Page 367 - Feline diagnostic imaging

22.6 nterrentional rocedures 375

(b) (d)
(a)

(c)

Figure 22.29 Radiography of megacolon. (a) Lateral projection of a 13-year-old castrated male domestic shorthair with a history of
obstipation. The colon is distended with fecaloid material that is more opaque than usual, suggesting that it is dessicated. (b)
Ventrodorsal projection. (c) Lateral projection of another cat with megacolon – a 9-year-old castrated male domestic shorthair with
a history of chronic weight loss and diarrhea. The colon was distended, with the length to L5 being 1.6. Gas and unformed fecaloid
material fill the colon. (d) Ventrodorsal projection.

altered wall layering. The affected portion of intestine can 22.6 Interventional Procedures
be identified by connecting it to normal intestine.
Hypoechoic‐to‐anechoic micronodules with a diameter Gastrointestinal masses or thickened walls can be
of 1–3 mm have been reported in the colonic submucosa of sampled using ultrasound‐guided aspiration or biopsy
14 cats and 42 dogs, most of whom had diarrhea as the (Figures 22.16j, 22.19c, 22.28d, and 22.32). Aspirates can be
main clinical sign. Almost half of the cats had enlarged obtained using a 20 or 22 gauge needle and an attached
abdominal lymph nodes and two‐thirds had changes in the syringe [56]. In very thick walls or masses, we have also
small intestine, including loss of wall layering or thicken- had success using a “woodpecker” technique after insert-
ing. Some had free abdominal fluid. Histopathology at nec- ing the needle into the wall/mass. The needle is moved rap-
ropsy of one cat showed lymphatic follicles within the idly up and down while taking care to stay within the wall.
submucosa and infiltration of lymphocytes and plasma Biopsies can be obtained using standard biopsy instru-
cells into the submucosa. The lesions resolved in some ani- ments. Both aspirates and biopsies have been shown to be
mals but persisted in others and were thought to represent safe procedures but the accuracy of results is better for
inflammatory change [55]. malignant lesions compared to those that are benign [57].