Distribution of normal and abnormal fluid collections in the glenohumeral joint: Implications for MR arthrography

Although magnetic resonance (MR) images of the glenohumeral joint frequently demonstrate intraarticular fluid, no specific criteria have, to the authors' knowledge, been published that allow accurate assessment of the amount of fluid present. Also, despite the increasing use of MR arthrography of the shoulder, the optimal amount of intra-articular fluid that should be used with this technique has not been determined. The authors progressively distended the glenohumeral joint in six cadaveric shoulder specimens with a dilute gadopentetate dimeglumine solution and obtained MR images after injection of 2, 5, 10, 15, and 20 mL of the solution. The pattern of fluid distribution was evaluated, and these results were then used to estimate the amount of fluid that was present in the glenohumeral joint on MR images of 20 shoulders obtained in 12 asymptomatic volunteers. In 14 of these shoulders, intraarticular fluid was present; however, in none was more than 2 mL evident. Results of the cadaveric study also indicated that 15 mL of intraarticular fluid appears to be the optimal amount for MR arthrography.     

Pathological laughter and crying in patients with multiple system atrophy-cerebellar type.

In the cerebellar type of multiple system atrophy (MSA-C), the burden of pathological changes involves the cerebellum and its associated brainstem structures in the basis pontis and the inferior olivary nucleus, and as a result, the clinical phenotype is dominated early on by the cerebellar dysfunction. We report our clinical and post mortem findings in a patient with MSA-C who exhibited pathological laughter in the absence of any congruent changes of mood. A review of the clinical notes of 27 other patients with MSA-C revealed a problem with pathological laughter, or crying, or both in 9 more patients. Our finding of about 36% occurrence suggests that the problem of dysregulation of emotional expression is more prevalent in MSA-C than the paucity of reports in the literature suggests. Our findings are consistent with the view that the cerebellum and its interconnected structures may be involved in the regulation of emotional expression.     

Tissue characterization of symptomatic and asymptomatic disc herniations by quantitative magnetic resonance imaging

The purpose of this investigation was to determine differences in tissue composition of symptomatic and asymptomatic disc herniations as reflected in T₁ and T₂ relaxation times (quantitative magnetic resonance investigation of the lumber spine. The longitudinal and transverse magnetic rlaxation times (T₁ and T₂, respectively) were calculated from a set of 20 images obtained with five single-slice/multi-echo sequences at different repetition time values on a commercial whole-body system (1.5 T). Twenty-two symptomatic and asymptomatic disc herniations could be matched according to age, gender, disc level, and the extent of herniation (protrusion or extrusion) and were compared with regard to T₁ and T₂ relaxation times. Symptomatic disc herniations exhibited significantly (p_T1 < 0.04 and p_T2 < 0.003) shorter T₁(ΔT₁:–182.1 milliseconds, ?15%) and T₂(ΔT₂: ?11.0 milliseconds, ?21%) relaxation times than matched asymptomatic herniations. Symptomatic disc herniations also exhibited more advanced disc degeneration as graded by Pearce's criteria (p < 0.01). These results suggest that symptomatic and morphologically matched asymptomatic disc herniations differ with regard to disc matrix composition.     

Method for the quantitative assessment of contrast agent uptake in dynamic contrast-enhanced MRI

In previous papers relative signal intensity increase was used as a quantitative assessment parameter for contrast uptake in contrastenhanced MRI. However, relative signal intensity increase does not only reflect contrast uptake but depends also on tissue parameters (native T₁ relaxation time) and sequence parameters (repetition time and flip angle); thus, the contrast uptake cannot be assessed accurately using relative signal intensity increase. Based on an analysis of the contrast behavior of spoiled gradient echo sequences, a method is described in this paper that overcomes the limitations of relative signal intensity increase measurement. A parameter, called “enhancement factor” (EF) is introduced that approximates differential T₁ relaxation rate. The enhancement factor scales linearly with contrast uptake and is independent of tissue and sequence parameters. The additional measurement time involved in determining the enhancement factor is less than 1 min and computation is straightforward. The practicality of the new method was confirmed by phantom measurements using T₁-weighted and proton density-weighted spoiled gradient echo sequences (FLASH-2D). Enhancing tissues were simulated by water phantoms doped with increasing concentrations of Gd-DTPA.     

Antihypertensive mechanisms of chronic captopril or N-acetylcysteine treatment in L-NAME hypertensive rats.

Hypertension due to chronic inhibition of NO synthase (NOS) by Nomega-nitro-L-arginine methyl ester (L-NAME) administration is characterized by both impaired NO-dependent vasodilation and enhanced sympathetic vasoconstriction. The aim of our study was to evaluate changes in the participation of major vasoactive systems in L-NAME-treated rats which were subjected to simultaneous antihypertensive (captopril) or antioxidant (N-acetylcysteine, NAC) treatment. Three-month-old Wistar males treated with L-NAME (60 mg/kg/day) for 5 weeks were compared to rats in which L-NAME treatment was combined with simultaneous chronic administration of captopril or NAC. Basal blood pressure (BP) and its acute responses to consecutive i.v. injections of captopril (10 mg/kg), pentolinium (5 mg/kg), L-NAME (30 mg/kg), tetraethylammonium (TEA, 16 mg/kg) and nitroprusside (NP, 20 microg/kg) were determined in conscious rats at the end of the study. The development of L-NAME hypertension was prevented by captopril treatment, whereas NAC treatment caused only a moderate BP reduction. Captopril treatment normalized the sympathetic BP component and significantly reduced residual BP (measured at full NP-induced vasodilation). In contrast, chronic NAC treatment did not modify the sympathetic BP component or residual BP, but significantly enhanced NO-dependent vasodilation. Neither captopril nor NAC treatment influenced the compensatory increase of TEA-sensitive vasodilation mediated by endothelium-derived hyperpolarizing factor in L-NAME-treated rats. Chronic captopril treatment prevented L-NAME hypertension by lowering of sympathetic tone, whereas chronic NAC treatment attenuated L-NAME hypertension by reduction in the vasodilator deficit due to enhanced NO-dependent vasodilation.     

Differential effect of catechol-O-methyltransferase Val158Met genotype on emotional recognition abilities in healthy men and women.

The catechol-O-methyltransferase (COMT) Val158Met polymorphism modulates executive functions and working memory and recent neuroimaging studies implicate an association with emotional processing. We examined the relationship between the COMT Val158Met polymorphism and facial emotion recognition and differentiation in 100 healthy individuals. Compared to Met homozygosity, Val homozygosity was associated with better and faster recognition of negative facial expressions such as anger and sad. Our study provides evidence for a possible influence of the COMT polymorphism on emotion recognition abilities in healthy subjects. Additional research is needed to further define the neurocognitive phenotypes associated with COMT polymorphisms.     

Verifikation und Anwendungen des voxelbasierten Monte-Carlo-(VMC++-)Elektronen-Dosismoduls von Oncentra™ MasterPlan

PURPOSE, MATERIAL AND METHODS: The dose calculation accuracy of the voxel-based Monte Carlo (VMC++) electron dose module of Oncentra MasterPlan (Nucletron B.V., Veenendaal, The Netherlands) was verified by measurements in homogeneous water phantoms. RESULTS: Measured and calculated dose maxima on the central beam axis (calculations with 10,000-20,000 incident electron histories per cm(2)) agree well using standard applicator configurations as well as individually shaped inserts. Profile scans with higher electron energies (>/= 15 MeV) reveal differences up to 5% especially in the penumbra region. Depth dose curves agree best in the vicinity of maximum depths. In the buildup region energy-dependent differences up to 5% in both directions could be observed. In the decay region of depth dose curves calculated doses were up to 10% higher than measured values. CONCLUSION: Good VMC++ accuracy combined with moderate computing times of 1-15 min per beam satisfy all clinical needs. VMC++ allows, for the first time, accurate routine dose evaluations of radiation therapy with electrons. Adequate positioning of the dose reference point is essential. Even small displacements may significantly influence the calculation of monitor units.     

Ewing's sarcoma of bone: Oncologic and functional results

This paper describes 29 patients with Ewing's sarcoma of bone treated between 1975 and 1990 at the University of Nijmegen Hospital, Nijmegen, The Netherlands. Osteomyelitis was the primary diagnosis in 24%. Treatment consisted of chemotherapy in combination with surgery and/or radiotherapy. Nine patients received radiotherapy only; five of them died of disease. Five patients underwent an intralesional excision; four of them died of disease. Twelve patients underwent a wide excision; there is no evidence of disease in any of them. Three patients underwent a radical disarticulation; all died of disease. The disease-free survival at 1.5 years was 66%. This figure at 5 years was 55%. After wide excision and reconstruction in tumors of expendable, femoral or radial bones good functional results were obtained in all cases. © 1995 Wiley-Liss, Inc.