Optic nerve injury demonstrated by MRI with STIR sequences

We studied nine patients with optic nerve injury associated with closed head trauma by magnetic resonance imaging (MRI) with short inversion time inversion recovery (STIR) sequences on 11 occasions from 4 days to 14 years after the injury: three studies were within 17 days and eight over 4 months to 14 years. MRI revealed abnormal high signal in 10 of the 11 injured nerves. MRI 4 days after the injury showed no abnormality.     

光照黄斑部试验的临床研究─—眼底病患者MPT的改变及其机理的探讨

７９只眼底病患眼的光照黄斑部试验（ＭＰＴ）结果显示：中心性浆液性脉络膜视网膜病变、老年性黄斑变性渗出型和Ｒｉｅｇｅｒ型中心性渗出性脉络膜视网膜病变患眼的光照黄斑恢复时间显著延长，其它黄斑部病变患眼也有不同程度的延长。本文结合眼底荧光血管造影和黄斑视野域值试验对光照黄斑部试验的机理进行了探讨。     

Treatment time analysis for extensive amalgam restorations

The treatment times for the fabrication of Extensive Amalgam Restorations (EAR) as recorded in a longitudinal clinical trial at the Dental School in Nijmegen were analyzed. 269 EAR's with different retention methods were made on molars by three operators. A mean total treatment time of 60 min was found. The factor operator had a significant influence on all treatment phases resulting in a 26% difference in total treatment time between operators. Also significant influences were found in some treatment phases for the factor retention, side location of the tooth and extension of the restoration. The results of this study with regard to treatment times must be considered from the perspective of the quality of the care provided.     

Ten-year stability of cardiovascular responses to laboratory stressors

In this study we examined test-retest stability of cardiovascular stress responses over a decade of the life span. Participants were 55 male college undergraduates. 19 years of age at initial testing, and 29 years of age at follow-up testing Stressors were a foot cold pressor and an aversive reaction time task. Cardiovascular measures included systolic and diastolic blood pressure, heart rate, and preejection period. For cold pressor, the magnitude and pattern of cardiovascular responses remained unchanged at the 10-year follow-up. For the reaction time task, the characteristic cardiovascular response patterns was preserved but with significant attenuation of magnitude. The present findings are consistent with previous observations of temporal stability but over a substantially longer test-retest interval. The long-term stability of stress responses is discussed in the context of stress test methodology, behavioral response demands, and maturation of the physiological systems involved in cardiovascular response expression.     

Restricted field of view magnetic resonance imaging of a dynamic time series.

A restricted field of view (rFOV) approach for imaging a dynamic time series of volumes of limited spatial extent within a larger subject is described. The shorter readout with rFOV-MRI can be exploited to either limit image artifacts or increase spatial resolution. To accomplish rFOV imaging of a multislice volume for a dynamic series, an outer volume suppression (OVS) preparation that saturates signal external to a cylinder through the subject is followed by slice-selective excitation and a spiral readout. The pass- and stopband efficiencies of the OVS in an agar gel phantom were 97% (+/-1.5%) and 3% (+/-1%), respectively. Profiles of the temporal signal-to-noise ratio (SNR) were measured in a phantom and an adult brain. The rFOV sequence reduced distortions from off-resonance signal and T2*-induced blurring compared to a conventional sequence. Sequence utility is demonstrated for high-resolution rFOV functional MRI (fMRI) in the visual cortex. The rFOV sequence may prove to be useful for other multislice dynamic and high-resolution imaging applications.     

青年男性MMPI-215F量表应答时间效应分析

目的分析青年男性心理测评中F量表条目应答时间,研究其相关影响因素和变化规律,并对该测评计算机化过程中应答时间的设定提供一定的参考.方法使用MMPI-215对全国18个省市的青年男性进行测试,利用计算机对时间记录,汇总分析.结果青年男性在F量表各条目平均应答时间（以下简称F均时）为4.57s;低于总测试的各条目平均应答时间（6.34 s）（P＜0.01）;F均时与F分数、应答前后不一致的条目数以及漏答条目数有显著相关;F均时受文化程度、年龄、城乡结构多种因素影响;每个条目的应答时间主要取决于条目汉字的个数.结论 F均时在测评中表现出一定的变化规律,可以结合临床进一步深入研究,使其成为评价青年男性性格特征的客观性指标之一.     

Monocular contribution to the peak time of the binocular pattern visual evoked potential

The contribution of each monocular pathway to the timing of the binocular pattern visual evoked potential was assessed in situations where a significant interocular timing discrepancy was observed. Monocular and binocular pattern visual evoked potentials to 0.5° checks were recorded from normal subjects, normal subjects in whom one eye was blurred, patients with monocular amblyopia, and patients with resolved unilateral optic neuritis. Normal subjects showed facilitation, while suppression was evidenced in subjects with monocular blurring. In patients with amblyopia, the affected pathway had no effect on binocular pattern visual evoked potential latency, suggesting that the amblyopic eye was suppressed. In contrast, all patients with optic neuritis showed binocular averaging. Our results show that different forms of binocular interaction are evidenced in normal subjects, in amblyopia and in optic neuritis, and suggest that a comparative analysis of monocular and binocular pattern visual evoked potential peak times brings valuable information to the clinical evaluation that could be used to distinguish disease processes further.Abbreviation BPVEP binocular pattern visual evoked potential     

Measurement of arterial input functions for dynamic susceptibility contrast magnetic resonance imaging using echoplanar images: comparison of physical simulations with in vivo results.

Measurement of the arterial input bolus shape is essential to the quantification of mean transit time and blood flow with dynamic susceptibility contrast (DSC) MRI. Input functions derived from the echoplanar signal intensity within or near arteries are highly nonlinear, yet such input functions are widely used. We employed a physical model for the echoplanar signal intensity from an artery as a function of contrast agent concentration, artery size, and angle to the magnetic field to test approaches for the measurement of the arterial input function. The simulated results confirmed the strong nonlinearity of signal in the neighborhood of vessels. Of the input function measurement methods considered, the simulations suggested that measurement of signal near but not within a large vessel is most accurate, but mean transit times (MTT) calculated with these input functions are highly sensitive to peak bolus concentration. Input functions determined from voxels demonstrating the shortest first moment overestimated the MTT but the measured MTTs were more robust to changes in peak concentration. Characteristics of the measured in vivo input functions were consistent with the simulations. Our results emphasize the important contribution of input function errors to the uncertainty in MTT and blood flow imaging with DSC MRI.     

Magnetic resonance relaxation times of normal tissue in the course of chemotherapy: a study in patients with bone sarcoma

To study the effect of chemotherapy on normal fat, skeletal muscle, and bone marrow, T1 and T2 relaxation times were measured in 15 patients with bone sarcoma before and after each cycle of preoperative chemotherapy. A section plane containing the tumor and if possible the nonaffected extremity was imaged with combined multiecho spin echo and inversion recovery pulse sequences. T1 and T2 relaxation times were calculated in the normal-appearing tissues. Although some variation was found in the values in the individual patient and between patients, no systematic changes of relaxation times of fat, muscle, or bone marrow occurred in the course of treatment. We conclude that the chemotherapy used in bone sarcoma has no effect on relaxation times of normal fat, muscle, and bone marrow, and that therefore these tissues may serve as a reference for the signal intensity of tumor.