AimTo assess intervendor agreement of cardiovascular magnetic resonance feature tracking (CMR-FT) and to study the impact of repeated measures on reproducibility.Materials and methodsTen healthy volunteers underwent cine imaging in short-axis orientation at rest and with dobutamine stimulation (10 and 20 μg/kg/min). All images were analysed three times using two types of software (TomTec, Unterschleissheim, Germany and Circle, cvi42, Calgary, Canada) to assess global left ventricular circumferential (Ecc) and radial (Err) strains and torsion. Differences in intra- and interobserver variability within and between software types were assessed based on single and averaged measurements (two and three repetitions with subsequent averaging of results, respectively) as determined by Bland–Altman analysis, intraclass correlation coefficients (ICC), and coefficient of variation (CoV).ResultsMyocardial strains and torsion significantly increased on dobutamine stimulation with both types of software (p<0.05). Resting Ecc and torsion as well as Ecc values during dobutamine stimulation were lower measured with Circle (p<0.05). Intra- and interobserver variability between software types was lowest for Ecc (ICC 0.81 [0.63–0.91], 0.87 [0.72–0.94] and CoV 12.47% and 14.3%, respectively) irrespective of the number of analysis repetitions. Err and torsion showed higher variability that markedly improved for torsion with repeated analyses and to a lesser extent for Err. On an intravendor level TomTec showed better reproducibility for Ecc and torsion and Circle for Err.ConclusionsCMR-FT strain and torsion measurements are subject to considerable intervendor variability, which can be reduced using three analysis repetitions. For both vendors, Ecc qualifies as the most robust parameter with the best agreement, albeit lower Ecc values obtained using Circle, and warrants further investigation of incremental clinical merit.

The purpose of this study was to present the prebolus technique for quantitative multislice myocardial perfusion imaging. In quantitative MR perfusion studies the maximum contrast agent dose is limited by the requirement to determine the arterial input function (AIF). The prebolus technique consists of two consecutive contrast agent administrations. The AIF is determined from a first low-dose bolus, while a second, high-dose bolus allows the measurement of the myocardium with improved signal increase. The results of the prebolus technique using a multislice saturation recovery trueFISP sequence in healthy volunteers are presented. In comparison to a standard dose of 3 ml Gd-DTPA, perfusion values are maintained while the signal increase in the concentration time courses was considerably improved, accompanied by reduced standard deviations of the obtained perfusion values (0.72 ؎ 0.13 ml/g/min for 1 ml/8 ml and 0.67 ؎ 0.10 ml/g/min for 1 ml/12 ml Gd-DTPA, respectively The clinical practicability of first-pass contrast-enhanced myocardial perfusion MRI has been improved in the last years by a number of technical changes of the acquisition sequences (1). Consequently, clinical first-pass perfusion studies could be performed for the primary diagnosis of coronary artery disease, as well as for the detection of myocardial viability (2,3). Different strategies to determine quantitative values of myocardial perfusion in humans have been proposed (4 -9) and normal values for healthy human volunteers have been reported (5-9). A prerequisite for perfusion quantification is the determination of the arterial input function (AIF). But saturation effects allow the determination of the AIF only for low concentrations of contrast agent (10), while a high dose leads to improved signal-to-noise ratio (SNR) in the myocardium (11). The combination of the advantages of both doses has been shown in an animal study (12). In this work the prebolus technique was applied to humans. A multislice version using a saturation recovery technique was implemented for quantitative measurement of myocardial perfusion in healthy volunteers. MATERIALS AND METHODS In Vivo Perfusion ImagingThis study was approved by our institution's Ethics Committee and written informed consent was obtained from all 11 volunteers (eight male, three female, age 24 Ϯ 4 years). All measurements were carried out on a clinical 1.5 T whole-body scanner (Magnetom Symphony, Siemens Medical Solutions, Erlangen, Germany) using a 12-element body phased array coil. First-pass perfusion images were acquired with an arrhythmia-insensitive multislice, saturation recovery trueFISP imaging technique (13). The following sequence parameters were chosen: repetition time 2.6 ms, echo time 1.1 ms, delay between saturation and sampling of center of k-space 110 ms, flip angle 50°, threequarters Fourier acquisition, number of phase encoding lines 60, FOV 340 mm with reduction to 3/4, i.e., 255 mm, in phase-encoding direction, slice thickness 8 mm. Forty consecutive images were acquired for ea...

Obtaining functional information on the human lung is of tremendous interest in the characterization of lung defects and pathologies. However, pulmonary ventilation and perfusion maps usually require contrast agents and the application of electrocardiogram (ECG) triggering and breath holds to generate datasets free of motion artifacts. This work demonstrates the possibility of obtaining highly resolved perfusion-weighted and ventilation-weighted images of the human lung using proton MRI and the SElf-gated Non-Contrast-Enhanced FUnctional Lung imaging (SENCEFUL) technique. The SENCEFUL technique utilizes a two-dimensional fast low-angle shot (FLASH) sequence with quasi-random sampling of phase-encoding (PE) steps for data acquisition. After every readout, a short additional acquisition of the non-phase-encoded direct current (DC) signal necessary for self-gating was added. By sorting the quasi-randomly acquired data according to respiratory and cardiac phase derived from the DC signal, datasets of representative respiratory and cardiac cycles could be accurately reconstructed. By application of the Fourier transform along the temporal dimension, functional maps (perfusion and ventilation) were obtained. These maps were compared with dynamic contrast-enhanced (DCE, perfusion) as well as standard Fourier decomposition (FD, ventilation) reference datasets. All datasets were additionally scored by two experienced radiologists to quantify image quality. In addition, one initial patient examination using SENCEFUL was performed. Functional images of healthy volunteers and a patient diagnosed with hypoplasia of the left pulmonary artery and left-sided pulmonary fibrosis were successfully obtained. Perfusion-weighted images corresponded well to DCE-MRI data; ventilation-weighted images offered a significantly better depiction of the lung periphery compared with standard FD. Furthermore, the SENCEFUL technique hints at a potential clinical relevance by successfully detecting a perfusion defect in the patient scan. It can be concluded that SENCEFUL enables highly resolved ventilation- and perfusion-weighted maps of the human lung to be obtained using proton MRI, and might be interesting for further clinical evaluation.

Exciting multiple slices at the same time, ''controlled aliasing in parallel imaging results in higher acceleration'' (CAIPIRI-NHA) and ''phase-offset multiplanar'' have shown to be very effective techniques in 2D multislice imaging. Being provided with individual rf phase cycles, the simultaneously excited slices are shifted with respect to each other in the FOV and, thus, can be easily separated. For SSFP sequences, however, similar rf phase cycles are required to maintain the steady state, impeding a straightforward application of phase-offset multiplanar or controlled aliasing in parallel imaging results in higher acceleration. In this work, a new flexible concept for applying the two multislice imaging techniques to SSFP sequences is presented. Linear rf phase cycles are introduced providing both in one, the required shift between the slices and steady state in each slice throughout the whole measurement. Consequently, the concept is also appropriate for realtime and magnetization prepared imaging. Steady state properties and shifted banding behavior of the new phase cycles were investigated using simulations and phantom experiments. Moreover, the concept was applied to perform whole heart myocardial perfusion SSFP imaging as well as real-time and cine SSFP imaging with increased coverage. Showing no significant penalties in SNR or image quality, the results successfully demonstrate the general applicability of the concept. Magn Reson Med 65:157-164,