对照组主动脉根部CT值分别为(385.88±42.36)和(364.46±40.62) HU(t=1.748,P=0.091),肺动脉根部CT值分别为(354.29±68.44)和(332.46±49.97) HU(t=1.324,P=0.191).实验组与对照组有效剂量分别为(33.99±9.07)和(24.39±8.70)mSv(t=3.715,P=0.000);实验组与对照组对比剂剂量分别为(145.76±9.71)和(112.62±15.11)mL(t=8.269,P=0.000).结论:改良TRO对于低心率患者是可行且有效的,可以提高64层螺旋CT的适用范围,具有一定临床价值.     

A new method to combine contrast-enhanced magnetic resonance imaging during live ultrasound of the breast using volume navigation technique: a study for evaluating feasibility, accuracy and reproducibility in healthy volunteers

Objectives

To evaluate feasibility, accuracy and reproducibility of combined US-MR of the breast using volume navigation technique.

Subjects and methods

Five healthy females underwent bilateral contrast-enhanced MR (CE-MR) of the breast in supine position, after positioning three couples of markers on the breast. After CE-MR data uploading in the ultrasound (US) database, manual co-registration was obtained during live US of the breast by means of an electromagnetic transmitter positioned near the subject under examination and two electromagnetic sensors were mounted on the transducer bracket. Transmitter and sensors were connected to a position-sensing unit embedded in the US equipment allowing to track probe position and orientation within the electromagnetic field. Live US image were co-registered to the previously loaded breast CE-MR volume by coupling markers. For each subject, two independent radiologists recorded the examination time and verified twice image alignment using five fixed checkpoints. Pair t Student test and Wilcoxon test were used for statistical analysis.

Results

In all subjects US and CE-MR images were successfully combined. The examination time was 10 ± 2 vs. 9 ± 4 min, respectively (p = 0.642; NS). A total of one hundred measurements of images misalignment were performed: the measurements recorded between the two operators were 0.42 ± 0.32 cm and 0.58 ± 0.41 cm (p = 0.161; NS), and 0.50 ± 0.32 cm and 0.56 ± 0.52 cm (p = 0.928; NS), respectively.

Discussion

In our preliminary experience, volume navigation technique appears to be a accurate and reproducible method to combine CE-MR image during unilateral US of the breast.