Computer-Aided Diagnosis Improves Detection of Small Intracranial Aneurysms on MRA in a Clinical Setting

BACKGROUND AND PURPOSE:MRA is widely accepted as a noninvasive diagnostic tool for the detection of intracranial aneurysms, but detection is still a challenging task with rather low detection rates. Our aim was to examine the performance of a computer-aided diagnosis algorithm for detecting intracranial aneurysms on MRA in a clinical setting.MATERIALS AND METHODS:Aneurysm detectability was evaluated retrospectively in 48 subjects with and without computer-aided diagnosis by 6 readers using a clinical 3D viewing system. Aneurysms ranged from 1.1 to 6.0 mm (mean = 3.12 mm, median = 2.50 mm). We conducted a multireader, multicase, double-crossover design, free-response, observer-performance study on sets of images from different MRA scanners by using DSA as the reference standard. Jackknife alternative free-response operating characteristic curve analysis with the figure of merit was used.RESULTS:For all readers combined, the mean figure of merit improved from 0.655 to 0.759, indicating a change in the figure of merit attributable to computer-aided diagnosis of 0.10 (95% CI, 0.03–0.18), which was statistically significant (F_1,47 = 7.00, P = .011). Five of the 6 radiologists had improved performance with computer-aided diagnosis, primarily due to increased sensitivity.CONCLUSIONS:In conditions similar to clinical practice, using computer-aided diagnosis significantly improved radiologists'' detection of intracranial DSA-confirmed aneurysms of ≤6 mm.

Intracranial aneurysms are abnormal dilations of the cerebral arteries that may rupture and result in subarachnoid hemorrhage, a condition associated with high morbidity and mortality. The estimated prevalence of unruptured intracranial aneurysms in the population varies between 0.2% and 9% according to different postmortem and angiographic studies,¹ with most estimates in the 2%–3% range. The estimates of the risk of rupture of aneurysms are controversial,^2–5 but two-thirds of patients with aneurysm rupture either die or have serious morbidity.⁶While DSA remains the criterion standard for the detection of intracranial aneurysms, MRA is widely accepted as a noninvasive diagnostic tool. In recent years, due to the increasing use and availability of MRA, incidental unruptured aneurysms are detected more frequently than in the past.^1,7 Older studies specifically evaluating the detectability of untreated aneurysms by using MRA compared with DSA showed a sensitivity from 67%–89%,^8,9 but only 35%–56% for aneurysms <5 mm^9–11; more recent studies have shown a sensitivity as high as 96.7%, which is comparable with that of DSA.^12–14It is often difficult to detect small (<5–7 mm) or very small (<3 mm) aneurysms^15–17on maximum-intensity-projection images due to overlap of the aneurysm with adjacent arteries and to flow patterns that reduce signal. Aneurysms often occur at arterial branch points, where there is greater likelihood of vessel overlap. Additionally, TOF-MRA, the most common technique in clinical practice, is often limited by low signal intensity within the aneurysm due to irregular or slow flow.We have developed an algorithm that is capable of identifying regions that are suspicious for intracranial aneurysms on TOF-MRA with high sensitivity.¹⁸ It can be considered automated because no human input is required to produce its results. Previous computer-aided diagnosis (CAD) algorithms were evaluated on a few cases from a single MR imaging scanner, or they were not fully automatic.^19,20 In other studies, CAD did not detect small or fusiform types of aneurysms,²¹ or its effectiveness was not tested with a proper reader performance study.²² Although there have been several performance studies on CAD schemes described by Arimura et al^19,23 by using receiver operating characteristic curve analysis,^20,24 none of these studies used DSA as a standard of reference for the presence or absence of aneurysms; therefore, the true CAD accuracy remains unknown.We examined the practical use of our automated CAD scheme for detecting aneurysms by using DSA as the reference standard. We performed a retrospective multireader observer performance study by using MRA data from a variety of clinical sites with variable image quality.     

The philosophical and sociological context of mental health care legislation

This paper explores mental health legislation from a philosophical and sociological perspective. It is argued that mental health law exists primarily as a coercive social control instrument and that the maintenance of a separate legislative framework for the mentally ill is based upon dubious legal and philosophical grounds. The need for changes in mental health law has been accelerated by the move in Britain toward care in the community. One of the most important issues at the centre of the debate revolves around the concept of 'dangerousness' and mental disorder. The research into the extent to which the risk of violence can be predicted appears problematic from a reform perspective. Prediction is considered to be the overriding problem that leads to a violation of patients' civil rights, especially in relation to black and ethnic minority groups. Equity in law is necessary for the protection of patient's rights and particularly for the protection of those people who enter mental health care systems concerned with issues of control at the expense of care.     

The origins of insane asylums in England during the 19th century: a brief sociological review

This paper explores the origins of insane asylums in 19th century England by comparing the official 'received' medically dominated perspective with an alternative sociological perspective The major structural changes in provision are addressed as the focus for analysing the differing histories A brief review is presented of the responses to insane people prior to the national asylum programme following the 1845 Lunacy Act, and of the reform logic that underpinned asylum care The alternative sociological perspective presents the origins of psychiatric asylums as part of the social and economic changes occuring generally at that time As such the origins of insane asylums are presented as part of a state-guided 'sanitary'movement which included poor, criminal and insane people within its remit The effect of state-guided correction was the segregation of insane people from both the general population and other deviants who were formerly classed together Insane people are thus presented as a group of deviants who departed most radically from the 'rational individualist' qualities of self-control, predictability and responsibility required in the industrialized world of capital social relations that emerged during the last century     

No effect of an oleoylethanolamide-related phospholipid on satiety and energy intake: a randomised controlled trial of phosphatidylethanolamine

Background  

Phosphatidylethanolamine (PE) is a phospholipid which is biosynthesized into long chain N-acylethanolamines (NAEs) including oleoylethanolamide (OEA), a known inhibitor of food intake. The aim of this study was to investigate whether PE-containing lipids can also inhibit intake. This was a 4 treatment intervention where 18 male participants were given a high-fat test breakfast (2.5MJ, 53 en% fat) containing (i) high-phospholipid, high-PE lipid (ii) high-phospholipid, medium-PE lipid (iii) no-phospholipid, no-PE control lipid or (iv) water control, in a randomised cross-over. Visual analogue scales (VAS) were used to assess post-ingestive hunger and satiety, and energy intake (EI) was measured at an ad libitum lunch meal after 3.5hours.     

Diatrizoate enemas: facts and fallacies of colonic toxicity

Rats were given enemas of Gastrografin in two strengths, Renografin--76, and Tween--80 in a 10% dilution. There were no deleterious effects on the colons with these media used in volumes to fill the colon. Severe changes resulted from volumes which produced overdistention.