Double-outlet right ventricle: Morphologic demonstration using nuclear magnetic resonance imaging

Sixteen patients with double-outlet right ventricle, aged 1 week to 29 years (median 5 months), were studied with a 1.5 tesla nuclear magnetic resonance (NMR) imaging scanner. Two-dimensional echocardiography was performed in all patients. Thirteen patients underwent angiography, including nine who underwent subsequent surgical correction. Three patients underwent postmortem examination.Small children and infants were scanned inside a 32 cm diameter proton head coil. Multiple 5 mm thick sections separated by 0.5 mm and gated to the patient's electrocardiogram were acquired with a spin-echo sequence and an echo time of 30 ms. A combination of standard and oblique imaging planes was used. Imaging times were <90 min. The NMR images were technically unsuitable in one patient because of excessive motion artifact.In the remaining patients, the diagnosis of double outlet right ventricle was confirmed and correlated with surgical and postmortern findings. The NMR images were particularly valuable in demonstrating the interrelations between the great arteries and the anatomy of the outlet septum and the spatial relations between the ventricular septal defect and the great arteries. Although the atrioventricular (AV) valves were not consistently demonstrated, NMR imaging in two patients identified abnormalities of the mitral valve that were not seen with two-dimensional echocardiography. In one patient who had a superoinferior arrangement of the ventricles, NMR imaging was the most useful imaging technique for demonstrating the anatomy.In patients with double-outlet right ventricle, NMR imaging can provide clinically relevant and accurate morphologic information that may contribute to future improvement in patient management

Detecting facet joint and lateral mass injuries of the subaxial cervical spine in major trauma patients

Study Design: Radiologic imaging measurement study. Purpose: To assess the accuracy of detecting lateral mass and facet joint injuries of the subaxial cervical spine on plain radiographs using computed tomography (CT) scan images as a reference standard; and the integrity of morphological landmarks of the lateral mass and facet joints of the subaxial cervical spine. Overview of Literature: Injuries of lateral mass and facet joints potentially lead to an unstable subaxial cervical spine and concomitant neurological sequelae. However, no study has evaluated the accuracy of detecting specific facet joint injuries. Methods: Eight spinal surgeons scored four sets of the same, randomly re-ordered, 30 cases with and without facet joint injuries of the subaxial cervical spine. Two surveys included conventional plain radiographs series (test) and another two surveys included CT scan images (reference). Facet joint injury characteristics were assessed for accuracy and reliability. Raw agreement, Fleiss kappa, Cohen's kappa and intraclass correlation coefficient statistics were used for reliability analysis. Majority rules were used for accuracy analysis. Results: Of the 21 facet joint injuries discerned on CT scan images, 10 were detected in both plain radiograph surveys (sensitivity, 0.48; 95% confidence interval [CI], 0.26-0.70). There were no false positive facet joint injuries in either of the first two X-ray surveys (specificity, 1.0; 95% CI, 0.63-1.0). Five of the 11 cases with missed injuries had an injury below the lowest visible articulating level on radiographs. CT scan images resulted in superior inter- and intra-rater agreement values for assessing morphologic injury characteristics of facet joint injuries. Conclusions: Plain radiographs are not accurate, nor reliable for the assessment of facet joint injuries of the subaxial cervical spine. CT scans offer reliable diagnostic information required for the detection and treatment planning of facet joint injuries.Joost Johannes van Middendorp, Ian Cheung, Kristian Dalzell, Hamish Deverall, Brian J.C. Freeman, Stephen A.C. Morris, Simon J.I. Sandler, Richard Williams, Y.H. Yau, Ben Gos

The Localization Transition of the Two-Dimensional Lorentz Model

We investigate the dynamics of a single tracer particle performing Brownian motion in a two-dimensional course of randomly distributed hard obstacles. At a certain critical obstacle density, the motion of the tracer becomes anomalous over many decades in time, which is rationalized in terms of an underlying percolation transition of the void space. In the vicinity of this critical density the dynamics follows the anomalous one up to a crossover time scale where the motion becomes either diffusive or localized. We analyze the scaling behavior of the time-dependent diffusion coefficient D(t) including corrections to scaling. Away from the critical density, D(t) exhibits universal hydrodynamic long-time tails both in the diffusive as well as in the localized phase.Comment: 13 pages, 7 figures

Explaining state development: Indonesia from its pre-independence origins to contemporary democracy.

Explaining State Development: Indonesia from Pre-Independence Origins to Contemporary Democracy. This thesis uses the Indonesian case to present a new paradigm for explaining the state development of new or relatively new (post-World War II) states. The first chapter describes this paradigm of organic and mechanical types of state development, argues that the development of the Indonesian state from the 1950s to 1990s is a good example of the mechanical type of development and shows how this can be confirmed by assessing and comparing the capabilities of the four different versions of a modern state developed by Indonesia since independence. The next chapter examines Indonesia’s pre-independence debates about the form of state to be adopted, which led to Indonesia accepting a Western model of the state that has since undergone a development process involving four different versions of a ‘modern’ state. These four versions of the state are defined according to their type of regime and policymaking institutions: I) parliamentary democracy, II) Sukarno’s civilian presidential monarchy, III) Suharto’s military presidential monarchy and IV) presidential democracy. Chapters Three to Six assess and compare these four versions’ capability in three key areas: 1) achieving legal legitimacy, 2) control of the military and 3) dealing with political disorder – a crucial area of state capability that requires two chapters. Then Chapter Seven examines and explains the pre-democratic origins of the present version of the Indonesian state, the presidential democracy of Version IV. The Conclusion collates the findings of Chapters Three to Six on capabilities and summarises the arguments of Chapters Two and Seven regarding the 1940s acceptance of the Western model of the state and the late 1990s opportunity for democratisation. Finally, there is a concluding assessment of the potential of the organic/mechanical typology as a new paradigm for studying state development in other countries, regions and eras