Use of the T2*‐weighted Gradient Recalled Echo Sequence for Magnetic Resonance Imaging of the Canine and Feline Brain

Abstract

T2*-weighted magnetic resonance imaging (MRI) has been reported to help improve detection of intracranial hemorrhage and is widely used in human neuroimaging. To assess the utility of this technique in small animals, interpretations based on this sequence were compared with those based on paired T2-weighted and fluid-attenuated inversion recovery (FLAIR) sequences in 200 dogs and cats that underwent brain MRI for suspected intracranial disease. Two sets of images (T2 + FLAIR and T2*) were reviewed separately in random order unaccompanied by patient information and were interpreted as normal or abnormal based on whether intracranial abnormalities were seen. The number and location of intracranial lesions were recorded. Eighty-five studies were considered normal and 88 were considered abnormal based on both sets of images, with good agreement (κ = 0.731) between the two. Susceptibility artifact was present in 33 cases (16.5%) on T2*-weighted images. In 12 cases (6%) a total of 69 lesions were seen on T2*-weighted images that were not seen on T2/FLAIR, all of which were associated with susceptibility artifact caused by presumed intracranial hemorrhage. Pseudolesions were seen on T2*-weighted images in five cases, none of which were associated with susceptibility artifact. Abnormalities were seen on T2/FLAIR images that were not seen on T2*-weighted images in 35 cases, confirming that T2* does not replace standard spin echo sequences. These results support inclusion of T2*-weighted sequences in small animal brain MRI studies and indicate that that a large number of abnormalities (especially hemorrhagic lesions) can go undetected if it is not performed.

Putative Cerebral Microbleeds in Dogs Undergoing Magnetic Resonance Imaging of the Head: A Retrospective Study of Demographics, Clinical Associations, and Relationship to Case Outcome

“…These signal voids correlate with collections of blood or blood products on histopathology, often in association with vascular disease, in people . In dogs, putative CMBs (pMBs) also have been identified, and preliminary results suggest that histopathology of these lesions bears similarities to human CMBs …”

“…2,3 In dogs, putative CMBs (pMBs) also have been identified, and preliminary results suggest that histopathology of these lesions bears similarities to human CMBs. [4][5][6] In people, CMBs occur at low frequency in the general population, 7 and prevalence increases with age. 8,9 Affected people often are minimally symptomatic, but CMBs have been shown to be reliably associated with small vessel pathology and have proven to be predictive of future clinically relevant disease states.…”

Consensus recommendations on standardized magnetic resonance imaging protocols for multicenter canine brain tumor clinical trials

“…Recommended sequence protocols should include, at a minimum, pre‐ and postcontrast three‐dimensional T1‐weighted images, T2‐weighted turbo spin echo (TSE) in all three planes, T2*‐weighted gradient recalled echo, T2‐weighted fluid attenuated inversion recovery (FLAIR), and diffusion weighted imaging/diffusion tensor imaging in transverse plane (Table ). The rationale for these sequences is described in more detail below, with consideration of relevant veterinary‐specific MRI literature . To maximize scanning efficiency, recommendations as to the order of scanning are presented in Table and described later in the text.…”

Diagnosis of cerebral ventriculomegaly in felines using 0.25 Tesla and 3 Tesla magnetic resonance imaging

“…To scan brain tissues, T1-weighted, T2-weighted and fluid attenuated inversion recovery sequences are used most frequently (Benigni and Lamb 2005;Cherubini et al 2008;Hecht and Adams 2010;Hodshon et al 2014). T1-weighted images are considered to be more useful in evaluations of brain anatomy while T2-weighted images better describe pathology (Benigni and Lamb 2005;Cherubini et al 2008;Hecht and Adams 2010;Hodshon et al 2014).…”