Possible Diagnostic problems with ultrasound
|
Explanation and Alternatives
|
| Ectopic Ureter |
In a lot of cases we can find an ectopic ureter with ultrasound, however contrast radiographs, cystoscopy or CT may be needed. |
| Non-dilated obstructed Ureter |
In some cases a non-obstuctive ureteral calculi as well as some obstructive ones may blend into the gas located within the bowel loops. |
| Hepatic Shunts (especially intrahepatic) |
It is possible that ultrasound can have up to a 95% sensitivity when performed by a radiologist or other experienced sonographer. However a CT gives the most information as to the shunt characteristics. Since an ultrasound is questionable on cases for shunt identification and characterization we recommend a CT for definitive diagnosis. |
| GI gas obstructive patterns, GDV and some GI foreign bodies |
Survey radiographs are better to document gas obstructive patterns and GDV. |
| Necrotizing Pancreatitis vs Non-Necrotizing Pancreatitis |
A CT may be better for differentiation between the two and clinical status may help us to determine which is most probable. Also to note is that sonographic appearance may or may not be abnormal is cases of pancreatitis |
| Diaphragmatic hernias (Some) |
Survey radiographs or contrast peritoneography may be needed. |
| Evaluation of liver size |
Ultrasound shows small sections of the liver at any given point therefore an abdominal radiograph will give a better representation of overall liver size. |
| Fetal number |
Abdominal radiograph around day 45 of gestation is usually the most reliable determination due to fetal movement during ultrasound examination. Ultrasound is excellent for determining fetal viability and can help to determine gestational age. |
| Deep thoracic Masses |
Due to the amount air in the chest the ultrasound is unable to get a clear view due to reverberation artifact and refractive artifact from ribs. |
| Diagnosis of Cushing’s/Addison’s |
For hyperadrenocorticism the most important initial criteria is the clinical signs. We like to use ultrasound in conjunction with LDDST and ACTH stim test (our preference is ACTH due to 1 hour duration) to help differentiate pituitary vs tumor. |
| Differentiating IBD vs Intestinal Lymphoma |
In cats biopsies are the only way to definitively to differentiate IBD and Lymphoma. In dogs it can be easier to differentiate with ultrasound, but is best with biopsies. |
