Exposure to the elevated plus-maze induces behavioural and physiological effects in rodents consistent with fear/anxiety. Maze-naive animals display high levels of risk assessment towards the open arms, and explore these areas less extensively than other parts of the maze while, immediately following the test, pain latencies, skin conductance levels, and plasma corticosterone titres (CORT) are significantly elevated. Although previous research has suggested a link between the plasma CORT response and open-arm exploration, significant elevations in CORT have also been found with restricted exposure to the closed arms. The present study employed ethological measures in an attempt to further characterise the relationship between behavioural and CORT responses to this widely used animal model of anxiety. Our results confirm that, relative to home-cage controls, 5-min exposure to the plus-maze significantly increases plasma CORT levels in test-naive male Wistar rats and male Swiss-Webster mice. Furthermore, in both species, the CORT response was found to be highly correlated with measures of risk assessment (mice: rs = +0.87; rats: rs = +0.58), but not with measures of open-arm activity (entries, time), general locomotor activity, rearing, or head dipping. Findings are discussed in relation to the functional significance of risk assessment in potentially dangerous situations and the potential involvement of glucocorticoids in this process. All rights reserved.

Animals↗

PubMedDate not supplied

Juxtaacetabular ganglionic (or synovial) cysts: CT and MR features.

Radiographic findings include supraacetabular bone erosions, subchondral acetabular cysts, soft tissue masses with or without radiolucent inclusions representing nitrogen gas, joint space narrowing, and abnormal hip configuration. Associated tears of the acetabular labrum were confirmed by arthrography in two patients. Computed tomography and magnetic resonance imaging afforded improved delineation of soft tissue ganglia and their relationship to the acetabular bone, labrum, and hip joint. We report our experience with seven patients in whom various imaging examinations clearly documented the presence of soft tissue cystic lesions adjacent to the acetabulum; in six of the seven patients, significant clinical manifestations were evident in the affected hip. Such cysts, whether designated synovial or ganglionic in type, appear to be a frequently overlooked yet important cause of hip symptomatology.

Acetabulum↗

PubMedDate not supplied

Bone marrow edema of the hip: MR findings after core decompression.

Magnetic resonance imaging is an extremely sensitive technique for evaluation of bone marrow changes at an early stage of avascular necrosis (AVN) of the hip. We therefore examined 11 painful hips whose clinical symptoms led us to suspect idiopathic AVN. The radiographs of all of these either were normal or demonstrated a minimal decrease in radiodensity. Magnetic resonance demonstrated diffuse signal loss of the bone marrow at short TR/TE images of the femoral head in all hips, with various extensions in the head, neck, and intertrochanteric area. These regions turned iso- to hyperintense on long TR/TE images compatible with bone marrow edema (BME). Focal abnormalities characteristic for AVN were not seen in any of the cases. Radionuclide studies performed in six cases were positive. All patients underwent core decompression treatment. Hydrostatic bone marrow pressure measurement and intraosseous venography were positive in five cases when measured. Histology available in eight cases confirmed the presence of BME. Furthermore, the bone changes corresponded to those of early AVN. Follow-up examinations after core decompression with MR showed normal signal intensity in all cases. Magnetic resonance represents a viable diagnostic tool for BME and can monitor the therapeutic success of core decompression. Whether BME of the femoral head constitutes a distinct transient syndrome or represents an early form of AVN is controversial at present. Our findings support those who believe that BME may represent an initial stage of idiopathic AVN.

Adult↗

PubMedDate not supplied

MRI of the sinus tarsi in acute ankle sprain injuries.

PURPOSE: Our goal was to evaluate the visibility and incidence of traumatic abnormalities of the sinus tarsi in patients with acute ankle sprain injuries and compare these findings with the extent of lateral ankle ligament injuries on MRI. METHOD: Sixty athletically active patients (aged 18-45 years) with recent inversion trauma (< or = 7 days) underwent MRI. Replacement of fat tissue in the sinus tarsi was recorded. Inter/intraobserver agreement was calculated (kappa-statistics). Injuries of the three lateral ligaments, evaluated by MRI, were graded according to partial (1 point) or complete (2 points) tears for each of three lateral ligaments (together 0-6 points) and were compared with sinus tarsi abnormalities. RESULTS: In 26 patients (43%), replacement of sinus tarsi fat tissue was depicted by MRI. Inter/intraobserver agreement for MR changes of the sinus tarsi was good to moderate (kappa = 0.675/0.584). Grade of lateral ankle ligament injury showed a statistically significant difference (p = 0.033) between the two sinus tarsi groups (normal/abnormal). CONCLUSION: Acute ankle sprain injuries, evaluated by MRI, are associated with acute abnormalities of the sinus tarsi in 43% of patients and correlate with the extent of lateral ankle ligament tears.

Acute Disease↗

PubMedDate not supplied

MRI versus lateral stress radiography in acute lateral ankle ligament injuries.

PURPOSE: Our goal was to compare the abilities of MRI and stress radiography to detect the extent of recent lateral ankle ligament inversion injuries. METHOD: In this prospective study, 60 athletically active patients (aged 18-45 years) with recent inversion trauma (< or = 7 days) underwent stress radiography and MRI. In 15 patients, the MR findings were reviewed at surgery. Patients were divided into three groups according to severity of ligament injury on MRI (no, one, or two to three ligament tears). Based on bilateral stress radiography, patients were classified into three groups according to the differential degree of talar tilt (< or = 5, 6-14, or > or = 15 degrees) and compared with patients from the MR groups. RESULTS: Surgery showed MRI to have 74% sensitivity and 100% specificity in the evaluation of complete lateral ankle ligament tears. Agreement between MR and stress radiography groups for the severity of recent lateral ankle ligament tears was poor (kappa = 0.030). CONCLUSION: MRI should be performed in young, athletically active patients if surgical intervention is contemplated, especially at 6-14 degrees talar tilt on stress radiography, since stress radiography tends to over- and underestimate the severity of lateral ligament trauma.

Acute Disease↗