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Updated: Jun 6, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Time spatial labeling inversion pulse cerebral MR angiography without subtraction by use of dual inversion recovery
Yoshiyuki Ishimori1, Masahiko Monma, Hiraku Kawamura
1Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki, 300-0394, Japan. ishimori@ipu.ac.jp
Abstract:
Time-spatial labeling inversion pulse (time-SLIP), which is a technique of nonenhanced magnetic resonance angiography (MRA) based on arterial spin labeling (ASL), is used in various situations. Although subtraction between the images obtained with and without ASL is usually employed in cerebral time-SLIP MRA, to reduce the imaging time, dual inversion recovery (IR) has been applied for suppression of the background signals in this study. Appropriate timings for the 1st IR, 2nd IR, and the interval of data acquisition were investigated using computer simulation and a phantom experiment. With a short interval of data acquisition, the visibility of the simulated vessel was inadequate because replacement of the suppressed flow was insufficient. With a long interval of data acquisition, the contrast between the vessel and background was reduced. The reasons for this appeared to be the following: the longitudinal magnetization of the replaced flow is reduced because of the prolonged 2nd inversion time, causing a mismatch of the null point between the calculated and the actual values to become prominent. As a result, 3-4 s seemed to be an appropriate interval for data acquisition. Sufficient angiographic information could be obtained by use of dual IR background suppression in a volunteer study. With this technique, cerebral time-SLIP MRA can be performed in half of the imaging time required with the conventional subtraction technique.
Insights
Dual inversion recovery (IR) background suppression in time-spatial labeling inversion pulse (time-SLIP) magnetic resonance angiography (MRA) significantly reduces imaging time. This optimized technique achieves sufficient angiographic information with dual IR, halving the time needed compared to conventional methods.
Area of Science:
- Medical Imaging
- Radiology
- Biophysics
Background:
- Time-spatial labeling inversion pulse (time-SLIP) is a nonenhanced magnetic resonance angiography (MRA) technique utilizing arterial spin labeling (ASL).
- Conventional cerebral time-SLIP MRA typically employs image subtraction, which can be time-consuming.
- Background signal suppression is crucial for improving image quality and reducing scan duration.
Purpose of the Study:
- To investigate the efficacy of dual inversion recovery (IR) for background signal suppression in time-SLIP MRA.
- To optimize the timing parameters for dual IR, including the 1st IR, 2nd IR, and data acquisition interval.
- To reduce the overall imaging time for cerebral time-SLIP MRA.
Main Methods:
- Computer simulations and phantom experiments were conducted to determine optimal timings.
- Investigated the impact of varying data acquisition intervals on vessel visibility and contrast.
- Evaluated the dual IR technique in a volunteer study for cerebral time-SLIP MRA.
Main Results:
- Short data acquisition intervals resulted in inadequate vessel visibility due to insufficient flow replacement.
- Long data acquisition intervals led to reduced contrast between vessels and background.
- An optimal data acquisition interval of 3-4 seconds was identified.
- Dual IR background suppression successfully provided sufficient angiographic information in volunteer studies.
Conclusions:
- Dual inversion recovery is an effective method for background suppression in time-SLIP MRA.
- Optimized timing parameters, particularly a 3-4 second acquisition interval, are crucial for successful implementation.
- This dual IR technique can significantly reduce cerebral time-SLIP MRA imaging time by approximately 50% compared to subtraction methods.
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