Nipah virus causes a severe, rapidly progressive encephalitis with a high mortality rate and features that suggest involvement of the brain stem. The infection is associated with recent contact with pigs.

An outbreak of infection with the Nipah virus, a novel paramyxovirus, occurred among pig farmers between September 1998 and June 1999 in Malaysia, involving 265 patients with 105 fatalities. This is a follow-up study 24 months after the outbreak. Twelve survivors (7.5%) of acute encephalitis had recurrent neurological disease (relapsed encephalitis). Of those who initially had acute nonencephalitic or asymptomatic infection, 10 patients (3.4%) had late-onset encephalitis. The mean interval between the first neurological episode and the time of initial infection was 8.4 months. Three patients had a second neurological episode. The onset of the relapsed or late-onset encephalitis was usually acute. Common clinical features were fever, headache, seizures, and focal neurological signs. Four of the 22 relapsed and late-onset encephalitis patients (18%) died. Magnetic resonance imaging typically showed patchy areas of confluent cortical lesions. Serial single-photon emission computed tomography showed the evolution of focal hyperperfusion to hypoperfusion in the corresponding areas. Necropsy of 2 patients showed changes of focal encephalitis with positive immunolocalization for Nipah virus antigens but no evidence of perivenous demyelination. We concluded that a unique relapsing and remitting encephalitis or late-onset encephalitis may result as a complication of persistent Nipah virus infection in the central nervous system.

MR imaging is a sensitive and specific diagnostic tool for evaluating Nipah encephalitis.

A recognized cause of incomplete or cancelled MRI examinations is anxiety and claustrophobic symptoms in patients undergoing MR scanning. This appears to be a problem in many MRI centres in Western Europe and North America, where it is said to be costly in terms of loss of valuable scan time, and has led to researchers suggesting several anxiety-reducing approaches for MRI. To determine the incidence of failed MRI examination among our patients and if there are any associations with a patient's sex, age and education level, we studied claustrophobia that led to premature termination of the MRI examination in the University Malaya Medical Centre (UMMC) in 3324 patients over 28 months. The incidence of failed MRI examinations due to claustrophobia in the UMMC was found to be only 0.54%. There are associations between claustrophobia in MRI with the patients' sex, age and level of education. The majority of those affected were male patients and young patients in the 25-45-years age group. The patients' education level appears to be the strongest association with failed MRI examinations due to claustrophobia, where the majority of the affected were highly educated individuals. Claustrophobia in MRI is more of a problem among the educated individuals or patients from a higher socio-economic group, which may explain the higher incidence in Western European and North American patients.

A baby boy who had a left facial mass detected on antenatal ultrasound was delivered by Caesarian section after foetal distress was detected. Imaging investigations by plain radiographs and MRI showed a large mass with calcifications, soft tissue, fat and fluid components. A total surgical excision was perfomed and histology examination showed teratoma with no malignant features. Two weeks postoperatively, there was rapid recurrence of the tumour with intracranial involvement and obstructive hydrocephalus shown on MRI. The tumour was inoperable at surgery and the baby subsequently died at 5 weeks of life. This case describes the clinical course and imaging features of a neonatal epignathus teratoma with malignant and aggressive features.

Many potential pitfalls and artefacts have been described in PET imaging that uses F-18 fluorodeoxyglucose (FDG). Normal uptake of FDG occurs in many sites of the body and may cause confusion in interpretation particularly in oncology imaging. Clinical correlation, awareness of the areas of normal uptake of FDG in the body and knowledge of variation in uptake as well as benign processes that are FDG avid are necessary to avoid potential pitfalls in image interpretation. In this context, optimum preparation of patients for their scans can be instituted in an attempt to reduce the problem. Many of the problems and pitfalls associated with areas of normal uptake of FDG can be solved by using PET CT imaging. PET CT imaging has the ability to correctly attribute FDG activity to a structurally normal organ on CT. However, the development of combined PET CT scanners also comes with its own specific problems related to the combined PET CT technique. These include misregistration artefacts due to respiration and the presence of high density substances which may lead to artefactual overestimation of activity if CT data are used for attenuation correction.

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Objectives The purpose of this study was to test the hypothesis that quantitative ultrasound properties of the calcaneus in Southeast Asian children treated for thalassemia have different characteristics than those of their healthy counterparts and thereby can be used for assessing the risk of osteoporosis. Methods Broadband ultrasound attenuation and the speed of sound were measured from groups of thalassemic and healthy children and compared with bone mineral density (BMD) estimated from dual‐energy X‐ray absorptiometry to determine intergroup and intragroup dependencies of the measurements and variations with differences in sex and anthropometric characteristics. Results Broadband ultrasound attenuation and speed of sound measurements were found to be independent of sex but dependent on age in the thalassemic children. Consistently, broadband ultrasound attenuation had lower values and the speed of sound had higher values compared with those of the healthy children in each age group. Broadband ultrasound attenuation correlated well with the speed of sound and also with age, weight, and height, but the speed of sound did not show an association with these parameters. Broadband ultrasound attenuation correlated moderately with BMD in the lumbar spine and whole body, but the corresponding association was much weaker for the speed of sound. In the thalassemic children, both broadband ultrasound attenuation and BMD increased with age as they grew older but not fast enough compared with the healthy children, and the risk of osteoporosis was greater at older ages. Conclusions Calcaneal quantitative ultrasound may be used as a diagnostic screening tool for assessing the bone status in thalassemic Southeast Asian children and for deciding whether further dual‐energy X‐ray absorptiometry is needed, particularly in those who are at a greater risk for osteoporosis as identified by low body weight and height.