VOTW: Thoracic Aortic Aneurysm

This week’s VOTW is brought to you by Dr. Ye, Dr. J Yang and Dr. Quinn!

A 58 year old male presented to the ED after fall. He was tachycardic to 120s, febrile and diagnosed with Flu A as well as alcohol withdrawal. He had an elevated troponin for which a POCUS was performed which showed…

Clip 1 shows a parasternal long axis view of the heart with multiple findings. First there is a pericardial effusion with possible RV collapse during systole concerning for tamponade. There is also a large, ovular, immobile, structure approximately 7cm in diameter where the left atrium should be. Based on our knowledge of anatomy, the differential includes dilated fluid-filled esophagus or thoracic aortic aneurysm.

The answer was found on CT chest to be a 7cm x 6cm descending thoracic aortic aneurysm (TAA) with a intra-aneurysmal thrombus with marked mass effect on the left atrium (CT image below).

Since Dr. Danta already did a wonderful VOTW on cardiac tamponade, this weeks’ topic is the thoracic aorta!

POCUS for the thoracic aorta

We can evaluate the thoracic aorta on POCUS for aneurysm or dissection. Unlike the abodminal aorta, we can only visualize certain snippets of the thoracic aorta. This results in a lower sensitivity (67-90%) (1) and cannot be used as rule out test for dissection.

Best views for visualizing the thoracic aorta

1. Parasternal long view  – Aortic root, proximal ascending aorta, portion of descending aorta

2. Supra-sternal notch view – Aortic arch (here's a good video on how to get this view: https://www.youtube.com/watch?v=gv6yZNOIchE)

3. Parasternal short view - depending on your angle, you can sometimes see the descending aorta in its long axis

Normal diameter measurements

Thoracic aorta < 4cm (remember FOUR-acic aorta)

Abdominal aorta < 3cm

Iliac arteries < 1.5cm

Pearls

• Measure the aortic root distal to the sinus of valsalva from leading edge to leading edge.

•  The RV, aortic root, LA should appear 1:1:1 in size in the parasternal long view. If the ascending aorta looks larger than the LA or RV, this would be concerning for an aneurysm.

• Increase your depth on the parasternal long to include the descending aorta posterior to the left atrium. You might catch a descending thoracic aortic aneurysm or dissection and the descending aorta also helps differentiate pericardial vs pleural effusion.

Back to the patient

Both vascular surgery and cardiothoracic surgery were consulted for this patient during admission but he remained too sick from his medical illnesses that he was not deemed a candidate for surgical intervention.

References

1. Fengju Liu, Lianjun Huang. Usefulness of ultrasound in the management of aortic dissection. Rev. Cardiovasc. Med. 2018, 19(3), 103–109.

Happy scanning,

Your Sono team

VOTW: Biceps Tendinitis

Hi all,

This week’s VOTW is brought to you by Dr. Evans!

A 56 year old male presented with dull left shoulder pain for two days. He denied any trauma, swelling, erythema to the area or fevers. He did endorse repetitive lifting motions at work. The exam was unremarkable except for some pain w/ ROM of the shoulder. A POCUS showed…

In Clip 1, the long head of the biceps tendon is seen in the bicipital groove (between the greater and lesser tuberosity) in its short-axis surrounded by a rim of hypoechoic fluid. 

Clip 2 shows the biceps tendon in its long-axis, again surrounded by a small amount of hypoechoic fluid. This is consistent with biceps tendinitis. The tendon itself appears intact without tears. The patient was discharged with NSAIDs and ortho follow up.

POCUS Shoulder Exam

We have all had patients presenting with non-traumatic shoulder pain. They get their therapeutic x-ray and you tell them to try NSAIDs and follow up with ortho.

While the POCUS shoulder exam may not be life-saving, it has the potential to quickly provide the diagnosis for a range of pathologies. Finding the answer to the patient's pain may might result in a more satisfied patient 😊. The hard part is learning and remembering this multi-step exam.

Evaluting the long head of the biceps tendon is Step 1 and is the easiest part of the shoulder exam (in my opinion), so we’ll go over that today! Stay tuned for future VOTWs for the rest of the shoulder exam.

Technique

• Have patient sitting in chair or side of the bed (see below)

• Use a linear high-frequency probe

• Have the patient flex elbow at 90 degrees with palm facing up and arm adducted

• Place the probe horizontally along the bicipital groove (proximal humerus) and find the echogenic long head of biceps tendon in transverse

• Rotate the probe 90 degrees to see the tendon in its long axis

• Look for disruptions in the tendon, fluid around tendon, or subluxation (tendon not in bicipital groove)

Image 1. Positioning for evaluating the biceps tendon

Artifact Corner

Tendons exhibit an artifact called anisotropy. This means the appearance of tendons can be different depending on the angle of insonation (the angle of the beam onto the object). It will look hyperechoic at one angle and hypoechoic at another angle. Don’t mistake this for a tendon tear or fluid. Fluid or tendons will not change in appearance with different angles of insonation.

So next time you have a patient with shoulder pain, take a quick look at the biceps tendon, you might find the answer right away!

Happy Scanning,

Your Sono Team

VOTW: Distal Radius Fracture

This week’s VOTW is brought to you by myself!

A 72 year old female came in the ED after a FOOSH and suffered a distal radius fracture w/ dorsal angulation seen on x-ray. A POCUS was performed which showed…

Clip 1 shows the dorsal distal radius with sudden cortical disruption and dorsal angulation consistent with the fracture site. The probe marker is facing towards the hand. Clip 2 shows a hematoma block performed w/ ultrasound guidance- the needle is seen entering the fracture site precisely where the fragments meet. Reduction of the fracture was then performed once adequate analgesia was achieved.

Image 1 is prior to reduction. Image 2 is s/p first attempt at reduction. Unhappy with the alignment, reduction was attempted one more time resulting in Image 3 where the alignment is improved. Post-reduction x-rays were obtained, the patient was placed in a sugar-tong splint and discharged with orthopedic follow up.

POCUS for distal radius fractures

In a small study of 83 patients with distal radius fractures, POCUS was 98% sensitive and 98% specific for identifying the fracture when compared to x-rays. Sensitivity and specificity of POCUS ffor the need for reduction was 98% and 100% respectively (1).

While POCUS may not replace x-rays for the management of fractures, it can assist with procedural guidance for hematoma blocks and can evaluate for the adequacy of reduction in real-time rather than waiting for the x-ray tech to come around in between reduction attempts.

How to Identify a fracture

• Use a linear high frequency probe

• Visualize the distal radius in its long axis from multiple planes

• Look for a disruption/angulation in the echogenic cortex

How to perform a ultrasound-guided hematoma block

• Obtain 10ml of lidocaine drawn up in a syringe, connect it to a saline lock and an injection needle

• Locate the fracture site using the linear probe

• Advance the needle into the skin in-line with the probe and guide it into the fracture site

• Have an assistant inject 10ml of lidocaine into the fracture site

References

Kozaci et al. Evaluation of the effectiveness of bedside point-of-care ultrasound in the diagnosis and management of distal radius fractures. American Journal of Emergency Medicine Volume 33, Issue 1, 2015, Pages 67-71

Happy Scanning!

Your Sono Team