Apparent vascular occlusion on cranial TOF MRA with peripheral presaturation technique
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Updated: Nov 8, 2026
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Published on: August 11, 2023
1Department of Radiology, Jewish Hospital, Washington University Medical Center, Washington University School of Medicine, St. Louis, MO 63110.
Objective:
Improvement in the visibility and accurate representation of intracranial vessels may be achieved on cranial time-of-flight (TOF) MR angiography (MRA) when the signal intensity of orbital and superficial fat is suppressed. This may be accomplished by placement of spatial radiofrequency presaturation bands along the periphery of the head. The objective of this study was to evaluate the potential for this peripheral presaturation technique to result in a spurious appearance of vascular occlusion.
Materials And Methods:
Three-dimensional TOF MRA of the head was performed in three patients. Flow-compensated spoiled gradient echo images were acquired in the transaxial plane, using the peripheral presaturation technique. The MRA acquisitions were then subsequently repeated in each patient following retraction of the peripheral presaturation bands. A phantom study was also performed to assess the slice profile of the presaturation bands.
Results:
There was absence of flow-related enhancement, indicating apparent vascular occlusion, involving one carotid siphon in each patient on initial MRA images. Following lateral retraction and/or removal of presaturation bands, the carotid siphons were documented to be patent, with normal caliber and flow-related enhancement demonstrated. Image analysis and phantom experiments indicate this vascular pseudoocclusion is due to proximity of the lateral presaturation band to the lateral aspect of the petrous segment of the internal carotid artery. In this location, there is inadvertent saturation of flowing spins due to imperfections in the presaturation band slice profile.
Conclusion:
The use of peripheral presaturation bands for cranial TOF MRA is useful for improving vascular depiction. However, patent vessels may occasionally demonstrate an absent signal intensity, suggesting occlusion when this technique is used. Awareness of this diagnostic pitfall is important so that serious misdiagnosis does not occur.
Insights
Peripheral presaturation bands improve cranial TOF MRA but can cause false positives for vascular occlusion. Awareness of this potential pitfall is crucial to avoid misdiagnosis in neuroimaging.
Area of Science:
- Neuroimaging
- Radiology
- Vascular Imaging
Background:
- Cranial time-of-flight MR angiography (TOF MRA) benefits from suppressing superficial fat signals.
- Spatial radiofrequency presaturation bands can achieve this suppression.
- Potential for artifacts with peripheral presaturation needs evaluation.
Purpose of the Study:
- To assess if peripheral presaturation bands in cranial TOF MRA can create a false appearance of vascular occlusion.
- To investigate the diagnostic implications of this technique.
Main Methods:
- Performed 3D TOF MRA of the head in three patients with and without peripheral presaturation bands.
- Acquired flow-compensated spoiled gradient echo images.
- Included a phantom study to evaluate presaturation band slice profiles.
Main Results:
- Initial MRA showed apparent carotid siphon occlusion in all patients.
- Subsequent MRA with band retraction revealed patent vessels with normal enhancement.
- Pseudoocclusion linked to presaturation band proximity and imperfect slice profiles.
Conclusions:
- Peripheral presaturation bands enhance cranial TOF MRA visualization.
- This technique can lead to false-positive findings of vascular occlusion.
- Radiologists must be aware of this diagnostic pitfall to prevent misdiagnosis.
