A comparison of treating physician versus independent core lab assessments of post-aneurysm treatment imaging outcomes: an analysis of prospectively collected data from a randomized trial

OBJECTIVE

Aneurysm occlusion has been used as surrogate marker of aneurysm treatment efficacy. Aneurysm occlusion scales are used to evaluate the outcome of endovascular aneurysm treatment and to monitor recurrence. These scales, however, require subjective interpretation of imaging data, which can reduce the utility and reliability of these scales and the validity of clinical studies regarding aneurysm occlusion rates. Use of a core lab with independent blinded reviewers has been implemented to enhance the validity of occlusion rate assessments in clinical trials. The degree of agreement between core labs and treating physicians has not been well studied with prospectively collected data.

METHODS

In this study, the authors analyzed data from the Hydrogel Endovascular Aneurysm Treatment (HEAT) trial to assess the interrater agreement between the treating physician and the blinded core lab. The HEAT trial included 600 patients across 46 sites with intracranial aneurysms treated with coiling. The treating site and the core lab independently reviewed immediate postoperative and follow-up imaging (3-12 and 18-24 months, respectively) using the Raymond-Roy occlusion classification (RROC) scale, Meyer scale, and recanalization survey. A post hoc analysis was performed to calculate interrater reliability using Cohen's kappa. Further analysis was performed to assess whether degree of agreement varied on the basis of various factors, including scale used, timing of imaging, size of the aneurysm, imaging modality, location of the aneurysm, dome-to-neck ratio, and rupture status.

RESULTS

Minimal interrater agreement was noted between the core lab reviewers and the treating physicians for assessing aneurysm occlusion using the RROC grading scale (k = 0.39, 95% CI 0.38-0.40) and Meyer scale (k = 0.23, 95% CI 0.14-0.38). The degree of agreement between groups was slightly better but still weak for assessing recanalization (k = 0.45, 95% CI 0.38-0.52). Factors that significantly improved degree of agreement were scales with fewer variables, greater time to follow-up, imaging modality (digital subtraction angiography), and wide-neck aneurysms.

CONCLUSIONS

Assessment of aneurysm treatment outcome with commonly used aneurysm occlusion scales suffers from risk of poor interrater agreement. This supports the use of independent core labs for validation of outcome data to minimize reporting bias. Use of outcome tools with fewer point categories is likely to provide better interrater reliability. Therefore, the outcome assessment tools are ideal for clinical outcome assessment provided that they are sensitive enough to detect a clinically significant change.

How medicinal chemists learned about log P

Although log P is now recognized to be a key factor that determines the bioactivity of a molecule, the focus of medicinal chemists on hydrophobicity and log P started with the quantitative structure-activity relationships (QSAR) publications of Hansch and Fujita. Their original publication represents a dramatic change of focus to incorporate consideration of log P after a decade of work unsuccessfully attempting to use the Hammett equation to explain the structure-activity relationships of plant growth regulators. QSAR allows one to explore the quantitative relationship between log P and biological activity even when other factors also influence potency. In particular, Hansch's publications of thousands of QSAR equations demonstrate that a relationship of biological activity with log P is indeed a general phenomenon. Hansch's group also provided data and tools that enable others to explore the relationship between log P and the biological activity of compounds of interest.

Social Skills: Adolf Meyer's Revision of Clinical Skill for the New Psychiatry of the Twentieth Century

Adolf Meyer (1866-1950) exercised considerable influence over the development of Anglo-American psychiatry during the first half of the twentieth century. The concepts and techniques he implemented at his prominent Phipps Psychiatric Clinic at Johns Hopkins remain important to psychiatric practice and neuro-scientific research today. In the 1890s, Meyer revised scientific medicine's traditional notion of clinical skill to serve what he called the 'New Psychiatry', a clinical discipline that embodied social and scientific ideals shared with other 'new' progressive reform movements in the United States. This revision conformed to his concept of psychobiology - his biological theory of mind and mental disorders - and accorded with his definition of scientific medicine as a unity of clinical-pathological methods and therapeutics. Combining insights from evolutionary biology, neuron theory and American pragmatist philosophy, Meyer concluded that subjective experience and social behaviour were functions of human biology. In addition to the time-honoured techniques devised to exploit the material data of the diseased body - observing and recording in the clinic, dissecting in the morgue and conducting histological experiments in the laboratory - he insisted that psychiatrists must also be skilled at wielding social interaction and interpersonal relationships as investigative and therapeutic tools in order to conceptualise, collect, analyse and apply the ephemeral data of 'social adaptation'. An examination of his clinical practices and teaching at Johns Hopkins between 1913 and 1917 shows how particular historical and intellectual contexts shaped Meyer's conceptualisation of social behaviour as a biological function and, subsequently, his new vision of clinical skill for twentieth-century psychiatry.

STFT or CWT for the detection of Doppler ultrasound embolic signals

Aiming reliable detection and localization of cerebral blood flow and emboli, embolic signals were added to simulated middle cerebral artery Doppler signals and analysed. Short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were used in the evaluation. The following parameters were used in this study: the powers of the embolic signals added were 5, 6, 6.5, 7, 7.5, 8 and 9 dB; the mother wavelets for CWT analysis were Morlet, Mexican hat, Meyer, Gaussian (order 4) and Daubechies (orders 4 and 8); and the thresholds for detection (equated in terms of false positive, false negative and sensitivity) were 2 and 3.5 dB for the CWT and STFT, respectively. The results indicate that although the STFT allows accurately detecting emboli, better time localization can be achieved with the CWT. Among the CWT, the current best overall results were obtained with Mexican Hat mother wavelet, with optimal results for sensitivity (100% detection rate) for nearly all emboli power values studied.