EFFECTS OF STIFLE FLEXION ANGLE AND SCAN PLANE ON VISIBILITY OF THE NORMAL CANINE CRANIAL CRUCIATE LIGAMENT USING LOW-FIELD MAGNETIC RESONANCE IMAGING

The effect of CT and MRI with and without arthrography on the appearance of the feline carpal ligaments

Background

The current diagnosis of feline carpal injuries is based on radiographic examination including stress views and computed tomography; however, these techniques do not allow for direct evaluation of the carpal ligaments. The purpose of this cadaveric study was to assess the ability of CT arthrography (CTA) and MR arthrography (MRA) to provide this information using a single contrast mixture. A protocol for intra-articular injection of the feline carpus was also described. A contrast solution containing gadolinium and iohexol with a 50% gadolinium solution (Magnevist—gadolinium 0.5 mmol/mL diluted to a 0.05 mmol/mL solution) and 50% of iodine (Iohexol—iodine 300mgI/mL) was injected into the antebrachiocarpal and middle carpal joints of feline carpi using fluoroscopic guidance.

Results

CTA allowed for identification of intra-articular ligaments and the silhouette of select extra-articular ligaments when there was adequate joint distension, however it was not considered to be superior to MRI. MRA allowed for improved identification of the dorsal radiocarpal, accessorioulnocarpal, accessorioquartile, short ulnar and short radial collateral ligaments.

Conclusion

In this ex-vivo study, combined CTA and MRA enhanced the appearance of the feline carpal ligaments and may provide a foundation for future studies in the diagnosis of carpal injuries.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03463-6.

Assessment of the Usefulness of Image Reconstruction in the Oblique and Double-oblique Sagittal Planes for Magnetic Resonance Imaging of the Canine Cranial Cruciate Ligament

Introduction

The aim of the study was to determine the quality and significance of the magnetic resonance image of the canine knee after reconstruction in the oblique and double-oblique sagittal plane. This reconstruction and 3D images are rarely used in common protocols due to the longer study time they require. The study aimed to demonstrate significance for such diagnostic images in specific sequences in order to stimulate consideration of their more frequent use in diagnosis of diseases of the cruciate ligament in dogs.

Material and Methods

All tests were carried out using an open magnetic resonance tomography scanner with magnetic field induction. The images obtained from the 30 canine patients examined were reconstructed and evaluated by independent appraisers. Statistical analysis was performed.

Results

The study showed that MRI of the stifle joint using 3D sequences provides higher quality images of the cranial cruciate ligament in dogs. The results of the statistical analysis showed that multi-faceted reconstruction allows the secondary determination of the oblique imaging planes and obtains images of adequate quality.

Conclusion

It can be concluded that multi-faceted reconstruction facilitates the secondary determination of oblique imaging planes. This reconstruction additionally makes images available of better quality compared to the 2D sequence.

Accuracy of 3 Tesla magnetic resonance imaging using detection of fiber loss and a visual analog scale for diagnosing partial and complete cranial cruciate ligament ruptures in dogs

Canine cranial cruciate ligament rupture is often bilateral and asymmetrical, ranging from partial to complete rupture. The purpose of our diagnostic accuracy study was to assess the accuracy of 3 Tesla magnetic resonance imaging (MRI) detection of fiber loss and use of a visual analog scale in the diagnosis of complete versus partial cranial cruciate ligament rupture in 28 clinical dogs with unilateral complete rupture and contralateral partial rupture. Three Tesla MRI was performed on 56 stifles using sagittal sequences (T2-weighted fast spin echo with fat saturation, proton density fast spin echo, and T2-weighted 3D fast spin echo CUBE). Two MRI observers assessed the cranial cruciate ligament for fiber loss and completed a visual analog scale. The MRI data were compared to arthroscopy and clinical status. Accuracy classifying partial or complete rupture was assessed using receiver operating characteristic analysis. Compared to arthroscopy, for complete cranial cruciate ligament rupture, sensitivity, specificity, and accuracy of MRI detection of fiber loss were 0.78, 0.50-0.60, and 0.68-0.71, respectively, and, for partial tears, specificity was 1.00. An MRI visual analog scale score ≥79 was indicative of complete cranial cruciate ligament rupture (sensitivity 0.72-0.94 and specificity 0.71-0.84). Using a visual analog scale cut-point ≥79, observers achieved good accuracy discriminating clinical status of partial or complete cranial cruciate ligament rupture (area under the curve 0.87-0.93). MRI evaluation for fiber loss and use of a visual analog scale are specific in stifles with clinically stable partial cranial cruciate ligament rupture. In stifles with clinically unstable complete cranial cruciate ligament rupture, both MRI tests are sensitive though not specific compared to arthroscopy. As a diagnostic imaging method, MRI may help guide treatment in patients with cranial cruciate ligament damage, particularly for stable partial rupture.

Magnetic resonance imaging study in a normal Bengal tiger (Panthera tigris) stifle joint

Background

The purpose of this study was to describe the normal appearance of the bony and soft tissue structures of the stifle joint of a Bengal tiger (Panthera tigris) by low-field magnetic resonance imaging (MRI), and the use of gross anatomical dissections performed as anatomical reference. A cadaver of a mature female was imaged by MRI using specific sequences as the Spin-echo (SE) T1-weighting and Gradient-echo (GE) STIR T2-weighting sequences in sagittal, dorsal and transverse planes, with a magnet of 0.2 Tesla. The bony and articular structures were identified and labelled on anatomical dissections, as well as on the magnetic resonance (MR) images.

Results

MR images showed the bone, articular cartilage, menisci and ligaments of the normal tiger stifle. SE T1-weighted sequence provided excellent resolution of the subchondral bones of the femur, tibia and patella compared with the GE STIR T2-weighted MR images. Articular cartilage and synovial fluid were visualised with high signal intensity in GE STIR T2-weighted sequence, compared with SE T1-weighted sequence where they appeared with intermediate intensity signal. Menisci and ligaments of the stifle joint were visible with low signal intensity in both sequences. The infrapatellar fat pad was hyperintense on SE T1-weighted images and showed low signal intensity on GE STIR T2-weighted images.

Conclusions

MRI provided adequate information of the bony and soft tissues structures of Bengal tiger stifle joints. This information can be used as initial anatomic reference for interpretation of MR stifle images and to assist in the diagnosis of diseases of this region.