New imaging techniques for assessing cardiac function

Use of noninvasive tools in primary pulmonary hypertension to assess the correlation of right ventricular function with functional capacity and to predict outcome

Most patients with Primary Pulmonary Hypertension (PPH) have severe exertional limitation which ultimately leads to right heart failure and death. The purpose of the study was to assess the correlation between right ventricular (RV) systolic and diastolic noninvasive variables and exercise tolerance, as well as the predictors of adverse outcome in treated patients.

METHODS

We prospectively studied 29 patients, 17 with PPH and 12 with PPH due to collagen disease. RV parameters were assessed by echocardiography and Radionuclide ventriculography. Pulmonary function and clinical profile were assessed by 6 min walk test and NYHA class. The patients were followed-up during 2 years for cardiac death and cardiac deterioration.

RESULTS

Mean age was 51 +/- 15 years, 22 (78%) women. NYHA class1 in 2 pts, class 2 in 17, class 3 in 8 and class 4 in 2 pts. Pulmonary function (DLCO) was low in 25 (86%) pts, mean 22 +/- 48%. Six minutes walk distance was 358 +/- 132 m, RVEF was 34 +/- 11% (range 16-51%). Among RV variables, RVEF, RA area and TR were independently correlated to 6 min walk. Within follow up of 2 years, there were 10 patients with adverse outcome (4 deaths and 6 deteriorated to NYHA class 3 and 4). Among all clinical and noninvasive variables, RVEF only was correlated to adverse outcome.

CONCLUSION

The noninvasive tests of RVEF, RA size and TR were closely correlated to exercise tolerance. However, among the various clinical, functional and RV variables, RVEF was the only variable correlated with adverse outcome in pts with PPH.

Cardiovascular MR imaging: technique optimization and detection of disease in clinical practice

Magnetic resonance (MR) imaging has emerged as an important and growing means of cardiovascular imaging, with many advantages over other radiologic modalities, including excellent spatial and temporal resolution, lack of ionizing radiation, and noninvasiveness. In this article, the utility of MR imaging in cardiovascular imaging and in the diagnosis of cardiovascular disease will be discussed. MR techniques for evaluating the heart and vasculature will be described, and troubleshooting techniques will be presented. Imaging findings in congenital anomalies such as septal defects, patent ductus arteriosus, transposition of the great arteries, and tetralogy of Fallot will be identified. Valvular lesions and methods for evaluating valvular function will be discussed. MR imaging findings in acquired disorders such as aneurysms and pericardial disease will be described.

Statistical description of interrater variability in ordinal ratings

Ordinal categorical assessments are common in medical practice and in research. Variability in such measurements amongst raters making the assessments can be problematic. In this paper we consider how such variability can be described statistically. We review three current approaches, including kappa-type statistics, loglinear models for agreement, and latent class agreement models, and discuss their limitations. We present a new graphical approach to describing interrater variability that involves a simple frequency distribution display of the category probabilities. The method enables description of interrater variability when raters are a random sample from some population as opposed to the traditional setting in which only a few selected raters provide assessments. Advantages of this approach relative to current approaches include the following: (1) it provides a simple visual summary of the rating data, (2) description is closely linked to familiar methods for describing variability in continuous measurements, (3) interpretation is straightforward, and (4) a large sample of raters can be accommodated with ease. We illustrate the method on simulated ordinal data representing radiologists' ratings of mammography images and on rating data from a national image reading study of mammography screening.