For those of you interested in CT and MRI, we have another great case from the CT/MRI society. This is a 2 year old mixed bree dog who presented for a two week history of progressive neurologic signs including ataxia and circling to the left. Enjoy the case!

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This week we have a CT/MRI society case contributed by Dr. Mathieu Spriet from the University of California, Davis. It’s an interesting MRI case for all you equine people. Enjoy!

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This week we have a case from the CT/MRI society of the American College of Veterinary Radiology. Enjoy the case!

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This week’s case is from the CT/MRI society, and is written by Bernard Walsh. Enjoy!

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This week we have a case from the CT/MRI society of the ACVR. Enjoy!

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This week we have an MR neuro case for you to enjoy from the CT/MRI society of the ACVR.

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Today’s case is a 17 year old female neutered Yorkshire Terrier with history of a seizure-like episode. Post your interpretations, answers will be available within the case on Monday as usual.

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This week we have a case contributed by the CT/MRI Society of the ACVR. These cases are a great chance to learn cross-sectional imaging from veterinary radiologists all over the world.

This week we are featuring a case from the CT/MRI Society of the ACVR. If you’re interested in membership in the society, visit the Web site for details. Membership includes access to these great cases as they are published, and 25% off books from Wiley Blackwell.

For everyone who needs to learn (or relearn) imaging neuroanatomy , there is an excellent new MRI brain atlas of the dog available for reference on the web. It has detailed, labeled images of the canine brain acquired with a 3T magnet in 3mm slices. The images in transverse section are viewed alongside stained and labeled images of the corresponding tissue section. There’s even a self-assessment to test your knowledge. Many thanks to Travis Saveraid, T. Fletcher, and the University of Minnesota for providing such a great resource.

This week we have a great case provided by the ACVR’s CT/MRI society. Dr. Silke Hecht of the University of Tennessee is the author. These cases are a chance for you to expand your knowledge in cross-sectional imaging, so take a look.

Members of the CT/MRI society are contributing cases to their case of the month feature on a regular basis. There will be a wide variety of cross sectional imaging clinical cases to see and learn from! The cases are immediately available to society members on the ACVR website, then the following month for the general public. Take this opportunity to see interesting cases and expert opinions from members of the CT/MRI society! This month’s case is courtesy of Dr. Laura Armbrust, Associate Professor of Radiology at Kansas State University.

CT/MRI Society Case of the Month

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We all think of MR as a diagnostic tool to let us look inside the brain for signs of disease. It gives fantastic anatomical detail and contrast between tissues. Functional MR, or fMRI, is becoming a popular tool in investigating how the brain works. It measures changes in blood flow in different regions of the brain as people perform certain tasks. This information allows us to relate function and structure.

Of course, the advertising industry is very interested in how their products affect our brains. Only 50% of ads trigger any response, and they are the ones people like. Does this mean that ads we dislike are more effective? Read the whole story at Analyst Cafe.

Radio Australia’s All in the Mind recently investigated the effects of fMRI on science and journalism. Dr. Jonica Newby, a former veterinarian and broadcaster, contributed to the podcast panel discussion. One of the topics was the news generating potential of these scientific fMRI studies, since people have a fascination with the brain and how it works. Since the science is still in its infancy, what do the results mean? Are science and the media exaggerating the conclusions past the strength of the evidence? It’s worth a read or a listen.

This is a technology we’ll be hearing more about in the media and in scientific journals. It may have applications in veterinary medicine, such as in evaluating the optical pathways in dogs. But the need for general anesthesia in animal patients makes interpreting the brain scans even more difficult. Hopefully we’ll see more research on this in the future.

We had a bit of a hiatus in KCC for the last couple of weeks with the residents preparing for written boards, and various people being away. But tonight we reconvened to do some alternate imaging cases, including CT and MR.

One case was a dog with an extra-axial, broad-based, strongly contrast-enhancing mass in the left skull base that was compressing the brain stem. On the GRE images, there was focal loss of signal from susceptibility artifact due to hemorrhage. We all agreed that the strong contrast enhancement meant the mass was extra-axial, since it would be outside the blood-brain-barrier. Normal brain does not contrast enhance, which brought up the question of whether an intra-axial mass could enhance similarly. Key points included the fact that an intra-axial mass enhances because of new blood vessel recruitment, and that higher grade gliomas enhance more strongly than low grade gliomas. The difference between an extra-axial mass and intra-axial mass would be uniformity of enhancement; gliomas tend to be heterogeneously enhancing, while meningiomas are more uniformly enhancing.

Another point that this case brought up was the different ways of looking for hemorrhage on MR. On spin-echo sequences, there are changes in intensity on T1 and T2 sequences as the blood degrades into hemoglobin derivatives over time. This often gives a mottled appearance. With GRE sequences, there is a signal void, or black area, where the degradation products from blood are located.

A second interesting case was a CT of a stray dog with mild hind limb lameness. There was a focal, soft tissue and mineral attenuating mass in the medulla of the proximal femur. It appeared to arise from the endosteum and expand into the medulla, and had a mineralized capsule with a broad base that blended back into cortical bone. There was some cortical thinning but no disruption. It had mostly benign characteristics and appeared to be arising primarily from bone. Benign primary bone tumors would include osteoma, osteochondroma, and enchondroma. This one turned out to be an osteoblastoma; very rare and luckily benign.

That’s all for this episode. KCC is winding down for the summer, but we may get to look at a few more cases before the end of the quarter.

At tonight’s KCC, we saw some great cases from the clinic this week. One of them was a 7 year old MN Vizsla with a history of inappetance, ataxia and fever. He had an MR performed, which showed multifocal areas of abnormality. There were lesions in the right cerebrum, left frontal lobe, and left cerebellum. All of the lesions had a component of hyperintensity on T1 and T2 weighted images. They were intra-axial, and the largest one in the cerebellum had both hyperintense and hypointense components. The large lesion was causing a mass effect with displacement of the brainstem and midline shift.

The cerebellar lesion showed rim enhancement with gadolinium, and had an “onionskin” appearance on T2 and Flair images. There was also edema surrounding this lesion on both sequences.

Differential diagnoses for an asymmetric, multifocal disease included metastatic neoplasia, infarction, granulomatous disease, or septic emboli such as in endocarditis. There was a definite hemorrhagic component because of the hyperintensity on T1 and T2 images.

The interesting point that came out was that the “onionskin” appearance usually means multiple episodes of hemorrhage have occured at different times. The intensity of the blood changes over time as it is transformed to different metabolites.

This animal had disseminated hemangiosarcoma, including the right atrium, lung and multiple abdominal organs.