TABLE 2.

Diagnostic imaging findings in cases (dogs that experienced adverse events) and controls (dogs that did not experience adverse events) with primary brain tumors before (baseline) and after stereotactic brain biopsy

	Cases (n = 8)	Controls (n = 21)	P value
Baseline brain magnetic resonance imaging (MRI) characteristics (%; proportion)
Tumor contrast enhancement
Contrast pattern (all patterns)	Various	Various	.67
No contrast enhancement	12 (1/8)	19 (4/21)	.82
Heterogenous contrast enhancement	0	14 (3/21)	.54
Complete or partial ring enhancement	88 (7/8)	66 (14/21)	.26
Tumor signal characteristics
T2W‐heterogeneity	88 (7/8)	38 (8/21)	.04*
T1W‐hypoinetense	50 (4/8)	71 (15/21)	.39
T1W‐heterogeneity	38 (3/8)	29 (6/21)	.67
Gradient echo signal voids	50 (4/8)	38 (8/21)	.68
Other tumor characteristics
Peri‐tumoral edema	100 (8/8)	81 (17/21)	.55
Frontal location	38 (3/8)	29 (6/21)	.67
Parietal location	25 (2/8)	24 (5/21)	1.00
Temporal location	25 (2/8)	14 (3/21)	.60
Piriform location	12 (1/8)	33 (7/21)	.38
Spherical or ovoid shape	38 (3/8)	57 (12/21)	.43
Intratumoral fluid	12 (1/8)	9 (2/21)	1.00
Features of mass effect
Distortion of lateral ventricle	100 (8/8)	61 (13/21)	.066
Abuts ventricle	75 (6/8)	71 (15/21)	1.00
Falcine herniation or midline shift > 3 mm	25 (2/8)	29 (6/21)	1.00
Transtentorial herniation	37.5 (3/8)	38 (8/21)	1.00
Foramen magnum herniation	25 (2/8)	24 (5/21)	1.00
Postbiopsy imaging findings (%; proportion)
Intracranial hemorrhage	88 (7/8)	52 (11/21)	.08
Pneumocephalus	12 (1/8)	19 (4/21)	.67

^*Statistically significant, P < .05.