Spinal Bone Bruise: Can Computed Tomography (CT) Enable Accurate Diagnosis?

RATIONALE AND OBJECTIVES

The study aimed to evaluate the usefulness of dual-energy computed tomography (DECT) before and after calcium subtraction in the diagnosis of spinal bone bruise.

MATERIALS AND METHODS

Among the patients who visited our emergency department between January 2013 and July 2014 who underwent both spinal DECT and magnetic resonance imaging, 38 patients (men:women = 25:13; mean age: 55.6 years, range: 28-82) were included. The patients were divided into two groups, those with and without acute spinal compression fracture, based on magnetic resonance imaging findings. In the fracture group (n = 22), the ratio of Hounsfield unit (HU) values was calculated between the fracture level and the next normal inferior vertebra in the DECT before and after calcium subtraction. In the non-fracture group (n = 16), the ratios of HU values were calculated between two normal adjacent vertebrae. The mean HU ratios were compared between the two groups.

RESULTS

The mean HU ratio was higher in the fracture group (calcium subtraction: before: 1.57 and 1.59; after: 1.74 and 1.76) than the non-fracture group (before: 1.07 and 1.08; after: 1.07 and 1.07) (P < 0.001). The mean HU ratio between before and after calcium subtraction images was different only in the fracture group (P < 0.05). There was no significant difference in the area under the curve, sensitivity, specificity, positive and negative predictive values, and accuracy (before: 0.846, 87.5%, 81.2%, 87.5%, 81.2%, 85%; after: 0.865, 91.7%, 81.2%, 88%, 86.7%, 87.5% in high energy) between the images before and after calcium subtraction.

CONCLUSION

The HU ratio between the fractured and next normal vertebra was diagnostic for spinal bone bruise on DECT images both before and after calcium subtraction.

[Comparing the two neurobehavioral toxicological methods on the toxic effect of methyl mercury]

To compare the two experimental methods for testing neurobehavioral toxicological effects, methyl mercury chloride at the dosage of 0.00, 0.01, 0.05 and 2.00 mg/(kg.d) was force-fed to pregnant Wistar rats during the 6-9th day of conception. The offspring of the 4 groups were randomly selected for Y maze or operant behavior test at the age of 7 or 10 weeks, respectively. The reinforcements of the performance were electric shock for Y maze and food pellets for operant behavioral test. The results showed that no sex-dependent effects were observed both in maze and operant behavior tests. The performances of offspring in 3 exposure groups were worse than that of control group both in Y maze and operant behavior tests(P < 0.05). It was demonstrated that a clear dose-effect relationship in maze test on error time(rs = 0.257, P < 0.05), arrival time(rs = 0.216, P < 0.01); in operant behavior test on differential reinforcement of high rate (rs = -0.7273, P < 0.01), but not on differential reinforcement of low rate(rs = -0.2238, P > 0.05). It is concluded that prenatal methyl mercury exposure caused some negative effects on the development of nervous system. But the negative reinforcement by human operation in Y maze test could affect the results. The positive reinforcement and automatic monitoring in operant behavioral test gave more reliable results.

Spatial bias: attentional and intentional influence in normal subjects

Normal subjects often demonstrate a spatial bias on line bisection (LB) and cancellation (CA) tasks. We wanted to learn if horizontal spatial bias found in normal subjects may be dissociable into sensory-attentional (ATT) and motor-intentional (INT) subgroups similar to those described in brain-injured patients with spatial neglect. We studied the influence of ATT and INT factors on the spatial bias observed in normal subjects using a new technique that uncouples the direction of action from the direction of attention. This technique also allowed us to test both LB and CA tasks on the same individuals. Our results show that ATT bias significantly influenced performance on an LB task, whereas performance on a CA task was influenced by biases in both the ATT and INT systems. In addition, the overall bias on these two tasks reflects an interaction between the biases induced by the ATT and INT systems that may be in the same or different directions.