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Questions Asked at the HR5th (SR5th) Bonus Viewa
Is there any free fluid in the abdominal (peritoneal) cavity?	Yes or no
How much free fluid is at the HR5th (SR5th) bonus view using the AFAST‐applied fluid scoring system?a	0, 1/2, 1NOT part of the abdominal fluid scoring system
Is there any free fluid in the retroperitoneal space?	Yes or noTrivial, mild, moderate, severe (also can measure and record its greatest dimension)
What does the right (#left) kidney look like?b	Unremarkable or abnormal
What does the liver (#spleen) look like?b	Unremarkable or abnormal
Could I be misinterpreting an artifact or pitfall as pathology?	Know pitfalls and artifacts

^a Note that this view is the HR5th bonus view in right lateral recumbency and the SR5th bonus view in left lateral recumbency, often performed with the patient standing after AFAST (and TFAST and Vet BLUE) as the last view performed.

^b It is important to know that the AFAST target organ approach for parenchymal abnormalities is binary as “unremarkable” or “abnormal” to capture the case for additional imaging and confirmatory testing. More interpretative skills may be gained through experience, and additional ultrasound study and training.

Source: Reproduced with permission of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.

The bonus 5th view of AFAST is a bonus in that it is not part of the AFS system; however, it does interrogate the right (or left) retroperitoneal space more thoroughly than the SR (HR) view alone, and assesses the right liver (left liver), and right (left) kidney for soft tissue abnormalities that may otherwise be missed (Figure 6.34).

The HR5th bonus view is imaged by placing the probe at the junction of the costal arch and hypaxial muscles, identical to the SR view but with the probe directed much further cranially because the right kidney is more cranially located and obliquely positioned. In dogs, the right kidney is cupped within the renal fossa of the liver, whereas in cats it is generally separated from the liver by interposing fat (see Figure 6.34). This anatomical feature is important for the sonographer because the canine right kidney is located by following and fanning the right liver caudally and dorsally. If you run out of liver caudally, then you must return to a more craniodorsal acoustic window to find the right kidney. If the costal–hypaxial muscle junction is ineffective for locating the right kidney then the probe may be moved over the 11th and 12th intercostal spaces, although rib shadowing will likely affect the imaging of the right kidney. The left kidney is independent of the liver in both dogs and cats, located more caudally, more parallel to the long axis of your patient, and generally not viewed through intercostal spaces.

Figure 6.32. Examples of typical positive studies at the HRU (SRU) view. In (A) a loop of small intestine that appears like a “hamburger” is wafting in free fluid in real time and easily recognized. In (B) free fluid is outlining what appears to be the spleen. In (C) the spleen is confirmed by the finding of vessels splitting its capsule and free fluid is obvious. In (D) free fluid is seen wafting omentum and small intestine. In (E) an anechoic triangulation is obvious and lastly in (F) an anechoic triangulation, “hourglass like,” is found between loops of small intestine.

Source: Reproduced with permission of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.

Figure 6.33. False positives at the HRU (SRU) view. In (A) and (C) are the abdominal radiograph and the HRU (SRU) view of a patient in which necrotic masses can have intracavitary necrosis with triangulations of fluid mimicking free fluid. Increasing your depth and sliding and sweeping your probe to add more interrogation (or adding a radiograph especially if the AFAST was performed first) is important. If the radiograph was the initial imaging test, AFAST helps differentiate free fluid from a mass or to determine that both are present. By assigning an AFS and performing abdominocentesis, fluid analysis, and cytology, decision making is expedited in most cases. (B) and (D) show an example of pyometra and how the compartmentalization of the uterus may appear like free fluid. The addition of an abdominal radiograph is complementary for best interpreting the AFAST study.

Source: Reproduced with permission of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.

The HR5th bonus view's target organs are the liver and right kidney (or left kidney and head of the spleen).

 The probe should be directed craniodorsal for the HR5th bonus view, and analogously for the SR5th bonus view.

 The author likes to find the liver and then fan through it, sliding caudally because in dogs the right kidney is cupped by the liver in its renal fossa. Thus, if you run out of liver, then you need to restart cranially within the liver again.Figure 6.34. HR5th view on a dog. In (A) two different approaches are shown imaging the HR5th bonus view in which the right kidney and liver are in fact interrogated. In (A) the lateral recumbent method uses the same landmarks as the SR view where the costal arch meets the hypaxial muscles, but the probe is often directed much more cranially because the right kidney in the dog lies further cranially than its left counterpart (in contrast to cats not so much further cranially). The author prefers performing the HR5th bonus view (or SR5th bonus view in left lateral recumbency) with the patient standing after the four views of AFAST, TFAST and Vet BLUE have been completed leaving the HR5th (SR5th) bonus view as the final acoustic window. The same landmarks used in lateral are used in standing. The author avoids imaging between ribs if possible but either approach is acceptable (sonographer preference). In (B) and (C) are unlabeled and labeled CT images to better illustrate the anatomy. In (D) and (E) are typical negative studies of the HR5th bonus view unlabeled and labeled. Use the diaphragm as a landmark to find and follow the liver, which will lead you to the right kidney in dogs. LIV, liver; RK, right kidney.Source: Reproduced with permission of Dr Gregory Lisciandro, Hill Country Veterinary Specialists and FASTVet.com, Spicewood, TX.

 The diaphragm is a good landmark and helps locate the liver since the liver abuts the diaphragm.

 The liver and right kidney are then fanned through, searching for free fluid and screening for soft tissue lesions.