Intra-arterial versus intra venous contrast-enhanced computed tomography of the equine head

Abstract

BackgroundThe anatomical complexity of the horse’s head limits the abilities of radiography. Computed tomography (CT) in combination with contrast enhanced CT is used more often for diagnosing various head pathology in horses. The objective of this study was to compare intravenous and intra-arterial contrast-enhancement techniques and describe normal and abnormal contrast enhancement in the horse’s head.ResultsAll 24 horses included in the study recovered without complication from the procedures. Compared to the pre-contrast studies, post-contrast studies showed significant contrast enhancement in the pituitary gland (IA: p < 0.0001; IV: p < 0.0001), IA nose septum (p = 0.002), nose mucosa (IA: p < 0.0001; IV: p = 0.02), parotid salivary gland (IA: p < 0.0001; IV p < 0.0001), cerebrum (IA: p < 0.0001; IV: p < 0.0001), rectus capitis muscle (IA: p < 0.0001; IV p = 0.001), IA temporal muscle (p < 0.0001), IA masseter muscle (p <0.0001) and IV brainstem (p = 0.01). No significant contrast enhancement was seen in the eye (IA: p = 0.23; IV p = 0.33), tongue (IA p = 0.2; IV p = 0.57), IA brainstem (p = 0.88), IV nose septum (p = 0.26), IV temporal muscle (p = 0.09) and IV masseter muscle (p = 0.46). Three different categories of abnormal enhancement were detected: a strong vascularised mass, an enhanced rim surrounding an unenhanced structure and an inflamed anatomical structure with abnormal contrast enhancement.ConclusionUsing the intra-arterial technique, similar contrast enhancement is achieved using less contrast medium compared to the intravenous technique. And a potential major advantage of the IA technique is the ability to evaluate lesions that are characterized by increased blood flow. Using the intravenous technique, a symmetrical and homogenous enhancement is achieved, however timing is more crucial and the contrast dosage is more of influence in the IV protocol. And a potential major advantage of the IV technique is the ability to evaluate lesions that are characterized by increased vascular permeability. Knowing the different normal contrast enhancement patterns will facilitate the recognition of abnormal contrast enhancements.

Computed tomography characteristics of equine paranasal sinus cysts

“…A recent study found that all three horses with paranasal sinus cysts given contrast (two with intra‐arterial and one with i.v. protocol) showed cyst wall contrast enhancement . Thus, it is currently not clear if the variable cystic wall enhancement seen in the current study is due to variability in the structure of the cystic wall or in the timing of the post‐contrast acquisition.…”

“…The horses were given 400 mL of 300 mgI/mL i.v. contrast similar to that used in other studies . A recent study found that all three horses with paranasal sinus cysts given contrast (two with intra‐arterial and one with i.v.…”

Application and indications of magnetic resonance imaging and computed tomography of the equine head

“…The use of an intra-arterial route in CT studies allows administration of a low-dose of contrast in a targeted area, which represents less than 50% of the intravenous dose. Studies have shown similar degrees of soft tissue enhancement compared with systemic intravenous administration (Carmalt and Montgomery 2015;Crijns et al 2016). In MRI, different doses have been described in the literature based on empirical experiences (Ferrell et al 2002;Werpy 2007;Judy 2011).…”

“…Studies have shown similar degrees of soft tissue enhancement compared with systemic intravenous administration (Carmalt and Montgomery 2015; Crijns et al . 2016). In MRI, different doses have been described in the literature based on empirical experiences (Ferrell et al .…”

Pituitary gland abscess in a horse subsequent to head trauma

“…; Crijns et al . ), with those suffering from pituitary pars‐intermedia dysfunction (PPID) measuring on average 2.6 ± 0.3 cm rostrocaudal length, 2.4 ± 0.26 cm laterolateral width, and 1.92 ± 0.43 cm dorsoventral height (Kolk et al . ).…”