Percutaneous translumbar spinal cord compression injury in dogs from an angioplasty balloon: MR and histopathologic changes with balloon sizes and compression times.
OBJECTIVE
Our previous model of spinal cord injury (SCI) included six dogs undergoing 30-minute compression with a balloon in the subarachnoid space. We determined whether various balloon sizes and compression times creates a gradation of injuries.


METHODS
In 17 dogs (including our original six), angioplasty balloons 2, 4, or 7 mm in diameter (2 cm long) were inflated at T6 for 30, 120, or 240 minutes. T1- and T2-weighted, gadolinium-enhanced, and short-tau inversion recovery (STIR) MR images were obtained at 1.5 T. Spinal canal occlusion (SCO) was measured as balloon area-spinal cord area. Hematoxylin-eosin and beta amyloid precursor protein staining were performed to demonstrate hemorrhage and axonal injury, respectively. Injuries were scored as mild, moderate, or severe. Trends were assessed with one-way analysis of variance.


RESULTS
SCO was 12.5-20% for 2-mm balloons, 28-56% for 4 mm, and 62-82% for 7 mm. No abnormalities were seen with SCO <30%. T1- and T2-weighted images had the poorest diagnostic performance; STIR images were best for predicting hemorrhage and axonal injury. Hemorrhage was demonstrated more frequently than was axonal injury. SCO (P < .0001) and hemorrhage (P = .002) significantly increased with balloon size. Longer inflation times tended to increase injuries for a given size, but differences were not significant.


CONCLUSIONS
Compression injuries depended on the level of SCO. The compression times tested had less effect than the degree of compression. The value of 1.5-T MR imaging varied with the sequence and improved with contrast enhancement. STIR images showed SCIs not otherwise detected.
Purdy
Phillip D
PD
Department of Radiology, Division of Neuroradiology, the University of Texas Southwestern Medical Center at Dallas 75390-8896, USA.
White
Charles L
CL
Baer
Donna L
DL
Frawley
William H
WH
Reichard
R Ross
RR
Pride
G Lee
GL
Adams
Christina
C
Miller
Susan
S
Hladik
Christa L
CL
Yetkin
Zerrin
Z
D000800:Angioplasty, Balloon / Q000009:adverse effects* / Q000295:instrumentation; D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D004285:Dogs; D004867:Equipment Design; D008279:Magnetic Resonance Imaging; D008297:Male; D012720:Severity of Illness Index; D013117:Spinal Cord Compression / Q000175:diagnosis* / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D013194:Staining and Labeling
D003287:Contrast Media