Abstract illustration of a canine blood sample in an MRI machine, visualizing magnetic fields and signal changes.

Decoding Dog Blood: What Low-Field MRI Reveals About Canine Health

Beau Callahan in Health & Wellness August 2025 • 5 min read.

"An in-depth look at how low-field MRI technology is enhancing the diagnosis of canine conditions through blood analysis, exploring its potential and limitations."

Low-field magnetic resonance imaging (MRI) is increasingly valuable in veterinary medicine, particularly for imaging the central nervous system, including the brain and spine. While higher field strength MRIs are becoming more common in academic settings, low-field MRI remains a staple in veterinary practices due to its cost-effectiveness. However, this lower cost comes with reduced specifications, making it challenging to differentiate specific lesions, such as hemorrhages, within intracerebral and epidural spaces.

The appearance of hemorrhage in MRI scans can vary significantly based on factors like the age of the blood. Accurate diagnosis of intracranial and epidural hemorrhages is challenging, especially with low-field MRI. Both intrinsic factors, such as the time since the bleeding started, and extrinsic factors, like the pulse sequence and field strength used, influence the MRI signal intensity of a hemorrhage.

Recognizing the need for better understanding, a study was conducted to assess time-sensitive magnetic resonance (MR) changes in canine blood using low-field MR. This article delves into the findings of that study, exploring how canine blood changes over time in MRI scans and what these changes can tell us about a dog's health.

Unlocking Insights: How Canine Blood Changes Appear on Low-Field MRI

Abstract illustration of a canine blood sample in an MRI machine, visualizing magnetic fields and signal changes.

The study involved collecting arterial and venous blood samples from eight healthy beagle dogs. These samples were then placed in tubes and imaged at regular intervals over 30 days using various MRI sequences, including T1-weighted (T1W), T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR), short tau inversion recovery (STIR), and T2-star gradient-echo (T2-GRE).

Visual analysis of the images revealed the development of both relatively homogenous and heterogeneous blood clots. Key changes were observed, particularly around days 2 and 13, where the margination of the clot and plasma changed significantly. By day 2, the heterogeneous blood clots showed distinct signal layers in T2W, T1W, and especially STIR images.

T1-weighted (T1W): Shows detailed anatomical structures, with fat appearing bright and water appearing dark.
T2-weighted (T2W): Highlights areas with high water content, making fluids appear bright.
Fluid-Attenuated Inversion Recovery (FLAIR): Suppresses fluid signals, making it easier to detect lesions near fluid-filled spaces.
Short Tau Inversion Recovery (STIR): Highly sensitive to fluid and inflammation, with fat signals suppressed.
T2-star Gradient-Echo (T2-GRE): Sensitive to magnetic field distortions, useful for detecting blood products and hemorrhages.

Interestingly, hypointense signal layers were detected in the blood clots in STIR images, showing T2 hypo, FLAIR hypo, and T1 hyper intense signals. These signal layers remained relatively consistent until around day 13. Overall, the complex nature of hematomas on low-field MRI suggests that accurately characterizing hemorrhages and predicting clot age using this method alone may not be reliable.

Navigating the Future: What These Findings Mean for Canine Care

This study highlights the intricacies of using low-field MRI to assess canine blood characteristics and diagnose related conditions. The complex changes observed in blood clots over time indicate that relying solely on low-field MRI for accurate hemorrhage characterization and clot age prediction may be challenging.

Veterinarians and researchers can use these findings to better understand the limitations and potential of low-field MRI in diagnosing canine health issues. By recognizing the specific signal changes and their timelines, clinicians can improve their interpretation of MRI scans and integrate this information with other diagnostic tools for more accurate assessments.

Further in vivo studies are essential to fully explore the chronological low-field MR signal intensity changes in hemorrhages. These future investigations could refine diagnostic protocols, enhancing the ability to detect and manage various conditions affecting canine health. With continued research, low-field MRI can become an even more valuable asset in veterinary medicine, aiding in more precise and timely interventions.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.4142/jvs.2016.17.1.103, Alternate LINK

Title: Time-Dependent Low-Field Mri Characteristics Of Canine Blood: AnIn VitroStudy

Subject: General Veterinary

Journal: Journal of Veterinary Science

Publisher: The Korean Society of Veterinary Science

Authors: Jimo Jeong, Sangjun Park, Eunseok Jeong, Namsoo Kim, Minsu Kim, Yechan Jung, Youngkwon Cho, Kichang Lee

Published: 2016-01-01

Everything You Need To Know

Why is low-field MRI still a common tool in veterinary practices if higher field strength MRIs offer better image quality?

Low-field MRI is used in veterinary medicine because it is cost-effective, making it accessible for many practices. While high-field MRI offers superior image quality, the financial advantages of low-field MRI make it a practical choice for initial diagnoses and monitoring canine conditions. However, the reduced specifications of low-field MRI can pose challenges in differentiating specific lesions, such as hemorrhages, within intracerebral and epidural spaces. This means that while it's a great starting point, more advanced imaging techniques might be necessary for a definitive diagnosis.

How does the age of a canine blood clot affect its appearance on low-field MRI, and what factors influence these changes?

The appearance of blood on low-field MRI scans changes over time due to factors like how long ago the bleeding started (intrinsic factors) and the type of MRI sequence used (extrinsic factors). The study examined how canine blood changed over 30 days using sequences like T1-weighted (T1W), T2-weighted (T2W), fluid-attenuated inversion recovery (FLAIR), short tau inversion recovery (STIR), and T2-star gradient-echo (T2*-GRE). These changes influence the signal intensity, making accurate hemorrhage diagnosis complex.

Can you explain the role of different MRI sequences such as T1-weighted, T2-weighted, FLAIR, STIR, and T2*-GRE in analyzing canine blood?

T1-weighted (T1W) MRI highlights anatomical structures, showing fat as bright and water as dark. T2-weighted (T2W) MRI emphasizes areas with high water content, making fluids appear bright. FLAIR MRI suppresses fluid signals to detect lesions near fluid-filled spaces. STIR MRI is highly sensitive to fluid and inflammation, suppressing fat signals. T2*-GRE MRI is sensitive to magnetic field distortions, useful for detecting blood products and hemorrhages. These sequences each provide unique information that helps in characterizing different aspects of canine blood and tissue.

What specific changes were observed in canine blood clots over time in the study using low-field MRI, particularly around days 2 and 13?

The study found that blood clots in low-field MRI showed significant changes around days 2 and 13. On day 2, heterogeneous blood clots displayed distinct signal layers in T2W, T1W, and STIR images. Hypointense signal layers were detected in STIR images, showing T2 hypo, FLAIR hypo, and T1 hyper intense signals. These layers remained consistent until around day 13. The complex nature of these changes suggests that accurately characterizing hemorrhages and predicting clot age using low-field MRI alone is not reliable.

What are the limitations of using low-field MRI to assess canine blood, and what does this imply for future advancements in veterinary diagnostics?

While low-field MRI is useful, the study indicates that it has limitations for accurate hemorrhage characterization and predicting clot age in dogs. The complex changes observed in blood clots over time mean that relying solely on low-field MRI might not provide a complete or precise diagnosis. Future research might focus on combining low-field MRI with other diagnostic tools or developing improved imaging techniques to enhance diagnostic accuracy in veterinary medicine. Understanding these limitations helps veterinarians make informed decisions about the best course of action for their patients.