Ethical considerations in CT angiography

The rapid development and clinical deployment of CT angiography raises several important issues, including assurance of professional competence and technical quality, self-referral, the relative role of radiologists and cardiologists, appropriateness and proper indications, the detection and disposition of unexpected or incidental findings and the concern for the rapidly increasing costs of health care and imaging. These questions are properly addressed within the framework of medical ethics, including principles of beneficence, autonomy and justice.     

Combined MRI and fibreoptic colonoscopy: technical considerations and clinical feasibility

A method of fibre-optic colonoscopy with simultaneous high resolution MRI has been developed to obtain cross-sectional information of the intramural and extramural extent of lesions, for diagnostic and therapeutic purposes. An MR-compatible colonoscope with receiver coil was designed, developed and used in ex vivo studies to scan a section of large bowel in transverse and longitudinal planes with T₁ and T₂ weighted spin-echo sequences. In vivo five patients were followed-up after excision of large bowel cancer. The patients were three men and two women aged 50-77 years, (mean 65.6 years) who were studied on a 0.5 T scanner (Picker Asset, OH, USA). The coil and colonoscope were inserted into the rectum. After routine visual inspection of the colon, T₁ weighted spin-echo images and radio-frequency spoiled gradient-echo images of the bowel wall were obtained. Ex vivo: three layers of bowel wall were identified: an intermediate to high signal-intense mucosa, a high signal intensity layer on T₁ weighting which corresponded to the submucosa, and a low signal intensity muscularis propria. In vivo: On T₁ weighted images three layers could be identified that corresponded to the layers seen on the ex vivo imaging. This pilot study demonstrates that MR colonoscopy is feasible and allows delineation of bowel wall structure, thus providing a useful adjunct to conventional colonscopy.     

低剂量心脏平扫与冠脉CT血管造影在测量心外膜脂肪体积方面具有等效性

目的 分析低剂量心脏平扫检查与冠状动脉CT血管造影（CTA）检查在定量心外膜脂肪体积（EATV）的一致程度。 方法 对临床提示有冠心病征象的208名患者进行低剂量心脏平扫检查及冠状动脉CTA检查,分别在两种检查的图像上测量心外膜脂肪体积,两种检查测量所得心外膜脂肪体积EATV _心脏平扫和EATV_CTA间的相关性采用Pearson相关系数进行评估,采用BlandAltman分析法评价两者的一致性。将患者分为无斑块组及斑块组,比较两组患者EATV _心脏平扫和EATV_CTA差异;通过操作者工作特征曲线评估EATV _心脏平扫和EATV_CTA预测冠状动脉硬化的价值及差异。 结果 低剂量EATV _心脏平扫为103.12±44.01 cm³,EATV_CTA为106.72±44.14 cm³,两者具有显著的相关性（r = 0.955,P< 0.001）;EATV _心脏平扫和EATV_CTA的一致性均数为-3.5,4.8%（10/208）的点落位于95%CI界限以外（95%CI：24.0930~29.2116,P< 0.001）;EATV _心脏平扫和EATV_CTA预测冠状动脉硬化发生的曲线下面积分别为0.601及0.605,差异无统计学意义（P= 0.935）。 结论 低剂量心脏平扫检查与冠状动脉CTA两组检查方法在测量EAT方面具有等效性,对冠状动脉硬化的预测方面两者具有相当的价值。     

Renal magnetic resonance angiography at 3.0 T: technical feasibility and clinical perspectives

The increased signal-to-noise ratio at 3.0 T holds promise for high-spatial resolution renal magnetic resonance angiography (MRA). Today, state-of-the-art renal MRA is feasible with submillimeter isotropic spatial resolution in less than 20 seconds acquisition time with sufficient signal-to-noise ratio. This article explains the fundamentals of 3.0-T imaging that are essential for renal MRA, with a focus on the clinical implications. Protocol and imaging recommendations are given based on the physical principles of 3.0-T imaging and underlined by current clinical cases. Apart from pure morphological imaging, the value of functional renal imaging such as renal flow measurements and renal perfusion measurements for a comprehensive 3.0-T renal MRA protocol is discussed.     

Contrast media volume optimization in high-pitch dual-source CT coronary angiography: feasibility study

To investigate the feasibility of contrast media (CM) volume reduction in dual-source coronary computed tomography angiography high-pitch mode without affecting coronary artery enhancement. Eighty patients were involved in a preliminary experiment with a default injection protocol (60 ml of CM). The age, BMI, test bolus (TB) enhancement peak and the CT values of coronary artery for each patient were recorded and the key factors for determining coronary artery enhancement were investigated. Based on the results of the preliminary experiment, 120 patients were involved in the main experiment with a new injection protocol. For each patient, the CT values and noise of left coronary sinus (LCS), and the distal segment of right coronary artery were measured. In the preliminary experiment, the peak enhancement of TB correlated most strongly with the HU values of coronary artery. Consequently, the new injection protocol was devised to catalog patients into four groups (30, 40, 50 and 60 ml) of CM based on their TB peak enhancement. In the main experiment, the 30 ml CM injection group whose peak attenuation of TB were the highest (30 vs. 40,50,60 ml: 323.0 ± 27.5 vs. 264.2 ± 11.9, 242.1 ± 8.8, 206.2 ± 18.2 HU, p < 0.05), obtained the highest attenuation of LCS (30 vs. 40,50,60 ml: 365.0 ± 41.2 vs. 341.8 ± 40.0, 326.9 ± 34.7, 312.5 ± 38.2 HU p < 0.05). Contrast optimization is feasible in high-pitch DSCT coronary angiography. Certain patients may receive 30 ml of CM without affecting vessel enhancement.     

Erratum to: Pelvic CT angiography in blunt trauma: imaging findings and protocol considerations

The evolution of multi-row detector computed tomography (MDCT) technology has resulted in evolving applications of CT angiography (CTA) in the trauma setting. In patients with significant blunt pelvic injuries, the immediate diagnosis and characterization of vascular injuries are of significant import given their morbidity and mortality in this patient population. The application of MDCT technology, specifically 64MDCT, to pelvic CTA is useful in evaluating for potential vascular injuries and may be integrated into admission trauma imaging in order to triage patients with blunt pelvic trauma to appropriate emergent intervention. This review will discuss the use of pelvic CTA in blunt pelvic trauma and its utility in detecting and characterizing vascular injury, including the differentiation of arterial from venous hemorrhage. Protocol considerations in pelvic CTA using 64MDCT technology will be detailed as well as the integration of pelvic CTA into torso CT trauma protocols.     

腹主动脉瘤超声造影表现与CT血管成像的比较

目的比较腹主动脉瘤超声造影与CT血管成像(CTA)的表现,探讨超声造影(CEUS)在腹主动脉瘤诊断及术后随访中的应用价值。方法采用超声造影检查对18例(术前检查10例,术后复查8例)腹主动脉瘤患者进行术前诊断或术后复查,所有患者均同时行CT血管成像检查。将两种方法诊断术前患者真性动脉瘤、夹层动脉瘤、假性动脉瘤及术后有无内漏情况进行对比研究。结果术前超声造影诊断为真性动脉瘤5例,夹层动脉瘤4例,假性动脉瘤1例;术后随访8例中支架置入及人工血管置换各4例,均未见内漏,与CTA结果一致。结论应用超声造影对腹主动脉瘤进行术前诊断及术后随访,结果和CTA一致,值得推广应用。     

Imaging and identification of brown adipose tissue on CT scan

Two types of adipose tissue (AT) have been described in the field of physiology: white (W) and brown (B) AT. Although WAT is well identified on human imaging, BAT imaging aspect remains to be further explored. The aim of this study was to investigate imaging aspect of BAT and its identification on CT (computed tomography) with iodine‐based contrast media injection. We retrospectively reviewed 464 positron emission tomography (PET)/CT, performed during 21 months on adults younger than 37 years. In 39 cases only, the PET revealed the presence of activated BAT. ROI was placed on both white and brown adipose tissue simultaneously on both PET and CT. Several patients’ characteristics (blood sugar level, gender, age, body mass index) as well as BAT and WAT parameters were assessed. Mean CT densities for WAT and BAT were ?99·5 HU versus ?32·6, mean SUV were 1·38 versus 13·2 and SUVmax were 1·79 versus 16·57, respectively. We found a statistically significant inverse relation between BMI and BAT density. BAT has a higher density than WAT. In this manner, BAT can be misinterpreted as an infiltration of adipose tissue in neoplasic and inflammatory context. Contrast‐enhanced CT scan allows visualization and identification of BAT.     

The feasibility of halfcycle reconstruction in high heart rates in coronary CT angiography using 320-row CT

Our aim was to investigate when halfcycle reconstruction (HCR) was feasible in patients who were predicted to have a heart rate over 65 bpm in coronary CT angiography (CTA) using 320-row CT. Seventy-four patients who underwent multiple heart beat scanning were included. The time to reach 230 HU at the ascending aorta during the bolus tracking scan was recorded (T₂₃₀). HCR image and multicycle reconstruction (MCR) image were reconstructed for each patient. Image quality for each coronary segment was rated on a 3-point scale (3: good, 1: poor). For each patient, we determined that a single beat acquisition was feasible for diagnosis (HCR group) when the number of segments graded score 1 in the HCR image was the same or less than that in the MCR image. Otherwise, we included the patients in the MCR group. HCR group and MCR group included 38 and 36 patients, respectively. Regression analysis showed that body height >1.66 m (odds ratio (OR), 5.74; CI 1.59–25.6; p < 0.007), T₂₃₀ >16 s (OR 3.11; CI 1.07–9.58; p = 0.04), and heart rate ≤72 bpm (OR 3.18; CI 1.11–9.49; p = 0.03) were related with the HCR group. When all three criteria were fulfilled, the calculated probability that MCR would improve image quality was only 7 %. When the heart rate is ≤72 bpm, single heart beat acquisition is feasible for patients with body height >1.66 m and T₂₃₀ > 16 s in coronary CTA using 320-row CT.     

Assessment of atherosclerotic plaques in a rabbit model by delayed-phase contrast-enhanced CT angiography: comparison with histopathology

The aim of this study was to compare delayed-phase computed tomography angiography (CTA) attenuation values with histopathology, in ability to differentiate between fibrous and lipid-rich plaques in an experimental rabbit model. Twelve atherosclerotic rabbits underwent CTA of the abdominal aorta. The scan protocol included early-phase scans (EP), delayed scans at 90 s after contrast injection (DP_90s), delayed scans at 10 min after contrast injection (DP_10min), and delayed scan with saline infusion (DP_Saline). Plaque composition was analyzed by histopathology (% of lipid-rich, fibrous and macrophage areas) and CT attenuation values in Hounsfield units. Using histopathology as the reference standard (n = 119), the overall sensitivity, specificity and accuracy of 64-slice CTA for the detection of plaques was 59, 100 and 79% for the EP scans; 88, 100 and 94% for the DP_90s scans; 81, 100 and 90% for the DP_10min scans; and 53, 100 and 76% for the DP_Saline scans. CT density measurements showed a substantial overlap between fibrous and lipid-rich plaques, and poor correlations with the percentage of macrophage areas in both fibrous and lipid-rich plaques (r = 0.408, and r = 0.333). In delayed-phase 64-slice CTA, DP_90s images have the best diagnostic performance for the detection of aortic plaques.     

人脂肪组织源性干细胞分化为神经元样细胞的能力及可塑性

目的:脂肪组织源性干细胞分化为神经元样细胞并表达神经元信号已有报道.实验拟观察人脂肪组织源性干细胞定向诱导分化为神经元样细胞的可能性.方法:实验于2003-09/2005-06在沈阳脑科医院试验中心完成.腹部脂肪由沈阳市第一医院普外科提供,患者对实验知情同意,并经医院伦理委员会批准.提取人脂肪组织分离、原代培养、扩增脂肪组织源性干细胞,以免疫荧光化学染色方法鉴定细胞CD44,CD114,CD34的表达.取第二、三代细胞以PBS缓冲液冲洗后,用含有丁酸酯羟基茴香醚、KCL、丙戊酸、地塞米松、胰岛素的培养液诱导向神经细胞分化,采用免疫荧光化学染色方法鉴定神经元特异性烯醇化酶.结果:原代培养的脂肪组织源性干细胞为梭形散在细胞,培养至7 d左右细胞接近融合.荧光倒置显微镜下观察经免疫荧光染色,96.7%细胞呈CD44阳性, CD114抗体、CD34抗体呈阴性.神经元特异性烯醇化酶免疫荧光鉴定可见诱导后细胞出现类似轴突和树突样结构,有类神经元间网络形成,表达神经元特异性标志物神经元特异性烯醇化酶.结论:人脂肪组织源性干细胞可在体外扩增,在一定培养条件下,有分化为神经元样细胞的能力.     

Evaluations in mental health services: some methodological considerations

Most health organizations evaluate policies and programmes periodically. Mental health services, without exception, also need to examine their established practices with particular concern about their propriety and effectiveness. As mental health services are coming under increasing pressure to function as self-evaluating organizations that carefully link planning, service delivery and assessment, choices must be made regarding which evaluative strategies are most relevant to the development of mental health services. This paper examines some of the methodological issues in the outcome evaluations in mental health services     

Language barriers and qualitative nursing research: methodological considerations

Aim:  This review of the literature synthesizes methodological recommendations for the use of translators and interpreters in cross-language qualitative research.
Background:  Cross-language qualitative research involves the use of interpreters and translators to mediate a language barrier between researchers and participants. Qualitative nurse researchers successfully address language barriers between themselves and their participants when they systematically plan for how they will use interpreters and translators throughout the research process. Experienced qualitative researchers recognize that translators can generate qualitative data through translation processes and by participating in data analysis. Failure to address language barriers and the methodological challenges they present threatens the credibility, transferability, dependability and confirmability of cross-language qualitative nursing research. Through a synthesis of the cross-language qualitative methods literature, this article reviews the basics of language competence, translator and interpreter qualifications, and roles for each kind of qualitative research approach. Methodological and ethical considerations are also provided.
Conclusion:  By systematically addressing the methodological challenges cross-language research presents, nurse researchers can produce better evidence for nursing practice and policy making when working across different language groups. Findings from qualitative studies will also accurately represent the experiences of the participants without concern that the meaning was lost in translation.     

Demonstrating utility of pharmacogenetics in pediatric populations: methodological considerations

Interpretable and meaningful pharmacogenetic data are dependent on accurate characterization of phenotypes. High-quality reports are critical, and important clinical data must not be omitted. Adequate funding to fully support dedicated program personnel is essential to meet this requirement because an "employee-driven" network that funds its surveillance clinicians is likely to be more effective than a voluntary surveillance model in capturing both adequate numbers of cases and well-characterized clinical data for rigorous phenotyping.     

18^F-FDG PET/CT显像中的棕色脂肪组织摄取

近年来,国内外曾报道在^18F-脱氧葡萄糖（FDG）PET/CT全身显像中,一些位于颈背部、肩胛区、纵隔、肋椎关节旁、肾周等区域的生理性显影是相应区域的棕色脂肪组织（Brown adipose tissue,BAT）摄取了^18F-FDG所致。本文就^18F-FDGPET／CT显像中BAT摄取^18F-FDG的现象做一综述。     

Innovation in nursing management: professional, management and methodological considerations

There are many changes occurring in the National Health Service (NHS) at this time, not just to economic and funding policies, but also at the very heart of nursing care delivery. The introduction of 'managerialism' into the senior clinical grades of nursing, midwifery and other professional staff has characterized the past few years. Against this backdrop is the increasing belief that NHS organizations must find improved ways of delivering patient care and other services. This has inexorably led to the consideration of diffusing innovation into practice as a way to improve performance and competitiveness. While there have been a number of clinical attempts at understanding this process, there has been very little written about innovation from the perspective of the nurse (or midwifery) clinical manager. This paper discusses some of the issues surrounding management innovation including the planning of interventions aimed at introducing innovation, and some of the methodological difficulties of studying complex organizations. The wider issues of innovation, nursing management and professional staff are also discussed.