CT Densitometry and Morphology of Radiofrequency-Ablated Stage IA Non–Small Cell Lung Cancer: Results from the American College of Surgeons Oncology Group Z4033 (Alliance) Trial

PurposeTo evaluate tumor and ablation zone morphology and densitometry related to tumor recurrence in participants with Stage IA non–small cell lung cancer undergoing radiofrequency ablation in a prospective, multicenter trial.Materials and MethodsForty-five participants (median 76 years old; 25 women; 20 men) from 16 sites were followed for 2 years (December 2006 to November 2010) with computed tomography (CT) densitometry. Imaging findings before and after ablation were recorded, including maximum CT attenuation (in Hounsfield units) at precontrast and 45-, 90-, 180-, and 300-s postcontrast.ResultsEvery 1-cm increase in the largest axial diameter of the ablation zone at 3-months’ follow-up compared to the index tumor reduced the odds of 2-year recurrence by 52% (P = .02). A 1-cm difference performed the best (sensitivity, 0.56; specificity, 0.93; positive likelihood ratio of 8). CT densitometry precontrast and at 45 seconds showed significantly different enhancement patterns in a comparison among pretreated lung cancer (delta = +61.2 HU), tumor recurrence (delta = +57 HU), and treated tumor/ablation zone (delta [change in attenuation] = +16.9 HU), (P < .0001). Densitometry from 45 to 300 s was also different among pretreated tumor (delta = −6.8 HU), recurrence (delta = −11.2 HU), and treated tumor (delta = +12.1 HU; P = .01). Untreated and residual tumor demonstrated washout, whereas treated tumor demonstrated increased attenuation.ConclusionsAn ablation zone ≥1 cm larger than the initial tumor, based on 3-month follow-up imaging, is recommended to decrease odds of recurrence. CT densitometry can delineate tumor versus treatment zones.     

Neural selectivity,efficiency, and dose equivalence in deep brain stimulation through pulse width tuning and segmented electrodes

BackgroundAchieving deep brain stimulation (DBS) dose equivalence is challenging, especially with pulse width tuning and directional contacts. Further, the precise effects of pulse width tuning are unknown, and recent reports of the effects of pulse width tuning on neural selectivity are at odds with classic biophysical studies.MethodsWe created multicompartment neuron models for two axon diameters and used finite element modeling to determine extracellular influence from standard and segmented electrodes. We analyzed axon activation profiles and calculated volumes of tissue activated.ResultsWe find that long pulse widths focus the stimulation effect on small, nearby fibers, suppressing distant white matter tract activation (responsible for some DBS side effects) and improving battery utilization when equivalent activation is maintained for small axons. Directional leads enable similar benefits to a greater degree. Reexamining previous reports of short pulse stimulation reducing side effects, we explore a possible alternate explanation: non-dose equivalent stimulation may have resulted in reduced spread of neural activation. Finally, using internal capsule avoidance as an example in the context of subthalamic stimulation, we present a patient-specific model to show how long pulse widths could help increase the biophysical therapeutic window.DiscussionWe find agreement with classic studies and predict that long pulse widths may focus the stimulation effect on small, nearby fibers and improve power consumption. While future pre-clinical and clinical work is necessary regarding pulse width tuning, it is clear that future studies must ensure dose equivalence, noting that energy- and charge-equivalent amplitudes do not result in equivalent spread of neural activation when changing pulse width.     

The challenges in scoring hypopneas in children: is pulse wave amplitude drop the answer?

BackgroundIdentifying electroencephalogram (EEG) cortical arousals are crucial in scoring hypopneas and respiratory efforts related arousals (RERAs) during a polysomnogram. As children have high arousal threshold, many of the flow limited breaths or hypopneas may not be associated with visual EEG arousals, hence this may lead to potential underestimation of the degree of sleep disordered breathing. Pulse wave amplitude (PWA) is a signal obtained from finger photoplethysmography which correlates directly to finger blood flow. The drop in PWA has been shown to be a sensitive marker for subcortical/autonomic and cortical arousals. Our aim was to use the drop in PWA as a surrogate for arousals to guide scoring of respiratory events in pediatric patients.MethodsTen polysomnograms for patients between the ages of 5–15 years who had obstructive apnea-hypopnea indices between 1 and 5 events/hour were identified. Patients with syndromes were excluded. A drop in PWA signal of at least 30% that lasted for 3 s was needed to identify subcortical/autonomic arousals. Arousals were rescored based on this criteria and subsequently respiratory events were rescored. Paired t-tests were employed to compare PSG indices scored with or without PWA incorporation.ResultsThe sample of 10 children included 2 females, and the average age was 9.8 ± 3.1 years. Overall, polysomnography revealed an average total sleep time of 464.1 ± 25 min, sleep efficiency of 92% +/−4.2, sleep latency of 19.6 ± 17.0 min, rapid eye movement (REM) latency 143 ± 66 min, N1 3.9% +/−2.0, N2 50.3% +/−12.0, N3 28.2% +/−9.1, REM 16.7% +/−4.0, and wakefulness after sleep onset (WASO) 18.1 ± 7.5 min. Including arousals from PWA changes, respiratory indices significantly increased including total AHI (2.3 ± 0.7 vs 5.7 ± 2.1, p < 0.001), obstructive AHI (1.45 ± 0.7 vs 4.8 ± 1.8, p < 0.001), and RDI (2.36 ± 0.7 vs 7.6 ± 2.0, p < 0.001). Likewise, total arousal index was significantly higher (8.7 ± 2.3 vs 29.4 ± 6.5, p < 0.001).ConclusionsThe drop in pulse wave amplitude signal is a useful marker to guide scoring arousals that are not otherwise easily identified in pediatric polysomnography and subsequently helped in scoring respiratory events that otherwise would not be scored. Further studies are needed to delineate if such methodology would affect clinical outcome.     

Development and function of tissue resident macrophages in mice

Macrophages are important for tissue development, homeostasis as well as immune response upon injury or infection. For a long time they were only seen as one uniform group of phagocytes with a common origin and similar functions. However, this view has been challenged in the last decade and revealed a complex diversity of tissue resident macrophages. Here, we want to present the current view on macrophage development and tissue specification and we will discuss differences as well as common patterns between heterogeneous macrophage subpopulations.     

老年高血压患者脉压与急性心肌梗塞的关系

目的探讨老年原发性高血压（ET）患者脉压与急性心肌梗塞（AMI）的关系。方法观测45例老年高血压病合并急性心肌梗塞患者的收缩压（SBP）、舒张压（DBP）及脉压（PP），以31例老年单纯高血压患者（冠脉造影排除冠心病）作对照组，进行比较。结果并发急性心肌梗塞组，其脉压较单纯高血压组明显增高。结论脉压与老年人急性心肌梗塞密切相关，对老年人高血压的治疗更要注重控制脉压。     

多普勒组织成像技术在评价高血压左室舒张功能中的应用

目的 :应用多普勒组织成像 (DTI)技术检测二尖瓣环舒张期运动速度来评介原发性高血压左室舒张功能 ,探讨DTI的临床应用价值。方法 :2 0例原发性高血压和 2 0例年龄相似的健康者 ,应用DTI技术对二尖瓣环室间隔侧的运动速度进行测定 ,并与常规二尖瓣血流脉冲多普勒 (PW)检测结果对照分析。结果 :PW高血压组与对照组比较 ,峰值速度E、A及E/A明显低于对照组 ,差异显著 (P <0 0 1) ;DTI高血压组与对照组比较 ,峰值速度Ea、Aa及Ea/Aa明显低于对照组 ,差异非常显著 (P <0 0 0 1)。PW、DTI两组相同部位间比较 ,高血压组低于对照组。结论 :DTI技术评价高血压左室舒张功能比常规脉冲多普勒二尖瓣血流参数更敏感     

A comparison of conventional and fast spin-echo sequences for the measurement of lesion load in multiple sclerosis using a semi-automated contour technique

Changes on serial assessments of brain MRI lesion load are used for monitoring therapeutic efficacy in patients with multiple sclerosis (MS). We assessed the accuracy and reliability of conventional spin-echo (CSE) and fast spin-echo (FSE) sequences for measurement of lesion volume using a semiautomated contour technique. Cranial CSE and FSE examinations of 18 patients with secondary progressive MS were studied. The mean lesion load was slightly higher with the CSE sequence (p = 0.002). Intraobserver variability was significantly higher for FSE than for CSE, according to both the coefficient of variation between two measurements (mean 2.48 % and 1.35 % respectively, p < 0.05) and back-transformed 95 % limits of agreement (1.005–1.060 for FSE; 0.988–1.019 for CSE). Although FSE sequences are quicker and the total lesion volume measurements are similar to those obtained with CSE, the poorer reproducibility raises doubts about the use of FSE to replace CSE in clinical trials. Received: 26 March 1996 Accepted: 4 April 1996     

Choice of open or percutaneous procedures in the surgical treatment of trigeminal neuralgia

The aim of this study was to define criteria for the selection of patients for percutaneous or open operations for the cure of drug-resistant trigeminal neuralgia (TN). Trigeminal percutaneous radiofrequency thermorhizotomy (TPRT) has an established place because of its safety in elderly patients, while microvascular decompression (MVD) has appeal in younger patients beause of its non-destructive nature and because it attacks what is believed to be the primary etiology of tic douloureux. Nevertheless, MVD is a successful operation only when true neurovascular conflict (NVC) is ascertained, rather than a simple arterial loop and neurovascular contract. Probably, many immediate failures and early relapses are the consequence of the inadequate patient selection for MVD on the presumption that this operation is in any case the ideal cure. The inadequate selection can be explained by the difficult preoperative diagnosis of NVC in the past. Indeed, angiography and computed tomography showed the neurovascular contact but not the size of compression. Fortunately, today magnetic resonance imaging is a reliable instrument to ascertain NVC. So, the diatribe between the supporters of percutaneous techniques and MVD can be concluded with the following: (1) percutaenous techniques are indicated for patients without demonstrated NVC (including patients with TN in multiple sclerosis) and in those with NVC if MVD is contraindicated by ill-health or refused by the informed patient; and (2) MVD is incated for patients with ascertained NVC who are in good health and who, informed of the surgical risk, favor this operation desiring no sensory deficit. Received: 23 June 2001 / Accepted in revised form: 24 August 2001