Page 406 - Feline diagnostic imaging

24.6 ­Diseisi of tsf eancsei 415
for detection of moderate to severe pancreatitis, and able the pancreas was considered altered in five cats 3/5 were
to discriminate normal cats with 88% specificity [9]. In a hypoechoic and 2/5 had a coarse echotexture [16].
later study in one cat, radiolabeled leukocytes and CT
were used to evaluate for pancreatitis. Initial normal activ- 24.6.3 Pancreatic Masses/Neoplasia
ity was seen in the lung, liver, and spleen followed by peak
activity in the pancreas noted four hours after administra- 24.6.3.1 Radiographic/Ultrasonographic Imaging
tion of radiolabeled leukocytes. On the precontrast images, Multiple nodular changes in the pancreas can be found in
CT showed an enlarged heterogeneous pancreas. On post- older patients as an incidental finding. Multiple hypo-
contrast CT images, the pancreas began hyperattenuating echoic nodules are typically associated with hyperplasia,
10 minutes post injection. Histologic confirmation of but neoplasia cannot be ruled out. Pancreatic primary
moderate to severe pancreatitis was found on surgical neoplasia is rare, with adenocarcinoma being the most
biopsy of the pancreas [14]. common. One study of 19 cats, 14 with pancreatic neopla-
sia and five with nodular hyperplasia, showed radio-
24.6.1.5 Magnetic Resonance Imaging (MRI)/ graphic evidence of a mass effect present in 6/6 cats
Magnetic Resonance Cholangiopancreatography imaged with neoplasia and 3/3 cats imaged with nodular
Magnetic resonance imaging has been found to be more hyperplasia. Radiographic loss of abdominal detail was
sensitive in human medicine for detection of subtle changes noted in 4/6 cats imaged with neoplasia. Ultrasonographic
associated with pancreatic disease than ultrasound. In a findings in eight cats imaged showed an overlap in find-
study on cats with pancreatitis [15], mild to moderate ings such as an increase in pancreatic width, lymphade-
enlargement of the pancreas was noted on MRI, which was nopathy, and abdominal effusion. Pancreatic neoplastic
similar to the ultrasound findings in the same group using nodules were hypoechoic in 7/8 and mixed in 1/8 cats.
>1.0 cm as abnormal. In this study, signal alteration on Nodules were hypoechoic in all cats in the hyperplasia
MRI was found in 9/10 cats with pancreatitis. When com- group (5/5). There was a tendency for cats with a neoplas-
pared to the liver, the pancreas prior to contrast adminis- tic process to have a single nodule that was larger in size
tration appeared hypointense on T1‐weighted images and (>2.0 cm) than cats with nodular changes (Figures 24.24–
hyperintense on T2‐weighted images in cats with pancrea- 24.30). The nodular changes appeared to be smaller and
titis. In the normal cats, prior to contrast administration, more numerous than the neoplastic process (Figures 24.31–
the pancreas appeared hyperintense on T1‐weighted 24.33). However, overlap in these findings was demon-
images and hypointense or isointense on T2‐weighted strated, requiring cytology or histopathology to determine
images. Contrast enhancement of the pancreas was similar the final diagnosis [17].
to normal cats with mild homogeneous enhancement. On In a separate study of 34 cats with exocrine pancreatic
MRI and ultrasound, the pancreatic duct was dilated in carcinoma, the typical presentation was for weight loss
most cats with pancreatitis. Although this finding can be a and decreased appetite. Paraneoplastic dermatologic syn-
normal aging change, other studies suggest that atrophy of drome has been reported with pancreatic or biliary carci-
the pancreas secondary to chronic disease causes traction noma, presenting with a nonpruritic symmetric alopecia
of the duct followed by dilation [15]. on head, limbs, and ventrum. Only 3/23 cats imaged had
pulmonary nodules on thoracic images; 2/3 had diffuse
nodules and 1/3 had a single nodule. In 16/34 cats that
24.6.2 Pancreaticolithiasis
had abdominal radiographic imaging, four were consid-
Mineralization within the pancreatic duct can be seen ered normal, six showed loss of abdominal detail, six had
alone or in association with mineralization of the biliary a cranial abdominal mass effect, and two had hepatomeg-
system within the liver parenchyma or gallbladder stones aly. Abdominal ultrasound was performed in 33/34 cats
(choleliths) (Figures 24.22 and 24.23). Mineralization and all but one showed nodular pancreatic changes.
within the pancreatic duct may lead to partial or complete Abdominal effusion was seen in 16/33, liver abnormalities
obstruction. Obstruction of the CBD (>5 mm) was exam- in 12/33, splenic nodules in 2/33, lymphadenopathy in
ined in 30 cats – 12 with neoplasia, 11 with inflammation, 11/33, reactive fat in 3/33, and bile duct dilation in 2/33.
and seven with choleliths. Interestingly, dilation of the The pancreatic nodules ranged from 1.5 to 6.0 cm in size.
gallbladder was present in <50% of these cases. The pan- In this study, 5/34 cats were diabetic. Survival rates were
creas was identified in 19/30 cats and considered thick- better in cats undergoing surgical removal of the pancre-
ened in 12/19. The distribution of a thickened pancreas atic nodule than in those that only had an aspirate or exci-
was 2/12 from the neoplastic group, 7/12 with inflamma- sional biopsy. Average survival time in cats with this tumor
tion, and 3/12 in the cholelith group. The echogenicity of type was only 97.5 days [18].