Case: A 21 year old male, who awoke with severe right testicular pain from sleep. A POCUS was promptly performed, which demonstrated the POCUS findings of testicular torsion: lack of vascular flow to the right testicle, with normal flow in the left, consistent with right sided testicular torsion. The testicle's appearance on POCUS was otherwise normal, with no masses seen. There was no cremasteric reflex on the right clinically (Sn 60-70%).

Urology was called, and a scrotal ultrasound requested from radiology, but as it was Sunday there were 12 other urgent scans were pending, with only one tech on duty. Urology came promptly, and looked at the POCUS findings. The urology resident immediately manually de-torted the testicle, and asked if the ER physician could confirm flow by POCUS. This was performed, and flow was verified. The patient was also significantly more comfortable, and a confirmation ultrasound was performed by radiology a couple of hours later.

The bonus of POCUS: the diagnosis was made immediately, and flow was immediately confirmed following detorsion. An "A" case on a weekend during a pandemic became a case appropriate for outpatient follow up, for elective orchiopexy.

POCUS for the diagnosis of testicular torsion in children and young adults with acute scrotum has a sensitivity of 100%, and a specificity of 99.1% when performed by emergency physicians (Friedman et. al, 2019).

How to do this:

Draping and positioning and communication are very important with ultrasound of the testes. Position the patient semi-recumbent, with a towel or gown rolled under the scrotum to elevate the testes, and drap to only expose the testes, with the penis covered on the abdomen.

First, inspect both testes for normal appearance (tissue heterogeneity, and whether there is any hydrocele).

Then turn on "colour doppler" over the unaffected testicle, and adjust the scale to show vascular flow. Then place the transducer with the same settings over the painful testicle, and if reduced or absent flow is demonstrated, the diagnosis is made.

Ideally, save a clip of both testes side by side demonstrating a lack of flow in the affected side.

C. Heslop

Case: A 75 year old female presents with a sudden onset of generalized abdominal pain for 1 day. You perform a AAA scan using the abdominal probe. You have some difficulty because of bowel gas. 1. What are some strategies to help you obtain a determinate image? Ultimately, you’re able to generate these images. 2. Provide your interpretation of the images.

Answer: In the face of a challenging examination for AAA, it’s often bowel gas that’s in the way. Slow down and apply firm downward pressure for at least 5 seconds in sone spot - often this is enough to get bowel and gas “out of the way” and give you a view. Another way to negotiate an indeterminate image, is to slide off the midline to the patient’s right and heel towards the midline - this can help you view the aorta from a more lateral approach. This image shows a large 5 cm aortic aneurysm. Remember a positive scan is >=3 cm. Remember the aorta should be measured from “wall to wall” - not just the lumen. See image.

Take home: Pressure and going off the midline can help you negotitate an indeterminate AAA scan. Abnormal is >=3 cm. Measure wall to wall.

C. Heslop / D. Cho

Case: A 33 year old male presents with sudden severe central and right sided chest pain, worse with inspiration, also worse with any movements. His pain was very severe; he rates it 8/10 (and indeed he looks truly uncomfortable). He has a history of pericarditis at age 18, but his father died at 40 of an MI. He quit smoking last year, and is otherwise healthy, and uses no recreational drugs. The ECG is normal, and bloodwork is pending. You note his respiratory rate of 22 and given the pleuritic nature of his pain, and his history, you take a look with POCUS, both to evaluate for pericardial effusion (?pericarditis) and for echocardiographic signs for PE (click links for Pocus Atlas examples) When you take a look at his heart in the parasternal long axis view, you see the following still image clip (click here for video). The LV function appears to be normal, but inferior to the LV, there is a hypo-echoic area suggestive of a possible pericardial effusion. How can you verify this is a pericardial effusion? What other views or techniques could you use, and what other anatomical structures are important to assess?

Answer: When evaluating for a pericardial effusion on a parasternal long axis view, it is essential to identify the descending aorta. A true pericardial effusion will exist as a hypoechoic strip anterior (or near-field) to the descending aorta. The best (most accurate) view for assessing for pericardial effusion is the subxiphoid view. When posteriorly - this will help distinguish epicardial fat from a bonafide effusion - epicardial fat will disappear as you sweep posteriorly while pericardial effusions will increase in size.

C. Heslop / D. Cho

Case: A 54 year old female presents with RUQ pain and nausea. You scan her RUQ to look for gallstones, and you see this bright, echogenic structure. You think this looks like a gallbladder WES (wall-echo-shadow) sign, where the gallbladder is collapsed and full of stones - you see the gallbladder wall, the highly echogenic (bright) surface of the gallstones, and the solid shadows cast from them. This is a highly worrisome finding as it implies that the gallbladder is full of stones and, in the right clinical setting, would make you worried about cholecystitis. This image was submitted for QA. On review, a QA flag was raised. How can you be sure that this is the gallbladder?

Answer: The first principle for the gallbladder scan is to the place the probe longitudinally (probe marker facing the cephalad) in the subxiphoid region, and laterally along the right subcostal border until the kidney is visualized. The area of interest is the most anterior cystic (fluid-filled) structure. Lateral to the original image, you come across the image on the left. The patient is most tender over this structure, with a positive sonographic Murphy’s sign. You can see a fluid-filled, distended gallbladder with two stones in the neck. The patient was diagnosed with cholecystitis.

Take home: When looking for the gallbladder, remember to always perform the full subcostal slide until you see the kidney. The most anterior cystic structure should be the gallbladder. Sometimes it will only be visible in the laterally (away from the midline).

C. Acton

Case: 95 F trips over the threshold at her hair salon and lands on outstretched right hand. She comes to your ER where a colles (distal radius) fracture is diagnosed. It is obvious clinically and radiographically. You note that the fracture is extremely comminuted and there is significant shortening and dorsal angulation. She has multiple medical comorbidities and is a higher risk sedation. A medical student attempts the reduction. You place a linear (high frequency) probe longitudinally (parallel) to the distal radius along the dorsum of the wrist and this is what you see. Has this fracture been properly reduced? The sedation doc asks, "do you need to pull again?"

Answer: The answer is YES. The reduction is incomplete. You still see significant dorsal angulation. You kindly ask for continued sedation. More consistent traction is applied and the fracture is reduced again. Post reduction POCUS shows correction and smoothing out of the dorsally angulated fragment. Check out this quick EM POCUS Cases review (8 mins).

Take home: Intra-procedure POCUS assessment of fracture reduction may help increase the chance of a satisfactory reduction and prevent the need to re-sedate.

D. Cho

Case: A 24 F presents with severe abdominal pain. Blood pressure is 70/40 and HR is 130. You learn that a home pregnancy test was “positive” last week. You perform a FAST exam and examine the right upper quadrant. Is there free fluid? What maneuvre could you perform to maximize the sensitivity of this exam?

Answer: Let's get back to the basics. We are worried about a ruptured ectopic and free fluid in the abdomen would help clinch the diagnosis. Recall that in the supine patient, the paracolic gutters force free fluid (i.e. blood in this case) into Morrison's pouch or the hepatorenal interface. Also recall that the caudal tip of the liver is critical to visualize as this is where fluid will first accumulate. Here's a case where there is nothing to appreciate along the medial and lateral part of the hepatorenal interface - but look at the caudal tip. We see a pocket of fluid - that's blood! This is a positive FAST examination. To maximize sensitivity, place the patient in Trendelenberg (head-down) position for at least 5 minutes. Good tip if you really want to be sure.

Take home: remember the basics for your fast exam. 1) the patient must be supine; 2) placing them head-down will increase your sensitivity; 3) the caudal tip of the liver in the RUQ must be visualized.

D. Cho

Case: A 87 F presents with shortness of breath. As part of your assessment, you perform a focused exam of the patient’s lungs and assess for B-lines. The patient is lying in recumbent position. You scan the lung systemically in four different quadrants per hemithorax “looking for B lines". The lungs demonstrate no B-lines except for this image seen in the left lower lobe. What is the differential of this finding?

Answer: Not all b-lines = pulmonary edema. The distribution and the laterality of B lines (i.e. where you find B lines in the chest) determines the differential. The differential for unilateral, focal B lines is: pneumonia, pulmonary contusion, pulmonary hemorrhage, pulmonary infarct. This is in contrast to diffuse, often bilateral B lines whose differential includes: ARDS, pulmonary edema, pulmonary fibrosis, bilateral pneumonia. The key point is be methodical about scanning the thorax. We recommend a five-region technique according to the diagram - 4 quadrants per hemithorax + the posterior longitudinal view to look focr a pleural effusion. This systematic method searching for B-lines can help inform the differential. A more extensive discussion of B lines is available here.

Take home: It is not enough to scan a single region in the lungs. B lines that are bilateral and diffuse can suggest pulmonary edema - in the right clinical context!

D. Cho

Case: A 55 F presents with acute onset of R sided flank pain radiating into the groin. They have a history of renal colic and this presentation is identical to their prior presentations. You perform renal POCUS. What is the relevant finding? Assuming their creatinine is normal and urine dip is not infected, do you order a CT or KUB xray or comprehensive ultrasound? Potential answers coming up next month.

Answer: The finding is moderate hydronephrosis - notice the dilation of the renal calyces. Look to the left for a reminder of what mild (middle image) and severe hydronephrosis (bottom image) looks like - remember, it’s a continuum. To put it simply - the more black you see inside the kidney, the worse the hydro is.

A recent meta-analysis suggested that the finding of moderate to severe hydronephrosis with a consistent clinical picture for renal colic (history, physical exam and lab work) is highly specific for the presence of a stone (94.4%). The absence of any degree of hydronephrosis cannot exclude the diagnosis, however. A recent QI project completed by Adrian Wu (PGY5) at Sunnybrook demonstrated some impressive results when using POCUS on patients < 50 years old with a history of renal colic presenting with symptoms compatible with renal colic: ~50% of the group used renal POCUS, 1h34m LOS reduction, 50% reduction in CT usage, 18.75% return visits (all for pain, no alternative diagnoses) which was consistent with the overall 20% return rate for kidney stones regardless of imaging modality.

Take home: does your patient with who presents with a clinical picture of renal colic who also has hydronephrosis on POCUS need other imaging? Perhaps not.

D. Cho

Case: A 63 M presents with near complete visual loss with a dark curtain in the L eye. What is the ultrasound finding and how can we differentiate it from a common mimicker and common source of disdain from ophthalmologists who claim we “overcall" the ultrasound too often.

Answer: About half of respondents thought this was a retinal detachment - the other half thought it was PVD. This is one reason why ophthalmologists are somewhat skeptical about our ability to use POCUS to define who has RD vs PVD. This is a very clear example of a retinal detachment. Why is it a retinal detachment (top image): 1) it is extremely bright (hyperechoic). Even on this relatively “low” gain setting it is a bright and thick line that is hard to miss. 2) it is clearly tethered to the optic nerve (a key feature for RD). 3) It demonstrates few “after movements” - ocular ultrasound is a dynamic assessment. You must have the patient actually move their eyes left/right and up/down. Compare and contrast the original image to an example of a PVD (middle image). Note the following: 1) It’s much less hyperechoic and much thinner/finer. 2) it is NOT tethered to the optic nerve. 3) It demonstrates lots of after movements - it swishes around in a more carefree manner on eye movement. One tip to distinguish - if you don’t see much on a regular gain setting, try setting the gain to 100% - this “high gain” setting often highlights the subtle PVD and/or retinal hemorrhage (third image).

Take home: PVDs are subtle. RDs are not. Both clinically and on ultrasound.

D. Cho

Case: A 43 F presents with acute onset shortness of breath. She is tachycardic and hypotensive. What is the relevant POCUS finding (ignoring the pericardial effusion).

Answer: This image is of the so-called D-sign. The parasternal short axis view demonstrates the RV on screen left and the LV on screen right. During systole, you can see flattening of the interventricular septum. This can be a sign of high right-sided pressures. PE if it’s acute or chronic causes like pulmonary fibrosis as well.

Take home: The D sign does NOT equal PE. Clinical correlation is required.

D. Cho