The most common cause of hindlimb lameness in dogs is cranial cruciate ligament rupture. In 48-77.3% of the population this trauma leads to secondary damage of the meniscus. Depending on the magnetic strength of the used device, different diagnostic accuracy can be achieved. The examination sensitivity of magnetic resonance imaging is affected by many factors which are independent of diagnostic strength, such as correct positioning of the patient, size of the stifle joint examined, or selection of the right protocol of sequences. Sensitivity of meniscus damage detection was 100% and 90%, respectively, in high-and low-field magnetic resonance. The best results were reported during examination of the stifle in dogs above 10 kg b.w. at a flexion angle of 145 o , and in sagittal and dorsal planes. Regardless of the magnetic strength applied, imaging of the whole cranial cruciate ligament is difficult. Moreover, MRI allows the detection of the first signs of osteoarthritis, which were observed 4 and 6 weeks after rupture of the cranial cruciate ligament using high and low-field MRI. This also applies to lesions in the subchondral bone or a bone marrow which occurred in association with insufficiency of the stifle joint, and were mainly localized in the epiphysis of the femur and tibia. The present article provides a comparison of different examination protocols and images of damaged stifle structures, such as menisci, ligaments and bones of the stifle joint visualized with low-field and high-field magnetic resonance. Magnetic resonance arthrography is also discussed.

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.

Otitis media is a common disease in clinical veterinary practice. Although low-field magnetic resonance imaging reports for otitis media in dogs exist, in cats detailed information is missing. Radiography is helpful in diagnosing chronic inflammation, but may be insufficient during the initial phase of inflammation. For this reason, this report describes the magnetic resonance findings in two cats with otitis media. In both cases, middle ear empyema was detected. Magnetic resonance imaging of middle ear disorders in cats should contain pre-and post-contrast T1-weighted sequences in the dorsal and transverse planes, a T2-weighted sequence in the dorsal and transverse planes and a fluid-attenuated inversion recovery sequence in the dorsal or transverse planes. On pre-contrast T1-weighted images, the empyema had an intensity similar to that of brain tissue with a delicate hyper-intensity in the middle. On post-contrast T1-weighted images, the material had non-uniform enhancement in the dorsolateral compartment and circumference enhancement in the ventromedial compartment of the tympanic bulla with a hypo-intense centre. On T2-weighted images, the mass had heterogeneously increased signal intensity to brain tissue, but was less intense than cerebrospinal fluid. In the fluid-attenuated inversion recovery sequence, the pathological lesion was distinctly hyper-intense in comparison to other tissues with a narrow area of increased signal intensity in the middle of the ventromedial tympanic bulla compartment. Magnetic resonance imaging is commonly used for the visualisation of different disorders of the membranous labyrinth and allows the differentiation of chronic hematomas, empyemas and middle and internal ear neoplasia. The recommended magnetic resonance protocol of the middle ear should include pre-and post-contrast T1 sequences in the dorsal and transverse planes, the T2 sequence in the dorsal and transverse planes and the fluid-attenuated inversion recovery sequence in the dorsal or transverse planes.

This article presents a case report in which complex deformities of the canine stifle joint were visualised using 3D volume rendering of images acquired in a low-field MRI system. The use of low-field MRI for 3D volume rendering has been described in human medicine, but no such reports are available as yet in veterinary medicine. A two-year-old male mongrel dog (8.5 kg body mass) with an unknown previous history of hindlimb lameness was presented to our clinic. The left stifle joint was hyperextended, slightly enlarged and it showed a limited range of motion. Three-dimensional sequences were used to visualise bones of the stifle joint. Optimal values of in-plane spatial resolution were obtained for small structures. The developed 3D model contributed to our understanding of the spatial localisation of bone deformities in the patient, which was crucial in surgical planning. This report shows that three-dimensional models do significantly enhance the clinical applicability of low-field MRI.

ABSTRACT:We describe here a case study of a 16-month-old female European shorthair cat examined about 6 months after the osteosynthesis of a femoral fracture. Clinical examination revealed a non-weightbearing left limb, pain upon manipulation of the hip joint, complete immobilisation of the stifle joint and muscle atrophy in the left thigh. Low-field magnetic resonance images were acquired in sagittal, transverse and dorsal planes with T1-weighted spin echo, T2-weighted fast spin echo, T1-weighted gradient echo, gradient echo short tau inversion recovery and T1-weighted XBone sequences. Total examination time was 59 min 20 s. The obtained images revealed the presence of osteophytes on the surface of the femoral head, subluxation of the hip joint, atrophy and fatty infiltration of the quadriceps femoris muscle. The symmetry and size of callus in the fracture site were also evaluated. Based on the results of the magnetic resonance imaging exam, the patient was diagnosed with hip osteoarthritis, atrophy and fatty degeneration of the quadriceps femoris muscle with homogeneous and symmetrical distribution of callus in the fracture site. The results of this study confirm the high diagnostic value of low-field magnetic resonance imaging in diagnostics of musculoskeletal injuries in cats.