It’s been quite a year for Hallmarq’s Vision CT. Designed to bring fast 3D imaging to every equine practice, the walk-in-scan-walk-out system is safe, effective, and affordable. It offers the next step up from DR and is proving particularly effective when used in combination with our Standing Equine MRI.
A growing body of published, peer-reviewed clinical evidence is now widely available comparing Cone Beam CT (CBCT), Fan Beam CT (FBCT), and Magnetic Resonance Imaging (MRI). We take the opportunity to round up those papers in a year-end review:
Sagittal and Parasagittal Groove Fissures
Although no significant difference was observed between Cone-Beam CT (CBCT) and Fan-Beam CT (FBCT), it is important to note that the study was conducted using cadaveric limbs. Motion artifact, which can diminish image quality, is not accounted for in CBCT and MRI, thus rendering FBCT the most sensitive modality, since horses are under general anesthesia. Vanessa Peter, one of the authors, acknowledged that CBCT lacks sensitivity for detecting parasagittal groove fissures in live horses. Nevertheless, this study sheds light on the potential applications of CBCT in veterinary imaging.
Palmar Osteochondral Disease
Palmar/plantar osteochondral disease (POD) of the metacarpal/tarsal condyles is a common pathological finding in racehorses. This cross-sectional study compares diagnoses, imaging details, and measurements of POD lesions between Bone-Beam CT (CBCT), Fan-Beam CT (FBCT), and low-field magnetic resonance imaging (MRI) using macroscopic pathology as a gold standard. Thirty-five cadaver limbs from 10 horses underwent CBCT, FBCT, MRI, and macroscopic examination. CT and MR images were examined for the presence of POD, imaging details of POD, and measurements of POD dimensions and areas. Imaging diagnoses, details, and measurements were compared with macroscopic examination and between modalities.
Heterotopic mineralisation
Combining Cone-Beam CT (CBCT) and MRI can provide a more wholesome idea of the extent of the problem with everything performed on the standing horse, with no general anesthesia required. CBCT and FBCT systems were generally superior in identifying heterotopic mineralization than MRI. However, there were locations (mineralization of the oblique sesamoidean ligament and ossification of the joint capsule) where CBCT failed to identify abnormalities compared to FBCT. However, CBCT is not limited by general anesthesia.
MRI on the other hand, provided information on soft tissue pathology related to the lesions. This may be important for case management and detecting the importance of the condition as a lot of the heterotopic mineralization is considered an incidental finding
This paper supports that the combined utilization of CBCT and MRI offers a more comprehensive assessment of equine conditions, all conducted on standing horses without the necessity of general anesthesia. It would be prudent to avoid asserting that CBCT and FBCT yield identical results. This is because such a claim does not align with the study’s findings and because the study was conducted using cadaver limbs.
Fig. 1. Focal mineralization at the insertion of the suspensory ligament branches (Fetlock 2). CBCT standard (A) and bone (B) windows and the FBCT standard (C) and soft tissue (D) windows. The homogenous, hyper-attenuated mineralizations (arrows) were most evident on the standard and bone windows of the CBCT images and the soft tissue window of the FBCT image. Lateral is to the left.
Proximal Phalanx Dorsoproximnal Osteochondral Defects
Fan-Beam CT (FBCT) exhibited superior diagnostic performance compared to CBCT and MRI, positioning FBCT closer to the gold standard, particularly in discerning smaller-sized defects. However, CBCT demonstrated the second-highest diagnostic efficacy. When CBCT is coupled with MRI, a more comprehensive assessment of equine osteochondral conditions can be achieved, as MRI excels in evaluating the active stage of lesions. Utilizing standing imaging techniques may present a viable approach for diagnosing osteochondral defects. Motion artifact should be regarded as a notable limitation not considered in this study meaning that the sensitivity of both standing modalities may decrease further.
Notably, there were no discernible differences in the features of osteochondral defects between CT and low-field MRI, indicating that radiologists may not require specific training, as lesions exhibit similar appearances across these modalities.
And an early 2024 paper rightly has a place on this list too:
Imaging the metacarpo (MCP)/metatarsophalangeal (MTP) region
The study compared Cone Beam CT (CBCT – Hallmarq Vision CT) and low-field magnetic resonance imaging (MRI – Hallmarq Standing Equine MRI) findings in the metacarpo (MCP)/metatarsophalangeal (MTP) region of clinical patients imaged for diagnostic purposes. CBCT and low-field MRI contributed different diagnostic information so optimal information was obtained using both modalities. Standing CBCT showed changes in bone structure and attenuation, but was limited in detecting soft tissue injuries. Standing MRI showed increased fluid accumulation in bone and soft tissue injuries but was limited in assessing structural details of bone injuries.
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