Comparison of High-field and Low-field Magnetic Resonance Imaging of Stifle Joint Disorders in Dogs

The most common cause of hindlimb lameness in dogs is cranial cruciate ligament rupture. In 48-77.3% of the population this trauma leads to secondary damage of the meniscus. Depending on the magnetic strength of the used device, different diagnostic accuracy can be achieved. The examination sensitivity of magnetic resonance imaging is affected by many factors which are independent of diagnostic strength, such as correct positioning of the patient, size of the stifle joint examined, or selection of the right protocol of sequences. Sensitivity of meniscus damage detection was 100% and 90%, respectively, in high- and low-field magnetic resonance. The best results were reported during examination of the stifle in dogs above 10 kg b.w. at a flexion angle of 145°, and in sagittal and dorsal planes. Regardless of the magnetic strength applied, imaging of the whole cranial cruciate ligament is difficult. Moreover, MRI allows the detection of the first signs of osteoarthritis, which were observed 4 and 6 weeks after rupture of the cranial cruciate ligament using high and low-field MRI. This also applies to lesions in the subchondral bone or a bone marrow which occurred in association with insufficiency of the stifle joint, and were mainly localized in the epiphysis of the femur and tibia. The present article provides a comparison of different examination protocols and images of damaged stifle structures, such as menisci, ligaments and bones of the stifle joint visualized with low-field and high-field magnetic resonance. Magnetic resonance arthrography is also discussed.

Attentional bias to threat in social phobia: facilitated processing of threat or difficulty disengaging attention from threat?

There is a growing body of research pointing to the possibility that anxious individuals may have difficulty disengaging their attention from threat-relevant information when this information is task irrelevant (e.g., Amir, N., & Elias, J. (2002). Allocation of attention to threat in social phobia: difficulty in disengaging from task irrelevant cues, Manuscript under review; The Quarterly J. Expo. Psycho. 54A (2001) 665). In the current paper, we report a direct test of this hypothesis in individuals with social phobia. Participants performed a variation of the Posner paradigm (Quart. J. Exp. Psycho. 32 (1980) 3). Social threat, neutral, or positive words cued one of two locations on the computer screen. After the cue disappeared, participants had to detect a probe ("(*)") that appeared in one of the two locations. On some trials the cue was valid (i.e., the probe appeared in the same location as the cue). On other trials the cue was invalid (the probe appeared in a different location than the cue). Yet, on other trials, no cue was presented. All participants were slower in detecting probes following invalid cues than probes following valid cues. Furthermore, individuals with social phobia showed significantly longer response latencies when detecting invalidly cued targets than did controls, but only when the probe followed a social threat word. These results suggest that individuals with social phobia may have difficulty disengaging their attention from socially threatening material.

Inflated perception of responsibility for harm in obsessive-compulsive disorder

The present study examined the proposition that inflated responsibility is implicated in obsessive compulsive disorder (OCD). Compared to non-anxious control participants (NACs), and an anxious control group with generalized social phobia (GSPs), we predicted that individuals with OCD (OCs) would exhibit a greater urge to rectify situations involving potential risk, would report more distress upon leaving such situations unrectified, and would feel more personal responsibility if the unrectified situations resulted in harm. Fifteen OCs, 15 NACs, and 15 GSPs completed the Obsessive Compulsive Responsibility Scale (OCRS), which included low-risk, OC-relevant, and high-risk situations. Compared to NACs and GSPs, OCs reported more urges, distress, and responsibility in low-risk and OC-relevant situations; no group differences were detected on high-risk situations. GSPs and NACs differed only in their responsibility in OC-relevant situations, with GSPs reporting higher responsibility than controls. Our results suggest that compared to OCs, NACs, and GSPs can better differentiate between situations that merit concern and ones that do not.