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.
