“Penny” is a 7 year-old Golden Retriever. She has been healthy until recently. She has had three seizure episodes in the last month. The seizures appear to be grand mal type with tonic and clonic muscle movements and brief loss of consciousness. Patient appears normal in between the episodes.
Magnetic resonance examination was carried out with a high field, superconducting unit. Sequences included T2 sagittal, T2 transverse, a Fluid Attenuation Inversion Recovery sequence (FLAIR) in the transverse plane, and T1 before contrast in the transverse plane. Gadolinium contrast agent was administered and T1 post-contrast images were obtained in all three planes. Each sequence has approximately 20-25 images and Figs 1-7 illustrate one image per sequence.
All sequences revealed normal anatomy and bilateral symmetry. The mild asymmetric changes within the lateral ventricles are commonly seen as a normal finding in this species. Magnetic resonance imaging has the ability to see macroscopic structural lesions larger than a grain of rice. Therefore, macroscopic structural lesions have been ruled out in this case. The seizures could be due to microscopic or physiologic/metabolic etiologies.
Magnetic resonance imaging is an expensive diagnostic test. The value of the test is also high. Dogs that are 7 years of age, when they have their first seizure, could have numerous diseases. The most common etiologies would include infectious conditions, cerebral infarction (strokes), brain tumors, or delayed onset of epilepsy.
An accurate diagnosis is needed for the proper therapeutic options. Early diagnosis can lead to improved treatment outcomes. Placing animals on anti-seizure medication without a proper diagnosis exposes the animal to medications that have significant serious side-effects. In this case, in the absence of a macroscopic finding, anti-seizure medication appears warranted. Proper therapy requires diligence in administering the medication and having blood levels checked for therapeutic levels. The veterinarian and owner can be confident that macroscopic structural lesions, including infarctions, infections, and tumors have been ruled out.
A proper study requires numerous sequences, as illustrated in this case. In addition, the interpretation needs to be done by a skilled professional with experience and the ability to distinguish pathologic change from similar appearing lesions that could be artifactual.
“Baxter” was a 2 year-old Golden Retriever. Baxter had a draining tract in his paw that had been surgically explored on three different occasions. Small pieces of wood were found, but there had been no resolution of the fistulous tracts. Dr. Haburjak, a veterinary surgeon, requested a magnetic resonance imaging study of the paw to better plan any further surgical intervention. The previous surgeries would have distorted the normal architecture severely and would make subsequent surgery difficult without an accurate “roadmap.” The magnetic resonance imaging study was carried out with a high field super-conducting magnet.
Sequences included STIR sequences in all three planes and T1-weighted images before and after contrast. The T1-weighted images were also performed with fat-saturation toreduce the fat signal and allow better visualization of the contrast enhancement.
An abnormality was seen that was within the soft tissues of the paw. The abnormality was between the deep digital flexor tendons and the metacarpal bones of the left paw. There was a hyperintense lesion that was seen on the STIR sequences from a fluid collection. The draining fistulous tracts were readily identified. At the center of the fluid was a hypointense structure that measured approximately 3.5 cm in length by 0.5 cm in width. There was a center to this material, which was compatible to a stick with a soft core or medullary cavity that was soaking up the fluid.
The lesion was midline between the third and fourth metacarpal regions and was deep to the flexor tendons. Surgery was performed and a stick of the size diagnosed by magnetic resonance was readily removed with the accurate roadmap for the surgeon. The images depict the abnormalities. There is also a post-operative image of the removed wood foreign body.
The use of magnetic resonance imaging provided the information needed for the proper and corrective surgery. MRI exams are costly, but if one calculates the direct and indirect cost of the previous 3 surgeries there was obviously a value to this examination. When we think of the pain and suffering, the value of a proper procedure often trumps the initial cost.