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Updated: Aug 2, 2025
Contrast-Enhanced Subharmonic Aided Pressure Estimation SHAPE Using Ultrasound Imaging with a Focus on Identifying Portal Hypertension
Published on: December 5, 2020
Contrast-enhanced subharmonic aided pressure estimation for assessment of intracranial pressure in vivo
Abby C Larson1, Anush Sridharan2, James K Moon1
1Department of Surgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
Insights
Subharmonic aided pressure estimation (SHAPE) shows promise for noninvasive intracranial pressure (ICP) monitoring. This novel ultrasound technique correlated well with invasive ICP measurements in fetal lambs, suggesting a potential for safer pediatric monitoring.
Area of Science:
- Medical Imaging
- Ultrasound Technology
- Pediatric Monitoring
Background:
- Current intracranial pressure (ICP) monitoring in children relies on invasive methods.
- Subharmonic aided pressure estimation (SHAPE) is an ultrasound technique for measuring fluid pressures.
- SHAPE's application for ICP measurement is unexplored.
Purpose of the Study:
- To evaluate SHAPE as a noninvasive tool for ICP assessment.
- To investigate SHAPE's utility in a fetal lamb model.
Main Methods:
- Eighteen fetal lambs underwent ICP catheterization.
- Contrast-enhanced ultrasound (CEUS) with SHAPE was used to image the brain.
- SHAPE intensity values were correlated with measured ICP during induced pressure changes.
Main Results:
- A statistically significant inverse correlation was observed between SHAPE intensity and ICP.
- This inverse relationship was found in both whole brain and thalamic measurements.
- Median Spearman's rho values were -0.58 for the whole brain and -0.56 for the thalami.
Conclusions:
- SHAPE intensity demonstrates a significant inverse correlation with in vivo ICP.
- This study validates SHAPE as a potential noninvasive ICP measurement technique in an animal model.
- SHAPE may offer a safer alternative for ICP monitoring, particularly in pediatric patients.
Background:
Intracranial pressure (ICP) monitoring in children currently requires invasive techniques. Subharmonic aided pressure estimation (SHAPE) uses contrast-enhanced ultrasound (CEUS) to measure intravascular and interstitial pressure, but utility in ICP measurements has yet to be explored.
Objective:
The objective of this study was to investigate SHAPE as a novel tool for noninvasive ICP measurements in fetal lambs.
Materials And Methods:
Eighteen fetal lambs at 107-139 days gestational age (term = 145 days) underwent subdural ICP catheter placement. The brain was imaged in the coronal plane in CEUS mode optimized for SHAPE, while infusing an US contrast agent into the fetal circulation. After SHAPE calibration, saline was infused via the subdural catheter to increase ICP. Five-second SHAPE cine clips were obtained at various ICPs. Subharmonic intensity values of the whole brain and thalami were correlated with ICP values using mixed effects linear regression analyses and the strength of the relationship was evaluated by Spearman's rank-order correlation.
Results:
Forty-nine experiments produced 723 datapoints, including SHAPE intensity values and mean ICP measurements. There was a statistically significant inverse relationship between SHAPE intensity values and ICP measurements in the whole brain and thalami (median rho value - 0.58 and - 0.56, respectively).
Conclusion:
SHAPE intensity values of the brain demonstrate an inverse and statistically significant correlation with in vivo ICP measurements in an animal model.
