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MR imaging of hemorrhagic brain lesions: a comparison of dual-echo gradient- and spin-echo and fast spin-echo
E R Melhem1, R T Patel, R E Whitehead
1Department of Radiology, Boston University School of Medicine, Boston Medical Center, MA 02118, USA.
Objective:
Our objective was to assess the usefulness of the dual-echo gradient- and spin-echo (GRASE) technique in revealing acute hemorrhagic brain lesions and compare GRASE and fast spin-echo techniques for revealing acute hemorrhagic lesions and image artifacts.
Materials And Methods:
Thirty-two consecutive patients with acute intracranial hemorrhage underwent dual-echo GRASE (TEeff1/TEeff2, 35/85) and fast spin-echo (25/110) imaging. The techniques were matched for TR (3032 msec), spatial resolution, and acquisition time. Two neuroradiologists reviewed the images independently, documenting the number, size (<1, >1, or 1 cm in diameter), location, and signal characteristics (hypointense versus hyperintense compared with brain) of detectable lesions. These observers also compared matched T2- and proton density-weighted GRASE and fast spin-echo images for paramagnetic lesion conspicuity, diamagnetic susceptibility artifacts, chemical shift artifacts along the phase- and frequency-encoding directions, and artifactual CSF hyperintensity in the thin curvilinear cortical sulci and the Virchow-Robin spaces on only the proton density-weighted images.
Results:
The average number and conspicuity of dark (paramagnetic) lesions were significantly greater on GRASE than on fast spin-echo images (p < .05 and p < .001, respectively). We found no significant difference in the average number of bright lesions revealed by either technique (p > .1). Chemical shift artifacts along the phase-encoding directions were more prominent on GRASE than on fast spin-echo imaging. Chemical shift artifacts along the frequency-encoding directions and artifactual CSF hyperintensity were more prominent on fast spin-echo than on GRASE imaging. No visually apparent difference was found in the degree of diamagnetic susceptibility artifacts seen with the two techniques.
Conclusion:
Dual-echo GRASE imaging can be helpful in the examination of patients with suspected acute brain hemorrhage.
Insights
Dual-echo gradient- and spin-echo (GRASE) imaging better reveals acute hemorrhagic brain lesions than fast spin-echo techniques. GRASE imaging is helpful for examining patients with suspected acute brain hemorrhage.
Area of Science:
- Neuroradiology
- Medical Imaging
Background:
- Acute intracranial hemorrhage detection is crucial for patient management.
- Gradient- and spin-echo (GRASE) and fast spin-echo (FSE) are MRI techniques used for brain imaging.
Purpose of the Study:
- To evaluate the effectiveness of dual-echo GRASE in detecting acute hemorrhagic brain lesions.
- To compare GRASE and FSE techniques regarding lesion detection and image artifacts.
Main Methods:
- Thirty-two patients with acute intracranial hemorrhage underwent imaging using dual-echo GRASE and FSE sequences.
- Two neuroradiologists assessed lesion characteristics and compared artifact prevalence between the two techniques.
Main Results:
- GRASE demonstrated significantly higher conspicuity and average number of dark (paramagnetic) hemorrhagic lesions compared to FSE.
- No significant difference was observed in the detection of bright lesions.
- GRASE showed more prominent chemical shift artifacts along the phase-encoding direction, while FSE exhibited more prominent artifacts along the frequency-encoding direction and artifactual cerebrospinal fluid hyperintensity.
Conclusions:
- Dual-echo GRASE imaging is a valuable tool for evaluating acute brain hemorrhage.
- GRASE offers advantages in visualizing paramagnetic hemorrhagic lesions.