Triple Phase Dynamic Computed Tomographic Perfusion Characteristics of Spirocercosis Induced Esophageal Nodules in Non‐neoplastic Versus Neoplastic Canine Cases

Abstract

Neoplastic transformation of Spirocerca lupi induced esophageal nodules carries a poor prognosis. Clinical, clinicopathological, endoscopic, and radiographic characteristics may be indicative of neoplastic transformation but variable sensitivity and specificity of these parameters makes their use questionable. We hypothesized that CT would be a better diagnostic modality to discriminate between non‐neoplastic and neoplastic nodules. In this prospective study of 38 dogs, the appearance and perfusion characteristics of confirmed spirocercosis‐induced neoplastic and non‐neoplastic esophageal nodules were described using survey CT and triple phase dynamic CT angiography (CTA). Pre‐ and post‐contrast early arterial, late arterial, and venous CTA images were evaluated. Non‐neoplastic nodules were smooth and nonmineralized with a higher proportion of hypoattenuating necropurulent cavities compared to neoplastic nodules that had a more irregular surface, with 93% having mineralized foci and rarely any hypoattenuating pockets. Non‐neoplastic nodules were significantly more perfused than neoplastic nodules with the difference being up to 23 Hounsfield units. The difference was most marked in the early and late arterial phases (P = 0.0005 and 0.00005, respectively). Ratios of the normal esophagus adjacent to the neoplastic and non‐neoplastic nodules did not differ significantly from each other. Perfusion findings demonstrated relative hypoperfusion of the esophageal sarcomas. Findings from the current study indicated that CT characteristics of relative postcontrast hypoperfusion, combined with nodule irregularity and mineralization warrant a high level of concern for neoplastic transformation in canine spirocercosis‐induced esophageal nodules.

Effects of Sedation by Intramuscular Administration of Medetomidine on Canine Abdominal Vascular System and Hepatic Parenchyma Imaging Using Enhancement Dynamic Computed Tomography

“…In veterinary medicine, CT angiography, including dual-phase and triple-phase helical CT, is widely used in clinical and experimental fields [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. In these contrast CT imaging protocols, the timing of the start of scanning was determined based on previously reported TACs [ 13 , 14 , 15 ].…”

“…The arterial phase and portal venous phase are generally scanned within 1 min of the injection of the contrast medium: arterial phase, 15–20 s, and the portal venous phase, 30–40 s after injection. The delayed phase occurs about 2 min after contrast medium injection [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Under the sedation protocol in our study, the AO-EA appeared approximately 30 s after contrast medium injection and the peak AO enhancement about 1 min after injection.…”

“…Therefore, with medetomidine sedation, the contrast effects for the target vascular would not be observed if the CT scan protocol was performed using usual timing of arterial phase and portal phase. This means that, in addition, the contrast enhancement patterns for CT angiography previously described [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ] could not be applied to images obtained under IM medetomidine sedation.…”

“…In veterinary medicine, multiphasic multi-detector computed tomography (CT) angiography, including triple-phase helical CT, is currently used as a diagnostic tool for vascular disorders, such as portosystemic shunts [ 1 ], arteriovenous fistulae [ 2 ], and various tumors [ 3 , 4 , 5 , 6 , 7 , 8 ]. This method is also commonly used for characterizing parenchymal disease, such as pancreatic disease [ 9 , 10 , 11 , 12 ].…”

“…CT imaging further requires that the animal be immobilized, with anesthesia or sedation used to achieve this [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ]. However, agents used for anesthesia and sedation can influence the cardiovascular circulation.…”