ACCEPTABLE CONFIRMATION STUDIES

FAST

  • Consultative abdominal ultrasound

  • CT of the abdomen

  • MRI of the abdomen

Aorta

  • Consultative abdominal ultrasound

  • CT of the abdomen

  • MRI of the abdomen

  • Aortic angiography

Renal

  • Consultative renal ultrasound

  • CT of the abdomen

  • MRI of the abdomen

Obstetric

  • Consultative Obstetric ultrasound

Thoracic

  • Chest x-ray

  • CT of the chest

  • MRI of the chest

Musculoskeletal

  • X-ray of the body region being examined

  • CT of the body region being examined

  • MRI of the body region being examined

Ocular

  • CT of the orbits

  • MRI of the head/eye

Vascular

  • Vascular lab-performed consultative ultrasound

  • CT angiogram

  • Traditional angiography

Superficial

  • Consultative soft tissue ultrasound

  • X-ray of the body region being examined

  • CT of the body region being examined

  • MRI of the body region being examined

Level 1 Cardiac

  • Consultative Echocardiogram

  • CT of the chest

  • MRI of the chest

Advanced Cardiac

  • Consultative Echocardiogram

  • CT of the chest

  • MRI of the chest

DVT

  • Consultative DVT ultrasound

  • MRI of the lower extremity

  • CT venogram of the lower extremity

Gallbladder

  • Consultative RUQ ultrasound

  • CT of the abdomen

  • MRI of the abdomen

Abdominal

  • Consultative abdominal ultrasound

  • Abdominal CT

  • Abdominal MRI

Scrotal

  • Consultative scrotal ultrasound

  • CT of the scrotum/pelvis

  • MRI of the scrotum/pelvis

Non-pregnancy pelvic

  • Consultative pelvic ultrasound

  • MRI of the pelvis

  • CT of the pelvis


CORE APPLICATIONS: WHAT STUDY ARE YOU DOING?

AORTA

INDICATIONS:

Medical Necessity: Evaluate the aorta for presence or absence of aneurysm
Focused Question: Is there an abdominal aortic aneurysm?

REQUIRED IMAGES: Measure Outer Wall to Outer Wall at each location (clip and still image recommended)

1.) Transverse image at Proximal, Mid, and Distal Aorta

aorta 1 prox.png
aorta 2 mid.png
aorta distal.png

2.) Saggital or Longitudinal image at Distal Aorta and Bifurcation

 

RENAL

INDICATIONS:

Medical Necessity: Evaluate for hydronephrosis
Structures studied: Kidneys, including collecting system
Focused Question: Is hydronephrosis present? 

REQUIRED IMAGES:

Add Color Doppler to potential hydronephrosis to ensure it is not a vessel.
Evaluate for ureteral jets if any hydronephrosis seen.

1. Long and Short Axis View of Right and Left Kidney

1. Long and Short Axis View of Right and Left Kidney

2. Transverse and Saggital View of Bladder with Views of Ureteral Jets

2. Transverse and Saggital View of Bladder with Views of Ureteral Jets

 

HOW TO SCAN - RENAL

SCAN BILATERALLY

1.) Obtain video clip fanning through entire portions of both kidneys in both the longitudinal and transverse planes.

LEFT:

RIGHT:

2.) Obtain one static representative image.

STATIC LONGITUDINAL IMAGE OF KIDNEY WITHOUT HYDRONEPHROSIS

STATIC LONGITUDINAL IMAGE OF KIDNEY WITHOUT HYDRONEPHROSIS

 

If hydronephrosis is present (particularly bilaterally), scan the urinary bladder. If the bladder is distended, have the patient empty the bladder and repeat scan after 15 minutes.  

If there is any confusion as to the origin of fluid filled structures seen in the renal pelvis, apply color flow to differentiate vascular spaces from urinary spaces.


CARDIAC

INDICATIONS:

Medical Necessity: To assess for the presence or absence of pericardial effusion. To assess for the presence or absence of cardiac activity.
Structures studied: Heart, pericardium.
Focused Question: Is a pericardial effusion present? Is there cardiac activity?

REQUIRED IMAGES:

Parasternal Long Axis (PSTL), Parasternal Short Axis (PSAX), Apical 4 Chamber (AP 4/5), Subxiphoid, and IVC Images

cardiacus.png
 

HOW TO SCAN - CARDIAC

1.) Obtain at a minimum, video clips of the sub-costal and parasternal long axis views of the heart.

Additional views may include parasternal short axis and apical 4 chamber.

2.) Obtain one static representative image.

SUB-COSTAL VIEW STATIC IMAGE WITHOUT PERICARDIAL EFFUSION

SUB-COSTAL VIEW STATIC IMAGE WITHOUT PERICARDIAL EFFUSION

 

RUQ

INDICATIONS:

Medical Necessity: Evaluate for gallstones and dilated common bile duct and sonographic signs or cholecystitis, such as “positive sonographic Murphy’s sign,” thickened gall bladder wall, and pericholecystic fluid

Structures studied: Gallbladder (GB), common bile duct

REQUIRED IMAGES:

Short Axis, Long Axis, Common Bile Duct

rug short.png
rug long.png
rug common.png

HOW TO SCAN - RUQ

1.) Obtain a video clip of the GB in it’s entirety, in both the longitudinal and transverse planes.

 

2.) Obtain a static image of the GB in the transverse plane with a measurement of the anterior GB wall.

TRANSVERSE VIEW OF GALLBLADDER

TRANSVERSE VIEW OF GALLBLADDER

ANTERIOR WALL MEASUREMENT IN THE TRANSVERSE PLANE

ANTERIOR WALL MEASUREMENT IN THE TRANSVERSE PLANE

3.) Obtain a static image of the Common bile duct (CBD).

COMMON BILE DUCT MEASUREMENT

COMMON BILE DUCT MEASUREMENT

 

CRITICAL MEASUREMENTS

COMMON BILE DUCT

  • <5mm-normal in patients up to age 50 (Add 1 mm for every decade of life thereafter)

  •  5-7mm equivocal

  •  >7mm-dilated

GALLBLADDER WALL

  •  <3mm-normal

  •  3-4mm-equivocal

  •  >4mm-dilated

Note: The left lateral decubitis, in addition to the supine position, is generally superior for the GB and CBD visualization.


FAST

INDICATIONS:

Medical Necessity: Evaluate for intraperitoneal or pericardial fluid
Structures studied: Hepatorenal space, splenorenal recess, pericardial space, and pelvic views.

REQUIRED IMAGES:

3 Components to a FAST Exam (include each as clinically indicated) : Abdomen, Cardiac, Thoracic

1.) Abdomen

  • RUQ - include hepatorenal space, sub-diaphragmatic space, and inferior edge of the liver

  • LUQ -  include splenorenal space, sub-diaphragmatic space, left paracolic gutter

  • Pelvis - transverse and sagittal views

fast 3.jpg
 

2.) Cardiac

  • Obtain any one of the Parasternal Long Axis, Apical 4 Chamber, or Subxiphoid Views

 

3.) Thoracic

  • Anterior Chest - Right and Left

  • Lateral Inferior Chest, Coronal View - Right and Left

    • Visualize Diaphragm and Spine.  These can be obtained concurrent with abdominal RUQ and LUQ views

 

HOW TO SCAN - FAST

1.) Video in the longitudinal plane, fanning through Morrison’s pouch (hepatorenal space) to include the inferior tip of the liver/inferior pole of right kidney.

2.) Video clip fanning through the bladder in both the longitudinal and transverse planes. 

3.) Video clip in the longitudinal plane scanning through the spleen and kidney. Must include diaghram, spleno-renal space, and inferior tip of the spleen/lower pole of left kidney.

4.) Video clip of the subxiphoid cardiac view in the transverse plane.

5.) If subxiphoid view is techniquely inadequate, a video clip of the parasternal long axis will suffice. 

6.) Obtain one static representative image.

HEPATORENAL SPACE STATIC IMAGE ON FAST EXAMINATION

HEPATORENAL SPACE STATIC IMAGE ON FAST EXAMINATION


EARLY PREGNANCY


Click here for the Early Pregnancy Ultrasound Algorithm

INDICATIONS:

Medical Necessity: Confirm intrauterine pregnancy (IUP) and evaluate for signs of ectopic pregnancy.
Structures studied: Uterus and its contents, vesicouterine space, and rectouterine space (Pouch of Douglas).

REQUIRED IMAGES: Transabdominal and Transvaginal Views

Transabdominal Views - Transverse and Sagittal Views of the Uterus

preg transabd.png
 

Transvaginal Views - Transverse and Sagittal Views of the Uterus

preg transvag.png
 

If Intrauterine Pregnancy Visualized, Document FHR and Crown Rump Length

preg - iup.png

HOW TO SCAN - EARLY PREGNANCY

BEGIN TRANSABDOMINALLY

1.) Obtain a video clip fanning through the uterus in its entirety in the longitudinal and transverse planes. Assess for uterine lie, presence or absence of free fluid and evidence of an IUP.

 

IF THE TRANSABDOMINAL SCAN IS NON-DIAGNOSTIC FOR AN IUP, PERFORM A TRANSVAGINAL SCAN. 

1.) Obtain a video clip fanning through the uterus in both the longitudinal and transverse (coronal) planes.

2.) Obtain one static representative image. 

NO  GESTATIONAL SAC,  NO  INTRAUTERINE PREGNANCY

NO GESTATIONAL SAC, NO INTRAUTERINE PREGNANCY

GESTATIONAL SAC + YOLK SAC + SURROUNDED BY MYOMETRIUM* = IUP

GESTATIONAL SAC + YOLK SAC + SURROUNDED BY MYOMETRIUM* = IUP

GESTATIONAL SAC BUT NO EVIDENCE OF YOLK SAC OR FETAL POLE = NO IUP

GESTATIONAL SAC BUT NO EVIDENCE OF YOLK SAC OR FETAL POLE = NO IUP

GESTATIONAL SAC + YOLK SAC + FETAL POLE + SURROUNDED BY MYOMETRIUM* = IUP

GESTATIONAL SAC + YOLK SAC + FETAL POLE + SURROUNDED BY MYOMETRIUM* = IUP

To be diagnostic for an IUP, the uterus must be scanned in it’s entirety in 2 orthogonal planes showing a minimum of a gestational sac (GS) containing a yolk sac. The sac must be confirmed to be located within the endometrial cavity. This is best determined by demonstrating continuity between the endometrial cavity containing the gestational sac and the endocervical canal.  Assessment for myometrial mantle all around the sac in 2 orthogonal planes must be confirmed. *If the myometrium is <6 mm, this is concern for a corneal/interstitial or ectopic pregnancy.


BLADDER

bladder+transverse.png
bladder+saggital.png

LUNG

If evaluating only for pneumothorax bilateral anterior chest clips are sufficient. M-mode can also be utilized.

If evaluating only for pleural effusion bilateral lateral inferior chest views that demonstrate the diaphragm are sufficient.

If evaluating for parenchymal disease 10 zones should be assessed: Right and left anterior superior, anterior inferior, lateral superior, posterior inferior, lateral inferior.

Lung+zones.png
lung Lateral+Inferior.png

LOWER EXTREMITY VENOUS

Obtain clips demonstrating compression of the vein. Another option is to utilize dual mode and obtain side-by-side still images of each site uncompressed and compressed.

le+dvt.png

PROCEDURAL ULTRASOUND

Needle Visualization - A Critical MicroSkill

Following a needle with direct ultrasound visualization can seem deceptively easy at first - it's right there on the screen right?!  However, accurately following the tip of a needle traversing near vitally important neurovascular structures in 3 dimensions on a 2D screen requires a firm understanding of the inner workings of ones ultrasound machine, the physics of ultrasound, and the characteristics of the needle you are using.  Though an understanding of these concepts and deliberate practice you can master a microskill critical to the performance of a number of ultrasound-guided procedures.

Understanding and Optimizing Your Ultrasound Machine

 

DVT

Lower Extremity Compression Ultrasonography to Assess for Deep Vein Thrombosis

Objectives - Assess for compressibility of:

  1. The common femoral vein

  2. The saphenofemoral junction

  3. The femoral vein

  4. The deep femoral vein

  5. The popliteal vein and its trifurcation

The goal is to assess the compressibility of the femoral vein at the saphenous-femoral junction (SFJ), the common femoral vein (CFV) and the femoral vein/deep femoral vein (FV/DFV), as well as of the popliteal vein and the popliteal trifurcation. Inability to compress at any of these points is suggestive of deep vein thrombosis (DVT)in that vein.Clots may sometimes be visualized ashyperechoic density within the vessel, but since some are anechoic, failure to directly visualize a clot does not rule it out. However, regardless of its echogenicity, the vein will not compress when a clot is present.

Background:
Unilateral leg pain and/or swelling is a commonly seen complaint in the Emergency Department. Ultrasound is the gold standard for diagnosis of DVT. While this is non-invasive and relatively inexpensive compared to other imaging studies, it can be time consuming to send patients to the radiology or vascular lab for a formal full-length lower extremity study. Moreover, there are some institutions that do not have radiology-performed ultrasonography available at all hours. Emergency physicians performing bedside 2-point compression ultrasound can save time and expedite safe dispositions.A 2004 prospective, single-blind, observational study examinedthe time savings of ED bedside US vs radiology studies which showed that the mean time from triage to disposition in the former group (95 minutes) was significantly less (P<0.0001) than in the latter group (220 minutes) with excellent agreement between the studies.1

Numerous studies have demonstrated the validity of limited ultrasound imaging performed by emergency physicians. Burnside et al. performed a systematic review of studies on the diagnostic performance of emergency physicians in DVT ultrasound which found a pooled sensitivity and specificity of 95% [95% CI= 0.87 to 0.99]and 96%[95% CI = 0.87 to 0.99], respectively.2 In another systematic review and meta-analysis, Pomero et al. looked at the accuracy of emergency physician-performed ultrasound (EPPU) for the diagnosis of DVT compared to radiology performed US or angiography. They found a weighted mean sensitivity of EPPU of 96.1% (95% CI 90.6-98.5%) and weighted mean specificity of 96.8% (95% CI 94.-98.1%).3

The emergency-physician performed DVT study focuses only on proximal deep veins of the leg above the knee and does not evaluate for distal or calf vein thrombosis. The evaluation for and treatment of distal deep vein thrombosis varies among practitioners and institutions.

dvt veins lef.jpg

Anatomy:
Below the iliac ligament the iliac vein becomes the common femoral vein. As this vein travels distally, the saphenous vein joins it from its more medial and superficial position. The common femoral vein then bifurcates into the deep femoral vein and the femoral vein.

The femoral vein was previously known as the superficial femoral vein, but that terminology was dropped to maintain clarity that this is a deepvein. The femoral vein dives into the adductor canal and becomes the popliteal vein distally. The popliteal vein traverses the popliteal space behind the knee and trifurcates into the posterior tibial vein, anterior tibial vein and the peroneal vein. Venous anatomy can have many variants and the variation increases in distal veins.

How to perform the exam:
Patient Positioning:Have the patient lie supine or recumbent with leg of interest resting in external rotation at the hip with the knee slightly flexed. You may be able to improve visibility of vessels by placing patient in slight reverse Trendelenburg to encourage venous pooling/distention.When assessing the popliteal vessels, the knee should be more flexed with the hip in flexion and external rotation.

dvt assess fem.jpg

Probe selection:
High frequency linear transducer. Convention is to orient the probe so that the indicator is directed to the patient right in the transverse position.

 
 

The views:
In the groin the points of compression from proximal to distal are:

  • The saphenous-femoral junction (SFJ)

  • The common femoral vein (CFV)

  • The femoral vein/deep femoral vein (FV/DFV)

In the popliteal space the points of compression from proximal to distal are:

  • Popliteal vein proximal to the Popliteal trifurcation: where the popliteal divides into the anterior and posterior tibial veins and peroneal vein.

Begin with the probe in the transverse orientation just distal to the inguinal ligament. The femoral vessels are approximately at the midpoint between the pubic symphysis and anterior superior iliac spine. You can also palpate the femoral artery to identify a starting point.The veinwill typically lie medialand superficialto the artery. The vein will appear as a round, thin walled, hypoechoic structure, while the artery will appear similar but with a thick wall and often has visible pulsation. Using evenly applied pressure, push down with the transducer to visualize the compression (or lack thereof) of the vein. If the vein does not compress completely, an intraluminal thrombus is present.

Common femoral vein and artery without Compression

Common femoral vein and artery without Compression

Common femoral vein and artery with compression

Common femoral vein and artery with compression

After identifying the femoral artery and vein and ensuring complete compression, move the transducer caudad until you find the great saphenous-femoral junction. The saphenous joins the common femoral vein from a more superior position at the saphenofemoral junction. Compress to ensure complete compressibility. If there is lack of compression in the proximal great saphenous vein suggesting thrombosis this is also treated as a deep vein thrombosis and as these have a high risk of propagating into the femoral vein.

 
The saphenofemoral junction: CFA = common femoral artery, CFV = common femoral Vein, GSV = great saphenous vein

The saphenofemoral junction: CFA = common femoral artery, CFV = common femoral Vein, GSV = great saphenous vein

 

Continue to slide caudad until the common femoral artery and vein are visualized alone and repeat the compression test.  Lastly, slide the probe until the common femoral vein separates and the femoral and deep femoral veins are seen in the same image. Finding this bifurcation can be occasionally be difficult. Typically, the common femoral artery will bifurcate in a more cranial position than the common femoral vein. Visualizing the common femoral vein in the long axis can often assist in identifying the bifurcation of the femoral vein.

 
At the level of the femoral vein and deep femoral veins; CFA = common femoral artery, FV = femoral vein, DFV = deep femoral vein

At the level of the femoral vein and deep femoral veins; CFA = common femoral artery, FV = femoral vein, DFV = deep femoral vein

 
A clip demonstrating the probe sliding caudad from the common femoral vein to the deep femoral vein and femoral vein.
A Compression at the level of the deep femoral vein and femoral vein.

Move the probe to the popliteal fossa for evaluation of the popliteal vein and trifurcation.  Maintain the probe in the transverse orientation with the indicator directed to the patient’s right.  The vein normally lies superficial to the artery (Remember: “Pop on top” meaning that the popliteal vein is more superficial to the artery in your image).  It can sometimes be challenging to find the popliteal vein and doing so can be facilitated by placing the patient in the prone position and passively flexing the knee. If the operator is applying too much pressure, it can be difficult to visualize the vein as it may already be compressed.  Once the vein is identified and compressed, the final view is obtained by sliding the probe distally until the vein divides into three smaller vessels.   

In the popliteal space; PV = popliteal vein, PA = popliteal artery

In the popliteal space; PV = popliteal vein, PA = popliteal artery

Compression at the popliteal vein

Troubleshooting:

  1. As mentioned above, patient positioning can help improve the ability to visualize the vessels.  Options include placing patient in reverse Trendelenburg or having them hand the leg over the edge of the bed. 

  2. Finding the appropriate anatomy in obese patients can be difficult.  In these patients you may need to use the curvilinear probe.

  3. Beware the thrombus mimics! 

    • Rouleaux formations are an accumulation of red blood cells overlying venous valves and can easily be mistaken for DVT.  This is sometimes referred to as the “sludge sign.”  However, unlike DVT, rouleaux formations are compressible and compression of distal veins will clear the formation, while DVT will not clear.

    • Lymph nodes will appear as round structures with echogenic centers that appears like a DVT.  However, these are non-compressible, discrete ovoid structures and usually do not have an associated artery adjacent to them the way a vein will. 

Pathology:

The appearance of echogenic material within the vessel lumen is indicative of probable thrombus.  If the thrombus is chronic you still may seem some degree of compressibility of the lumen.  Chronic DVTs are of less concern, however, unless the patient has a known prior DVT in the vessel in question, it is best to treat as acute.

A DVT at the common femoral vein. Note inability to compress the vein. The artery is seen on the right side of the screen with a small calcified plaque within it.
A DVT at the sapheno femoral junction. The veins are not compressible despite adequate pressure to deform the artery.
A non-occlusive thrombus at the common femoral vein. Notice how the vein compresses some, but incompletely. This is why it is important to completely compress the vessel when evaluating for DVT.
This is a non-occlusive thrombus at the popliteal vein

Pattie’s Pearls:

  • The indicator is imperative. Remember: NAVEL. Nerve, artery, vein, empty space, lymphatics

  • For finding the great saphenous vein, remember that it has a medial placement relative to the common femoral vein

  • Try to be as perpendicular as you can when compressing. 

  • If you are not sure if you are compressing the vein adequately, check for compression of the artery. 

  • Two compressions per clip ensure that anyone viewing your images has a chance to appreciate full compression of the vein.

  • For a difficult body habitus, decrease the frequency to increase the penetration.

  • Adequately remove clothing. Don’t compromise your exam battling boxers or Spanx.

  • Having trouble seeing the popliteal vein? Let up on your pressure and increase the depth.

  • Having trouble compressing or keeping the popliteal on the screen while you do? Try putting on hand on the patient’s knee while compressing, place the patient on their side or lay them prone.

  • Last but not least, don’t forget to label your images!!

References:

  1. Theodoro D, Blaivas M, Duggal S, Snyder G, Lucas M. Real-time B-mode ultrasound in the ED saves time in the diagnosis of deep vein thrombosis (DVT). The American journal of emergency medicine. 2004;22(3):197-200.

  2. Burnside PR, Brown MD, Kline JA. Systematic review of emergency physician-performed ultrasonography for lower-extremity deep vein thrombosis. Academic emergency medicine : official journal of the Society for Academic Emergency Medicine. 2008;15(6):493-498.

  3. Pomero F, Dentali F, Borretta V, et al. Accuracy of emergency physician-performed ultrasonography in the diagnosis of deep-vein thrombosis: a systematic review and meta-analysis. Thrombosis and haemostasis. 2013;109(1):137-145.

  4. Ultrasound for Deep Venous Thrombosis. EB Medicine  https://www.ebmedicine.net/topics.php?paction=showTopicSeg&topic_id=252&seg_id=4864, 2018.

  5. Ultrasound Guidelines: Emergency, Point-of-Care and Clinical Ultrasound Guidelines in Medicine. Annals of emergency medicine. 2017;69(5):e27-e54.

  6. Lars J Grimm M, MHS. Bedside Ultrasonography in Deep Vein Thrombosis. Medscape 2017; https://emedicine.medscape.com/article/1362989-overview#a3.

  7. Kobner S. PV Card: Focused Deep Vein Thrombosis (DVT) Ultrasound. ALiEM 2015; https://www.aliem.com/2015/03/pv-card-focused-deep-vein-thrombosis-dvt-ultrasound/.