Influence of the choice of software package on the outcome of semiquantitative MR myocardial perfusion analysis.

PURPOSE: To assess the repeatability and reproducibility of semiquantitative magnetic resonance (MR) perfusion analysis performed by using different software packages. MATERIALS AND METHODS: The study protocol was approved by the institutional ethics committee. Informed consent was obtained from each patient. Semiquantitative perfusion analysis was performed twice by two independent observers using four dedicated software packages. MR perfusion datasets originated from eight patients with known single-vessel disease who were scheduled for percutaneous coronary intervention (PCI) on the basis of coronary angiography findings. Each patient underwent two examinations: 1 day before and 1 day after PCI. Repeatability (intra- and interobserver agreements) and reproducibility (intersoftware agreement) were evaluated for perfusion upslope and myocardial perfusion reserve index with Student t test and Bland-Altman analyses. RESULTS: Intra- and interobserver agreements were good and comparable for repeated measurements within each individual software platform (mean differences < 6%, intraclass correlation coefficient [ICC] ≥ 0.68). However, the intersoftware variability was significant (limits of agreement ≥ 65%, ICC ≤ 0.67) such that the values produced with the different software packages are not interchangeable. CONCLUSION: The results indicate high repeatability within individual software but low reproducibility between different software packages, suggesting that within-group and/or sequential observation of semiquantitative perfusion parameters must be performed with the same software platform. Before semiquantitative perfusion analysis can be incorporated reliably into clinical studies, it is important to resolve the differences between the software packages.

Informatics in radiology: postprocessing pitfalls in using CT for automatic and semiautomatic determination of global left ventricular function.

Recent advances in technical capabilities of computed tomographic (CT) scanners, including an increasing number of detector rows, improved spatial and temporal resolution, and the development of retrospective gating, have allowed the acquisition of four-dimensional (4D) datasets of the beating heart. As a result, the heart can be visualized in different phases and CT datasets can be used to assess cardiac function. Many software packages currently exist that allow automatic or semiautomatic evaluation of left ventricular function on the basis of 4D CT datasets. The level of automation varies from extensive, completely manual segmentation by the user to fully automatic evaluation of left ventricular function without any user interaction. Although the reproducibility of functional parameter assessment is reported to be high and intersoftware variability low for larger groups of patients, significant differences can exist among measurements obtained with different software tools from the same dataset. Thus, careful review of automatically or semiautomatically obtained results is required.