Evaluation of Standard Magnetic Resonance Characteristics Used to Differentiate Neoplastic, Inflammatory, and Vascular Brain Lesions in Dogs

Abstract

Magnetic resonance (MR) imaging characteristics are commonly used to help predict intracranial disease categories in dogs, however, few large studies have objectively evaluated these characteristics. The purpose of this retrospective study was to evaluate MR characteristics that have been used to differentiate neoplastic, inflammatory, and vascular intracranial diseases in a large, multi‐institutional population of dogs. Medical records from three veterinary teaching hospitals were searched over a 6‐year period for dogs that had diagnostic quality brain MR scans and histologically confirmed intracranial disease. Three examiners who were unaware of histologic diagnosis independently evaluated 19 MR lesion characteristics totaling 57 possible responses. A total of 75 dogs with histologically confirmed intracranial disease were included in analyses: 51 with neoplasia, 18 with inflammatory disease, and six with cerebrovascular disease. Only strong contrast enhancement was more common in neoplasia than other disease categories. A multivariable statistical model suggested that extra‐axial origin, T2‐FLAIR mixed intensity, and defined lesion margins were also predictive of neoplasia. Meningeal enhancement, irregular lesion shape, and multifocal location distinguished inflammatory diseases from the other disease categories. No MR characteristics distinguished vascular lesions and these appeared most similar to neoplasia. These results differed from a previous report describing seven MR characteristics that were predictive of neoplasia in dogs and cats. Findings from the current study indicated that the high performance of MR for diagnosing canine intracranial diseases might be due to evaluator recognition of combinations of MR characteristics vs. relying on any one MR characteristic alone.

Multivoxel proton magnetic resonance spectroscopy of inflammatory and neoplastic lesions of the canine brain at 3.0 T

“…Investigators in 1 study 4 found that 7 MRI characteristics were significantly more common in patients with neoplasia than in patients with inflammatory and vascular disease. In a more recent study, 5 investigators found that only strong contrast enhancement was significantly more common in neoplastic lesions. Despite this lack of specificity regarding individual findings, conventional MRI has reasonable overall specificity for differentiating between broad etiologic categories of intracranial disease (neoplastic, inflammatory, or cerebrovascular).…”

“…Conventional MRI allows for evaluation of intracranial lesions and interpretation based on inherent macroscopic properties of the lesions (location, signal intensity, contrast enhancement, edema, and hemorrhage). Investigators in other studies 4,5 have found that conventional MRI findings for inflammatory and neoplastic lesions are often nonspecific, with overlapping imaging findings for the 2 conditions. Investigators in 1 study 4 found that 7 MRI characteristics were significantly more common in patients with neoplasia than in patients with inflammatory and vascular disease.…”

“…[6][7][8] The ability of clinicians to distinguish broad classes of disease with MRI is likely secondary to the summation and integration of all findings present to formulate a presumptive diagnosis. 5 Nonetheless, the criterion-ref- erenced standard for diagnosis of intracranial disease is histologic evaluation. [9][10][11] In veterinary medicine, a presumptive MRI diagnosis is often used for prognosis and treatment recommendations in disease conditions for which a definitive diagnosis would require biopsy.…”

Diagnosis and long‐term outcome in dogs with acute onset intracranial signs

“…, Young et al . ), as a final confirmative post mortem diagnosis was only obtained in three dogs. Fortunately, most dogs recovered from the acute neurological event and, as a consequence, owners were not motivated for post mortem investigation in dogs that were later euthanased due to unrelated causes.…”

Comparison of Two Fat‐suppressed Magnetic Resonance Imaging Pulse Sequences to Standard T2‐weighted Images for Brain Parenchymal Contrast and Lesion Detection in Dogs With Inflammatory Intracranial Disease

“…It was presumed that masses, especially those with defined margins, represent the lesion type that is least dependent on subtle differences in signal intensity to detect. Only records from animals with meningoencephalitis were searched in creation of the group with expected lesions, because masses are found less commonly in inflammatory brain disease than in neoplastic or vascular brain diseases, and inflammatory brain lesions rarely have defined margins . However we did not exclude animals with mass effect, and therefore did not eliminate the influence of mass effect on lesion detection altogether.…”