A magnetic resonance imaging-based classification system for indication of trans-sphenoidal hypophysectomy in canine pituitary-dependent hypercortisolism.
OBJECTIVE
The objectives of this study were to establish a magnetic resonance imaging-based classification system for canine hyperadrenocorticism according to pituitary gland extension, determine indications for trans-sphenoidal hypophysectomy, and clarify the prognosis for each disease grade.


METHODS
A 5-point classification system (Grades 1 to 5) was developed based on tumour extension in dorsal and cranio-caudal directions. Cases were then classified as Type A: no arterial circle of Willis or cavernous sinus involvement and Type B: cases in which these blood vessels were involved.


RESULTS
Medical records and magnetic resonance imaging data of 37 cases with hyperadrenocorticism were reviewed. Thirty-three cases underwent surgery; 4 Grade 5 cases did not have appropriate indications for surgery, and other therapies were used. Complete resection was achieved for 3, 3, 22 and 1 Grade 1A, 2A, 3A and 3B cases, respectively. Resection was incomplete in 1, 1 and 2 Grade 3A, 3B and 4B cases, respectively. Remission was achieved in 29 cases. Recurrence occurred in 4 cases, all of which were classified as Grade 3.


CONCLUSIONS
Dogs with Type A, Grade 1 to 3 hyperadrenocorticism had a good prognosis following trans-sphenoidal hypophysectomy. Grade 3B, 4 and 5 cases may not be suitable for this surgery.
Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Tokyo, 180-8602, Japan.
A
A
Sato
Division of Veterinary Internal Medicine, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Tokyo, 180-8602, Japan.
T
T
Teshima
Laboratory of Small Animal Surgery 1, School of Veterinary Medicine, Kitasato University, 35-1 Higashi23ban-cho, Aomori, 034-8628, Japan.
H
H
Ishino
Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Tokyo, 180-8602, Japan.
Y
Y
Harada
Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Tokyo, 180-8602, Japan.
T
T
Yogo
Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Tokyo, 180-8602, Japan.
N
N
Kanno
Division of Veterinary Radiology, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Tokyo, 180-8602, Japan.
D
D
Hasegawa
Division of Veterinary Surgery, Department of Veterinary Science, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Tokyo, 180-8602, Japan.
Y
Y
Hara
D000236:Adenoma / Q000145:classification / Q000000981:diagnostic imaging / Q000601:surgery / Q000662:veterinary*; D000308:Adrenocortical Hyperfunction / Q000145:classification / Q000601:surgery / Q000662:veterinary*; D000818:Animals; D004283:Dog Diseases / Q000145:classification* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D004285:Dogs; D005260:Female; D007016:Hypophysectomy / Q000662:veterinary*; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000662:veterinary*; D008297:Male; D060787:Neoplasm Grading / Q000379:methods / Q000662:veterinary*; D047748:Pituitary ACTH Hypersecretion / Q000662:veterinary; D010902:Pituitary Gland / Q000000981:diagnostic imaging / Q000473:pathology; D010911:Pituitary Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies