Critical Point #1

In an effort to make you all better sonologists, I will start posting some QA teaching points. I call them "critical points" because I want you to look at the images with a critical eye. These are not meant to be derogatory, but I hope, that by illustrating an error and highlighting some excellent work, I will make you a better sonologist. The whole goal of bedside ultrasound is to expedite your diagnosis. We save our images so that our consultants can view them and come to the same conclusion that we did. So try to think of your images from your consultant's perspective. Show them what you see when you make your diagnosis!

Let's start with a video, below is a clip of a subxiphoid view of the heart. There are several things to note in this clip from a quality assurance perspective:

1. Are these images adequate? To determine this, answer the questions below:
a. Is the correct probe used?
b. Is the correct exam type used?
c. Is the depth set properly
d. Is the image centered on screen?
e. Is the complete organ visible?
f. Is the gain set correctly?
g. Is the image labeled correctly?
2. Can the correct diagnosis be made from this clip?
3. If so, what is the correct diagnosis?
4. What could the sonologist do to improve the visualization of the heart?

QA #1 from UF-Jax Emergency Medicine on Vimeo.

So let's look at this video clip critically and answer each of these QA points.

1. The sonologist used the correct probe for a cardiac scan (phased arrray) and had the correct exam type selected (cardiac). Although the heart is centered on the screen, the depth is set at only 16 cm (depending on the patient's girth, 21-26cm is usual). You will note that the posterior portion of the heart appears to be cut off. This is a really big problem if you are evaluating the heart for an effusion. You expect that the fluid will collect first in the most dependant portion of the pericardium- posteriorly in a supine patient. If you cut off the posterior wall of the heart, you may be unable to determine if there is an effusion present or not. Therefore, in this video clip, the complete organ is not visible. The gain is set perfectly and allows for the fluid filled portions of the heart to appear anechoic or black, while the myocardium stands out starkly more white or hyperechoic. By not over-gaining this image, we can determine that there are no visible clots in the heart which would appear as echogenic foci (grey areas). The clip is adequately labeled so that others not present at the time of the exam can know what the sonologist intended to image.

2. The diagnosis can be made by this clip, but it is a little subtle. Note that the left ventricle is located at the bottom right in the clip. As the ventricle contracts, a thin sliver of fluid in the pericardium can be visualized. Do not be fooled by only looking anteriorly, as the pericardial fat pad can mimic an effusion. The fat pad will appear as an anechoic stripe in the near screen on the parasternal long axis view (PSLX), anterior to the right ventricle. Without an anechoic stripe in the posterior pericardium, the diagnosis of an effusion cannot be made.

3. Correct diagnosis: Pericardial effusion. It is difficult to determine if tamponade is present from this view, but the right ventricle appears to move symmetrically. Pericardial tamponade can be diagnosed on ultrasound by the presence of right ventricular (RV) collapse. This can easily be seen using the PSLX view. The RV is located in the near field and the wall will collapse inward with each contraction. It will look like someone has placed their finger on the RV and pushed in toward to the septum at that one point. Always look for tamponade on any patient with an effusion. Usually it is the small, new effusions that will cause tamponade since the pericardium has not been stretched out to accommodate the fluid collection.

4. The sonologist did a fair job in this clip, but would really make the clip better by increasing the depth of field to allow the heart and pericardium to be completely visualized. Otherwise, good job!

December Case #3 Discussion

This patient has evidence of necrotizing fasciitis on ultrasound. He had plain films taken which illustrated gas in the tissues.

He was taken to the OR for debridement of the area and was noted to have purulent debris in both the volar and dorsal forearm compartments with resultant compartment syndrome. He had fasciotomies of both compartments and the excision of the purulent material. He subsequently underwent multiple debridements and eventually had a right shoulder disarticulation due to purulent material found throughout his forearm, elbow and biceps. His wound cultures grew out klebsiella and VRE.

Necrotizing Fasciitis

Necrotizing fasciitis (NF) is a rapidly spreading, progressive infection of the deep fascia with secondary necrosis of the subcutaneous tissues. Subcutaneous air is classically associated with NF due to gas forming organisms.

Cheng et al, noted that upper extremity NF has a higher mortality rate (35%). Mental status depression and respiratory distress on presentation were factors associated with higher mortality. Diabetes and other immunocompromised states are also risk factors.

On Ultrasound, NF appears to distort the facial layer, causing thickening of the subcutaneous tissue and muscle layer with hypoechoic fluid collections adjacent. Gas may also be visualized as a hyperechoic area with posterior shadowing (the hyperechoic area appears to fade into the shadow).




Cheng NC, Su YM, Kuo YS, Tai HC, Tang YB. Factors affecting the mortality of necrotizing fasciitis involving the upper extremtities. Surg Today. 2008;38(12):1108-13.

December Case #3

65 y/o AAM presents to the ED with complaints of elevated blood sugar and lethargy. Pt denies pain, SOB, N/V/D, or trauma.

PMHx: DM, HTN
PSHx: none

Meds: ASA, Norvasc, HCTZ, Lisinopril, Insulin

Allergies: NKDA

FamHx: none

SocHx: none

PE: BP 109/77, P 86, R 16, T 98.1, POx 96% (RA)

GEN: thin AAF, lethgargic

HEENT: PERR, dry MM, no JVD

CHEST: CTA B, nonlabored

CV: RRR, no M/R/G
ABD: soft, NTND, + BS

EXT: no C/C, + edema to R arm extending from wrist to mid humerus, min TTP, no ecchymosis or erythema, ROM difficult to assess secondary to lethargy

Bedside ultrasound of the RU Ext performed with the following findings:

What is the diagnosis?


Thanks to Dustin Brimblecom for submitting this case!

December Case #2 Discussion

The images indicate a peritonsilar abscess in this patient. The patient underwent incision and drainage with full resolution.

Peritonsillar Abscess

Peritonsillar abscess (PTA) is the most common deep space infection of the head and neck. It is a progression from tonsilitis to cellulitlis to abscess. It is often confused with peritonsillar cellulitis as they appear similar clinically. Ultrasound can be used to determine between the two without subjecting patients to blind needle aspiration. Using ultrasound to differentiate the two diagnoses is highly sensitive (>90%, Blavias et al, had 100%!) and specific (>80%). PTAs usually appear as a hypoechoic or complex cystic mass, suggesting a pus pocket. If a fluid pocket is not denoted, then peritonsillar cellulitis is confirmed and the patient may be started on antibiotics without needle aspiration.

To evaluate the patient for PTA using intraoral ultrasound, the patient is first anesthetized topically (we used a 4% lidocaine neb and hurricaine spray in this case). The endocavitary probe is covered with a non-sterile probe cover after gel is applied to the tip. The patient is seated with their head resting against the back of the bed or ENT chair and the probe is inserted into the mouth and directed to the affected tonsillar pillar. The area can be imaged in the transverse or longitudinal plane, although transverse imaging is easiest and used most often. The affected area is scanned from top to bottom localizing the abscess. The sonologist can also denote the size, depth and relation of the abscess to the vascular structures that lie adjacent. Furthermore, ultrasound can be used to guide the needle aspiration. Although a little cumbersome, real time ultrasound guidance ensures that the needle is in the correct location and not extending past to the vascular structures posterior.

Blaivas M, Theodoro D, Duggal S. Ultrasound-guided drainage of peritonsillar abscess by the emergency physician. Am J Emerg Med.2003;21:155-158.
Lyon M, Blaivas M.Intraoral ultrasound in the diagnosis and treatment of suspected peritonsillar abscess in the emergency department. Acad Emerg Med.2005;12:85-88.

December Case #2

38 y/o AAF presents to the ED with a sore throat for 2 weeks, which she states is getting worse. She admits to subjective fever but denies cough, SOB, N/V, dysphagia or drooling. She states that her voice sounds different.
PMHx: none
PSHx: none
Meds: none
Allergies: NKDA

PE:
GEN: overweight, AAF, NAD, speaks with a "hot potato" voice
HEENT: PERRL, EOMI, MMM, R tonsilar pillar edematous, no exudate, uvula angled to the L, mild LAD on R
CHEST: CTA B, nonlabored
CV: RRR, no M/R/G

Bedside ultrasound is performed on this patient and yields the following images:




What is the diagnosis?
Describe the technique used to obtain these images and the relevant anatomy.

Thanks to Christopher Mann for submitting this case!

DVT Ultrasound Lecture

Check out this SlideShare Presentation:

9 vascular us

View more presentations from Petra Duran-Gehring.

December Case #1 Discussion

This patient has a normal ultrasound of the deep veins of the lower extremity- common femoral vein, junction point at the saphenous vein (superficial circulation), profunda femoris and superficial femoral vein. However, the area to which he was most tender was along his medial thigh. At the point of the images and video, he had a small palpable knot. The resultant images indicate superficial thrombophlebitis.

Deep Venous Thrombosis

When evaluating a patient for DVT, we usually look only at the deep circulation of the leg. The picture below illustrates the veins of the leg. Notice that the superficial circulation (dark blue) joins with the deep veins (light blue) to become the common femoral vein (CFV).

Traditional ultrasound protocols scan through the CFV, the junction point with the saphenous vein, the profunda femoris and the superifical femoral vein (SFV), then look at the popliteal above the trifurcation in the calf, illustrating compressibility as they go. However, in this month's edition of the Annals of Emergency Medicine, Crisp et al, illustrate that compression ultrasound performed at 2 points only, CFV and popliteal, had a 100% sensitivity for DVT (link to article at bottom of page). Since previous studies have illustrated that DVTs never occur solely in the SFV, it is important to know that the CFV, and not the SFV, is visualized on the screen. Therefore, I advocate that you still scan caudal to cranial in the inguinal canal to locate the CFV. Scanning through the profunda and the junction point ensures that the CFV will not be mistaken for the SFV. Once the CFV is visualized, then video clips or split screen still images should be taken to illustrate compressibility.

Superficial Thrombophlebitis

On the other hand, superficial thrombophlebitis is characterized by a clot within the lumen of a superficial vein, which leads to inflammation of the walls of the vessels, as well as, the surrounding tissue. It is most commonly found in varicose veins of the lower extremity but can proliferate up the venous circulation. If it extends through the greater saphenous vein into the common femoral vein, then it may become a deep venous thrombosis (rare).

On Ultrasound the thrombosed vein wall appears thickened, lacks compressibility and may have a hyperechoic center, indicating clot. Due to the inflammation and edema, the surrounding tissue may show evidence of this as a cobblestone appearance on ultrasound.

In the original case, a superficial branch of the great saphenous vein is identified with visible clot and non-compressibility, about 1cm below the skin's surface.

To further illustrate superfical thrombophlebitis, here are images from another case, clearly demostrating a hyperechoic clot in the lumen with surrounding tissue edema and a lack of compresibility.

December Case #1

50 y/o WM presents to the ED with complaints of R leg pain for 3 days. He denies trauma or physical exertion. He admits to edema localized to the thigh, but denies calf swelling. Denies redness, warmth or pointing of the skin.
PMHx: HTN
PSHx: none
Social: denies ETOH, tobacco or drug use
Meds: HCTZ
Allergies: NKDA

PE: VS WNL
GEN: WNWD, WM, NAD
CHEST: CTA B
CV: RRR, no M/R/G
ABD: soft, NTND, +BS
EXT: no C/C, edema to R mid thigh with tenderness to palpation that extends to R calf, distal pulses 2+ bilaterally. No palpable cords noted

Bedside ultrasound is performed to rule out deep venous thrombosis:


What is your interpretation of this DVT study?

While scanning for DVT the patient states, "the pain is actually here" and points to the medial thigh. The area is then scanned and the following are noted:




What is the diagnosis?

November Case #4 Discussion

The longitudinal and transverse images of the bladder indicate a foreign body. In this case, the ruptured end of a suprapubic catheter. In the transverse view you see the end of the tubing, but in the longitudinal view you can make out the balloon still inflated.

Urology was consulted and a new suprapubic catheter was placed. The old one was later removed with cystoscopy and the end was noted to have been cut cleanly off.

This case illustrates an important point: You must always image any three dimensional structure in two planes. In this case it helped to identify that the suprapubic catheter was not only still in the patient's bladder, but that the balloon was still at least partially inflated.