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Regional Myocardial Function: Advances in MR Imaging and Analysis¹

¹ From the Russell H. Morgan Department of Radiology and Radiological Sciences (E.C., D.A.B.), and the Department of Medicine, Division of Cardiology (J.A.C.L.), Johns Hopkins University School of Medicine, MRI-143 Nelson Basement, 600 N Wolfe St, Baltimore, MD 21287-0845. Presented as an education exhibit at the 2002 RSNA scientific assembly. Received February 26, 2003; revision requested April 28 and received May 16; accepted May 20. E.C. supported by a research grant from the Fundación Ramón Areces, Madrid, Spain. Address correspondence to E.C. (e-mail: ecastillo@jhmi.edu).

View larger version (138K): [in a new window]   Figure 1a.  Long-axis cine MR images obtained with a fast GRE sequence (repetition time msec/echo time msec = 8.1/4.5, angle of 20°) (a, b) and an SSFP sequence (3.7/1.5, angle of 45°) (c, d) in a 68-year-old man with coronary artery disease. The heterogeneous blood-pool signal intensity seen in the GRE images, which was caused by slow blood flow, is not present in the SSFP images.

View larger version (137K): [in a new window]   Figure 1b.  Long-axis cine MR images obtained with a fast GRE sequence (repetition time msec/echo time msec = 8.1/4.5, angle of 20°) (a, b) and an SSFP sequence (3.7/1.5, angle of 45°) (c, d) in a 68-year-old man with coronary artery disease. The heterogeneous blood-pool signal intensity seen in the GRE images, which was caused by slow blood flow, is not present in the SSFP images.

View larger version (153K): [in a new window]   Figure 1c.  Long-axis cine MR images obtained with a fast GRE sequence (repetition time msec/echo time msec = 8.1/4.5, angle of 20°) (a, b) and an SSFP sequence (3.7/1.5, angle of 45°) (c, d) in a 68-year-old man with coronary artery disease. The heterogeneous blood-pool signal intensity seen in the GRE images, which was caused by slow blood flow, is not present in the SSFP images.

View larger version (148K): [in a new window]   Figure 1d.  Long-axis cine MR images obtained with a fast GRE sequence (repetition time msec/echo time msec = 8.1/4.5, angle of 20°) (a, b) and an SSFP sequence (3.7/1.5, angle of 45°) (c, d) in a 68-year-old man with coronary artery disease. The heterogeneous blood-pool signal intensity seen in the GRE images, which was caused by slow blood flow, is not present in the SSFP images.

View larger version (153K): [in a new window]   Figure 2a.  Wall thickening analysis of short-axis cine MR images obtained in a 71-year-old man with chronic myocardial infarction in the region of the left anterior descending artery. (a) Delayed-enhancement short-axis image obtained with gadolinium-based contrast material shows transmural hyperenhancement (arrows) in the thinned myocardial wall of the septum and in the anterior wall corresponding to scar tissue. (b) The endocardial and epicardial contours are diagrammed on the SSFP image. Chords for measuring wall thickness are shown along the left ventricular circumference. (c) Bull's-eye plot shows the extent of wall thickening. The smallest ring represents the apical region, and the largest ring represents the basal region. There is reduced thickening (from 0%-30%) in the scar tissue and surrounding myocardium (arrowheads) compared with thickening of more than 200% in the remote myocardium (arrows).

View larger version (133K): [in a new window]   Figure 2b.  Wall thickening analysis of short-axis cine MR images obtained in a 71-year-old man with chronic myocardial infarction in the region of the left anterior descending artery. (a) Delayed-enhancement short-axis image obtained with gadolinium-based contrast material shows transmural hyperenhancement (arrows) in the thinned myocardial wall of the septum and in the anterior wall corresponding to scar tissue. (b) The endocardial and epicardial contours are diagrammed on the SSFP image. Chords for measuring wall thickness are shown along the left ventricular circumference. (c) Bull's-eye plot shows the extent of wall thickening. The smallest ring represents the apical region, and the largest ring represents the basal region. There is reduced thickening (from 0%-30%) in the scar tissue and surrounding myocardium (arrowheads) compared with thickening of more than 200% in the remote myocardium (arrows).

View larger version (94K): [in a new window]   Figure 2c.  Wall thickening analysis of short-axis cine MR images obtained in a 71-year-old man with chronic myocardial infarction in the region of the left anterior descending artery. (a) Delayed-enhancement short-axis image obtained with gadolinium-based contrast material shows transmural hyperenhancement (arrows) in the thinned myocardial wall of the septum and in the anterior wall corresponding to scar tissue. (b) The endocardial and epicardial contours are diagrammed on the SSFP image. Chords for measuring wall thickness are shown along the left ventricular circumference. (c) Bull's-eye plot shows the extent of wall thickening. The smallest ring represents the apical region, and the largest ring represents the basal region. There is reduced thickening (from 0%-30%) in the scar tissue and surrounding myocardium (arrowheads) compared with thickening of more than 200% in the remote myocardium (arrows).

View larger version (39K): [in a new window]   Figure 3.  Scheme of coordinate systems for measuring myocardial strain defined by the finite strain tensor E. Normal strains (black arrows) are defined in relation to the circumferential, or short-axis, plane: Circumferential shortening (Ecc) occurs parallel to the tangent of the myocardium with respect to the epicardial surface (shown here as the endocardial surface for space reasons); radial thickening (ERR) occurs perpendicular to the circumferential direction, toward the ventricular centroid; and longitudinal shortening (ELL) occurs perpendicular to the other two components and parallel to the longitudinal axis of the left ventricle. Principal strains (white arrows) are defined in relation to the direction of movement in the main myocyte fiber bundles during systolic deformation. The maximal principal strain is the greatest elongation (E1) orthogonal to the fiber direction. The minimal principal strain is the greatest shortening (E2) parallel to the fiber direction. Principal strains are referred to the major and minor axes of an ellipse resulting from the deformation of a circle during systole because of wall shear. Strain that occurs perpendicular to these two principal strains is labeled E3. The angles between Ecc-E2 and ERR-E1 are defined as and ß, respectively.

View larger version (172K): [in a new window]   Figure 4a.  Early-systolic (a, d), end-systolic (b, e), and end-diastolic (c, f) short-axis tagged MR images were obtained by using CSPAMM with spiral readout. Spiral readout is a very efficient k-space sampling method that allows high temporal resolution (a-c) or high isotropic spatial resolution (d-f). The high-temporal-resolution images were acquired with 12 interleaved spiral readouts in 13 msec (45 heart phases) at a tag spacing of 8 mm. The high-spatial-resolution images (1.5 x 1.5 mm) have a tag spacing of 4 mm and a temporal resolution of 35 msec (16 heart phases). (Courtesy of S. Ryf, MSc, ETH Zürich, and M. Stuber, PhD, Johns Hopkins University, Baltimore, Md.)

View larger version (166K): [in a new window]   Figure 4b.  Early-systolic (a, d), end-systolic (b, e), and end-diastolic (c, f) short-axis tagged MR images were obtained by using CSPAMM with spiral readout. Spiral readout is a very efficient k-space sampling method that allows high temporal resolution (a-c) or high isotropic spatial resolution (d-f). The high-temporal-resolution images were acquired with 12 interleaved spiral readouts in 13 msec (45 heart phases) at a tag spacing of 8 mm. The high-spatial-resolution images (1.5 x 1.5 mm) have a tag spacing of 4 mm and a temporal resolution of 35 msec (16 heart phases). (Courtesy of S. Ryf, MSc, ETH Zürich, and M. Stuber, PhD, Johns Hopkins University, Baltimore, Md.)

View larger version (159K): [in a new window]   Figure 4c.  Early-systolic (a, d), end-systolic (b, e), and end-diastolic (c, f) short-axis tagged MR images were obtained by using CSPAMM with spiral readout. Spiral readout is a very efficient k-space sampling method that allows high temporal resolution (a-c) or high isotropic spatial resolution (d-f). The high-temporal-resolution images were acquired with 12 interleaved spiral readouts in 13 msec (45 heart phases) at a tag spacing of 8 mm. The high-spatial-resolution images (1.5 x 1.5 mm) have a tag spacing of 4 mm and a temporal resolution of 35 msec (16 heart phases). (Courtesy of S. Ryf, MSc, ETH Zürich, and M. Stuber, PhD, Johns Hopkins University, Baltimore, Md.)

View larger version (186K): [in a new window]   Figure 4d.  Early-systolic (a, d), end-systolic (b, e), and end-diastolic (c, f) short-axis tagged MR images were obtained by using CSPAMM with spiral readout. Spiral readout is a very efficient k-space sampling method that allows high temporal resolution (a-c) or high isotropic spatial resolution (d-f). The high-temporal-resolution images were acquired with 12 interleaved spiral readouts in 13 msec (45 heart phases) at a tag spacing of 8 mm. The high-spatial-resolution images (1.5 x 1.5 mm) have a tag spacing of 4 mm and a temporal resolution of 35 msec (16 heart phases). (Courtesy of S. Ryf, MSc, ETH Zürich, and M. Stuber, PhD, Johns Hopkins University, Baltimore, Md.)

View larger version (181K): [in a new window]   Figure 4e.  Early-systolic (a, d), end-systolic (b, e), and end-diastolic (c, f) short-axis tagged MR images were obtained by using CSPAMM with spiral readout. Spiral readout is a very efficient k-space sampling method that allows high temporal resolution (a-c) or high isotropic spatial resolution (d-f). The high-temporal-resolution images were acquired with 12 interleaved spiral readouts in 13 msec (45 heart phases) at a tag spacing of 8 mm. The high-spatial-resolution images (1.5 x 1.5 mm) have a tag spacing of 4 mm and a temporal resolution of 35 msec (16 heart phases). (Courtesy of S. Ryf, MSc, ETH Zürich, and M. Stuber, PhD, Johns Hopkins University, Baltimore, Md.)

View larger version (176K): [in a new window]   Figure 4f.  Early-systolic (a, d), end-systolic (b, e), and end-diastolic (c, f) short-axis tagged MR images were obtained by using CSPAMM with spiral readout. Spiral readout is a very efficient k-space sampling method that allows high temporal resolution (a-c) or high isotropic spatial resolution (d-f). The high-temporal-resolution images were acquired with 12 interleaved spiral readouts in 13 msec (45 heart phases) at a tag spacing of 8 mm. The high-spatial-resolution images (1.5 x 1.5 mm) have a tag spacing of 4 mm and a temporal resolution of 35 msec (16 heart phases). (Courtesy of S. Ryf, MSc, ETH Zürich, and M. Stuber, PhD, Johns Hopkins University, Baltimore, Md.)

View larger version (143K): [in a new window]   Figure 5a.  HARP image analysis. The HARP technique enables measurement of motion from a series of tagged MR images (such as that in a) by filtering selected peaks in the k-space representation of the image (circle in b). The resulting image can be decomposed into a harmonic magnitude image (c) or a HARP image (d). The magnitude image shows anatomic detail and can be used for segmentation. In contrast, the HARP image contains myocardial motion information. Because the value of a material point on a HARP image is invariant over time, this technique can be used to track the trajectory of a given point or points and to compute either lagrangian or eulerian measurements of strain.

View larger version (71K): [in a new window]   Figure 5b.  HARP image analysis. The HARP technique enables measurement of motion from a series of tagged MR images (such as that in a) by filtering selected peaks in the k-space representation of the image (circle in b). The resulting image can be decomposed into a harmonic magnitude image (c) or a HARP image (d). The magnitude image shows anatomic detail and can be used for segmentation. In contrast, the HARP image contains myocardial motion information. Because the value of a material point on a HARP image is invariant over time, this technique can be used to track the trajectory of a given point or points and to compute either lagrangian or eulerian measurements of strain.

View larger version (120K): [in a new window]   Figure 5c.  HARP image analysis. The HARP technique enables measurement of motion from a series of tagged MR images (such as that in a) by filtering selected peaks in the k-space representation of the image (circle in b). The resulting image can be decomposed into a harmonic magnitude image (c) or a HARP image (d). The magnitude image shows anatomic detail and can be used for segmentation. In contrast, the HARP image contains myocardial motion information. Because the value of a material point on a HARP image is invariant over time, this technique can be used to track the trajectory of a given point or points and to compute either lagrangian or eulerian measurements of strain.

View larger version (54K): [in a new window]   Figure 5d.  HARP image analysis. The HARP technique enables measurement of motion from a series of tagged MR images (such as that in a) by filtering selected peaks in the k-space representation of the image (circle in b). The resulting image can be decomposed into a harmonic magnitude image (c) or a HARP image (d). The magnitude image shows anatomic detail and can be used for segmentation. In contrast, the HARP image contains myocardial motion information. Because the value of a material point on a HARP image is invariant over time, this technique can be used to track the trajectory of a given point or points and to compute either lagrangian or eulerian measurements of strain.

View larger version (113K): [in a new window]   Figure 6a.  HARP analysis of short-axis tagged MR images. (a) A circular grid that contains a variable number of segments of equal size (in this case, 12) is defined by the user to represent the region of measurement within the left ventricular wall (green = subendocardial layer, red = midwall, blue = subepicardial layer). Points on the grid are then automatically tracked through all the image sections in the data set, and strain values are calculated from the trajectory of each point. (b) Calculated strain values are displayed as a color-coded map superimposed on the tagged images. (c) Strain plots show circumferential shortening in every segment and in all three layers (color coded as in a and b). The x axis represents the number of imaged phases of the cardiac cycle (20, up to a maximum of 670 msec), and the y axis is the percentage of change in circumferential shortening.

View larger version (86K): [in a new window]   Figure 6b.  HARP analysis of short-axis tagged MR images. (a) A circular grid that contains a variable number of segments of equal size (in this case, 12) is defined by the user to represent the region of measurement within the left ventricular wall (green = subendocardial layer, red = midwall, blue = subepicardial layer). Points on the grid are then automatically tracked through all the image sections in the data set, and strain values are calculated from the trajectory of each point. (b) Calculated strain values are displayed as a color-coded map superimposed on the tagged images. (c) Strain plots show circumferential shortening in every segment and in all three layers (color coded as in a and b). The x axis represents the number of imaged phases of the cardiac cycle (20, up to a maximum of 670 msec), and the y axis is the percentage of change in circumferential shortening.

View larger version (37K): [in a new window]   Figure 6c.  HARP analysis of short-axis tagged MR images. (a) A circular grid that contains a variable number of segments of equal size (in this case, 12) is defined by the user to represent the region of measurement within the left ventricular wall (green = subendocardial layer, red = midwall, blue = subepicardial layer). Points on the grid are then automatically tracked through all the image sections in the data set, and strain values are calculated from the trajectory of each point. (b) Calculated strain values are displayed as a color-coded map superimposed on the tagged images. (c) Strain plots show circumferential shortening in every segment and in all three layers (color coded as in a and b). The x axis represents the number of imaged phases of the cardiac cycle (20, up to a maximum of 670 msec), and the y axis is the percentage of change in circumferential shortening.

View larger version (138K): [in a new window]   Figure 7a.  Myocardial infarction in the left anterior descending coronary artery in a 40-year-old man. (a) Short-axis delayed-enhancement image shows extensive hyperenhancement in the anterior wall and septum, which corresponds to an extensive infarction. Nonenhanced subendocardial areas (arrows) correspond to microvascular obstruction after acute infarction. (b, c) Color-coded maps superimposed on tagged MR images acquired in early systole (b) and end systole (c) show the regional extent of circumferential shortening. Contraction, indicated in blue, is evident mainly in the remote myocardial areas (arrowheads). In the infarcted region, virtually no contraction is evident, as is indicated by green; a slight myocardial lengthening, indicated by red, is evident in the area of microvascular obstruction (arrows in c).

View larger version (118K): [in a new window]   Figure 7b.  Myocardial infarction in the left anterior descending coronary artery in a 40-year-old man. (a) Short-axis delayed-enhancement image shows extensive hyperenhancement in the anterior wall and septum, which corresponds to an extensive infarction. Nonenhanced subendocardial areas (arrows) correspond to microvascular obstruction after acute infarction. (b, c) Color-coded maps superimposed on tagged MR images acquired in early systole (b) and end systole (c) show the regional extent of circumferential shortening. Contraction, indicated in blue, is evident mainly in the remote myocardial areas (arrowheads). In the infarcted region, virtually no contraction is evident, as is indicated by green; a slight myocardial lengthening, indicated by red, is evident in the area of microvascular obstruction (arrows in c).

View larger version (98K): [in a new window]   Figure 7c.  Myocardial infarction in the left anterior descending coronary artery in a 40-year-old man. (a) Short-axis delayed-enhancement image shows extensive hyperenhancement in the anterior wall and septum, which corresponds to an extensive infarction. Nonenhanced subendocardial areas (arrows) correspond to microvascular obstruction after acute infarction. (b, c) Color-coded maps superimposed on tagged MR images acquired in early systole (b) and end systole (c) show the regional extent of circumferential shortening. Contraction, indicated in blue, is evident mainly in the remote myocardial areas (arrowheads). In the infarcted region, virtually no contraction is evident, as is indicated by green; a slight myocardial lengthening, indicated by red, is evident in the area of microvascular obstruction (arrows in c).

View larger version (98K): [in a new window]   Figure 8.  Depiction of myocardial ischemia with a real-time pulse sequence based on HARP imaging principles. Color map superimposed on short-axis, end-systolic, tagged cine MR images of acute ischemia in a canine model shows the extent of circumferential shortening. On the color scale, green indicates no change, blue indicates contraction (negative values), and red indicates stretching (positive values). On the first image, which was acquired at 1 second of imaging, before coronary artery occlusion, the strain values are uniform. On the second image, acquired about 10 seconds after coronary artery occlusion (ie, at 28 seconds of imaging), an area in the anterior wall near the left anterior descending coronary artery shows stretching secondary to ischemia (arrows). This area increases over time until 120 seconds of imaging, when deflation of the balloon catheter occurs. In the remote area of the opposite wall, shortening appears to have increased (arrowheads) compared with the baseline. After deflation (at 125-135 seconds), the ischemic region recovers and again shows contraction.

View larger version (109K): [in a new window]   Figure 9a.  Through-plane strain information obtained with strain-encoded MR imaging. (a-c) Longitudinal shortening is displayed on a composite short-axis image (a) obtained by combining an image with low tagging frequency (b) and an image with high tagging frequency (c). Dyskinetic tissue with stretching (1 in a) is represented by a hyperintense area on the low-frequency image and by a hypointense area on the high-frequency image. Akinetic myocardial tissue (2 in a), in which there is no contraction, has an appearance identical to that of surrounding static tissue (ie, chest wall or liver). Severely hypokinetic tissue (3 in a) and normally contracting subendocardial or midwall tissue (4 and 5 in a) show an inverse intensity pattern directly related to the strain values on a pixel-by-pixel basis. (d-f) Short-axis strain-encoded MR images obtained in a 68-year-old woman after myocardial infarction. The low-frequency image (d) shows subendocardial hyperintense areas (arrows) that indicate myocardial dysfunction; the same areas are represented in red on the composite color-coded image (e). Delayed-enhancement image (f) shows a subendocardial area of hyperenhancement (arrows) in the region of the left anterior descending artery that represents chronic myocardial infarction and that corresponds with the areas of dysfunction depicted on the strain-encoded images.

View larger version (46K): [in a new window]   Figure 9b.  Through-plane strain information obtained with strain-encoded MR imaging. (a-c) Longitudinal shortening is displayed on a composite short-axis image (a) obtained by combining an image with low tagging frequency (b) and an image with high tagging frequency (c). Dyskinetic tissue with stretching (1 in a) is represented by a hyperintense area on the low-frequency image and by a hypointense area on the high-frequency image. Akinetic myocardial tissue (2 in a), in which there is no contraction, has an appearance identical to that of surrounding static tissue (ie, chest wall or liver). Severely hypokinetic tissue (3 in a) and normally contracting subendocardial or midwall tissue (4 and 5 in a) show an inverse intensity pattern directly related to the strain values on a pixel-by-pixel basis. (d-f) Short-axis strain-encoded MR images obtained in a 68-year-old woman after myocardial infarction. The low-frequency image (d) shows subendocardial hyperintense areas (arrows) that indicate myocardial dysfunction; the same areas are represented in red on the composite color-coded image (e). Delayed-enhancement image (f) shows a subendocardial area of hyperenhancement (arrows) in the region of the left anterior descending artery that represents chronic myocardial infarction and that corresponds with the areas of dysfunction depicted on the strain-encoded images.

View larger version (43K): [in a new window]   Figure 9c.  Through-plane strain information obtained with strain-encoded MR imaging. (a-c) Longitudinal shortening is displayed on a composite short-axis image (a) obtained by combining an image with low tagging frequency (b) and an image with high tagging frequency (c). Dyskinetic tissue with stretching (1 in a) is represented by a hyperintense area on the low-frequency image and by a hypointense area on the high-frequency image. Akinetic myocardial tissue (2 in a), in which there is no contraction, has an appearance identical to that of surrounding static tissue (ie, chest wall or liver). Severely hypokinetic tissue (3 in a) and normally contracting subendocardial or midwall tissue (4 and 5 in a) show an inverse intensity pattern directly related to the strain values on a pixel-by-pixel basis. (d-f) Short-axis strain-encoded MR images obtained in a 68-year-old woman after myocardial infarction. The low-frequency image (d) shows subendocardial hyperintense areas (arrows) that indicate myocardial dysfunction; the same areas are represented in red on the composite color-coded image (e). Delayed-enhancement image (f) shows a subendocardial area of hyperenhancement (arrows) in the region of the left anterior descending artery that represents chronic myocardial infarction and that corresponds with the areas of dysfunction depicted on the strain-encoded images.

View larger version (148K): [in a new window]   Figure 9d.  Through-plane strain information obtained with strain-encoded MR imaging. (a-c) Longitudinal shortening is displayed on a composite short-axis image (a) obtained by combining an image with low tagging frequency (b) and an image with high tagging frequency (c). Dyskinetic tissue with stretching (1 in a) is represented by a hyperintense area on the low-frequency image and by a hypointense area on the high-frequency image. Akinetic myocardial tissue (2 in a), in which there is no contraction, has an appearance identical to that of surrounding static tissue (ie, chest wall or liver). Severely hypokinetic tissue (3 in a) and normally contracting subendocardial or midwall tissue (4 and 5 in a) show an inverse intensity pattern directly related to the strain values on a pixel-by-pixel basis. (d-f) Short-axis strain-encoded MR images obtained in a 68-year-old woman after myocardial infarction. The low-frequency image (d) shows subendocardial hyperintense areas (arrows) that indicate myocardial dysfunction; the same areas are represented in red on the composite color-coded image (e). Delayed-enhancement image (f) shows a subendocardial area of hyperenhancement (arrows) in the region of the left anterior descending artery that represents chronic myocardial infarction and that corresponds with the areas of dysfunction depicted on the strain-encoded images.

View larger version (110K): [in a new window]   Figure 9e.  Through-plane strain information obtained with strain-encoded MR imaging. (a-c) Longitudinal shortening is displayed on a composite short-axis image (a) obtained by combining an image with low tagging frequency (b) and an image with high tagging frequency (c). Dyskinetic tissue with stretching (1 in a) is represented by a hyperintense area on the low-frequency image and by a hypointense area on the high-frequency image. Akinetic myocardial tissue (2 in a), in which there is no contraction, has an appearance identical to that of surrounding static tissue (ie, chest wall or liver). Severely hypokinetic tissue (3 in a) and normally contracting subendocardial or midwall tissue (4 and 5 in a) show an inverse intensity pattern directly related to the strain values on a pixel-by-pixel basis. (d-f) Short-axis strain-encoded MR images obtained in a 68-year-old woman after myocardial infarction. The low-frequency image (d) shows subendocardial hyperintense areas (arrows) that indicate myocardial dysfunction; the same areas are represented in red on the composite color-coded image (e). Delayed-enhancement image (f) shows a subendocardial area of hyperenhancement (arrows) in the region of the left anterior descending artery that represents chronic myocardial infarction and that corresponds with the areas of dysfunction depicted on the strain-encoded images.

View larger version (105K): [in a new window]   Figure 9f.  Through-plane strain information obtained with strain-encoded MR imaging. (a-c) Longitudinal shortening is displayed on a composite short-axis image (a) obtained by combining an image with low tagging frequency (b) and an image with high tagging frequency (c). Dyskinetic tissue with stretching (1 in a) is represented by a hyperintense area on the low-frequency image and by a hypointense area on the high-frequency image. Akinetic myocardial tissue (2 in a), in which there is no contraction, has an appearance identical to that of surrounding static tissue (ie, chest wall or liver). Severely hypokinetic tissue (3 in a) and normally contracting subendocardial or midwall tissue (4 and 5 in a) show an inverse intensity pattern directly related to the strain values on a pixel-by-pixel basis. (d-f) Short-axis strain-encoded MR images obtained in a 68-year-old woman after myocardial infarction. The low-frequency image (d) shows subendocardial hyperintense areas (arrows) that indicate myocardial dysfunction; the same areas are represented in red on the composite color-coded image (e). Delayed-enhancement image (f) shows a subendocardial area of hyperenhancement (arrows) in the region of the left anterior descending artery that represents chronic myocardial infarction and that corresponds with the areas of dysfunction depicted on the strain-encoded images.

View larger version (118K): [in a new window]   Figure 10a.  Midventricular short-axis end-systolic cine MR images based on data obtained with the DENSE technique during a single breath-hold in a healthy volunteer. (a) Magnitude-reconstructed image. (b) Two-dimensional displacement map computed from a phase-reconstructed image. Each vector in the map represents the end-diastolic-to-end-systolic motion of the myocardium as depicted in a single pixel. (c) Color-coded myocardial strain map shows circumferential shortening, which was computed from the displacement field. (Courtesy of D. Kim, W. D. Gilson, C. M. Kramer, and F. H. Epstein, University of Virginia Health System, Charlottesville, Va.)

View larger version (52K): [in a new window]   Figure 10b.  Midventricular short-axis end-systolic cine MR images based on data obtained with the DENSE technique during a single breath-hold in a healthy volunteer. (a) Magnitude-reconstructed image. (b) Two-dimensional displacement map computed from a phase-reconstructed image. Each vector in the map represents the end-diastolic-to-end-systolic motion of the myocardium as depicted in a single pixel. (c) Color-coded myocardial strain map shows circumferential shortening, which was computed from the displacement field. (Courtesy of D. Kim, W. D. Gilson, C. M. Kramer, and F. H. Epstein, University of Virginia Health System, Charlottesville, Va.)

View larger version (67K): [in a new window]   Figure 10c.  Midventricular short-axis end-systolic cine MR images based on data obtained with the DENSE technique during a single breath-hold in a healthy volunteer. (a) Magnitude-reconstructed image. (b) Two-dimensional displacement map computed from a phase-reconstructed image. Each vector in the map represents the end-diastolic-to-end-systolic motion of the myocardium as depicted in a single pixel. (c) Color-coded myocardial strain map shows circumferential shortening, which was computed from the displacement field. (Courtesy of D. Kim, W. D. Gilson, C. M. Kramer, and F. H. Epstein, University of Virginia Health System, Charlottesville, Va.)