Semiautomatic evaluation of left ventricular diastolic function with cine magnetic resonance imaging.

RATIONALE AND OBJECTIVES: Cine magnetic resonance (MR) imaging is a relatively new technique that can be used to study cardiac function with high spatial and temporal resolution. However, detailed functional analysis of the entire cardiac cycle with cine MR imaging is time consuming and labor intensive. We analyzed diastolic function using a semiautomatic routine that reduces the time necessary for analysis. METHODS: Twenty subjects (10 normal control subjects and 10 patients with isolated diastolic dysfunction) were examined. Short-axis cine MR images were obtained at 32 phases of the cardiac cycle. A semiautomatic boundary-finding routine was used to determine left ventricular (LV) volumes at each phase. Volume-versus-time and first-derivative curves were created from these data. Several parameters derived from the MR imaging curves were used to characterize diastole. RESULTS: Two parameters--the ratio of early peak filling rate to late peak filling rate and the percentage of filling during early diastole--perfectly distinguished subjects with LV diastolic dysfunction from the normal control subjects. The semiautomatic analysis method substantially reduced the time necessary for analyzing the MR imaging data, compared with manual analysis. CONCLUSION: Cine MR imaging, especially with time-saving techniques such as our service automatic analysis method, has promise as a research and clinical tool in evaluating LV diastolic function.

Fast, interactive algorithm for segmentation of a series of related images: application to volumetric analysis of MR images of the heart.

Magnetic resonance (MR) cine images of the beating heart have excellent spatial and temporal resolution. Extracting the boundaries of the heart from MR images for volumetric measurements is of considerable interest; however, since the number of images involved is large, tracing the boundaries by hand is tedious and prohibitively time consuming. The authors have developed an interactive method of boundary detection that uses the correlation between the cardiac boundaries on temporally or spatially adjacent images to increase the speed of the process and reproducibility of the measurement. A simulated cine MR study of a phantom (total of 155 images) and cardiac cine studies of two patients (192 images each) were analyzed by two independent observers. Analysis of the phantom data was completed in 5.6 minutes (2.16 seconds per image) by observer 1 and 6.3 minutes (2.4 seconds per image) by observer 2. The percent measurement errors for 31 phantom volumes (30-120 mL) were 0.96% and 0.83% for observers 1 and 2, respectively. The observers analyzed the patient studies in 14-23 minutes (4.4-7.2 seconds per image), with interobserver variabilities of 5.8% and 3.7% for the two patients, respectively. The authors conclude that their flexible, semiautomatic, interactive algorithm allows rapid and reproducible detection of structural boundaries.