Читать книгу Point-of-Care Ultrasound Techniques for the Small Animal Practitioner - Группа авторов - Страница 275

 Normal echogenicity rule of thumb. The spleen (S) is more echogenic (hyperechoic, brighter) than the liver (Li), which is the same or slightly more echogenic (hyperechic, brighter) than the cortex of the kidney (CK). Remember this as S > Li ≥ CK or the mnemonic “SLiCK” for dogs. For the feline, hepatic echogenicity is often compared to the adjacent falciform fat and the feline liver should be isoechoic to slightly hypoechoic to the falciform fat.

 Benign conditions may appear ultrasonographically “malignant.” Hepatic echogenicity can be difficult to interpret and significant liver disease may still be present even with an unremarkable exam. Ultimately, tissue sampling is necessary for definitive diagnosis of hepatic parenchymal diseases.

 Be familiar with the possible artifacts related to the liver and gallbladder. The fluid‐filled gallbladder is subject to several artifacts including side‐lobe, edge shadowing, and far‐field acoustic enhancement. A mirror image artifact of the gallbladder and liver may appear on the thoracic side of the diaphragm due to the air interface between the diaphragm and lung, and can be mistaken for diaphragmatic hernia, pleural and pericardial effusion.

 The origin of a large midabdominal mass can sometimes be difficult to determine when the mass contacts multiple origins. In this case, try repositioning the patient from dorsal to lateral recumbency. This will often separate the liver and spleen from one another and help determine the origin of the mass.

  Always look into the thorax through the diaphragmatic hepatic interface when evaluating liver to investigate the pleural and pericardial spaces, and the lung surface along the diaphragm.

 An AFAST and assignment of an abdominal fluid score should be considered as routine for POCUS liver and gallbladder examinations and the Global FAST approach should be performed so as not to miss comorbidities including intraabdominal bleeding or peritonitis as well as intrathoracic conditions. The AFAST and its fluid scoring system should be used on initial patient evaluation and also to monitor for complications such as hemorrhage or peritonitis after interventional procedures including liver and gallbladder surgeries, percutaneous aspirates and biopsies, and laparoscopic procedures. The Global FAST approach is used for postinterventional intrathoracic complications including aspiration pneumonia (see Chapters 23 and 36).