Compressed sensing for chemical shift‐based water–fat separation

Multi echo chemical shift‐based water–fat separation methods allow for uniform fat suppression in the presence of main field inhomogeneities. However, these methods require additional scan time for chemical shift encoding. This work presents a method for water–fat separation from undersampled data (CS‐WF), which combines compressed sensing and chemical shift‐based water–fat separation. Undersampling was applied in the k‐space and in the chemical shift encoding dimension to reduce the total scanning time. The method can reconstruct high quality water and fat images in 2D and 3D applications from undersampled data. As an extension, multipeak fat spectral models were incorporated into the CS‐WF reconstruction to improve the water–fat separation quality. In 3D MRI, reduction factors of above three can be achieved, thus fully compensating the additional time needed in three‐echo water–fat imaging. The method is demonstrated on knee and abdominal in vivo data. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.     

Fat/water separation using a concentric rings trajectory

The concentric rings two‐dimensional (2D) k‐space trajectory enables flexible trade‐offs between image contrast, signal‐to‐noise ratio (SNR), spatial resolution, and scan time. However, to realize these benefits for in vivo imaging applications, a robust method is desired to deal with fat signal in the acquired data. Multipoint Dixon techniques have been shown to achieve uniform fat suppression with high SNR‐efficiency for Cartesian imaging, but application of these methods for non‐Cartesian imaging is complicated by the fact that fat off‐resonance creates significant blurring artifacts in the reconstruction. In this work, two fat–water separation algorithms are developed for the concentric rings. A retracing design is used to sample rings near the center of k‐space through multiple revolutions to characterize the fat–water phase evolution difference at multiple time points. This acquisition design is first used for multipoint Dixon reconstruction, and then extended to a spectroscopic approach to account for the trajectory's full evolution through 3D k‐t space. As the trajectory is resolved in time, off‐resonance effects cause shifts in frequency instead of spatial blurring in 2D k‐space. The spectral information can be used to assess field variation and perform robust fat–water separation. In vivo experimental results demonstrate the effectiveness of both algorithms. Magn Reson Med, 2009. © 2008 Wiley‐Liss, Inc.     

Rapid water and lipid imaging with T2 mapping using a radial IDEAL‐GRASE technique

Three‐point Dixon methods have been investigated as a means to generate water and fat images without the effects of field inhomogeneities. Recently, an iterative algorithm (IDEAL, iterative decomposition of water and fat with echo asymmetry and least squares estimation) was combined with a gradient and spin‐echo acquisition strategy (IDEAL‐GRASE) to provide a time‐efficient method for lipid–water imaging with correction for the effects of field inhomogeneities. The method presented in this work combines IDEAL‐GRASE with radial data acquisition. Radial data sampling offers robustness to motion over Cartesian trajectories as well as the possibility of generating high‐resolution T₂ maps in addition to the water and fat images. The radial IDEAL‐GRASE technique is demonstrated in phantoms and in vivo for various applications including abdominal, pelvic, and cardiac imaging. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.     

Chemical shift encoding‐based water–fat separation methods

The suppression of signal from fat constitutes a basic requirement in many applications of magnetic resonance imaging. To date, this is predominantly achieved during data acquisition, using fat saturation, inversion recovery, or water excitation methods. Postponing the separation of signal from water and fat until image reconstruction holds the promise of resolving some of the problems associated with these methods, such as failure in the presence of field inhomogeneities or contrast agents. In this article, methods are reviewed that rely on the difference in chemical shift between the hydrogen atoms in water and fat to perform such a retrospective separation. The basic principle underlying these so‐called Dixon methods is introduced, and some fundamental implementations of the required chemical shift encoding in the acquisition and the subsequent water–fat separation in the reconstruction are described. Practical issues, such as the selection of key parameters and the appearance of typical artifacts, are illustrated, and a broad range of applications is demonstrated, including abdominal, cardiovascular, and musculoskeletal imaging. Finally, advantages and disadvantages of these Dixon methods are summarized, and emerging opportunities arising from the availability of information on the amount and distribution of fat are discussed. J. Magn. Reson. Imaging 2014;40:251–268 . © 2014 Wiley Periodicals, Inc .     

Accelerated water–fat imaging using restricted subspace field map estimation and compressed sensing

Water–fat separation techniques play an important role in a variety of clinical and research applications. In particular, multiecho separation methods remain a topic of great interest due to their ability to resolve water and fat images in the presence of B₀‐field inhomogeneity. However, these methods are inherently slow as they require multiple measurements. An accelerated technique with reduced k‐space sampling is desirable to decrease the scan time. This work presents a new method for water–fat separation from accelerated multiecho acquisitions. The proposed approach does not require the region‐growing or region‐merging schemes that are typically used for field map estimation. Instead, the water, fat, and field map signals are estimated directly from the undersampled k‐space measurements. In this work, up to 2.5×‐acceleration is demonstrated in a water–fat phantom, ankle, knee, and liver. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.     

Compressed sensing reconstruction for whole‐heart imaging with 3D radial trajectories: A graphics processing unit implementation

A disadvantage of three‐dimensional (3D) isotropic acquisition in whole‐heart coronary MRI is the prolonged data acquisition time. Isotropic 3D radial trajectories allow undersampling of k‐space data in all three spatial dimensions, enabling accelerated acquisition of the volumetric data. Compressed sensing (CS) reconstruction can provide further acceleration in the acquisition by removing the incoherent artifacts due to undersampling and improving the image quality. However, the heavy computational overhead of the CS reconstruction has been a limiting factor for its application. In this article, a parallelized implementation of an iterative CS reconstruction method for 3D radial acquisitions using a commercial graphics processing unit is presented. The execution time of the graphics processing unit‐implemented CS reconstruction was compared with that of the C++ implementation, and the efficacy of the undersampled 3D radial acquisition with CS reconstruction was investigated in both phantom and whole‐heart coronary data sets. Subsequently, the efficacy of CS in suppressing streaking artifacts in 3D whole‐heart coronary MRI with 3D radial imaging and its convergence properties were studied. The CS reconstruction provides improved image quality (in terms of vessel sharpness and suppression of noise‐like artifacts) compared with the conventional 3D gridding algorithm, and the graphics processing unit implementation greatly reduces the execution time of CS reconstruction yielding 34–54 times speed‐up compared with C++ implementation. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

T1‐weighted 3D dynamic contrast‐enhanced MRI of the breast using a dual‐echo dixon technique at 3 T

Purpose:

To evaluate a single‐pass fast spoiled gradient echo (FSPGR) two‐point Dixon sequence and a gradient echo sequence with spectral fat suppression in their performance at 3 T for fat suppressed contrast‐enhanced bilateral breast imaging.

Materials and Methods:

Twenty patients were prospectively enrolled in an imaging protocol that included axial Dixon and 3D FSPGR with spectrally selective fat saturation sequences as part of patient care in this study. Qualitative analysis was performed retrospectively by two readers who scored the images for homogeneity and degree of fat saturation, severity of artifacts, and quality of normal anatomical structures. Enhancing lesions were scored according to the confidence with which American College of Radiology (ACR) BI‐RADS magnetic resonance imaging (MRI) features were identified.

Results:

The Dixon sequence showed superior fat saturation homogeneity, quality of posterior anatomical structures, and decreased artifact severity that were statistically significant (P < 0.0001). The degree of fat saturation was scored higher in the Dixon sequence, although the difference did not reach statistical significance. There were no significant differences between the 3D T1‐weighted FSPGR and Dixon groups for assessing lesion features.

Conclusion:

Our findings suggest that the Dixon technique is an effective fat suppression method for contrast‐enhanced breast MRI. The Dixon technique also seemed to provide better anatomical definition of posterior structures and improvement in severity of artifacts. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.     

Chemical shift encoded water–fat separation using parallel imaging and compressed sensing

Chemical shift encoded techniques have received considerable attention recently because they can reliably separate water and fat in the presence of off‐resonance. The insensitivity to off‐resonance requires that data be acquired at multiple echo times, which increases the scan time as compared to a single echo acquisition. The increased scan time often requires that a compromise be made between the spatial resolution, the volume coverage, and the tolerance to artifacts from subject motion. This work describes a combined parallel imaging and compressed sensing approach for accelerated water–fat separation. In addition, the use of multiscale cubic B‐splines for B₀ field map estimation is introduced. The water and fat images and the B₀ field map are estimated via an alternating minimization. Coil sensitivity information is derived from a calculated k‐space convolution kernel and l₁‐regularization is imposed on the coil‐combined water and fat image estimates. Uniform water–fat separation is demonstrated from retrospectively undersampled data in the liver, brachial plexus, ankle, and knee as well as from a prospectively undersampled acquisition of the knee at 8.6x acceleration. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.     

Iterative decomposition of water and fat with echo asymmetry and least‐squares estimation (IDEAL): Application with fast spin‐echo imaging

Chemical shift based methods are often used to achieve uniform water–fat separation that is insensitive to B_o inhomogeneities. Many spin‐echo (SE) or fast SE (FSE) approaches acquire three echoes shifted symmetrically about the SE, creating time‐dependent phase shifts caused by water–fat chemical shift. This work demonstrates that symmetrically acquired echoes cause artifacts that degrade image quality. According to theory, the noise performance of any water–fat separation method is dependent on the proportion of water and fat within a voxel, and the position of echoes relative to the SE. To address this problem, we propose a method termed “iterative decomposition of water and fat with echo asymmetric and least‐squares estimation” (IDEAL). This technique combines asymmetrically acquired echoes with an iterative least‐squares decomposition algorithm to maximize noise performance. Theoretical calculations predict that the optimal echo combination occurs when the relative phase of the echoes is separated by 2π/3, with the middle echo centered at π/2+πk (k = any integer), i.e., (–π/6+πk, π/2+πk, 7π/6+πk). Only with these echo combinations can noise performance reach the maximum possible and be independent of the proportion of water and fat. Close agreement between theoretical and experimental results obtained from an oil–water phantom was observed, demonstrating that the iterative least‐squares decomposition method is an efficient estimator. Magn Reson Med, 2005. © 2005 Wiley‐Liss, Inc.     

Combination of complex‐based and magnitude‐based multiecho water‐fat separation for accurate quantification of fat‐fraction

Multipoint water–fat separation techniques rely on different water–fat phase shifts generated at multiple echo times to decompose water and fat. Therefore, these methods require complex source images and allow unambiguous separation of water and fat signals. However, complex‐based water–fat separation methods are sensitive to phase errors in the source images, which may lead to clinically important errors. An alternative approach to quantify fat is through “magnitude‐based” methods that acquire multiecho magnitude images. Magnitude‐based methods are insensitive to phase errors, but cannot estimate fat‐fraction greater than 50%. In this work, we introduce a water–fat separation approach that combines the strengths of both complex and magnitude reconstruction algorithms. A magnitude‐based reconstruction is applied after complex‐based water–fat separation to removes the effect of phase errors. The results from the two reconstructions are then combined. We demonstrate that using this hybrid method, 0–100% fat‐fraction can be estimated with improved accuracy at low fat‐fractions. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

A new approach to autocalibrated dynamic parallel imaging based on the Karhunen‐Loeve transform: KL‐TSENSE and KL‐TGRAPPA

TSENSE and TGRAPPA are autocalibrated parallel imaging techniques that can improve the temporal resolution and/or spatial resolution in dynamic magnetic resonance imaging applications. In its original form, TSENSE uses temporal low‐pass filtering of the undersampled frames to create the sensitivity map. TGRAPPA uses a sliding‐window moving average when finding the autocalibrating signals. Both filtering methods are suboptimal in the least‐squares sense and may give rise to mismatches between the undersampled k‐space raw data and the corresponding coil sensitivities. Such mismatches may result in aliasing artifacts when imaging patients with heavy breathing, as in real‐time imaging of wall motion by MRI following a treadmill exercise stress test. In this study, we demonstrate the use of an optimal linear filter, i.e., the Karhunen‐Loeve transform filter, to estimate the channel sensitivity for TSENSE and acquire the autocalibration signals for TGRAPPA. Phantom experiments show that the new reconstruction method has comparable signal‐to‐noise ratio performance to traditional TSENSE/TGRAPPA reconstruction. In vivo real‐time cardiac cine experiments performed in five healthy volunteers post‐exercise during rapid respiration show that the new method significantly reduces the chest wall aliasing artifacts caused by respiratory motion (P < 0.001). Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Generalized GRAPPA operators for wider spiral bands: Rapid self‐calibrated parallel reconstruction for variable density spiral MRI

A rapid and self‐calibrated parallel imaging reconstruction method is proposed for undersampled variable density spiral datasets. A set of generalized GRAPPA for wider readout line operators are used to expand each acquired spiral line into a wider spiral band, therefore fulfilling Nyquist sampling criterion throughout the k‐space. The calibration of generalized GRAPPA for wider readout line operators is performed using the fully sampled central k‐space region. The resulting generalized GRAPPA for wider readout line operator weights are adaptively regularized to minimize the error in the newly‐generated data at different k‐space locations. Simulation and experimental results demonstrate that the technique can be used either to achieve a significant acceleration and/or to reduce off‐resonance artifacts due to a shorten readout duration. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

DCE-MRI of the human kidney using BLADE: a feasibility study in healthy volunteers

Purpose:

To evaluate the degree of motion compensation in the kidney using two different sampling methods, each in their optimized settings: A BLADE k‐space acquisition technique and a routinely used kidney perfusion acquisition scheme (TurboFLASH).

Materials and Methods:

Dynamic contrast enhanced magnetic resonance examinations were performed in 16 healthy volunteers on a 3 Tesla MR‐system with two parameterizations of the BLADE sequence and the standard reference acquisition scheme. Signal intensity enhanced time curves were analyzed with a mathematical model and a widely published separable compartment model on cortex regions to assess robustness versus motion artifacts.

Results:

BLADE‐measurements with a strip‐width of 32 lines constituted the smallest mean values for the sum of squared errors (6065 ± 4996) compared with the measurement with a strip‐width of 64 lines (13849 ± 14079) or the standard TurboFLASH (11884 ± 8076). Calculations concerning goodness of the fit of the applied compartment model yielded an overall average of the Akaike Fit Error of 732 ± 141 for BLADE (646 ± 149 for a strip‐width of 32 lines, 816 ± 53 for 64 lines) and 1626 ± 303 for the TurboFLASH (TFL) sequence.

Conclusion:

We demonstrated that renal dynamic contrast enhanced magnetic resonance imaging using BLADE k‐space sampling with a strip‐width of 32 is significantly less sensitive to motion than a widely published Turbo‐Flash sequence with nearly similar parameters. J. Magn. Reson. Imaging 2012;35:868–874. © 2011 Wiley Periodicals, Inc.     

Novel application of T1‐weighted BLADE sequences with fat suppression compared to TSE in contrast‐enhanced T1‐weighted imaging of the neck: Cutting‐edge images?

Purpose:

To evaluate if the use of BLADE sequences might overcome some limitations of magnetic resonance imaging (MRI) in the extracranial head and neck, which is a diagnostically challenging area with a variety of artifacts and a broad spectrum of potential lesions.

Materials and Methods:

After informed consent and Institutional Review Board approval, two different BLADE sequences with (BLADE IR) and without inversion pulse (BLADE) were compared to turbo‐spin echo (TSE) with fat saturation for coronal T1‐weighted postcontrast imaging of the extracranial head and neck region in 40 individuals of a routine patient collective. Visual evaluation of image sharpness, motion artifacts, vessel pulsation, contrast of anatomic structures, contrast of pathologies to surrounding tissue as well as BLADE‐specific artifacts was performed by two experienced, independent readers. Statistical evaluation was done by using the Wilcoxon test.

Results:

Both BLADE and BLADE IR were significantly superior to TSE regarding pulsation artifacts and delineation of thoracic structures. TSE provided better results concerning contrast muscle/fat tissue and contrast lymph nodes/fat. More important, it showed significantly better contrast of several lesions, facilitating the detection of patient pathology.

Conclusion:

T1‐weighted coronal imaging of the extracranial head and neck region is demanding. T1‐weighted BLADE sequences still have drawbacks in anatomical contrast and lesion detection but offer possibilities to achieve reasonable image quality in difficult cases with a variety of artifacts. J. Magn. Reson. Imaging 2013;37:660—668. © 2012 Wiley Periodicals, Inc.     

Fast spin-echo triple echo dixon: Initial clinical experience with a novel pulse sequence for simultaneous fat-suppressed and nonfat-suppressed T2-weighted spine magnetic resonance imaging

Purpose

To evaluate a prototype fast spin‐echo (FSE) triple‐echo Dixon (FTED) technique for T2‐weighted spine imaging with and without fat suppression compared to conventional T2‐weighted fast recovery (FR) FSE and short‐tau inversion recovery (STIR) imaging.

Materials and Methods

Sixty‐one patients were referred for spine magnetic resonance imaging (MRI) including sagittal FTED (time 2:26), STIR (time 2:42), and T2 FRFSE (time 2:55). Two observers compared STIR and FTED water images and T2 FRFSE and FTED T2 images for overall image quality, fat suppression, anatomic sharpness, motion, cerebrospinal fluid (CSF) flow artifact, susceptibility, and disease depiction.

Results

On FTED images water and fat separation was perfect in 58 (.95) patients. Compared to STIR, the FTED water images demonstrated less motion in 57 (.93) of 61 patients (P < 0.05), better anatomic sharpness in 51 (.84) and patients (P < 0.05), and less CSF flow artifact in 7 (.11) P < 0.05) patients. There was no difference in fat suppression or chemical shift artifact. T2 FRFSE and FTED T2 images showed equivalent motion, CSF flow, and chemical shift artifact. Lesion depiction was equivalent on FTED water and STIR images and FTED T2 and T2 FRFSE images.

Conclusion

FTED efficiently provides both fat‐suppressed and nonfat‐suppressed T2‐weighted spine images with excellent image quality, equal disease depiction, and 56% reduction in scan time compared to conventional STIR and T2 FRFSE. J. Magn. Reson. Imaging 2011;33:390–400. © 2011 Wiley‐Liss, Inc.     

Development and evaluation of TWIST Dixon for dynamic contrast-enhanced (DCE) MRI with improved acquisition efficiency and fat suppression

Purpose:

To develop a new pulse sequence called time‐resolved angiography with stochastic trajectories (TWIST) Dixon for dynamic contrast enhanced magnetic resonance imaging (DCE‐MRI).

Materials and Methods:

The method combines dual‐echo Dixon to generate separated water and fat images with a k‐space view‐sharing scheme developed for 3D TWIST. The performance of TWIST Dixon was compared with a volume interpolated breathhold examination (VIBE) sequence paired with spectrally selective adiabatic inversion Recovery (SPAIR) and quick fat‐sat (QFS) fat‐suppression techniques at 3.0T using quantitative measurements of fat‐suppression accuracy and signal‐to‐noise ratio (SNR) efficiency, as well as qualitative breast image evaluations.

Results:

The water fraction of a uniform phantom was calculated from the following images: 0.66 ± 0.03 for TWIST Dixon; 0.56 ± 0.23 for VIBE‐SPAIR, and 0.53 ± 0.14 for VIBE‐QFS, while the reference value is 0.70 measured by spectroscopy. For phantoms with contrast (Gd‐BOPTA) concentration ranging from 0–6 mM, TWIST Dixon also provides consistently higher SNR efficiency (3.2–18.9) compared with VIBE‐SPAIR (2.8–16.8) and VIBE‐QFS (2.4–12.5). Breast images acquired with TWIST Dixon at 3.0T show more robust and uniform fat suppression and superior overall image quality compared with VIBE‐SPAIR.

Conclusion:

The results from phantom and volunteer evaluation suggest that TWIST Dixon outperforms conventional methods in almost every aspect and it is a promising method for DCE‐MRI and contrast‐enhanced perfusion MRI, especially at higher field strength where fat suppression is challenging. J. Magn. Reson. Imaging 2012;36:483–491. © 2012 Wiley Periodicals, Inc.     

Three‐point dixon method enables whole‐body water and fat imaging of obese subjects

Dixon imaging techniques derive chemical shift‐separated water and fat images, enabling the quantification of fat content and forming an alternative to fat suppression. Whole‐body Dixon imaging is of interest in studies of obesity and the metabolic syndrome, and possibly in oncology. A three‐point Dixon method is proposed where two solutions are found analytically in each voxel. The true solution is identified by a multiseed three‐dimensional region‐growing scheme with a dynamic path, allowing confident regions to be solved before unconfident regions, such as background noise. 2π‐Phase unwrapping is not required. Whole‐body datasets (256 × 184 × 252 voxels) were collected from 39 subjects (body mass index 19.8‐45.4 kg/m²), in a mean scan time of 5 min 15 sec. Water and fat images were reconstructed offline, using the proposed method and two reference methods. The resulting images were subjectively graded on a four‐grade scale by two radiologists, blinded to the method used. The proposed method was found superior to the reference methods. It exclusively received the two highest grades, implying that only mild reconstruction failures were found. The computation time for a whole‐body dataset was 1 min 51.5 sec ± 3.0 sec. It was concluded that whole‐body water and fat imaging is feasible even for obese subjects, using the proposed method. Magn Reson Med 63:1659–1668, 2010. © 2010 Wiley‐Liss, Inc.     

DIfferential Subsampling with Cartesian Ordering (DISCO): a high spatio-temporal resolution Dixon imaging sequence for multiphasic contrast enhanced abdominal imaging

Purpose:

To develop and evaluate a multiphasic contrast‐enhanced MRI method called DIfferential Sub‐sampling with Cartesian Ordering (DISCO) for abdominal imaging.

Materials and Methods:

A three‐dimensional, variable density pseudo‐random k‐space segmentation scheme was developed and combined with a Dixon‐based fat‐water separation algorithm to generate high temporal resolution images with robust fat suppression and without compromise in spatial resolution or coverage. With institutional review board approval and informed consent, 11 consecutive patients referred for abdominal MRI at 3 Tesla (T) were imaged with both DISCO and a routine clinical three‐dimensional SPGR‐Dixon (LAVA FLEX) sequence. All images were graded by two radiologists using quality of fat suppression, severity of artifacts, and overall image quality as scoring criteria. For assessment of arterial phase capture efficiency, the number of temporal phases with angiographic phase and hepatic arterial phase was recorded.

Results:

There were no significant differences in quality of fat suppression, artifact severity or overall image quality between DISCO and LAVA FLEX images (P > 0.05, Wilcoxon signed rank test). The angiographic and arterial phases were captured in all 11 patients scanned using the DISCO acquisition (mean number of phases were two and three, respectively).

Conclusion:

DISCO effectively captures the fast dynamics of abdominal pathology such as hyperenhancing hepatic lesions with a high spatio‐temporal resolution. Typically, 1.1 × 1.5 × 3 mm spatial resolution over 60 slices was achieved with a temporal resolution of 4–5 s. J. Magn. Reson. Imaging 2012;35:1484–1492. © 2012 Wiley Periodicals, Inc.     

High‐resolution 3D radial bSSFP with IDEAL

Radial trajectories facilitate high‐resolution balanced steady state free precession (bSSFP) because the efficient gradients provide more time to extend the trajectory in k‐space. A number of radial bSSFP methods that support fat–water separation have been developed; however, most of these methods require an environment with limited B₀ inhomogeneity. In this work, high‐resolution bSSFP with fat–water separation is achieved in more challenging B₀ environments by combining a 3D radial trajectory with the IDEAL chemical species separation method. A method to maintain very high resolution within the timing constraints of bSSFP and IDEAL is described using a dual‐pass pulse sequence. The sampling of a unique set of radial lines at each echo time is investigated as a means to circumvent the longer scan time that IDEAL incurs as a multiecho acquisition. The manifestation of undersampling artifacts in this trajectory and their effect on chemical species separation are investigated in comparison to the case in which each echo samples the same set of radial lines. This new bSSFP method achieves 0.63 mm isotropic resolution in a 5‐min scan and is demonstrated in difficult in vivo imaging environments, including the breast and a knee with ACL reconstruction hardware at 1.5 T. Magn Reson Med 71:95–104, 2014. © 2013 Wiley Periodicals, Inc.     

Fat‐water separated delayed hyperenhanced myocardial infarct imaging

Fat deposition associated with myocardial infarction (MI) has been reported as a commonly occurring phenomenon. Magnetic resonance imaging (MRI) has the ability to efficiently detect MI using T₁‐sensitive contrast‐enhanced sequences and fat via its resonant frequency shift. In this work, the feasibility of fat‐water separation applied to the conventional delayed hyperenhanced (DHE) MI imaging technique is demonstrated. A three‐point Dixon acquisition and reconstruction was combined with an inversion recovery gradient‐echo pulse sequence. This allowed fat‐water separation along with T₁ sensitive imaging after injection of a gadolinium contrast agent. The technique is demonstrated in phantom experiments and three subjects with chronic MI. Areas of infarction were well defined as conventional hyperenhancement in water images. In two cases, fatty deposition was detected in fat images and confirmed by precontrast opposed‐phase imaging. Magn Reson Med 60:503–509, 2008. © 2008 Wiley‐Liss, Inc.