Chronic thromboembolic pulmonary hypertension (CTEPH) - potential role of multidetector-row CT (MD-CT) and MR imaging in the diagnosis and differential diagnosis of the disease.

Chronic thromboembolic pulmonary hypertension (CTEPH) can be defined as pulmonary hypertension (resting mean pulmonary arterial pressure of 25 mm Hg or more determined at right heart catheterization) with persistent pulmonary perfusion defects. It is a rare, but underdiagnosed disease with estimated incidences ranging from 0.5% to 3.8% of patients after an acute pulmonary embolism (PE), and in up to 10% of those with a history of recurrent PE. CTEPH is the only form of pulmonary hypertension that can be surgically treated leading to normalization of pulmonary hemodynamics and exercise capacity in the vast majority of patients. The challenges for imaging in patients with suspected CTEPH are fourfold: the imaging modality should have a high diagnostic accuracy with regard to the presence of CTEPH and allow for differential diagnosis. It should enable detection of patients suitable for PEA with great certainty, and allow for quantification of PH by measuring pulmonary hemodynamics (mPAP and PVR), and finally, it can be used for therapy monitoring. This overview tries to elucidate the potential role of ECG-gated multidetector CT pulmonary angiography (MD-CTPA) and MR imaging, and summarizes the most important results that have been achieved so far. Generally speaking, ECG-gated MD-CTPA is superior to MR in the assessment of parenchymal and vascular pathologies of the lung, and allows for the assessment of cardiac structures. The implementation of iodine maps as a surrogate for lung perfusion enables functional assessment of lung perfusion by CT. MR imaging is the reference standard for the assessment of right heart function and lung perfusion, the latter delineating typical wedge-shaped perfusion defects in patients with CTEPH. New developments show that with MR techniques, an estimation of hemodynamic parameters like mean pulmonary arterial pressure and pulmonary vascular resistance will be possible. CT and MR imaging should be considered as complementary investigations providing comprehensive information in patients with CTEPH.

Two-dimensional surface magnetism in the bulk paramagnetic intermetallic alloy CoAl(100).

Utilizing a combination of the in situ magneto-optical Kerr effect and scanning tunneling microscopy and spectroscopy measurements, we show that the (100) surface of the B2 bulk paramagnetic CoAl is an excellent representation of a two-dimensional ferromagnet. The order-parameter critical exponent beta=0.22+/-0.02 is determined, which is the universal signature of a finite-size two-dimensional XY behavior. The Curie temperature is found to be T(c)=90 K. The magnetism can be explained by the appearance of Co antisite atoms at the surface.

The use of conjoint analysis to elicit community preferences in public health research: a case study of hospital services in South Australia.

AIMS: To demonstrate the use of conjoint analysis (CA) in public health research through a survey of the South Australian community about aspects of their public hospital services. METHODS: A series of focus groups determined the most important attributes in choice of hospital services. These were built into a CA survey, using the discrete choice approach. The survey was posted to a representative sample of 700 South Australians. Theoretical validity, internal consistency and non-response bias were all investigated. RESULTS: Some 231 individuals returned the questionnaire. The attribute, 'improvement in complication rates' was positively associated with choice of hospital. Three attributes were found to be negatively associated with such choice: 'waiting times for casualty', 'waiting times for elective surgery' and, anomalously, 'parking and transport facilities'. 'Travel time' and the cost attribute, 'Medicare levy' were not statistically significant. Trade-offs between the significant attributes were estimated, as were satisfaction or utility scores for different ways of providing hospital services. Results concerning internal consistency and internal validity were encouraging, but some potential for non-response bias was detected. CONCLUSION: A high premium is placed on the quality of hospital care and members of the community are prepared to choose between hospitals largely on the basis of outcomes and length of waiting times for elective surgery and in casualty. IMPLICATIONS: CA can yield potentially policy-relevant information about community preferences for health services.

Post-transfusion purpura (PTP) associated with anti-HPA-1a, anti-HPA-2b and anti-HPA-3a antibodies.

The serum from an 85-year-old man with a clinical diagnosis of post-transfusion purpura (PTP) was investigated for the presence of platelet-specific antibodies. Clinically, the case was typical of PTP but, unusually, the serum was found to contain multiple platelet-specific alloantibodies. Anti-HPA-1a, anti-HPA-2b and anti-HPA-3a antibodies were detected together with multispecific anti-HLA (class I) antibodies. Additional (but weaker) antibody reactivity was also observed with platelet glycoproteins (Gp) IIb/IIIa, GpIb and GpIa/IIa which lacked the antigens recognized by the alloantibodies, suggesting the presence of auto- or cross-reacting antibodies. The patient's genotype was HPA-1b/1b, HPA-2a/2a, HPA-3b/3b, HPA-5a/5b and was consistent with the platelet alloantibodies detected. The patient made a complete recovery following treatment with intravenous gamma-globulin.