Ct‐guided Brain Biopsy Using a Modified Pelorus Mark Iii Stereotactic System: Experience With 50 Dogs

Abstract

This report describes the results of CT-guided stereotactic brain biopsies performed on 50 consecutive dogs using a modified Pelorus Mark III Stereotactic System. Based on available histopathologic samples (stereotactic biopsy [n = 50], surgery [n = 17], necropsy [n = 9]) the patient population consisted of 34 dogs with primary brain tumors, 2 with invasive nasal adenocarcinomas, and 13 with non-neoplastic brain lesions. Brain tissue was not obtained from one dog. In 22 dogs a final diagnosis was made from tissue subsequently obtained from surgical resection or at necropsy. The final diagnosis was in agreement with the stereotactic biopsy diagnosis in 20 of these 22 dogs. In 17 other dogs without follow-up, stereotactic biopsy provided a diagnosis of a specific primary brain tumor subtype. Postoperative complications associated with the biopsy procedure were assessed in 41 dogs. The other 9 dogs either went directly to surgery (n = 7) or were killed (n = 2) immediately after the biopsy procedure. Thirty-six dogs recovered without apparent clinical complications. Postoperative clinical complications in the remaining 5 dogs included transient epistaxis (1 dog), transient exacerbation of cerebellar signs (1 dog), obtundation progressing to coma (1 dog), and medically uncontrollable seizures (2 dogs). The latter 3 dogs with severe neurologic complications all had large primary brain tumors and had been receiving high doses of phenobarbital and glucocorticoids to control seizures at the time of biopsy. These results suggest that this CT-guided biopsy procedure can provide an accurate pathologic diagnosis of brain lesions detected by CT and MR neuroimaging. Further refinement of both technique and case selection is expected to reduce the rate of clinical complications and to improve the accuracy of the procedure.

Placement of Deep Brain Electrodes in the Dog Using the Brainsight Frameless Stereotactic System: A Pilot Feasibility Study

“…In addition, studies have examined image‐guided freehand or directed biopsy techniques, both to biopsy lesions32 and to implant indwelling catheters for delivering brachytherapy 25. Overall, the morbidity and mortality described in most studies in dogs is low, ranging from 12 to 29% and 6 to 9%, respectively 28, 30, 32. This is higher than the 3–12% morbidity rate and 0–1% mortality rate reported in human patients 33, 34.…”

Advances in Diagnostic and Treatment Modalities for Intracranial Tumors

“…Morbidity and mortality associated with brain biopsy vary with the equipment used, experience of the clinician, location of the lesion, and neurologic status of the patient. Early published data described morbidity and mortality rates of 12–27% and 7–9%, respectively 89, 91. At the author's institution, complications generally occur currently in less than 5% of cases with experienced operators, and mortality associated with the procedure is rare.…”

“…Free‐hand, image‐guided, and endoscope‐assisted brain biopsy has been described for dogs84, 85, 86; however, stereotactic‐guided procedures have many advantages. Both CT‐ and MRI‐based stereotactic systems were developed for dogs in the 1980s in the experimental setting,87, 88 and a variety of stereotactic approaches to clinical brain biopsy have been described in dogs and cats, the majority of which have involved CT‐based systems 89, 90, 91, 92, 93, 94, 95. Only 1 commercially available MRI‐based system has been reported,96 that is likely to become a mainstay of stereotactic biopsy in the future.…”

Diagnostic Immunohistochemistry of Canine and Feline Intracalvarial Tumors in the Age of Brain Biopsies

“…Methods currently used for biopsy or excision of brain tumors include stereotactic procedures, 65,86 freehand biopsy with ultrasound guidance, 37,61 endoscopic biopsy, 60 and aspiration. 35 The overall diagnostic yield for stereotactic excisional biopsies in necropsy-confirmed cases can be as high as 95%, 65,86 while methods utilizing freehand techniques have had a yield as low as 25%.…”