Fast dynamic contrast‐enhanced lung MR imaging using k–t BLAST: A spatiotemporal perspective

Abstract

Dynamic contrast-enhanced MR imaging has long been an attractive alternative to measure pulmonary perfusion as it offers simultaneous acquisition of high-resolution anatomical images and various functional information without exposing to ionizing radiation. As higher temporal resolution in addition to simultaneous acquisition of more slices from different positions favors more precise diagnosis, rapid acquisition of multiple images during bolus contrast administration remains essential to pulmonary perfusion imaging. Nevertheless, the branching morphology together with asynchronization of contrast-enhanced pulmonary perfusion scattered among distinct blood vessels imposes difficulties to faster imaging. This work demonstrates that k-t broad-use linear acquisition speed-up technique (k-t BLAST), having substantial performance on accelerating cardiac cine imaging, can be applied to accelerate dynamic contrast-enhanced lung imaging up to a factor of 5 with errors less than 6% on five healthy subjects and less than 10% on 13 patients, respectively, in the overall signal intensity. Perfusion parameter estimates show somewhat less errors than those in overall signal intensity. Results from healthy subjects and two groups of patients with various diseases show high consistency between fully sampled datasets and their accelerated counterparts. These suggest feasibility of accelerated contrast-enhanced lung images in clinical examinations and potential of extending k-t BLAST into related applications. Magn Reson Med 67:786-792, 2012. V C 2011 Wiley Periodicals, Inc. Key words: lung; pulmonary perfusion; k-t BLAST; contrastenhanced MRI; image acceleration; spatiotemporal dynamic Pulmonary perfusion is a fundamental diagnostic indicator of many cardiopulmonary disorders (1,2), as lung perfusion links closely to ventilation and hence functionality of gas exchange. Although assessments of pulmonary perfusion were conventionally performed by nuclear scintigraphic techniques incorporating radioactive isotopes (such as Tc99m-MAA) (3) at the cost of radiation and limited spatial resolution, dynamic contrastenhanced (DCE) pulmonary MR imaging with bolus administration of exogenous contrast agent gradually became an attractive alternative with simultaneous acquisition of high-resolution anatomical images without exposure of ionization radiation. Patient studies have further shown the ability of DCE lung MR imaging to assist detection of pulmonary embolism (4,5), to evaluate postoperative lung function in lung cancer patients (6,7), and to assess complex pulmonary circulation in congenital heart diseases (8). The effectiveness DCE MR imaging, as demonstrated with comparable quality to the current gold standard (9,10) and with perfusion quantification validated by experimental animal model using invasive microsphere measurements (11), clearly reveals promising potential in the monitoring of pulmonary diseases (12).Acceleration using possible spatiotemporal redundancy, however, remains an important issue when adopting DCE MR imaging ...

Characterizing spatiotemporal information loss in sparse‐sampling‐based dynamic MRI for monitoring respiration‐induced tumor motion in radiotherapy

“…29 On the other hand, Hsu et al demonstrated that k-t factor of five could be used for contrast-enhanced lung perfusion measurement. 30 Thus, the selection of k-t acceleration factor must be based on the level of tolerance in the motion error as well as the image degradation for a specific purpose. The focus of present study is the application of k-t BLAST based dynamic MRI for the motion management for radiation treatment.…”

Pushing CT and MR Imaging to the Molecular Level for Studying the “Omics”: Current Challenges and Advancements

“…Due to the intrinsic physical limitation of MRI, the speed of data acquisition is always the problem comparing to CT. Hence, a number of acceleration techniques have been developed over the past four decades and the shortened acquisition time has greatly expanded clinical applications of MRI, especially for dynamic or time-resolved MRI, such as perfusion imaging [103–106], contrast-enhanced MR angiography [107–111], functional MRI [112, 113], and cardiac function examinations [114–117]. Those acceleration techniques could be divided into two categories: parallel imaging and dynamic acceleration.…”