title: Magnetic resonance imaging characteristics of peripheral nerve sheath tumors of the canine brachial plexus in 18 dogs.
abstract: Magnetic resonance imaging (MRI) examinations from 18 dogs with a histologically confirmed peripheral nerve sheath tumor (PNST) of the brachial plexus were assessed retrospectively. Almost half (8/18) had a diffuse thickening of the brachial plexus nerve(s), six of which extended into the vertebral canal. The other 10/18 dogs had a nodule or mass in the axilla (1.2-338 cm3). Seven of those 10 masses also had diffuse nerve sheath thickening, three of which extended into the vertebral canal. The majority of tumors were hyperintense to muscle on T2-weighted images and isointense on T1-weighted images. Eight of 18 PNSTs had only minimal to mild contrast enhancement and many (13/18) enhanced heterogeneously following gadolinium DTPA administration. Transverse plane images with a large enough field of view (FOV) to include both axillae and the vertebral canal were essential, allowing in-slice comparison to detect lesions by asymmetry of structures. Higher resolution, smaller FOV, multiplanar examination of the cervicothoracic spine was important for appreciating nerve root and foraminal involvement. Short tau inversion recovery, T2-weighted, pre and postcontrast T1-weighted pulse sequences were all useful. Contrast enhancement was critical to detecting subtle diffuse nerve sheath involvement or small isointense nodules, and for accurately identifying the full extent of disease. Some canine brachial plexus tumors can be challenging to detect, requiring a rigorous multiplanar multi-pulse sequence MRI examination.
authors.affiliation: Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Fort Collins, CO 80524, USA. skraft@colostate.edu
authors.forename: Susan
authors.initials: S
authors.lastname: Kraft
authors.forename: E J
authors.initials: EJ
authors.lastname: Ehrhart
authors.forename: David
authors.initials: D
authors.lastname: Gall
authors.forename: Lisa
authors.initials: L
authors.lastname: Klopp
authors.forename: Patrick
authors.initials: P
authors.lastname: Gavin
authors.forename: Russ
authors.initials: R
authors.lastname: Tucker
authors.forename: Rod
authors.initials: R
authors.lastname: Bagley
authors.forename: Hege
authors.initials: H
authors.lastname: Kippenes
authors.forename: Constance
authors.initials: C
authors.lastname: DeHaan
authors.forename: Vince
authors.initials: V
authors.lastname: Pedroia
authors.forename: Beth
authors.initials: B
authors.lastname: Partington
authors.forename: Natasha
authors.initials: N
authors.lastname: Olby
mesh_terms: D000818:Animals; D001917:Brachial Plexus; D003120:Colorado; D004283:Dog Diseases / Q000473:pathology*; D004285:Dogs; D005260:Female; D008279:Magnetic Resonance Imaging / Q000662:veterinary*; D008297:Male; D018317:Nerve Sheath Neoplasms / Q000473:pathology / Q000662:veterinary*; D010524:Peripheral Nervous System Neoplasms / Q000473:pathology / Q000662:veterinary*; D011996:Records / Q000662:veterinary; D012189:Retrospective Studies