The cristal (right superior septal) coronary artery and its relationship to anomalous left coronary origin.

The cristal artery is an occasional finding, being visible in around 3% of coronary angiograms, arising from the proximal right coronary artery (RCA) and passing downwards and forwards through the muscle of the crista superventricularis. It supplies a variable volume of the superior interventricular septum, and can contribute to collateralization of the other septal vessels. When part or all of the left coronary artery (LCA) arises anomalously from the right coronary sinus, its passage to the left may be in the same pathway as a cristal artery, bearing a tell-tale septal vessel arising from its proximal segment. This helps to differentiate it from one that has a higher pathway, running between the great vessels, and which may have a greater correlation with sudden cardiac death.

Diagnostic accuracy of CT angiography in acute gastrointestinal bleeding.

The aim of the study was to carry out a systematic review determining the accuracy of CT angiography in the diagnosis of acute gastrointestinal bleeding. A search of published work in Medline and manual searching of reference lists of articles was conducted. Studies were included if they compared CT angiography to a reference standard of upper gastrointestinal endoscopy, colonoscopy, angiography or surgery in the diagnosis of acute gastrointestinal bleeding. Eight published studies evaluating 129 patients were included. Data were used to form 2 x 2 tables. Computed tomography angiography showed pooled sensitivity of 86% (95% confidence interval 78-92%) and specificity of 95% (95% confidence interval 76-100%), without showing significant heterogeneity (chi(2) = 3.5, P = 0.6) and (chi(2) = 5.4, P = 0.6), respectively. Summary receiver operating characteristic analysis showed an area under the curve of 0.93. Computed tomography angiography is accurate in the diagnosis of acute gastrointestinal bleeding and can show the precise location and aetiology of bleeding, thereby directing further management. Strong recommendations for use of CT cannot be made from this review because of the methodological limitations and further large prospective studies are needed to define the role of CT in acute gastrointestinal bleeding.

Recognition and management of contrast media extravasation.

Intravenous contrast agents are frequent adjuncts used in diagnostic imaging. Despite the well-recognized complications of contrast media extravasation, its treatment remains an enigma to many. This article reviews the recognition, prevention and treatment options, with a summary of the contrast media extravasation policy implemented in our department.

Predicting memory performance in normal ageing using different measures of hippocampal size.

A number of different methods have been employed to correct hippocampal volumes for individual variation in head size. Researchers have previously used qualitative visual inspection to gauge hippocampal atrophy. The purpose of this study was to determine the best measure(s) of hippocampal size for predicting memory functioning in 102 community-dwelling individuals over 80 years of age. Hippocampal size was estimated using magnetic resonance imaging (MRI) volumetry and qualitative visual assessment. Right and left hippocampal volumes were adjusted by three different estimates of head size: total intracranial volume (TICV), whole-brain volume including ventricles (WB+V) and a more refined measure of whole-brain volume with ventricles extracted (WB). We compared the relative efficacy of these three volumetric adjustment methods and visual ratings of hippocampal size in predicting memory performance using linear regression. All four measures of hippocampal size were significant predictors of memory performance. TICV-adjusted volumes performed most poorly in accounting for variance in memory scores. Hippocampal volumes adjusted by either measure of whole-brain volume performed equally well, although qualitative visual ratings of the hippocampus were at least as effective as the volumetric measures in predicting memory performance in community-dwelling individuals in the ninth or tenth decade of life.

Contrast column interruption artefact in computed tomography pulmonary angiography.

Interruption of the contrast column during inspiration can lead to non-diagnostic CT pulmonary angiograms. The importance of this artefact will increase with more CT studies being performed for pulmonary embolism on multidetector row CT. We describe here an instance of such an artefact and discuss its aetiology.

Incidental heterotopic pregnancy demonstrated on magnetic resonance imaging.

We report a case of an assisted pregnancy in an asymptomatic woman who was found to have an extrauterine mass on ultrasound and MRI. This complex mass had equivocal imaging features and was found to be a ruptured ovarian ectopic pregnancy at surgery. This case illustrates that vigilance is required regarding the possibility of coexisting ectopic and intrauterine pregnancy following assisted conception, even in entirely asymptomatic cases.

Comparing white matter lesions on T2 and FLAIR MRI in the Sydney Older Persons Study.

There is suggestion that magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) sequence may be more accurate than T2 images in detecting white matter lesions (WML) in older people. Comparative ratings of these two image sequences have not been directly investigated in very old individuals to date. We compared the ratings of periventricular and deep WML on these two sequences in a sample of 111 community dwellers (mean age 85.5 years) using semiquantitative methods. Periventricular WML were as commonly detected on T2 as on FLAIR but were more severely rated on the latter sequence. No such bias was observed for the deep WML. With one exception, correlations between the two sets of measures were significant at the P < 0.001 level (range: 0.34-0.75). Intrarater reliability coefficients were moderate to excellent for most ratings. These results suggest that ratings performed on T2-weighted images to detect WML in very old individuals are very comparable with those performed on FLAIR images although FLAIR may allow a finer grading of periventricular lesions. Absence of FLAIR does not preclude the identification of WML in this population. These findings have clinical and epidemiological relevance where the acquisition of supplementary MRI data may not always be possible.

Allergic reactions to oral iodinated contrast agents: reactions to oral contrast.

Allergic reactions can occur with virtually all substances used in medicine. Recently there has been increasing recognition that iodinated oral contrast agents (oral contrast) used in radiology are also capable of inducing an allergic response. Fortunately these are rarely life-threatening. This paper discusses three cases of mild reactions to oral iodinated contrast (all for computed tomography (CT) scans). The Australian experience of these agents is also reviewed.

Hippocampal size and memory function in the ninth and tenth decades of life: the Sydney Older Persons Study.

OBJECTIVES: The purpose of this study was to define magnetic resonance imaging (MRI) correlates of normal brain ageing, with the specific objective of investigating whether the size of the hippocampus is selectively correlated with age related memory performance in non-demented individuals in their ninth and tenth decades of life. METHODS: Hippocampal size was estimated using MRI based volumetry and qualitative visual assessment in 102 community dwelling individuals aged between 81 and 94 years. Participants were evaluated on a variety of clinical and experimental instruments, including a comprehensive neuropsychological test battery. All participants underwent neurological examination, an extensive medical history was obtained, and an informant confirmed details of each participant's functional ability. RESULTS: Both visual and volumetric hippocampal measures were identified as robust predictors of memory performance, even when the influence of age related illnesses and sociodemographic variables was accounted for. When the sample was reduced to include the most cognitively healthy participants who were rated by an informant as showing no evidence of cognitive decline, the left hippocampal measures remained significant predictors of delayed retention of verbal material. CONCLUSIONS: These findings suggest that hippocampal volumes are selectively correlated with memory functioning in both normal and successful ageing.