From the Guidelines
Hyperemia on ultrasound is a significant finding that indicates increased blood flow and vascularity, which can be associated with inflammation, infection, or increased metabolic activity, and its detection should prompt further evaluation to determine the underlying cause. Hyperemia appears as increased color flow on Doppler imaging, which is a non-invasive and useful tool for assessing blood flow and perfusion in various tissues 1. This finding is not a diagnosis itself but rather a sign that requires correlation with clinical symptoms and possibly additional imaging or laboratory tests to determine the underlying cause. In the context of Crohn's disease, hyperemia can be an important finding, as it may indicate active inflammation or disease activity 1. The use of color Doppler ultrasound to assess hyperemia is a valuable tool in the evaluation of patients with Crohn's disease, particularly in pediatric patients 1.
Some common causes of hyperemia include:
- Acute inflammation, such as tendinitis, arthritis, or cellulitis
- Healing tissue after injury
- Tumor vascularity
- Physiologic responses, such as exercise-induced blood flow increases In the context of Crohn's disease, hyperemia can be associated with active inflammation, ulcers, or fistulas 1. The detection of hyperemia on ultrasound should prompt further evaluation, including clinical correlation, laboratory tests, and possibly additional imaging studies, such as MRI or CT scans 1.
The significance of hyperemia varies by anatomical location and clinical context, so interpretation should always consider the patient's complete clinical picture rather than viewing this finding in isolation 1. In clinical practice, the administration of oral contrast during abdominal US is uncommon, but it may be used in certain cases to enhance the sensitivity and specificity of the examination 1. Overall, hyperemia on ultrasound is an important finding that requires careful evaluation and correlation with clinical symptoms to determine the underlying cause and guide further management.
From the Research
Hyperemia on Ultrasound
- Hyperemia is a sign of active disease in the inflamed intestine and can be detected by Doppler sonography 2
- However, Doppler sonography can be limited by tissue motion artifacts and may not be able to detect intramural enteric vessel perfusion below the detection threshold
- Contrast Harmonic Imaging (CHI) at low Mechanical Index (MI) can be used to visualize vessels and detect hyperemia without these limitations 2
- CHI at low MI has been shown to be technically feasible for demonstrating increased intestinal perfusion in inflammatory bowel disease using a high-resolution ultrasound probe 2
Detection of Hyperemia
- Reactive hyperemia can be measured using various methods, including brachial artery velocity by Doppler ultrasound, tissue reperfusion by near-infrared spectroscopy, and peripheral artery tonometry 3
- Blunted reactive hyperemia is believed to reflect impaired microvascular function 3
- Hyperemia can be detected by analyzing gray scale values before and after injection of a contrast agent, such as BR 1, in regions of interest within the submucosal layer 2
Clinical Significance
- Hyperemia is an important indicator of active disease in various conditions, including inflammatory bowel disease 2
- Reactive hyperemia is a predictor of all-cause and cardiovascular morbidity and mortality 3
- Accurate detection and measurement of hyperemia are crucial for diagnosis, treatment, and management of related conditions 2, 3