Usefulness of a half-fourier acquisition single-shot turbo spin-echo pulse sequence in identifying arachnoid diverticula in dogs.
ABSTRACT Single-shot turbo spin-echo sequences are heavily T2-weighted sequences that are exceptionally well suited to evaluate the subarachnoid space. In the T2-weighted fast spin-echo sequences that are used routinely in spinal magnetic resonance (MR) imaging, the subarachnoid space is not well differentiated from the surrounding epidural fat, which could lead to decreased detection of lesions of the subarachnoid space such as arachnoid diverticula. Our purpose was to determine the added value of a single-shot turbo spin-echo sequence in identifying cystic lesions of the subarachnoid space in dogs. MR images of six dogs with a confirmed arachnoid diverticulum and 24 dogs with other spinal disease were included. Six observers were asked to interpret only T2-weighted images initially, and in a second session, T2-weighted and half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences. The MR images were anonymized, and no signalment, history, or clinical information was provided. Without the HASTE sequences, 25% of arachnoid diverticula were identified. Adding the HASTE sequence increased the diagnosis of arachnoid diverticulum to 52.8%. The resulting difference, after adding the HASTE sequence, of 27.8% was statistically significant (P = 0.002). No false-positive diagnoses of arachnoid diverticulum were made with either sequence. Although sensitivity in this study was likely artificially low, the significantly increased detection rate of arachnoid diverticula when using HASTE imaging indicates that this sequence is a valuable addition to MR imaging protocols for the canine spine.
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ABSTRACT: Clinical features, myelography, and computed tomography imaging findings as well as neurological outcome with and without surgery in 5 pug dogs with thoracolumbar arachnoid diverticula are described. Short-term prognosis after surgical therapy may not be as good as reported for other canine breeds, since immediate postsurgical deterioration is possible. Improvement of neurological deficits beyond the presurgical status may take several months.The Canadian veterinary journal. La revue veterinaire canadienne 10/2013; 54(10):969-73. · 0.47 Impact Factor
Article: Extramedullary Spinal Cysts in Dogs[Show abstract] [Hide abstract]
ABSTRACT: Objective To (1) synthesize the terminology used to classify extramedullary spinal cysts in dogs to clarify some of the commonly reported misconceptions, and (2) propose a classification scheme to limit confusion with terminology.Study designLiterature review.Methods An online bibliographic search was performed in January 2013 for articles relating to extramedullary spinal cysts in dogs using PubMed (http://www.pubmed.gov/) and Google Scholar (http://scholar.google.com/) databases. Only peer-reviewed clinical literature describing cystic lesions pertaining to the spinal cord and associated structures was included.ResultsFrom 1962 to 2013, 42 articles were identified; 25 (95 dogs) reported meningeal cysts, 10 (24 dogs) described 60 extradural cysts, 3 reports (18 dogs) described discal cysts or acute compressive hydrated nucleus pulposus extrusions (HNPE). Spinal cysts were categorized by location based on cross-sectional imaging as meningeal or extradural non-meningeal. Sub-classification was then performed based on surgical findings and pathology. Meningeal cysts included arachnoid diverticulae and Tarlov (perineural) cysts. Extradural non-meningeal cysts included intraspinal cysts of the vertebral joints, ligaments and discs. Discal cysts also fit this category and have been reported extensively in humans but appear rare in dogs.Conclusions Extramedullary spinal cysts should be first classified according to location with a sub-classification according to pathologic and surgical findings. Previous canine cases of discal cysts appear to represent a different disease entity and the term acute compressive HNPE is therefore preferred.Veterinary Surgery 05/2014; DOI:10.1111/j.1532-950X.2014.12200.x · 0.99 Impact Factor
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ABSTRACT: Intracranial arachnoid diverticula (cysts) are rare accumulations of cerebrospinal fluid (CSF) within the arachnoid membrane. The purpose of this retrospective study was to describe magnetic resonance imaging (MRI) characteristics of fourth ventricle arachnoid diverticula in a group of dogs. The hospital's medical records were searched for dogs with MRI studies of the brain and a diagnosis of fourth ventricle arachnoid diverticulum. Clinical characteristics were recorded from medical records and MRI studies were reinterpreted by a board-certified veterinary radiologist. Five pediatric dogs fulfilled inclusion criteria. Clinical signs included cervical hyperaesthesia, obtundation, tetraparesis, and/or central vestibular syndrome. In all five dogs, MRI findings were consistent with obstructive hydrocephalus, based on dilation of all ventricles and compression of the cerebellum and brainstem. All five dogs also had cervical syringohydromyelia, with T2-weighted hyperintensity of the gray matter of the cord adjacent to the syringohydromyelia. A signal void, interpreted as flow disturbance, was observed at the mesencephalic aqueduct in all dogs. Four dogs underwent surgical treatment with occipitalectomy and durotomy. A cystic lesion emerging from the fourth ventricle was detected in all four dogs during surgery and histopathology confirmed the diagnosis of arachnoid diverticula. Three dogs made excellent recovery but deteriorated shortly after surgery and were euthanized. Repeat MRI in two dogs revealed improved hydrocephalus but worsening of the syringohydromyelia. Findings from the current study supported theories that fourth ventricle arachnoid diverticula are secondary to partial obstruction of the central canal or lateral apertures and that arachnoid diverticula are developmental lesions in dogs.Veterinary Radiology & Ultrasound 11/2014; 56(2). DOI:10.1111/vru.12218 · 1.26 Impact Factor