Brain perfusion CT for acute stroke using a 256-slice CT: improvement of diagnostic information by large volume coverage

Objectives  

To compare a 256-slice CT with a simulated standard CT for brain CT perfusion (CTP).     

256层螺旋CT脑灌注成像在急性脑缺血中的应用:大容量数据提供更多诊断信息

目的比较256层螺旋CT脑灌注成像(CTP)与模拟标准CT(SDCT)脑灌注成像的差异。方法51例病人用256层螺旋CT扫描获得CTP影像(探测器数128,Z-轴飞跃,探测器宽度8cm,80kV,120mAs,20次测定,1帧/0.25s)。比较灰、白质的信噪比(SNR)。灌注图评价包括低灌注区域及对应对侧区域的脑血流量(CBF)、脑血容量(CBV)和平均通     

Treatment of persistent extraarticular infection using a temporary cement spacer on the tibia after ACL reconstruction

Postoperative infection after anterior cruciate ligament (ACL) reconstruction is an uncommon but serious complication. Although several treatments for intraarticular infection have been reported, no report has been recorded on the treatment of persistent extraarticular infections. The authors experienced reconstructed graft removal due to a refractory extraarticular infection on tibia. Early ACL reimplantation was performed using a temporary cement spacer containing antibiotics and a irradiated bone patellar tendon bone allograft.     

Simple quantification of brain perfusion SPECT with IMP using a large field gamma camera

We have developed a simple method to quantitate brain perfusion SPECT with N-isopropyl-p-[123I]iodoamphetamine (IMP). After an intravenous bolus injection of IMP, serial dynamic images of the brain and the lung were obtained every 5 sec for 2 min, followed by a SPECT scan at 20 min. Based on the assumption of IMP as chemical microspheres, fractional uptake (FU) of IMP in the brain was calculated from the time-activity curves of the total brain and the total lungs. FU showed a strong positive correlation with inverse of the body surface area which was calculated from the height and weight of the individual subject, suggesting that FU is influenced by cardiac output. Quantification of IMP brain perfusion SPECT was attempted with FU and estimated cardiac output in each subject, providing an index of regional cerebral blood flow. Compared with PET measurement of regional cerebral blood flow, the present method tended to overestimate the flow values. This method has a great advantage that it can be applied in many institutions having large field gamma cameras. However, the accuracy of the measurement may be limited in the tall subjects and in the cases with cardiopulmonary diseases, and further investigation is required to clarify the usefulness and limitation of this approach.     

Evaluation of field dental equipment in a deployment environment

Dental officers and technicians must have reliable, durable, well-performing field dental equipment to enable them to provide dental care to deployed troops in operational environments. Unfortunately, no organized program exists to test such equipment before its purchase and use in the field. This article presents the results of a project conducted by the Naval Institute for Dental and Biomedical Research and the Air Force Dental Evaluation and Consultation Service to evaluate commercially available field dental equipment through laboratory testing and clinical-user evaluations in theater. The purpose of this 2-year project was to identify the best-performing and most cost-effective field dental equipment for possible future procurement. Initial laboratory testing was performed at the Naval Institute for Dental and Biomedical Research, and the equipment was then shipped to Kuwait for in-theater environmental and clinical-user testing. A seven-member scientific team of military dental officers and technicians was deployed for 1 month to perform in-theater testing under regional environmental conditions and to coordinate clinical-user evaluations. The testing provided beneficial results by identifying equipment that performed properly and equipment that exhibited shortcomings serious enough to render it inadequate for operational use. It is recommended that the project serve as a model for future testing and evaluation of medical/dental equipment by all of the military services.     

Robust water/fat separation in the presence of large field inhomogeneities using a graph cut algorithm

Water/fat separation is a classical problem for in vivo proton MRI. Although many methods have been proposed to address this problem, robust water/fat separation remains a challenge, especially in the presence of large amplitude of static field inhomogeneities. This problem is challenging because of the nonuniqueness of the solution for an isolated voxel. This paper tackles the problem using a statistically motivated formulation that jointly estimates the complete field map and the entire water/fat images. This formulation results in a difficult optimization problem that is solved effectively using a novel graph cut algorithm, based on an iterative process where all voxels are updated simultaneously. The proposed method has good theoretical properties, as well as an efficient implementation. Simulations and in vivo results are shown to highlight the properties of the proposed method and compare it to previous approaches. Twenty‐five cardiac datasets acquired on a short, wide‐bore scanner with different slice orientations were used to test the proposed method, which produced robust water/fat separation for these challenging datasets. This paper also shows example applications of the proposed method, such as the characterization of intramyocardial fat. Magn Reson Med, 2010. © 2009 Wiley‐Liss, Inc.     

经尿道气化电切治疗重度前列腺增生症

目的探讨重度前列腺增生症(BPH)的治疗方法。 方法应用经尿道前列腺电气化术(TUVP)加经尿道前列腺电切术(TURP)联合治疗重度BPH患者60例。 结果 手术时间50-90 min,平均75 min,平均切除前列腺组织70 g。仅发生1例先兆电切综合症。术后平均6天拔管,自行排尿通畅。IPSS由术前平均25.5分下降至术后平均7.0分(P<0.001),最大尿流率(Qmax)由术前平均5.2 ml/s升至术后平均18.9 ml/s(P<0.001),剩余尿量由术前平均100 ml降至术后平均15 ml。术后继发性出血1例,一过性尿失禁1例。 结论TUVP加TURP联合治疗BPH兼有两者优点,是彻底治疗重度BPH安全、有效的方法。     

Stability of ischemic core volume during the initial hours of acute large vessel ischemic stroke in a subgroup of mechanically revascularized patients

Introduction

This study aimed to relate growth of the infarct core with time to recanalization in patients receiving mechanical recanalization in whom the time of recanalization is known.

Methods

We analyzed data from patients with anterior circulation acute ischemic stroke who underwent mechanical recanalization. Demographic and angiographic characteristics, initial apparent diffusion coefficient (ADC) infarct volume, time-to-peak defect volume, revascularization grade, 24–48 h nonenhanced computed tomography (CT) infarct volume, symptom onset to recanalization time, diffusion-weighted imaging to recanalization time, and discharge National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) scores were compared between minimal and substantial infarct growth groups. Substantial infarct growth was defined as an increase of infarct volume >10 cm³ assessed by subtracting initial ADC infarct core volume from infarct volume at 24–48 h CT.

Results

Of 25 patients, 9 had minimal infarct growth (median 0 cm³, interquartile range (IQR) ?3 to 5 cm³) and 16 had substantial infarct growth (median 103 cm³, IQR 48–132 cm³). Patients with minimal infarct growth had a median time from symptom onset to recanalization of 329 min (IQR 314–412 min) and a median time from imaging to recanalization of 231 min (IQR 198–309 min). On univariate analysis, minimal infarct growth was related to male gender (p?=?0.04), smaller initial ADC volume (p?=?0.04), higher recanalization grade (p?<?0.001), and lower discharge NIHSS (p?=?0.04) and mRS grades (p?=?0.04).

Conclusion

There was no or minimal infarct core growth in at least one third of patients despite an exceptionally long median time from magnetic resonance imaging to recanalization of almost 4 h.     

HVHF治疗时机对SAP并发急性肾损伤疗效的影响

目的探讨以RIFLE标准衡量高容量血液滤过（HVHF）治疗重症急性胰腺炎（SAP）并发急性肾损伤的治疗时机及其对疗效的影响。方法回顾性分析本院自2006年1月～2010年12月行HVHF治疗的45例SAP患者,采用RIFLE标准分成A组（AKIⅠ期）、B组（AKIⅡ期）、C组（AKIⅢ期）。以AKI分期作为HVHF治疗的时机,对比分析各组的病死率、ICU住院时间、机械通气时间、连续血液滤过治疗时间,并将HVHF治疗前和治疗24 h后的APACHEⅡ和SOFA评分、血浆IL-6、氧合指数、血浆肌酐（Cr）、平均动脉压（MAP）等结果进行比较。结果 （1）C组HVHF治疗前APACHEⅡ和SOFA评分、血浆IL-6及病死率均明显高于A、B两组（P〈0.01）;（2）A、B两组HVHF治疗前APACHEⅡ评分、SOFA评分及病死率没有差别（P〉0.05）,但B组HVHF治疗前IL-6浓度以及ICU住院时间、机械通气时间、连续血液滤过治疗时间明显高于或长于A组（P〈0.05或P〈0.01）;（3）3组HVHF治疗24 h后血浆IL-6、氧合指数、Cr、MAP均明显改善,但C组IL-6仍高于A、B两组（P〈0.01）,B组IL-6仍高于A组（P〈0.01）;A、B两组HVHF治疗24 h后APACHEⅡ和SOFA评分显著降低（P〈0.01）,C组变化无显著性差别（P〉0.05）。结论 HVHF能有效辅助治疗SAP;RIFLE标准及IL-6对判断预后有指导意义;早期（AKIⅠ、Ⅱ期）行HVHF可明显改善SAP的预后,而AKIⅠ期行HVHF的疗效更好。     

Functional MR imaging using gradient-echo echo-planar imaging in the presence of large static field inhomogeneities

At 1.5 T, the field strength of most clinical MR imagers, gradient-echo Imaging Is the primary imaging method for measuring brain activation, as such sequences are highly sensitive to changes in blood oxygenation or T2* effects. Unfortunately, gradient-echo sequences are also extremely sensitive to magnetic field inhomogeneities, and this sensitivity has precluded examination of regions of cortex near field inhomogeneities with functional MR imaging. This article presents a gradient-echo echo-planar imaging method that uses variable amplitude scaling on the slice-select refocusing lobe to generate images compensated for static field inhomogeneities. A technique for constructing composite Images to be used in statistical tests for activation is also presented. The method is shown to produce clean activation maps in the presence of large static field inhomogeneities. The technique retains the sensitivity of gradient- echo imaging to changes in blood oxygenation while removing the sensitivity to large static field inhomogeneities.     

Unequal narrowing of the visual field in a +Gz environment.

Anecdotally, the existence of individuals who experience an unequal loss of peripheral vision (left versus right) under sustained +Gz acceleration is well known. However, there is little mention or explanation of the etiology in the literature. Only recently has there been a surge of interest in this phenomenon. The operational significance is more important. The most common interpretations for this phenomenon are unequal arterial pressure between the left and right blood supplies to the retina (ophthalmic artery, its branch to the retina, the central retinal arteries, the circle of Willis, and the internal carotid artery), and a difference in the intraocular pressure. Two case histories of unequal peripheral light loss (PLL) are discussed. It is possible for a pilot not to be aware of his or her full sequence of PLL and, in an operational environment, lose half the visual field and not realize it. We need more controlled studies to define unequal PLL and to ensure valid centrifuge subject data.     

The design and test of a new volume coil for high field imaging

A major problem in the development of high field (>100 MHz) large volume (>6000 cm³) MR coils is the interaction of the coil with the subject as well as the radiation loss to the environment. To reduce subject perturbation of the coil resonance modes, a volume coil that uses an array of freely rotating resonant elements radially mounted between two concentric cylinders was designed for operation at 170 MHz. Substantial electromagnetic energy is stored in the resonant elements outside the sample region without compromising the efficiency of the overall coil. This stored energy reduces the effect of the subject on the circuit and maintains a high Q, facilitating the tuning and matching of the coil. The unloaded Q of the coil is 680; when loaded with a head, it was 129. The ratio of 5.3 of the unloaded to loaded Q supports the notion that the efficiency of the coil was maintained in comparison with previous designs. The power requirement and signal-to-noise performance are significantly improved. The coil is tuned by a mechanism that imparts the same degree of rotation on all of the elements simultaneously, varying their degree of mutual coupling and preserving the overall coil symmetry. A thin radiofrequency shield is an integral part of the coil to reduce the radiation effect, which is a significant loss mechanism at high fields. MR images were collected at 4T using this coil design with high sensitivity and B₁, homogeneity.     

大型综合性医院急性中毒患者的流行病学特点

目的 研究大型综合性医院急性中毒患者的流行病学特点.方法 采用前瞻性研究方法,对2005年1月～2006年12月在急诊科就诊的急性中毒患者的性别、年龄、职业、中毒时间、中毒原因、毒物种类、毒物侵入途径、急诊诊断、急诊处理情况、转归等进行调查分析.结果 急性中毒患者共315例,占急诊患者总数的2.33‰,男女比为1∶0.84,主要集中于20～29岁年龄组(占35.9%);毒物种类以酒精为主(占38.4%),其他依次为药物、食物、其他化学物质、农药中毒等;中毒时间呈无规律性波动,以1～2月、6～7月和11～12月相对较多;毒物进入人体最常见的途径是经消化道摄入(占85.1%);中毒患者的职业以专业技术人员为主(占21.0%),其他依次为农民及民工、个体业者、家务及无业人员等;98.1%患者治愈出院,1.9%死亡.结论 青年人与专业技术人员是大城市急性中毒的高危人群,毒物种类以酒精、药物、食物和其他化学物质等为主,中毒途径主要为消化道摄入,中毒季节无明显规律性.     

急性跟腱撕裂的低场MRI诊断

目的探讨低场MRI在急性跟腱损伤中的诊断价值和表现。方法分析29例有踝关节外伤病史、经临床或手术证实且MRI资料完整的跟腱完全撕裂或部分撕裂患者,总结其特征性MRI表现。结果 MRI诊断跟腱完全撕裂10例,MRI特征性表现为肌腱增粗、形态不规则,肌腱束连续性完全中断,肌腱断端回缩呈"杵"状或交错呈"毛刷"状改变,在T₁WI、T₂WI上其内呈混杂高信号。部分性撕裂19例,MRI表现为跟腱增粗,前后径与宽径的比例变大,在T₁WI、T₂WI上肌腱内局限性高信号,肌腱束部分毛糙、不规则,但在矢状位至少有1层面连续。结论低场MRI能清晰显示跟腱形态及内部结构,可以准确诊断撕裂的部位和程度,为临床手术治疗提供准确的依据。     

A special treatment couch for irradiation of a large body volume.

A special treatment couch has been designed for deployment of a greatly extended treatment distance for irradiation of a large body volume, particularly an irregular one which requires shielding. The basic unit is a commercial hydraulic lift table to which an appropriate plywood top and small wheels were added. Its advantage is its capacity to transfer very ill and disabled patients quickly and safely from a wheelchair, portable hospital litter, or bed.     

Activity measurement of 85Kr diluted by a large volume balloon technique

The National Metrology Institute of Japan (NMIJ) participated in the CCRI(II) Key-comparison of ⁸⁵Kr activity measurement. The absolute internal gas-counting method was used, with a set of proportional counters of different length. The original ⁸⁵Kr gas was diluted by a factor of 2×10⁵ in order to achieve the suitable activity concentration for the proportional counters. A new dilution method was introduced, based on a large-volume balloon and gravimetric determination of the dilution volume with small uncertainties.